Biomedical subjects
Publications and source records attributed to B D Collier.
A case that demonstrates the relationship between malignancy and pulmonary throboembolic disease is presented. Pulmonary embolism, which was diagnosed on a ventilation-perfusion lung scan, initiated a search for the etiology of this condition. Normal examination of the deep venous system of the legs prompted further investigation, which ultimately led to the endoscopic diagnosis of poorly differentiated gastric carcinoma.
Hemangiomas are congenital vascular tumors frequently referred for Tc-99m RBC imaging. A case of soft tissue cavernous hemangioma located in the right side of the face and neck is presented. The importance of the Valsalva maneuver in outlining this lesion is described, and a brief review of the literature is presented.
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A case of idiopathic pulmonary fibrosis with multiple areas of mismatch on ventilation-perfusion lung imaging in the absence of pulmonary embolism is presented. Idiopathic pulmonary fibrosis is one of the few nonembolic diseases producing a pulmonary ventilation-perfusion mismatch. In this condition, chest radiographs may not detect the full extent of disease, and xenon-133 ventilation imaging may be relatively insensitive to morbid changes in small airways. Thus, when examining patients with idiopathic pulmonary fibrosis, one should be aware that abnormal perfusion imaging patterns without matching ventilation abnormalities are not always due to embolism. In this setting, contrast pulmonary angiography is often needed for accurate differential diagnosis.
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In dichotic listening tasks, the (dominant) right ear's superiority in processing verbal stimuli has been attributed to its direct anatomic connection with the left dominant hemisphere. The role played by extralinguistic factors, such as attention and functional tuning of the associated cortical structures, has not been carefully examined. This investigation was undertaken to evaluate the effects of the left thalamic electric stimulation on the processing (recognition and recall) of dichotically presented CVC verbal stimuli in a patient being treated for chronic pain. We report the positive effects of electric stimulation (confirmed by increased subcortical metabolic activity using SPECT, a brain imaging technique) on the processing of dichotically presented verbal stimuli.
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Radionuclide cisternography evaluates cerebrospinal fluid dynamics, while CT and magnetic resonance imaging provide better information about central nervous system anatomy. This article describes two cases of patients with hydrocephalus. Their radionuclide cysternography studies were initially felt to be normal. After correlation with CT scans, massively enlarged ventricles were discovered. Tracer activity had refluxed into the ventricles, simulating normal cerebrospinal fluid rise over the convexities. When radionuclide cisternography studies in patients with excessively enlarged ventricles are interpreted, correlation with other anatomic imaging studies, such as CT and magnetic resonance imaging, is essential. A vertex view acquired during cisternography may also be helpful in correlation with transaxial plane images obtained by CT and magnetic resonance imaging.
To enable a more quantitative diagnosis of senile dementia of the Alzheimer type (SDAT), the authors developed and tested a semiautomated method to define regions of interest (ROIs) to be used in quantitating results from single photon emission computed tomography (SPECT) of regional cerebral blood flow performed with N-isopropyl iodine-123-iodoamphetamine. SPECT/IMP imaging was performed in ten patients with probable SDAT and seven healthy subjects. Multiple ROIs were manually and semiautomatically generated, and uptake was quantitated for each ROI. Mean cortical activity was estimated as the average of the mean activity in 24 semiautomatically generated ROIs; mean cerebellar activity was determined from the mean activity in separate ROIs. A ratio of parietal to cerebellar activity less than 0.60 and a ratio of parietal to mean cortical activity less than 0.90 allowed correct categorization of nine of ten and eight of ten patients, respectively, with SDAT and all control subjects. The degree of diminished mental status observed in patients with SDAT correlated with both global and regional changes in IMP uptake.
