Related Experiment Videos
Diagnosis of ruptured intracranial dermoid cyst: value MR over CT
A S Smith1, J E Benson, S I Blaser
1Department of Radiology, Unviersity Hospitals of Cleveland, OH 44106.
Abstract:
The CT and MR findings of seven patients with pathologically proved ruptured dermoid cysts were reviewed to analyze the MR characteristics and to see if MR evaluation had significant advantages over CT. In six cases, both CT and MR identified fatty material in the CSF spaces. Hemorrhage complicated preoperative diagnosis in one case. Patterns of extraaxial fat distribution were as follows: intraventricular fat/CSF levels (three patients), generalized subarachnoid spread (six patients), and localized subarachnoid spread with sulcal widening (one patient). There was no correlation between fat distribution and clinical symptoms. MR showed the vascular involvement better than CT did in five of seven cases, and showed extension of the cysts into the skull base in two cases. Signal intensity of the solid mass was low on T1-weighted MR images and inhomogeneously high on T2-weighted images, which correlated pathologically with the presence of crystal cholesterol, hair, sebaceous glands, and epithelial cells in all cases. On MR, brain parenchyma showed little edema or other reaction to the masses, which were typically large. The value of MR over CT in the examination of ruptured dermoid cysts is the conspicuity of the extent of subarachnoid spread, involvement of the extraaxial structures, and evidence of vascular compromise, which can obviate angiography. MR had no advantage over CT in making the initial diagnosis of ruptured dermoid, but it would be the preferred preoperative study.
Insights
Magnetic resonance imaging (MRI) offers advantages over computed tomography (CT) for evaluating ruptured dermoid cysts, particularly in assessing spread and vascular compromise, making it the preferred preoperative study.
Area of Science:
- Radiology
- Neurology
- Pathology
Background:
- Ruptured dermoid cysts are rare intracranial lesions.
- Accurate preoperative assessment is crucial for surgical planning.
Purpose of the Study:
- To analyze the magnetic resonance (MR) characteristics of ruptured dermoid cysts.
- To compare the diagnostic advantages of MR imaging over computed tomography (CT).
Main Methods:
- Retrospective review of CT and MR findings in seven patients with pathologically proven ruptured dermoid cysts.
- Analysis of fat distribution, signal intensity, and extraaxial spread on MR and CT.
Main Results:
- Both CT and MR identified fatty material in cerebrospinal fluid (CSF) spaces in most cases.
- MR demonstrated vascular involvement and skull base extension better than CT.
- MR signal intensities correlated with cyst contents (cholesterol, hair, etc.).
- MR showed less brain parenchyma reaction compared to CT.
Conclusions:
- MR imaging is superior to CT for evaluating the extent of subarachnoid spread and vascular compromise in ruptured dermoid cysts.
- MR can obviate the need for angiography in some cases.
- While CT can make the initial diagnosis, MR is the preferred preoperative study.