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Biomedical subjects

J V Rivera

Publications and source records attributed to J V Rivera.

At least 19 recordsLinked to original sources
PubMed1990

Gallium imaging of esophageal carcinoma: increased sensitivity with lateral views of the thorax.

Ga-67 imaging has not been very successful in the detection of esophageal carcinoma. In most reports, sensitivity for the primary tumor ranged from 25-61%, but imaging had been done only in anterior and posterior (A-P) projections. We performed gallium scans in 30 patients with esophageal carcinoma, adding lateral views to the routine A-P projections, to study the effect of lateral views on tumor detection. The A-P views detected only 57% of the tumors while the right lateral visualized 89%, and the left lateral detected 100%. Some lesions may be hidden by the sternum and the spine in the routine A-P views. Previous disappointments with Ga-67 imaging of esophageal carcinoma were probably due to this technical factor. Being gallium-avid, esophageal tumors deserve further studies with this agent to determine the role of Ga-67 imaging in this condition. These studies should be performed with multiple views of the thorax or, better yet, with SPECT imaging of the chest, to circumvent the problem of sternum and spine interference.

Adenocarcinoma↗
PubMed1988

Dual-tracer scintigraphy and subtraction studies in the diagnosis of hepatocellular carcinoma.

Dual tracer scintigraphy (DTS) (technetium 99m [99mTc] sulfur colloid and gallium 67 citrate [67 gallium citrate]) of the liver and computer subtraction studies (SS) were performed in 26 patients subsequently proven to have hepatocellular carcinoma (HCC) and 32 patients with cirrhosis and focal defects on the colloid scan, with no evidence for HCC after a complete evaluation and a 2-year follow-up period. Both DTS and SS had a sensitivity of 96% and a specificity of 90.6% for HCC. There were three false positive cases (9.4%), two of which were occult abscesses. The predictive value of a positive test was 89% and that of a negative test was 97%. The smallest tumor detected measured 2 cm in diameter and was only visualized with the SS. In the clinical setting, when HCC is suspected (a situation in which tumors are usually larger than 2 cm and the pretest probability of disease is between 20% and 60%) the DTS and SS is an excellent test for the diagnosis or exclusion of HCC. It does not appear to have a role in screening programs.

Carcinoma, Hepatocellular↗
PubMed1985

Gallium-67 localization in a mycotic aneurysm of the thoracic aorta.

Localization of Ga-67 in a mycotic aneurysm of the thoracic aorta in a renal transplant recipient is reported. This procedure complements other imaging methods in the diagnosis of this serious condition and may be preferable to In-111 leukocytes because of its ready availability.

Adult↗
PubMed1984

Radionuclide imaging of the liver in human fascioliasis.

The clinical, laboratory, and scintigraphic findings in four cases of human fascioliasis are described. Acute onset of fever, abdominal pain, and weight loss in a person who has ingested watercress constitutes the clinical syndrome often seen. Eosinophilia and alteration in liver function tests, particularly alkaline phosphatase are frequent. Tc-99m sulfur colloid images showed hepatomegaly in four patients, focal defects in two, splenomegaly in three, and increased splenic uptake in two. Gallium citrate (Ga 67) images show increased uptake in the focal lesions in two of two. Sonographic imaging showed focal lucent abnormality in one of three. Liver biopsy findings were nonspecific. The differential diagnosis from other invasive parasitic diseases is discussed. A possible role of hepatic imaging in the evaluation of fascioliasis is suggested.

Fascioliasis↗
PubMed1983

Altered anion handling by choroid plexus in renal insufficiency.

Abnormal localization of 99mTc pertechnetate was detected in the choroid plexus of patients with renal insufficiency despite the administration of potassium perchlorate. This was found in 8 of 21 studies on patients on conservative medical treatment, in 35 of 41 studies in patients on hemodialysis, in 12 of 22 studies in renal transplant recipients, and in 1 of 5 with acute renal insufficiency, but not in any of 33 persons free of renal disease. Abnormal retention of pertechnetate was also observed in the salivary glands of 21 renal patients. The increased localization of 99mTc pertechnetate could not be related to high blood levels of radioactivity, altered protein binding, increased erythrocyte labeling or to impaired gastrointestinal absorption of potassium perchlorate. It is proposed that this finding represents a manifestation of choroid plexus dysfunction resulting in altered handling of anions by this organ. A possible relation to neurological disease in chronic renal insufficiency is suggested.

Choroid Plexus↗