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Biomedical subjects

Gary M Israel

Publications and source records attributed to Gary M Israel.

At least 19 recordsLinked to original sources
PubMed2006

Are T2-weighted images necessary in renal mass characterization?

OBJECTIVE: To determine what role T2-weighted images play in characterizing renal masses. METHODS: Forty-four pathologically proven renal masses (34 renal cell carcinomas, 8 oncocytomas, 1 metanephric adenoma, 1 angiomyolipoma without macroscopic fat) and 38 simple renal cysts were evaluated with T1- and T2-weighted images at 1.5T. Two independent and blinded readers initially characterized all masses using only the T1-weighed images (in- and opposed-phase chemical shift, unenhanced frequency-selective fat-suppressed, gadolinium-enhanced frequency-selective fat-suppressed and subtraction images) and placed each mass into one of three categories: nonsurgical, in need of follow-up, or surgical. The masses were then re-evaluated with the addition of the T2-weighted images. It was determined if the T2-weighted images changed the initial classification. RESULTS: Forty-three of the 44 (98%) pathologically proven renal masses were characterized as a surgical mass using only the T1-weighted images. The remaining renal mass (a renal cell carcinoma) was characterized as a mass in which follow-up exams would be suggested. Thirty-eight of 38 (100%) simple renal cysts were correctly characterized using only the T1-weighted images. The T2-weighted images did not change the initial interpretation of the T1-weighted images in any of the cases. CONCLUSION: The results of this study suggest that T2-weighted images are not necessary in the evaluation of all renal masses and are specifically not necessary in the differentiation of solid and cystic renal neoplasms from simple renal cysts.

Aged↗
PubMed2006

MRI of the kidney and urinary tract.

MRI of the kidney and urinary tract has evolved with advancements in MR technology combined with further radiologic experience. A combination of simple pulse sequences and the use of gadolinium (Gd) allow a comprehensive evaluation of the genitourinary system and facilitate the detection and accurate characterization of renal and urinary tract masses. In this review an MRI technique used to evaluate the kidneys and urinary tract is presented with an emphasis on the characterization of renal masses.

Contrast Media↗
PubMed2006

Hepatocellular carcinoma in the cirrhotic liver: gadolinium-enhanced 3D T1-weighted MR imaging as a stand-alone sequence for diagnosis.

PURPOSE: To retrospectively assess the usefulness of contrast material-enhanced T1-weighted magnetic resonance (MR) imaging alone and with T2-weighted MR imaging in the diagnosis of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: A waiver of informed consent and institutional review board approval for this retrospective study were granted. The study was HIPAA compliant. Twenty-eight men (mean age, 49 years; range, 23-70 years) and 10 women (mean age, 53 years; range, 42-72 years) with cirrhosis underwent T2-weighted and contrast-enhanced T1-weighted MR imaging at 1.5 T within 90 days of liver transplantation. Three readers reviewed the T1-weighted images alone and then the T2-weighted and T1-weighted images together. Lesion detection, characterization, and reader confidence levels were recorded. RESULTS: At liver explantation, 57 lesions were present in 18 patients: 19 HCCs, 33 dysplastic nodules, and five cysts. Contrast-enhanced T1-weighted imaging depicted 13 of 19 HCCs with an overall sensitivity of 68.4% (13 of 19) and specificity of 65.7% (23 of 35). The sensitivity and specificity for detection of dysplastic nodules (sensitivity, 9%; specificity, 68.4%) and HCCs (sensitivity, 68.4%; specificity, 65.7%) were nearly identical for T1-weighted images read alone or read with T2-weighted images. The only difference was the specificity for T1-weighted images read alone (65.7%) and read with T2-weighted images (62.9%). The addition of T2-weighted images altered the diagnosis in one of 90 (1.1%) cases and provided an increase in diagnostic confidence in four of 258 (1.6%) cases for independent readers and three of 90 (3.3%) cases at consensus reading. CONCLUSION: Contrast-enhanced T1-weighted imaging can be used as a stand-alone sequence for the diagnosis of HCC in patients with cirrhosis prior to liver transplantation.

Adult↗
PubMed2006

Isotropic 3D T2-weighted MR cholangiopancreatography with parallel imaging: feasibility study.

