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M Korobkin

Publications and source records attributed to M Korobkin.

At least 55 records · Page 3Linked to original sources
PubMed1995

Characterization of adrenal masses with chemical shift and gadolinium-enhanced MR imaging.

PURPOSE: To assess the potential role of chemical shift and dynamic gadolinium-enhanced magnetic resonance (MR) imaging in the characterization of adrenal masses. MATERIALS AND METHODS: Fifty-one adrenal masses (35 adenomas and 16 nonadenomas) in 43 patients were evaluated with chemical shift MR imaging, dynamic gadolinium-enhanced MR imaging, or both. The relative change in the signal intensity (SI) ratio of the adrenal mass to liver and paraspinal muscles was quantitatively and qualitatively assessed. Opposed-phase gradient-echo (GRE) images were compared with in-phase images. RESULTS: With qualitative visual inspection, only adenomas showed a decrease in relative SI ratio on opposed-phase chemical shift images (specificity, 100%; sensitivity, 81%). Quantitative ratios corresponding to 100% specificity were also observed, with similar sensitivities. Adenomas could not be differentiated from nonadenomas with visual assessment of maximum SI after contrast material administration or washout. CONCLUSION: Characterization of an adrenal mass as an adenoma can be made with high specificity and acceptable sensitivity by visually comparing opposed-phase with in-phase GRE images.

Adenoma↗
PubMed1995

Incidentally discovered adrenal masses.

Independently, endocrinology, radiology, and nuclear medicine can not optimally differentiate the etiology of the incidental adrenal mass. Rather, the insight necessary for this task must be contributed by all three disciplines. Incidentally discovered adrenal masses are being detected at an increasing rate. This trend is expected to continue based on the incidence of adrenal masses in autopsy series and the increasing use of high resolution abdominal imaging techniques. CT and MRI are able to definitely characterize only a minority of these lesions (simple cyst, myelolipoma, obvious local malignant invasion). Biochemical screening for hormone excess is essential regardless of a nonsuggestive complete history and physical examination. An argument may be made for not further pursuing nonhypersecreting lesions with the typical features of a benign adenoma on CT scan and an attenuation value of 0 HU or less. Adrenocortical scintigraphy is recommended in all patients with normal biochemical screening tests, especially those with CT attenuation values greater than 0 HU. In this setting, we believe that the functional and anatomical information provided by NP-59 and [75Se]selenomethylnorcholesterol scintigraphy allows one to noninvasively, accurately, and less expensively (Table 9) categorize adrenal masses as benign nonhypersecretory adenomas (the vast majority) vs. a possibly malignant lesion (the minority). In the presence of normal biochemistry, a concordant NP-59 imaging pattern is diagnostic of a nonhypersecretory benign adrenal adenoma and requires no immediate therapeutic intervention. Conversely, patients with discordant patterns of NP-59 scintigraphy have lesions that carry a significant risk for malignancy, and the pursuit of a tissue diagnosis is indicated, usually by means of FNA. Normal adrenocortical tissue on cytological studies in this setting may represent inadvertent sampling of adjacent normal adrenocortical tissues or the presence of a well differentiated adrenocortical carcinoma. In patients with lesions larger than 2 cm in whom NP-59 scintigraphy is nonlateralizing, the possibility of a periadrenal or pseudoadrenal mass is likely and should prompt review, or perhaps even repeat, of high resolution adrenal imaging (occasionally angiography may be helpful). In lesions shown to be 2 cm or less in size with a nonlateralizing NP-59-scan, there is a possibility of a periadrenal or pseudoadrenal mass; however, once this is excluded it must be recognized that benign and malignant lesions, because of the limitations of scintigraphy, cannot always be clearly distinguished by this method when masses are small.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenal Gland Diseases↗
PubMed1994

Retroperitoneal plexiform neurofibromas: CT findings.

