Is there Still Enough Diagnostic Confidence with Bone Spect Scintigraphy Alone: A Retrospective Evaluation and Extended Review of the Literature

ABSTRACT

Aim: Single photon emission computed tomography (SPECT) dramatically increases the sensitivity of bone scanning for detection of spinal abnormalities. However, the level of specificity obtained by SPECT remains controversial and increased diagnostic confidence can be obtained with new imaging modalities such as fused PET/CT and SPECT/CT. Patients and Methods: Between 7/2005 and 7/2007 ninety one patients with different malignant primary tumors were investigated. Following injection of 555 MBq 99mTc – MDP planar and SPECT images were performed in all patients. Results: Out of a total of 145 spinal lesions was confirmed by radiography, SPECT detected 133 (91%). In contrast, planar scintigraphy detected only 99/145 (68%) lesions. SPECT uptake pattern including the vertebral body and an adjacent pedicle was seen in 9/28 (32%) of metastatic lesions and in 1/2 (50%) cases of spondylitis. SPECT uptake pattern including the pedicle alone was seen in 45/115 (39%) of degenerative alterations. Focal lesions limited to the lateral part of the vertebral body, especially to the pars interarticularis (n=8), facet joints (n=14) and costotransversal joints (n=6), were correctly diagnosed as spondylarthrosis and costotransversalarthrosis in all cases. Furthermore, SPECT uptake pattern of spondylitis was biconcave, whereas metastatic lesions showed focal or linear uptakes. Conclusion: SPECT without image fusion still gives sufficient diagnostic confidence for the differentiation of benign and malignant spine lesions. Uptake patterns localized at the facet joints or localized at the pedicles are indicative for benign lesions, whereas continuous uptake patterns of the vertebral body and adjacent pedicle remain suspicious for malignancy.

Keywords: