MR imaging of the normal and abnormal clivus

Area of Science:

• Radiology
• Neuroimaging
• Oncologic Imaging

Background:

• The clivus, a key midline structure at the skull base, exhibits complex anatomy and is susceptible to pathology.
• Accurate characterization of clival abnormalities on magnetic resonance imaging (MRI) is crucial for diagnosis and treatment planning.

Purpose of the Study:

• To define the typical magnetic resonance imaging (MRI) appearance of the normal adult clivus.
• To identify distinguishing MR features of abnormal clival conditions, specifically tumor invasion and marrow reconversion, compared to normal anatomy.

Main Methods:

• Retrospective review of 330 T1-weighted sagittal, 80 T2-weighted sagittal, and 83 gadopentetate-dimeglumine-enhanced MR scans of normal adults.
• Comparison with MR images from 21 patients with pathologically confirmed abnormal clivi (19 tumors, 2 marrow reconversions).

Main Results:

• Normal adult clivus shows mixed low and high signal intensity on T1-weighted images, with low-intensity portions isointense/hyperintense to the pons and bright foci.
• Pathologic clivi (tumors) typically exhibit hypointense signal relative to the pons on T1-weighted images, lacking bright foci.
• On T2-weighted images, normal clivus is isointense to the pons; tumors are often hyperintense, but can be isointense and undetectable.
• Normal clivus shows some enhancement; tumors enhance intensely. Signal void on T1/T2 is abnormal. Marrow reconversion is uniformly hypointense on T1.

Conclusions:

• Specific signal intensity patterns on T1- and T2-weighted MRI, along with enhancement characteristics, differentiate normal adult clivi from tumors and marrow reconversion.
• MRI is effective in characterizing clival pathologies based on signal intensity and enhancement patterns.