Angiography Of Superficial Cerebral Veins With The 64 Detector Row Helical CT

Objectives To explore the normal computed tomgraphic venography (CTV) features of superficial cerebral veins (SVs) by observing different gender and age groups, for the occurrence of cerebral venous thrombosis (CVT) in vivo mechanism to provide a new interpretation. To further improve the morphological materials of arachnoid granulations (AGs) by micro-dissection, histology and CT, we observed with AGs at the entrance of the SVs drain into dural sinus. It provides a basis for CVT of imaging differential diagnoses. To explore the normal CTV features of the superficial anastomotic veins, it provides the basis for diagnosis of vacular disease and selection of related surgical approach.Methods①110 patients (59 male, 51 female; age range, 10-78yr; mean age, 41yr) who underwent CTV without cerebral venous diseases were obtained to investigate the superficial cerebral veins. The SVs were divided into three groups: superior saggital group, tranverse sinus group, and middle cranial fossa group.②Forty patients who had both normal conventional brain CT and CTV were retrospectively analyzed. The morphological characteristics and distribution of AGs at the entrance of the SVs drain into dural sinus are observed. Thirty-three adult cadaveric heads were used for microsurgical dissection; Histological sections of AG specimens from 3 cadaver heads were examined.③110 cases of adult head CTV, the cerebral superficial anastomotic veins were reconstructed by the application of multi-planar reconstruction (MPR), volume rendering (VR) and maximum intensity projection (MIP).Results 1. Superior sagittal sinus group①The anterior segmental SVs draining into superior sagittal sinus (SSS) was a total of 261. The SVs (23.4%, 61/261) drained into the SSS at an acute angle (10°～65°) against the blood flow in the sinus, 42.5% (111/261) entered the SSS at right angles (66°～105°), and 34.1% (89/261) entered the SSS at an obtuse angle (106°～170°) in the usual direction of blood flow within the sinus. The SVs'angle of female group was significantly less than male. There is statistical significance in SVs'angle of 20-29 age groups between female and male. The transverse diameter (TD) of SV was (2.6±0.8) mm, vertical dimater (VD) was (1.9±0.5) mm and cross-sectional area (CSA) was (5.2±2.9) mm2. There is statistical significance in SVs'diameter and CSA of 20-29 age groups between female and male.②The posterior segmental SV draining into superior sagittal sinus (SSS) was a total of 698. The SVs (65.0%, 454/698) drained into the SSS at an acute angle against the blood flow in the sinus, 26.4% (184/698) entered the SSS at right angles, and 8.6% (60/698) entered the SSS at an obtuse angle in the usual direction of blood flow within the sinus. The SVs'angle of female group was significantly less than male. The TD of SV was (3.5±1.2) mm, VD was (2.6±0.7) mm and CSA was (9.0±4.6) mm2. The diameter and CSA of SVs among multiple age-groups were significant difference. The SVs'diameter and CSA of female group was significantly less than maleb between 40～49 and≥60 age groups.③AGs at the enterance of SVs: They mainly focused on the S3 and venous lacunae. Little AGs scattered in the S1. In CTV image, AGs appeared as hypodense and oval-shaped filling defects in SSS.④The anastomosis of SVs: A total of 3 type's anastomosis of SVs was Trolard vein involvement.Ⅰtype, anastomosis of cerebral superior and middle veins, 34% (37/110);Ⅱtype, anastomosis of cerebral superior, middle and inferior veins, 49% (54/110);Ⅲtype, anastomosis of cerebral superior veins, 33% (36/110). In the unilateral cerebral hemisphere, the majority of superficial venous anastomosis shows 1-3 types. More than 3 types of venous anastomosis were less than showed. In addition, seven (8%) on both sides of the brain hemispheres was not found in any type of superficial venous anastomosis. 2. Transverse sinus group,①the SVs draining into transverse sinus (TS) was a total of 361. The SVs (30.2%, 109/361) drained into the TS at an acute angle against the blood flow in the sinus, 50.1% (181/361) entered the TS at right angles, and 19.7% (71/361) entered the TS at an obtuse angle in the usual direction of blood flow within the sinus. There was statistical significance in angle of SVs between male and female. The TD of SV was (2.7±0.7) mm, VD was (2.1±0.5) mm and CSA was (5.7±2.9) mm2. The SVs'diameter and CSA of female group was significantly less than male. In addition, six on both sides of the brain hemispheres was not found into intrasverse sinus of SVs.②AGs at the enterance of SVs: CTV images showed that AGs appeared as isodense or hypodense defects at the enterance of SVs entering into TS. The density was the same to that of cerebrospinal fluid. Some or all AGs were surrounded by contrast medium.③The anastomosis of SVs: A total of 3 type's anastomosis of SVs was Labbe vein involvement.Ⅰtype, anastomosis of cerebral middle and inferior veins, 43% (47/110);Ⅱtype, anastomosis of cerebral superior and inferior veins, 9% (10/110);Ⅲtype, anastomosis of cerebral superior, middle and inferior veins, 54% (49/110). 3. Middle cranial fossa group,①the superficial middle cerebral vein (SMCV) draining into transverse sinus (TS) were a total of 185. All SVs entered the cavernous sinus (CS) at an obtuse angle in the usual direction of blood flow within the sinus. The TD of SMCV was (2.9±0.6) mm, VD was (2.5±0.5) mm and CSA was (6.9±2.7) mm2. The diameter of SVs between male and female groups was significant difference in 30～39, 40～49, 50～59 age groups.②In middle cranial fossa the AGs occured in the following situations in order of frequency: The middle meningeal sinus, sphenoparietal sinus, lateral foramen rotundum and cavernous sinus. AGs usually showed round, oval-shaped and irregular-shaped. AGs could be divided into individual type and leaflet type under light microscope. The number of AGs observed by microanatomy and CTV was 6.9 and 2.0 respectively. The AGs of cavernous sinus was not localized precisely on CTV.③The anastomosis of SVs: A total of 4 type's anastomosis of SVs was Labbe vein involvement. Except that anastomosis of cerebral superior and middle veins, anastomosis of cerebral superior, middle and inferior veins and anastomosis of middle and inferior veins, anastomosis of Sylvian veins only accounted for 3% (3/110).Conclusion①The SVs'diameter, CSA and angle are existed differences between age and gender: the SSS group of SVs'diameter, CSA and angle of female group are smaller than male. The SVs'angle of S1 segment in 20-29 age groups is less than other age groups. The TS group of SVs'diameter and CSA of female group are smaller than male. The SVs differences between gender and age may be the occurrence of cerebral venous thrombosis with gender and age differences in the morphological basis.②There is a lot of AGs in the middle cranial fossa, mainly in the middle meningeal sinus, sphenoparietal sinus, lateral foramen rotundum and cavernous sinus. CT can show the distribution of AGs. AGs at the entrance of SVs drain into SSS and TS are the cause of dural entrance of SVs not located precisely in CTV. It provides a basis for cerebral venous thrombosis of imaging differential diagnoses.③The cerebral superficial anastomotic veins types are diverse and relatively large individual differences. 64 detector rows helical CT is an individual, multi-angle, integrated, rapid noninvasive method to depict the cerebral superficial anastomotic veins. It is helpful for the early diagnosis of venous disease and selection of related surgical approach.