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M Korobkin

Publications and source records attributed to M Korobkin.

At least 37 records · Page 2Linked to original sources
PubMed1997

Imaging of adrenal masses.

Most adrenal masses are detected on CT scans, but only a minority has morphologic features that are characteristic of a specific histologic diagnosis. In patients with clinical or biochemical features of a hyperfunctioning adrenal syndrome, CT detection of a unilateral adrenal mass typically leads to surgical resection, although functional assessment of the mass with iodomethylnorcholesterol or MIBG scintigraphy sometimes is used to augment the CT findings. In patients with a nonhyperfunctioning adrenal mass, chemical shift MR and CT densitometry have begun to replace percutaneous adrenal biopsy or serial follow-up CT as methods to establish a specific diagnosis. In this article the authors review the clinical features and imaging findings of patients with known or suspected adrenal masses.

Adenoma↗
PubMed1997

Intrapericardial paragangliomas (pheochromocytomas): imaging features.

OBJECTIVE: The imaging features of intrapericardial paragangliomas (pheochromocytomas) are described. MATERIALS AND METHODS: We conducted a retrospective study of the imaging features of all intrapericardial paragangliomas seen at our institution over the last 13 years. RESULTS: In this study, intrapericardial paragangliomas were typically located adjacent to or involved the left atrium. The diameter of the tumors ranged from 3 to 8 cm. Metaiodobenzylguanidine (MIBG) scintigraphy revealed 11 of 12 tumors (sensitivity = 92%). After MIBG scintigraphic location, dynamic contrast-enhanced CT revealed all 12 tumors. CONCLUSION: Intrapericardial paragangliomas are rare tumors, typically located adjacent to or involving the left atrium. For initial detection, regional location of these extraadrenal tumors, and detection of distant metastases, MIBG scintigraphy is recommended. Dynamic contrast-enhanced CT or MR imaging can then provide detailed anatomic delineation before surgical resection.

3-Iodobenzylguanidine↗
PubMed1997

CT appearance of lipomatous hypertrophy of the interatrial septum.

OBJECTIVE: We undertook this study to determine the CT findings of lipomatous hypertrophy of the interatrial septum, an asymptomatic and underrecognized benign proliferation of fat within the atrial septum. MATERIALS AND METHODS: We retrospectively identified 12 cases of lipomatous hypertrophy of the interatrial septum by searching the radiology records at our institution from 1991 to 1995. We reviewed the CT scans of these patients to determine the distribution and morphology of fat within the interatrial septum. RESULTS: In all patients with lipomatous hypertrophy, a mass of fat attenuation extended from the coronary sinus to just above the level of the aortic root with relative sparing of the fossa ovalis, which resulted in a dumbbell configuration. Average dimensions were 7 cm for craniocaudal extent (range, 6-9 cm), 4.5 cm along the interatrial septum (range, 3.6-6.2 cm), and 2.7 cm perpendicular to the septum (range, 1.5-4.8 cm). Increased epicardial fat was seen on CT scans in 10 patients (83%). CT revealed mediastinal lipomatosis in six patients (50%). No patients had undergone corticosteroid treatment or total parenteral nutrition. No electrocardiographic or functional cardiac abnormalities were seen. CONCLUSION: On standard, high-resolution, and enhanced CT images, lipomatous hypertrophy of the interatrial septum is shown as a nonenhancing smoothly marginated homogeneous dumbbell-shaped mass of fat attenuation confined to the interatrial septum. These characteristic morphologic features allow confident diagnosis and help differentiate this benign condition from other cardiac masses.

Adipose Tissue↗
PubMed1997

Helical CT evaluation of potential kidney donors: findings in 154 subjects.

