This retrospective study was carried out according to relevant guidelines and regulations. The Ethics committee of Mashhad University of Medical Sciences
(MUMS) approved this retrospective observational study. The review board at MUMS waived informed consent due to the observational nature of the research, under the waiver statement IR.MUMS.MEDICAL.REC.1398.470.
all methods were performed in accordance with the relevant guidelines and regulations.
We searched our Picture Archiving and Communicating System (PACS) of our tertiary-level academic hospital between March 2016 and March 2019, and collected all patients for whom both contrast-enhanced MRV and brain CTA were acquired at the same admission. Inclusion criteria were patients with acute neurologic symptoms who were evaluated for CVT, age above eighteen years, available CE-MRV and a brain CTA obtained within seven days from MRV. The exclusion criteria were the presence of severe artifacts in MRV or CTA making the interpretation challenging and incomplete imaging protocol. A total of 245 adult patients were identified. The mean age of patients was 42.5 (+ 15.2) years. There were 104 (42.4%) male and 141 (57.6%) female patients.
All MDCTA examinations were performed with a commercially available 16-MDCT scanner (Neusoft, Neuviz 16). All patients received 150mL of contrast material with the flow rate of 4mL/sec, followed by 50mL of saline chaser injected with the same flow rate.
MR imaging was performed on 1.5T scanner (MagnetomVision; Avanto; I- class), including diffusion-weighted images (TR, 3500ms; TE, 104 ms; section thickness, 5.5 mm; B-value, 1000), axial proton attenuation-and T2-weighted images, ( TR, 4020 ms; TE 107 ms; section thickness, 5 mm), T1-weighted (TR, 388 ms; TE, 15ms; section thickness, 5 mm), coronal fluid-attenuated inversion recovery (FLAIR) (TR, 9610 ms; TE, 90ms;TI, 2564.5 ms; section thickness, 5 mm) sequence, and venous 2D time-of-flight (TOF) MR angiography (TR,31 ms;TE, 7.86 ms ; flip angle, 60°; section thickness, 3 mm) with superior arterial saturation pulses.
Two radiologists assessed datasets independently. They were both blind to the clinical information of patients. Image interpretation was performed on a standard PACS workstation. They were first asked to assess the MDCTA images regarding the presence of artifacts and quality of contrast enhancement in the venous vasculature on a 5-point scale (5, no artifacts/excellent contrast; 4, few artifacts/good contrast; 3, moderate amount of artifacts/moderate contrast; 2, pronounced artifacts/poor contrast; 1, images uninterpretable because of artifacts/insufficient contrast). Subsequently they were asked to record whether the quality of images was sufficient for diagnostic evaluation. 18 They then assessed the MDCTA images regarding the presence/absence of CVT in the following six venous sinus segments: superior sagittal sinus, right transverse sinus, left transverse sinus, right sigmoid sinus, left sigmoid sinus and straight sinus. In cases of CVT, the presence of venous infarct, hemorrhage and other complications was recorded. In addition, the presence of an alternative diagnosis was documented. Finally, the diagnostic confidence about the presence or absence of a venous thrombosis was rated on a 5-point scale (5, absolutely certain; 4, very certain; 3 certain; 2, not very certain; 1, uncertain). 18 The readers could use multiplanar reconstruction (MPR) and intensity projection techniques at their convenience. They then tackled the discrepancies via discussion, and the consensus data are recorded here.
After having evaluated all MDCTA datasets, the readers evaluated the MRI + CE-MRV images as the reference standard in a separate session. In cases that two radiologists did not agree on the result of an MRI + MRV image, a third radiologist, who was blind to the diagnosis of the first two, was asked to review the images. MRI images were evaluated in addition to CE-MRV images to increase the diagnostic accuracy. To eliminate recall bias, the MRI + CE-MRV mages were interpreted at least 4 weeks after MDCTA dataset evaluation.
All the obtained data were collected on a database. Sensitivity, specificity, and diagnostic accuracy of MDCTA for diagnosis of CVT were calculated, considering CE-MRV results as the gold standard. Data were analyzed using IBM SPSS version 22. A p-value of less than 0.05 was considered as statistically significant.
The personal information of patients, including names, were removed from the images and was replaced with a code unique to every individual. The medical and personal information of patient were not shared outside the research group without their written consent. This study was approved by the ethics committee of Mashhad university of medical sciences (approval code: IR.MUMS.MEDICAL.REC.1398.470). The review board waived informed consent due to the observational nature of the research.
Availability of Data and Materials
The datasets used and/or analyzed during the current study is available from the corresponding author on reasonable request