The Efficiency of Diffusion-weighted Magnetic Resonance Imaging in the Differentiation of Malign and Benign Cavitary Lung Lesions

Abstract

Purpose: 

The present study investigates the diagnostic efficiency of apparent diffusion coefficient (ADC) values in differentiating between malignant and benign cavitary lesions on diffusion-weighted magnetic resonance imaging (DWI).

Materials and Methods: 

This prospective study included 45 consecutive patients identified with a cavitary lung lesion with a wall thickness of ≥5 mm on thoracic computed tomography in our clinic between 2020 and 2022, and who underwent thoracic DWI within 1 week of their original computed tomography. ADC measurements were made on DWI by drawing a region of interest manually from the cavity wall, away from the lung parenchyma in the axial section where the lesion was best demonstrated. The patients were then classified into benign and malignant groups based on the pathology or clinico-radiologic follow-up.

Results: 

The sample included 29 (64.4%) male and 16 (35.6%) female patients, with a mean age of 59.06±17.3 years. Included in the study were 1 patient with 3 and 3 patients with 2 cavitary lesions each, with a total for the sample of 50 cavitary lesions. There were 23 (46%) malignant and 27 (54%) benign cavitary lung lesions. The mean ADC value (×10⁻³ mm²/s) of the malignant and benign cavitary lesions was 0.977±0.522 (0.511 to 2.872) and 1.383±0.370 (0.930 to 2.213), respectively. The findings were statistically significant using an independent samples t test (P=0.002). The mean wall thickness of the malignant and benign lesions was 12.47±5.51 mm (5 to 25 mm) and 10.11±4.65 mm (5 to 22 mm), respectively. Although malignant cavities had a higher mean wall thickness than benign cavities, the difference was statistically insignificant (P=0.104).

Conclusion: 

A significant difference was identified between the ADC values measured in DWI of the malignant and benign cavitary lung lesions. DWI, a noninvasive and rapid imaging method, can provide useful information for the differential diagnosis of cavitary lesions and can minimize unnecessary biopsies.