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Biomedical subjects

S Magoun

Publications and source records attributed to S Magoun.

At least 19 recordsLinked to original sources
PubMed1999

Axillary lymph node uptake of Tc-99m MIBI resulting from extravasation should not be misinterpreted as metastasis.

Ipsilateral axillary lymph node visualization due to extravasation of Tc-99m MDP intravenous injection has been well documented. A patient with suspected angina underwent Tc-99m MIBI myocardial SPECT who had extravasation of Tc-99m MIBI in the antecubital region resulting in ipsilateral axillary lymph node uptake. This finding should not be misinterpreted as lymphatic nodal metastasis in a patient with breast cancer or lung cancer.

Angina Pectoris↗
PubMed1999

Detection of abscesses with Tc-99m HMPAO leukocyte scintigraphy depends on their stage and location.

Two abscesses were shown on CT in a 72-year-old man: one in the left hip and one in the left pelvic region that resulted from a motor vehicle collision that occurred 8 months earlier. Bone scintigraphy showed increased uptake in the left hip area. On Tc-99m HMPAO leukocyte imaging, the hip area appeared to be photopenic, and the abscess of the left pelvis was not identified. Incidental uptake in the left lung base appeared to be an active acute inflammatory process as evidenced by an infiltrating lesion in the left lower lung on a chest radiograph. Because leukocyte scintigraphy cannot detect the presence of a chronic inflammatory process in the absence of acute inflammatory cells, the patient's abscesses in the left hip and the left pelvis did not localize Tc-99m HMPAO-labeled neutrophils. The cold lesion in the left hip area was most likely caused by the lesion in the reticuloendothelial system (bone marrow); the unidentifiable pelvic lesion was related to the area(s) outside the reticuloendothelial system. In interpreting a labeled leukocyte image, clinicians should be alert to the stage (chronic or acute) and location (regardless of whether in the reticuloendothelial system) of infectious lesion(s). In this patient, a wide spectrum of manifestations was evident on leukocyte scintigraphy.

Abscess↗
PubMed1999

Normal variants of a photon-deficient area in the lower sternum demonstrated by bone SPECT.

PURPOSE: A highly variable normal appearance of the sternal area makes interpretation difficult on planar bone imaging. These normal variants occur especially in the area above the xiphoid process of the sternum in which an oval photopenic area on anterior planar images may be seen. This finding is most likely caused by localized incomplete fusion. METHODS: Of a group of 188 patients, 35 patients (33 men, 2 women; age range, 30 to 85 years; mean age, 57 years) were examined with sternal SPECT and planar bone imaging. These patients, who had no history of sternal trauma, surgery, radiation, or infection, were referred for bone scan for metastatic work-up (n = 20), back pain (n = 6), and other conditions (n = 9). Thus 11 of 35 (31%) patients had a SPECT study that showed a photopenic area in the lower sternum. RESULTS: The incidence of this normal variant was higher than the 2% to 7.7% previously reported, indicating improved detection by SPECT. The normal variant appears to be less apparent on planar bone images and is seen more clearly on SPECT images. CONCLUSION: Differentiation from malignancy appears to be related to lesion symmetry, location, midline, and evenly distributed radioactivity surrounding the edge of the photopenic area.

Adult↗
PubMed1999

Bone agent localization in hepatic metastases.

We present the bone scintigrams of two patients, which demonstrate diffuse extraosseous uptake of a bone agent in metastatic masses in the liver, one from a primary lung tumor and one from a primary breast tumor. The bone imaging agent did not localize in the brain metastases in these patients. CTs of the abdomen in both patients showed massive metastases in the liver with multiple areas of tumor necrosis. The CT of the abdomen of the breast cancer patient showed multiple small hepatic calcifications. Autopsy revealed massive tumor necrosis with calcifications in the enlarged liver. In routine bone scintigraphy, diffuse uptake of bone agents in the liver of a patient with a known malignancy should be considered suggestive of massive hepatic metastases.

Adenocarcinoma↗
PubMed1999

Localization of a bone imaging agent in a calcified hematoma.

A patient with chronic renal failure and secondary hyperparathyroidism had iliac bone biopsy. The procedure was complicated by a soft-tissue hematoma, which had calcified. A 3-4-cm palpable mass was visible in the lower left abdominal wall. Intense uptake of 99mTc-HMDP corresponded with the location of the calcified hematoma in this patient.

Adult↗
PubMed1998

Functional retention of Tc-99m MIBI in mediastinal lymphomas as a predictor of chemotherapeutic response demonstrated by consecutive thoracic SPECT imaging.