OBJECTIVE: The aim of this study was to compare the quality of images obtained with fast 3D T2-weighted turbo spin-echo (TSE) MR cholangiopancreatography (MRCP) sequences and 1-mm isotropic voxels with the quality of conventional 2D MRCP images. SUBJECTS AND METHODS: Thirty consecutively registered patients (14 women, 16 men; average age, 60.2 years; age range, 32-87 years) underwent imaging at 1.5 T with a 6-element body array coil. All imaging was performed with three MRCP techniques: free-breathing 3D T2-weighted TSE (TR/TE, 1,300/680; flip angle, 180 degrees; field of view, 250-300 mm; matrix size, 256 x 256; slice thickness, 1 mm; parallel acquisition technique factor, 2); breath-hold 3D T2-weighted TSE (same parameters as the free-breathing 3D technique); breath-hold coronal and oblique coronal thick-slab 2D TSE without parallel acquisition technique (2,800/1,100; flip angle, 150-180 degrees). Quantitative measures of image signal and contrast were evaluated by analysis of variance and paired Student's t tests. A 5-point scale (1, nondiagnostic, to 5, high diagnostic confidence) was used to compare the 3D and 2D data sets for image quality and definition of biliary and pancreatic ductal anatomic features. Friedman's nonparametric and Wilcoxon's rank sum tests were performed for statistical analysis of the qualitative assessments. RESULTS: Quantitative results showed free-breathing and breath-hold 3D TSE images had significantly higher relative signal intensity and contrast than 2D TSE images (p < 0.0001). The qualitative findings showed that both free-breathing and breath-hold 3D TSE techniques gave better delineation of biliary anatomy (p < 0.0001) than the 2D technique. The overall quality of 3D images was better than that of 2D images, and 3D imaging was better at depicting pancreatic ducts, although the difference did not reach statistical significance. CONCLUSION: Three-dimensional volumetric MRCP images are of superior quality and give better delineation of pancreaticobiliary anatomy than conventional 2D images and have the added advantage of multiplanar and postprocessing capabilities.

Adult↗
PubMed2005

How I do it: evaluating renal masses.

With modern computed tomography (CT) and magnetic resonance (MR) imaging equipment, the diagnosis of most renal masses is usually straightforward and accurate. The major question to be answered is whether the mass represents a surgical or nonsurgical lesion or, in some cases, if follow-up studies are necessary. This evaluation usually can be accomplished if a high-quality examination is performed, if the clinical history of the patient is kept in mind, if conditions that mimic a renal neoplasm are considered and excluded, and if there is an awareness of the potential pitfalls and limitations of CT and MR imaging. In this article, the authors present their technique in the performance of CT and MR imaging examinations, summarize their approach to the diagnosis of renal masses, review the imaging findings in these lesions, and stress the limitations in renal mass diagnosis.

Diagnosis, Differential↗
PubMed2005

The use of opposed-phase chemical shift MRI in the diagnosis of renal angiomyolipomas.

OBJECTIVE: The objective of our study was to determine the reliability of the location of the india ink artifact and signal loss on opposed-phase chemical shift MRI to differentiate angiomyolipomas from solid renal masses and from hemorrhagic-proteinaceous renal cysts. MATERIALS AND METHODS: Twenty-three angiomyolipomas, 24 hemorrhagic-proteinaceous cysts, and 23 solid renal masses (nonangiomyolipomas) were retrospectively evaluated at 1.5 T with chemical shift MRI using TEs of 2.1-2.7 msec (opposed phase) and 4.8-5.3 msec (in phase). Two independent observers reviewed the MR images for signal loss on opposed-phase images and for the presence or absence of india ink artifact. An angiomyolipoma was diagnosed if the india ink artifact was identified at the interface of the mass and the kidney or was present within the renal mass. RESULTS: Twenty-three (100%) of the 23 angiomyolipomas showed india ink artifact within the mass or at its interface with the kidney, and 18 (78.3%) of the 23 angiomyolipomas showed signal loss on opposed-phase MR images. In 24 (100%) of the 24 hemorrhagic-proteinaceous cysts, india ink artifact was not present within the mass or at its interface with the kidney. No signal loss was seen in hemorrhagic-proteinaceous cysts on opposed-phase MR images. In one (4%) of the 23 solid (nonangiomyolipoma) renal masses, the india ink artifact was identified at the interface of the mass with the kidney, and in two (9%) of the 23 masses, loss of signal was identified on the opposed-phase MR images. CONCLUSION: The presence of india artifact at a renal mass-kidney interface or within a renal mass is indicative of angiomyolipoma.

