Jonathan Tze-Wei Ho, M.A., M.D.

• Assistant Professor of Anesthesiology and Critical Care Medicine

https://www.hopkinsmedicine.org/profiles/results/directory/profile/10003132/jonathan-ho

T2W images are superior to T1W images because of better visualization of the bright signal intensity of inflammatory change associated with acute appendicitis asthma breathing test ventolin 100mcg without a prescription. On fat saturated asthma symptoms metallic taste buy 100mcg ventolin free shipping, gadolinium enhanced T1W images enhancement of the wall of the inflamed appendix is well seen will asthmatic bronchitis go away safe 100mcg ventolin. In the rest of the patients asthma treatment for patient with feeding tube 100 mcg ventolin visa, who are usually young asthma symptoms and causes buy ventolin 100 mcg with mastercard, old or pregnant the clinical picture may be obscure and diagnosis is sometimes impossible until laparotomy asthma guidelines expert panel report 3 order ventolin paypal. It is in this group of patients that imaging plays an important role and cross-sectional imaging has a distinct advantage over clinical assessment. Ultrasound had a pooled sensitivity and specificity of 88% and 94%, respectively in children and 83% and 93%, respectively in adults. However, it is operator dependent and a small but finite number of false negative results occur regardless of expertise. This includes elderly, immunosuppressed patients and those with prolonged clinical symptoms (>72 hours duration) or a high fever and marked leukocytosis. Ultrasound is also the initial imaging modality in pregnant women with suspected appendicitis. However, several factors may limit its usefulness; the appendix may be displaced and adequate graded compression maybe difficult in the presence of the gravid uterus. A precursor to the formation of a mucocele is obstruction of the appendiceal lumen which can occur due to fecalith, foreign body, carcinoid tumor, adhesions, endometriosis and mucinous cystadenoma or cystadenocarcinoma. There is formation of a globular or reniform smooth walled, broad based mass invaginating the cecum, with frequent calcification in the wall or substance of the mass. Barium studies will show nonfilling of the appendix with a globular, smooth, broad-based filling defect that invaginates into the cecum. Myxoglobulosis is a rare variant of mucocele in which the appendix is filled with clusters of pearly white mucous balls intermixed with mucous. Unlike appendiceal calculi, the calcified spherules in myxoglobulosis are usually annular and nonlaminated, shift within the mucocoele and can layer in the upright position. The surface may be smooth, lobulated or irregular, so that differentiation from a mucosal lesion of the cecum is often difficult, if not impossible. The importance of recognising the defect lies in differentiating an inverted appendiceal stump from a significant lesion. The inverted stump rarely causes symptoms, although cases of ulceration and intussusception have been reported. It produces an oval, round, or finger like filling defect projecting from the medial wall of the cecum alongwith nonvisualization of the appendix. Such a differentiation may be greatly aided if a specific attempt is made to fill and visualize the appendix by appropriate pressure over the cecum during the barium enema examination. Should the defect remain constant and homolateral to the ileocecal valve on two examinations, definite differentiation cannot be made between irreducible intussusception, appendiceal and cecal masses. Although rare, a variety of primary neoplasms can arise from the appendix (Table 2). Carcinoids are the most common and represent upto 80% of all appendiceal neoplasms. Over 70% of these tumors are found in the distal third of the appendix and are <1 cm in size. Although carcinoid tumors are considered potentially malignant, metastatic deposits and carcinoid syndrome with an appendiceal primary site are exceedingly rare. Pseudomyxoma peritoneii is a diffuse intraperitoneal accumulation of gelatinous ascites. Some investigators posit that nearly all true cases of pseudomyxoma peritoneii are appendiceal in origin and that associated ovarian lesions usually represent metastatic disease, although this is controversial. Magnetic resonance imaging additionally enables differentiation between mucinous and fluid ascites on T2W images. The colonic (nonmucinous) adenocarcinomas are much rarer than the mucinous adenocarcinomas. These tend not to form mucoceles, rather they manifest clinically with appendicitis, related to malignant luminal obstruction. The appendix becomes massively enlarged but typically maintains its vermiform appearance. Investigation and analysis of the position, fixation, length and embryology of the vermiform appendix. Computed tomography evaluation of the normal appendix: Comparison of low-dose and standard dose unenhanced helical computed tomography. Obstruction of the appendix vermiformis causing acute appendicitis: An experimental study in the rabbit. The incidence of radiographic findings in acute appendicitis compared to 200 normal abdomens. Graded compression sonography with adjuvant use of a posterior manual compression technique in the sonographic diagnosis of acute appendicitis. Operator-dependent techniques for graded compression sonography to detect the appendix and diagnose acute appendicitis. Ultrasonography and limited computed tomography in the diagnosis and management of appendicitis in children. Mucosal Hyperplasia, Mucinous cystadenoma and Mucinous Cystadeno-carcinoma of the Appendix. Appendiceal tumors: retrospective clinicopathologic analysis of appendiceal tumors from 7,970 appendicectomies. Primary neoplasms of the appendix: Radiologic spectrum of disease with pathologic correlation. Presently, the type of surgical resection chosen depends largely on the segmental localization of the hepatic lesion. This article outlines the gross and segmental liver anatomy along with the imaging and surgical implications. It introduces the various imaging techniques that are used to evaluate this organ which today occupies the center stage of gastrointestinal radiology. In the center of each segment there is a branch of the portal vein, hepatic artery and bile duct. In the periphery of each segment there is vascular outflow through the hepatic veins. The anatomy of the liver can be detailed based on its external appearance or based on its vascular and biliary architecture. It has two major surfaces, a superior or diaphragmatic surface and an inferior or visceral surface. On the superior surface, the falciform ligament separates the liver into a larger right lobe and a smaller left lobe. At the porta hepatis the main portal vein, the proper hepatic artery, and the common bile duct are contained within investing peritoneal folds known as the hepatoduodenal ligament. The right portal vein has an anterior branch that lies centrally within the anterior segment of the right lobe and a posterior branch that lies centrally