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One aim of this study is to use non-Gaussian diffusion kurtosis imaging (DKI) for capturing microstructural abnormalities in gray matter of Alzheimer's disease (AD). The other aim is to compare DKI metrics against thickness of cortical gray matter and volume of deep gray matter, respectively. A cohort of 18 patients with AD, 18 patients with amnestic mild cognitive impairment (MCI), and 18 normal controls underwent morphological and DKI MR imaging. Images were investigated using regions-of-interest-based analyses for deep gray matter and vertex-wise analyses for cortical gray matter. In deep gray matter, more regions showed DKI parametric abnormalities than atrophies at the early MCI stage. Mean kurtosis (MK) exhibited the largest number of significant abnormalities among all DKI metrics. At the later AD stage, diffusional abnormalities were observed in fewer regions than atrophies. In cortical gray matter, abnormalities in thickness were mainly in the medial and lateral temporal lobes, which fit the locations of known early pathological changes. Microstructural abnormalities were predominantly in the parietal and even frontal lobes, which fit the locations of known late pathological changes. In conclusion, MK can complement conventional diffusion metrics for detecting microstructural changes, especially in deep gray matter. This study also provides evidence supporting the notion that microstructural changes predate morphological changes. Hum Brain Mapp 38:2495-2508, 2017. © 2017 Wiley Periodicals, Inc.

Objective: To describe the prevalence of synchronous second primary malignancy detected by PET/ CT in our clinical practice and its differentiating features from metastatic lesion. Methods: All PET/CT scans from 1st October 2009 to 30th September 2010 were reviewed. The suspected cases of synchronous second primary malignancy detected by PET/CT were selected, and the histologically confirmed ones were being illustrated. Metachronous second primary cases were excluded. Results: A total of 1522 scans were reviewed. sixty-eight cases were suspected to have a synchronous second primary while 8 were histologically confirmed. Seven (0.4%) of them were malignant and 1 was a benign tumor. These 7 cases were illustrated, and we found a significant difference in SUVmax values and site of occurrence unusual to metastasis that were the two main radiological features differentiating them from metastatic lesion. Conclusion: Synchronous second primary malignancy could be missed without the use of whole body imaging. Its diagnosis is of utmost importance to prevent erroneous upstaging of disease and subsequent palliative treatment instead of curative surgery. [ABSTRACT FROM AUTHOR]

We compared the parameters derived from diffusion-weighted imaging (DWI) and positron emission tomography/computed tomography (PET/CT) for treatment response evaluation and response prediction in patients with gastrointestinal stromal tumor (GIST). Seven patients with histologically proven metastatic disease were enrolled. DWI and PET/CT data were collected from all patients at diagnosis and from six at follow-up. All 37 lesions were identifiable in DWI with a sensitivity of 100%. To achieve higher accuracy, we used the apparent diffusion coefficient (ADC) of liver and background noise as thresholds for the measurement of the ADCs of lesions. Significant inverse correlations were found between ADCmean_thr (ADCmean with thresholds) and SUVmean (mean standardized uptake value) ( R2 = 0.523, p < 0.001 at diagnosis, and R2 = 0.916, p < 0.001 at follow-up), between ADCmean_thr and SUVmax (maximum SUV) ( R2 = 0.529, p < 0.001 at diagnosis, and R2 = 0.761, p < 0.001 at follow-up), between ΔADCmean_thr (percentage change in ADCmean_thr) and ΔSUVmean (percentage change in SUVmean) ( R2 = 0.384, p < 0.001), and between ΔADCmean_thr and ΔSUVmax (percentage change in SUVmax) ( R2 = 0.500, p < 0.001). In lesion-based analysis, pre-treatment ADCmean_thr outperformed SUVmean and SUVmax in treatment response prediction, with an area under the receiver operating characteristic curve of 0.706. These results show that DWI can provide a quantitative assessment comparable with PET/CT in GIST lesion characterization, treatment response evaluation and response prediction. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Objective: There are potential benefits of repetitive transcranial magnetic stimulation (rTMS) in improving swallowing functions after stroke; however, few studies have been performed in the chronic stroke population. This study aims to distil the key effects of rTMS on swallowing functions and swallowing-related quality of life., Methods: Twenty-two participants with chronic post-stroke dysphagia were randomly assigned into active or sham rTMS groups. Seven participants withdrew from the study, thus data from 15 participants (mean age 64.6 years) were analysed. Participants received 3,000 pulses of 5 Hz rTMS (active: n = 11; sham: n = 4) on the tongue area of the motor cortex for 10 days over a period of 2 weeks. All participants were assessed 1 week before, and 2 months, 6 months and 12 months after stimulation. Outcomes were measured by a videofluoroscopic swallowing study, swallowing-related quality-of-life questionnaire and Iowa Oral Performance Instrument., Results: No statistically significant effects were identified for any outcome measures., Conclusion: This study indicates that 5 Hz rTMS applied over the tongue area of the motor cortex is not effective for improving swallowing function in individuals with chronic post-stroke dysphagia. Possible explanations for these non-significant results are dis cussed. Future studies should explore the potential of the current protocol in conjunction with conventional dysphagia therapy.

