Study On The CTA And DSA In The Diagnosis Intracranial Aneurysm And The CT Vascular Imaging Techniques

Part one:Comparative Analysis of CTA and DSA in the diagnosis intracranial aneurysmsBackgroud From1972the first computer Tomography CT (Computed Tomography), since the birth of the innovation of CT machine is never stopped footstep, especially spiral CT in the1990s and the rapid development of multislice CT in nearly a decade.Compared with the previous CT, check method and great changes have taken place in the diagnostic mode.Today, the mainstream of CT machine is16,64,128or even320layers.Its advantage is to wide scan range, fast scan, layer, layer thickness, high resolution.CT64layers, for example, had come up to40per second, transverse and longitudinal resolution is0.3mm and0.4mm respectively.Compared to the past1/3～5min, there have been a qualitative leap.In addition, in addition to the development of CT machine Bunsen, computer hardware and software technology in the last ten years of rapid development and further into the image processing of CT machine, also contribute to more CT image post-processing, promote the improvement of image quality and imaging mode change, requirements for image processing is more close to follow one’s inclinations.In this case, based on the CT angiography has also been the CTA huge development.Big body can get good development by CTA examination.Intracranial aneurysm (intracranial aneurysm, IAN) is a common cerebrovascular disease, mainly for intracranial arterial wall bulging local anomalies, mostly due to congenital intracranial artery developmental defect with tube cavity pressure caused by a sudden increase.IAN not burst, the majority of patients with no obvious symptoms, or symptom is slight, Only show the ordinary dizziness, headache, a few level performance for moving eyes paralysis, slight disturbance of consciousness, etc., so clinical extremely easily missed diagnosis or misdiagnosis;But IAN burst, most patients with the clinical symptoms of subarachnoid hemorrhage, intense headache, frequent vomiting, aphasia and numbness, even in a coma and so on, these patients in clinic belonged to acute and dangerous, serious illness, more serious is the first time IAN broken tend to occur again within a few hours to a few days break and early vascular spasm, patients with a high mortality and morbidity.Timely make an accurate diagnosis in patients with IAN plays an important role in the treatment and prognosis.Therefore, looking for accurate and rapid vascular diagnosis method is a key point in the research of IAN clinical, head of digital subtraction angiography (DSA) is to put the angiographic images of digital information and angiography image subtraction to obtain vascular imaging, digital information is developed in recent years, IAN examination method, clinical application is extensive, was unanimously considered IAN diagnostic gold standar.In recent years, as more row helical CT and the development of computer technology and developed the CTA is widely used in clinical, CTA is volume scanning, again through the computer and3d reconstruction of volume data post-processing subtraction angiography vascular images are obtained.Cranial CTA and DSA are vascular imaging method, but there is a a DSA examination, testing time is long, the patient cost higher shortcomings and make the patient is not easy to accept, in contrast, head CTA simple operation, check the fast, low cost;More importantly, because of the characteristic of the examination itself, determines the CTA examination for patients with medical exposure dose and occupational exposure dose is far less than that caused by DSA to the doctor, in the public in current medical exposure dose and occupational exposure dose is becoming more and more attention, intracranial vascular imaging CTA has become more and more widely in the clinical application, and has a tendency to replace DSA examination.The author combines own work practice, the IAN by CTA inspection with DSA examination of all the advantages to make comparative analysis.Objective to analyse the head3d-CTA and DSA was applied to the diagnosis of intracranial aneurysm effect, to explore the value of CTA in clinical rapid diagnosis of intracranial aneurysms.Method (1) since December2011-2013were retrospectively analyzed in October of157cases admitted in a hospital of guangzhou medical university by imaging examination or surgery patients with a diagnosis of intracranial aneurysms after head CTA and DSA examination materials, among which83were male, female74cases, the biggest age was79, the minimum age is28years old, the average age of55.3years.All patients were respectively line head CTA and DSA examination, inspection interval for6h.By A, B two groups of radiology has A subtropical high title, is engaged in the imaging diagnosis of15years of doctor (three doctors in each group), respectively, the results of3d-CTA and DSA examination for independent double-blind interpretation to determine, namely the CTA157copies of the image data to A group of doctors diagnose, given157video images of DSA to group B the doctor diagnosis.By each group of doctors finally discussed the comprehensive diagnosis for the diagnosis. Evaluation of3d-CTA and DSA of intracranial aneurysm diagnosed sensitivity and specificity;(2) randomly selected48were detected with IAN, respectively on CTA and DSA images tumors had the longest diameter (D) measurement, and compare the two kinds of inspection in tumors had the longest diameter measuring differences, all measurements in the post-processing workstation processing, rotation Angle in order to obtain the best exposure, and convenience can be appropriately enlarge images.(3) according to the CTA inspection machine according to the patient after the X-ray radiation dose and DSA examination information machine plate center after the completion of the cumulative dose data, statistical patients in general X-ray radiation dose, with CTA examination of patients with general X-ray radiation dose for the standard, in the CTA and DSA examination were compared by differences in general X-ray radiation dose, and DSA for the operation on two different doctors to patients by the radiation dose difference.(4) according to the contrast medium in the process of imaging in patients with use dose, comparing CTA and DSA examination in the difference of contrast medium dose required.Results (1) skull CTA detected148cases (94%), IAN,9cases of false negative and DSA detected151cases (96%), IAN,6cases of false negative, both in terms of accuracy had no significant difference (P>0.05).