Utility of combining multiple parameters of 123I-IMP SPECT and voxel-based morphometry MRI using a multiparametric scoring system for differentiating dementia with Lewy bodies from Alzheimer's disease.

BACKGROUND: Brain magnetic resonance imaging voxel-based morphometry (VBM) and perfusion single-photon emission computed tomography (SPECT) are useful for differentiating dementia with Lewy bodies (DLB) from Alzheimer's disease (AD). PURPOSE: To determine whether combining multiple parameters of VBM and SPECT using a multiparametric scoring system (MSS) improves diagnostic accuracy in differentiating DLB from AD. MATERIAL AND METHODS: In total, 23 patients with DLB and 57 patients with AD underwent imaging using a voxel-based specific regional analysis system for AD (VSRAD), an easy Z-score imaging system, and a Z-Graph using three-dimensional stereotactic surface projection. The cutoff values were determined using the receiver operating characteristic curve to differentiate DLB from AD for all parameters. Patients were scored 1 (DLB) or 0 (AD) for each statistically significant parameter, according to a threshold. The total score was determined for each case to obtain a cutoff value for the MSS. RESULTS: The mean Z-scores in the medial temporal lobes using the VSRAD were significantly lower in patients with DLB than in those with AD. Each Z-score of the summed Z-scores in all four segmented regions of the occipital lobes using the Z-Graph was significantly higher in patients with DLB than in those with AD. Among the five parameters, the highest accuracy was 80% for the Z-score of the summed Z-scores in the left medial occipital lobe. For the MSS, a cutoff value of four improved the diagnostic accuracy to 82%. CONCLUSION: MSS was more accurate than any single parameter of VBM or SPECT in differentiating DLB from AD.

High Signal Intensity of the Cochlear Modiolus on Unenhanced T1-Weighted Images in Classical Infratentorial Superficial Siderosis.

Background: Superficial siderosis (SS) results from chronic bleeding in the subarachnoid space. SS can be classified as infratentorial SS (i-SS) and supratentorial SS (s-SS). The cochlear modiolus (CM) normally shows low signal intensity (SI) on Tl-weighted images (T1WI). We noticed persistently high SI of the CM on unenhanced thin-sliced T1WI in patients with i-SS. The purpose of this study was to evaluate the correlation between SS and high SI of the CM on unenhanced T1WI. Methods: This retrospective study analyzed three cases with i-SS, eight cases with s-SS, and 23 normal controls (NC) evaluated on unenhanced thin-sliced T1WI with a three-dimensional spoiled gradient-recalled echo sequence. CM-T1SI scores of 0, 1, and 2 indicated low, iso, and high SI, respectively. In cases with scores of 2 evaluated several times, all scores were reviewed for each case. The CM-T1SI ratio was defined as the contrast ratio between the CM and the cerebellum. Differences between the three groups were statistically analyzed based on the CM-T1SI score and ratio. Receiver operative curve (ROC) analysis was used to determine the cut-off values for differentiating the i-SS group from the NC group based on the CM-T1SI ratio. Results: Two patients with i-SS had a score of 2 on all evaluations. The CM-T1SI score and ratio differed significantly between the i-SS and NC groups. The accuracy of the CM-T1SI ratio for discriminating i-SS from NC was 98.9% at a cutoff value of 0.628. Conclusion: High SI of the CM on unenhanced TIWI can be an additional characteristic finding of i-SS.

NEAT1 Confers Radioresistance to Hepatocellular Carcinoma Cells by Inducing Autophagy through GABARAP.

A long noncoding RNA (lncRNA), nuclear enriched abundant transcript 1 (NEAT1) variant 1 (NEAT1v1), is involved in the maintenance of cancer stem cells (CSCs) in hepatocellular carcinoma (HCC). CSCs are suggested to play important roles in therapeutic resistance. Therefore, we investigated whether NEAT1v1 is involved in the sensitivity to radiation therapy in HCC. Gene knockdown was performed using short hairpin RNAs, and NEAT1v1-overexpressing HCC cell lines were generated by stable transfection with a NEAT1v1-expressing plasmid DNA. Cells were irradiated using an X-ray generator. We found that NEAT1 knockdown enhanced the radiosensitivity of HCC cell lines and concomitantly inhibited autophagy. NEAT1v1 overexpression enhanced autophagy in the irradiated cells and conferred radioresistance. Gamma-aminobutyric acid receptor-associated protein (GABARAP) expression was downregulated by NEAT1 knockdown, whereas it was upregulated in NEAT1v1-overexpressing cells. Moreover, GABARAP was required for NEAT1v1-induced autophagy and radioresistance as its knockdown significantly inhibited autophagy and sensitized the cells to radiation. Since GABARAP is a crucial protein for the autophagosome-lysosome fusion, our results suggest that NEAT1v1 confers radioresistance to HCC by promoting autophagy through GABARAP.

