18F-FDG hybrid PET in patients with suspected spondylitis

Abstract

This study investigated the value of fluorine-18 2'-deoxy-2-fluoro- D-glucose (FDG) imaging with a double-headed gamma camera operated in coincidence (hybrid PET) detection mode in patients with suspected spondylitis. Comparison was made with conventional nuclear medicine imaging modalities and magnetic resonance imaging (MRI). Sixteen patients with suspected spondylitis (nine male, seven female, mean age 59 years) prospectively underwent FDG hybrid PET (296 MBq) and MRI. For intra-individual comparison, the patients were also imaged with technetium-99m methylene diphosphonate (MDP) (555 MBq) ( n=13) and/or gallium-67 citrate (185 MBq) ( n=11). For FDG hybrid PET, two or three transverse scans were performed. Ratios of infected (target) to non-infected (background) (T/B) vertebral bodies were calculated. MR images were obtained of the region of interest. Patients found positive for spondylitis with MRI and/or FDG hybrid PET underwent surgical intervention and histological grading of the individual infected foci. Twelve out of 16 patients were found to be positive for spondylitis. Independent of the grade of infection and the location in the spine, all known infected vertebrae ( n=23, 9 thoracic, 12 lumbar, 2 sacral) were detected by FDG hybrid PET. T/B ratios higher than 1.45+/-0.05 (at 1 h p.i.) were indicative of infectious disease, whereas ratios below this value were found in cases of degenerative change. FDG hybrid PET was superior to MRI in patients who had a history of surgery and suffered from a high-grade infection in combination with paravertebral abscess formation ( n=2; further computed tomography was needed) and in those with low-grade spondylitis ( n=2, no oedema) or discitis ( n=2, mild oedema). False-positive 67Ga citrate images ( n=5: 2 spondylodiscitis, 1 aortitis, 1 pleuritis, 1 pulmonary tuberculosis) and 99mTc-MDP SPET ( n=4: 1 osteoporosis, 2 spondylodiscitis, 1 fracture) were equally well detected by FDG hybrid PET and MRI. No diagnostic problems were seen in the other patients ( n=5). In this study, FDG hybrid PET was superior to MRI, 67Ga citrate and (99m)Tc-MDP, especially in patients with low-grade spondylitis (as compared with MRI), adjacent soft tissue infections (as compared with 67Ga citrate) and advanced bone degeneration (as compared with 99mTc-MDP).

Imaging findings of Pott’s disease

“…Combined with Diphosphonates it can efficiently detect both osseous and soft tissue infection [32,35,36], with a sensitivity of 90 % and specificity of 78 %, [31,37]. It has demonstrated its value in therapeutic response and also in the suspicion of a re-activation [35,39]. Its positive interpretation is based on the coincidence of enhanced activity of both techniques in the same lesion or on a higher Gallium uptake where spatial discordance exists, e.g.…”

“…10). It is sensitive to chronic infections and specific in spondylitis [39], and it may differentiate infectious from non-infectious end-plate processes. Considering the low glucose consumption normally found in bone marrow and that the FDG uptake depends on the inflammatory/infectious activity, vertebral osteomyelitis can be easily detected, therefore a negative study will almost certainly exclude it.…”

“…Compared to MRI, 18 F-FDG is not hampered by metallic artifacts [32]. Gratz [39] reported its superiority to MRI in detecting spondylitis, to Gallium in evaluating paraspinal abscesses, and to bone scan in differentiating advanced degenerative processes from infection. It may be useful in the follow-up, because FDG uptake normalization after treatment takes 3-4 months.…”

Vertebral endplate signal changes (Modic change): a systematic literature review of prevalence and association with non-specific low back pain

“…In all these cases, consensus was obtained without difficulties by authors 1 and 5. A total of 60 papers were excluded after review; 27 as they dealt with specific LBP conditions ( Table 2) and 33 for other reasons: one review article [55], four case reports [7,27,129,148], one double publication [90], one of two studies reporting data from the same study sample [80], ten for evaluating signal changes other than those related to the endplate [6,20,51,53,71,113,116,139,146,150], and eight articles because they did not report the exact numbers needed to calculate the prevalence rates of VESC [4,10,109,110,114,122,133,141]. Finally, eight articles were excluded because the study samples were selected on the basis of the presence of VESC [41, 50,56,63,68,134,137,149].…”

Radiopharmaceuticals for imaging chronic lymphocytic inflammation

“…The standardised uptake values also correlated with serum CRP (C-reactive protein) and MMP-3 (matrix metalloproteinase-3) levels. Studies in the patients with spondylodiscitis proved FDG PET to be superior to MRI,67 Gacitrate scintigraphy and three phase bone scan for visualization (Gratz et al, 2002;Schmitz et al, 2001). Moreover, FDG PET is also able to differentiate between mild infection and degenerative changes (Stumpe et al, 2002).…”