OBJECTIVE: CT findings in retroperitoneal plexiform neurofibromas have been described previously only in a few case reports. This study was performed to characterize the CT features in a larger group of patients with this benign neoplasm and to delineate those findings that suggest the presence of concurrent malignant tumors of the nerve sheath. MATERIALS AND METHODS: From a review of CT scans showing retroperitoneal masses in 25 patients with neurofibromatosis type 1, we identified 16 patients whose clinical and CT features suggested the diagnosis of plexiform neurofibromas. The diagnosis was confirmed by biopsy of the mass in three patients. In the remaining 13 patients, the diagnosis was supported by long-term follow-up in eight and by biopsy confirmation of either a neurofibroma or a plexiform neurofibroma elsewhere in the body in the other five patients. Concurrent retroperitoneal malignant tumors of the nerve sheath were confirmed by biopsy in five patients. RESULTS: CT showed bilateral, remarkably symmetric masses extending along the medial and posterior aspects of the psoas muscles in 15 of the 16 patients. Parapsoas masses tended to be long and cylindrical. In addition to parapsoas masses, eight patients had bilateral, symmetric masses extending along the anterior aspect of the sacrum in a sheetlike fashion. Masses were identified in the region of the celiac axis and the origin of the superior mesenteric artery in four patients. Only one patient had an isolated celiac/superior mesenteric artery mass without associated parapsoas or presacral masses. Retroperitoneal masses were of homogeneous, low attenuation when compared with adjacent muscle on CT images of 14 patients. Two patients had an unusual swirling and serpiginous pattern of increased attenuation superimposed on a low-attenuation background. Asymmetry in size and attenuation was due to malignant nerve sheath tumors in five patients. CONCLUSION: Retroperitoneal plexiform neurofibromas have a characteristic appearance on CT scans. They are typically bilateral, symmetric, low-attenuation masses in a parapsoas or presacral location. Asymmetry in size and attenuation of a larger mass suggests the possibility of a malignant tumor of the nerve sheath. Recognition of the CT features of a retroperitoneal plexiform neurofibroma can obviate the expense, pain, and risk of an unnecessary biopsy. Conversely, detection of findings suggestive of malignant tumor can lead to appropriate recommendation of biopsy.

Adult↗
PubMed1994

CT-detected renal arterial calcification: correlation with renal artery stenosis on angiography.

OBJECTIVE: The purpose of this study was to determine whether a relationship exists between CT-detected calcifications in the main renal artery and renal artery stenosis. We also evaluated whether renal artery calcifications are more indicative of stenosis in particular patient subgroups based on age, sex, or hypertensive status. MATERIALS AND METHODS: We retrospectively reviewed the examinations of 70 patients (122 kidneys) undergoing both abdominal CT and angiography for various clinical conditions, most commonly evaluation of a tumor or aneurysm. CT studies were evaluated for degree of calcification at the orifice and in the proximal and distal segments of the main renal artery. The angiograms were evaluated for degree of narrowing. Renal artery stenosis was defined as a reduction in cross-sectional area of 75% or more. A separate analysis was performed on male and female patients above and below 65 years of age, with and without hypertension. RESULTS: Renal arteries with clumps of calcium (> 3 mm in diameter) had a higher percentage of stenosis (7/16, 44%) than did renal arteries with less calcium (16/53, 30%), and renal arteries with no calcium had the fewest stenoses (9/53, 17%; p = .02). Calcifications in the renal artery were not good predictors of stenosis as they were frequently seen in arteries with nonsignificant narrowing and were occasionally seen in arteries with no narrowing. The patient's sex was not a significant factor in this analysis (p = .34). Renal artery calcifications in hypertensive patients showed a stronger association with renal artery stenosis, but the overall ability to predict stenosis remained poor. However, calcification may be significant in persons less than 65 years old, in whom this finding was associated with stenosis all three cases (100%). Similar calcifications in patients 65 years old or more were associated with stenosis in only 4 (31%) of 13 cases (p < .01). CONCLUSION: CT-detected calcifications in renal arteries are associated with stenosis, but their predictive value in the general population or in hypertensive patients is poor. These calcifications in a patient less than 65 years of age are a better indicator of stenosis of the renal artery.

Calcinosis↗
PubMed1994

Abdominal aortic aneurysm morphology: CT features in patients with ruptured and nonruptured aneurysms.

