Radiological approach to basilar invagination type B: Reliability and accuracy

Area of Science:

• Radiology
• Neurosurgery
• Orthopedics

Background:

• Basilar invagination (BI) is a complex craniovertebral junction abnormality.
• Accurate diagnosis of BI is crucial for appropriate management and patient outcomes.
• Radiological assessment plays a key role in diagnosing BI, but the reliability of various imaging metrics needs evaluation.

Purpose of the Study:

• To evaluate the inter-rater reliability and diagnostic accuracy of different radiological measurements for basilar invagination (BI).
• To compare the reliability of distance from odontoid apex to Chamberlain's line (OA-CL) and other angles (Boogard's angle - BoA, clivo-axial angle - CXA, clivo-dens angle - CDA, clivo-palate angle - CPA).

Main Methods:

• Retrospective study including 42 BI cases and 79 controls with CT and MR imaging.
• Three radiologists assessed OA-CL, BoA, CXA, CDA, and CPA on midsagittal CT and MR images.
• Intraclass correlation coefficient (ICC), t-test, and ROC curve analysis were used to determine reliability and accuracy.

Main Results:

• OA-CL and BoA demonstrated excellent inter-rater agreement (ICC > 0.88) on both CT and MR.
• BoA showed high diagnostic accuracy (0.954) with an area under the ROC curve of 0.977.
• CXA and CDA had moderate reliability and diagnostic accuracy, while CPA was found to be inadequate.

Conclusions:

• OA-CL and BoA are highly reliable radiological measurements for diagnosing basilar invagination (BI).
• CXA and CDA can be used as complementary diagnostic tools.
• CPA is not recommended for the diagnosis of BI due to its inadequacy.