Registration Method Between Phase-Contrast Magnetic Resonance Angiography and Time-of-Flight Magnetic Resonance Angiography—A Preliminary Study

Purpose: To evaluate a new method that registers phase-contrast magnetic resonance angiography images to time-of-flight magnetic resonance angiography images. Methods: Magnetic resonance angiography datasets of 10 healthy volunteers obtained by using two modalities (phase-contrast magnetic resonance angiography and time-of-flight magnetic resonance angiography) were preprocessed. Specifically, vessel regions were extracted using the region growing method with a threshold of 10% of the signal intensity maximum or 50% of the signal intensity maximum for phase-contrast magnetic resonance angiography images and time-of-flight magnetic resonance angiography images, respectively. Then, the normalized mutual information method was used to determine spatial positions, and registration between non-preprocessed phase-contrast magnetic resonance angiography and time-of-flight magnetic resonance angiography was performed using the spatial position information. Misalignment of 3 anatomical points was used to compare the accuracy of registration in this data group (the proposed method group) to that in the data group without registration (the non-registration group) and that in the data group subjected to normalized mutual information-based registration without preprocessing (the non-preprocessing group). Results: The mean misalignment of 3 anatomical points ± standard error was 1.69 ± 0.11 mm in the proposed method group, and 2.77± 0.13 mm and 90.28 ± 8.24 mm in the non-registration group and non-preprocessing group, respectively. The mean misalignment of 3 anatomical points was significantly smaller in the proposed method group than in the non-registration group (p = 0 001). Conclusions: The proposed preprocessing and registration method improved the accuracy of normalized mutual information-based registration between phase-contrast magnetic resonance angiography images and time-of-flight magnetic resonance angiography images.

A perspective review: Technical study of combining phase contrast magnetic resonance imaging and computational fluid dynamics for blood flow on carotid bifurcation artery

Nowadays, the knowledge of precise blood flow patterns in human blood vessels, especially focusing on Carotid Bifurcations Artery (CBA) area by using computational and modern techniques are very important to develop our understanding regarding to human diseases for both essential research and clinical treatment. This paper tends to discuss the progress regarding to the integration between Phase Contrast Magnetic Resonance Imaging (PC-MRI) and Computational Fluid Dynamics (CFD), specifically to the human diseases. We technically define the model geometry reconstruction, review both PC-MRI and CFD methods to create mesh models, obtain boundary conditions, define the governing equations in CFD, define the material properties, and assumptions used in running the CFD simulations. Detailed information on PC-MRI and CFD is provided in tables, such as the MRI setup, software used, CFD model setup, measurement parameter, and summary of the result contribution from each reviewed article. Numerous fusions between PC-MRI and CFD are specified by summarizing the investigation carried out by significant group’s research, reviewing the important outcomes, and discussing the techniques, drawbacks and possibilities for further study. We hope that this perspective analysis will encourage a fusion of PC-MRI and CFD research contributing to continuous advancement of human health with close cooperation and collaboration among clinicians and engineers.

Correction to: Phase-contrast magnetic resonance imaging to assess renal perfusion: a systematic review and statement paper

The article Phase‑contrast magnetic resonance imaging to assess renal perfusion: a systematic review and statement paper, written by Giulia Villa, Steffen Ringgaard, Ingo Hermann, Rebecca Noble, Paolo Brambilla, Dinah S. Khatir, Frank G. Zöllner, Susan T. Francis, Nicholas M. Selby, Andrea Remuzzi and Anna Caroli, was originally published electronically on the publisher’s internet portal on 17 August 2019 without open access

Evaluation of Cerebral Blood Flow Dynamics in Transient Ischemic Attacks Patients with Fast Cine Phase Contrast Magnetic Resonance Angiography

Fast cine phase contrast magnetic resonance angiography (PC-MRA) has the potential to provide a quantitative measurement method for the diagnosis and treatment of cerebrovascular disease. To evaluation the changes of cerebral blood flow and the characteristics of artery lesion distribution in the patients of transient ischemic attacks (TIA). In all, 98 normal subjects and 106 TIA patients who underwent MRI examination within 72 h after the last symptom onset including the DWI sequence to exclude acute cerebral infarction were enrolled. The blood flow of the cranial total, the area of the internal carotid artery and vertebral artery, the average velocity, and the average blood flow were obtained and compared in normal subjects and TIA group. Analysis of Variance (ANOVA), t-test, and Kruskal-Wallis test were used for statistical assessments. The total cerebral blood flow of the TIA group and normal control group was no significant statistical difference (P>0.05). The total blood flow decreased with increasing age, and the TIA group was much lower than the control group. The blood flow of the right internal carotid artery in the TIA group had a significant difference compared with controls (P<0.05). However, the same situation did not happen in both of the left internal carotid artery and vertebral artery. Phase contrast magnetic resonance imaging has the potential to evaluate the change of cerebral blood flow in TIA patients. The decrease in the total blood flow and the symptom onset of TIA is consistent. Phase contrast magnetic resonance imaging could provide guidance to the diagnosis of TIA.