Aged↗
PubMed2004

Adrenal gland and adrenal mass calcification.

With the widespread use of computed tomography (CT), it is not unusual to find calcification within the adrenal glands. There are a variety of adrenal lesions that may calcify, but usually the appearance of the calcification is not specific. However, when the pattern and morphology of the adrenal calcification are combined with the other imaging features and the appropriate clinical history, the correct diagnosis may be suggested.

Adrenal Gland Diseases↗
PubMed2004

Renal masses: quantitative analysis of enhancement with signal intensity measurements versus qualitative analysis of enhancement with image subtraction for diagnosing malignancy at MR imaging.

PURPOSE: To retrospectively compare quantitative and qualitative methods of assessing magnetic resonance (MR) imaging contrast enhancement as the basis for diagnosing renal malignancy. MATERIALS AND METHODS: MR imaging was performed by using a gadolinium-enhanced breath-hold fat-suppressed three-dimensional T1-weighted gradient-echo sequence in 71 patients (48 men and 23 women; mean age, 62 years; age range, 26-87 years) with 93 renal lesions for which pathologic correlation was available. For quantitative measurements of enhancement, the relative increase in signal intensity values was measured by one investigator with manually defined regions of interest, and the threshold of an increase of 15% or greater was used to distinguish malignant from benign masses. For qualitative assessment, two investigators independently reviewed the subtracted images of all lesions and subjectively determined whether enhancement was present or absent. The sensitivity, specificity, and positive and negative predictive values for each method were calculated and compared. Mean (+/- standard deviation) and median values of relative enhancement were also calculated for benign and malignant lesions. RESULTS: At pathologic analysis, 74 (80%) of the 93 lesions were malignant, and 19 (20%)-including seven oncocytomas-were benign. For diagnosing malignancy based on enhancement alone, sensitivity and specificity, respectively, were 95% (70 of 74 lesions) and 53% (10 of 19 lesions) at quantitative analysis and 99% (73 of 74 lesions) and 58% (11 of 19 lesions) at qualitative analysis. All seven oncocytomas were considered to be malignant with both methods. When the oncocytomas were excluded, specificities increased to 83% (10 of 12 lesions) and 92% (11 of 12 lesions) for the quantitative and qualitative evaluations, respectively. Three of the four malignant lesions incorrectly characterized as benign at quantitative assessment were hyperintense on unenhanced MR images; all were diagnosed correctly at qualitative evaluation. CONCLUSION: Image subtraction enables accurate assessment of renal tumor enhancement, particularly in the setting of masses that are hyperintense on unenhanced MR images.

Adult↗
PubMed2004

Kidney transplantation: evaluation of donors and recipients.

MR imaging provides a comprehensive method for noninvasive evaluation of renal donor anatomy. Although multidetector helical CT can provide similar information, MR imaging has the advantage of avoiding exposure to ionizing radiation and potentially nephrotoxic contrast material. These are important considerations in screening a generally healthy donor population. MR imaging also can provide complete evaluation of the kidney after transplantation, where avoidance of potentially nephrotoxic agents and preservation of maximal renal function are critical.

Humans↗
PubMed2004

MR imaging of cystic renal masses.

MR imaging has proven to be an important imaging modality in the evaluation of cystic renal masses. Because it is becoming more widely used, it is necessary to be able to characterize cystic renal masses accurately using MR imaging alone. We review the indications for the use of MR imaging and discuss the findings present in a variety of cystic renal masses. The role of MR imaging in the characterization of cystic lesions of the kidney is summarized and compared with the CT findings in the Bosniak renal cyst classification. It is expected that the increasing experience with the use of MR imaging in cystic renal masses will add to our ability to diagnose and manage these cases successfully.