within the posterior segment of the right lobe. The liver is divided into eight functionally independent segments based on the hepatic veins and branches of the portal vein. The dashed line represents the transverse plane intersecting the liver at the level of the portal vein bifurcation separating the superior from the inferior hepatic segments 1276 Section 3 Gastrointestinal and Hepatobiliary Imaging hepatic vein divides the right lobe into anterior and posterior segments. Middle hepatic vein divides the liver into right and left lobes (or right and left hemiliver). The Bismuth-Couinaud classification also defines a so called portal vein plane as the transverse plane intersecting the liver at the level of the portal vein bifurcation into the right and left branches. Segment V lies between the middle and right hepatic veins below the portal vein plane. Unlike the other segments of the liver, it receives branches from the main trunk as well as both the right and left branches of the portal vein. This special vascularization is a distinctive characteristic of segment I and is the reason for its hypertrophy in patients with cirrhosis and hepatic venous outflow tract obstruction. Recent advances in hepatic surgery have made anatomic resections along these planes possible while minimizing morbidity and blood loss. This nomenclature is an invaluable tool for both the radiologist and surgeons, allowing them to define the location of tumors and their relationship with major vascular structures. Major resections of up to 75% of the liver can be performed provided the future liver remnant is not functionally compromised. The liver regenerates following extended hepatectomies provided two or three adjacent segments remain. Sonography is ideally suited to study the internal architecture of a focal mass and distinguish a solid from a cystic lesion. Some lesions are known to have characteristic sonographic morphology and the technique helps to narrow the differential diagnosis and triage patients for further imaging workup. The details of sonographic features of different pathologies will be discussed in subsequent chapters. The addition of color Doppler flow imaging further helps in characterizing mass lesions and assessing patency of vessels. Technique the liver is usually scanned in the supine or left decubitus position with a 3. The subcostal approach may not suffice in all patients and intercostal scanning may have to be done with a small footprint transducer. An attempt is made to delineate the venous landmarks so that all the liver segments are sequentially scanned. The portal vein, common duct and hepatic artery need to be evaluated and if available, color Doppler should be used for this purpose. Color Doppler and particularly power Doppler are very useful to assess the vascularity of focal liver lesions aiding in the characterization of these lesions. The recent advances in ultrasound technology include multifrequency electronic transducers which have multiple and variable focal zones, tissue harmonic imaging and ultrasound contrast agents. Both, the gas they contain (usually air or a perfluoro compound) and their stabilizing shell (denatured albumin, surfactants or lipids) are critical to render them sufficiently stable so that they survive for several minutes after injection. Low mechanical index and intermittent imaging are employed to obtain sufficient contrast enhancement. Harmonic color and power Doppler imaging and pulse inversion techniques are powerful sonographic contrast-specific techniques. Therefore, the mere visualization of parallel channels in the liver parenchyma does not indicate biliary dilatation. This level has been used because of the consistent acoustic window provided by the surrounding liver which ensures reproducibility of the measurement. Bile ducts run parallel to portal vein branches, but their location in relation to veins is variable and the axiom that ducts are always anterior to portal vein branches is not correct. Its major impact has been in patients with colorectal malignancy with liver metastases undergoing surgery. Intraoperative ultrasonography is used to accurately identify liver metastases and guide surgical resection. It is also useful to localize deep seated lesions that have been localized on preoperative imaging but cannot be palpated by the surgeon. The probe is applied directly to the liver surface and no gel or acoustic coupling agent is necessary. The liver is scanned from the dome to the caudal edge and from left to right in a sequential manner. Color Doppler can be coupled with the gray scale scan and is very useful to identify vascular landmarks and assess their patency. Intraoperative ultrasonography provides the operating surgeon with useful real-time diagnostic and staging information that may result in an alteration in the planned surgical approach. Current applications for this technique include tumor staging, metastatic survey, guidance for metastasectomy and various tumor ablation procedures, documentation of vessel patency, evaluation of intrahepatic biliary disease and guidance for liver transplantation. The circular structure anterior to the portal vein is the hepatic artery seen in cross section (arrowhead) Computed Tomography Computed tomography has for long been the modality of choice for evaluation of focal liver lesions. The late arterial phase corresponds to initial opacification of the portal-venous system. The phase of maximum hepatic parenchymal enhancement and hepatic venous opacification occurs about 45 seconds after the beginning of the pure early arterial phase. Acquisition parameters, specifically, table speed per rotation and scan rotation speed are set to allow full coverage of the liver in less than 8 seconds. Note the hepatic vein appears as a focal lesion on the early and late arterial phases but normally fills in during the portal-venous phase (arrows) performed, one each during the early arterial phase (20 seconds after injection of contrast medium), late arterial phase (30 seconds after the initiation of injection) and portalvenous phase (60 seconds after the start of injection). Accurate acquisition timing for multiphasic imaging depends on the assessment of circulation time in individual patients. This assessment is made by using either a preliminary injection of a small bolus of contrast material ("mini-bolus injection") or online bolus tracking software. If only two phases are planned through the liver (late arterial and portalvenous), then the late arterial-phase scan can be triggered following a delay of 10 seconds after peak aortic enhancement time. The normal liver appears homogeneous and has a density greater than spleen, pancreas and kidneys due to the high concentration of glycogen in liver. Increased density of liver may be seen in hemochromatosis and glycogen storage diseases, whereas decreased density is most often related to fatty infiltration of the liver. The fissure of the ligamentum venosum separates the left lobe and the caudate lobe.

