Noninvasive Differentiation of Obstructive Azoospermia and Nonobstructive Azoospermia Using Multimodel Diffusion Weighted Imaging

Rationale and objectives: To evaluate the diagnostic performance of parameters derived from multimodel diffusion weighted imaging (monoexponential, stretched-exponential diffusion weighted imaging and diffusion kurtosis imaging [DKI]) from noninvasive magnetic resonance imaging in distinguishing obstructive azoospermia (OA) from nonobstructive azoospermia (NOA).

Materials and methods: Forty-six patients with azoospermia were prospectively enrolled and classified into two groups (21 OA patients and 25 NOA patients). The multimodel parameters of diffusion-weighted imaging (DWI; apparent diffusion coefficient [ADC], distributed diffusion coefficient [DDC], diffusion heterogeneity [α], diffusion kurtosis diffusivity [D_app], and diffusion kurtosis coefficient [K_app]) were derived. The diagnostic performance of these parameters for the differentiation of OA and NOA patients were evaluated using receiver operating characteristic analysis. The area under the curve (AUC) was calculated to evaluate the diagnostic accuracy of each parameter.

Results: All the parameters (ADC, α, DDC, D_app, and K_app) values were significantly different between OA and NOA (P < 0.001 for all). For the differentiation of OA from NOA, K_app showed the highest AUC value (0.965), followed by DDC (0.946), D_app (0.933), ADC (0.922), and α (0.887). K_app had a significantly higher AUC than the conventional ADC (P < 0.05).

Conclusion: Parameters derived from multimodels of DWI have the potential for the noninvasive differentiation of OA and NOA. The K_app value derived from the DKI model might serve as a useful imaging marker for the differentiation of azoospermia.