[Application evaluation of multi-parametric MRI in the diagnosis and differential diagnosis of early prostate cancer and prostatitis].

Objective To evaluate the value of multi-parametric MRI (Mp-MRI) in the diagnosis and differential diagnosis of early prostate cancer(PCa) in the peripheral zone(PZ) and low T2WI signal intensity of prostatitis. Methods A total of 40 patients with PZ early PCa and 37 with prostatitis of hypointense T2WI signal in PZ were retrospectively analyzed, which were collected from the General Hospital of Ningxia Medical University from Janurary 2009 to June 2015, who underwent T2WI, DWI, and DCE-MRI examination and all patients were confirmed by pathology. All the data was transferred to GE Advanced Workstation AW4.3, the indexes divided into cancerous and prostatitis regions were calculated by Functool2 of signal intensity-time(SI-T) curve and ADC value, to calcuate the time to minimum(Tmax), the whole enhancment degree (SImax). ROC cure was used to determine the cutoff value for PCa detection with the ADC value. Result On T2WI, 57.5% of PCa (23/40) showed focal nodular homogeneous low signal intensity, 70.3% of prostatitis(26/37) showed diffuse inhomogeneous low signal intensity. DCE-MRI, the distribution of curve types for malignant tumors was type Ⅰ 2.5%(1/40), typeⅡ32.5%(13/40) and type Ⅲ 65.0% (26/40). While the numbers for prostatitis was type Ⅰ 16.2%(6/37) , type Ⅱ 56.8% (21/37) and type Ⅲ 27.0% (10/37)respectively.The patterns of curve types in malignant lesions were different from benign lesions significantly(χ2 =12.32, P<0.01). The mean values of Tmax, SImax in cancerous and prostatitis regions were (17.96±2.91)s, 1.76%±0.23% and (21.19±3.59)s, 1.53%±0.18%, respectively (t=5.37, 6.10; P<0.01). On DWI, The mean ADC values in cancerous and prostatitis regions were (0.95±0.13)×10-3 mm2/s and (1.12±0.13)×10-3 mm2/s, respectively (t=7.10, P<0.01). According to the ROC analysis, when the cutoff value was 1.01×10-3 mm2/s, the early PCa of diagnostic sensitivity, specificity and accuracy was 79.1%, 72.7% and 76.1% respectively. Conclusion Combined with morphology and signal characteristics of conventional T2WI, DWI and DCE-MRI improve the power of MR imaging in discriminating prostatitis from early PCa. Key words: Prostatic neoplasms; Magnetic resonance imaging; Dynamic contrast enhancement; Diffusion-weighted imaging