Application Of CT Venography In The Diagnosis And Treatment Of Intracranial Diseases

Part I The study of the technique of CT venography inheadObjective To investigate the optimal delay time and slice thickness of CTV in the head. To evaluate the demonstration rate of cranial vein on CTV, and compare it with MRV and DSA. The use of CT and MR image fusion technique was also explored. Materials and Methods CT scanning was performed with a GE sixteen-slice spiral unit. 1. The plane dynamic test scanning at nuclei basales level was performed with contrast material 1.5 ml/kg at a flow rate of 3.0 ml/s of 41 volunteers. A time - density curve of the internal cerebral vein and superior sagittal sinus was got at the workstation. 2. The data obtained by the optimal delay time with scanning thickness of 1.25 mm were retrospectively reconstructed with slice thickness of 0.625 mm and 1.25 mm respectively. Three-dimensional CTV was reconstructed with VR to investigate the optimal reconstructed slice thickness. Statistical significance was determined with the t test (α=0.05). 3. To investigate the demonstration rate of cranial vein with CTV technique 50 volunteers underwent CTV imaging. The demonstration of cranial venous system (including superficial cerebral group, deep cerebral vein and cranial sinuses) was rated. The demonstration rate of the CTV was compared with MRV and DSA. Results 1 .The optimal delay time of CTV in the head is 36 s and the optimal reconstructed slice thickness is 0.625 mm(P <0.05). The veins can be well revealed with delay time of 36 s. 2.The quality of images of slice thickness of 0.625 mm is superior to the quality of slice thickness of 1.25 mm. The reconstruction of 0.625 mm can reveal more small vasculars and reduce the step-like artifact. 3. The demonstration rate is 100 percent of superior sagittal sinus, rectus sinus, transverse sinus, sigmoid sinus, as well as great vein of Galen, superior cerebral vein, middle cerebral vein, 92% of inferior sagittal sinus, basilar vein, thalamostrizte vein, cavernous sinus, superior petrosal sinus and Labbe vein, 78-84% of terminal vein, septal vein, superior vermian vein, 65% of inferior petrosal sinus. The quality of the small veins on CTV is better than on MRV. Conclusion A satisfactory CTV in the head can be got with optimal delay time and reconstructedparameters. The quality of the small veins on CTV is better than MRV. Part II CT venography appearance of normal cranialvenous systemObjective To investigate the anatomic appearance of Labbe vein, deep cerebral vein and the region of the torcular Herophili by using CTV and to evaluate its clinical significance. Materials and Methods 1 , Obversation items involved shape, position, distance and angle to transverse sinus of Labbe vein and its entry point to transverse sinus. 2, Images of 30 deep cerebral veins and the region of the torcular Herophili of 75 subjects were analyzed. Results 1 , The main types of Labbe vein were single, double or multiple. Entry point comeing from superior wall of transverse sinus was 66%, lateral outside wall 19%, lateral inside wall 15%. The angles to transverse sinus was 55% in cute, 32% in right, 13% in obtuse. The distance from Labbe vein to connect point between sigmoid sinus and transverse sinus was 2.5 ± 1.4cm. 2, (1) The venous drainage dominance showed mainly to the right side in 47 cases, mainly to the left side in 13 cases, equal drainage in 15 cases. (2) According to the relation among the sinuses in the region of the torcular Herophili, all subjects in this study could be grouped into 4 types: Type 1, including those subjects in which a confluence of sinuses existed or the superior sagittal sinus and the straight sinus forked, and the forking of both sinuses joined to form the lateral sinuses. Type 2, including those subjects in which the sagittal sinus drained into one side and the straight sinus drained into the other. Type 3, including those subjects in which the superior sagittal sinus and the straight sinus joined and mainly drained into the right side. Type 4, including those subjects in which the superior sagittal sinus and the straight sinus joined and mainly drained into the left side. Conclusion 1, Labbe vein show variable shapes, knowing its different conditions has important significance to instruct operative procedures. 2, CTV is a useful method to show the anatomic features of deep cerebral veins and the region of the torcular Herophili. These findings may be useful for diagnosis and operation.Part III The value of CT venography in diagnosis of the disease of cerebral blood vesselsObjective To evaluate the value of CTV in the diagnosis of cerebral venous malformation(CVM), cerebral arterial and venous malformations (cerebral AVM) and cerebral venous thrombosis (CVT). Materials and Methods 6 patients of CVM , 16 patients of cerebral AVM and 15 patients of CVT underwent CTV were studied. Among them, 3 patients of CVM and all patients of cerebral AVM were examined by CTA before CTV. Some of them were also examined by MRA, MRV and DSA. 3D vascular images of CTA and MRA were gained through workstation. DSA vascular images were got through femoral catheterization. Results 1, The shape and position of the CVM can be well displayed on CTV and the " caput medusae " sign on CTV is more typical than CTA. 2, CTV combined with CTA images could directly display the shape, size, accurate position, supplying arteries, drainage veins and vascular nests of cerebral AVMs. The supplying arteries were better demonstrated on CTA than MRA and the drainage veins were better demonstrated on CTV than MRA. Conclusion CTV is a sensitive technique in detecting lesions and diagnosing CVM, cerebral AVM and CVT. CTV has important value in the formulating treatment program, guiding operation and evaluating prognosis of these diseases. CTV combining with CTA is very important in diagnosing cerebral AVM. Part IV The clinical use of CT venography in theneurosurgeryObjective To study the relationship between the tumor and vein with CTV, the ability of CTV in revealing the supplying arteries, drainage veins of the tumor and to explore the application of the StealthStation for neuronavigation in neurosurgical operations. Materials and Methods 1, 60 patients were examined with CTV. The tumors located at petroclival region, pineal region, falcotentorial junction and Parasagittal and Parafalx. Observed the relationship between the tumor and vein on the CTV images and compared it with the operation. 2, 30 patients were examined byCTA and CTV to demonstrate the supplying arteries and drainage veins of the tumors. 3 , retrospectively analyse 26 patients with a wide range of brain tumors surgically treated on StealthStation system. The original image data were got by CTV. Results 1 , The relationship between tumor and vein is accurately demonstrated by CTV of all the patients. 2, CTA and CTV images of 30 patients were all satisfactory. The internal and surface structure, supplying arteries and drainage veins were demonstrated very well. 3, Among 26 patients, except biopsy was done in 1 case, neuronavigation guided lesionectomy in 25 cases was performed precisely. Total lesion removal was achieved in 20 cases, subtotal removal in 3 cases. No patient died. Conclusion 1, CTV technique is able to acurately demonstrate relationship between the tumor and vein and can reveal the supplying arteries and drainage veins of the tumors, thus providing great valuable data to further perfection of surgical protocol. 2, CTV can provide much information for the neuronavigation in neurosurgical operations. It is not only helpful for the total removal of lesions but also decreasing the postoperative complications.