Tc-99m MIBI is used as a tumor imaging agent and has been proposed to measure p-glycoprotein function, which plays an important role in tumor multidrug resistance to chemotherapy. It has been reported that lung cancer and breast cancer with a high retention of Tc-99m MIBI have been more responsive to chemotherapy than tumors with low retention. Thus Tc-99m MIBI SPECT could be used as a measure of p glycoprotein function and consequently may serve as a predictor of the tumor's responsiveness to chemotherapeutic agents. Described here are two patients with lymphomas, one with non-Hodgkin's lymphoma and the other with Hodgkin's disease, who underwent Tc-99m MIBI thoracic SPECT before and after chemotherapy. The sequential studies demonstrated a reduction in tumor size and diminished tumor uptake in one patient and disappearance of tumor uptake after a course of chemotherapy in the other patient. The data suggest that elevated Tc-99m MIBI uptake in a tumor as a result of retention by p glycoprotein not only demonstrates mediastinal involvement of lymphomas but also may be used to forecast responsiveness to chemotherapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Tc-99m MIBI thoracic SPECT for the detection of intrathoracic tumor masses.

Thirty-one men (age range, 46-76 years; mean age, 64.8 years) with intrathoracic masses suggesting possible malignancy on the basis of chest radiography or CT underwent preoperative Tc-99m MIBI SPECT examinations. Diagnosis was confirmed on pathologic examinations of samples obtained either at thoracotomy, esophagectomy, or by biopsy. Twenty-five patients had primary lung cancer, including squamous cell carcinoma, large cell carcinoma, adenocarcinoma, and small cell carcinoma. Two patients had lymphomas with spread to the mediastinum, and three patients had extrathoracic primary cancers (one squamous cell carcinoma of esophagus, one squamous cell carcinoma originating from a head and neck tumor, and one metastatic mediastinal leiomyosarcoma). One patient with a tuberculoma had negative results of the Tc-99m MIBI examination. Tc-99m MIBI had a 86.7% sensitivity rate, a 0% false-positive rate, and a 100% positive predictive value to detect malignant intrathoracic masses. There was a 13% false-negative rate, however, suggesting that MIBI-SPECT may underdiagnose malignant lesions. SPECT findings of these 31 patients can be classified as 1) mass with increased uptake, n = 23; 2) ring-like appearance of increased uptake, n = 3; 3) mass with absent uptake, n = 4; and 4) photon-deficient mass, n = 1. Absent uptake in patients with mass lesions could be explained by necrosis of the lesion (caseation necrosis or massive tumor necrosis with or without bleeding). Most malignant intrathoracic masses are Tc-99m MIBI avid and may be detected with a high degree of sensitivity and with an excellent positive predictive value. A positive MIBI scan may help in the clinical diagnosis of malignancy. The use of Tc-99m MIBI could serve not only as a tumor imaging agent, but also may be used to determine the extent of spread and potentially the chemotherapeutic responsiveness of a tumor.

Aged↗
PubMed1998

An unusual case of a tibial metastasis as the clinical presentation of bronchogenic adenocarcinoma.

A patient with initial complaints of leg pain and difficulty walking was found to have a large right tibial metastatic tumor and poorly differentiated adenocarcinoma of the lung. Findings from total-body bone scintigraphy include a large area of increased uptake in the proximal half of the right tibia with a photon-deficient area medially, and focal areas of uptake in a right rib, in the femoral neck and the left ileum. An irregular area of increased uptake in the left lung mass was shown by thoracic bone SPECT. This is an unusual case of a tibial metastasis as the first clinical presentation of bronchogenic adenocarcinoma.

Adenocarcinoma↗
PubMed1997

A normal technetium-99m-DTPA renogram in renal cell carcinoma: a case report.

A 64-yr-old man with a renal mass had a preoperative 99mTc-DTPA renal flow study and renogram. An area of minimally relative increase in flow in the upper half of the right kidney was thought to reflect the high vascularity of the renal mass. A subsequent renogram showed no mass defect in the area of relatively high flow of the right kidney. The patient had a right nephrectomy. The removed kidney showed an extrarenal mass measuring 6 x 5.5 x 5 cm at the upper pole of the kidney. The mass was confirmed to be a renal cell carcinoma, clear cell type. There was no renal tissue invasion. These finding suggest an extrarenal mass pattern may be difficult to identify with a normal appearing renogram.

Carcinoma, Renal Cell↗
PubMed1996

A mural thrombus of an infrarenal aortic aneurysm demonstrated as photon deficiency in a radionuclide study.

