Impaired Tc-99m MIBI uptake in the thyroid and parathyroid glands during early phase imaging in hemodialysis patients.

The purpose of this study is to evaluate the possible reasons of an observation of diminished uptake of Tc-99m MIBI in the early phase of parathyroid scintigraphy in the thyroid and parathyroid glands in patients with chronic renal failure who are being evaluated for hyperparathyroidism. Fourteen patients with secondary hyperparathyroidism all on hemodialysis with supplement therapy consisting of mainly vitamin D and calcium carbonate were studied. Neck and mediastinum images obtained at early and late phases were evaluated both visually and semiquantitatively. Patients with high PTH levels on hemodialysis showed diminished accumulation of radioactivity in the thyroid glands in the early phase compared to the soft tissue with a ratio of 1.54 +/- 0.39 (mean +/- std). A control group consisting of 10 patients with osteoporosis and Rickets' disease on vitamin D therapy was taken as control group A, as well as 11 patients with no problems other than cardiac who were not on any medication as control group B and 8 patients on hemodialysis only with normal PTH levels as control group C. Patients in control group A and C showed diminished accumulation of radioactivity in the thyroid glands in the early phase compared to the soft tissue with a ratio of 1.57 +/- 0.43 and 1.34 +/- 0.13, respectively, while patients in control group B showed good uptake 3.18 +/- 0.43. None of the studies showed parathyroid pathology. The results of this study show that patients with chronic renal failure under hemodialysis treatment are prone to show decreased uptake of the radioactivity. Another finding is that vitamin D supplements can cause diminished uptake of Tc-99m MIBI. A possible explanation is mentioned in the literature by an increase in PGP level and multi-drug resistance, so we suggest that it may play a role in impaired Tc-99m MIBI uptake in the thyroid phase and recommend cessation of vitamin D3 metabolites before performing parathyroid scintigraphy.

Multiple brown tumors simulating bone metastases: a case of parathyroid adenoma coexisting with papillary carcinoma of the thyroid.

A 55-year-old man with multiple brown tumors who initially was thought to have multiple bone metastases is described. He had elevated parathyroid hormone levels and was referred to the nuclear medicine department, where a parathyroid adenoma was diagnosed. At surgery, abnormal lymph nodes were seen, which were found to contain metastatic thyroid papillary carcinoma cells. On further exploration, the patient's bone scintigraph revealed multiple sites of increased uptake but no bone abnormalities on whole-body iodine and Tc-99m MIBI scans.

Role of technetium tetrofosmin scintimammography in the diagnosis of malignant breast masses and axillary lymph node involvement: a comparative study with mammography and histopathology.

OBJECTIVE: To assess the role of Technetium-99m (99mTc) tetrofosmin scintimammography in the detection of breast cancer and involvement of axillary nodes. DESIGN: Open study. SETTING: General hospital, Turkey. SUBJECTS: 128 women who presented with masses in the breast. INTERVENTIONS: Scintimammography, standard mammography, and either excision or fine-needle aspiration biopsy to confirm the diagnosis. MAIN OUTCOME MEASURES: Sensitivity, specificity, and positive and negative predictive value of scintimammography compared with mammography. RESULTS: Sensitivity, specificity, and positive and negative predictive value (%) of 99mTc scintimammography were 95, 96, 97 and 92, respectively. The corresponding figures for standard mammography were 87, 26, 68 and 52. Scintimammography changed the 34 false positive mammograms into true negatives, at the expense of four false negatives. The sensitivity of scintimammography in detecting axillary lymph node metastases was 72% and specificity 100%. CONCLUSION: Scintimammography with 99mTc tetrofosmin seems to be of value in the detection of breast malignancy and axillary metastases. It may help to avoid unnecessary operations in patients whose mammograms do not give a definite diagnosis.

Asymptomatic or minimally symptomatic traumatic epidural haematomas: comparison of the results of surgical and conservative management related to SPECT and neuropsychological tests. Preliminary results.

One hundred and thirteen patients with asymptomatic or minimally symptomatic epidural heamatomas treated surgically or conservatively in our department were collected prospectively. Between 3 and 6 months after the head injury a SPECT (single photon emission computed tomography) study for evaluation of the three-dimensional cerebral blood flow distribution and extensive neuropsychological tests were performed in 22 patients. The preliminary results of this prospective study have demonstrated that minimally symptomatic or asymptomatic EDHs cause no pathologic SPECT findings and that neuropsychological impairment and duration of the haematoma do not affect the results of conservative management.

Modified Charles operation for primary fibrosclerotic lymphedema.

Radical excision of lymphedematous tissue with skin grafting (Charles operation) may be required for patients with advanced fibrosclerotic lower extremity lymphedema. Complications of this procedure include papillomatosis, wart formation, intractable skin ulcerations and weeping of lymph and are often considered major drawbacks of the operation. We have largely circumvented these sequelae by burying a strip of shaved split-thickness skin graft into the deep subcutaneous tissue thereby modifying the Charles operation. The strip of deepithelialized skin seemingly connects the superficial dermal lymphatics with subfascial deep lymphatics thereby facilitating lymph drainage and minimizing lymphedema accumulation and the complications outlined above. We have now treated 4 patients with advanced primary fibrosclerotic lymphedema using this modified technique. Not only were the patients improved in appearance and function with less trophic changes, but lymphscintigraphy using 99mTc-dextran also suggested improved interstitial tracer transport.

Increased bone marrow uptake on Tc-99m DMSA scintigraphy in a patient with renal osteodystrophy.