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Increased volume coverage is combined with thinner slice thickness to obtain better quality volume data sets for three dimensional (3D) images asthma questions and answers ventolin 100mcg mastercard. Decreased gantry rotation time provides reduced scanning times and increased coverage along the Z-axis asthma definition 999 cheapest generic ventolin uk. The difference between the start of contrast medium injection and the start of scanning is referred to as delay time asthma 3d animation buy ventolin amex. Isotropic Data Acquisition and Increased Spatial Resolution Isotropic data acquisition is defined as obtaining images with equal voxel size in three axes asthmatic bronchitis reasons ventolin 100 mcg visa. Impaired renal perfusions with focal reduction of the nephrogram include renal infarction asthma nclex questions purchase ventolin without a prescription, blunt renal trauma and acute pyelonephritis asthma symptoms coughing order ventolin without a prescription. In acute pyelonephritis, hypoperfusion is combined with reduced tubule transit rates due to inflammatory obstruction. Delayed perfusion of the renal tubule system is visualized as a striated nephrogram of the infiltrated parenchyma. An initially reduced density and slowed temporal progression of the three phases of the nephrogram is caused by significant stenoses of the main renal artery, acute obstruction of the renal vein and acute ureteral obstruction. The normal nephrogram with homogeneous enhancement of the renal parenchyma is seen on the left side 1522 Section 4 Genitourinary Imaging glomerular filtration rate and tubular stasis caused by severe systemic hypotension. In this phase, while the intensity of the nephrogram declines, excretion of the contrast medium permits opacification of the calyces, renal pelvis, and ureters. The opacification of the renal collecting system allows the depiction of intraluminal pathology. The presence of "soft time rim sign", namely, a circumferental rim of soft tissue attenuation surrounding a calcification is a reliable indicator that the calcification in question represents a calculus within the ureter. The location of the tumor may also be helpful in the diagnosis and characterization of solid renal masses. Renal cell carcinoma is frequently located at the periphery or near the corticomedullary junction of the kidney as it originates in the renal cortex, while transitional cell carcinoma extends into the kidney from the renal pelvicalyceal system and occurs more centrally in the kidney. Urothelial Tumors Transitional cell carcinoma is the most common malignant neoplasm of the urotheluim. A filling defect in the renal pelvis or ureter can be caused by a neoplasm, calculus, clot, mycetoma or vascular impression. The entire course of both upper and lower moiety must be demonstrated as well as the ectopic opening. Often the upper moiety with lower ectopic opening is hydronephrotic with a hydroureter. However, because of radiation dose a three-phase protocol is considered sufficient. Thus in a single "nephropyelographic phase" acquisition, the renal paremchyma (nephrographic phase) and the collecting system, ureters and bladder (pyelographic phase) are assessed. Volume rendered image in the excretory phase; (B) Depicting the fused low lying ectopic kidney. External compression is not recommended in patients with abdominal pain or in patients with history of urinary tract obstruction, radical cystectomy, recent surgery and aortic aneurysm. The benefits are outweighed by the added inconvenience and discomfort to the patient. The administration of intravenous diuretic has been reported to increase ureteric distension. The importance of the state of the art user friendly workstations cannot be overemphasized. These reformats are also useful in the characterization of urinary tract anomalies. Maximal opacification of the renal arteries and veins allows confident diagnosis of venous extension of tumoral tissue. A sudden change in caliber of the renal vein and the presence of a clot within collateral veins are useful ancillary signs. Direct continuity of the thrombus with the primary tumor and heterogeneous enhancement of the thrombus with contrast indicate tumoral thrombus. Accurate demonstration of the arterial anatomy is useful in selected cases to plan nephron sparing surgery. The nephrographic phase is the most useful for detecting renal masses and for characterizing indeterminate lesions. A small lesion can be detected that may blend with the cortex on corticomedullary images. Sometimes this level of enhancement can be seen in some benign lesions such as complicated cysts. Measurement of wash out of contrast material from a lesion at 15 minutes may allow differentiation between hyperdense cysts and renal neoplasm. Alternately, a hyperdense renal cyst shows no change in density between corticomedullary and delayed phase images. The images can be viewed in multiple planes and orientations to define the tumour and its relationship to the renal surface, the collecting system and adjacent organs. Active hemorrhage is ill-defined or flame or waterfall shaped with an associated fresh hematoma which often shows dependent or circumferential layering of older and fresh hemorrhage. Excretory phase image; (B) depicting the opacified pelvicalyceal system and extravasation of contrast in the perinephric hematoma suggesting rupture of the pelvicalyceal system collecting system. Regardless of their calcium content, almost all urinary tract calculi are radiopaque on noncontrast scans. To decide whether or not a distal ureteral stone is in the ureterovesical junction or in the bladder, prone position imaging can be useful. Pelvic phleboliths, arterial vascular calcification, calcified vas deferens and a calcified appendicolith can be considered a differential diagnosis of ureteric calculi. Phleboliths often show a central lucency, whereas true calculi are as dense or more dense at the center than at the periphery. Another useful sign for diagnosing phlebolith is the comet-tail sign, which is a linear or curvilinear soft tissue structure represented by the noncalcified vessel, extending from an abdominal or pelvic calcification; its positive predictive value for phlebolith is 100%. When a definite diagnosis of acute renal infection is not established or patients present with recurrent episodes of infection, renal imaging is indicated because of an increased possibility of stones, obstruction, Chapter 95 Computed Tomography of Urogenital Tract: Techniques and Normal Appearances 1535 abscess, or a congenital anomaly. In patients with suspected ovarian cancer, pelvic inflammatory disease, endometriosis, diverticulitis or rectal cancer 200 mL water soluble contrast enema may be ideal to delineate disease extent. This protocol optimizes paren chymal enhancement as well as vascular opacification for lymph nodes metastasis detection. Measurement of