Lumbar Spine MR Imaging : Relation Between Edema Like Signal in the Posterior Soft-Tissue and Body Mass Index

Abstract

Background: It is not uncommon to encounter edema like signal within the soft tissue of the posterior lumbar region in MRI of the spine; however the exact explanation of such edema is not established yet. Objectives: To find out relationship between edema like lesion in the soft tissue of the posterior lumbar region on spine MRI with BMI, age and gender. Patients and Methods: Lumbar Spine MRI of 288 outpatients suspected to have disc disease ( 150 females and 138 males ) performed on 1.5 Tesla facility was evaluated. Subjects with systemic or local disease likely to produce edema were excluded to obtain healthier subjects. The scans were reviewed for presence, site, and degree of High T2 edema like signal within the posterior lumbar soft tissue. The subjects were divided into four subgroups according to BMI and two groups according to their age (≤50 or>50 years old). The edema was scored from 0-5 based on its length relative to vertebral-body height. Correlation between the presence and extent of edema was made with BMI, age and gender. Results: Among the 288 cases, 116 (40%) patients had lumbar soft tissue edema. Association was found between the degree of edema and BMI ( P= .001) and with age ( P= .041) . The presence of edema was noticed to be significantly more among women (P=.045) , while the average level of edema epicenters was approximately similar ( L3.6 and L 4 consequently, P = .58). Conclusion: There is a positive relationship between the frequency and extent of posterior lumbar soft tissue edema with BMI and age .