Quantitative chemical-shift MR imaging cutoff value: Benign versus malignant vertebral compression – Initial experience

PurposeTo evaluate the diagnostic accuracy of in-phase/opposed-phase quantitative chemical shift magnetic resonance (MR) imaging of the spine and to determine the cutoff value that enables differentiation of malignant from benign compression fractures, in patients with known primary malignancy.Patients and methodsProspective assessment of thirty-two patients with known primary malignancy who presented with vertebral compression fractures, MR imaging of the spine at 1.5 Tesla with standard conventional MR sequences and additional chemical shift (in-phase/opposed-phase) imaging was done. Quantitative image analysis by drawing regions of interest (ROI) on the abnormal marrow of compressed (study group) and adjacent normal vertebra (control group) was also performed in each patient. The signal intensity ratio (SIR) of the marrow was determined by dividing the mean signal intensity on the opposed-phase to the mean signal intensity on the in-phase images and statistical analysis was performed.ResultsMean SIR of benign vertebral compression [0.73 ± 0.07 (range 0.12–1.2)] was significantly lower than malignant SIR values [1.72 ± 0.14 (range 0.8–2.96)] (p < 0.0001; area under the ROC curve, 0.97). The optimal SIR cutoff value for separating benign and malignant vertebral compression was found to be 0.91 with a calculated sensitivity of 93%, specificity of 82% and accuracy of 88%.ConclusionQuantitative chemical shift MR imaging could be a valuable addition to standard MR imaging techniques and represent a rapid problem solving tool in differentiating benign from malignant vertebral compression, especially in patients with known primary malignancies.