BACKGROUND AND PURPOSE: The prediction of treatment response is important in planning and modifying the chemoradiation therapy regimen. This study aimed to explore the quantitative histogram indices for treatment-response prediction of nasopharyngeal carcinoma based on diffusional kurtosis imaging compared with a standard ADC value (ADC standard). MATERIALS AND METHODS: Thirty-six patients with an initial diagnosis of locoregionally advanced nasopharyngeal carcinoma and diffusional kurtosis imaging acquisitions before and after neoadjuvant chemotherapy were enrolled. Patients were divided into respondversus-nonrespond groups after neoadjuvant chemotherapy and residual-versus-nonresidual groups after radiation therapy. Histogram parameters of diffusional kurtosis imaging-derived parameters (ADC, ADC coefficient corrected by the non-Gaussain model [D], apparent kurtosis coefficient without a unit [K]) were calculated. The ADC standard was calculated on the basis of intravoxel incoherent movement data. The intraclass correlation coefficient, Kolmogorov-Smirnov test, Student t test or Mann-Whitney U test, and receiver operating characteristic analysis were performed. RESULTS: Most of the parameters had good-to-excellent consistency (intraclass correlation coefficient ϭ 0.675-0.998). The pre-ADC standard , pre-ADC (10th, 25th, 50th percentiles), pre-D (10th, 25th, 50th percentiles), and pre-K 50th were significantly different between the respond and nonrespond groups, while the pre-ADC 10th , pre-K 90th , post-ADC 50th , post-K 75th , post-K 90th , and the percentage change of parameters before and after neoadjuvant chemotherapy (‚ADC 50th %) were significantly different between the residual and nonresidual groups (all P Ͻ .05). Receiver operating characteristic analysis indicated that setting pre-D 50th ϭ 0.875 ϫ 10 Ϫ3 mm 2 /s as the cutoff value could result in optimal diagnostic performance for neoadjuvant chemotherapy response prediction (area under the curve ϭ 0.814, sensitivity ϭ 0.70, specificity ϭ 0.92), while the post-K 90th ϭ 1.035 (area under the curve ϭ 0.829, sensitivity ϭ 0.78, specificity ϭ 0.72), and‚ADC 50th % ϭ 0.253 (area under the curve ϭ 0.833, sensitivity ϭ 0.94, specificity ϭ 0.72) were optimal for radiation therapy response prediction. CONCLUSIONS: Histogram analysis of diffusional kurtosis imaging may potentially predict the neoadjuvant chemotherapy and shortterm radiation therapy response in locoregionally advanced nasopharyngeal carcinoma, therefore providing evidence for modification of the treatment regimen. ABBREVIATIONS: CR ϭ complete response; D ϭ ADC coefficient corrected by the non-Gaussain model; DKI ϭ diffusional kurtosis imaging; IMRT ϭ intensitymodulated radiation therapy; K ϭ apparent kurtosis coefficient without a unit; NAC ϭ neoadjuvant chemotherapy; NPC ϭ nasopharyngeal carcinoma; PR ϭ partial response; SD ϭ stable disease; ‚ADC 50th % ϭ the percentage change of parameters before and after neoadjuvant chemotherapy N asopharyngeal carcinoma (NPC) is a territorial epidemic in so...

Background Accurate evaluation of the invasion depth of tumors with a Vesical Imaging‐Reporting and Data System (VI‐RADS) score of 3 is difficult. Purpose To evaluate the diagnostic performance of a new magnetic resonance imaging (MRI) strategy based on the integration of the VI‐RADS and tumor contact length (TCL) for the diagnosis of muscle‐invasive bladder cancer (MIBC). Study type Single center, retrospective. Subjects A group of 179 patients with a mean age of 67 years (range, 24.0–96.0) underwent multiparametric MRI (mpMRI) before surgery, including 147 (82.1%) males and 32 (17.9%) females. Twenty‐four (13.4%), 90 (50.3%), 43 (24.0%), 15 (8.4%), and 7 (3.9%) cases were Ta, T1, T2, T3, and T4, respectively. Field Strength/Sequence A 1.5 T and 3.0 T, T2‐weighted turbo spin‐echo (TSE), single‐shot echo‐planar (SS‐EPI), diffusion‐weighted imaging (DWI), and T1‐weighted volumetric interpolated breath‐hold examination (T1‐VIBE). Assessment Three radiologists independently graded the VI‐RADS score and measured the TCL on index lesion images. A proposed MRI strategy called VI‐RADS_TCL was introduced by modifying the VI‐RADS score, which was downgraded to VI‐RADS 3F (equal to a VI‐RADS score of 2) if VI‐RADS = 3 and TCL < 3 cm. Statistical Tests Intraclass correlation coefficients (ICCs), Mann–Whitney U test, chi‐square tests, receiver operating characteristic (ROC) curves, and 2 × 2 contingency tables were applied. Results Inter‐reader agreement values were 0.941 (95% CI, 0.924–0.955) and 0.934 (95% CI, 0.916–0.948) for the TCL and VI‐RADS score. The TCL was significantly increased in the MIBC group (6.40–6.85 cm) compared with the NMIBC group (1.98–2.45 cm) (P < 0.05). The specificity and positive predictive values (PPV) of VI‐RADS_TCL were 82.46%–87.72% and 90.91%–91.59%, which were significantly greater than VI‐RADS score (P < 0.05). Additionally, 52.17%–55.88% NMIBC lesions with VI‐RADS 3 were downgraded to 3F by using VI‐RADS_TCL. Data Conclusion The proposed MRI strategy could reduce the false‐positive rate of lesions with a VI‐RADS score of 3 while retaining sensitivity. Evidence Level 4 Technical Efficacy 2