Search PubMed⌕ Search

Biomedical subjects

R L Baron

Publications and source records attributed to R L Baron.

At least 127 records · Page 7Linked to original sources
PubMed1981

Mesenteric desmoid tumors: sonographic and computed-tomographic appearance.

Sonographic and computed-tomographic (CT) findings in two patients with mesenteric desmoid tumors are reviewed. On ultrasound scans, mesenteric desmoids appear as well-circumscribed masses with scattered dense high-level echoes which correspond to mesenteric fat and vessels on the CT scan. Although these tumors appear well marginated on both ultrasound and CT scans, the pathologic examination shows microscopic invasion at the tumor margin in most cases. Differentiation from other mesenteric masses is discussed.

Adult↗
PubMed1981

Clinical and radiographic manifestations of aortoesophageal fistulas.

Aneurysms of the thoracic aorta simulated primary esophageal disease both clinically and radiographically in 5 patients. Four had an aortoesophageal fistula at the time of presentation; endoscopic biopsy of a presumed esophageal tumor precipitated hematemesis in the fifth patient. In retrospect, the fistulas were demonstrated by barium esophagography in 3 patients. In 3, arteriography showed the aortic aneurysm but failed to reveal the fistula. The literature confirms a similar presentation for most other aortoesophageal fistulas, with premonitory esophageal bleeding followed hours to days later by massive hemorrhage. Of the reported cases of rupture of aneurysms of the thoracic aorta, 12% bled into the esophagus. While clinical and radiographic distinction between primary esophageal disease and esophageal manifestations of an aortic aneurysm is occasionally difficult, it is crucial for proper management.

Aged↗
PubMed1981

Intrathoracic extension of retroperitoneal urine collections.

Five patients with retroperitoneal urine collections (urinomas) had clinical and radiographic evidence of intrathoracic disease. All five patients rapidly accumulated pleural fluid, documented chemically in three patients to be urine. Two patients developed acute mediastinal widening which rapidly cleared after surgical drainage of the retroperitoneal urinoma. Although rare, thoracic collections of urine should be considered when pleural effusions or mediastinal widening occur in patients with urinary tract obstruction or retroperitoneal urinomas.

Aged↗
PubMed1981

CT of anomalies of the mediastinal vessels.

Computed tomographic (CT) studies of the thorax were performed on 12 patients with congenital anomalies of the mediastinal great vessels. CT correctly identified 11 of 12 abnormalities including left superior vena cava, right aortic arch with aberrant left subclavian artery, L- and D-transposition of the great vessels, pulmonary valvular stenosis, and truncus arteriosus. CT obviated further invasive procedures in those anomalies not associated with intracardiac defects and supplemented the angiographic findings in some patients with intracardiac defects requiring catheterization.

Adolescent↗
PubMed1980

Developmental toxicity of guthion in rats and mice.

The purpose of this study was to assess the effects of Guthion, a pesticide with anticholinesterase activity, on development in rats and mice. A preliminary toxicity study with Guthion indicated that a 35-day LD50 dose for virgin rats and a 10-day LD50 dose for virgin mice was between 4 and 8 mg/kg/day for both species. On the basis of these data, doses of 0, 1.25, 2.5, and 5.0 mg/kg/day were selected for the developmental study, which consisted of two phases. During the first phase, pregnant rats and mice were treated for 10 days starting on gestational day 6. The high dose affected maternal welfare only in rats. Guthion did not significantly increase in a dose-related manner any of the specific anomalies observed in either rats or mice. During the second phase, pregnant rats were treated from gestational day 6 to postpartum day 21. Dams in the high dose group were more sensitive to Guthion later in gestation with the result that deaths and signs of anticholinesterase toxicity increased during this time. Guthion also adversely affected maternal welfare in this group. As a result of Guthion toxicity, only one litter survived until weaning. The inability to dissociate toxicity in adult and developing animals suggests that Guthion has little primary effect on the development of rats or mice.

