Validation of topographic hybrid single-photon emission computerized tomography with computerized tomography scan in patients with and without nonspecific chronic low back pain. A prospective comparative study.

Background Context: The evidence for the treatment for nonspecific chronic low back pain (ns CLBP) is very weak. Besides the complexity of the pain experience, a good biological marker or tool enabling identification of a pain generator is lacking. Hybrid imaging, combining single-photon emission computerized tomography (SPECT) with computerized tomography (CT) scan, has been proposed as useful in the diagnostic workup of patients with CLBP.

Purpose: To evaluate the sensitivity of SPECT-CT in patients with ns CLBP (Group I) as compared with patients without CLBP (Group II).

Study Design: A prospective comparative study.

Patient Sample: Two hundred patients were enrolled: 96 in Group I and 104 in Group II.

Outcome Measures: Only the physiological measurement of the incidence of hot spots was performed. The hot spots were rated as follows: 0=normal; 1=slightly colored (no hot spot on whole-body bone scan); and 2=clear hot spot (can be identified on the whole-body bone scan and confirmed on SPECT). To analyze the interobserver agreement when using this scoring system, a second independent reading was performed for 50 randomly chosen records.

Methods: Two hundred patients divided into two groups were referred to the department of Medical and Molecular Imaging for a topographic SPECT-CT. The first group consisted of patients with ns CLBP, diagnosed by a neurosurgeon. The control group consisted of patients referred for SPECT-CT for non-spinal conditions. Hot spots were assessed for all patients. A second independent reading, blinded for the results of the first reader, was performed on 25 randomly selected patients in each group. This study was investigator initiated, and no funding was received. None of the authors or their proxies have a potential conflict of interest.

Results: The odds of finding a normal image in the control group are 2.05 times higher than in Group I. The sensitivity score equals 2.37, meaning that the probability of detecting a hot spot (levels 1 or 2) is more than two times higher in Group I. When focusing on level 2 hot spots only, this score rises to 7.02, indicative of a high sensitivity.

Conclusions: Single-photon emission computerized tomography with computerized tomography might have potential in the diagnostic workup of patients with ns CLBP, owing to its higher sensitivity when compared with other advanced medical imaging modalities.