PubMed Health⌕ Search

Biomedical subjects

Leonard M Freeman

Publications and source records attributed to Leonard M Freeman.

13 recordsLinked to original sources
PubMed2005

'Shine through' on dual tracer parathyroid scintigraphy: a potential pitfall in interpretation.

Dual tracer scintigraphy has become the procedure of choice for preoperative localization of parathyroid adenomas. The typical protocol used by most laboratories is to initially perform a Tc-99m sestamibi (MIBI) study with early and delayed (2-3 hours) washout phase images. This is followed by a thyroid-specific Tc-99m pertechnetate study. A potential pitfall exists if the delayed phase of the initial MIBI study shows an intense, abnormal focus of retention. This focus may interfere with interpretation of the subsequent pertechnetate study because of a "shine through" effect. To differentiate a parathyroid adenoma from a thyroid adenoma, it may be necessary to repeat the thyroid-specific pertechnetate scan on a separate day after the dual tracer study.

Adenoma↗
PubMed2005

Lymphangitic spread of breast carcinoma: scintigraphic pattern with chest x-ray and computed tomography correlation.

Lymphangitic spread of metastases has distinct patterns on pulmonary scintigraphy and radiographic imaging. A 43-year-old woman with metastatic breast cancer presented with shortness of breath. Symptomatology was studied with ventilation and perfusion (V/Q) scintigraphy, chest radiograph, and computed tomography (CT). The scintigraphic pattern is consistent with prior descriptions of lymphangitic spread of tumor. The chest x-ray and CT were both performed within the prior 2 months and were confirmatory.

Adult↗
PubMed2004

Samarium-153-Lexidronam complex for treatment of painful bone metastases in hormone-refractory prostate cancer.

OBJECTIVES: A Phase III randomized trial was designed to assess the effectiveness of samarium-153 (153Sm)-lexidronam for palliation of bone pain in patients with hormone-refractory prostate cancer. METHODS: A total of 152 men with hormone-refractory prostate cancer and painful bone metastases were enrolled in a prospective, randomized, double-blind trial comparing radioactive (153Sm) versus nonradioactive (152Sm) lexidronam complexes. Patients were randomized (2:1) to the radioactive (153Sm) agent. Patient diaries recording daily pain and analgesic use were completed during a planned 16-week evaluation period. Nonresponders were informed of the treatment received after 4 weeks of treatment and, if initially treated with placebo, were allowed to receive 153Sm-lexidronam in an open-label fashion. Pain was measured using validated patient-derived visual analog scales and pain descriptor scales. RESULTS: 153Sm-lexidronam had positive effects on measures of pain relief compared with placebo within 1 to 2 weeks. Reductions in opioid use were recorded at weeks 3 and 4. Because nonresponders were unblinded at week 4, statistical comparisons between the arms beyond week 4 were not possible. Mild, transient bone marrow suppression was the only adverse event associated with 153Sm-lexidronam administration. The mean nadir white blood cell and platelet count (3 to 4 weeks after treatment) was 3800/microL and 127,000/microL, respectively. Counts recovered to baseline after approximately 8 weeks. No grade 4 decreases in either platelets or white bloods cells were documented. CONCLUSIONS: These findings demonstrate that 1 mCi/kg 153Sm-lexidronam is both safe and effective for the palliation of painful bone metastases in patients with hormone-refractory prostate cancer.

Aged↗
PubMed2004

Spontaneous retroperitoneal hemorrhage localized by blood pool scintigraphy.

A healthy 17-year-old girl presented to the emergency department with a 1-day history of left upper quadrant abdominal pain associated with nausea and vomiting. Her hematocrit was 22. On physical examination, she had left upper quadrant fullness and tenderness. Initial computed tomography revealed a large, loculated, left-sided retroperitoneal hematoma. Blood pool scintigraphy with labeled red cells revealed a very large photon-deficient area with 3 areas of active bleeding in the upper margin of the cold area. An angiogram showed active extravasation from the left inferior phrenic artery. The patient was felt to have had spontaneous adrenal hemorrhage, likely within a preexisting, large adrenal cyst. Spontaneous hemorrhage into an adrenal cyst is a rare entity that can be life-threatening if not treated early in its course.

Abdominal Pain↗
PubMed2003

Selective role of nuclear medicine in evaluating the acute abdomen.

The imaging evaluation of the acute abdomen has clearly evolved with the introduction of high-resolution imaging techniques, such as CT, US, and MR imaging, leaving scintigraphic examinations an important, though selective, role based on their noninvasive, physiologic, and functional nature. Proper use of these examinations among all the diagnostic methods requires a good understanding of their strengths and limitations.

Abdomen, Acute↗
PubMed2002

Utilization of CT-PA in an emergency department with readily available V/Q scintigraphy.

