Diffusion-weighted Magnetic Resonance Imaging in Non-traumatic Vertebral Collapse: A Relook Into Its Utility in Making the Diagnosis in a Population Where Infections of Spine Are a Common Cause

Abstract

Aim: Magnetic resonance imaging (MRI) is the imaging investigation of choice in vertebral collapse. In this study, we considered various MRI features and appearance based on morphological features, signal intensity, contrast enhancement characteristics, and diffusion-weighted imaging (DWI) of various types of non-traumatic vertebral collapse for differentiating benign from malignant causes and its role in differentiating cases of infectious causes of vertebral collapse from malignant causes.

Materials and methods: Between November 2014 to November 2016 a total of 100 consecutive patients from the MRI centre of JN Medical College and Hospital, Aligarh, were evaluated for the study. Inclusion criteria included patients presenting with backache, limb weakness, and fever who had undergone radiography of the spine that showed features of collapse. All patients underwent MRI on a 1.5 T MR Scanner. Coronal, sagittal and axial spine images were obtained using T1 weighted, T2 weighted, short tau inversion recovery, T1 postcontrast, and DWI sequences.

Results: In our study, we found different causes of non-traumatic vertebral collapse that were broadly categorized as benign or malignant. The benign causes were further sub-categorized into osteoporotic or infectious based on morphological features, signal intensity characteristics, and DWI. However, on DWI, the patients with infective collapse showed mean apparent diffusion coefficient values of 884 × 10^-6 mm²/s ranging between 700 and 1,100 × 10^-6 mm²/s between those of malignant and benign osteoporotic collapse, with significant overlap. The statistical difference between the malignant and infective cases, as well as between osteoporotic and infective cases, was not found to be statistically significant (P > .05).

Conclusion: MRI plays a key role in establishing the cause of vertebral collapse, classifying it as either benign or malignant. DWI, although described in various studies as highly sensitive in differentiating benign osteoporotic and malignant collapse, was found to be good in differentiating only osteoporotic from malignant collapse, with the infectious cases proving to be a grey zone with significant overlap of quantitative diffusion findings.

Keywords: MRI; Vertebral collapse; diffusion weighted imaging.