What does decreased bone marrow signal mean?
Diffuse T1 vertebral bone marrow signal loss is associated with replacement of fatty marrow by edema or cellular tissue. T1-weighted imaging without fat suppression is one of the most important sequences for distinguishing between normal and abnormal bone marrow.
What is the clivus in the brain?
General. The clivus (Latin for “slope”) forms the central skull base. It is formed by the synostosis of the basisphenoid (sphenoid bone) and basiocciput (occipital bone). During early development, the axial sclerotomes of the first somites are integrated into the skull base to form the basioccipital part of the clivus.
What is the function of clivus?
The clivus is an important landmark for checking for anatomical atlanto-occipital alignment; the clivus, when viewed on a lateral C-spine X-ray, forms a line which, if extended, is known as Wackenheim’s clivus line. Wackenheim’s clivus line should pass through the dens of the axis or be tangential to it.
Is the clivus of normal marrow always abnormal?
A clivus of very low signal intensity (signal void) on T1-or T2-weighted images was always abnormal. The clivus with marrow reconversion was uniformly hypointense relative to the pons on T1-weighted images and isointense relative to normal marrow on T2-weighted images.
Can a normal Clivus be detected on a MR image?
Thus, clinically suspected or unsuspected disease of the clivus may be detected on the routine cranial MR image. This prompted us to review the MR signal intensity of the clivus in both normal adults and those with disease. MR features that differentiate the two groups are discussed. Materials and Methods
Is the Clivus with marrow reconversion uniformly hypointense?
The clivus with marrow reconversion was uniformly hypointense relative to the pons on T1-weighted images and isointense relative to normal marrow on T2-weighted images. The intensity patterns of the normal clivus on T1-and T2-weighted MR images change predictably with advancing age.
How is the Clivus similar to subcutaneous fat?
Knowledge of these changes allows the diagnosis of the abnormal clivus . Kimura et al 1 divided the appearance into three grades, by comparing the clivus to the pons and subcutaneous fat. A high signal was similar to subcutaneous fat, whereas low was iso- to slightly hypointense to the pons.
A clivus of very low signal intensity (signal void) on T1-or T2-weighted images was always abnormal. The clivus with marrow reconversion was uniformly hypointense relative to the pons on T1-weighted images and isointense relative to normal marrow on T2-weighted images.
Where does the Clivus appear on a CT scan?
A normal clivus appears on the CT-scan as a central portion of cancelllous bone with marrow bone elements, bounded by peripheral compact cortical bone. On the normal MRI, the signal intensity depends on the nature of the marrow in the cancellous bone.
The clivus with marrow reconversion was uniformly hypointense relative to the pons on T1-weighted images and isointense relative to normal marrow on T2-weighted images. The intensity patterns of the normal clivus on T1-and T2-weighted MR images change predictably with advancing age.
Knowledge of these changes allows the diagnosis of the abnormal clivus . Kimura et al 1 divided the appearance into three grades, by comparing the clivus to the pons and subcutaneous fat. A high signal was similar to subcutaneous fat, whereas low was iso- to slightly hypointense to the pons.