Humans↗
PubMed2004

Evaluation of cystic renal masses: comparison of CT and MR imaging by using the Bosniak classification system.

PURPOSE: To compare computed tomography (CT) and magnetic resonance (MR) imaging in the evaluation of cystic renal masses by using the Bosniak classification system. MATERIALS AND METHODS: Images of 69 renal masses in 59 patients (38 men, 21 women; mean age, 60.4 years; range, 30-86 years), who had undergone both CT and MR imaging examinations within 1 year (average, 60.5 days; range, 0-356 days), were retrospectively analyzed by two radiologists in consensus. For each lesion, images were compared for thickness of wall and septa, number of septa, and presence of enhancement. Each mass was categorized (Bosniak classification) first on CT images and then on MR images, and results were compared. Pathologic correlation was available in 25 lesions. RESULTS: On CT images, there were 15 category I, 16 category II, 10 category IIF, 19 category III, and nine category IV lesions. Findings on CT and MR images were similar in 56 (81%) lesions; in 13 (19%) lesions, there were differences. In eight (12%) lesions, MR imaging depicted more septa than did CT, which resulted in an upgrade of the classification at MR imaging in two cases. In seven (10%) lesions, MR imaging depicted increased wall and/or septa thickness compared with CT, resulting in a classification upgrade in six cases. Three lesions had both increased numbers of septa and thickening of the wall and/or septa. In two (3%) lesions, enhancement characteristics at CT and MR imaging were different. One of these lesions also had an increased number of septa. Overall, MR imaging results led to a cyst classification upgrade of seven lesions, from category II to IIF (n = 2), IIF to III (n = 3), or III to IV (n = 2). Pathologic correlation in 25 lesions revealed 20 malignant and five benign lesions. CONCLUSION: CT and MR imaging findings were similar in the majority of cystic renal masses. In some cases, however, MR images may depict additional septa, thickening of the wall and/or septa, or enhancement, which may lead to an upgraded Bosniak cyst classification and can affect case management.

Adult↗
PubMed2004

Comparison of unenhanced CT and chemical shift MRI in evaluating lipid-rich adrenal adenomas.

OBJECTIVE: Our aim was to evaluate adrenal adenomas in patients who underwent both unenhanced CT and chemical shift MRI to determine if adenomas can be characterized with MRI when the findings of CT are indeterminate. MATERIALS AND METHODS: Between January 1999 and June 2003, 40 patients (42 adrenal masses) underwent unenhanced CT and chemical shift MRI and were retrospectively analyzed. Hounsfield units, adrenal-to-spleen chemical shift ratio, and signal-intensity index were obtained for each adrenal mass. Qualitative analysis for loss of signal in each adrenal mass on the opposed-phase images was also performed by two reviewers and compared with the quantitative analyses. A lipid-rich adenoma was diagnosed if the mass measured equal to or less than 10 H, had an adrenal-to-spleen chemical shift ratio of less than 0.71, and had a signal-intensity index of greater than 16.5% or if the mass fulfilled two of the preceding criteria and had follow-up imaging without change. RESULTS: The sensitivities and specificities for diagnosing a lipid-rich adenoma using the qualitative, adrenal-to-spleen chemical shift ratio, signal-intensity index, and unenhanced CT attenuation analyses were 92% (33/36) and 17% (1/6), 100% (36/36) and 100% (6/6), 100% (36/36) and 67% (4/6), and 78% (28/36) and 83% (5/6), respectively. Twenty-eight (67%) lipid-rich adenomas measured equal to or less than 10 H, had an adrenal-to-spleen chemical shift ratio of less than 0.71, and had a signal-intensity index of greater than 16.5%. Eight masses (19%) measured greater than 10 H but had an adrenal-to-spleen chemical shift ratio of less than 0.71 and a signal-intensity index greater than 16.5% and were unchanged at follow-up. CONCLUSION: Eight (62%) of 13 adrenal adenomas measuring greater than 10 H on unenhanced CT were definitively characterized with chemical shift MRI.

Adenoma↗
PubMed2003

MR imaging evaluation of myocardial viability in the setting of equivocal SPECT results with (99m)Tc sestamibi.

