Whole-Body SPECTCT versus Planar Bone Scan with Targeted SPECTCT for Metastatic Workup

Abstract EN

Purpose.

The use of SPECT/CT in bone scans has been widespread in recent years, but there are no specific guidelines concerning the optimal acquisition protocol.

Two strategies have been proposed: targeted SPECT/CT for equivocal lesions detected on planar images or systematic whole-body SPECT/CT.

Our aim was to compare the diagnostic accuracy of the two approaches.

Methods.

212 consecutive patients with a history of cancer were referred for bone scans to detect bone metastases.

Two experienced readers randomly evaluated for each patient either planar images with one-field SPECT/CT targeted on equivocal focal uptakes (targeted SPECT/CT) or a whole-body (two-field) SPECT/CT acquisition from the base of the skull to the proximal femurs (whole-body SPECT/CT).

The exams were categorized as “nonmetastatic,” “equivocal,” or “metastatic” on both protocols.

The presence or absence of any extra-axial skeletal lesions was also assessed.

The sensitivity and specificity of both strategies were measured using the results of subsequent imaging follow-up as the reference standard.

Results.

Whole-body SPECT/CT had a significantly higher sensitivity than targeted SPECT/CT to detect bone metastases (p=0.0297) and to detect extra-axial metastases (p=0.0266).

There was no significant difference in specificity among the two approaches.

Conclusion.

Whole-body SPECT/CT is the optimal modality of choice for metastatic workup, including detection of extra-axial lesions, with improved sensitivity and similar specificity compared to targeted SPECT/CT.