Biomedical subjects

S J Schulte

Publications and source records attributed to S J Schulte.

7 recordsLinked to original sources

PubMed1992

Patterns of intrahepatic bile duct dilatation at CT: correlation with obstructive disease processes.

The authors performed a blinded, retrospective analysis of 100 computed tomographic (CT) scans of patients with proved extrahepatic bile duct obstruction, including primary sclerosing cholangitis (PSC), to determine whether certain patterns of intrahepatic bile duct dilatation are suggestive of specific disease processes. Among 30 patients with benign obstructive disease, CT showed pruning of the intrahepatic ducts in four patients (13%), beading in four (13%), and skip dilatations in one (3%). Among 54 patients with malignant obstructive disease, CT illustrated pruning in eight (15%) patients, beading in 11 (20%), and skip dilatations in two (4%). Among 16 patients with PSC, CT demonstrated pruning in four (25%), beading in two (13%), and skip dilatations in five (31%). The majority of patients with malignant or benign obstructive disease or PSC had intrahepatic duct dilatation in both lobes of the liver. It extended into the periphery in 46 of 54 patients (85%) with malignant obstructive disease, in 20 of 30 (67%) with benign obstructive disease, and in 10 of 16 (63%) with PSC. The CT finding of skip dilatations is strongly suggestive of PSC. The CT findings of pruning and beading are nonspecific and may be observed at CT in patients with bile duct obstruction due to a wide variety of causes. The distribution and extent of intrahepatic duct dilatation at CT do not differ among biliary disease processes.

Bile Duct Neoplasms↗

PubMed1991

Root of the superior mesenteric artery in pancreatitis and pancreatic carcinoma: evaluation with CT.

To determine if changes involving the root of the superior mesenteric artery are specific for neoplasm, the authors retrospectively reviewed 173 computed tomographic (CT) examinations of patients with proved pancreatitis (103 examinations) and pancreatic ductal adenocarcinoma (70 examinations). Streaky infiltration of the fat surrounding the root was seen in 27 of 56 examinations of acute pancreatitis, in four of 24 examinations of chronic pancreatitis, in 12 of 23 examinations of pancreatitis complicated by abscess, and in 25 of 70 examinations of pancreatic carcinoma. Periarterial lymph nodes were visible in 14 with acute pancreatitis, in three with chronic pancreatitis, in six with pancreatic abscess, and in 11 with pancreatic carcinoma. A focal mass extended to within 1 cm of the root in 10 with acute pancreatitis, in two with chronic pancreatitis, in four with pancreatic abscess, and in 24 with pancreatic carcinoma; the mass obliterated the periarterial fat in seven with acute pancreatitis, in one with pancreatic abscess, and in 18 with pancreatic carcinoma. Circumferential encasement occurred in one with chronic pancreatitis, in four with pancreatic abscess, in 14 with pancreatic carcinoma, and in none with acute pancreatitis; nearly all cases of encasement revealed loss of periarterial fat. Thus, these indicators are not specific for neoplasm.

Abscess↗

PubMed1990

Differentiating pelvic veins and enlarged lymph nodes: optimal CT techniques.

A study was done to find the best technique of administering contrast material intravenously to enable differentiation of pelvic veins and enlarged lymph nodes on computed tomographic (CT) scans. Seventy-eight patients with suspected pelvic malignancies were evaluated with CT. After precontrast scans were obtained at a selected pelvic level, 150 mL of contrast material was injected as a two-phase bolus; images were obtained at the same level 1.5, 3, 5, and 7 minutes after initiation of the bolus. Mean pelvic venous enhancement was maximal between 3 and 7 minutes in all the patients. Venous attenuation changes did not correlate with the presence of cardiac or peripheral vascular disease, but there was significantly less enhancement in patients with diabetes mellitus. The time of maximum vein enhancement begins at 3 minutes and continues for at least 4 minutes. A delayed technique of scanning the pelvis may be preferable to rapid scanning to optimize enhancement of the pelvic veins.

Adult↗

PubMed1990

CT of the extrahepatic bile ducts: wall thickness and contrast enhancement in normal and abnormal ducts.