Abnormalities, Drug-Induced↗
PubMedDate not supplied

Gadobenate dimeglumine (BOPTA) enhanced MR imaging: patterns of enhancement in normal liver and cirrhosis.

To determine whether gadobenate dimeglumine (BOPTA) will adequately enhance cirrhotic liver parenchyma, and to document the enhancement patterns in cirrhosis, 14 cirrhotic and 20 non-cirrhotic patients were evaluated before and 60-120 minutes after gadolinium-BOPTA. Proof of liver cirrhosis was biopsy (6), surgical resection (3), and clinical follow-up (5). Enhancement effects were compared quantitatively by determining the liver signal-to-noise ratio (SNR) and signal enhancement in both populations. Qualitatively assessment of the liver enhancement was performed and classified as homogeneous or heterogeneous. Quantitative analysis: cirrhotic liver parenchyma presented a higher increase in SNR values, relative to non-cirrhotic liver parenchyma, on postcontrast images. Likewise the signal enhancement of cirrhotic liver parenchyma was superior to non-cirrhotic liver on T1-weighted SE images (P = .02) and in-phase GRE images (P < .001). There was no statistical difference on out-of-phase GRE images. Qualitative analysis: on T1-weighted SE postcontrast images, cirrhotic liver parenchyma showed a homogeneous enhancement in 7 patients and heterogeneous in 7. Whereas on GRE images, cirrhotic parenchyma showed heterogeneous enhancement in 9 patients and homogeneous in 5 patients. The heterogeneous enhancement was due to the presence of hypointense nodules in 7 patients and hyperintense nodules in 2 patients. In conclusion, our study has shown that the hepatobiliary contrast agent Gd-BOPTA is effective in the cirrhotic liver, demonstrating an increased liver enhancement compared with non-cirrhotic patients.

Aged↗
PubMedDate not supplied

MR imaging patterns of gadolinium retention within liver neoplasms.

BACKGROUND: To determine the spectrum of appearances of gadolinium retention within cholangiocarcinoma (CCA) and other liver neoplasms. METHODS: Two hundred ten patients underwent hepatic magnetic resonance imaging (MRI) at 1.5 T with precontrast T1- and T2-weighted spin-echo (SE) images and delayed Gd-DTPA- or gadoteridol- (0.1 mmol/kg) enhanced T1-weighted SE images. Postcontrast images were evaluated for lesions suspicious for tumors, and lesion signal intensity was characterized as homogeneously or heterogeneously hypo-, iso-, mildly hyper-, or markedly hyperintense to liver. Data from 94 patients with benign or malignant neoplasms are presented. RESULTS: Imaging demonstrated 237 malignant neoplasms (121 hepatocellular carcinoma [HCC], 26 CCA, 17 colon carcinoma metastases, 73 other tumors) and 28 benign neoplasms (22 hemangioma, six focal nodular hyperplasia [FNH]). One hundred forty malignant lesions appeared as homogeneous postcontrast (29 hypointense, 75 isointense, 17 mildly hyperintense, 19 markedly hyperintense) and 97 as heterogeneous (15 isointense, 50 mildly hyperintense, 32 markedly hyperintense). Malignant lesions showing homogeneous, mildly or markedly hyperintense signal intensity postcontrast included 10 CCA, seven HCC, six epithelioid hemangioendothelioma, eight neuroendocrine tumor metastases, three adenocarcinoma metastases of unknown origin, and one breast carcinoma metastasis. Hemangiomas appeared as homogeneous postcontrast in 19 lesions (six isointense, one mildly hyperintense, 12 markedly hyperintense) and as heterogeneous in three lesions (markedly hyperintense). FNH appeared as homogeneous postcontrast in one lesion (isointense) and as heterogeneous in five lesions (one isointense, four mildly hyperintense). CONCLUSION: Homogeneous gadolinium retention on delayed postcontrast images of malignant hepatic neoplasms is seen in a high percentage of CCA lesions and less commonly with other neoplasms.

Contrast Media↗