SLR - November 2021 - Kelly Bier
The Role of Bone Scintigraphy with SPECT/CT in the Characterization and Early Diagnosis of Stage 0 Charcot Neuroarthropathy
Reference: Ahluwalia R, Bilal A, Petrova N, Boddhu K, Manu C, Vas P, Bates M, Corcoran B, Reichert I, Mulholland N, Kavarthapu V, Vivian G, Edmonds M. The Role of Bone Scintigraphy with SPECT/CT in the Characterization and Early Diagnosis of Stage 0 Charcot Neuroarthropathy. J Clin Med. 2020 Dec 21;9(12):4123.
Level of Evidence: IV
Scientific Literature Review
Review By: Kelly Bier, DPM
Residency Program: Hennepin County Medical Center – Minneapolis, MN
Podiatric Relevance: Charcot Neuroarthropathy (CN) causes severe deformity with patients who develop it. Being able to diagnose it earlier in patients can help prevent these deformities. This study evaluated if SPECT/CT imaging could help identify changes within the foot of patients with suspected clinical CN in stage 0.
Methods: Included were diabetics with a red, hot, swollen foot without radiographic evidence of deformity and a more than 2 degree Celsius difference in temperature compared to the contralateral foot. Patients underwent SPECT/CT within two weeks of clinical presentation and continued in an offloading below knee cast. The images were evaluated by a Nuclear Medicine Physician, Orthopedic Surgeon and Diabetologist for differences between the limb with active CN and the contralateral limb. The scans were divided into three groups base on the presence of fractures (Group 1 – fractures present, Group 2 – bony abnormality without fractures, Group 3 – neither). Follow up was a minimum of two years.
Results: A total of 46 patients were included in the study. Twenty-seven patients were in group one, which featured increased blood flow, blood pool, and tracer uptake with evidence of fracture present on CT on the affected limb. The fusion images showed correlation between the areas of fractures and increased tracer uptake but were not consistent for all those in the group. Group 2 included 9 patients with bony abnormalities on CT without evidence of fractures. Eight of the nine patients had increased unilateral blood flow, blood pool and tracer uptake. Group 3 consisted of 10 patients with increased blood flow, blood pool, and tracer uptake but with no CT bony abnormalities present. Four patients total went onto Stage 1 CN and further, with all areas of bony disruption happening at areas of increased tracer uptake previously seen on SPECT.
Conclusions: By using SPECT and CT together, there is evidence of increased blood flow and osteoblastic activity that correlates with fractures and bony abnormalities seen on CT which were not seen on radiographs. In Group 3 there were patients with tracer uptake at the plantar fascia and Achilles insertion without bony abnormalities seen on CT, thus favoring a non-CN diagnosis compared to the other two groups that had fractures or bony abnormalities. However, there is now evidence that CT alone can identify bony abnormalities present in the diabetic population without the use of SPECT. This study demonstrates that even in CN stage 0, there is increased blood flow and bony changes occurring within the bones that warrant treatment. This study does not alter the importance of making a clinical diagnosis of CN stage z0, which should still be treated with a non-weight bearing below knee cast until the inflammatory process resolves.