The practical aspects of two recently developed patient dose optimization methods in computed tomography (CT) examinations, size-specific dose estimate (SSDE) and acceptable quality dose (AQD), were verified for the chest and abdomen/pelvis examinations. A dose survey was performed in a CT institute by considering patients lateral diameter, weight and body mass index (BMI). The AQD tables for weight and BMI groups and SSDE threshold curves were obtained. The mean of volume CT dose index and dose length product for standard-size patients were compared with the national diagnostic reference levels (NDRLs) of Iran. The results show that patient doses are below the NDRLs. It is more reliable to report the AQDs based on SSDE and for BMI groups which can well take into account patient size in the dose optimization process. The SSDE threshold curves can be determined with more precision by including dose data of all possible sizes in the curves.

The goal of this study was to evaluate the ability of diffusion-weighted imaging (DWI) with three different b-values compared to apparent diffusion coefficient (ADC) map and fast spin echo heavily T 2 weighted (FSE-HT 2 W) in differential diagnosis of hemangioma from malignant liver lesions. Methods: Fifty-four liver lesions in 20 patients (12 females and eight males: mean age of 52 AE 12.3 years) were examined in this study. FSE-HT 2 W with breath-hold technique and DWI using respiratory triggered with three different b-values (50,400 and 800 s/mm 2) were performed on all patients. Mean ADC values were calculated from each lesion. Agreement levels of each sequence with standard of reference were compared by constructing the receiver operating characteristics (ROC) curve and calculation of the area under the ROC curve. Results: ADC maps had the largest area under the ROC curve and also the most agreement with the standard of reference. DWI obtained with high b-value (b-800 s/mm 2) and FSE-HT 2 W technique were ranked next, respectively. Hemangiomas had significantly higher ADC values than malignant liver lesions (P ¼ .001). No significant differences were seen in gender, age, and lesion size between two lesion groups. Conclusions: ADC maps and DWI in high b-values are more successful than FSE-HT 2 W technique in differential diagnosis of hemangioma from malignant liver lesions.

BackgroundMesenchymal stem cells (MSCs), derived from various tissues, have served as a promising source of cells in clinic and regenerative medicine. Umbilical cord-Wharton's jelly (WJ-MSCs)-derived MSCs exhibit advantages over those from adult tissues, such as no ethical concerns, shorter population doubling time, broad differentiation potential, readily available non-invasive source, prolonged maintenance of stemness properties. Material and methodsThe aim of this study was to evaluate the effect of MRI (1.5 T, 10 min) on stemness gene expression patterns (OCT-4, SOX-2, NANOG) of WJ-MSCs. In addition, we assessed cell viability, growth kinetics and apoptosis of WJ-MSCs after MRI treatment. ResultsThe quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) data showed that transcript levels of SOX-2, NANOG in MRI-treated WJ-MSCs were increased 32-and 213-fold, respectively.MTT assay was performed at 24, 48, and 72 hours post-treatment and the viability was not signi cantly difference between two groups. The doubling time of MRI group was markedly higher than control group.In addition, the colony formation ability of WJ-MSCs after MRI treatment signi cantly increased. Furthermore, no change in apoptosis was seen before or after MRI treatment. ConclusionsOur results suggest the use of MRI can improve quality of MSCs and may enhance the e cacy of mesenchymal stem cell-based therapies.

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