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Biomedical subjects

B A Birnbaum

Publications and source records attributed to B A Birnbaum.

54 records · Page 3Linked to original sources
PubMed1991

Appendicitis: prospective evaluation with high-resolution CT.

Computed tomography (CT) was used to prospectively evaluate 100 patients with clinical indications for acute appendicitis. Examinations were performed with the terminal ileum and cecum filled with contrast material. Acute appendicitis was diagnosed when an abnormal appendix or inflammatory changes plus an appendicolith were detected. Failure to visualize an abnormal appendix or appendicolith in the presence of pericecal inflammatory changes was considered suspicious but nonspecific. CT results were correlated with surgical and pathologic results (74 patients) and other radiologic and clinical findings (26 patients). CT helped to diagnose appendicitis (64 patients) and nonspecific right lower quadrant inflammation (five patients) and to rule out appendicitis (31 patients). CT had a 98% sensitivity, an 83% specificity, and a 93% accuracy. In 17 of 31 patients without CT evidence of appendicitis, other conditions explaining their symptoms were detected. When the clinical diagnosis is in doubt, CT can be used successfully to evaluate patients with acute appendicitis.

Acute Disease↗
PubMed1991

Renal lesion characterization with gadolinium-enhanced MR imaging: efficacy and safety in patients with renal insufficiency.

Five patients with renal insufficiency were studied with T1-weighted magnetic resonance (MR) imaging before and after intravenous administration of gadopentetate dimeglumine (0.1 mmol/kg) to characterize renal lesions that were detected with nonenhanced computed tomography (CT) and were considered indeterminate. Four patients demonstrated renal lesions that enhanced after gadolinium administration. A total of five lesions in these four patients were surgically resected and found to be renal cell carcinoma at pathologic examination. The fifth patient was spared surgery because a hyperattenuated lesion noted at nonenhanced CT did not enhance with intravenous gadolinium, indicating a benign cyst. Five incidentally occurring benign cysts removed at the time of nephrectomy in two of the patients did not demonstrate enhancement with gadolinium on MR images. Serial serum creatine levels were obtained before and after gadolinium administration in all patients; no changes were noted after gadolinium administration. Gadolinium-enhanced MR imaging is an effective method for characterizing renal lesions in patients with renal insufficiency. At the usual dosage, there appears to be no nephrotoxic reaction in these patients.

Aged↗
PubMed1991

Bowel obstruction: evaluation with CT.

Eighty-four computed tomographic (CT) scans from patients referred for bowel obstruction between January 2, 1988, and December 31, 1989, were retrospectively evaluated. A pair of radiologists without knowledge of patient histories determined the presence or absence of bowel obstruction. Sixty-four patients ultimately proved to have intestinal obstruction, and 20 did not. Diagnosis was established by means of surgery (n = 39), barium studies (n = 17), and clinical course (n = 28). Causes of obstruction included adhesions (n = 37), metastases (n = 6), primary tumor (n = 7), Crohn disease (n = 4), hernia (n = 3), hematoma (n = 2), colonic diverticulitis (n = 2), and other (n = 3). In addition, 83 CT examinations in patients with no history or indication of intestinal obstruction were simultaneously reviewed. The overall sensitivity was 94%, specificity was 96%, and accuracy was 95%. The cause of obstruction was correctly predicted in 47 of 64 cases (73%). Intestinal obstruction was not diagnosed in any of the 83 control patients. CT is most useful in patients with a history of abdominal malignancy and in patients who have not been operated on and who have signs of infection, bowel infarction, or a palpable abdominal mass.

Barium Sulfate↗
PubMed1991

Hepatic hemangiomas: diagnosis with fusion of MR, CT, and Tc-99m-labeled red blood cell SPECT images.

A method of image analysis was developed for correlation of hemangiomas detected at computed tomography (CT) and/or magnetic resonance (MR) imaging with increased blood pool activity evident at single photon emission CT (SPECT) performed after labeling of red blood cells with technetium-99m. Image analysis was performed in 20 patients with 35 known hepatic hemangiomas. After section thickness and pixel sizes of the different studies were matched, intrinsic landmarks were chosen to identify anatomically corresponding locations. Regions of interest (ROIs) drawn on the CT and/or MR images were translated, rotated, and reprojected to match the areas of interest on the corresponding SPECT images by means of a two-dimensional polynomial-based warping algorithm. Analysis of ROIs on 30 SPECT-MR and 20 SPECT-CT pairs of registered images provided absolute confirmation that 34 suspected hemangiomas identified on SPECT images correlated exactly with lesions seen on CT and/or MR images. Accuracy of fusion was within an average of 1.5 pixels +/- 0.8 (+/- 1 standard deviation). The technique enabled diagnostic confirmation of hemangiomas as small as 1.0 cm and proved useful for evaluating lesions located adjacent to intrahepatic vessels.

Adult↗
PubMed1990

Extrapulmonary Pneumocystis carinii infection in AIDS: CT findings.

