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Biomedical subjects

R L Baron

Publications and source records attributed to R L Baron.

132 records · Page 8Linked to original sources
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↗
PubMedDate not supplied

Detection of malignant primary hepatic neoplasms with gadobenate dimeglumine (Gd-BOPTA) enhanced T1-weighted hepatocyte phase MR imaging: results of off-site blinded review in a phase-II multicenter trial.

OBJECTIVE: To investigate the efficacy of gadobenate dimeglumine (Gd-BOPTA) enhanced MR imaging for the detection of liver lesions in patients with primary malignant hepatic neoplasms. MATERIALS AND METHODS: Thirty-one patients with histologically proven primary malignancy of the liver were evaluated before and after administration of Gd-BOPTA at dose 0.05 or 0.10 mmol/kg. T1-weighted spin echo (T1W-SE) and gradient echo (T1W-GRE) images were evaluated for lesion number, location, size and confidence by three off-site independent reviewers and the findings were compared to reference standard imaging (intraoperative ultrasound, computed tomography during arterial portography or lipiodol computed tomography). Results were analyzed for significance using a two-sided McNemar's test. RESULTS: More lesions were identified on Gd-BOPTA enhanced images than on unenhanced images and there was no significant difference in lesion detection between either concentration. The largest benefit was in detection of lesions under 1 cm in size (7 to 21, 9 to 15, 16 to 18 for reviewers A, B, C respectively). In 68% of the patients with more than one lesion, Gd-BOPTA increased the number of lesions detected. CONCLUSION: Liver MR imaging after Gd-BOPTA increases the detection of liver lesions in patients with primary malignant hepatic neoplasm.

Adenoma, Liver Cell↗
PubMedDate not supplied

Angiosarcoma. Diagnosis and clinical course.

The findings at radiography, computed tomography and angiography and the clinical course of 30 cases of angiosarcoma were reviewed. The variety of primary sites results in a multitude of findings but the most common finding was that of a hypervascular soft tissue mass seen on CT and angiography. Additional findings of well demarcated cortical defects in long bones were also frequently noted. The general clinical behavior of these aggressive malignant tumors was also reviewed and it was noted that they had a deceptively benign presentation.

Adult↗
PubMedDate not supplied

Dietary subacute toxicity of ethylene thiourea in the laboratory rat.

Ethylene thiourea (ETU) was fed to groups of rats at 0, 1, 5, 125 or 625 ppm for up to 90 days. Other groups of rats received either propylthiouracil (PTU; 125 ppm) or amitrole (50 ppm) in their diets as positive controls. Only those rats which received ETU at 125 or 625 ppm and those ingesting PTU or amitrole demonstrated a measurable toxic response. This toxicity was reflected as an alteration in thyroid function and a significant change in thyroid morphology. Ingestion of 625 ppm ETU or 125 ppm PTU resulted in very substantial decrease in serum triiodothyronine (T-3) and thyroxine (T-4). Marked increases in serum thyroid stimulating hormone (TSH) levels were found in the 625 and 125 ppm ETU rats, the 125 PTU rats, and the rats receiving amitrole, each time this hormone was measured. Rats which ingested 625 ppm ETU also exhibited a decrease in iodide uptake by the thyroid. While a statistically significant increase in serum T-4 and degree of thyroid hyperplasia was observed for rats ingesting 25 ppm ETU for 60 days, normal thyroid hormone levels and thyroid morphology was found in rats on 25 ppm ETU for either 30 or 90 days. Based on diochemical and microscopic changes examined, the no-effect level for dietary ETU in this 90-day study is considered to be 25 ppm.

Amitrole↗
PubMedDate not supplied

Hepatic perfusion: new perspectives at computed tomography.

The dual blood supply to the liver, that of hepatic arterial supply and portal venous blood supply represents both opportunity and trouble for radiologists in using contrast material to detect liver neoplasms. It is this unique feature that allows one to optimize tumor detection by optimizing contrast flow to either the liver parenchyma or to tumors. Conversely, however, if one does not optimize contrast administration to take advantage of differences in blood flow between liver parenchyma and liver neoplasms, potentially tumors can be obscured at imaging. The focus of this article will be to review the physiology of liver blood flow and how various methods of contrast material administration can be used to optimize CT liver tumor detection and characterization.

Hepatic Artery↗