Objectives: To investigate the usefulness of diffusion weighted imaging (DWI) by comparing with clinical features, blood parameters and traditional short tau inversion recovery (STIR) sequence in detecting spinal and sacroiliac (SI) joint inflammation in axial spondyloarthritis (axSpA) patients., Methods: One hundred and ten axSpA patients were recruited. Clinical, radiological and blood parameters were recorded. DWI and STIR MRI were performed simultaneously and results were scored according to the Spondyloarthritis Research Consortium of Canada (SPARCC) for comparison. Apparent diffusion coef cient (ADC) values were also calculated., Results: DWI did not correlate with clinical parameters or blood parameters. It also had lowered sensitivity. When compared with STIR sequence, it correlated well with STIR sequence at the SI joint level (CC 0.76, p<0.001), but weakly at the spinal level (CC 0.23, p=0.02). At the SI joint level, the presence of inflammation on both STIR sequence and DWI was associated with an increase in maximum (B=0.24, p=0.02 in STIR; B=0.37, p<0.001 in DWI) and mean ADC values (B=0.17, p=0.003 in STIR; B=0.15, p=0.01 in DWI). Maximum (B=0.19, p=0.04) and mean spinal ADC values (B=0.18, p=0.01) were also positively associated with DWI detected spinal inflammation. Presence of Modic lesions showed positive correlation with STIR sequence (B=7.12, p=0.01) but not spinal ADC values., Conclusions: Despite DWI correlates with STIR sequence, it has lower sensitivity. However, ADC values appear to be independent of Modic lesions and may supplement STIR sequence to differentiate degeneration.

Purpose: To assess the knowledge and practice pertaining to radiation exposure related to radiological imaging among medical doctors, in relation to specialty and year of experience., Methodology: Questionnaires as recommended by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) were distributed to doctors in tertiary hospitals by convenience sampling. Their knowledge of radiation doses of common radiological investigations was assessed by any significant difference from correct answers by sampled t-test. Comparison between specialties and between the more (>6 years experience) and less experienced doctors was made by pairwise comparisons of 'right answer minus mean difference (RMD)' using Wilcoxon Signed Ranks Test. Descriptive analysis of their knowledge of harmful effects of radiation and the practices pertaining were also performed., Results: Total 93 questionnaires were sent out and 82 (88.2%, 40 interns, 24 clinicians, 18 radiologists) were returned. Radiologists had the least deviation from correct answers compared to interns (1.29 vs. 2.40, p=0.018) and physicians (1.29 vs. 2.57, p=0.046). More-experienced doctors also performed better than the less-experienced (1.69 vs. 2.57, p=0.027). 12/80 (15%) and 4/80 (5%) failed to recognize MR and US as radiation-free modalities. Only 10/80 (12.5%) knew the risk of carcinogenesis from abdominal CT and only 4/81 (5%) will discuss radiation-related hazard with patients routinely., Conclusion: Knowledge of medical doctors, including radiologists, towards radiation exposure of imaging is unsatisfactory and could imply a tendency of radiation misuse and under-utilization of alternative radiation-free methods. On-job training and discussion of the radiation risk with patients are advised., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Purpose: We investigated the incidence of lymph node metastasis in gastrointestinal stromal tumor (GIST) patients in our PET/CT database. The demographic data and characteristics of the primary tumor were evaluated in GIST patients with or without lymph node metastasis., Materials and Methods: We reviewed our PET/CT database from January 1, 2007 to November 30, 2010 by using keyword search, and identified GIST with lymph node metastasis according to our standard of reference. Statistical analysis was conducted between GIST group with or without lymph node metastasis based on the age, sex, primary tumor size, and primary tumor location., Results: A total of 29 GIST patients were found in our database. Six of them had lymph node metastasis, corresponding to 20.7%. When considering only the adult patients, the incidence was 17% (5 out of 28). There were 4 males and 1 female, with the mean age of 66.8 years old, which was 8 years older than the group without lymph node metastasis. Of the 5 adult metastasis patients, 4 had their primary tumor located at very rare sites other than stomach or small bowel. Statistical analysis using Fisher exact test of rare location showed significance between the 2 groups with P = 0.004. The mean size of the primary tumor in the group with lymph node metastasis was 5.2 cm, which was 2.9 cm less than the group without metastasis. No statistical significance was found in age, sex, or size of primary tumor between the 2 groups., Conclusion: The incidence of lymph node metastasis in GISTs in our database is 20.7%, which is surprisingly higher than we thought from other previous studies. In contrast to the group without lymph node metastasis, these patients tend to be of older ages and had rare location of the primary tumor. This result supports further study with larger sample size.