The role of PET/CT in evaluation of Facet and Disc abnormalities in patients with low back pain using (18)F-Fluoride.
BACKGROUND
Bone scintigraphy including Single Photon Emission Computed Tomography (SPECT) is known for its role in the diagnosis of low back pain disorders. Positron Emission Tomography (PET) with (18)F (Flouride-18) as a tracer can be used to carry out bone scans with improved image quality. With the addition of CT, simultaneous PET/CT fused images provide more accurate anatomical details. The objectives of this work are to assess the use of (18)F-PET/CT in patients with back pain and suspected facetogenic pain, and to find the frequency of facet arthropathy versus disc disease abnormalities.


METHODS
67 patients who presented with back pain underwent routine X-ray, CT and/or MRI, which failed to identify a clear cause, were referred to (18)F-PET/CT. Among the main group, a subset of 25 patients had previous spine surgery consisting of laminectomy or discectomy (17 patients) and lumbar fusion (8 patients). The PET/CT scan was acquired on a GE VCT 64-Slice combined scanner. Imaging started 45-60 minutes after administration of 12-15 mCi (444-555 MBq) of (18)F-Fluoride. The PET scan was acquired from the skull base through the inguinal region in 3D mode at 2 minutes/bed. A lowresolution, non-contrast CT scan was also acquired for anatomic localization and attenuation correction.


RESULTS
The (18)F-PET/CT showed abnormal uptake in the spine in 56 patients, with an overall detection ability of 84%. Facet joints as a cause of back pain was much more frequent (25 with abnormal scans). One-third (36%) of the patients showed multiple positive uptake in both facet joints and disc areas (20/56). The patients were further divided into two groups. Group A consisted of 42 patients (63%) with back pain and no previous operative procedures, and the (18)F-PET/CT showed a high sensitivity (88%) in identifying the source of pain in 37/42 patients. Group B included 25 patients (37%) with prior lumbar fusion or laminectomy, in which the PET/CT showed positive uptake in 76% (19/25 patients). (18)F-PET/CT showed positive uptake in all patients (100%) with a history of pain after lumbar fusion, while in the laminectomy subgroup only 11 cases (65%) showed positive focal uptake.


CONCLUSIONS
(18)F-PET/CT has a potential use in evaluating adult patients with back pain. It has a promising role in identifying causes of persistent back pain following vertebral surgical interventions.
Gamie
Sherief
S
Department of Radiotherapy, Alexandria University, Alexandria, Egypt.
El-Maghraby
Tarek
T
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001175:Arthrography / Q000379:methods; D005260:Female; D005459:Fluorides; D005462:Fluorine Radioisotopes; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000150:complications* / Q000175:diagnosis*; D007592:Joint Diseases / Q000150:complications* / Q000175:diagnosis*; D017116:Low Back Pain / Q000175:diagnosis* / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D014057:Tomography, X-Ray Computed / Q000379:methods*; D021801:Zygapophyseal Joint / Q000473:pathology
D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals; D005459:Fluorides