Tumor recurrence is a major cause of nasopharyngeal carcinoma (NPC) treatment failure. Diffusion-weighted imaging (DWI) is used for a variety of cancers, but few data are available for NPC.The aim of the study was to investigate the DWI features of recurrent NPC after radiotherapy and apparent diffusion coefficient (ADC) thresholds for the diagnosis of recurrent NPC.This was a retrospective study of 160 patients with NPC treated by radiotherapy at the Cancer Hospital affiliated to Guangxi Medical University from May 2012 to March 2015. The patients were divided into the local recurrence (n = 39), fibrosis (n = 51), clivus recurrence (n = 22), and clivus nonrecurrence (n = 48) groups. The patients underwent magnetic resonance imaging (MRI), enhanced MRI, and DWI. Receiver operating characteristics curves were used to determine sensitivity, specificity, and negative predictive values.ADC values were significantly different between the recurrence and fibrosis groups (P < .0001). Using ADC threshold values of 0.887 × 10 mm/s for local recurrence, the area under the curve (AUC) of DWI was 0.967 (87.2% sensitivity and 94.1% specificity), compared with 0.732 for routine MRI (71.8% sensitivity and 74.5% specificity) (P < .001). Using ADC threshold values of 1.018 × 10 mm/s for the diagnosis of clivus recurrent NPC, the AUC of DWI was 0.984 (95.5% sensitivity and 91.7% specificity) compared with 0.558 for routine MRI (63.6% sensitivity and 47.9% specificity) (P < .001).DWI has a higher diagnostic value for recurrent NPC than MRI. DWI can increase the diagnosis sensitivity and specificity of locally recurrent NPC.

To determine the diagnostic value of computed tomography (CT) for prediction of microvascular invasion (MVI) in hepatocellular carcinoma (HCC). Preoperative CTs for 160 patients with 57 MVI-positive and 103 MVI-negative HCCs diagnosed by surgical pathology were reviewed retrospectively. CT parameters and serum α-fetoprotein (AFP) level were analyzed in SPSS 16.0. Although univariate analysis showed that tumor size (P = .012), grade (Z = -2.114, P = .034), and peritumoral enhancement (χ = 4.464, P = .035) were associated with MVI, multiple logistic regression analysis showed that capsular invasion (odds ratio [OR] = 23.469, P < .001), margins (OR = 6.751, P < .001), and serum AFP level (OR = 1.001, P = .038) were associated with MVI in HCC (P < .05). Radiographic hepatic capsular invasion and nonsmooth tumor margins identified by preoperative CT images, along with AFP levels greater than 232.2 ng/mL, are important predictors of MVI.