Suvorexant-Induced Dream Enactment Behavior in Parkinson Disease: A Case Report.

ABSTRACT: Suvorexant is a new insomnia drug, and it is generally safe and well tolerated. Here, we report a rare but potentially important adverse effect of suvorexant in a patient with Parkinson disease.

Effect of Reconstruction Strategies for the Quantification and Diagnostic Accuracy of (123)I-FP-CIT SPECT.

PURPOSE: This study evaluates the effect of reconstruction strategies for the quantification and diagnostic accuracy of (123)I-FP-CIT SPECT. METHODS: We evaluated the quantification of (123)I-FP-CIT SPECT obtained by several combinations of reconstruction using the striatal phantom. The phantom images were reconstructed using FBP and OSEM with/without attenuation correction (AC) and scatter correction (SC). We calculated the specific binding ratio (SBR) using volume of interest (VOI) analysis on each reconstructed images. For the clinical study, 40 patients who underwent (123)I-FP-CIT SPECT were selected. We grouped the patients into the normal binding group and decreased binding group according to their clinical diagnosis. The clinical images were reconstructed under the same conditions as the phantom study. The SBRs were calculated, and a receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic accuracy. RESULTS: The SBRs with AC and SC significantly increased compared with no corrections. In the clinical study, although ROC analysis showed no significant difference in the all combinations of reconstruction, the area under the curve using SC and AC tended to be higher than that obtained by other reconstruction. CONCLUSIONS: Quantification of (123)I-FP-CIT SPECT was affected by reconstruction strategies. In addition, both the AC and SC improved the diagnostic accuracy of (123)I-FP-CIT SPECT. Our results suggest that both the AC and SC are recommended for the improving the quantification and diagnostic accuracy in (123)I-FP-CIT SPECT.

Optimization of iterative reconstruction parameters with 3-dimensional resolution recovery, scatter and attenuation correction in ¹²³I-FP-CIT SPECT.

OBJECTIVE: The aim of this study was to determine the optimal reconstruction parameters on ordered-subset expectation maximization iterative reconstruction with resolution recovery, scatter and attenuation correction (OSEM(RRSCAC)) on (123)I-FP-CIT SPECT in terms of the image quality, quantification and diagnostic ability. METHODS: We evaluated the quality and quantification in (123)I-FP-CIT SPECT images obtained by different reconstruction parameters using the anthropomorphic striatal phantom. The phantom images were acquired using a SPECT/CT system equipped with a low- and medium-energy general-purpose collimator and then were reconstructed using OSEM(RRSCAC) with various update numbers and the full width at half maximum (FWHM) of the Gaussian filter. The count ratio of the striatum, the coefficient of variation (CV) on the background and the specific binding ratio (SBR) were calculated to determine the optimal reconstruction parameters. Then, 42 consecutive patients who underwent (123)I-FP-CIT SPECT were selected for clinical study. The patients were grouped into potentially decreasing group (20 with Parkinson's disease, 5 with parkinsonian syndrome and 5 with dementia with Lewy bodies) and potentially normal binding group (4 with Alzheimer disease and 8 with essential tremor). Clinical images were reconstructed using OSEM(RRSCAC) and FBP with Chang's AC (FBP(AC)). The performance of OSEM(RRSCAC) with the optimal reconstruction parameters was evaluated according to the receiver operating characteristic analysis and visual assessment. RESULTS: The count ratio increased with an increasing update number and converged uniformly with an update number over 90. The CV continuously increased with the update number. The SBR also increased with an increasing update number and converged uniformly with an update number of 90 or larger. The FWHM of the Gaussian filter influenced the image quality and quantification. In the clinical study, the area under curve (AUC) for the OSEM(RRSCAC) and FBP(AC) were 0.9812 and 0.9759, respectively. The quality of the SPECT images of OSEM(RRSCAC) (3.8 ± 0.8) was significantly superior to that of FBP(AC) (2.2 ± 0.7). CONCLUSIONS: We determined that the optimal reconstruction parameter for OSEM(RRSCAC) was 90 update numbers with 6.6 mm FWHM of the Gaussian filter. Our results suggested that the optimal reconstruction parameters have a potential to improve the performance and the image quality of (123)I-FP-CIT SPECT in comparison with the FBP reconstruction.