Biomedical subjects

Gary M Israel

Publications and source records attributed to Gary M Israel.

25 records · Page 2Linked to original sources

PubMed2003

Follow-up CT of moderately complex cystic lesions of the kidney (Bosniak category IIF).

OBJECTIVE: The purpose of this study is to show the use of follow-up CT studies in the management of moderately complex cystic lesions of the kidney (Bosniak category IIF). MATERIALS AND METHODS: The CT scans of 42 moderately complex cystic renal masses (Bosniak category IIF) with follow-up examinations for 2 years or greater or with pathology correlation (n = 3) were retrospectively analyzed by the authors in consensus. The complexity of each lesion was assessed on the basis of the number and appearance of the septa, wall thickness, interface with the kidney parenchyma, presence and amount of calcification, and contrast enhancement characteristics. Lesion size was measured in two dimensions. Follow-up examinations were evaluated for any interval change. RESULTS: The average size of the lesions was 3.9 x 3.6 cm, and the average follow-up time was 5.8 years (range, 2 years-18 years 4 months; median, 5.0 years). Eighteen lesions had fewer than five septa, 16 lesions had between five and nine septa, and eight lesions had more than nine septa. In 39 lesions, the wall or septa or both were slightly thickened, and in a single lesion, the wall and septa were hairline thin. The two remaining lesions were of uniformly high attenuation and completely intrarenal. Forty-one lesions had a sharp interface with the kidney, whereas one had an indistinct interface. Twenty lesions contained calcium. Enhancement was not shown in any lesions except for minimal enhancement of smooth walls or septa of some lesions. Follow-up examinations showed that three lesions had developed more calcification, one lesion had increased in overall size but appeared less complex, and three lesions had decreased in size. In addition, two lesions had become more complex and developed thicker septa, and these lesions proved to be cystic neoplasms. CONCLUSION: Follow-up CT studies are an effective way of managing patients with moderately complex cystic lesions of the kidney (Bosniak category IIF) because the absence of change supports benignity and progression indicates neoplasm.

Adult↗

PubMed2002

Computed tomography diagnosis utilizing compressed image data: an ROC analysis using acute appendicitis as a model.

Using receiver-operating characteristic (ROC) methodology, the ability to diagnose acute appendicitis with computed tomography (CT) images displayed at varying levels of lossy compression was evaluated. Nine sequential images over the ileocecal region were obtained from 53 consecutive patients with right lower quadrant pain who were clinically suspected to have acute appendicitis. Thirty were proven surgically to have acute appendicitis, alternative diagnoses confirmed in 23. The image sets were subjected to a lossy wavelet-based compression algorithm "Embedded Predictive Wavelet Image Coder" (EPWIC). Compression levels were: none, 8:1, 16:1, and 24:1, resulting in 4 sets of images per patient. Image sets were randomized and evaluated separately by 4 body radiologists on a 1,024 x 768-pixel SVGA color PC monitor in 512 x 512 format. The readers were aware of the clinical suspicion of appendicitis but were unaware of the positive fraction of cases. Individual and combined reader ROC and c2 analyses of sensitivity, specificity, and accuracy were determined. For all readers, sensitivity decreases at 16:1 and 24:1 levels (P <0.01, P <0.001, respectively). Accuracy decreased at 24:1 levels (P <0.01). Specificity was unaffected. By ROC analysis there was statistically significantly decreased area under the curve at 24:1 levels (P <0.02) as compared with uncompressed images. Finite levels of lossy wavelet compression may be applied to CT images without compromising diagnostic performance.

Acute Disease↗

PubMed2002

Comprehensive MR imaging in the preoperative evaluation of living donor candidates for laparoscopic nephrectomy: initial experience.

PURPOSE: To evaluate the accuracy of magnetic resonance (MR) imaging in the preoperative evaluation of potential living renal donors who are candidates for laparoscopic nephrectomy. MATERIALS AND METHODS: Twenty-eight donor candidates who underwent subsequent laparoscopic nephrectomy were examined by using a torso phased-array coil at 1.5 T. Gadolinium-enhanced MR angiograms, MR venograms, and MR urograms were obtained in all patients by using an interpolated three-dimensional T1-weighted spoiled gradient-echo sequence (3.4-6.8/1.2-2.3 [repetition time msec/echo time msec], 25 degrees -40 degrees flip angle). Interpretation of the MR images was used to assess the arterial, venous, and ureteral anatomy, as well as parenchymal masses and scarring, and findings were compared with the surgical findings in all patients. Statistical evaluation was performed, with the surgical findings as the reference standard. RESULTS: At MR imaging, 31 of 32 renal arteries and one of three early-branching arteries were identified correctly. The correct venous anatomy was identified in 23 of 28 patients, including a single left renal vein anterior to the aorta (n = 16), retroaortic left renal vein (n = 2), circumaortic left renal vein (n = 2), and single right renal vein (n = 3). A single collecting system in all harvested kidneys was identified correctly with MR urography. Overall, MR imaging correctly depicted vascular, ureteral, and parenchymal anatomy in 21 of 28 patients. Twenty-seven of 28 patients underwent successful laparoscopic donor nephrectomy on the basis of the MR findings. One procedure was converted to open nephrectomy on the basis of complex venous anatomy not prospectively identified on the MR images. The sensitivity and positive predictive value of MR imaging in correctly determining the combined vascular, ureteral, and parenchymal anatomy in the harvested kidney were 75% (21 of 28) and 95% (21 of 22), respectively. CONCLUSION: Comprehensive gadolinium-enhanced MR imaging can depict the vascular anatomy, collecting system, and renal parenchyma preoperatively in patients who are candidates for laparoscopic living-donor nephrectomy.