Fluorodeoxyglucose Uptake on Positron Emission Tomography Is a Useful Predictor of Long-Term Pain Control After Palliative Radiation Therapy in Patients With Painful Bone Metastases: Results of a Single-Institute Prospective Study.

PURPOSE: To determine whether fluorodeoxyglucose positron emission tomography (FDG-PET) before and after palliative radiation therapy (RT) can predict long-term pain control in patients with painful bone metastases. METHODS AND MATERIALS: Thirty-one patients with bone metastases who received RT were prospectively included. Forty painful metastatic treatment fields were evaluated. All patients had undergone pre-RT and post-RT PET/CT scanning. We evaluated the relationships between the pre-RT, post-RT, and changes in maximum standardized uptake value (SUVmax) and the pain response, and between SUVmax and pain relapse of the bone metastases in the treatment field. In addition, we compared the SUVmax according to the length of time from the completion of RT to pain relapse of the bone metastases. RESULTS: Regarding the pain response at 4 weeks after the completion of RT, there were 36 lesions of 27 patients in the responder group and 4 lesions of 4 patients in the nonresponder group. Changes in the SUVmax differed significantly between the responder and nonresponder groups in both the early and delayed phases (P=.0292 and P=.0139, respectively), but no relationship was observed between the pre-RT and post-RT SUVmax relative to the pain response. The responder group was evaluated for the rate of relapse. Thirty-five lesions of 26 patients in the responder group were evaluated, because 1 patient died of acute renal failure at 2 months after RT. Twelve lesions (34%) showed pain relapse, and 23 lesions (66%) did not. There were significant differences between the relapse and nonrelapse patients in terms of the pre-RT (early/delayed phases: P<.0001/P<.0001), post-RT (P=.0199/P=.0261), and changes in SUVmax (P=.0004/P=.004). CONCLUSIONS: FDG-PET may help predict the outcome of pain control in the treatment field after palliative RT for painful bone metastases.

Radiation-induced microbleeds after cranial irradiation: evaluation by phase-sensitive magnetic resonance imaging with 3.0 tesla.

BACKGROUND: Although there are many reports regarding radiation-induced microbleeds, its frequency, relation to dose and latency after radiation are not fully elucidated. The purpose of this study was to evaluate the frequency, latency, patient factors and dose relation of radiation-induced microbleeds after cranial irradiation using phase-sensitive magnetic resonance imaging (PSI) at 3.0 T. METHODS: Retrospective evaluation of 34 patients (age range, 13-78 years; mean, 49 years; follow-up period, 3-169 months; mean 29 months) who had undergone cranial irradiation using magnetic resonance (MR) imaging including PSI was performed. Twenty-three patients received high-dose irradiation (44-60 Gy), and 11 patients received 24-30 Gy whole brain irradiation. When microbleeds were detected on MR imaging in these high-dose irradiation patients, dose distribution maps were reproduced by reviewing the clinical records. Then the irradiated areas were divided into 6 radiation-dose classes: regions > 55 Gy, 45-55 Gy, 35-45 Gy, 25-35 Gy, 15-25 Gy and 5-15 Gy. The frequency of microbleeds in each radiation-dose class was analyzed. RESULTS: Microbleeds were detected in 7 (21%) of 34 patients on T2-weighted imaging, whereas they were detected in 16 (47%) of the 34 patients on PSIs. The frequency of microbleeds was higher than previously reported. The latency of radiation-induced microbleeds after radiation was 3 months to 9 years (mean, 33 months). In high-dose irradiation patients, the frequency of microbleeds significantly was associated with radiation dose. There were no foci that were observed in regions that had received < 25 Gy. CONCLUSION: Radiation-induced microbleeds occurred more frequently in the present study than has been previously reported. PSI can be used to detect these vascular changes earlier than other conventional MR imaging techniques.