Clinical and computed tomographic (CT) findings in three cases of extrapulmonary Pneumocystis carinii infection in patients with acquired immunodeficiency syndrome (AIDS) were reviewed. Proved sites of involvement included the spleen (n = 2), bone marrow (n = 1), liver (n = 1), and peritoneal and pleural fluid (n = 1). CT findings included focal low-attenuation splenic lesions that became progressively calcified in rimlike or punctate fashion; punctate calcifications in the liver, renal cortices, and adrenal glands; calcification of lymph nodes; and pleural and peritoneal effusions with subsequent calcifications of the pleural and peritoneal surfaces. Although rare both before and since the onset of the AIDS epidemic, extrapulmonary P carinii infection in AIDS patients has been reported with increasing frequency in recent years, and more cases with radiologic manifestations should be expected.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Definitive diagnosis of hepatic hemangiomas: MR imaging versus Tc-99m-labeled red blood cell SPECT.

Thirty-seven patients with 69 suspected hemangiomas found by means of computed tomography (CT) and/or ultrasound were studied with both 0.5-T magnetic resonance (MR) imaging and single photon emission CT (SPECT) with technetium-99m-labeled red blood cells. Using a criterion of "perfusion-blood pool mismatch," SPECT readers diagnosed 50 of 64 hemangiomas and all five "nonhemangiomas" (sensitivity, 78% [95% confidence interval, 0.664 - 0.864]; accuracy, 80% [0.69 - 0.877]). Qualitative analysis of lesion signal intensity on T2-weighted spin-echo MR images allowed readers to diagnose 58 of 64 hemangiomas and four of five nonhemangiomas (sensitivity, 91% [0.814 - 0.96]; accuracy, 90% [0.807 - 0.951]). Because of the significantly higher cost of MR imaging and its inability to categorically differentiate hemangiomas from hypervascular metastases, the authors consider SPECT to be the method of choice for diagnosing hepatic hemangiomas. MR imaging should be reserved for the diagnosis of lesions smaller than 2.0 cm and for those 2.5 cm and smaller adjacent to the heart or major hepatic vessels; in such cases MR imaging was found superior to SPECT.

Adult↗
PubMed1990

Observations on the growth of renal neoplasms.

A retrospective review of the imaging results of 11 patients with 13 solid renal parenchymal neoplasms was performed, allowing analysis of the linear growth rates of these tumors. The study sample included seven pathologically proved renal adenocarcinomas and six lesions that were indicative of a neoplasm radiologically (enhancing parenchymal mass on computed tomographic [CT] scans with documented interval growth), which were followed up for 2-7.8 years. Variable interval tumor growth was demonstrated in every case except one and ranged from 0 to 1.6 cm/y, with an overall mean linear growth rate of approximately 0.5 cm/y. Ten of 11 "small renal neoplasms" (less than or equal to 3.0 cm in diameter) displayed interval growth, with five ultimately measuring greater than 3.0 cm (size range, 3.5-7.0 cm). While the results are preliminary and reflect observations on a very small study sample, it was noted that five of the seven pathologically proved adenocarcinomas appeared homogeneous and well marginated, and all were low-grade, low-stage carcinomas. These grew more slowly and were generally smaller at initial presentation than higher-grade lesions, which demonstrated a more heterogeneous appearance on CT scans.

Carcinoma, Renal Cell↗
PubMedDate not supplied

Renal cell carcinoma: correlation of CT findings with nuclear morphologic grading in 100 tumors.

The contrast-enhanced preoperative computed tomographic (CT) scans and microscopic slides of 94 patients with 100 surgically resected renal cell carcinomas (RCCs) were retrospectively and independently reviewed in order to correlate the CT imaging findings of RCC with nuclear grading. As nuclear grade increased, RCCs were more likely to be of higher stage and greater size at presentation, and appeared more heterogeneous and less marginated. Of the features analyzed, tumor margination most closely correlated with nuclear grade. Overlap in the CT appearance of individual tumors limited the potential of CT to differentiate RCCs of varying grade. Small, well-marginated, homogeneous tumors, however, were either grade I or II, and were distinguishable from the more aggressive grade III lesions, which generally displayed irregular margins and greater inhomogeneity.

Adult↗
PubMedDate not supplied

Abdominal visceral calcification in primary amyloidosis: CT findings.

The computed tomographic (CT) findings of extensive visceral calcification involving both the liver and spleen in a patient with primary amyloidosis are presented. Although the CT imaging appearances of amyloidosis are often nonspecific, visceral calcification represents an important diagnostic clue for differentiating this entity from other infiltrative parenchymal diseases.

Adult↗
PubMedDate not supplied

Comparison of contrast enhanced CT and Mn-DPDP enhanced MRI for detection of focal hepatic lesions. Initial findings.

