Comparison of MRI, [18F]FDG PET/CT, and 99mTc-UBI 29-41 scintigraphy for postoperative spondylodiscitis—a prospective multicenter study

Abstract

Purpose Postoperative infection still constitutes an important complication of spine surgery, and the optimal imaging modality for diagnosing postoperative spine infection has not yet been established. The aim of this prospective multicenter study was to assess the diagnostic performance of three imaging modalities in patients with suspected postoperative spine infection: MRI, [18F]FDG PET/CT, and SPECT/CT with 99mTc-UBI 29-41. Methods Patients had to undergo at least 2 out of the 3 imaging modalities investigated. Sixty-three patients enrolled fulfilled such criteria and were included in the final analysis: 15 patients underwent all 3 imaging modalities, while 48 patients underwent at least 2 imaging modalities (MRI + PET/CT, MRI + SPECT/CT, or PET/CT + SPECT/CT). Final diagnosis of postoperative spinal infection was based either on biopsy or on follow-up for at least 6 months. The MRI, PET/CT, and SPECT/CT scans were read blindly by experts at designated core laboratories. Spine surgery included metallic implants in 46/63 patients (73%); postoperative spine infection was diagnosed in 30/63 patients (48%). Results Significant discriminants between infection and no infection included fever (P = 0.041), discharge at the wound site (P < 0.0001), and elevated CRP (P = 0.042). There was no difference in the frequency of infection between patients who underwent surgery involving spinal implants versus those who did not. The diagnostic performances of MRI and [18F]FDG PET/CT analyzed as independent groups were equivalent, with values of the area under the ROC curve equal to 0.78 (95% CI: 0.64–0.92) and 0.80 (95% CI: 0.64–0.98), respectively. SPECT/CT with 99mTc-UBI 29-41 yielded either unacceptably low sensitivity (44%) or unacceptably low specificity (41%) when adopting more or less stringent interpretation criteria. The best diagnostic performance was observed when combining the results of MRI with those of [18F]FDG PET/CT, with an area under the ROC curve equal to 0.938 (95% CI: 0.80–1.00). Conclusion [18F]FDG PET/CT and MRI both possess equally satisfactory diagnostic performance in patients with suspected postoperative spine infection, the best diagnostic performance being obtained by combining MRI with [18F]FDG PET/CT. The diagnostic performance of SPECT/CT with 99mTc-UBI 29-41 was suboptimal in the postoperative clinical setting explored with the present study.

Lumbar Spine Posttherapeutic Imaging

“…Whereas MRI has high diagnostic accuracy for infection in the nonoperated spine, the diagnosis of spondylodiskitis is more challenging in a postoperative context. 36 Indeed, there are very often edematous changes and contrast enhancement of the vertebral plates after diskectomy (►Fig. 6a, b).…”

“…However, the best diagnostic images are obtained by combining MRI with 18 F-FDG-PET/CT. 36 Abnormal Late Postoperative Imaging Findings Epidural Fibrosis and Hernia Recurrence If the symptomatology reappears after a pain-free interval, the main complication is hernia recurrence. The distinction between epidural fibrosis and recurrent or residual herniated disk material is one of the most important challenges of posttherapeutic lumbar spinal imaging.…”

Radionuclide Imaging of Invasive Fungal Disease in Immunocompromised Hosts

“…In addition to radiolabeled anti-fungal drugs targeting specific molecular structures of the fungi, other non-specific antimicrobial peptides have been explored for their possible application as noninvasive probes for IFD imaging [26,141]. Ubiquicidine 29-41 (UBI 29-41) radiolabeled with 99m Tc for SPECT or 68 Ga for PET imaging have been extensively used for pyogenic skeletal and soft tissue infections [142][143][144]. [ 99m Tc]Tc-UBI 29-41 has been reported to accumulate at sites of Aspergillus fumigatus and Candida albicans infections [124,145].…”

Diagnostic accuracy of fluorine-18 fluorodeoxyglucose positron emission tomography for suspected primary and postoperative pyogenic spondylitis

“…This devastating disorder accounts for 2–7% of all cases of musculoskeletal infection [ 2 ], and along with the aging of the population, the prevalence of pyogenic spondylitis is increasing [ 3 , 4 ]. Meanwhile, postoperative spondylitis constitutes an important complication of spine surgery, which often leads to hospitalization/reoperation, increased morbidity and high economic burden [ 5 ]. Most patients with pyogenic spondylitis can achieve a satisfactory prognosis with conservative treatment at the early stage, but for patients with spinal cord or cauda equina compression and progressive neurological deficits, surgical intervention is indicated [ 5 ].…”

“…Meanwhile, postoperative spondylitis constitutes an important complication of spine surgery, which often leads to hospitalization/reoperation, increased morbidity and high economic burden [ 5 ]. Most patients with pyogenic spondylitis can achieve a satisfactory prognosis with conservative treatment at the early stage, but for patients with spinal cord or cauda equina compression and progressive neurological deficits, surgical intervention is indicated [ 5 ]. Early and accurate identification of pyogenic spondylitis is necessary to initiate timely management and improve the long-term outcome.…”