Susceptibility-Weighted Imaging of the Anatomic Variation of Thalamostriate Vein and Its Tributaries

RESEARCH ARTICLE Susceptibility-Weighted Imaging of the Anatomic Variation of Thalamostriate Vein and Its Tributaries Xiao-fen Zhang1, Jian-ce Li2, Xin-dong Wen2, Chuan-gen Ren2, Ming Cai3, Chengchun Chen1* 1 Department of Human Anatomy, Wenzhou Medical University, Wenzhou, Zhejiang, China, 2 Department of Radiology, the 1st Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China, 3 Department of Neurosurgery, the 2nd Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China * Abstract Background and Purpose OPEN ACCESS Citation: Zhang X-f, Li J-c, Wen X-d, Ren C-g, Cai M, Chen C-c (2015) Susceptibility-Weighted Imaging of the Anatomic Variation of Thalamostriate Vein and Its Tributaries. PLoS ONE 10(10): e0141513. doi:10.1371/journal.pone.0141513 Editor: Heye Zhang, Shenzhen institutes of advanced technology, CHINA Received: June 30, 2015 Accepted: October 7, 2015 Published: October 27, 2015 Copyright: © 2015 Zhang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the paper. Funding: This work was supported by the Natural Science Foundation of Zhejiang Province, China (NO. LY15C110001). Competing Interests: The authors have declared that no competing interests exist. Thalamostriate vein (TSV) is an important tributary of the internal cerebral vein, which mainly drains the basal ganglia and deep medulla. The purpose of this study was to explore the anatomic variation and quality of TSV and its smaller tributaries using susceptibilityweighted imaging (SWI). Methods We acquired SWI images in 40 volunteers on a 3.0T MR system using an 8-channel high-resolution phased array coil. The frequencies of the TSV and its tributaries were evaluated. We classified TSV into types I (forming a venous angle) and II (forming a false venous angle). We classified anterior caudate vein (ACV)into types 1 (1 trunk) and 2 (2 trunks) as well as into types A (joiningTSV), B (joining anterior septal vein), and C (joining the angle of both veins). Results The TSV drains the areas of caudate nucleus, internal capsule,lentiform nucleus, external capsule, claustrum, extreme capsule and the white matter of the frontoparietal lobes,except thalamus. The frequencies of the TSV, ACV and transverse caudate vein (ACV) were 92.5%, 87.5% and 63.8%, respectively. We found TSV types I and II in 79.7%, and 20.3% with significantly different constitution ratios (P< 0.05). The most common types of ACV were type 1 (90.0%) and type A (64.3%). Conclusion The complex three-dimensional (3D) venous architecture of TSV and its small tributaries manifests great variation, with significant and practical implications for neurosurgery. PLOS ONE | DOI:10.1371/journal.pone.0141513 October 27, 2015 1 / 11 Susceptibility-Weighted Imaging of Thalamostriate Vein Introduction Susceptibility-weighted imaging (SWI) is a relatively new MR imaging technique based on variation in blood oxygenation between venous blood andsurrounding cerebral parenchyma [1]. The differences in magnetic susceptibility between oxygenated and deoxygenated haemoglobin are delineated by SWI in terms of large (diameter approximately 1mm) and small (diameter less than 1 mm) veins in the brain using a long TE, 3D gradient-echo MR sequence [2]. Digital subtraction angiography (DSA) remains the gold standard for measurement of vessel dimensions invivo, but is an invasive technique showing unilateral veins [3]. The most widely used and relatively appropriate technique is magnetic resonance venography (MRV) which is limited in its ability to visualize small vessels [4]. SWI is significantly superior to MRV [4] with regard to smaller venous structures and DSA [5], without the need for intravenous contrast agent. In recent decades, several studies have used the technique to investigate deep cerebral veins [5, 6], cerebellar veins [7]and spinal veins [8, 9]. Thalamostriate vein (TSV) is the largest tributary of internal cerebral vein, which mainly drains the areas of basal nuclei and frontoparietal white matter. In neurosurgery of the third ventricle, TSV or theforamen of Monro is frequently used as a ventricular landmark [10, 11]. We often occluded TSV for a wider exposure to the third ventricle [12]. However, Mohamed et al. [13] suggest that deliberate occlusion of TSV should be performed only when absolutely necessary to avoid the risk of infarcts of the basal nuclei. Therefore, a thorough understanding of the anatomic variation of TSV and its tributaries is imperative. To our knowledge, studies investigating the anatomy of TSV and its tributaries are limited. The purpose of this study was to explore the normal anatomy of TSV and its anatomic variations and small tributaries using SWI invivo. Materials and Methods Volunteer Selection A total of 40 healthy adult volunteers (22 Females and 18 males; age range, 20–35; mean age, 26) were included. The absence of cerebral and other intracranial diseaseswas confirmed in all volunteers. All participants signed informed consent and were informed of the potential side effects of 3.0T MRI, including vertigo, nausea, and claustrophobia. The study design was approved by the Ethics Committee of Wenzhou Medical University. MRI All healthy volunteers were examined on a 3T MR system (Royal Philips Electronics, Amsterdam, The Netherlands)using an 8-channelhigh-resolution phased array coil. The following sequences were performed: (1)T1-weighted imaging(T1WI) and fluid-attenuated inversion recovery(FLAIR) sequence(repetition time [TR]1900 ms, echo time [TE] 20 ms, flip angle 90°, matrix 256 ×141, section thickness 6 mm, gap between sections 1 mm and field of view [FOV] 230 mm); (2)T2-weighted imaging (T2WI) and turbo spin-echo (TSE) sequence(TR 2100 ms, TE 80 ms, flip angle 90°, matrix 352 × 285, section thickness 6 mm, gap between sections 1 mm and FOV 230 mm); (3)T2 FLAIR sequence (TR 6000 ms, TE 123 ms, flip angle 90°, matrix 268 × 143, section thickness 6 mm, gap between sections 1 mm and FOV 230 mm); (4)diffusion-weighted imaging (DWI)(TR2600 ms, TE 89 ms, flip angle 90°, matrix 128×128, section thickness 6 mm, gap between sections 1 mm and FOV 230 mm); (5)magnetic resonance venography (MRV) used venographic 3D principal component analysis including sensitivity(VEN3D-PCA-SENSE) (TR 17 ms, TE 6 ms, flip angle 10°, matrix 192 × 116, NEX 1,section PLOS ONE | DOI:10.1371/journal.pone.0141513 October 27, 2015 2 / 11 Susceptibility-Weighted Imaging of Thalamostriate Vein thickness 1 mm and FOV 230 mm); and (6)SWI(VEN-BOLD) (TR 21 ms, TE 32 ms, flip angle 10°, matrix 316 × 362, section thickness 1 mm, gap between sections -0.5 mm and FOV 220 mm). Image Processing Images were processed using the Extended MR WorkSpace release 2.6.3 (...truncated)