PURPOSE: To describe the role of computed tomographic pulmonary angiography (CT-PA) in the emergency department of an institution which utilizes ventilation-perfusion (V/Q) scintigraphy as its primary imaging modality for the diagnosis of pulmonary embolism. METHODS AND MATERIALS: We retrospectively identified and reviewed the records of 24 consecutive patients evaluated in the emergency department from October 1998 to September 2000 who were suspected of having pulmonary embolism. The inclusion criterion was that the images from the emergency department and work-up included CT-PA, which was the initial imaging test after chest radiograph. There were 10 men and 14 women with a mean age of 63. Results of CT-PA were categorized as positive, negative, limited negative (no main or lobar pulmonary emboli but not all segmental arteries visualized), or nondiagnostic. Each chart was reviewed with reference to clinical presentation, relevant history, results of Doppler ultrasonography of the legs, V/Q scan and pulmonary angiography, and discharge diagnosis. During the same study period, approximately 400 V/Q scans were performed from the emergency department. RESULTS: Each patient had a clinical presentation consistent with pulmonary embolism. CT-PA diagnosed pulmonary emboli in 21% (5/24), was negative in 33% (8/24), was limited negative in 38% (9/24), and was nondiagnostic in 8% (2/24). Chest radiographs were abnormal in 71% (17/24). V/Q scans were performed in 17% (4/24; 1 near normal, 2 low probability, 1 intermediate probability). None of these four patients was discharged with a diagnosis of pulmonary embolism. Doppler ultrasound leg exam was performed in 38% (9/24). Among the 5 patients diagnosed with pulmonary embolism, 1/3 examined had Doppler evidence of deep vein thrombosis (DVT). Among the 19 patients not diagnosed with pulmonary embolism, 3/6 examined had Doppler evidence of DVT. No patient with a negative or limited negative CT-PA was discharged with a diagnosis of pulmonary embolism. CT-PA provided alternative diagnoses explaining the patient's symptoms in 68% (13/19) of those not diagnosed with pulmonary embolism. During the most recent 12 months of the study period, 210 V/Q scans were performed from the emergency department, with results available in 194 cases as follows: normal/near normal 32% ( n=62), low probability 47% ( n=92), intermediate probability 14% ( n=28), high probability 6% ( n=12). CONCLUSION: V/Q scintigraphy is the primary imaging modality for suspected pulmonary embolism in our emergency department. However, when utilized, CT-PA played an important role in patient management by confirming or excluding pulmonary embolism or providing an alternative diagnosis in the majority of patients suspected of having pulmonary embolism.

Journal Article↗
PubMed2002

The role of positron emission tomography in gastrointestinal imaging.

Although the use of PET in studies of the gastrointestinal tract is still relatively new, its value is clear. The future will provide a better definition of the indications for PET, refinement of the technology, and its relative value compared with other modalities such as peptide and antibody imaging, CT, MR imaging, and US.

Antibodies, Neoplasm↗
PubMed2002

Repeated bleeding scintigraphy may reveal that stationary foci of activity represent sites of active hemorrhage.

The goal of bleeding scintigraphy is to localize the site of origin of a hemorrhage to within general regions of the large or small bowel. Activity is typically seen to extravasate from the blood pool into the lumen, and the collection of activity then moves on sequential images, as a result of the cathartic action of blood. Sometimes, bleeding studies show a stationary focus of activity without subsequent movement. It is generally assumed that these foci represent fixed structures, such as the urinary tract or prominent vasculature, rather than acute extravasation of labeled blood into the bowel. The authors report three cases in which repeated studies showed that fixed foci of activity were, in fact, related to gastrointestinal bleeding. In two instances, the fixed foci represented extravasated blood that, for unexplained reasons, did not move during the study. In an additional case, the fixed activity visualized was ultimately shown to be prominent varices, which were implicated in the bleeding. Recognition of these possibilities, and consideration of possible strategies to localize the bleeding site further, should facilitate optimal patient treatment.

Aged↗
PubMed2002

(99m)Tc sestamibi breast imaging for the examination of patients with dense and fatty breasts: multicenter study.

PURPOSE: To evaluate the accuracy of scintimammography as an adjunct to physical examination and mammography in the detection of breast cancer in women with dense and fatty breasts. MATERIALS AND METHODS: A total of 558 women were prospectively enrolled from 42 centers in North America. Images were interpreted by readers blinded to the subjects' clinical history, mammographic findings, and other test results. The Breast Imaging Reporting and Data System classification was used to describe breast density. Parenchymal patterns of "heterogeneously dense" and "extremely dense" were used to classify breasts as dense, whereas "almost entirely fat" and "numerous vague densities" defined fatty breasts. Between-group differences were evaluated with the 2 test for categorical variables and Student t test for continuous variables. Accuracy of scintimammography was assessed against the core laboratory histopathologic evaluation, the standard. The 95% CIs around point estimates of sensitivity, specificity, and positive and negative predictive values were calculated with the normal approximation to the binomial distribution. RESULTS: The analyses were based on 580 breasts with an abnormality; 276 (48%) breasts were dense and 228 had a malignant lesion. Diagnostic properties for scintimammography of fatty versus dense breasts were, respectively, sensitivity, 72% versus 70%; specificity, 80% versus 78%; positive predictive value, 72% versus 67%; negative predictive value, 81% versus 81%; and accuracy, 77% versus 75% (all not significant). Scintimammography led to similar and significant changes in the posttest likelihood of cancer for both dense and fatty breasts. CONCLUSION: The diagnostic accuracy of scintimammography is not affected by breast density.

Adipose Tissue↗