the volume of an organ can be readily calculated by tracing the organ of interest with an electronic computer cursor and summating the surface area measurements obtained on the individual scans. This area is then multiplied by the slice thickness to determine the segmental volume. The total volume of the organ to be measured is com-puted by the addition of all segmental volumes. Because of the small diameter of the vessels of interest and their parallel or near parallel course to the imaging plane thin nominal section thickness of 1. Conventionally, the region between the superior mesenteric artery and lower border of L3 is chosen so as to include sites of origin of accessory renal arteries. Delay time is determined through prior time density curves of dynamic scanning and patient is instructed for breath holding. Superimposition of vessels may interfere but this may be overcome by generating multiple images in different projections which can be rotated about an axis to visualize three dimensional vascular relationships. The true lumen opacified with contrast and the non-opacified false lumen are clearly seen. A volumetric dataset is acquired, the images are computer rendered to generate 3D images. Virtual cystoscopy may prove to be useful for detecting bladder lesions greater than 5 mm. Virtual endoscopic techniques may provide ureteral "flythroughs" allowing the observer to have a ureteroscopic view point of the urinary tract. The interactive navigation and interpretation of 3D virtual reality imaging is performed. Second, virtual cystoscopy can allow the operator to navigate the muscosal surface of the bladder in various projections. It is not associated with the risk of local infection, bladder perforation stricture or scarring. In conclusion for every practicing radiologist an adequate knowledge of 3D anatomy of the urogenital system, a clear understanding of its physiology and that of contrast media is required. Improvements in scanner technology, coupled with affordable and powerful computer graphic systems have resulted in superb image generation and visualization tools for the radiologist and the clinician. Although the advanced visualization techniques do not actually create new anatomic data above and beyond the source cross-sections, using these tools to display the data in new ways that more closely simulate natural 3D scenes may create additional new visual information about the patient. The current challenge is to prove that the additional effort and expense are justified by improving patient care through more accurate diagnosis, improved patient outcome and improved communication with the referring physician. Sixteen row multislice computed tomography: Basic concepts, protocols and enhanced clinical applications. Assessment of the clinical utility of rim and comet tail signs in differentiating 27. Current status of multidetector computed tomography urography in imaging of the urinary tract. The high spatial resolution, intrinsic tissue contrast, short scan time, elimination of motion artifacts and more extensive coverage of abdomen and pelvis provide better detection and characterization of anatomy and pathology of the urogenital tract. Spectroscopic studies especially in prostate are useful for detection and differentiation of malignant from benign pathologies by noninvasively providing the chemical assay of the assessed tissue. Malignant lymph node detection also has improved significantly with new contrast agents, such as iron-based particles. Small tumor detection may be aided by fat suppression combined with gadolinium administration. Usually both T1 and T2-weighted sequences are performed in the axial plane in combination with sections in coronal and sagittal planes. It is primarily used as an additional tool of renal imaging in a number of situations. It can be used for evaluation and characterization of renal masses and fluid collections. In addition, in- and opposed-phase breath hold T1-weighted gradient echo sequences provide an excellent anatomic detail of the retroperitoneum and detection of intracellular lipid. Cortical enhancement which primarily reflects renal perfusion is seen earliest, followed by medullary enhancement which reflects mainly glomerular filtration rate, and lastly the enhancement of the collecting system that represents the functional status of the renal tubules. It is based on the principle that simple fluids, such as urine have very long T2-relaxation time and heavily T2-weighted pulse sequence generate images with high signal intensity from static fluid in the collecting whereas lower signal intensity from parenchymal tissue is suppressed. This is useful in patients where use of ionizing radiation or iodinated contrast material is to be avoided. However, this technique does not provide information about the renal function and may not visualize a non-dilated system. Low doses of a diuretic agent can be administered before the examination for better filling of the pelvicalyceal system. T1-weighted images show good cortico-medullary differentiation with cortex being usually higher in signal intensity compared to the medulla. The sinus fat at the renal hilum appears bright on both T1- and T2-weighted images. The renal arteries, renal veins, aorta and inferior vena cava are seen as tubular structures that are free from intraluminal signal, although flow related artifacts may cause high signal in these vessels. The kidneys show maximal cortical enhancement in arterial phase with good corticomedullary differentiation (A). This technique is independent of flow related phenomenon, assesses the true lumen of vessels and has high spatial resolution. However, these techniques have multiple limitations, such as signal loss due to turbulence at the stenosis, over estimation of stenosis due to turbulent jets leading to signal loss, bright signal of fresh thrombus, motion artifacts, nonvisualization of small vessels and poor quality due to slow flow. Both the main arterial trunks and segmental branches are outlined normal left renal vein lying anterior to the left renal artery (B). Its multiplanar capability allows better visualization of tumors located at the bladder base and dome. It is important to differentiate the normal low intensity of the bladder wall from the chemical shift artifact caused by different resonant frequency of the hydrogen nuclei of the urine and fat. On axial images, it is seen as a dark band along the lateral wall of one side of the bladder, and a bright stripe along the opposite wall. On sagittal or coronal images the artifact is seen along the base and dome of the bladder. Dynamic contrast enhanced imaging using a fast gradient sequence allows differentiation of tumors from uninvolved bladder wall in most cases if the imaging is completed within 90 seconds as the normal bladder wall enhances later. They can also show invasion of the bladder wall while body coil can only show gross extravesical extension of tumours.

