Comparison of two region-of-interest placement methods for histogram analysis of apparent diffusion coefficient maps for glioma grading.

Objectives: We assessed the value of histogram analysis (HA) of apparent diffusion coefficient (ADC) maps for grading low-grade (LGG) and high-grade (HGG) gliomas. Methods: We compared the diagnostic performance of two region-of-interest (ROI) placement methods (ROI 1: the entire tumor; ROI 2: the tumor excluding cystic and necrotic portions). We retrospectively evaluated 54 patients with supratentorial gliomas (18 LGG and 36 HGG). All subjects underwent standard 3T contrast-enhanced magnetic resonance imaging. Histogram parameters of ADC maps calculated with the two segmentation methods comprised mean, median, maxi-mum, minimum, kurtosis, skewness, entropy, standard deviation (sd), mean of positive pixels (mpp), uniformity of positive pixels, and their ratios (r) between lesion and normal white matter. They were compared using the independent t-test, chi-square test, or Mann-Whitney U test. For statistically significant results, receiver operating characteristic curves were constructed, and the optimal cutoff value, sensitivity, and specificity were determined by maximizing Youden's index. Results: The ROI 1 method resulted in significantly higher rADC mean, rADC median, and rADC mpp for LGG than for HGG; these parameters had value for predicting the histological glioma grade with a cutoff (sensitivity, specificity) of 1.88 (77.8%, 61.1%), 2.25 (44.4%, 97.2%), and 1.88 (77.8%, 63.9%), respectively. The ROI 2 method resulted in significantly higher ADC mean, ADC median, ADC mpp, ADC sd, ADC max, rADC median, rADC mpp, rADC mean, rADC sd, and rADC max for LGG than for HGG, while skewness was lower for LGG than for HGG (0.27 [0.98] vs 0.91 [0.81], p = 0.014). In ROI 2, ADC median, ADC mpp, ADC mean, rADC median, rADC mpp, and rADC mean performed well in differentiating glioma grade with cutoffs (sensitivity, specificity) of 1.28 (77.8%, 88.9%), 1.28 (77.8%, 88.9%), 1.25 (77.8%, 91.7%), 1.81 (83.3%, 91.7%), 1.74 (83.3%, 91.7%), and 1.81 (83.3%, 91.7%), respectively. Conclusions: HA parameters had value for grading gliomas. Ex-cluding cystic and necrotic portions of the tumor for measuring HA parameters was preferable to using the entire tumor as the ROI. In this segmentation, rADC median showed the highest performance in predicting histological glioma grade, followed by rADC mpp, rADC mean, ADC median, ADC mpp, and ADC mean.

Evaluation of anatomical factors affecting stress urinary incontinence in female patients via dynamic pelvic floor magnetic resonance imaging.

Objective: To evaluate the anatomical factors affecting stress urinary incontinence (SUI) in female patients via dynamic pelvic floor magnetic resonance imaging (DP-MRI). Methods: This prospective study was conducted on 43 female patients, including 22 patients with SUI (disease group) and 21 patients without SUI (control group). All patients underwent DP-MRI. The length, volume, transverse/anteroposterior diameter, and outer/inner layer thickness of the urethra were measured on static (T2W) pulse sequences. Urethral angle, posterior urethro-vesical angle (PUVA), bladder neck-pubococcygeal angle, and position of the bladder neck and cervix relative to the pubococcygeal line were measured on dynamic (Cine) pulse sequences at rest and during evacuation phase. These parameters were compared between the groups to evaluate which anatomical factors affected SUI. The area under the ROC curve (AUC) and threshold of the sensitivity and specificity of these parameters for the diagnosis of SUI were calculated. Results: The mean age of the patients was 57.3±13.8 years (disease group: 53.9±12.6 years; control group: 60.8±14.4 years). The mean number of childbirths was 2.2±0.65, and vaginal delivery accounted for 73% in each group. There was no significant difference between the two groups in terms of length, transverse diameter, outer layer thickness of the urethra, urethral angle, bladder neck-pubococcygeal angle, position of bladder neck relative to the pubococcygeal line in both resting and evacuation phases (p>0.05). There was a significant difference between the two groups regarding volume (p=0.014), anteroposterior diameter (p=0.01), inner layer thickness of the urethra (p=0.04), and PUVA (p<0.001) at rest and evacuation phases and cervix position at evacuation phase (p=0.001). The AUC of the PUVA for SUI diagnosis was 0.9 at rest and 0.98 during evacuation phases. For the threshold 133.5° at rest phase and 153.5° at evacuation phase, the sensitivity and specificity of PUVA were 0.86 and 0.86 at rest phase and 0.91 and 0.95 at evacuation phase, respectively. Conclusions: PUVA was the anatomical factor that had the greatest effect on SUI and provided high sensitivity and specificity for SUI diag-nosis.