OBJECTIVE: The purpose of our study was to assess renal helical CT (RHCT) as the primary imaging technique in the evaluation of potential kidney donors. SUBJECTS AND METHODS: Unenhanced and enhanced (3-mm collimation) RHCT was performed in 154 kidney donors using 125-150 ml of i.v. contrast material at an injection rate of 3 or 4 ml/sec and a pitch of 1.3-2. Scans were reconstructed at 1.5-mm intervals for a three-dimensional image. RHCT images were compared with the results of renal arteriography (RA) (50 subjects) and surgery (117 subjects). RESULTS: CT and surgical findings agreed in 95% of patients (111/117), with five cases of missed accessory arteries (all < 2 mm in diameter) and one case of a missed early division of the main artery. In the 50 subjects who underwent CT and RA, imaging revealed concordance in 96% of 100 kidneys. One small accessory artery was not detected by CT (origin from the common iliac artery). RA did not detect accessory arteries in three subjects. All 22 kidneys with early dividing main arteries (< 1.5 cm from the aortic origin) were identified by both RHCT and RA. Axial and three-dimensional CT images were complementary: five small accessory arteries were seen well only on the axial sections, whereas four early dividing arteries and two cases of renal artery stenosis were prospectively identified only on the three-dimensional images. Twenty-five renal vein anomalies were detected only by CT. In the full series of 154 subjects, nonvascular renal findings included renal calculi (n = 11), cysts (n = 12), duplicated ureters (n = 6), horseshoe kidney (n = 1), and pelvic kidney (n = 1). CONCLUSION: RHCT can be the primary imaging technique in the assessment of potential kidney donors, reducing the number of examinations as well as the risk and cost of imaging in these subjects.

Adult↗
PubMed1997

Incidentally discovered adrenal masses.

Incidentally discovered adrenal masses are a common clinical problem. Most of these masses lack specific imaging features that enable accurate characterization. In this article, the authors describe the imaging findings, as well as the roles of various imaging techniques that are currently used to evaluate these masses.

Adrenal Gland Neoplasms↗
PubMed1996

Cystic renal masses: a reevaluation of the usefulness of the Bosniak classification system.

RATIONALE AND OBJECTIVES: We evaluated the utility of the Bosniak system for classifying cystic renal masses on computed tomography (CT) scans. METHODS: The CT scans of 20 patients with 24 cystic renal masses that were subsequently surgically removed or biopsied were reviewed retrospectively. Masses were categorized using the Bosniak system and were correlated with the pathology results. RESULTS: The final pathology results of the cystic renal masses were as follows: Seven of seven category I lesions were benign, one of five category II lesions was benign, zero of four category III lesions were benign, and zero of six category IV lesions were benign. Neither of two unclassifiable cystic lesions were benign. The average enhancement of lesions in categories II, III, and IV was 6.3, 2.3, and 27.6 Hounsfield units (H), respectively. The two uncategorizable lesions had a mean enhancement of 26.8 H. CONCLUSION: The results of our study serve to underscore some limitations of the Bosniak classification system because most of our category II and all of our category III lesions were malignant, suggesting that minimally complex cystic renal masses may contain malignant cells. Contrast enhancement of less than 10 H was demonstrated in lesions in categories II and III.

Adenocarcinoma↗
PubMed1996

Potential renal donors: comparison of conventional imaging with helical CT.

PURPOSE: To assess helical computed tomography (CT) as a potential substitute for intravenous urography and renal angiography in the evaluation of living potential renal donors. MATERIALS AND METHODS: Helical CT was performed in 32 potential donors both before and after administration of contrast material. Scans were reconstructed at 1.5-mm intervals for three-dimensional reconstructions. Helical CT images were blindly compared with urograms (n = 32) and renal angiograms (n = 24). RESULTS: One small accessory artery was not depicted with helical CT, and angiography did not depict an accessory artery arising in proximity to the origin of the main renal artery. All eight kidneys with early dividing main arteries were identified with both helical CT and angiography. Three renal venous anomalies were depicted only with helical CT. Helical CT and urography equally depicted nonvascular findings. CONCLUSION: Renal helical CT is a suitable replacement for intravenous urography and angiography in the assessment of living renal donors.

Adult↗
PubMed1996

Delayed enhanced CT for differentiation of benign from malignant adrenal masses.