Recent reports have described thickening and enhancement of the extrahepatic bile duct wall on CT scans obtained after administration of IV contrast material. We undertook this study to establish parameters for the normal thickness and enhancement of the bile duct wall on CT, and to develop a differential diagnosis for thickening of the duct wall. Routine CT examinations of 100 patients without biliary disease were evaluated prospectively. The common hepatic duct and common bile duct could be visualized in 66% and 82% of cases, respectively; the walls of these ducts could be separately discerned in 59% and 52%. The mean thickness of the duct wall was 1 mm, with a maximal thickness of 1.5 mm. Wall enhancement was similar to (51%), slightly greater than (44%), or markedly greater than (5%) the enhancement of adjacent pancreatic parenchyma. A review of records covering a 5-year period identified 52 patients in whom CT showed thickening of the bile duct wall (greater than or equal to 2 mm). These patients could be categorized by seven underlying diseases, and analysis of the CT scans revealed four general patterns of thickening. Focal, concentric wall thickening in the distal common bile duct was associated with pancreatitis, pancreatic cancer, and common bile duct stones; focal, eccentric thickening tended to occur with cholangiocarcinoma and sclerosing cholangitis. Diffuse, concentric thickening was seen with acute cholangitis; diffuse, eccentric thickening was associated with oriental cholangiohepatitis and sclerosing cholangitis. Thickening of greater than 5 mm was seen only with cholangiocarcinoma. Enhancement of the duct wall in these groups varied and was of no predictive value. In summary, the extrahepatic bile ducts can be visualized in the majority of patients, and the normal duct wall should be 1.5 mm or less in thickness. Contrast enhancement of the duct wall occurs in patients without biliary tract disease and alone is predictive not predictive of pathology. Pancreatitis, pancreatic cancer, common bile duct stones, cholangiocarcinoma, sclerosing cholangitis, acute cholangitis, and oriental cholangiohepatitis are associated with thickening of the duct wall.

Acute Disease↗

PubMed1990

Piezoelectric biliary lithotripsy: an in vitro study of factors affecting gallstone fragmentation.

Factors affecting the fragmentation of gallstones with piezoelectric lithotripsy were studied in vitro, with a goal of providing data that will help direct treatment with piezoelectric lithotriptors. Two hundred fifty-seven stones from 50 patients were treated with the EDAP LT.O1 lithotriptor until all fragments measured 2 mm or less in diameter. The fragmentation process was observed, and two patterns were evident: central fragmentation and peripheral chipping. The majority of stones fragmented centrally. Fragmentation characteristics in different stones from the same patient were compared with those from different patients. Stone diameter, shock-wave frequency and power, and CT appearance were examined and correlated with fragmentation. Gallstones from the same patient showed uniform fragmentation patterns and consistent relationships between fragmentation time and gallstone size, shock-wave frequency, and power. In stones from the same patient, gallstone size had a marked effect on fragmentation time, which correlated with the cube of the stone diameter, and shock-wave frequency and power had a proportional inverse linear relationship with fragmentation time. When controlling for stone size and treatment parameters, stones from multiple patients showed marked differences in fragmentation time, and because of this, poor correlation between stone size and fragmentation time. Stones grouped according to CT pattern and attenuation showed wide variation and no correlation between CT characteristics and fragmentation pattern or fragmentation time. Our results show that a great variability exists in fragmentation time of gallstones, making it impossible to accurately predict fragmentation time at a given stone size. Only rough estimates of longer fragmentation times with increasing stone size can be made. The linear relationships between shock-wave frequency or power and fragmentation time allow one to easily predict the effect of manipulating these variables and to tailor treatment to each patient's tolerance. Finally, CT appearance does not appear to be predictive of fragmentation outcome.

Biomechanical Phenomena↗

PubMed1987

Nuclear disaster.

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Animal Feed↗

PubMedDate not supplied

Mechanical lithotripsy of large gallstones: correlation with CT characteristics.

The CT characteristics of gallstones were correlated with mechanical forces required to fragment calculi in vitro. Forty-two gallstones > or = 11 mm in largest diameter were subjected to in vitro CT scanning and categorized as isodense, faint, laminated, rimmed, or dense as compared with saline. A mechanical lithotripter, attached to a dynamometer, was utilized simulating in vivo technique to accomplish lithotripsy. Significantly more force was required to fracture CT-dense (p < 0.02) and CT-rimmed (p < 0.05) gallstones than was required to fracture CT-isodense gallstones.

Gallstones↗