Hybrid single-photon emission computed tomography bone imaging for the evaluation of non-specific lower back pain

Abstract

Background

This is a single-center retrospective study designed to assess the correlation between the location of “hots spots” on single-photon emission computed tomography (SPECT) and the severity of joint degeneration on computed tomography (CT), in addition to understanding whether these hot spots correlate with the pain generating sites causing the non-specific lower back pain.

Methods

All patients who had undergone hybrid SPECT-CT imaging of the lower back over a one-year period at our institution were identified. Twenty joints were assessed from each patient. Joints for assessment were chosen from the intervertebral discs, facet (zygapophysial) and sacroiliac joints. Diagnostic accuracy was assessed using receiver operating characteristic (ROC) curves and quantified using the area under the receiver operating characteristic curve (AUROC).

Results

Over a one-year period, 111 patients were identified, with the primary indication being non-specific lower back pain in 73 (66%). Hot spots were observed on SPECT in 79% of patients, with 86% having some degree of degeneration in at least one joint on CT. Degeneration was found to be significantly associated with the presence of hot spots for the majority of joints, with the strongest association seen in the L3/L4 intervertebral joint, for which the rates of hot spots were 1% for grade 0, 26% for grade 1 and 78% for grades 2–3 (AUROC: 0.91, p<0.001). Neither the presence of hot spots nor degeneration were found to be significantly predictive of non-specific lower back pain for any of the joints considered.

Conclusions

Hot spots identified on SPECT are correlated with the presence of degeneration on CT but have limited diagnostic ability to identify potential causes of non-specific lower back pain.