Value of intravoxel incoherent motion diffusion-weighted MR imaging in differentiating malignant from benign pulmonary lesions: a meta analysis

Previous studies have indicated that intravoxel incoherent motion model (IVIM) of magnetic resonance imaging (MRI) shows great potential to differentiate malignant from benign lung lesions using various parameters such as pure diffusion coefficient (D), pseudo-diffusion coefficient (D*) and perfusion fraction (f). However, these studies showed inconsistent results. The aim of this meta-analysis was to evaluate the overall diagnostic value of the IVIM model in distinguishing malignant from benign lung lesions. A literature search was conducted in Pubmed, Web of Science, CNKI and Wanfang Data to identify relevant available studies. We compared IVIM parameters between malignant and benign lung lesions and determined sensitivities and specificities across studies and constructed summary receiver operating characteristic SROC) curves. The pooled sensitivities were 0.78 (0.68-0.86), 0.74 (0.65-0.82) and 0.84 (0.74-0.91) for ADC, f and D, respectively. The pooled specificities were 0.83 (0.70-0.93), 0.52 (0.39-0.65) and 0.60 (0.46-0.73) for ADC, f and D, respectively. The AUCs of the SROC were 0.8748, 0.6774 and 0.7868 for ADC, f and D, respectively. The combined weighted mean difference (WMD) suggested the mean values of ADC, D and f in lung cancer were significantly lower than in benign lung diseases. However, there were no significant differences between lung cancer and benign lung diseases for D* value. The IVIM model may be helpful to discriminate malignant from benign lung lesions. Large-scale randomized controlled trials regarding IVIM in characterizing focal pulmonary lesions are still required to be conducted.