(2) on the CTA images measured IAN tumors had the longest diameter=5.495±1.743mm, the average number of D measure on DSA images tumors had the longest average diameter D=5.503±1.739mm, the two methods in the measurement of the tumors had the longest diameter had no significant difference (P>0.05).(3) skull CTA check patients medical X-ray dose of median950mgy, DSA examination to the patients’ medical X-ray radiation dose is1070mgy, both patients caused by medical radiation dose of significant difference (P<0.05).(4) the CTA examination, the patient required for injection of contrast medium dose mean was79.167±5.941ml, DSA examination, the patient required injection of contrast medium dose mean was208.938±17.037ml, both contrast medium doses required significant difference (P<0.05) conclusion (1) skull CTA and DSA in diagnosis of intracranial aneurysms are equally the sensitivity and specificity.(2) from patients with reduced X-ray radiation dose into consideration, head CTA can be used as the first choice for the intracranial aneurysms.Good3d skull-DSA examination before the skull CTA examination, should become clinical routine.(3) the CTA and DSA on the efficiency of the tumors had the longest diameter of IAN are equally.(4) the CTA significantly less than DSA on the amount of contrast medium, because of contrast agent has certain kidney toxicity, so the CTA with DSA reduces the potential hazards in kidney function.Part tow:discuss the CT angiography imaging technologyBackgroud Vascular imaging is transvenous rapid injection of organic iodine contrast agent, at the height of target vessel contrast medium filling trigger spiral scan, one of the keys to its success or failure is the acquisition of intravascular contrast medium concentration.As CT machine scanning speed faster and faster, how to in a timely manner to capture the arteries phase has become more and more important.All the scanning technology application, and the current clinical lack of objective advantage, based on this the author CT vascular imaging techniques to explore.Objective study the optimal scanning methods of CT angiography, improve the quality of images of the vascular imaging.Methods (1) select60patients with intracranial CT angiography, were randomly divided into A, B, C three groups, each group of20.A, B, C three groups respectively using experience blind sweep method (note medicine after15～20s start scanning), macroscopic observation and compare manual trigger method (dynamic observation vascular contrast medium concentration) and peak tracking scanning method.(2).60patients after scan, the images of CT value measure and record the data, all measurement data in Vitrea workstation.By two radiologists has subtropical high title work15years of doctors to determine, in the image of intracranial vascular choose three testing point, respectively is in the left cervical artery and the left common carotid artery and the Willis arteries of the skull base ring RIO intracavitary placed areas of interest, covers an area of about5was;In the near the anterior cerebral artery, middle cerebral artery proximal M1segment and the basal artery respectively placed three RIO, covers an area of about2was, RIO should as far as possible in the central area of blood vessel, to avoid the influence of vascular value measurement organization, such as bone, calcifications and fat, the CT values of measured, calculating the mean.(3) all image observed by two radiologists has subtropical high title work full15years physicians with double blind method in image post-processing workstation.Image quality score and reference Cao Lizhen scoring criteria proposed by grading index includes:(1). The left cervical artery and the left common carotid artery showed:the edge is smooth, show clear, with the surrounding tissue area distinguish for1minute;Edge blur, according to the general, compared with the surrounding tissue to fair for2points;Display is poorer, the edge is coarse, and surrounding tissues to distinguish the difference of three points.(2). On the base of Willis circle of Willis display:display clear, distal branches more than1;According to fair, distal branches for2minutes and less;Display is poor, the remote branch for three points less.(3). The recent the anterior cerebral artery, middle cerebral artery M1segment in the proximal basilar artery and artifacts produced by the high concentration of contrast medium:no obvious artifacts for1minute; Some artifacts, but does not affect artery observation for2minutes;Artifacts, artery observation affected for three points.Results all cases were satisfied to complete the cerebral CT, the whole process of no special accident.(1) the three groups of patients with neck and cerebrovascular contrast medium filling the comparison of CT values, the left cervical artery CT value and CT value of the left common carotid artery and the base of Willis circle of Willis and comparing two CT value, A, B, no significant differences between the two groups (P>0.05), group C and A, B two groups all have significant difference (P<0.05), the image of group C reinforcement value were higher than A brain carotid artery, group B and C the arterial tree contrast of the two groups are also A, group B clear;Type A, B, the image is no significant difference between the two groups (P>0.05).The artery image shows A, B two methods of reinforcement value difference.(2) the comparison of three groups of patients with neck and cerebrovascular image quality by two radiologists has a subtropical high title of physician in the near the anterior cerebral artery, middle cerebral artery proximal M1segment and basal artery showed on the image quality evaluation, evaluation results of two doctors consistency is very good.(3) three groups of patients in the near the anterior cerebral artery, middle cerebral artery proximal M1segment and basal artery showed on the image quality score, group C and A, B two groups all have significant difference (P<0.05), A, B two groups no significant difference (P>0.05).Image quality C method is superior to A, B two groups;And there was no significant difference in group A and group B image significance (P>0.05). Shows A, B two methods but there was no difference in the quality of images collected.Conclusion using peak tracking scanning method is a better CTA scanning method, can effectively improve the quality of vascular imaging, scanning should be advocating the use of the method for vascular imaging.