Magnetic resonance imaging and diffusion-weighted images of cystic meningioma: correlating with histopathology.
OBJECTIVE
Cystic meningiomas are quite rare, accounting for between 2% and 4% of all intracranial meningiomas. To better understand all the types of cystic meningiomas with magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI) and histopathology, we attempted to correlate the MRI and DWI features of cystic meningiomas with the histopathological findings.


METHODS
We collected 15 cases of cystic meningiomas diagnosed between 1993 and 2000 (5 men and 10 women, 41-80 years old). Fifteen patients had conventional MRI and 14 patients had CT scan. DWI was also performed in three patients. Apparent diffusion coefficient (ADC) images were also done. In the classification of cystic meningiomas, we adopted Worthington's classification, which divides cystic meningiomas into five groups.


RESULTS
Tumor resection was performed in all patients. Tumor locations were as follows: convexity (10), falx (2), pterion (2) and lateral ventricle (1). Regarding the types of cystic lesion, type I (3), type II (3), type III (3), type IV (1) and type V (5) were found. Histopathologically, there were six atypical, four meningothelial, two malignant, one fibroblastic, one angiomatous and one transitional. Intratumoral cystic meningiomas were more common in atypical types. Peritumoral cystic meningiomas were more common in meningothelial and atypical types. The cystic portion of the three cystic meningiomas was hypointense or mildly hyperintense on DWI. ADC ratio (ADCR) of DWI for cyst part of two type I cystic meningiomas was 1.25 and 0.82; for cyst part of one type III was 4.04.


CONCLUSIONS
It is important to recognize the neuroimaging features of the cystic meningiomas. Conventional MRI and DWI may play an important role in the preoperative radiological evaluation and the recognition of these types of cysts for proper surgical treatment.
Chen
Tai-Youeng
TY
Department of Radiology, Veterans General Hospital-Kaohsiung, National Yang Ming University, National Defense Medical Center, 386 Ta-Chung First Rd., Kaohsiung 813, Taiwan, ROC.
Lai
Ping-Hong
PH
Ho
Jih-Tsun
JT
Wang
Jyh-Seng
JS
Chen
Wei-Liang
WL
Pan
Huay-Ben
HB
Wu
Ming-Ting
MT
Chen
Clement
C
Liang
Huei-Lung
HL
Yang
Chien-Fang
CF
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media / Q000008:administration & dosage; D003560:Cysts / Q000145:classification / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008577:Meningeal Neoplasms / Q000473:pathology*; D008579:Meningioma / Q000473:pathology*; D008875:Middle Aged; D009367:Neoplasm Staging; D013223:Statistics as Topic; D014057:Tomography, X-Ray Computed
D003287:Contrast Media; D019786:Gadolinium DTPA