Improvement of diagnostic confidence with SPECT-CT in routine clinical practice: A 6 month audit

Learning Objectives Obtain knowledge on the additional value of SPECT-CT imaging in clinical practice.

Summary: 107 SPECT-CT's were performed over 6 months (47 Bone, 14 Iodine, 11 Gallium, 9 Parathyroid, 6 Octreotide, 5 hepatobiliary, 5 Sulfur Colloid, 4 Red Cell Haemangioma, 3 Renal, 1 Red Cell GI Bleed, 1 MIBG, 1 White Cell). Planar and SPECT scans were reviewed by non-blinded nuclear medicine physicians and areas of uptake deemed non-physiologic classified according to a) anatomic localisation and b) likely diagnosis according to a 3 point confidence scale (1= equivocal, 2 = probable, 3 = definite). This was followed by separate review using fused SPECT/CT imaging and a similar confidence scale. With regard to anatomic localisation, 197 foci of non-physiologic uptake were seen on planar and SPECT scintigraphy. 83 probable foci [42%] and 13 equivocal foci [7%] were improved in localisation confidence to definite. 47 foci [ 24%] changed in location following SPECT-CT. SPECT-CT improved confidence in confirming the probable diagnosis in 33 [31%] of patients, with the diagnosis being changed in 7 patients [7%]. 10 [6%] equivocal foci of uptake on planar/SPECT imaging were confirmed on SPECT-CT as physiologic. Review of SPECT-CT imaging improved anatomic localisation in 73% of all foci. SPECT-CT changed diagnosis or improved diagnostic confidence in 38% of all patients. SPECT-CT appears to improve both sensitivity, by allowing more precise anatomic localisation, and specificity, by characterising correlatory anatomic pathological change.