Adult↗

PubMed2002

CT findings in acute gangrenous cholecystitis.

OBJECTIVE: The purpose of this study was to determine the CT findings in acute gangrenous cholecystitis. MATERIALS AND METHODS: Four observers retrospectively reviewed CT scans in 75 patients (23 with acute gangrenous cholecystitis, 25 with acute non-gangrenous cholecystitis, and 27 without cholecystitis). The following findings were evaluated: distention, mural thickening, wall enhancement, irregular wall, wall striation, intraluminal membranes, pericholecystic inflammation, gallstones, pericholecystic fluid, enhancement of liver parenchyma, pericholecystic abscess, and gas in the wall or lumen. Sensitivity and specificity of CT for gangrenous cholecystitis and for each finding were calculated. Two reviewers in consensus measured gallbladder dimension and wall thickness. Logistic regression models were used to predict gangrenous versus non-gangrenous cholecystitis. RESULTS: Sensitivity, specificity, and accuracy of CT for acute cholecystitis were 91.7%, 99.1%, and 94.3%, respectively, and for acute gangrenous cholecystitis were 29.3%, 96.0%, and 64.1%, respectively. Findings with the highest specificity for gangrenous cholecystitis were gas in the wall or lumen (100%), intraluminal membranes (99.5%), irregular or absent wall (97.6%), and abscess (96.6%). The difference between the mean gallbladder wall thickness and the short-axis dimension for the two groups with cholecystitis was statistically significant. In three patients with gangrenous cholecystitis, no mural enhancement was seen. Pericholecystic fluid also achieved statistical significance for the diagnosis of gangrene. Multivariate logistic regression analysis showed that the overall accuracy of CT for gangrenous cholecystitis was 86.7%. CONCLUSION: CT findings most specific for acute gangrenous cholecystitis are gas in the wall or lumen, intraluminal membranes, irregular wall, and pericholecystic abscess. Gangrenous cholecystitis is associated with a lack of mural enhancement, pericholecystic fluid, and a greater degree of gallbladder distention and wall thickening.

Acute Disease↗

PubMed2002

CT differentiation of large exophytic renal angiomyolipomas and perirenal liposarcomas.

OBJECTIVE: The purpose of our study was to describe the imaging findings and CT characteristics that lead to accurate distinction of large exophytic renal angiomyolipomas from retroperitoneal perirenal liposarcomas, which at times can be confused on imaging studies and even at pathologic examination. MATERIALS AND METHODS: We retrospectively analyzed CT images of 15 large exophytic renal angiomyolipomas and 12 well-differentiated perirenal liposarcomas. Pathologic correlation was available for six of 15 angiomyolipomas and all of the liposarcomas. All examinations were evaluated for lesion size, renal parenchymal defect, enlarged vessels, kidney displacement, lesion encapsulation or margination, associated hemorrhage, and additional angiomyolipomas. The records of patients with tuberous sclerosis or the forme fruste of that condition were excluded from the study. RESULTS: The average size of the angiomyolipomas was 14 x 10 cm. They showed a renal parenchymal defect (n = 15), enlarged vessels (n = 12), renal displacement (n = 14), good margination without a distinct capsule (n = 14), hemorrhage (n = 1), and additional (one or two) angiomyolipomas (n = 4). The average size of the liposarcomas was 18 x 11.6 cm. They showed enlarged vessels (n = 3), renal displacement (n = 11), and encapsulation (n = 4); none showed a renal parenchymal defect, hemorrhage, or associated angiomyolipomas. CONCLUSION: Although large exophytic angiomyolipomas and well-differentiated retroperitoneal liposarcomas may have similar appearances on imaging, careful evaluation for a defect in the renal parenchyma combined with the presence of enlarged vessels in angiomyolipomas should enable accurate differentiation in almost all cases. Achieving an accurate diagnosis can have a significant impact on patient treatment.

Adult↗

PubMedDate not supplied

Masses and pseudomasses of the kidney: imaging spectrum on MR.

MR imaging is useful in differentiating and characterizing renal masses. A careful evaluation of the signal characteristics and morphology of a renal mass combined with the ancillary imaging findings and patient history should assist the radiologist in making the proper diagnosis or recommending the appropriate treatment in most cases. This pictorial essay demonstrates the typical MR imaging features of common renal masses including renal cell carcinoma (RCC), oncocytoma, angiomyolipoma, metastases, transitional cell carcinoma (TCC), lymphoma, and arteriovenous malformation (AVM), and highlights several potential diagnostic pitfalls in making the proper diagnosis.

Adenoma, Oxyphilic↗

PubMedDate not supplied

CT and MR imaging of complications of partial nephrectomy.

The standard treatment for renal cell carcinoma for many years was radical nephrectomy, but in the past decade there has been a trend toward elective nephron-sparing surgery. Initially, partial nephrectomy was performed with an open surgical approach; more recently and with increasing frequency, a laparoscopic approach has been used in selected cases. Nephron-sparing surgery with either approach is more complex than is traditional radical nephrectomy and more frequently results in complications. The possible complications of partial nephrectomy include vascular, collecting system, and technical complications as well as recurrent tumor and infection. For prompt diagnosis and appropriate management of these complications, radiologists must be familiar with normal and abnormal features in the postoperative appearance of the kidney at computed tomography and magnetic resonance imaging.

Carcinoma, Renal Cell↗