Diagnostic accuracy of low-dose versus ultra-low-dose CT for lumbar disc disease and facet joint osteoarthritis in patients with low back pain with MRI correlation
To compare the image quality, radiation dose, and diagnostic performance between low-dose (LD) and ultra-low-dose (ULD) lumbar-spine (L-spine) CT with iterative reconstruction (IR) for patients with chronic low back pain (LBP).
In total, 260 patients with chronic LBP who underwent L-spine CT between November 2015 and September 2016 were prospectively enrolled. Of these, 143 underwent LD-CT with IR and 117 underwent ULD-CT with IR. The patients were divided according to their body mass index (BMI) into BMI1 (<22.9 kg/m2), BMI2 (23.0–24.9 kg/m2), and BMI3 (≥25 kg/m2) groups. Two blinded radiologists independently evaluated the signal-to-noise ratio (SNR), qualitative image quality, and final diagnoses (lumbar disc disease and facet joint osteoarthritis). L-spine MRIs interpreted by consensus were used as the reference standard. All data were statistically analyzed.
ULD protocol showed significantly lower SNR for all patients (p < 0.001) except the vertebral bodies and lower qualitative image quality for BMI3 patients (p ≤ 0.033). There was no statistically significant difference between ULD (sensitivity, 95.1–98.1%; specificity, 92.5–98.7%; accuracy, 94.6–98.0%) and LD protocols (sensitivity, 95.6–100%; specificity, 95.5–98.9%; accuracy, 97.4–98.1%), (all p≥0.1) in the BMI1 and BMI2; while dose was 60–68% lower with the ULD protocol. Interobserver agreements were excellent or good with regard to image quality and final diagnoses.
For the BM1 and BMI2 groups, ULD-CT provided an acceptable image quality and exhibited a diagnostic accuracy similar to that of LD-CT. These findings suggest that it is a useful diagnostic tool for patients with chronic LBP who exhibit a BMI of <25 kg/m2.
KeywordsLumbar disc herniation Facet joint osteoarthritis Image quality Diagnostic performance Computed tomography
This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All procedures performed in studies involving human. Participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
Written informed consents from each patient were obtained.
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