Assessment of pulmonary arteriovenous malformation with ultra-short echo time magnetic resonance imaging.

PURPOSE: The purpose of this study was to evaluate the diagnostic performance of ultra-short echo time magnetic resonance imaging (UTE MRI) in the assessment of pulmonary arteriovenous malformation (PAVM). METHODS: Eighteen consecutive patients (mean [± standard deviation] age, 48.6 ± 16.8 years) with 46 untreated PAVMs who underwent and thin-section computed tomography (CT) and UTE MRI with a 1.5-Tesla and 3-Tesla unit were retrospectively assessed. Two radiologists evaluated the diagnostic capabilities of UTE MRI for the detection and classification of PAVMs with reference to CT. Sensitivity, specificity, and kappa statistics were calculated with reference to CT. We also compared the differences in PAVM measurements between CT and MRI. RESULTS: The sensitivity and specificity of UTE-MRI for the detection of PAVMs were 89.1% and 100%, respectively, for reader 1 and 87.0% and 100%, respectively, for reader 2. In the classification of PAVMs, inter-modality agreement in reader 1 and 2 were both substantial (κ = 0.78 and 0.69, respectively). The measurements of the PAVM feeding artery and sac on CT and MRI were strongly correlated in both readers 1 and 2 (R2 = 0.981 and 0.983, respectively). Both readers 1 and 2 slightly underestimated the diameter of the PAVM feeding artery and sac on UTE MRI (p < 0.001). CONCLUSION: This study indicates that UTE MRI is a feasible and promising modality for noninvasive assessment of PAVMs.

Diffusion-weighted MR Imaging for the Assessment of Renal Function: Analysis Using Statistical Models Based on Truncated Gaussian and Gamma Distributions.

PURPOSE: To determine the appropriateness of statistical models using the truncated Gaussian distribution and gamma distribution for diffusion signal decay, and to assess the correlation between the parameters obtained from the statistical models and estimated glomerular filtration rate (eGFR). METHODS: Twenty-nine patients with chronic kidney disease and 21 healthy volunteers were included and classified in four groups according to eGFR (ml/min/1.73 m(2)): group 1 (90 ≤ eGFR, n = 10), group 2 (eGFR 60-90, n = 15), group 3 (eGFR 30-60, n = 17), and group 4 (eGFR < 30, n = 8). Diffusion-weighted imaging using five b-values (0, 500, 1000, 1500, and 2000 s/mm(2)) was performed. Truncated Gaussian and gamma models were compared for goodness of fit. Area fractions for the diffusion coefficient D < 1.0 × 10(-3) mm(2)/s (Frac < 1.0) and D > 3.0 × 10(-3) mm(2)/s (Frac > 3.0) obtained from the statistical model were compared among four groups. Correlation between proposed parameters and conventional apparent diffusion coefficient (ADC) with eGFR was calculated. RESULTS: There was no significant difference in goodness of fit between the truncated Gaussian and gamma models. Frac < 1.0 and Frac > 3.0 showed good correlation with eGFR, as did ADC. Comparison between groups 1 and 2 showed that only Frac < 1.0 in both distribution models had significant differences. CONCLUSION: Statistical models yield robust interpretation of diffusion magnetic resonance (MR) signals with relevance to histological changes in the kidney. The parameters of the statistical models, particularly Frac < 1.0, strongly correlated with eGFR.

Semiquantitative assessment of MR imaging in prediction of efficacy of gonadotropin-releasing hormone agonist for volume reduction of uterine leiomyoma: initial experience.

PURPOSE: To prospectively determine if semiquantitative assessment of R2* images and T1-weighted magnetic resonance (MR) images of leiomyomas correlates with the efficacy of gonadotropin-releasing hormone (GnRH) agonist treatment for volume reduction. MATERIALS AND METHODS: Internal review board approval and informed consent were obtained for this study. Twenty women (mean age, 36.3 years) with intramyometrial leiomyomas were enrolled in this study. Single-section double-echo dynamic MR imaging was performed before GnRH agonist administration. T2-weighted images were obtained before and after two or three GnRH agonist injections (1.88 mg leuprorelin acetate). The steepest signal intensity (SI) upslope on T1-weighted images and the area under the curve (AUC) on R2* images were determined by using a 16 x 16-voxel matrix that was placed in the center of a leiomyoma. Pearson correlation analysis was performed to compare the percentage of volume reduction with SI upslope and AUC. Unpaired t test was performed to evaluate the difference between leiomyomas with AUC and SI upslope values that were less than or greater than the mean. RESULTS: Percentage of volume reduction ranged from 6.2% to 51.1%. The mean AUC and mean SI upslope were 39.2 and 9.83% per second, respectively. There was a significant correlation between the AUC and the percentage of volume reduction (r = 0.81, P < .001), although no significant correlation was observed between the SI upslope and the percentage of volume reduction. A significant difference in percentage of volume reduction was observed in leiomyomas by using mean AUC as a cutoff value (P = .003). CONCLUSION: AUC on R2* images correlates with the efficacy of GnRH agonist before initiation of treatment for volume reduction of leiomyoma.

[Chronological change in the national health insurance reimbursement based on the DPC package payment system regarding 131I internal therapy].

The national health reimbursement in 131I internal therapy for thyroid cancer and Graves' disease has increased by introducing the DPC package payment system. The thyroid cancer administration fee for shield room should be increased because of the strict regulation for 131I internal therapy, expensive equipments, confinement of radiopharmaceutical supply, and low efficiency in admission to shield rooms. In addition, the Graves' disease administration fee for shield room should be introduced since the inpatients undergo the same administration and care as the thyroid cancer inpatients.