OBJECTIVE: We evaluated a variety of internal architectural features in ruptured and nonruptured abdominal aortic aneurysms to determine whether any features are associated more frequently with ruptured abdominal aortic aneurysms. These features may be useful in identifying subtle ruptures when no obvious retroperitoneal hematoma is present and may be helpful in predicting unstable aneurysms at risk for rupture. MATERIALS AND METHODS: The CT scans of 52 patients with ruptured abdominal aortic aneurysms were reviewed and compared with those of 56 patients with asymptomatic nonruptured aneurysms exceeding 4.5 cm in diameter. All aneurysms were evaluated for size, rim calcification, thrombus amount, thrombus calcification, and lumen irregularity. In addition, four different thrombus patterns were identified and evaluated, including homogeneous, diffusely heterogeneous, periluminal halo, and crescent patterns. Statistical comparisons were adjusted for differences in size between the two groups. RESULTS: Age, gender, and aneurysm length were not statistically different between the two groups. A larger diameter was found in the ruptured aneurysm group: 7.4 (anteroposterior) x 7.9 (transverse) cm versus 5.9 x 6.1 cm (p = .00001). More thrombus surrounded the nonruptured aneurysms (p = .014). Thrombus calcification was seen in 25% (14/56) of the control group and in 13% (7/52) of the rupture group (p = .01). Two thrombus patterns, homogeneous and periluminal halo, were encountered with similar frequencies in both groups. The diffusely heterogeneous pattern was seen more in the control group. A crescent of increased attenuation was encountered only in patients with ruptured aneurysms, at an incidence of 21% (11/52) (p = .0005). Thick and thin wall calcifications were seen in both groups, but a focal discontinuity in circumferential calcification was seen only in association with ruptured aneurysms, at an incidence of 8% (4/52) (p = .008). There was no significant difference in the number of patients whose patent lumen was irregular. CONCLUSION: In our series, detection of a high-attenuation crescent or focal gap of otherwise circumferential wall calcification is associated with aneurysm rupture. The homogeneous, diffusely heterogeneous, and periluminal halo patterns are not specifically associated with aortic rupture. There were no significant differences in the amount of wall calcification or frequency of lumenal irregularity between patients with ruptured and those with nonruptured aneurysms.

Aged↗
PubMed1993

Role of femoral vessel catheterization and altered hemostasis in the development of extraperitoneal hematomas: CT study in 44 patients.

OBJECTIVE: To ascertain the role of femoral vessel catheterization and altered hemostasis in the development of extraperitoneal hematomas, we evaluated CT scans to study the locations of extraperitoneal hematomas in three distinct clinical settings: (1) after femoral vessel catheterization with concurrent altered hemostasis due to anticoagulant, thrombolytic, and/or antiplatelet therapy (catheterized-altered hemostasis group); (2) after femoral vessel catheterization without altered hemostasis (catheterized group); and (3) with no history of femoral vessel catheterization, with or without altered hemostasis caused by a bleeding diathesis or pharmacotherapy (uncatheterized group). MATERIALS AND METHODS: Forty-four patients were identified who had CT evidence of extraperitoneal hematomas. Twenty-four were in the catheterized-altered hemostasis group, one was in the catheterized group, and 19 were in the uncatheterized group. CT scans were evaluated for anatomic subspace involvement by hemorrhage and for the presence or absence of contiguity between the hematoma and the femoral vessels. RESULTS: Bilateral hematomas were present in six of 24 patients in the catheterized-altered hemostasis group and in four of 19 patients in the uncatheterized group. We found no significant difference between the catheterized-altered hemostasis and the uncatheterized groups regarding the proportion of cases involved at any individual retroperitoneal site (p > .05). The mean number of hematoma sites in the catheterized-altered hemostasis group (4.3) was not significantly different from the mean number in the uncatheterized group (3.7) (p > .05). Contiguity between the sites of hematoma and the punctured femoral vessels was present in 75% of the patients in the catheterized-altered hemostasis group; contiguity between the hematoma and a groin was seen in 58% in the uncatheterized group. Twenty-two of 24 patients in the catheterized-altered hemostasis group had CT findings of subcutaneous fat infiltration in the groin; however, six of 19 patients in the uncatheterized group also had this finding, indicating that its presence does not always represent changes caused by catheterization. CONCLUSION: Retroperitoneal hematomas in patients with altered hemostasis and femoral vessel catheterization do not show a unique distribution attributable solely to contiguous spread of blood from the vessel puncture site. Many of these hematomas probably arise at sites distant from the femoral vessel puncture. When the hematoma is not contiguous with the punctured femoral vessels, altered hemostasis is most likely the cause of the hemorrhage.

Catheterization, Peripheral↗
PubMed1993

Duodenal injuries caused by blunt abdominal trauma: value of CT in differentiating perforation from hematoma.