The appropriate choice of imaging techniques to localize parathyroid tumors preoperatively remains controversial. We report the first prospective, blinded study to compare the efficacy of four imaging modalities in 100 patients with primary hyperparathyroidism (pHPT). Patients were examined by computer-assisted thallium 201/technetium 99m subtraction scintigraphy (TTS), computed tomography (CT), ultrasonography (US), and magnetic resonance (MR). Each study was performed and interpreted independently. Subsequent neck exploration and "curative" parathyroidectomy allowed correlation of surgical findings with imaging reports to score their accuracy. Overall sensitivities of the four imaging modalities were TTS, 73%, CT, 68%, US, 55%; and MR, 57%; with respective specificities of 94%, 92%, 95%, and 87%. Sensitivities for lesions located below the thyroid gland (thymic tongue and mediastinum) were TTS, 90%; CT, 46%; US, 44%; and MR, 50%; with respective specificities of 100%, 99%, 100%, and 94%. There was a significant increase in overall sensitivity when TTS and CT (90%, p less than 0.01) or TTS and US (85%, p less than 0.05) were used together; however, the combination of any three or even four imaging modalities did not increase sensitivity further. For small parathyroid tumors (less than or equal to 250 mg), no imaging technique had a sensitivity of more than 50%. None of the imaging studies accurately localized small hyperplastic parathyroid glands found in patients with multiple gland disease. Preoperative parathyroid imaging may not be indicated in pHPT patients undergoing first-time neck exploration because surgeons experienced in parathyroid surgery have a 93% to 96% cure rate.
Radionuclide cisternography (RNC) is an excellent method of studying cerebrospinal fluid (CSF) dynamics and fistulous communications. Two patients are described in which pleural cerebrospinal fluid fistulae were found by this technique. In addition, marking the area presurgically reduced operating room time in one patient. Such communications are important to locate since they can cause significant loss of CSF as well as provide a pathway for pathogens to enter the central nervous system.
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In this study we evaluated by blinded design the diagnostic efficacy of two noninvasive techniques, quantitative hepatobiliary scintigraphy (QHS) and fatty-meal sonography (FMS), for evaluating patients with suspected partial common duct obstruction. Quantitative hepatobiliary scintigraphy was performed on 56 cholecystectomized individuals (22 asymptomatic controls, 28 patients with suspected partial common duct obstruction, and 6 nonjaundiced cirrhotics) and FMS was done in 51 cases. For QHS, time-activity curves were generated for regions of interest over the liver, hepatic hilum, and common duct. For FMS, we measured common duct diameter before and 45 min after a fatty meal (Lipomul, 1.5 ml/kg). Each of the 28 patients with suspected partial common duct obstruction and 6 cirrhotic patients underwent endoscopic retrograde cholangiography, often accompanied by sphincter of Oddi manometry. Findings from these examinations were taken as the gold standard to determine the presence or absence of conditions that could account for intermittent symptomatic partial common duct obstruction. The most sensitive indicators for a positive test were a 45-min isotope clearance of less than 63% for QHS and a common duct increase of greater than or equal to 2 mm after the fatty meal for FMS. Of 28 patients with suspected partial common duct obstruction, 15 were judged to be true-positive and 13 true-negative. The 6 cirrhotic patients were without common duct obstruction. The study findings showed that each test had a 67% sensitivity that improved to 80% when the findings from both test results were combined. The specificity of QHS was 85% and that of FMS was 100%. All 6 cirrhotic patients had negative findings on FMS and 4 were false-positive on QHS. The true-positives included 8 patients with a small common duct stone and 6 with obstructive sphincter of Oddi dysfunction (4 stenosis, 2 dyskinesia). We conclude that noninvasive QHS and FMS afford good sensitivity and specificity for evaluating cholecystectomized patients with suspected partial common duct obstruction.
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A case of giant cell tumor of bone is reported in which the blood flow study along with SPECT imaging improved the visualization and diagnosis of the abnormality.
One hundred adult sports medicine patients with clinical findings suggesting chondromalacia of the patella underwent bone imaging. Of these patients, 50 eventually underwent arthroscopic surgery and the remaining 50 were treated conservatively. The intensity of abnormally increased scintigraphic activity in the patella correlated closely with the grade of chondromalacia observed by the arthroscopist. Bone imaging also was of value in directing the arthroscopist to clinically unsuspected torn menisci. In conclusion, for sports medicine patients with clinical findings suggestive of chondromalacia of the patella, bone imaging contributes to an accurate diagnosis and appropriate surgical planning.
A 77-year-old man with prostate cancer was serially evaluated for bone metastases using Tc-99m methylene disphosphonate (Tc-99m MDP) both on and off treatment with etidronate disodium (EHDP). While the patient was receiving the medication only minimal bony uptake of the tracer was seen with the majority remaining in the soft tissues. The similarly structured EHDP probably saturated the binding sites that the radioactive MDP usually adheres to. Physicians should be aware of this interaction and may have to wait until the EHDP has been discontinued for several months before performing bone imaging on these patients.