Application Of CT And MRI In The Diagnosis Of Cavernous Sinus Region Diseases

Purpose: The cavernous sinus (CS) is tiny and complex. There are kinds ofdiseases that could all oppress or invade adjacent cranial nerves and bloodvessels. All of them would cause CS syndrome, such as ophthalmoplegia,conjunctival edema, exophthalmos, Horner syndrome, trigeminal nerve sensoryloss, etc. While different causes of CS syndrome has different therapeuticregimens. Imaging examination plays a very important role in early detectionand early treatment of lethal critical diseases such as cavernous sinus thrombosis(CST). Meanwhile, they could help us generally judge the nature of lesions.What’s more, it can observe the anatomical relationship between lesions andtheir adjacent structures as well, which will contribute to the surgical operationapproaches and reduce the long-term sepuelae. This article retrospective analysisthe imaging findings of CS lesions for107cases (130lesions) that are clinicaland pathological diagnosed, summarize the basic imaging findings and discussthe diagnostic value of cavities of CS and changes of MC cavity for the originand nature of diseases.Method: There is a collection of107cases of CS diseases (130lesions)from our hospital between May,2010and December,2012.Fifty male cases andfifty-seven female cases included, ages between20and79,the average is49.Eleven primary tumors(neurilemmoma for6,meningiomafor4,ganglioglioma for1),sixty secondary or invasive tumors(invasive pituitary adenoma for45,chordoma6,cholesteatoma3,maturecysticteratoma1,nasopharyngeal arcinoma1,brain metastasis of adenoid cystic carcinoma for1,breast cancer metastasis for1, lung cancer metastasis for1,inverted papilloma cancerization for1),twenty-eight vascular lesions(hemangioma for12,aneurysm for8,duralcavernous fistula for3,traumatic carotid cavernous fistula for5),and eightthrombophlebitis. One cavernous sinus hypoplasia has not been containedbecause of its small number of cases. Of all cases, CT scannings are for4,MRIplain scannings are for98,enhanced MRI scannings are for88, MRI plain andenhanced scannings are for82,MRA scannings are for2,and SE-EPI DWIscannings are for24.Cavernous sinus inflammation is confirmed by clinicaltreatment, vascular lesions are confirmed by DSA, one breast metastasis,onelung metastasis, others are confirmed by pathology.Results: Of all CS diseases, Neoplastic lesions has the percentage of66.4,of which secondary tumors has the percentage of56.1,primary tumors10.3,vascular lesions26.2, and inflammatory lesions7.5. There are statisticaldifferences in the constituent ratio of different CS lesions respectively(univariate Chi-Square Test, χ~2=37.5，P<0.05). There are no statisticaldifferences in the category of different CS lesions respectively(χ~2=7.77，P>0.05). There are statistical differences in the age group and side classificationof different CS lesions (Fisher’s exact test, P=0.01<0.05). Imaging findings:①All CS of the lesion sides expand with abnormal density/signal and lateral wall bulge can be seen except one CS dysplasia.②117ICA get involved, whichhas the percentage of90.③Abnormal flowing void signals can be seen in allvascular lesions on MRI.④Of all98MRI plain scannings, the lesions mainly inintermediate signal intensity has the percentage of72.5,mainly inhypointensity on T1WI and hyperintensity on T2WI27.6.There are statisticaldifferences in the overall signal composition of different CS lesions.(Fisher ’sexact test, P=0<0.05).Vascular lesions group are mainly exhibited hypointensityon T1WI and hyperintensity on T2WI(P<0.05), the other three groups aremainly exhibited intermediate signal intensity(P <0.05).⑤Of all107MRIscannings or CTA, light to moderate enhancement has the percentage of50.5,obvious enhancement43.9and no enhancement5.6.There are statisticaldifferences in the enhancement types of different CS lesions(Fisher ’s exact test,P <0.01).To compare the four groups respectively, secondary tumors mainlyenhance lightly to moderately, the other three all mainly enhance obviously(P=0<0.05).⑥Meckel cavity that gets involved has the percentage of55.1%,ofwhich cerebrospinal fluid signal disappears counts25.2%,partial remainingcounts18.7%.Both MC cavity expands and has abnormal signals counts11.2%.Six MC cavities of neurilemmoma cases expand and has abnormalsignals. There are statistical differences on different CS lesions with MC cavitychange（sFisher ’s exact test，P <0.05）.The primary tumors group has the highestpercentage in CS cavity invaded(90.9%),then are the vascular lesiongroup(51.6%) and the thrombophlebitis group(50.0%), the secondary group has the lowest(P=0.006<0.05).⑦The incidence of CS cavity invaded: the most arethe inside and outside cavity, then is the rear upwards, and the front downwardsis the least. The constitute of CS lesions: secondary tumors are common, thenare vascular lesions, primary tumors andthrombophlebitis are rare.Differentdiseases invade different cavities: primary tumors are apt to invade outsidecavity, then are the rear upwards and the front downwards, the inside are theleast. Secondary tumors are apt to invade the rear upwards and the inside, then isthe outside, the least is the front downwards. The invasive pituitary adenoma allinvades the inside cavity. Vascular lesions are apt to invade the outside cavity,then are the inside and the front downwards, the least is the rear upwards. Fistulaof artery invades the whole cavity. Thrombophlebitis apt to invade the outside,then is the front downwards, the inside and the rear upwards are rare（χ~2=24.89，P <0.05）.Conclusion:①Secondary tumors accounts for the majority part of CSlesions.②There is no statistical difference in gender constitution of CSlesions.③The common attacks of CS lesions are unilateral. There are statisticaldifferences in side classification and age constitution of CS lesions.④Thetransverse diameter of CS expands, lateral wall bulges, density/signal changes,and ICA surrounds, narrows or partial expand suggest that the CS lesionsexist.⑤Abnormal flowing void signals indicate vascular lesions.⑥Neoplasticlesions and thrombophlebitis are mainly exhibited intermediate signalintensity.⑦Light to moderate enhancement are common in secondary tumors. Obvious enhancement are common in vascular lesions and thrombophlebitis.⑧The changes of CS cavity and MC cavity contributes to judge the origin andproperties of lesions.