Changes of cortical activation in swallowing following high frequency repetitive transcranial magnetic stimulation in older adults.

BACKGROUND: This study explored whether high-frequency repetitive transcranial magnetic stimulation (rTMS) can induce positive changes in the cortical areas of older adults who do not have functional difficulties in swallowing. METHODS: Ten healthy, right-handed, elderly volunteers were subjected to 18F-labeled fluorodeoxyglucose positron emission tomography(FDG-PET) scans when at rest, swallowing before rTMS, and swallowing after rTMS. During the swallowing study, water was infused orally via a catheter at a rate of 600 mL/h. Subjects swallowed water every 20 seconds following a light flash for 30 minutes. During rest, the light source was active, but subjects were requested not to swallow. The rTMS consisted of 5 Hz applied to a pharyngeal motor hot spot in the right hemisphere for 10 minutes every weekday for 2 weeks. The intensity of the stimulation was set at 90% of the thenar motor threshold of the same hemisphere. The differences between each patient's active image and the control images (P<.05) on a voxel-by-voxel basis were examined to find significant increases in metabolism using statistical parametric mapping software. KEY RESULTS: The cortical areas activated by swallowing before rTMS included the bilateral sensorimotor cortex (Brodmann's areas 3 and 4) and showed symmetry. The cortical areas activated by swallowing after rTMS were the same as the areas before rTMS. There was no statistical difference between the two swallowing activation areas. CONCLUSIONS AND INFERENCES: Older adults displayed the symmetry of cortical control of swallowing function. High frequency rTMS did not affect the activation in the swallowing sensorimotor cortices of elderly people.

Efficacy of PET/CT in the accurate evaluation of primary colorectal carcinoma.

AIM: This study was performed to assess in the accurate evaluation of primary colorectal carcinoma using PET/CT. METHODS: One hundred patients with primary colorectal carcinoma were evaluated during 2004. All patients underwent PET/CT when their preoperative serum carcinoembryonic antigen was >or=10 ng/mL or when CT showed equivocal findings. The appropriateness of PET/CT-induced changes was noted by subsequent operative findings and follow-up. RESULTS: PET/CT more detected 15 intra-abdominal metastatic lesions than abdomino-pelvic CT scan. PET/CT showed true negative findings in 13 patients and false positive or negative findings in 10. Due to PET/CT results, management plans were altered in 27 patients; 9 had inter-modality changes, 10 received more extensive surgery, and 8 avoided unnecessary procedures. CONCLUSIONS: PET/CT altered management plan in 24% of patients with primary colorectal carcinoma in correct direction. These findings suggest that PET/CT should be considered a part of standard work up for preoperative evaluation in a subset of patients with colorectal carcinoma.

F-18-fluorodeoxyglucose positron emission tomography as a presurgical evaluation modality for I-131 scan-negative thyroid carcinoma patients with local recurrence in cervical lymph nodes.

BACKGROUND: F-18-labeled fluorodeoxyglucose-positron emission tomography (FDG-PET) has a supplementary role in localizing recurrent sites of differentiated thyroid carcinoma. We evaluated whether FDG-PET is feasible as a presurgical evaluation modality for I-131 scan-negative thyroid carcinoma patients. METHODS: Preoperative FDG-PET results were compared with the pathologic findings of lymph nodes specimens of 22 papillary thyroid patients. All patients had thyroidectomy and I-131 ablation therapy beforehand and showed negative I-131 scans on follow-up studies. RESULTS: In 85 cervical lymph node groups dissected, 56 lymph node groups revealed metastasis. The sensitivity and specificity of FDG PET for metastasis were 80% (45 of 56) and 83% (24 of 29), respectively. Among the pathologically positive 33 lymph nodes with normal size(< or =1 cm), FDG-PET detected 23 nodes. Serum thyroglobulin levels were elevated in 12 patients (sensitivity, 55%). CONCLUSION: FDG-PET accurately detected the recurred cervical lymph nodes of differentiated thyroid carcinoma patients who showed negative I-131 scan. FDG-PET is suitable for the presurgical evaluation of these patients.

Pulmonary tuberculoma evaluated by means of FDG PET: findings in 10 cases.

PURPOSE: To describe findings of pulmonary tuberculoma at 2-[fluorine 18]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET). MATERIALS AND METHODS: Ten consecutive patients who underwent PET and subsequently were proved to have pulmonary tuberculoma were analyzed. Tuberculosis was proved histopathologically in eight by means of wedge resection or lobectomy (n = 7) or needle biopsy (n = 1) and in two by means of clinical follow-up for more than 2 years. PET scans were evaluated by using peak standardized uptake values. Computed tomographic (CT) and histopathologic findings also were reviewed. RESULTS: Nine of 10 tuberculomas showed FDG uptake at PET, and the mean peak standardized uptake value was 4.2 +/- 2.2 (SD). FDG uptake (range, 1. 9-3.7) in lesions adjacent to main abnormalities was demonstrated in four patients. On CT scans, the mean of the longest nodule diameters was 21 mm +/- 8, and there were some areas of branching linear opacities or satellite nodules that suggested pulmonary tuberculosis in seven patients. Histopathologic findings were chronic granulomatous inflammation with caseation necrosis (n = 7) and healed tuberculosis with aspergilloma (n = 1). CONCLUSION: Pulmonary tuberculoma commonly causes an increase in FDG uptake. These results suggest that in geographic regions with a high prevalence of granulomatous lesions, positive FDG PET results should be interpreted with caution in differentiating benign from malignant pulmonary abnormalities.

Dosimetry of rhenium-188 diethylene triamine penta-acetic acid for endovascular intra-balloon brachytherapy after coronary angioplasty.

To examine the possibility of using rhenium-188 diethylene triamine penta-acetic acid (DTPA) for endovascular intra-balloon brachytherapy after angioplasty, dose distribution around the balloon was calculated and validated by film dosimetry. Medical internal radiation dosimetry (MIRD) was calculated assuming that the balloon had ruptured and that the contents had been released into the systemic circulation. 188Re-perrhenate eluate from the 188W/188Re generator was concentrated using an ion column and used to label DTPA. The dose distribution around the angioplasty balloon (20 mm length, 3 mm diameter cylinder) was estimated by Monte Carlo simulation using the EGS4 code. The time required for 17.6 Gy to be absorbed at 1 mm from the balloon's surface following application of 3700 MBq/ml of 188Re was found to be 278 s. Fifty percent of the energy was deposited in the first millimetre of the vessel wall from the balloon's surface. The calculated radiation absorbed dose agreed with that measured by film dosimetry, which was performed using a water phantom, with errors ranging from 9.4% to 17%. Upon balloon rupture the total amount of 188Re-DTPA was presumed to enter the systemic circulation. The resulting radiation absorbed dose was calculated using the MIRDOSE3 program and residence times obtained from dogs and amounted to 0.0056 mGy/MBq to the whole body and 4.56 mGy/MBq to the urinary bladder. The absorbed dose of 188Re-DTPA to the whole body was one-tenth of that of 188Re-perrhenate. A window-based program was developed to calculate the exposure time and the radiation dose absorbed as a function of the 188Re concentration and the arbitrary distance from the balloon to the surrounding tissues. We conclude that 188Re-DTPA is easy to prepare, safe to use and suitable for intra-balloon brachytherapy after coronary angioplasty.