A 16-year-old male patient was evaluated with Tc-99m Diethylenetriamine-pentaacetic acid (DTPA) and Tc-99m 2-3 Dimercaptosuccinic acid (DMSA) scintigraphy for renal failure secondary to renal calculi. The uptake in the renal cortex was significantly decreased both on DMSA and DTPA studies. Uptake calculation on DMSA scintigraphy in the kidneys disclosed values of less than 5%. The activity in the liver and bone was significantly increased. A bone scan performed with Tc-99m methylene diphosphonate (MDP) revealed increased bone uptake with decreased soft tissue activity. Findings on bone scan were compatible with super scan, most likely due to renal osteodystrophy. This case illustrates the altered biodistribution of Tc-99m DMSA and a shift of the radiopharmaceutical to the bone marrow which is not likely related to colloid formation due to changes in mineral balance in patients with renal failure.

Evaluation of 99Tcm-labelled alpha-D-glucose 1-phosphate aerosols for SPECT ventilation lung imaging.

The purpose of the present investigation was to evaluate 99Tcm-labelled alpha-D-glucose 1-phosphate (GP) aerosols for single photon emission computed tomographic (SPECT) ventilation lung imaging in comparison to 99Tcm-diethylenetriaminepentaacetate (DTPA) aerosols. Ten normal nonsmoking male volunteers (aged 20-30 years) were included in this study after obtaining their informed consent. 99Tcm-GP, 30 mCi, in 2 ml was placed in the nebulizer (Venticis II) and inhalation continued for 5 min of normal breathing with oxygen flowing through. In 10 subjects dynamic images were obtained from the posterior position for 90 min with 45 frames on a 64 x 64 matrix by the use of a gamma camera. At the end of the dynamic study planar images of the lung (anterior, posterior and laterals) were recorded. Decay corrected clearance curves and kep values were obtained by the pulmonary epithelial programme and T1/2 values were calculated. The same procedure was followed by the use of 99Tcm-DTPA in the same subjects 2 weeks later. SPECT studies of the lung were performed in five subjects after inhalation of 99Tcm-GP aerosols. Clearance curves were monoexponential. The difference in T1/2 values between the right and left lungs was statistically insignificant (P > 0.10). The mean T1/2 values were 316.5 +/- 44.7 and 80.8 +/- 13.4 min for 99Tcm-GP and 99Tcm-DTPA, respectively. The difference was significant (P < 0.0005). On scintigraphic images 99Tcm-GP showed high alveolar deposition and low adhesion to major airways like 99Tcm-DTPA. However, it is preferred to 99Tcm-DTPA for SPECT studies because of its prolonged pulmonary clearance.

Investigation of the effect of magnetic retention systems used in prostheses on buccal mucosal blood flow.

The purpose of this study was to investigate the probable effects of the magnetic field produced by dental magnets on neighboring capillary circulation. Ten subjects were used. Transparent acrylic resin devices were prepared to receive the dental magnets and were used continually by subjects except during sleep. The maxillary buccal mucosal blood flow was measured on both sides (control and experimental) in the same subjects before the use of dental magnets and after 3, 7, 15, 30, and 45 days by the 133Xe clearance technique. Upon analysis it was found that the difference in blood flow between the control and experimental sides was insignificant (P greater than .05). The decrease in blood flow as time progressed was attributed to the pressure exerted by the oral devices rather than by the effect of the magnetic field.

Effect of wearing complete dentures on human palatal mucosal blood flow measured by 133Xe clearance.

In eight edentulous subjects, who had not previously worn dentures, blood flow was measured by 133Xe clearance after intramucosal injection. Upper and lower complete dentures were then constructed for these subjects, and 133Xe clearance was measured after the dentures had been worn for 7 and 40 days. Before the insertion of dentures the mean blood flow to palatal mucosa was 18.9 +/- 7.1 ml/100 g/min. Seven and 40 days after wearing dentures the mean flows to the palatal mucosa were 10.6 +/- 4.5 and 12.6 +/- 5.3 ml/100 g/min, respectively. The difference before and after wearing dentures was statistically significant (p less than 0.05). The subjects were asked not to wear the dentures for 24 h after the third visit on the 40th day whereupon the blood flow reached almost normal levels (16.2 +/- 5.45 ml/100 g/min). The findings show that wearing dentures hinders the blood supply to the palatal mucosa, and that after resting the oral tissues, blood flow may return to normal levels.

Lymphoscintigraphic evaluation of primary congenital lymphedema.

A-four-year-old girl with primary nonfamilial congenital lymphedema was evaluated by lymphoscintigraphy using 99mTc-Dextran. It was demonstrated that there was no accumulation of radioactivity in the left inguinal and femoral lymph nodes and faint accumulation in the contralateral lymph node. It was concluded that lymphoscintigraphy is a safe, reliable, noninvasive technique which is helpful in the evaluation of a patient with lymphedema, especially small children in whom conventional contrast lymphangiography offers some challenges.

Iliopelvic lymphoscintigraphy with 99mTc-dextran in malignant lymphoma.

99mTc-Dextran (99mTc-D) was evaluated as an iliopelvic lymphoscintigraphic agent in 49 patients with malignant lymphoma and the results were compared with ultrasound (US), lymphangiography (LA) and CT where available. Scintigrams were obtained by a gamma camera at 2 h postinjection and evaluated by comparing opposite sides. In 29 of 49 patients, normal lymphoscintigrams of excellent quality, deliniating the iliopelvic and paraaortic lymph nodes bilaterally were obtained. In 20 patients lymphoscintigraphy (LS) was positive. US was performed in 46 patients, 20 had positive and 26 negative findings. There was one false positive and one false negative in LS compared to US. Ten patients had LA and 3 had CT. These results were in complete agreement with LS. There was also a positive correlation between the clinical stages and the results of LS. This study showed that 99mTc-D is an excellent radiopharmaceutical for the visualization of the lymph system with high correlation with other imaging modalities.