Monitoring treatment responses in patients with pulmonary TB using serial lung gallium-67 scintigraphy.

OBJECTIVE: Gallium-67 scintigraphy is more sensitive than chest radiography in a single concurrent detection of pulmonary tuberculosis (TB). As for inflammation, the intensity of pulmonary uptake of 67Ga citrate theoretically is a function of the inflammation level in the lung. To maximize clinical applicability of 67Ga scintigraphy in the evaluation of pulmonary TB, we prospectively assessed serial qualitative associations between intensity of the uptake of 67Ga citrate and the severity of lung inflammation, reflected by the burden of Mycobacterium tuberculosis in the sputum of patients undergoing anti-TB chemotherapy. SUBJECTS AND METHODS: Each enrolled patient had chest radiographic, microbiologic, 67Ga imaging, and semiquantitation of sputum acid-fast bacillus (AFB) assessments before and at the third and sixth months after receiving anti-TB chemotherapy. The burden of pulmonary M. tuberculosis (presumably, in proportion to the semiquantitation of AFB in sputum) and the intensity of 67Ga citrate uptake in the lung at each synchronized assessment were regarded as a paired variable. Odds ratios were obtained from odds (derived using generalized estimating equations) in favor of higher pulmonary 67Ga uptake in differing scores of semiquantitation of sputum AFB. Linear trend for pulmonary 67Ga citrate uptake corresponding to varied pulmonary M. tuberculosis burdens was assessed using contrast analysis of their odds ratios. RESULTS: Thirty patients (24 men and six women) with pulmonary TB were enrolled. Eighty-six paired semiquantitations of sputum AFB-67Ga-scintigraphic studies were collected. Twenty-six patients were cured of their pulmonary TB. The pulmonary 67Ga uptake increased in proportion to the higher score of semiquantitation of sputum AFB (p = 0.009, for trend). CONCLUSION: In patients with pulmonary TB, the higher the burden of M. tuberculosis in the lung, the higher the intensity of pulmonary 67Ga citrate uptake. Serial 67Ga-scintigraphy examinations are helpful in evaluations of the effectiveness of anti-TB therapy when assessments based on chest radiography are difficult.

Influence of 131I diagnostic dose on subsequent ablation in patients with differentiated thyroid carcinoma: discrepancy between the presence of visually apparent stunning and the impairment of successful ablation.

BACKGROUND: In the management of patients with differentiated thyroid carcinoma, direct comparison of the presence of scintigraphic stunning after a diagnostic dose of 131I with subsequent successful ablation has not been evaluated. METHODS: This study included 245 patients who received a dose of 2775-3700 MBq of 131I for thyroid remnant ablation. In all patients, the thyroid-stimulating hormone (TSH) level before ablation was more than 30 microlU x ml. One hundred and twenty-six patients (Group A) were given a 185 MBq diagnostic scan (Dscan) 4-11 days before 131I ablation, and 119 patients (Group B) received 131I ablation directly after thyroidectomy. Scintigraphic stunning was considered to be present on any post-ablation scan that revealed either fewer foci or obviously less prominent uptake compared with the earlier corresponding Dscan. Successful ablation was defined as no visible uptake in the neck region or anywhere else on a follow-up Dscan 6-12 months later. RESULTS: Our results revealed that only 13 of the 126 patients (10.3%) in Group A had visually apparent thyroid stunning. Successful ablation was obtained in 56 of 126 cases (44.4%) in Group A, compared with 86 of 119 cases (72.2%) in Group B (P<0.001). In Group A, the success rate of ablation in patients with stunning (5/13) was not statistically different from that in those without (51/113) (odds ratio, 0.76; 95% CI, 0.23-2.47). Multiple logistic regression analysis revealed that the independent determinants of successful ablation were the use of Dscan before ablation (odds ratio, 0.23; 95% CI, 0.10-0.56) and the ablation dose of 131I (odds ratio, 1.05; 95% CI, 1.00-1.10). CONCLUSIONS: Visually apparent stunning is infrequent and may not be sufficiently sensitive to detect the influence of a 185 MBq Dscan on subsequent ablation outcome. For patients with differentiated thyroid carcinoma, we recommend that ablation should be performed directly after thyroidectomy.