PURPOSE: To determine whether adenomas can be differentiated from nonadenomas on 1-hour-delayed enhanced computed tomographic (CT) scans. MATERIALS AND METHODS: In a prospective evaluation of 51 adrenal masses in 39 patients, the CT attenuation was measured at the time of contrast enhancement and 1 hour later. The results were compared for adenomas (n = 41) and metastases (n = 10). RESULTS: On 1-hour-delayed enhanced CT scans, the mean attenuation of the adenomas was 11 HU +/- 13 versus 49 HU +/- 8.3 for metastases (P < .001). At a threshold value of 30 HU, specificity and positive predictive value for the diagnosis of adenoma were 100% with a sensitivity of 95%. The mean decrease in attenuation during the 1-hour delay was 74% +/- 37 for the adenomas versus 31% +/- 28 for the metastases (P < .001). CONCLUSION: CT densitometry on delayed scans obtained 1 hour after contrast enhancement may be useful in characterizing an adrenal mass as an adenoma. When CT is performed with a 150-mL bolus injection of contrast material and with the scanning parameters described in this study, other procedures or imaging studies may be unnecessary if the mass measures less than 30 HU on the delayed scans.

Adenocarcinoma↗
PubMed1996

Adrenal adenomas: relationship between histologic lipid and CT and MR findings.

PURPOSE: To assess the relationship between the quantity of lipid in resected adrenal adenomas and the unenhanced computed tomographic (CT) attenuation number and the relative change in signal intensity on chemical shift magnetic resonance (MR) images. MATERIALS AND METHODS: The percentage of lipid-rich cortical cells in histologic sections from 20 resected adrenal adenomas was assessed. The results were correlated with the corresponding unenhanced CT attenuation number or the relative change in signal intensity on chemical shift MR images, or both. RESULTS: There was an inverse linear relationship between the percentage of lipid-rich cortical cells in the adrenal adenomas and the unenhanced CT attenuation number (R2 = .68, P = .0005). There was a similar inverse linear relationship to the relative change in MR signal intensity on chemical shift images by using both quantitative (R2 = .83, P = .004) and qualitative (R2 = .70, P = .019) assessment. CONCLUSION: The presence and amount of histologic lipid in many adrenal adenomas accounts for their low attenuation on unenhanced CT scans and their loss in relative signal intensity on chemical shift MR images.

Adenoma↗
PubMed1996

Differentiation of adrenal adenomas from nonadenomas using CT attenuation values.

OBJECTIVE: The purpose of our study was to determine whether unenhanced CT attenuation value, enhanced CT attenuation value, or lesion size can be used to differentiate adrenal adenomas from nonadenomatous adrenal masses. MATERIALS AND METHODS: We retrospectively assessed the CT scans of 135 adrenal masses in 124 patients with a variety of adrenal masses. There were 93 cortical adenomas (85 nonhyperfunctioning adenomas, four Cushing's adenomas, and four primary aldosteronism adenomas). The nonadenomas consisted of 34 metastases, four cortical carcinomas, and four pheochromocytomas. The scattergrams and mean values of the size and attenuation values on enhanced and unenhanced scans were correlated with the final diagnoses. Results were also subjected to receiver operating characteristic analysis. RESULTS: Forty-one adenomas and 20 nonadenomas had unenhanced CT. The mean attenuation value of the 41 adenomas was significantly lower (p < .001) than that of the nonadenomas (2.5 H +/- 14 compared with 32 H +/- 6.4). The lowest unenhanced CT attenuation value of the nonadenomas was 18 H; therefore, the sensitivity:specificity ratio for the diagnosis of adenomas was 85%:100% at a threshold value of 18 H. At this threshold, the positive predictive value was 100% and the negative predictive value was 77%. For the 85 masses with enhanced CT, the mean attenuation of the 60 adenomas was also significantly lower (p < .01) than for the 25 nonadenomas (47 H +/- 24 compared with 62 H +/- 21). The lowest enhanced CT attenuation value of the nonadenomas was also 18 H, but the sensitivity:specificity ratio was only 10%:100% at this threshold value of 18 H. Although the mean diameter of the adenomas was significantly lower (p < .001) than for the nonadenomas (2.4 cm +/- 0.9 compared with 4.5 cm +/- 2.5), there was sufficient overlap between the two groups at the smallest sizes that a threshold value for a highly specific diagnosis of adenoma was not present. The area under the receiver operating characteristic curve for unenhanced CT attenuation values (0.98 +/- 0.02) was significantly greater than the area for enhanced CT values (0.68 +/- 0.06, p < .001) and the area for size (0.79 +/- 0.04, p < .001). CONCLUSIONS: Unenhanced CT attenuation values can characterize an adrenal mass as a benign adenoma with high specificity and acceptable sensitivity. Adrenal masses cannot be characterized using enhanced CT attenuation values or lesion size.