OBJECTIVE: Traumatic duodenal perforation requires emergent surgery, whereas duodenal hematoma can often be treated nonsurgically. We assessed the CT findings in patients with blunt duodenal trauma to determine if CT can be used to differentiate these two duodenal injuries. MATERIAL AND METHODS: Seven consecutive patients with blunt duodenal trauma (three with perforation, four with hematoma) who underwent CT as part of their initial diagnostic evaluation were included in the study. All three perforations and one of four hematomas were surgically proved. Diagnoses of duodenal hematoma in the other three patients were based on typical features on upper gastrointestinal studies and complete resolution of clinical findings after conservative treatment. The CT scans were retrospectively reviewed without knowledge of the specific type of duodenal injury, and the findings were correlated with the results of the gastrointestinal studies and surgical findings. RESULTS: CT showed extraluminal gas or extravasated oral contrast material or both in the right anterior pararenal space in all three patients with duodenal perforation and in none of the patients with duodenal hematoma. Thickening of the duodenal wall and fluid in the right anterior pararenal space were seen in both groups of patients. CONCLUSION: Although the number of patients in the study was small, the results suggest that CT may be useful in differentiating duodenal perforation from hematoma without perforation. Extraluminal gas or extravasated oral contrast material or both were seen in the right anterior pararenal space in all three patients who had perforation and in none of the patients who had hematoma alone.

Abdominal Injuries↗
PubMed1992

CT of the extraperitoneal space: normal anatomy and fluid collections.

Knowledge of the appearance and location of the normal fascial structures surrounding the kidneys and the bladder is the key to proper CT analysis of extraperitoneal fluid collections. Recent studies have shown that the renal fascia and the perirenal space are more complex than previously recognized. An extracapsular renal hematoma, confined against the kidney by the posterior renorenal septum within the perirenal space, can entirely simulate a subcapsular hematoma. Pancreatitis fluid can dissect between the discrete layers that constitute the posterior renal fascia, allowing fluid in the anterior pararenal space to extend posterior to the kidney without directly involving the posterior pararenal space. The umbilicovesical fascia separates the small perivesical space from the potential large reservoir of the prevesical space in the extraperitoneal portion of the pelvis. Fluid in the prevesical space can communicate directly with the retroperitoneal spaces surrounding the kidney. In addition to compartmental localization, CT features of the fluid itself or the presence of ancillary findings such as aortic aneurysm, enlarged pancreas, renal mass, or hydronephrosis will frequently indicate the cause and the extent of most extraperitoneal fluid collections.

Contrast Media↗
PubMed1992

Focal and diffuse benign hepatic disease: correlative imaging.

With the large numbers of screening CT scans and ultrasounds performed in a busy radiologic practice, it is not uncommon to discover an unexpected focal or diffuse process in the liver. When there is no history of primary malignancy, many of these lesions are benign. We discuss the variety of benign focal and diffuse diseases that can be readily imaged within the liver using ultrasound, CT, and MR.

Cysts↗
PubMed1991

Percutaneous biopsy of left adrenal masses: prevalence of pancreatitis after anterior approach.

Acute pancreatitis is an unusual but recognized complication of percutaneous aspiration biopsy of the pancreas. As the pancreatic tail is located anterior to the left adrenal gland, percutaneous biopsy of a left adrenal mass via the anterior approach may result in needle passage through the tail of the pancreas with subsequent potential development of pancreatitis. To evaluate this risk, we retrospectively reviewed 48 CT-directed percutaneous aspiration biopsies of left adrenal masses done between 1984 and 1989 at two institutions. Positioning of the patient, the course of the needle, the number of needle passes, and the size of the needle were analyzed. Thirty-three (69%) of 48 biopsies of a left adrenal mass were performed by using the anterior approach. The pancreas was traversed by one or more needles in 32 of 33 cases. Biopsies were performed with 20- to 22-gauge needles, and the number of needle passes varied widely. The medical records of the 33 patients in whom the anterior approach was used also were reviewed for complications. Acute pancreatitis, which required 11-13 days of hospitalization, developed in two patients (6%). None of the other 31 patients suffered a complication. We conclude that the pancreatic tail is routinely traversed by the biopsy needle when biopsy of a left adrenal mass is done via the anterior approach and that severe acute pancreatitis can occur as a result.

Acute Disease↗
PubMed1991

Traumatic pneumoperitoneum. Implications of computed tomography diagnosis.

Pneumoperitoneum detected on plain radiographs following blunt abdominal trauma is nearly pathognomonic of bowel perforation and usually mandates exploratory laparotomy. To determine the significance of computed tomography (CT)-detected pneumoperitoneum, we reviewed the clinical records and imaging studies of all trauma patients in our hospital over a seven-year period whose abdominal CT scans showed free intraperitoneal gas. Patients who had penetrating injuries or peritoneal lavage prior to CT were excluded. Of the 18 patients who met these inclusion criteria, surgically confirmed bowel injury was found in only four (22%). In the remaining 14 patients, no evidence of gastrointestinal perforation was found by exploratory laparotomy (2 patients), diagnostic peritoneal lavage (4 patients), GI studies and clinical follow-up (6 patients), or clinical follow-up alone (5 patients). Seven patients had a pneumothorax as a possible cause for pneumoperitoneum. Two additional patients were on mechanical ventilation. Unlike pneumoperitoneum seen on plain film, CT-detected pneumoperitoneum is not pathognomonic of bowel perforation. While laparotomy is not mandatory in the non-surgically explored patient, close clinical observation is essential, and additional diagnostic tests such as peritoneal lavage or radiographic contrast studies can be beneficial to confirm the absence of intestinal injury.