PURPOSE: To determine if contrast material-enhanced magnetic resonance (MR) imaging is useful for assessment of myocardial viability in patients with equivocal stress-rest results from single photon emission computed tomographic (SPECT) examination with technetium 99m sestamibi. MATERIALS AND METHODS: Twenty patients underwent stress-rest SPECT examinations with sestamibi. Results were considered equivocal for assessment of myocardial infarct on the basis of fixed perfusion defects that either had normal wall motion or exceeded any wall motion abnormalities. Patients then underwent (a). contrast-enhanced MR imaging for assessment of myocardial infarct and (b). cine MR imaging for assessment of wall motion. For image analyses, the left ventricle was divided into 14 segments. Wall motion and extent of infarct were assessed independently and compared. RESULTS: Forty-one segments were equivocal for infarct at SPECT, and most (21 of 41 [51%]) involved the posterior or inferior wall. Infarct was confirmed with MR imaging in 10 of 41 (24%) equivocal segments in eight patients (40%). An additional 29 segments in eight patients had infarct at MR imaging that was not suspected at SPECT, including segments in three patients with no clinical history of myocardial infarct prior to imaging. All cases of infarct except one that were equivocal or undetected with sestamibi at SPECT were nontransmural at MR imaging, and most of the unsuspected subendocardial infarcts (15 of 28 [54%]) had no associated wall motion abnormalities. CONCLUSION: Patients with radionuclide examination findings that are equivocal for infarct may benefit from contrast-enhanced MR imaging, particularly in the setting of nontransmural infarct.

Adult↗
PubMed2003

MR imaging of the kidneys and adrenal glands.

By performing a comprehensive MR imaging examination, it is not only possible accurately to characterize and stage cystic and solid lesions of the kidney, but also to provide important preoperative information to the surgeon. In addition, MR imaging can characterize many adrenal lesions and frequently can obviate the need to obtain biopsies. The continued development and growth of MR technology combined with the current trend toward minimally invasive surgery will expand the role of MR imaging in the future.

Adrenal Gland Diseases↗
PubMed2003

Renal imaging for diagnosis and staging of renal cell carcinoma.

The development and expansion of CT and MRI technology have enhanced the detection and characterization of renal lesions. Although these advancements should lead to earlier diagnosis of renal cell carcinoma with subsequent improved cure rates, the increased imaging has also uncovered many cases that are problematic not only in diagnosis but in management as well. The performance of high-quality examinations combined with growing experience should improve the ability to diagnose and manage these cases successfully. Continued advances in CT and MR technology combined with the current trend toward minimally invasive surgery will continue to expand the role of preoperative imaging and, it is hoped, improve the cure rate of renal cancer.

Carcinoma, Renal Cell↗
PubMed2003

Calcification in cystic renal masses: is it important in diagnosis?

PURPOSE: To determine whether the presence of calcifications in cystic renal masses is important in diagnosis and to suggest an approach to the management of calcified cystic renal masses. MATERIALS AND METHODS: Eighty-one cystic renal masses containing calcification in a wall or septum were evaluated by means of review of computed tomographic (CT) images (n = 81), follow-up CT images (n = 28), and results of pathologic examination (n = 40) by the authors in consensus. Images were evaluated for lesion size, amount and morphology of calcification, and any association of calcification with soft-tissue structures. Lesions were categorized according to the Bosniak cyst classification system; the amount of calcification was determined with a subjective grading system. Progression of calcification was qualitatively determined with available follow-up CT scans. RESULTS: Twenty-one lesions were Bosniak category II (benign) and showed small amounts and thin strands of calcification. Nineteen lesions containing more extensive calcification but no enhancing tissue were category IIF. Follow-up CT results available for 16 of these lesions (average follow-up length, 5 years 8 months) showed no substantial change. The three remaining lesions were proved benign at surgery. Twenty-five lesions were category III; surgical intervention was performed in 21 of these (benign, n = 12; malignant, n = 9). Sixteen lesions that contained obvious areas of enhancing soft tissue were category IV and proved malignant at surgery. CONCLUSION: Calcification in a cystic renal mass is not as important in diagnosis as is the presence of associated enhancing soft-tissue elements. This information should enable a reasonable approach to the management of calcium-containing renal cystic lesions.

Calcinosis↗