Diffusion Weighted Magnetic Resonance Imaging for the Characterization of Solitary Pulmonary Lesions

Abstract

Background:We evaluated the differential diagnosis of solitary pulmonary lesions on magnetic resonance imaging. Aims: To investigate the value of diffusion weighted imaging on the differential diagnosis of solitary pulmonary lesions. Study Design: Randomized prospective study. Methods: This prospective study included 48 solitary pulmonary nodules and masses (18 benign, 30 malignant). Single shot echo planar spin echo diffusion weighted imaging (DWI) was performed with two b factors (0 and 1000 s/mm 2 ). Apparent diffusion coefficients (ADCs) were calculated. On diffusion weighted (DW) trace images, the signal intensities (SI) of the lesions were visually compared to the SI of the thoracic spinal cord using a 5-point scale: 1: hypointense, 2: moderately hypointense, 3: isointense, 4: moderately hyperintense, 5: significantly hyperintense. For the quantitative evaluation, the lesion to thoracic spinal signal intensity ratios and the ADCs of the lesions were compared between groups.Results: On visual evaluation, taking the density of the spinal cord as a reference, most benign lesions were found to be hypointense, while most of the malignant lesions were evaluated as hyperintense on DWI with a b factor of 1000 s/mm

Diffusion‐weighted MRI of pulmonary lesions: Comparison of apparent diffusion coefficient and lesion‐to‐spinal cord signal intensity ratio in lesion characterization

“…Lung lesions can be characterized on DWI by qualitative (visual assessment of the lesion), semiquantitative (ratio of the lesion to spinal cord signal intensities), and quantitative (ADC measurement) evaluation. Although the qualitative evaluation of the lung lesions has been showed to be successful, the subjectivity of this method may result in variations. The calculated ratio of signal intensity of the lesion to spinal cord (LSR) has been successfully used for differentiation of benign and malignant tumors .…”

“…Satoh et al and Çakir et al qualitatively compared the signal intensity of the nodules with that of spinal cord on DWI, and found that malignant nodules were significantly more hyperintense than benign nodules. Satoh et al evaluated 54 pulmonary nodules and they obtained DWI using the free‐breathing technique and b value of 1000 s/mm 2 .…”

“…Satoh et al and Çakýr et al found that malignant nodules were significantly more hyperintense than benign nodules on DWI. Moreover, LSR has also been shown to be useful for the differentiation of lung lesions and prediction of tumor invasiveness . In addition, the subtle changes of diffusion restriction of small foci of a tumor might be averaged out by necrosis or a cystic component of tumor.…”

“…Thoracic applications of DWI techniques are growing and preliminary results are promising . In addition to ADC value, lesion‐to‐spinal cord signal intensity ratio (LSR) has been proposed to be more accurate than mean ADC values on DWI . Satoh et al and Çakýr et al found that malignant nodules were significantly more hyperintense than benign nodules on DWI.…”

“…In addition to ADC value, lesion‐to‐spinal cord signal intensity ratio (LSR) has been proposed to be more accurate than mean ADC values on DWI . Satoh et al and Çakýr et al found that malignant nodules were significantly more hyperintense than benign nodules on DWI. Moreover, LSR has also been shown to be useful for the differentiation of lung lesions and prediction of tumor invasiveness .…”