Back pain is a prevalent and costly medical problem that often presents a diagnostic and therapeutic challenge. In the thoracic spine, many potential pain generators exist, and the source of pain is frequently difficult to determine. Two of these potentially underrecognized pain generators are the costovertebral and costotransverse joints.
The relationship of 99mTc MDP activity to pain and the utility in directing percutaneous injection seems to vary at different sites throughout the axial skeleton. Therefore, it is important to evaluate each articulation independently.
The role of Nuclear Medicine SPECT/CT Bone Imaging is well established, and the advantages of SPECT/CT in precisely locating and characterizing spinal lesions is well known. This case provides insight into the specific role Bone SPECT/CT imaging plays correctly in localizing D12 left costovertebral joint as a cause of low back pain prior to image guided corticosteroid injections.
This case is an excellent example of a patient benefited by undergoing Bone SPECT/CT imaging prior to previous image guided corticosteroid injections.
47 years-old gentlemen presented with pain along the left lower part of the posterior aspect of the chest of one year duration, which is on and off and was initially treated as radicular pain with some relief. He was evaluated with MRI of the dorso-lumbar spine, which was grossly normal. He is having increased severity of the pain for last two months and unable to lay down straight also because of pain. There is severe local tenderness also along the lower chest wall. He is suspected to have lower intercostal pain syndrome or dorsal neuralgia with secondary tenderness.
Refereed for 99mTc MDP Whole Body Bone Scan & Spect-CT of Dorso-Lumbar Region
Spect-CT fused bone images of dorsal region
Figure 1 - CT SCAN images of left costovertebral articulation of D12 vertebral articulation. It shows sclerosis of D12 left costovertebral joint, reduced joint space with no soft tissue component (figure 1)
Figure 2 - SPECT images of left costovertebral articulation of D12 vertebral articulation.
It shows focal area of abnormally increased tracer uptakes in sclerosis of D12 left costovertebral joint suggesting focally active abnormality (figure 2)
Figure 3 - SPECT-CT FUSED images corresponds to D12 left costovertebral joint ( figure 3).
A fluoroscopy guided D12 left costovertebral joint corticosteroid injection was performed and subsequently patient becomes pain free since then (more than two years).
The increased 99mTc MDP activity at the costovertebral joint on SPECT-CT is highly predictive of pain or positive response to percutaneous injection. Patients may have corresponding thoracic back pain, with increasing use of combined imaging such as SPECT-CT, specific localization of activity to these articulations may become more common. Therefore, it is important to report these findings to help establish the prevalence and significance of 99mTc MDP activity at these joints.
99mTc MDP SPECT is often performed for the purpose of identifying the cause of back pain, but its utility in degenerative conditions remains unclear. Previous reports addressing the significance of SPECT-CT activity in the costovertebral and costotransverse joints are limited, but studies have been performed to evaluate the significance of radiotracer activity in facet joints. Prior studies suggest that injection of facet joints with increased 99mTc MDP activity results in clinical improvement. Degenerative changes of the costovertebral joints are present in approximately half of all people on postmortem examination. They may be asymptomatic in most instances, but there are numerous reports of both localized pain and referred patterns such as chest pain . Indeed, pain reduction with administration of local anesthetic and corticosteroid as a criterion to direct resection arthroplasty of these joints has been reported. Additionally, pain related to these joints reportedly can be present in the absence of anatomic degenerative changes. Identification of both an imaging marker of this pain and effective minimally invasive treatment is desirable. Physiologic imaging markers such as 99mTc MDP are attractive prospects because they may identify joints with inflammation, and presumably associated pain, that could in principle be ameliorated with local anti-inflammatory medication.
In conclusion, our results indicate that 99mTc MDP activity at the costovertebral and costotransverse joints on SPECT-CT is highly predictive of corresponding thoracic back pain or positive response to percutaneous injection. Patients may have corresponding thoracic back pain, but more than half did not. When corresponding thoracic back pain was present, there was often relief with percutaneous injection. Given the retrospective design and small number of patients in the study, future prospective investigation with a larger number of patients is necessary to further define the significance of costovertebral and costotransverse joint 99mTc MDP activity on SPECT-CT.