Biomedical subjects

P M Berman

Publications and source records attributed to P M Berman.

15 recordsLinked to original sources

PubMed2001

MR imaging as the sole preoperative imaging modality for right hepatectomy: a prospective study of living adult-to-adult liver donor candidates.

OBJECTIVE: Our aim was to investigate the feasibility of MR imaging as a comprehensive preoperative imaging test for examination of liver donor candidates for adult-to-adult right lobe transplantation. SUBJECTS AND METHODS: Twenty-five consecutive donor candidates were examined at 1.5 T using a torso phased array coil with breath-hold T1- and T2-weighted imaging of the abdomen, MR cholangiography using T2-weighted turbo spin-echo imaging, and MR angiography and venography of the liver using two interpolated three-dimensional spoiled gradient-echo sequences (average dose of gadolinium contrast material, 0.17 mmol/kg). Images were interpreted for liver parenchymal and extrahepatic abnormalities; measurements of right and left lobe liver volumes; definition of hepatic arterial, portal venous, and hepatic venous anatomy; and definition of the biliary branching pattern. Findings were compared with those of conventional angiography in 13 patients, 11 of whom also had surgical findings for comparison. RESULTS: Nine patients were excluded as candidates for donation on the basis of MR imaging findings that included parenchymal or extrahepatic abnormalities in five patients, vascular anomalies in two, and biliary anomalies in three. Two patients who did not undergo surgery underwent conventional angiography that confirmed MR angiographic findings except for a small (<2 mm) accessory left hepatic artery missed on MR imaging. Of the nine patients who underwent successful right hepatectomy, all MR imaging findings were corroborated intraoperatively. In two patients, right hepatectomy was aborted at laparotomy because of intraoperative cholangiography findings; in one of them, the biliary finding was unsuspected on MR imaging. CONCLUSION: A comprehensive MR imaging examination has the potential to serve as the sole preoperative imaging modality for living adult-to-adult liver donor candidates provided improvements in definition of intrahepatic biliary anatomy can be achieved.

Adult↗

PubMed1995

Biliary tract: three-dimensional helical CT without cholangiographic contrast material.

Bile duct anatomy depicted with a three-dimensional (3D) model developed with helical computed tomography (CT) data was compared with cholangiographic depiction. The ductal system was completely displayed from all angles in four of six patients, as well as the stricture and length of bile duct between strictures and the bifurcation in five of six cases. 3D rendering can depict preoperative ductal anatomy.

Adult↗

PubMed1995

Abdominal aortic aneurysms: findings on three-dimensional display of helical CT data.

Excellent vascular opacification, reduction in misregistration artifacts, and the option of reconstructing overlapping scans from which three-dimensional (3D) models of the abdominal vessels may be rendered are among the benefits of helical CT [1-4]. The purpose of this essay is to illustrate the findings of 3D rendering of helical CT data in patients with abdominal aortic aneurysms.

Aortic Aneurysm, Abdominal↗

PubMed1995

Diagnosis of aortic dissection: value of helical CT with multiplanar reformation and three-dimensional rendering.

OBJECTIVE: Twenty-three patients with suspected aortic dissection were evaluated in this preliminary study of helical CT to determine the usefulness of axial sections, multiplanar reformation, and three-dimensional (3D) rendering in assessing the presence of dissection and the extent of intimal flap. MATERIALS AND METHODS: Patients were referred for helical CT scanning because of chest pain or an abnormal chest radiograph. Scans were performed during bolus injection of nonionic contrast material at 2.0-2.5 ml/sec using a mean scan delay of 47 sec. Axial scans with 5-mm collimation were obtained in all patients. They extended from the great vessels to the distal thoracic aorta just above the hiatus. Delayed nonhelical sections were obtained through the upper abdomen. Multiplanar reformations and 3D models were reconstructed from the helical data in 13 patients and were compared to axial sections in 7 patients who proved to have documented dissection. The efficacy of CT was determined using surgery, angiography, or clinical outcome to establish the diagnosis. RESULTS: Of the 23 patients studied, axial sections resulted in 15 true-negative, 7 true-positive, and 1 false-positive interpretation. In three of seven patients with dissection, it was difficult to determine the extent of the intimal flap on axial sections; multiplanar reformation or 3D views clarified the relevant anatomy in all 3 cases. Among the 3D display methods, ray-sum projection views were superior to surface model or maximum-intensity-projection views. CONCLUSION: If studies of larger numbers of patients confirm our preliminary findings, multiplanar reformation and 3D rendering of helical CT scans will be a valuable addition to axial display of CT studies used to detect aortic dissection and to determine the extent of the intimal flap.

Adult↗

PubMed1994

Abdominal aortic aneurysms: evaluation with variable-collimation helical CT and overlapping reconstruction.

PURPOSE: To determine the value of variable collimation and overlapping reconstruction in helical computed tomography (CT) to evaluate abdominal aortic aneurysm. MATERIALS AND METHODS: Twenty-three patients (15 men and eight women, aged 59-85 years) underwent helical CT scanning, nine with fixed 5-mm collimation and 14 with 3- and 7-mm collimation combined. The ability to visualize main and accessory renal arteries, detect stenoses, and determine aneurysm extent were evaluated. RESULTS: Extent of aneurysm was accurately determined in 17 of 23 cases without overlapping sections; failure to detect ancillary findings such as accessory arteries or stenosis occurred in nine of these cases. With overlapping sections, determination of aneurysm extent improved to 19 of 23 cases and ancillary errors were reduced to four. Five errors occurred with fixed collimation and three errors with variable collimation. CONCLUSION: Overlapping, variable-collimation helical CT allows for a more complete evaluation of abdominal aortic aneurysms than does nonoverlapping, fixed-collimation CT.

Aged↗

PubMed1986

Requirement for two or more Erwinia carotovora subsp. carotovora pectolytic gene products for maceration of potato tuber tissue by Escherichia coli.

Several genes encoding enzymes capable of degrading plant cell wall components have been cloned from Erwinia carotovora subsp. carotovora EC14. Plasmids containing cloned EC14 DNA mediate the production of endo-pectate lyases, exo-pectate lyase, endo-polygalacturonase, and cellulase(s). Escherichia coli strains containing one of these plasmids or combinations of two plasmids were tested for their ability to macerate potato tuber slices. Only one E. coli strain, containing two plasmids that encode endo-pectate lyases, exo-pectate lyase, and endo-polygalacturonase, caused limited maceration. The pectolytic proteins associated with one of these plasmids, pDR1, have been described previously (D. P. Roberts, P. M. Berman, C. Allen, V. K. Stromberg, G. H. Lacy, and M. S. Mount, Can. J. Plant Pathol. 8:17-27, 1986) and include two secreted endo-pectate lyases. The second plasmid, pDR30, contains a 2.1-kilobase EC14 DNA insert that mediates the production of an exo-pectate lyase and an endo-polygalacturonase. These enzymes are similar in physicochemical properties to those produced by EC14. Our results suggest that the concerted activities of endo-pectate lyases with endo-polygalacturonase or exo-pectate lyase or both cause maceration.

Cell Wall↗

PubMed1974