Simulated Diffusion Weighted Images Based on Model-Predicted Tumor Growth

Abstract Background Although acute vestibular syndrome (AVS) and episodic vestibular syndrome (EVS) are an increasingly recognized cause of acute ischemic stroke, the predilection sites of AVS/EVS caused by acute ischemic stroke still is less known. Methods From Mar 2014 to Mar 2016 period, we used a new approach of 11thedition of the International Classification of Diseases (ICD-11) to retrospectively enrolled patients with identified AVS/EVS events caused by acute ischemic stroke in the stroke center of tertiary teaching hospital. The patients who had positive diffusion-weighted images (DWI) lesion and MRA were analyzed. Multivariable logistic regression was used to identify the risk of stroke causing AVS/EVS. Results Among 181 AVS/EVS patients with ischemic stroke, 68 (37.6%) patients with acute ischemic stroke were proved by DWI. Of them, the most frequent type was EVS (60.3%); the predilection sites of stroke was in the insular (51.7%, 15/29) in the anterior circulation artery (ACA), followed by the posterior of thalamus (28.6%, 8/28) in the posterior circulation artery (PCA). The lesion on DWI showed a median diameter of 4.0mm (range,0.6-89.4). The risk of AVS/EVS in acute ischemic stroke was found in association with large vessel stenosis/ occlusion (odds ratio[OR],, 0.12; 95% confidence interval [CI], 0.040-0.357), focal neurological symptom /sign (OR, 0.27; 95% CI, 0.104-0.751), and higher initial ABCD2 score (OR, 0.37; 95% CI, 0.239-0.573). Conclusions The predilection site of the AVS/EVS caused by acute ischemic stroke is in the insular. The risk of AVS/EVS was associated with a large vessel stenosis, focal neurological symptoms, and higher initial ABCD2 score.

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Clinical application of three-dimensional anisotropy contrast magnetic resonance axonography

Journal of Neurosurgery ◽

10.3171/jns.1999.90.4.0791 ◽

1999 ◽

Vol 90 (4) ◽

pp. 791-795 ◽

Cited By ~ 58

Author(s):

Tsutomu Nakada ◽

Naoki Nakayama ◽

Yukihiko Fujii ◽

Ingrid L. Kwee

Keyword(s):

Magnetic Resonance ◽

Healthy Volunteers ◽

Clinical Application ◽

Color Image ◽

Three Dimensional ◽

Cerebral Peduncle ◽

Imaging Method ◽

Medial Lemniscus ◽

Diffusion Weighted Images ◽

Diffusion Weighted

✓ The utility of three-dimensional anisotropy contrast (3DAC) magnetic resonance (MR) axonography, a method sensitive to neuronal fibers and their directionality, was investigated in the clinical setting using a 3-tesla MR imaging system based on a General Electric Signa platform. The study focused on healthy volunteers and patients with common structural central nervous system disorders, namely chronic infarction, brainstem cavernous hemangioma, supratentorial meningioma, and astrocytoma. Three orthogonal anisotropic diffusion-weighted images were first obtained. Three primary colors were each assigned to a diffusion-weighted image, respectively, and the images were subsequently combined into a single-color image in full-color spectrum (3DAC MR axonography image). Fiber-tract definition in the cerebral peduncle of the midbrain of healthy volunteers showed intersubject variation, with two general patterns recognized: dispersed (60% of cases) and compact (40% of cases). Pathological alterations in the fiber tracts were readily identified in cases involving wallerian degeneration of the pyramidal tract, as illustrated in the cases of chronic infarction. Displacement of major tracts, such as the medial lemniscus or corticospinal tract, as well as fiber directionality, was also easily recognized in cases of mass lesions. As an imaging method uniquely capable of providing information regarding axonal connectivity, 3DAC MR axonography appears to have promising potential for routine clinical application.

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DCE-MRI is more sensitive than IVIM-DWI for assessing anti-angiogenic treatment-induced changes in colorectal liver metastases

Cancer Imaging ◽

10.1186/s40644-021-00436-0 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Mihaela Rata ◽

Khurum Khan ◽

David J Collins ◽

Dow-Mu Koh ◽

Nina Tunariu ◽

...

Keyword(s):

Liver Metastases ◽

Colorectal Liver Metastases ◽

Tissue Perfusion ◽

Post Treatment ◽

Rank Tests ◽

Transfer Constant ◽

Significant Treatment ◽

Dce Mri ◽

Diffusion Weighted Images ◽

Diffusion Weighted

Abstract Background Diffusion weighted imaging (DWI) with intravoxel incoherent motion (IVIM) modelling can inform on tissue perfusion without exogenous contrast administration. Dynamic-contrast-enhanced (DCE) MRI can also characterise tissue perfusion, but requires a bolus injection of a Gadolinium-based contrast agent. This study compares the use of DCE-MRI and IVIM-DWI methods in assessing response to anti-angiogenic treatment in patients with colorectal liver metastases in a cohort with confirmed treatment response. Methods This prospective imaging study enrolled 25 participants with colorectal liver metastases to receive Regorafenib treatment. A target metastasis > 2 cm in each patient was imaged before and at 15 days after treatment on a 1.5T MR scanner using slice-matched IVIM-DWI and DCE-MRI protocols. MRI data were motion-corrected and tumour volumes of interest drawn on b=900 s/mm2 diffusion-weighted images were transferred to DCE-MRI data for further analysis. The median value of four IVIM-DWI parameters [diffusion coefficient D (10−3 mm2/s), perfusion fraction f (ml/ml), pseudodiffusion coefficient D* (10−3 mm2/s), and their product fD* (mm2/s)] and three DCE-MRI parameters [volume transfer constant Ktrans (min−1), enhancement fraction EF (%), and their product KEF (min−1)] were recorded at each visit, before and after treatment. Changes in pre- and post-treatment measurements of all MR parameters were assessed using Wilcoxon signed-rank tests (P<0.05 was considered significant). DCE-MRI and IVIM-DWI parameter correlations were evaluated with Spearman rank tests. Functional MR parameters were also compared against Response Evaluation Criteria In Solid Tumours v.1.1 (RECIST) evaluations. Results Significant treatment-induced reductions of DCE-MRI parameters across the cohort were observed for EF (91.2 to 50.8%, P<0.001), KEF (0.095 to 0.045 min−1, P<0.001) and Ktrans (0.109 to 0.078 min−1, P=0.002). For IVIM-DWI, only D (a non-perfusion parameter) increased significantly post treatment (0.83 to 0.97 × 10−3 mm2/s, P<0.001), while perfusion-related parameters showed no change. No strong correlations were found between DCE-MRI and IVIM-DWI parameters. A moderate correlation was found, after treatment, between Ktrans and D* (r=0.60; P=0.002) and fD* (r=0.67; P<0.001). When compared to RECIST v.1.1 evaluations, KEF and D correctly identified most clinical responders, whilst non-responders were incorrectly identified. Conclusion IVIM-DWI perfusion-related parameters showed limited sensitivity to the anti-angiogenic effects of Regorafenib treatment in colorectal liver metastases and showed low correlation with DCE-MRI parameters, despite profound and significant post-treatment reductions in DCE-MRI measurements. Trial registration NCT03010722 clinicaltrials.gov; registration date 6th January 2015.

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