Optimizing modality selection for image-guided procedures: an analysis of the challenges to ultrasound guidance.
Selection of the most appropriate modality for image guidance is essential for procedural success. We identified specific factors contributing to failure of ultrasound-guided procedures that were subsequently performed using CT guidance.



This single-center, retrospective study included 164 patients who underwent a CT-guided biopsy, aspiration/drainage, or ablation after initially having the same procedure attempted unsuccessfully with ultrasound guidance. Review of the procedure images, reports, biopsy results, and clinical follow-up was performed and the reasons for inability to perform the procedure with ultrasound guidance were recorded. Patient cross-sectional area and depth to target were calculated. Differences in area and depth were compared using general linear modeling. Depth as a predictor of an unfavorable body habitus designation was modeled using logistic regression.



US guidance was successful in the vast majority of cases (97%). Of the 164 procedures, there were 92 (56%) biopsies, 63 (38%) aspirations/drainages, and 9 (5%) ablations. The most common reason for procedure failure was poor acoustic window (83/164, 51%). Other reasons included target lesion being poorly discerned from adjacent tissue (61/164, 37%), adjacent bowel gas (34/164, 21%), body habitus (27/164, 16%), and gas-containing collection (22/164, 13%). Within the biopsy subgroup, patients for whom body habitus was a limiting factor were found to have on average a larger cross-sectional area and lesion depth relative to patients whose body habitus was not a complicating factor (p < 0.0001 and p = 0.0009).



Poor acoustic window was the most common reason for procedural failure with ultrasound guidance. In addition, as lesion depth increased, the odds that body habitus would limit the procedure also increased. If preliminary imaging suggests a limited sonographic window, particularly for deeper lesions, proceeding directly to CT guidance should be considered.
Department of Diagnostic Imaging, Rhode Island Hospital, 593 Eddy Street, Providence, RI, 02903, USA. mbeland@lifespan.org.
Michael D
MD
Beland
Department of Diagnostic Imaging, Rhode Island Hospital, 593 Eddy Street, Providence, RI, 02903, USA.
Laura A
LA
Sternick
Department of Biostatistics, Rhode Island Hospital, 593 Eddy Street, Providence, RI, 02903, USA.
Grayson L
GL
Baird
Department of Diagnostic Imaging, Rhode Island Hospital, 593 Eddy Street, Providence, RI, 02903, USA.
Damian E
DE
Dupuy
Department of Diagnostic Imaging, Rhode Island Hospital, 593 Eddy Street, Providence, RI, 02903, USA.
John J
JJ
Cronan
Department of Radiology, Brigham and Women's Hospital, Bc-3-010c.11, 1620 Tremont St, Boston, MA, 02120, USA.
William W
WW
Mayo-Smith
D055011:Ablation Techniques; D000328:Adult; D000368:Aged; D003287:Contrast Media; D003657:Decision Making; D004322:Drainage; D005260:Female; D006801:Humans; D061705:Image-Guided Biopsy; D008297:Male; D008875:Middle Aged; D015641:Radiography, Interventional; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional
D003287:Contrast Media