Loss of corticomedullary differentiation on T1W spin echo sequences is a sensitive indicator of parenchymal Radionulceotide Imaging Scintigraphy provides imaging based diagnostic information on renal structure and function acute asthmatic bronchitis icd 9 buy ventolin 100 mcg with mastercard. Radionucleotide agents are excreted by kidneys; hence asthma bronchioles buy 100 mcg ventolin amex, they should be judiciously employed in patients with renal failure asthma symptoms when to go to hospital buy discount ventolin on line. The most important risk factor is pre-existing renal insufficiency (serum creatinine >1 asthma breathing test discount ventolin 100 mcg overnight delivery. Adequate hydration asthma 1 year old ventolin 100 mcg line, dose reduction and use of non-ionic contrast media are recommended as preventive measures asthmatic bronchitis lung cancer purchase ventolin without prescription. Infections, cystic renal diseases, obstructions, renal vascular diseases and tumors are not included here, as they are covered in other chapters in this book. When obstruction is ruled out a similar picture of enlarged smooth kidneys with normal or effaced collecting system is seen that indicates parenchymal disease of recent origin, which is possibly reversible. As tubules are filled with cellular infiltrates, contrast leaks into the interstitium through the damaged basement membrane; hence, faint or nonopacification of pelvicalyceal system occurs. Both kidneys are involved either diffusely or in patchy distribution; in both instances peripheral renal cortex is spared as it is supplied by the preserved capsular vessels. Other causes include severe trauma with shock, sepsis, transfusion reaction, severe dehydration, burns, peritonitis and toxins. Although large numbers of conditions are associated with acute cortical necrosis, the pathophysiology unfortunately remains unclear. For those surviving the early phase, smooth renal shrinkage occurs over several months. Radiographically, distinctive tram like or egg shell calcification of cortex may be seen which start appearing as early as 24 days after the onset of disease. Calcification of cortex causes dense cortical echoes with distal acoustic shadowing. The three diagnostic features are (a) enhancement of the medulla, (b) nonenhancement of the renal cortex, and (c) lack of excretion of contrast medium into the collecting system. Usually, markedly large kidneys are seen; however, sometimes asymmetrical renal involvement or focal renal mass may be seen. Imaging Features In leukemic infiltration of kidney, the nephrogram is faint and the collecting system is attenuated. Pelvicalyceal system is often filled with blood clots or uric acid stones which appear as filling defects. Amyloidosis Amyloidosis is a diverse group of diseases that have extracellular deposition of an insoluble fibrillar proteinaceous substance with a beta sheath configuration. Amyloidosis can be classified as follows:32 zz Primary Amyloidosis: Without pre-existing or coexisting disease. Imaging Features Bilateral renomegaly with diminished to normal opacification of collecting system is seen on urography. Enhanced uptake of Gallium citrate in the kidneys on renal scintigraphy is also reported. Calcification of renal papillae may occur in analgesic induced Chapter 108 Renal Parenchymal Disease and Renal Failure 1723 Heredofamilial amyloidosis associated with familial mediterranean fever. Older men are more affected than women, 33 usually presenting with nonspecific symptoms like weight loss, fatigue and weakness. Isolated involvement of the renal pelvis, ureter bladder, urethra, prostate seminal vesicle, and retroperitoneum can occur. Nausea, vomiting, anorexia, weight loss and progressive weakness are the presenting features. Nephrocalcinosis resulting from hypercalcemia, uric acid calculi, renal infections and amyloidosis may further complicate the illness. Imaging Features Urography shows enlarged smooth kidneys with faint opacification indicating impaired renal function. Injection of iodinated contrast media is hazardous in patients of multiple myeloma as it precipitates myeloma proteins in the renal tubules. Decrease in size occurs with progression of disease process, smooth outline is, however, maintained. Nephrogram is diminished with variable excretion into normal pelvicalyceal system. Rapid deterioration in renal function or sudden onset nephrotic syndrome indicates renal vein thrombosis, a complication of amyloidosis. Bilateral increased delayed uptake of Gallium 67 when other causes of abnormal gallium activity are excluded. Patient presents with hemoglobinuria, iron deficiency anemia and venous thrombosis. Paramagnetic effects of hemosiderin results in markedly reduced signal in the cortex in both T1W and T2W images but it is more pronounced on T2W sequences. Similar imaging features are seen in intravascular hemolysis like in malfunctioning prosthetic valves, sickle cell anemia, hereditary spherocytosis and thalassemia. Interesting radiological appearance of calcification or ossification in the amyloid deposits may be seen. Other causes for calcification of pelvicalyceal system are tuberculosis, leukoplakia primary carcinoma of renal pelvis and renal calculus. Chronic Renal Parenchymal Disease In contrast to the capacity of kidney to regain back its function following acute renal insult, renal injury of more prolonged nature often leads to progressive and irreversible loss of nephrons. Such reduction in renal mass subsequently results in bilaterally small smooth kidneys. Radiological features, like those in acute renal parenchymal disease are overlapping in most of the causes of chronic renal parenchymal disease. However, some conditions show interesting radiological appearances and are discussed here. The various causes of bilateral small smooth kidneys are listed in Flow chart 5, the conditions leading to morphologically small, unilateral Multiple Myeloma Multiple myeloma is a plasma cell disorder which originates in the bone marrow and is characterized by involvement of the skeleton at multiple sites. Note made of simple cortical renal cyst in left upper pole (white arrow) kidneys are also cited. Renal Papillary Necrosis Necroses of the renal papillae not only have many causes but also many radiological forms. Parenchymal diseases affecting the papillae and calyces are diagnosed on urography. In mild cases the kidney size and function are normal, and the abnormality is limited to the papillae only. In advanced disease, there is global shrinkage of kidney with impaired renal function. Other causes are diabetes, sickle cell nephropathy, obstruction with infection, renal vein thrombosis, dehydration