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Biomedical subjects

A T Isitman

Publications and source records attributed to A T Isitman.

At least 37 records · Page 2Linked to original sources
PubMed1992

Iodine-131 contamination from thyroid cancer patients.

High-dose radioactive iodine therapy using 131I is the treatment of choice for patients with thyroid cancer following thyroidectomy. Because of the large amount of activity which is excreted during hospitalization, contamination hazard from 131I excretion via perspiration, saliva, breath and urine may arise. In eight patients treated with doses of 131I ranging from 3.7 to 14.8 GBq (100-400 mCi), activity levels were measured in room air, from room surfaces, the toilet, the patients' exhaled breath, skin, saliva and toothbrushes, and the gloves used by medical staff. Thyroid bioassays were also performed on medical staff personnel caring for these patients both before and two days after administration of the treatment dose. Removable activity from the skin was positively correlated with treatment dose and reached a maximum at 24 hr post-therapy. Removable activity from room surfaces exceeded the level of contamination which requires clean-up in a restricted area during the patient's hospitalization. Thyroid bioassays on medical staff showed no significant uptake 2 days after treatment. The relatively high activities present in the saliva, urine and on the skin of these patients emphasizes the need for all individuals coming in contact with these patients to be made aware of the contamination hazard present.

Adolescent↗
PubMed1991

Concentration of Tc-99m MDP in ovarian carcinoma and its soft tissue metastases.

A patient with ovarian carcinoma was evaluated for skeletal metastasis with a routine whole body bone scan. Although no bone metastases were visualized, there was dramatic accumulation of tracer in the soft tissues of the abdomen. CT revealed calcifying soft tissue metastases on the liver surface, the bowel serosa, and in the pelvis corresponding to the abnormal areas of Tc-99m MDP uptake. Tumor necrosis and ongoing calcification within the metastatic sites are possible explanations for this unusual soft tissue concentration of the bone-seeking radiopharmaceutical. In patients with metastatic ovarian carcinoma, careful review of extraosseous regions on bone scan images may provide valuable diagnostic information.

Abdominal Neoplasms↗
PubMed1991

Right aortic arch: demonstration by first-pass and multigated radionuclide ventriculography.

Right aortic arch is a rare congenital anomaly associated with abnormal development of the paired embryological aortic arches. While various abnormalities of the great vessels have been described using both first-pass and multigated radionuclide ventriculographic studies, diagnosis of a right-sided aortic arch has typically required a radiographic contrast technique. We present a case of a patient with a suspected right-sided aortic arch diagnosed by radionuclide methods.

Adult↗
PubMed1991

Isolated muscular sarcoidosis causing fever of unknown origin: the value of gallium-67 imaging.

An unusual case of a patient with a long-standing fever of unknown origin (FUO) is presented whose gallium-67 (67Ga) images revealed increased activity only in the calf muscles bilaterally. Other imaging modalities also failed to show chest or other abnormal findings. Subsequent biopsy of the right gastrocnemius muscle revealed noncaseating granulomas consistent with the diagnosis of sarcoidosis. When using 67Ga to evaluate a patient with a FUO, imaging of the extremities should always be included. Also, when abnormal Ga-67 uptake is present in the extremities, sarcoidosis should be included in the differential diagnosis.

Adult↗
PubMed1990

The value of oblique angle reorientation in SPECT bone scintigraphy of the hips.

SPECT bone scintigraphy has been shown useful for detecting avascular necrosis (AVN) of the femoral heads. Because the femoral necks project in a 15-20 degree posterior angulation from the coronal plane, the femoral head is partially superimposed upon the acetabulum in standard coronal SPECT images. To avoid this problem, the authors now perform oblique angle reorientation of all hip SPECT studies. This new technique, which allows display of the hip in a more anatomic fashion and better definition of hip abnormalities, is described. No new data acquisition is needed, and only a small amount of extra time is required for reconstruction.

Adult↗
PubMed1990

The radioactive handkerchief sign. A contamination artifact in I-131 imaging for metastatic thyroid carcinoma.

False-positive findings suggestive of metastatic functioning thyroid carcinoma have been well documented in I-131 whole-body imaging. These artifacts are often associated with contamination from radioiodine-containing body secretions. Recently, a contaminated handkerchief on an iodine-131 whole-body scan was reported. In the following study, two additional cases involving the sequestration of I-131 contaminated handkerchiefs in patients' pockets are presented, and the literature regarding these false-positive findings is reviewed. Although rare, this "radioactive handkerchief sign" may cause serious misinterpretation of a focal radioiodine accumulation.

Adult↗
PubMed1990

Pulmonary embolism as an indicator of occult malignancy.

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.

Gastroscopy↗
PubMed1990

Idiopathic pulmonary fibrosis. A rare cause of scintigraphic ventilation-perfusion mismatch.

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.

Diagnosis, Differential↗
PubMed1989

False-negative radionuclide cisternography in massive communicating hydrocephalus: value of the vertex view and CT correlation.

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.

Adult↗
PubMed1989

Alzheimer disease: quantitative analysis of I-123-iodoamphetamine SPECT brain 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.

Adult↗
PubMed1989

Prospective comparison of radionuclide, computed tomographic, sonographic, and magnetic resonance localization of parathyroid tumors.

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.

Adult↗
PubMed1989

The use of radionuclide cisternography in the diagnosis of pleural cerebrospinal fluid fistulae.

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.

Adolescent↗