Adenoma↗
PubMed1996

The incidental adrenal mass.

This article discusses the accuracy and complications of percutaneous biopsy of adrenal masses and the rapidly evolving new methods for noninvasive differential diagnosis using CT scan, MR imaging, and radio-nuclide scintigraphy. We offer our current recommendations for the evaluation of benign versus malignant adrenal masses and speculate on the optimal approach for the near future.

Adrenal Gland Diseases↗
PubMed1996

Pheochromocytoma.

Pheochromocytomas are rare tumors that can pose problems in diagnosis and detection. Although they usually present with classic symptoms, they can at times present with symptoms that mimic other clinical conditions. This article discusses the various imaging tests that are used in pheochromocytoma detection and also outlines an imaging algorithm used at the University of Michigan for pheochromocytoma evaluation.

Adrenal Gland Neoplasms↗
PubMed1995

Scintigraphy of incidentally discovered bilateral adrenal masses.

The purpose of this study was to determine the patterns of iodine-131 6 beta-iodomethylnorcholesterol (NP-59) imaging and the correlation with computed tomography (CT)-guided adrenal biopsy and follow-up in patients with bilateral adrenal masses. To this end we investigated a consecutive sample of 29 euadrenal patients with bilateral adrenal masses discovered on CT for reasons other than suspected adrenal disease. Adrenal scintigraphy was performed using 1 mCi of NP-59 injected intravenously, with gamma camera imaging 5-7 days later. In 13 of the 29 patients bilateral adrenal masses were the result of metastatic involvement from lung carcinoma (5), lymphoma (3), adrenocarcinoma of the colon (3), squamous cell carcinoma of the larynx (1), and anaplastic carcinoma of unknown primary (1). Among these cases the NP-59 scan demonstrated either bilaterally absent tracer accumulation (in eight, all with bilateral metastases proven by CT-guided biopsy or progression on follow-up CT) or marked asymmetry of adrenocortical NP-59 uptake (in five). Biopsy of the adrenal demonstrating the least NP-59 uptake documented malignant involvement of that gland in five of five patients. In two patients an adenoma was found simultaneously in one adrenal with a contralateral malignant adrenal mass. In each of these cases, the adenoma demonstrated the greatest NP-59 uptake. In 16 patients diagnosis of adenoma was made on the basis of (a) CT-guided adrenal biopsy of the gland with the greatest NP-59 uptake of the pair (n = 4), or (b) adrenalectomy (n = 2), or (c) absence of change in the size of the adrenal mass on follow-up CT scanning performed 6 months to 3 years later (n = 10).(ABSTRACT TRUNCATED AT 250 WORDS)

Adosterol↗
PubMed1995

Adrenal imaging.

CT is the imaging procedure of choice for detecting adrenal masses. In patients with biochemical evidence of an adrenal endocrine syndrome, CT can detect or exclude an adrenal mass in a high percentage of cases. Radionuclide scintigraphy is a useful adjunct in selected cases to characterize an adrenal mass as functional cortical (NP-59) or medullary (MIBG) tissue. In this article, the spectrum of adrenal imaging findings in patients with Cushing's syndrome, Conn's syndrome (primary aldosteronism), and pheochromocytoma is described and illustrated. In patients without an adrenal endocrine syndrome, an adrenal mass is detected on CT as an incidental finding or during a search for metastatic disease. Although pathognomonic findings of adrenal hemorrhage or myelolipoma are occasionally demonstrated, most adrenal masses have nonspecific morphological CT features. Differentiation of common benign adenomas from nonadenomatous adrenal masses, including metastases, remains an important clinical problem. This article reviews the current status, advantages, and limitations of the following methods to characterize an adrenal mass: (1) percutaneous adrenal biopsy, (2) NP-59 scintigraphy, (3) unenhanced CT densitometry, and (4) opposed-phase chemical shift MRI.