and prolonged hypotension. In early papillary necrosis ischemia occurs in the renal papillae due to compression of the medullary vessels by inflammatory changes in the interstitium. If the phase of temporary spasm passes, normal circulation is restored and the involved tissues may recover. However, if ischemia continues and perfusion is not restored, irreversible coagulation necrosis, tubular fibrosis and lobar infarcts result. Few amputated calyces are also seen Urographic findings during this period of early ischemic change are usually normal. Detachment of necrotic papillae starts in the central part of the calix, opening into a round or oval cavity. Papillary: Detachment of necrotic papillae usually begins in the region of the caliceal fornices, and the resulting defect is triangular in shape also termed as lobster claw appearance. In situ: When papillae fail to separate (necrosis in situ) calyces appear normal, they later calcify to give appearance of nephrocalcinosis. In the healing phase, the papilla may epithelialize, and its tip takes a blunted appearance. In addition, shrinkage of the kidney may occur with reduction of parenchymal thickness. Moreover, the loss of renal cortex is associated hypertrophy of the renal columns resulting in a typical irregular wavy renal outline. Their differentiation with other cystic lesions in the renal medullae should be done (like hydronephrosis, congenital megacalices, parapelvic cysts, and caliceal diverticula). Imaging Features Kidneys are severely shrunken in advanced stage, but maintain their smooth outline. Hyperechogenicity due to nephrocalcinosis is present which is due to chronic glomerulonephritis. The disease courses over many years but it rarely leads to kidney failure on its own. Malignant nephrosclerosis, however, progresses very rapidly and damages the arteries. These damaged arteries are unable to provide enough oxygen to the kidney tissues, resulting in kidney failure. The spectrum consists of secondary hyperparathyroidism along with rickets, osteomalacia, osteosclerosis, and osteoporosis. Inability of the kidney to adequately excrete phosphate, leads to hyperphosphatemia and increased osteoclastic activity. It can be categorized by resorption of bone at subperiosteal, cortical, subchondral, trabecular, endosteal, and subligamentous locations. Radiographic appearance of subperiosteal resorption has been described as a lacelike irregularity of the normal cortical margin, which may progress to areas of scalloping and spiculation. The earliest involvement is often seen along the radial aspects of the middle phalanges of the index and middle fingers, beginning in the proximal metaphyseal region. This is well seen in the skull, described as a granular salt-and-pepper appearance, with loss of distinction between the inner and outer tables. Osteosclerosis has a strong predilection for the axial skeleton, where cancellous bone predominates over cortical bone. In the vertebral bodies, bandlike areas of sclerosis zz Imaging Features Kidneys are small and smooth in benign nephrosclerosis; occasionally shallow infarcts can be seen. Normal nephrographic opacification, and excretion into pelvicalyceal system is seen on urography. On ultrasonography, increased central sinus echogenicity due to fat deposition may be seen. Subcapsular and perirenal hemorrhages may be detected as hypoechoic or anechoic fluid collections. Subchondral resorption of bone is seen at the pubis symphysis, ischial tuberosities, and sacroiliac joint (arrow) involving the superior and inferior end plates with intervening normal osseous density are classically seen, which resemble the stripes on rugby jerseys called as rugger jersey spine. Changes of rickets can be seen in children with a general delay in bone age, bowing of long bones, scoliosis, diffuse concave impressions at multiple vertebral end plates, basilar invagination of the skull, "triradiate pelvis" deformity and rachitic rosary. In children, epiphyseal displacement (slipped epiphysis) in children is also seen. Metastatic soft tissue and vascular calcification can be seen in ocular tissues, arteries, subcutaneous and periarticular soft tissues, and viscera. Despite these achievements radiological imaging still has limitations in evaluation of renal parenchymal disease and renal failure. Radiological imaging techniques are rapidly expanding and are expected to grow even further. The future possibly holds improved methods to readily identify the causes of reversible acute renal failure and plan treatment strategies to combat chronic renal failure. The combination of better diagnostic methods and management strategies will lead to improved quality of life in patients with renal failure. Clinical practice guidelines for chronic kidney diseases: Evaluation, classification, stratification. Intrarenal arterial Doppler sonography in patients with non-obstructive renal disease: Correlation of resistive index with biopsy findings. Renal Safety of Gadolinium Based Contrast Media in Patients with Chronic Renal Insufficiency. Metanalysis of relative nephrotoxicity of high and low osmolality Iodinated Contrast Media Radiology. Renal function impairment of the transplant kidney can be secondary to parenchymal abnormality or due to surgical complications. Depending upon the clinical findings, appropriate diagnostic studies are carried out. Renal biopsy remains the definitive way to diagnose the parenchymal abnormalities. To diagnose this early, there is a routine policy of clinical surveillance complemented with laboratory tests and imaging. It is usually self-limiting with renal function returning to normal within few days to weeks. In cadaveric renal transplants, an aortic patch (Carrel patch) is commonly removed with main renal artery. The current preferred method of re-establishing continuity of urinary tract is by creation of ureteroneocystostomy (commonly by using a submucosal tunnel to decrease the incidence of vesicoureteric reflux). Early complications appear in the first few weeks and are generally due to surgical difficulties. Late complications appear some weeks later and are normally due to medical problems (usually due to immunosuppression or due to drug toxicity). Early complications include acute rejection, acute tubular necrosis, hematoma, pyelonephritis, abscess, urinoma, acute ureteral obstruction and vascular complications. Late complications include chronic rejection, lymphocele, cyst Rejection Acute rejection remains one of the most serious and common complications. Virtually every patient experiences some degree of rejection, and differentiating rejection from other causes of graft dysfunction remains a challenging clinical problem.

