Introduction
Materials and methods
Patients
Patient | Time since surgery (months) | Imaging resultsa
| Clinical follow-up | Pain scoreb
| Statistical categoryc
| ||||
---|---|---|---|---|---|---|---|---|---|
NaF PET findings | SUVmax | Fusion CT | Findings on surgical exploration | Conservative management | Prior to treatment | At 15-month follow-up | |||
1 | 8 | Abnormal activity around cage and hardware at L4-L5 | 13.4 | Subchondral sclerosis | Cage failure and screw loosening | 4 | 1 | True positive | |
2 | 12 | Increased activity at bone graft | 18.1 | Linear radiolucency at graft | Screw loosening and bone graft fracture | 4 | 2 | True positive | |
Focus at L4 right screw | 20.3 | Radiolucency around screw | True positive | ||||||
3 | 60 | Focus at L3-L4 screw | 12.1 | Radiolucency around screw | L3-L4 screw loosening | 4 | 0 | True positive | |
4 | 12 | Intensely increased activity at left L4 bone graft | 18.5 | Sclerotic changes in bone graft | Paravertebral bone graft fracture | 4 | 1 | True positive | |
5 | 36 | Normal | 6.2 (at cervical screws) | No obvious abnormalities requiring surgery | Regional anesthetic block and clinical surveillance; long-term follow-up without pain | 4 | 0 | True negative | |
6 | 48 | Normal | 5.8 (at upper thoracic screws) | No obvious abnormalities requiring surgery | Regional anesthetic block and clinical surveillance; long-term follow-up without pain with no intervention | 4 | 0 | True negative | |
7 | 26 | Abnormal activity at bone graft right L5-S1 | 22.2 | Heterogeneous bone sclerosis | Pseudoarthrosis (abnormal mobility) in bone graft on right | 4 | 2 | True positive | |
8 | 8 | Abnormal activity at bone graft L5 | 12.8 | Likely fracture on the right side of graft | Paravertebral bone graft fracture and loosening of right screw in S1 | 4 | 0 | True positive | |
Asymmetric focus at right S1 screw | 11.2 | Radiolucency around screw | True positive | ||||||
9 | 12 | Increased uptake around cage at L5-S1 | 13.3 | Subtle increased sclerosis at cage tip | Pseudoarthrosis in the bone graft; fixation cage hardware at L5 loose | 4 | 0 | True positive | |
Abnormal activity at left L5 bone graft | 14.2 | Bone reabsorption in region around graft | True positive | ||||||
10 | 11 | Increased uptake between right paravertebral graft and right iliac bone | 23.5 | Abnormal bone resorption | Poor graft healing and necrosis at right iliac bone causing an abnormal neojoint | 4 | 0 | True positive | |
11 | 36 | Mild increased uptake at right L4 screw within normal limits | 6.9 | Completely normal L4 screw | Regional anesthetic block and clinical surveillance; good clinical response in long term | 4 | 1 | True negative | |
12 | 17 | Mild activity in L2 vertebral body within normal limits | 5.9 | Completely normal L2 vertebral body | Clinical surveillance; improved symptoms; without pain at time of report | 4 | 2 | True negative | |
13 | 4 | Increased uptake in left bone graft L4-L5 | 16.3 | Heterogeneous bone at L4-L5 | Bone graft biopsy revealed normal bone | 4 | N/Ad
| False positive | |
14 | 72 | Increased activity in bone graft at L5-S1 | 21.2 | Arthrosis at facet joints L5-S1 | Pseudoarthrosis at L5-S1 graft site | 4 | 1 | True positive | |
15 | 17 | Borderline abnormal focus at proximal rod on right side of L3 likely within normal limits | 6.2 | Mild osteolysis at L3 | Regional anesthetic block with good clinical response; symptoms resolved without further intervention | 4 | 0 | True negative | |
16 | 96 | Increased uptake in left L5 screw | 7.4 | Lucency around L5 screw | Graft fracture and distal screw loosening | 4 | 0 | True positive | |
Intensely increased activity at L5-S1 bone graft | 13.8 | Possible graft fracture | True positive | ||||||
17 | 13 | Focal increased uptake in proximal cage hardware | 19.8 | Mild linear bone resorption | Posterior approach showed proximal and distal cage loosening | 4 | 1 | True positive | |
18 | 23 | Focal increased uptake in middle of hardware at C4 | 18.7 | Very mild lucency around hardware at C4 | Micromobility and cage loosening consistent with psuedarthrosis at C4 | 4 | 1 | True positive | |
19 | 8 | Increase uptake in cage at C5-C6 | 13.4 | Very mild lucency zone related to bone graft maturation or cage mobility | Cage loosening | 4 | 0 | True positive | |
20 | 24 | Intense focus right side of cage at L5-S1 | 20.7 | Signs of loosening at cage | Follow-up examination showed worsening pain; surgeon’s impression was hardware loosening because new CT scan showed right bone graft reabsorption and lucency at screw; patient averse to surgery | 4 | 1 | True positive | |
Increased uptake in S1 screws | 11.5 | CT with lucency area at S1 screws | True positive | ||||||
21 | 19 | Normal | 7.3 at L4-L5 hardware | No obvious abnormalities requiring surgery | Clinical surveillance; follow-up clinical evaluation showed low back pain related to sacroiliitis unrelated to prior surgery | 4 | 2 | True negative | |
22 | 72 | Intense focus at right L4 screw/bone graft | 21.1 | Subtle cortical resorption around screw/graft area | Vertebral body necrosis at L4-L5 with screw loosening | 4 | 0 | True positive |