Gary G. Winzelberg

Detection of gastrointestinal bleeding with 99mTc-labeled red blood cells

Using a modified in vivo Tc-99M red cell labeling technique, gastrointestinal bleeding scintigraphy was performed in 100 patients with GI bleeding. Sixty-two patients with melena or bright red blood per rectum had positive scintiscans. In comparison to results of angiography, endoscopy, surgery and contrast radiography, radionuclide scintigraphy correctly located the site of bleeding in 83% of patients. The procedures could be performed over a 24 hr period which increased the sensitivity of the test since 85% of the scintiscans were positive at one hr or greater after the onset of imaging. The procedure was more sensitive than angiography in detecting sources of GI bleeding. We conclude that GI bleeding scintigraphy 99mTc-red cells in an accurate and effective method to detect upper and lower GI bleeding in patients with acute intermittent gastrointestinal bleeding.

Indium‐111 monoclonal antibody b72.3 scintigraphy in colorectal cancer correlation with computed tomography, surgery, histopathology, immunohistology, and human immune response

As part of an open‐labeled nonrandomized multi‐institutional Phase III study, the authors compared the results of In‐111 (In‐111) B72.3 glycyl‐tyrosyl‐n‐diethylenetri‐aminepentaacetic acid lysine (GYK‐DTPA) monoclonal antibody scintigraphy with computed tomography (CT), surgery, histopathology, immunohistology, and human antibody response in 23 patients with primary colorectal carcinoma. There were no significant adverse reactions to 1 mg of In‐111‐labeled antibody. Planar imaging identified 16 of 23 primary colon lesions, whereas single photon emission computer tomography (SPECT) imaging identified 21. SPECT also correctly identified lymphatic involvement in four patients. (There were two false‐positive results.) Liver metastases were identified with SPECT imaging. Twenty‐six percent of patients developed human anti‐mouse antibody (HAMA). These preliminary results demonstrate that In‐111 B72.3 GYK‐DTPA is a safe monoclonal antibody conjugate that has a high sensitivity for identifying primary colorectal cancer. Regional lymphatic and distant liver metastases also can be imaged, but false‐positive results can occur.

Radionuclide imaging of parathyroid tumors: Historical perspectives and newer techniques

The increasing use of automated blood chemistry screens for serum calcium levels along with improved methods in measuring parathyroid hormone (PTH) levels have made the diagnosis of parathyroid disease a common clinical problem. Parathyroid adenomas account for the majority of primary hyperparathyroidism with diffuse hyperplasia and parathyroid carcinoma occurring less frequently. Early scintigraphic techniques to identify enlarged parathyroids used selenomethionine-75 which was considered to be incorporated into PTH. In general, the sensitivity of scanning the neck using this tracer was related to the size of the enlarged parathyroid, but in large series, the overall sensitivity was less than 50%. Recent work by Ferlin et al, using a Technetium-99m/Thallium-201 subtraction scintigraphic technique has yielded a sensitivity of 92% in identifying pathologically enlarged parathyroid glands. Winzelberg et al modified this technique to allow imaging the mediastinum plus simplifying the subtraction method. In a prospective study with high-resolution sonography, similar sensitivities and specificities were found with sonography and scintigraphy. Tl-201/Tc-99m pertechnetate subtraction scintigraphy appears to be an accurate technique in identifying pathologic parathyroid enlargement. Its ultimate role in the evaluation of patients with suspected hyperparathyroidism still needs to be determined.

Scintigraphic evaluation of left ventricular aneurysm

Gated cardiac blood pool scintigraphy is a noninvasive method to assess regional and global left ventricular function in the patient with suspected true or false left ventricular aneurysm after a myocardial infarction. The procedure is easy to perform and provides reproducible, high resolution images that can accurately distinguish from diffuse contractile abnormalities often present after myocardial infarction. An overall accuracy rate of 96 percent for detection of left ventricular aneurysm can be obtained with gated cardiac blood pool scintigraphy as compared with contrast left ventriculography. The procedure also permits assessment of functional reserve of the noninvolved myocardium and thus can provide valuable information on whether enough viable myocardium will remain after aneurysmectomy. The addition of thallium-201 myocardial perfusion scintigraphy may aid in the separation of viable from scarred myocardium at the edge of the aneurysm. Both radionuclide techniques are well suited for screening the patient after infarction with persistent congestive heart failure, malignant arrhythmia or systemic emboli in whom a left ventricular aneurysm may have developed.

Retinitis pigmentosa and colon cancer. A previously unreported association

Retinitis pigmentosa, a hereditary disease characterized by progressive retinal degeneration and blindness, has been associated with numerous diseases. We report the first association between retinitis pigmentosa and colon cancer in 3 of 53 hospitalized patients with retinitis pigmentosa at the Massachusetts General Hospital and Massachusetts Eye and Ear Infirmary for the period from 1962 to 1977.

Focal gallium uptake in the liver.

A 67-year-old man was admitted to the hospital with weight loss and abdominal pain. On physical examination, the liver was enlarged and tender. Laboratory studies demonstrated a mild elevation of the SGOT and SGPT with moderate elevation of the alkaline phosphatase. A C T of the abdomen demonstrated a large low attenuation mass in the right lobe of the liver, which had marked enhancement (Fig 1) after intravenous contrast infusion. A 72-hour total body gallium scan (Fig 2) demonstrated a large focal area of increased uptake in the area abnormal on the CT. No other abnormalities were noted. Biopsy of the mass demonstrated hepatocellular carcinoma. Gallium-67 citrate, a cyclotron-produced radiopharmaceutical, with a half-life of approximately 3 days, has received widespread use in the evaluation of patients with suspected inflammatory and neoplastic processes. After intravenous injection, gallium is protein bound primarily to the beta globulin transferrin. The precise localization of gallium in both tumors and areas of infection is unclear. It is probably related both to gallium labeling of proteins, plus exudation of gallium-labeled leukocytes. Focal areas of gallium uptake in the liver are frequently noted with pyogenic abscesses and hepatoma. Less common