Fine needle aspiration cytology from splenic and lymph node involvement has a high sensitivity (87 asthma quality of life questionnaire generic 100 mcg ventolin with mastercard. Diagnostic yield from bowel lesions has been reported to be low due to desmoplastic reaction secondary to chronic hypertrophic lesions asthma symptoms after pneumonia purchase ventolin visa. Nuclear imaging techniques do not help distinguish between the different causes of sepsis asthma upper or lower airway obstruction purchase ventolin 100 mcg visa, but they do help identify a focus of interest asthma definition 4g order ventolin mastercard. Further imaging of the area in question asthmatic bronchitis on chest x-ray buy discount ventolin on line, along with additional tissue sampling asthma symptoms fatigue 100mcg ventolin fast delivery, can then be performed to aid in diagnosis. Symptoms and investigative findings in 145 patients with tuberculous peritonitis diagnosed by peritoneoscopy and biopsy over a 5 year period. Further invasive and costly procedures are required for obtaining tissue for histopathological examination. Diagnosis based on radiology is rapid and less expensive, 1210 Section 3 Gastrointestinal and Hepatobiliary Imaging 6. Diagnosis of abdominal tuberculosis: sonographic findings in patients with early disease. Idiopathic sclerosing encapsulating peritonitis (or abdominal cocoon) A report of 5 cases. Tuberculous abdominal lymphadenopathy causing reversible renovascular hypertension. Patterns of contrast enhancement of tuberculous lymph nodes demonstrated by computed tomography. Radiological manifestations of splenic tuberculosis: 23 patient case series from India. Superior mesenteric artery blood flow in patients with small bowel diseases: evaluation with duplex doppler sonography. Extrapulmonary tuberculosis in patients with human immunovirus deficiency virus infection. Ulcerative colitis is a superficial inflammatory disease characterized by symmetric, uniform and contiguous process that usually involves the rectum, extending proximally until the entire colon is affected, producing a pancolitis. The disease is confined to colon spreading in a contiguous manner from the rectum proximally, and terminal ileum may be affected only when ascending colon and cecum are involved (backwash ileitis). The small intestine is involved in 80% of cases, most commonly at the terminal ileum. In the appropriate clinical settings, these modalities help confirm the diagnosis, localize lesions, assess their extent, severity and activity, identify the presence of extraintestinal complications and monitor the response to therapy. Barium studies though provide superb visualization of mucosa, are limited in their capacity to demonstrate the transmural and extramural extent of disease and extraintestinal complications. Computed tomography perfusion studies can demonstrate actively inflamed segments of bowel. Its attributes include high soft tissue contrast, multiplanar capabilities and the use of nonionizing radiation. The greatest advantage is its ability to differentiate active inflammation from fibrosis. For colonic evaluations, T1-weighted positive signal is referred to as "bright lumen" imaging which can be performed using mixture of water and gadolinium per rectally. The "dark lumen" technique produces a dark intraluminal contrast on T1W1 after application of rectal water enema to contrast with a bright bowel wall which is achieved by intravenous contrast agent. High resolution sonography has a good sensitivity in detecting bowel inflammation. It simultaneously detects inflammation and disease activity in large and small bowel. Colonic shortening is caused by thickening and contraction of muscularis mucosae without actual fibrosis. Barium enteroclysis particularly double contrast (barium and air) enteroclysis is superior for evaluation of early lesion. The earliest pathological changes are in the form of hyperplasia of the lymphoid tissue and obstructive lymphedema in the submucosa which may not be manifested as on barium studies. These ulcers can only be wellappreciated on double contrast (barium and air) enteroclysis. Pathologically, these represent shallow mucosal erosions on the surface of hyperplastic lymphoid follicles in the lamina propria surrounded by a small halo of edema. The narrowing is usually eccentric along the mesenteric border which is associated with thickening, sclerosis, and retraction of the adjacent mesentery. In the fibrostenotic subtype transmural fibrosis manifests as homogeneous attenuation of bowel wall. Bowel wall thickening appears as increased signal on T2-weighted images which on contrast-enhanced T1-weighted sequences shows enhancement. In addition, fibrofatty proliferation of mesentery and enlarged mesenteric lymph nodes which are of low signal intensity can also be present. High resolution sonography may show bowel thickening with mural stratification and mesenteric lymphadenopathy. On Doppler examination hypervascularity of bowel wall can be seen which parallels the activity of inflammatory disease. These lesions represent shallow erosion on the surface of hyperplastic lymphoid follicles in the lamina propria. In fact, the entire colon is involved, but the distribution of gas in the transverse colon is a result of anatomy and gravity, since the plain X-ray abdomen is taken in supine position. Concomitant distension of the small bowel and less frequently, the stomach, has also been reported. It seems to result from a combination of several factors, such as increased release of soluble inflammatory mediators enhancing nitric oxide generation and activation of nerve endings of mucosal afferent fibres. Nitric oxide generation leads to muscle relaxation and colonic dilatation, whereas the activation of sensory fibres elicit inhibitory reflexes lead to distension of stomach and small bowel. Imaging modalities can be used to diagnose these complications and for percutaneous drainage of these abscesses. Dermatologic Erythema nodosum, vitiligo, dermatitis Hematologic Anemia, thromboembolic disease, etc. Histopathological examinations are inconclusive in majority causing a great diagnostic dilemma. Mesenteric ischemia may be acute or chronic depending on the onset