Imaging Guidelines for Superior Semicircular Canal Dehiscence

Imaging Modality

• The American College of Radiology (ACR) states that high‑resolution, non‑contrast temporal‑bone CT with multiplanar reconstruction aligned to the superior semicircular canal is the definitive imaging test for confirming superior canal dehiscence. 1

Reconstruction Techniques

• The ACR recommends performing dedicated Pöschl‑plane (parallel to the superior canal) and Stenvers‑plane (perpendicular to the superior canal) reconstructions to reliably visualize bony dehiscence and to estimate its size. 2

• These specialized reconstructions improve detection of the dehiscence compared with standard axial/coronal CT views. 3

Use of Intravenous Contrast

• The ACR advises that intravenous contrast does not add diagnostic value for temporal‑bone evaluation of superior canal dehiscence and should be omitted. 2

Alternative Imaging Modalities

• The ACR cautions that standard head CT lacks the spatial resolution needed for inner‑ear structures and therefore has a low diagnostic yield for superior canal dehiscence. 4

• The ACR also notes that MRI is insufficient as a first‑line study for SCDS because it cannot delineate the fine bony anatomy required for diagnosis. 2

American College of Radiology Recommendations for Imaging and Clinical Diagnosis of Superior Semicircular Canal Dehiscence

Imaging Guidelines

• High‑resolution, non‑contrast temporal bone CT with multiplanar reconstruction (Pöschl and Stenvers planes) is endorsed by the American College of Radiology as the definitive imaging test for confirming superior semicircular canal dehiscence, provided that clinical suspicion based on characteristic symptoms is already present. 5

Clinical Diagnostic Criteria

• The American College of Radiology specifies that the initial diagnostic work‑up should focus on characteristic symptoms such as sound‑induced vertigo/oscillopsia (Tullio phenomenon), pressure‑induced vertigo (Hennebert’s sign), autophony, and a conductive‑type hearing loss with an intact tympanic membrane. 5

Imaging Requirements for Superior Semicircular Canal Dehiscence Diagnosis

Definitive Imaging Modality

• The American College of Radiology states that high‑resolution temporal bone CT with sub‑millimeter collimation and multiplanar reconstruction in both the Pöschl plane (parallel to the superior semicircular canal) and the Stenvers plane (perpendicular to the superior semicircular canal) is the definitive test for confirming or excluding superior semicircular canal dehiscence. 6

Diagnostic Accuracy Compared with Standard Views

• The American College of Radiology reports that standard axial and coronal temporal bone CT views have significantly lower diagnostic accuracy for detecting SSCD than dedicated canal‑plane reconstructions. 6

Recommendation When Initial Scan Is Inadequate

• If clinical suspicion for SSCD persists after a non‑dedicated CT report, the American College of Radiology recommends repeating the temporal bone CT with dedicated Pöschl and Stenvers plane reconstructions. 6