Adenoma↗
PubMed1995

Small echogenic renal masses: how often is computed tomography used to confirm the sonographic suspicion of angiomyolipoma?

OBJECTIVES: Although renal angiomyolipoma (AML) has a typical ultrasound appearance, many authorities suggest that a computed tomography (CT) scan be obtained to confirm the diagnosis because small echogenic renal cell carcinomas can simulate AML. Our study evaluates the actual follow-up in such patients and factors that may affect whether CT confirmation is recommended or obtained. METHODS: From 1986 through 1992, 36 patients had an ultrasound diagnosis of probable renal AML (well-circumscribed, homogenously echogenic mass). In each case the patient's age, symptoms, ultrasound results and recommendations, and imaging follow-up were recorded. RESULTS: CT confirmation of the sonographic diagnosis was recommended in only 11 of 36 (31%) patients. Only 7 of these 11 patients actually underwent CT, 5 of whom had the diagnosis confirmed by CT detection of intratumoral fat. Ten of 23 patients (43%) over 50 years of age had CT recommended, whereas only 1 of 13 (8%) patients under age 50 years did (P < 0.05). CT confirmation was recommended for 5 of 13 (38%) lesions greater than 10 mm and for 6 of 23 (26%) smaller masses. None of the 9 patients under age 50 years with small masses (less than 10 mm) had CT recommended. CONCLUSIONS: Although many authorities recommend CT to confirm the sonographic diagnosis of renal AML, this algorithm is rarely followed in everyday clinical practice, especially in patients under age 50 years with masses less than 10 mm.

Adult↗
PubMed1995

Abdominal aortic aneurysms: CT evaluation of renal artery involvement.

PURPOSE: To determine whether computed tomography (CT) assessment of the proximal extent of ruptured aneurysms can help the surgeon determine whether to initially clamp the pararenal aneurysm neck or the supraceliac aorta. MATERIALS AND METHODS: CT scans and medical records were reviewed and compared for 30 patients with ruptured abdominal aortic aneurysms (AAAs) who underwent immediate surgical repair. RESULTS: For 49 of 50 vessels in 25 patients, the authors correctly predicted at CT that AAAs originated caudal to the main renal artery origins. They also predicted that nine main renal arteries in five patients originated directly from the AAAs, but this was correct in only five arteries. Suprarenal clamping was required in all five patients. Infrarenal clamps were used before reconstruction in all 12 of the patients whose AAAs appeared to originate at least 30 mm below the main renal arteries. CONCLUSION: CT can help predict whether an initial aortic clamp can be placed caudal to the main renal artery orifices. Its use can be predicted with 100% certainty only when an aneurysm appears to originate at least 3 cm caudal to the origin of the main renal artery.

Aged↗
PubMed1995

Renal masses: assessment of corticomedullary-phase and nephrographic-phase CT scans.

PURPOSE: To evaluate the role of thin-section helical computed tomography (CT) performed during the corticomedullary phase (CMP) and nephrographic phase (NP) of contrast enhancement in the detection and characterization of renal masses. MATERIALS AND METHODS: Renal CT scans and medical records of 33 patients were retrospectively reviewed. In all examinations, 5-mm-thick, contiguous, helical-mode scans were obtained before and 40 seconds after initiation of dynamic bolus injection of contrast material (CMP images); 5-mm-thick, contiguous, axial-mode scans were obtained after completion of CMP scanning (NP images). RESULTS: At review of CMP, NP, and combination images, 259, 389, and 417 lesions, respectively, were identified. The greatest difference in detection occurred in the renal medulla, with 25 lesions identified on CMP images and 111 lesions identified on NP images. False-positive results occurred when CMP images were reviewed without NP images. CONCLUSION: CT scans obtained only during the CMP of contrast enhancement fail to depict many renal masses that are easily seen on NP images.

False Positive Reactions↗