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Accurate staging of Cerebral Venous Sinus Thrombosis using T1 SPACE：clinical experience1Department of Magnetic Resonance Imaging, the First Affiliate Hospital of Zhengzhou University, Zhengzhou, China, 2Department of Biomedical Engineering, School of Basic Sciences, the Sixth Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
Synopsis
This study aims to explore magnetic resonance High-resolution Variable Flip Angle Turbo-Spin-Echo(T1 SPACE) technique for accurate staging of Cerebral Venous Sinus Thrombus(CVT). CVT patients confirmed by Computed Tomographic (CT) were randomly divided into three groups according to the time from the onset of symptoms to T1 SPACE. Signal to Noise Ratio(SNR) and Contrast to Noise Ratio(CNR) between thrombus and gray tissues/white tissues were calculated on every thrombus segments and difference between different groups were analyzed. Results indicate that T1 SPACE has the potential to be a promising tool for accurate diagnosis and staging of CVT.
Introduction：
Cerebral Venous Sinus Thrombosis (CVT) is a rare，life-threatening central nervous system disease that affects young individuals frequently1. Effective treatment of CVT requires accurate evaluation of thrombus distribution and stage. However, for the non-specificity clinical manifestation and variety imaging features at different stages, accurate staging of CVT is currently a major clinical challenge2. Several imaging techniques, such as Computed Tomographic Venography (CTV), could detect CVT effectively but it cannot be used for CVT staging but also has the limitation to severe renal insufficiency for the use of iodine-based contrast medium. As the clinically approved CVT diagnosis standard, PC-MRV exhibits thrombus as filling defect, but lacks the ability to stage CVT3, High-resolution T1 SPACE imaging technique has demonstrated a super approach that can early detect CVT with a high diagnostic accuracy for it permits direct visualization of thrombus4. In this study, we sought to use T1 SPACE technique for accurate staging of CVT.Method：
This study was approved by the Institutional Review Board. 44 consecutive CVT patients (33±15 years old, 28 males, 16 females), confirmed by Computed Tomography (CT), were enrolled. MRI data were collected on a MAGNETOM Prisma 3T MR scanner (Siemens Healthcare, Erlangen, Germany) with a 64-channel head coil, including routine head scan, PC-MRV, and high-resolution T1 SPACE. The routine head scan included Fast Low Angle Shot sequence (FLASH) and T2-weighted Turbo Spin Echo (TSE) sequence. Detailed parameters of PC-MRV and the high-resolution T1 SPACE were shown in table 1.
CVT patients were divided into 3 groups based on the duration of clinical onset: acute stage (group1, ≤3 days), subacute stage (group2, between 4 days and 15 days), chronic stage ( group3, between 16 days and 30 days)5. Cerebral venous sinus images obtained from all patients were reviewed separately for 10 venous segments as follows: superior sagittal sinus, inferior sagittal sinus, right transverse sinus, right sigmoid sinus, left transverse sinus, left sigmoid sinus, straight sinus, confluence of sinuses, deep venous, and cortical veins.
Thrombus signals were measured by averaging three independent and equally distributed regions of interest (ROIs) on thrombus segment. Two kinds of CNRs were calculated between thrombus and brain tissues (mean of 4 ROIs)，including thrombus to gray matter and thrombus to white matter. In addition, SNR was calculated between thrombus and background noise drawn out from four symmetrically distributed corners of T1 SPACE images.
Statistical tests were used to assess CNRs and SNR among two different stages. Data distribution was evaluated for normality with Kolmogorov-Smirnov test and homogeneity of variance was evaluated with Levene test. One-way analysis of variance (ANOVA) was used to assess differences among different stages and Least significant difference (LSD)-t test was used for multiple pairwise comparisons.
Results：
65 thrombi segments were confirmed by CT in total. In the end, there were 7 thrombi in group 1, 36 thrombi in group 2, and 22 thrombi in group 3. A detailed overview of the quantitative results of T1 SPACE was summarized in Table 2. SNR and CNR values were all significantly different between two adjacent stages for group1 and group2 (SNR:87±18 vs.173±45; CNR: thrombus to gray matter:1.13±0.34vs.2.12±0.53; thrombus to white matter:0.84±0.17vs.1.62±0.39; both p<0.000), for group2 and group3 (SNR:173±45vs.140±40,p=0.006; CNR: thrombus to gray matter:2.12±0.53vs.1.75±0.52,p=0.009; thrombus to white matter:1.62±0.39vs.1.36±0.39;p=0.013), respectively.Discussion：
Figure 1. shows that, signals of CVT on conventional MR T1-, T2- weighted images change mutably, so it is hard to stage thrombus. PC-MRV would be filling defect when venous sinus is thromboembolic or blood stasis, which may lead to misdiagnosis of venous sinus atresia/hypoplasia or stenosis6. For the selective visualization of CVT, T1 SPACE exhibits acute thrombus as isointense, subacute thrombus as hyperintense and chronic thrombus as hyperintense/ isointense compared with brain tissues while venous lumen signals are hypointense. So T1 SPACE is more direct and convenient to stage CVT. Furtherly, our findings show that the signals of CVT change is first up in about 3-5 days, stable in about 20 days and fall to isointense or venous revascularization finally. This is because that the T1 was shortened when erythrocyte lysis–oxidation of iron turned to paramagnetic Fe3+, and then were prolonged with organization of the thrombus and recanalization7.Conclusion:
Our findings show that T1 SPACE technique provides a novel staging criteria of CVT, and can be a promising first-line staging tool.Acknowledgements
No acknowledgement found.References
1. Stam J. Thrombosis of the cerebral veins and sinuses[J]. New England Journal of Medicine, 2005, 352(17): 1791-1798.
2. Chiewvit P, Piyapittayanan S, Poungvarin N. Cerebral venous thrombosis: diagnosis dilemma[J]. Neurology international, 2011, 3(3).
3. Leach JL, Fortuna RB, Jones BV, et al. Imaging of cerebral venous thrombosis: current techniques, spectrum of findings, and diagnostic pitfalls. Radio graphics 2006;26 Suppl 1:S19–41, 10.1148/rg.26si055174.
4. Yang Q, Duan J, Fan Z, et al. Early detection and quantification of cerebral venous thrombosis by magnetic resonance black-blood thrombus imaging[J]. Stroke, 2016, 47(2): 404-409.
5. Lafitte F, Boukobza M, Guichard J P, et al. MRI and MRA for diagnosis and follow-up of cerebral venous thrombosis (CVT)[J]. Clinical radiology, 1997, 52(9): 672-679.
6. Fera F, Bono F, Messina D, et al. Comparison of different MR venography techniques for detecting transverse sinus stenosis in idiopathic intracranial hypertension[J]. Journal of neurology, 2005, 252(9): 1021-1025.
7. Saha P, Andia M E, Modarai B, et al. Magnetic Resonance T1 Relaxation Time of Venous Thrombus Is Determined by Iron Processing and Predicts Susceptibility to Lysis Clinical Perspective[J]. Circulation, 2013, 128(7): 729-736.
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