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Herein, 4D-flow MRI was performed on the bilateral carotid arteries in a rat model of unilateral carotid artery injury to analyze changes in flow velocity, flow rate, wall shear stress (WSS), and cross-sectional area due to endothelial injury. MR images of the rat carotid artery were acquired using 7T-MRI. Seven control rats and 16 rats with right endothelial injury (VED) were used. For five of the VED models where blood flow in both the right and left common carotid arteries was confirmed, 4D-flow MRI was performed after obtaining 3D images using the time of flight method. MRI was performed to calculate the flow velocity, flow rate, WSS, and cross-sectional area of the proximal, middle, and distal carotid arteries. In all five VED models, blood flow rate and WSS were predominantly decreased at the proximal injured side compared to the ipsilateral control side ( p  < 0.05). The cross-sectional area of the vessel distal to the injured side of the VED model was reduced compared to that of the non-injured side ( p  < 0.05). A comparison of the proximal part of the uninjured side between the control group and VED model showed that the vascular cross-sectional area was predominantly increased in the VED model ( p  < 0.05). 4D-flow MRI with 7T-MRI enabled analysis of changes in flow velocity, flow rate, WSS, and cross-sectional area due to vascular endothelial injury.

We aimed to assess tumor growth and cell density in colon cancer-bearing mouse models using CEST and diffusion-weighted imaging (DWI). Mouse carcinoma models were created by transplanting the mouse colon cancer cell line colon-26. They were divided into three groups at 6, 8, and 10 days after transplantation and underwent T 2 WI, CEST, and DWI using 7T-MRI. The Magnetization Transfer Ratio asymmetry (MTR) of 1.2 ppm reflecting hydroxyl metabolite in CEST imaging and the apparent diffusion coefficient (ADC) of the same region were statistically analyzed for each group. The MTR and ADC values were 6.51 ± 3.47% and 1.14 ± 0.34 × 10 − 3 mm 2 /s, 3.65 ± 1.65% and 0.77 ± 0.20 × 10 − 3 mm 2 /s, and 2.84 ± 0.82%, and 0.54 ± 0.02 × 10 − 3 × mm 2 /s on days 6, 8, and 10, respectively. The MTR and ADC values were high at 6 days after cell transplantation, and both values tended to decrease with tumor growth. These results indicate that hydroxyl metabolism was high on the sixth day, and both values decreased after the eighth day. CEST imaging and DWI may be useful markers of cell proliferation and metabolism in tumors.

Background/Objectives: The Glutamate Chemical Exchange Saturation Transfer (GluCEST) technique is an advanced imaging modality that enables non-invasive glutamate quantification using MRI. Methods: This study evaluated glutamate dynamics in Parkinson’s disease (PD) using a unilateral PD rat model, in which Wistar rats received 6-hydroxydopamine (6-OHDA) injections into the medial forebrain bundle, selectively eliminating dopaminergic neurons in the substantia nigra–striatum pathway. Results: The PD rat model exhibited a significant GluCEST increase (MTR Values: 3.0 ppm) compared to the sham-operated group, which was suppressed by administration of L-DOPA, a dopamine precursor drug (Sham: 0.9 ± 0.4%, PD: 2.0 ± 0.2%, Sham L-DOPA: 0.9 ± 0.5%, PD_L-DOPA: 0.8 ± 0.7%, p < 0.01). Additionally, magnetic resonance spectroscopy-derived glutamate data were consistent with GluCEST findings (Sham: 1.4 ± 0.03, PD: 1.7 ± 0.06, Sham_L-DOPA: 1.4 ± 0.12, PD_L-DOPA: 1.4 ± 0.10, p < 0.01). Conclusions: These findings suggest that GluCEST and magnetic resonance spectroscopy are valuable for assessing abnormal glutamate dynamics in the 6-OHDA-induced rat PD model. Furthermore, GluCEST may detect suppressed glutamate secretion following L-DOPA treatment, underscoring its potential for monitoring disease progression and therapeutic responses in PD.