[Value of multiple b-value diffusion-weighted imaging for differentiation of benign and malignant pulmonary masses]

To explore the value of multiple b-value diffusion-weighted imaging (DWI) for differentiation of benign and malignant pulmonary masses.

Thirty-eight patients were examined by routine sequences and DWI pulse sequence. DWI was acquired through a single-shot echo-planar imaging combined with a respiratory-triggered mode and parallel acquisition. Nine b values ranging from 0 to 1500 s/mm(2) (0, 50, 100, 150, 200, 400, 600, 1000, 1500 s/mm(2)) were used. The intravoxel incoherent motion model was applied to estimate pure diffusion coefficient D, perfusion-related diffusion coefficient D(*), and perfusion fraction f. Mann-Whitney U test was used to compare all measured parameters between benign and malignant groups. The diagnostic performance of the related parameters was evaluated with receiver operating characteristics (ROC) analysis.

Of these 38 patients, 30 were pathologically confirmed and 8 were diagnosed based on clinical data. There were 23 lung malignant masses and 15 benign lesions. A significant reduction of D was found in malignant group than in benign group (Z=3.308, P=0.001), while no significant differences in D(*)(Z=1.646, P=0.100) and f(Z=1.254, P=0.210) were observed between the two groups. The area under the ROC curve for D value (0.839) was largest. When the cutoff value was selected as 0.90×10(-3) mm(2)/s, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of diagnosing malignant masses were 95.7%, 80.0%, 90.9%, 91.7%, and 88.9%,respectively.

The D value in multiple b-value DWI has certain significance in differentiating the benign and malignant pulmonary masses and has the best diagnostic efficiency.