Radionuclide angiogram (RNA) and aortogram may underestimate external aneurysmal diameter. Photon deficient areas are not uncommon along the abdominal aortic aneurysm (AAA) on RNA. To determine whether or not photon deficient areas along the aneurysm could represent a large thrombus, we studied radionuclide aortic angiography in thirty-eight patients during a preoperative cardiac gated study. All the patients (men, ages from 60 to 78) had CT, US, and/or aortogram for comparison. The presence of a thrombus was determined by CT, US, and/or surgical findings. Twelve of 38 (32%) patients' RNA and blood pool images showed photon deficient areas along the aneurysmal walls having a large concentric or eccentric thrombus of the AAA. A large photon deficient area could be detected along the narrowing calibre of the aorta lumen. This finding results from a large mural thrombus being interposed between the left or right bowel/mesentery activity and the activity of the aneurysms functioning patent lumen. We concluded that a photon deficient area along an inferorenal aortic aneurysm may indicate a large thrombus of either eccentric or concentric type within an AAA.

Aged↗
PubMed1996

Medullary thyroid carcinoma imaged by Tc-99m MIBI SPECT and Tl-201 chloride/Tc-99m pertechnetate subtraction SPECT.

A 61-year-old man with medullary thyroid carcinoma and local invasion of the left lobe of the thyroid had Tc-99m MIBI SPECT and Tl-201 chloride/Tc-99m pertechnetate subtraction SPECT after left lobectomy of the thyroid, using a triple-headed gamma camera. Tl-201 chloride/Tc-99m pertechnetate subtraction demonstrated a large mass with high Tl-201 uptake in the left neck. Although there was intense uptake in the tumor in the left thyroid bed on Tc-99m MIBI neck SPECT, there was also uptake in both salivary glands and the right lobe of the thyroid gland. Thus, uptake in the right lobe of the thyroid gland and the salivary glands might not be differentiated from tumor invasion or metastasis from medullary cell carcinoma. Compared with MIBI SPECT, Tl-201 chloride/Tc-99m pertechnetate subtraction SPECT shows more apparent delineation of tumor uptake and may be a preferable technique.

Carcinoma, Medullary↗
PubMed1996

A quadriplegic patient's cholescintigraphic findings: delayed gallbladder visualization and common bile duct dilation.

A Tc-99m DISIDA cholescintigraphic study of a 37-year-old patient with a 20-year history of quadriplegia demonstrated dilation of the common bile duct and delayed gallbladder visualization. A concurrent sonographic study showed an enlarged gallbladder with stones and dilation of the common bile duct. These findings were proved by autopsy. Quadriplegia secondary to a high level of spinal cord injury may result in gallbladder dysfunction.

Adult↗
PubMed1995

Morphine-augmented cholescintigraphy enhances duodenogastric reflux.

Morphine intervention in cholescintigraphy decreases imaging time to diagnose acute cholecystitis. Not infrequently we observe duodenogastric reflux during scintigraphy with and without morphine intervention. To evaluate occurrence of duodenogastric reflux related to morphine, we reviewed 55 patients who underwent cholescintigraphy with (32) and without (23) morphine intervention. Morphine was injected when there was bowel activity with non-visualization of the gallbladder at 60 min. Duodenogastric reflux was identified by the appearance of activity in the area just below or immediately adjacent to the tip of the left hepatic lobe laterally. Among 32 patients with morphine intervention, 19 had acute cholecystitis and 13 chronic cholecystitis. Eleven of 19 (58%) with acute cholecystitis had duodenogastric reflux and 6 of 13 (46%) had duodenogastric reflux in chronic cholecystitis. The total of duodenogastric reflux in the group with morphine injection was 53%. Two patients' duodenogastric reflux occurred before morphine injection and was more apparent after morphine was given. In the without morphine group, 3 had acute cholecystitis and 20 had chronic cholecystitis; 2 (one acute and one chronic cholecystitis) of these 23 (9%) had duodenogastric reflux. Our results indicate: (1) occurrence of DG reflux in morphine augmented cholescintigraphy is not significantly different in cholecystitis from that in chronic cholecystitis; (2) duodenogastric reflux in morphine augmentation occurs significantly more often than without morphine intervention (p < 0.001). We conclude that cholescintigraphy with morphine enhances duodenogastric reflux. The degree of duodenogastric reflux in the acute cholecystitis patients has been more severe than in the chronic cholecystitis patients.

Acute Disease↗