Interest of [ 18 F]fluorodeoxyglucose positron emission tomography/computed tomography for the diagnosis of relapse in patients with spinal infection: a prospective study

Abstract

Relapse after treatment of a spinal infection is infrequent and difficult to diagnose. The aim of this study was to assess the diagnostic performance of [(18)F]fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in this setting. Thirty patients (21 men, nine women; median age 61.2 years) with a suspected spinal infection relapse were prospectively included between March 2010 and June 2013. The initial diagnosis of spinal infection was confirmed by positive bacterial cultures. The patients underwent [(18)F]FDG PET/CT and magnetic resonance imaging (MRI) 1 month after antibiotic treatment interruption. PET/CT data were interpreted both visually and semi-quantitatively (SUVmax). The patients were followed for ≥12 months and the final diagnosis of relapse was based on new microbiological cultures. Seven patients relapsed during follow up. Sensitivity, specificity, positive predictive value and negative predictive value were 66.6%, 61.9%, 33.3% and 86.6%, respectively for MRI and 85.7, 82.6, 60.0 and 95.0 for PET/CT. Although these values were higher for PET/CT than for MRI, the difference was not statistically significant (p=0.3). [(18)F]FDG PET/CT may be useful for diagnosing a relapse of spinal infections, in particular if metallic implants limit the performance of MRI.

Added value of [18F]fluorodeoxyglucose positron emission tomography/computed tomography for the diagnosis of post-operative instrumented spine infection

“…Previous study focusing mainly on hematogenous spinal infections found better diagnostic values than in our study [14,16,23,24]. Studies which assessed the diagnostic value of PET/CT in postoperative spinal infections found similar diagnostics values to those in our study [13,19]. De Winter et al found a sensitivity at 100% and a specificity at 81% for PET without CT.…”

“…Lecture parameters of PET imaging were studied in a previous paper [13]. Briefly, suggestive signs of infection during PET/CT assessment included: (i) uptake location (linear or disciform uptake pattern in intervertebral disc space with/without involvement of endplates, bone involvement and/or surrounding soft tissue abscesses, involvement of arthrodesis material), (ii) uptake pattern (focal or multifocal, higher uptake in the side with suspected infection than in the contralateral side), (iii) uptake intensity estimated by the ratio of the maximum standardized uptake value (SUV max ) in the suspected foci over the SUV max of a considered normal region (for example adjacent disc without abnormality) with a ratio ≥2.3.…”

“…Furthermore, numerous artifacts due to the metallic implants do prevent a quality performance of the analysis [9]. In the literature, [ 18 F]fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) has shown excellent diagnostic performances for the detection of spinal infection, with a sensitivity between 86-100% and specificity 65-100% [11][12][13][14][15][16][17][18][19]. Other nuclear medicine techniques such as white blood cells scintigraphy are not performing well during spine infections [12].…”

Comparison of the Diagnostic Value of MRI and Whole Body 18F-FDG PET/CT in Diagnosis of Spondylodiscitis

“…Discordant results were found in 6 of 56 patients for whom the MRI was positive, but the 18 F-FDG PET/CT did not reveal any lesions. In four of them, the diagnosis of spondylodiscitis was confirmed and false-negative 18 F-FDG PET/CT results were probably due to a weak infection characterized only by epidural involvement, whereas the low 18 F-FDG uptake may have been related to the different immune reaction caused by the various etiological agents [22,32,33]. In the remaining two patients, spondylodiscitis was finally not confirmed by follow-up and the false-positive MRI results were due to the presence of severe degenerative disc disease [22].…”

Joint EANM/ESNR and ESCMID-endorsed consensus document for the diagnosis of spine infection (spondylodiscitis) in adults

“…Published data indicate that [ 18 F]FDG-PET/CT is superior to 67 Ga for the diagnosis of spinal infection and paraspinal soft tissue infection [82], and should be used in selected cases as an alternative to MRI [3,61,[94][95][96][97][98][99][100][101][102][103][104][105][106][107][108][109]. All studies in which a comparison between MRI and [ 18 F]FDG-PET/CT was performed have shown that a combination of the two techniques detects spinal infection in 100% of patients [102,110,111].…”