Twenty-nine patients with known or suspected focal hepatic disease were evaluated in a retrospective multi-institutional study comparing T1-weighted manganese (II) N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5,5'-bis (phosphate) (DPDP) enhanced magnetic resonance imaging (MRI) with dynamic sequential bolus contrast enhanced computed tomography (DBCT) for the detection of focal liver lesions. The patients were divided into four dose groups, receiving 3, 5, 8, or 10 mumol/kg of Mn-DPDP, delivered either via intravenous bolus (0.25 ml/sec) or infusion (1 ml/sec). Each of three readers, with varying levels of expertise in interpreting hepatic MRI and CT studies, identified more lesions on the Mn-DPDP enhanced MRI than the contrast enhanced CT images. Mn-DPDP enhanced MRI depicted the presence of extensive metastatic disease not seen with DBCT in three patients with fatty liver. The most experienced MRI reader saw more lesions per patient on the Mn-DPDP enhanced MRI than with DBCT, while the opposite held true for the most experienced CT reader. The best single exam for detection of hepatic lesions may be determined by the experience of the reader.

Adolescent↗
PubMedDate not supplied

Omental caking in Hodgkin's disease. Computed tomography findings.

Neoplastic infiltration of the greater omentum is most commonly caused by metastatic ovarian, gastric, colonic, or pancreatic carcinoma. Because the omentum lacks lymphoid elements, lymphomatous infiltration is uncommon. To date, omental involvement by lymphoma has been reported exclusively in patients with non-Hodgkin's lymphomas. In this report, the computed tomography findings of omental caking caused by Hodgkin's lymphoma are described. Although rare, both Hodgkin's and non-Hodgkin's lymphomas should be included in the differential diagnosis of omental caking.

Diagnosis, Differential↗
PubMedDate not supplied

Omental infarction as a delayed complication of abdominal surgery.

Omental infarction, an uncommon cause of acute abdominal pain, is the result of compromised perfusion to the greater omentum. Although its etiology remains uncertain, predisposing factors include obesity [Surg. Today 30 (2000) 451], strenuous activity [N. Z. Med. J. 111 (1998) 211], trauma, and idiopathic omental torsion. Often confused with acute appendicitis or cholecystitis on clinical grounds [Surg. Today 30 (2000) 451], its diagnosis has traditionally been one of exclusion, based on intraoperative and pathologic findings. This diagnosis can be made radiologically based on the characteristic findings of an inflammatory mass containing fat and fluid. We describe a case of right lower quadrant omental infarction temporally related to bowel surgery.

Abdomen, Acute↗
PubMedDate not supplied

Acute cholangitis: CT evaluation.

The CT findings of 23 patients with proven acute ascending cholangitis were retrospectively evaluated. Computed tomography confirmed the clinical diagnosis and detected the site and etiology of the obstructive process in the majority of patients. Biliary dilatation consistent with the clinical suspicion of acute cholangitis was present in 18 patients (78%), the level of the obstruction was detected in 15 patients, and the etiology of the obstructive process was visualized in 14 cases. Five patients presented with air in the biliary tree and three patients had liver abscesses. There was no good correlation established between jaundice, biliary infection, and the presence or degree of biliary dilatation. Biliary obstruction and acute cholangitis can develop before biliary dilatation is detected. In addition, CT showed limitations in establishing the etiology of the obstructive process, particularly in failing to detect 7 of 17 cases of cholesterol biliary stones.

Acute Disease↗
PubMedDate not supplied

The costs of CT procedures in an academic radiology department determined by an activity-based costing (ABC) method.

PURPOSE: The purpose of this work was to determine the costs of computed tomography (CT) procedures in a large academic radiology department, including both professional (PC) and technical (TC) components, by analyzing actual resource consumption using an activity-based costing (ABC) method and comparing them with Medicare payments. METHOD: Over a 12 month period from July 1, 1996, to June 30, 1997, 1,011 CT procedures, representing 16 Physicians' Current Procedural Terminology (CPT) codes and 98.3% of CT studies performed, were carefully observed by a research assistant trained in ABC methodology. Information collected during these time and motion studies included personnel/machine time and direct materials used. Actual resource units used during the different activities in each CT procedure were valued using appropriate cost drivers. Unit values for both direct and overhead costs were calculated: the cost of an individual procedure equaled the sum of component costs. Costs were compared with PC and TC payments according to the 1997 Medicare Fee Schedule. RESULTS: Total costs of CPT codes 70450 (CT Head unenhanced), 71260 (CT Chest enhanced), and 74160 (CT Abdomen enhanced), which represented 71.2% of CT studies performed, were $189.19, $273.53, and $343.20, respectively. For all 16 nonmodified CPT codes analyzed, Medicare's professional reimbursement was less than the professional cost, whereas its technical reimbursement exceeded respective cost in 14 of the 16 codes. CONCLUSION: In the setting and time period studied, Medicare underreimbursed professional costs while overreimbursing technical costs.

Academic Medical Centers↗