Abdominal Injuries↗
PubMed1990

Leiomyoma of the kidney: presentation of 4 new cases and the role of computerized tomography.

Renal leiomyoma is a challenging diagnostic and therapeutic condition. It is clinically similar in presentation and radiographic appearance to its malignant counterpart, leiomyosarcoma. We review 30 cases of clinically diagnosed leiomyoma of the kidney from the literature, including 4 new cases with emphasis on the computerized tomography findings. Computerized tomography may locate a renal leiomyoma serendipitously in an asymptomatic patient. If the lesion is peripheral or in the parapelvic area and a plane can be seen between the tumor and kidney a capsular tumor, such as a leiomyoma of the kidney, might be considered in addition to the more common renal cell carcinoma. Renal leiomyomas have a variable radiographic pattern from that of a pure cystic to a mixed solid/cystic to an entirely solid lesion. Renal leiomyomas usually are sharply demarcated from the surroundings. Although computerized tomography cannot distinguish a renal leiomyoma from other benign or malignant renal processes the presence of invasion can virtually eliminate this benign tumor as a diagnosis. Since a preoperative diagnosis cannot be made, management involves renal exploration and radical nephrectomy in the larger lesions with a renal-sparing operation possible in selected cases. After treatment patients have a uniformly excellent prognosis.

Aged↗
PubMed1989

Overview of adrenal imaging/adrenal CT.

CT is the imaging procedure of choice for the detection of most suspected adrenal masses. But except for some patients with acute adrenal hemorrhage or fat-containing myelolipoma, the precise histologic nature of an adrenal mass is not apparent from the CT image. MIBG radionuclide scanning is useful in some patients with pheochromocytoma, whereas bilateral adrenal venous sampling for hormone assay is necessary for correct lateralization in some patients with a small aldosterone-producing adenoma. The potential value of MR imaging in the characterization of adrenal masses, especially to distinguish benign adrenal cortical adenomas from metastatic disease, is now under investigation. Currently percutaneous aspiration biopsy is still necessary to make this distinction in patients with an adrenal mass and a known extra-adrenal primary neoplasm.

Adrenal Gland Diseases↗
PubMed1989

Biliary cystadenoma and cystadenocarcinoma: CT and sonographic findings.

Biliary cystadenomas and cystadenocarcinomas are rare cystic neoplasms, usually intrahepatic in location, that are characterized pathologically by a multilocular appearance. We report the CT and sonographic findings in eight cases of biliary cystadenoma and three cases of biliary cystadenocarcinoma and correlate them with the surgical and pathologic findings. CT showed internal septa in eight of the 10 multiloculated lesions, whereas sonography showed septa in all five cases in which it was used. CT in two of the three cystadenocarcinomas showed thick and coarse mural and septal calcifications as well as large solid soft-tissue masses in one. CT showed mural soft-tissue nodules in the single case of a unilocular cystadenocarcinoma. Sonography and CT usually show the multilocular nature of biliary cystadenomas and cystadenocarcinomas. The presence of mural or septal nodules, discrete soft-tissue masses, and possibly thick and coarse calcifications increase the likelihood of a cystadenocarcinoma.

Adult↗
PubMed1986

CT differentiation of pleural effusion from ascites. An evaluation of four signs using blinded analysis of 52 cases.

Four criteria have been described to differentiate ascites from pleural effusion by computed tomography (CT). These four signs (the diaphragm sign, the displaced crus sign, the interface sign, and the bare area sign) were compared in a retrospective blinded analysis in 52 patients with ascites, right pleural effusion, or both ascites and right pleural effusion. There were limitations with each of the four criteria. Each of the individual criteria was reliable when only one abnormal fluid collection, either pleural effusion or ascites, was present. When both a right pleural effusion and ascites were present, none of the four criteria reliably identified both fluid collections. The combined use of the four criteria, however, led to a correct identification of all the abnormal fluid collections.

Ascites↗