and clinical presentation. Acute mesenteric ischemia may be caused by either arterial or venous occlusion, although arterial occlusion is far more common. Thromboembolic arterial occlusion is the most common cause of acute mesenteric ischemia. Nonocclusive mesenteric ischemia is also acute ischemia and is usually segmental involving the splenic flexure or the sigmoid colon representing the "watershed" zones. Most cases of colonic ischemia occur as a result of sudden drop in blood flow because of low flow states. Chronic mesenteric ischemia results from atherosclerosis of the mesenteric arteries. Computed tomography perfusion scanning is able to detect early changes in perfusion in ischemic segments before irreversible damage has occurred. Additional abnormal findings consist of bowel wall thickening and increase in signal intensity from compromised bowel on T2W1. The diagnostic sensitivity of angiography is very high in assessing arterial occlusion. Percutaneous transluminal angioplasty with or without stent placement can be done. The bowel wall may demonstrate low attenuation reflecting submucosal edema and inflammation or high attenuation due to submucosal hemorrhage. After the intravenous administration of contrast material affected loops may demonstrate decreased enhancement compared with normal loops due to compromised blood flow. In some patients, the affected loops may demonstrate increased enhancement due to hyperemia. Pneumatosis with or without air in the mesenteric vessels or portal vein in an ominous finding in patients, suggests necrosis. Computed tomography is more sensitive than plain radiography in detection of pneumatosis and sometimes allows identification of the cause. Most cases of transient colonic ischemia due to hypovolemia are treated conservatively. However, some patients go on to develop scarring and stricture in the involved segment. In addition to bowel wall thickening, ischemic small bowel may demonstrate luminal dilatation and mesenteric stranding. In patients with acute mesenteric ischemia, the portion of the intestine affected depends on the cause of the ischemia and the availability of collateral vessels. In low-flow states causing mesenteric ischemia, the mesenteric arteries may appear narrowed with limited opacification of branches due to hypovolemia and spasm. In contrast to acute ischemia, most cases of chronic mesenteric ischemia result from atherosclerosis of the mesenteric arteries. Computed tomography can detect calcified plaque in the aorta and mesenteric arteries. Unlike in patients with acute mesenteric ischemia, the small intestine usually appears normal in patients with chronic mesenteric ischemia. Barium studies should not be performed in cases of suspected acute mesenteric ischemia. In clinically unsuspected cases, barium findings include bowel dilatation, thumb printing, thickened folds, submucosal edema and ulceration. Appendicitis Acute appendicitis occurs when the appendiceal lumen becomes occluded, resulting in an accumulation of fluid, appendiceal dilatation, inflammation, ischemia, and eventually perforation with possible abscess formation. The presence of an appendicolith along with pericecal inflammation or a mass is considered diagnostic for appendicitis. Focal cecal apical thickening occurs when appendiceal inflammation spreads contiguously to involve the cecal tip. The "arrowhead sign" is also caused by contiguous spread of inflammation from the appendix to the cecum, resulting in a triangular space between the thickened walls of the appendix. A cecal bar occurs when a curved soft-tissue bar is interposed between the cecal lumen and appendicolith. A hallmark of acute appendicitis is a varying degree of inflammatory thickening in the fat surrounding the diseased appendix with stranding of the pericecal fat. Perforation is a potential complication of appendicitis and appears as small pockets of extraluminal air. An appendiceal abscess appears as a pericecal fluid collection that may contain air or necrotic debris. Periappendiceal fluid and increased vascularity of appendix are other supportive evidences in diagnosis of appendicitis. Rarely, a central high-attenuation "dot" can be identified within the inflammed appendage: this finding corresponds to the thrombosed vein. The key to distinguishing diverticulitis from other inflammatory conditions that affect the colon is the presence of diverticula in the involved segment. The presence of fluid in the root of the sigmoid mesentery and engorgement of adjacent sigmoid mesenteric vasculature favors the diagnosis of diverticulitis. Radiation Colitis Patients receiving more than 3,000 cGy of radiation therapy to the pelvis, experience acute proctitis. Acute radiation injury to the small intestine and colon occurs during or within a few weeks of radiation exposure. The sigmoid colon and rectum are most commonly affected because radiation therapy is often given for pelvic disease. Barium exam is an excellent method to evaluate the site and extent of involvement, even though the findings are nonspecific. Pseudomembranous Colitis Pseudomembranous colitis results from toxins produced by an overgrowth of the organizm Clostridium difficile. In mild cases, a low pressure barium enema may be performed which shows pseudomembranes as elevated plaques. In addition to wall thickening the colon is often dilated, probably due to the transmural inflammation. The pericolic stranding in pseudomembranous colitis is often disproportionately mild relative to the marked colonic wall thickening, since the condition predominantly affects the mucosa and submucosa. When haustral folds are significantly thickened, they can appear as broad transverse bands that may trap oral contrast material. The accordion sign is very suggestive of pseudomembranous colitis but typically occurs only in severe cases and is therefore, not a sensitive indicator. Amebic Colitis Entameba histolytica is a simple protozoan which invades the mucosa and causes cell destruction. The radiological findings in amebiasis are as varied as its clinical presentation. Concentric narrowing resulting in coned cecum with shaggy contour may be seen with disease progression.

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