Optimization of non-contrast-enhanced MR angiography of the renal artery with three-dimensional balanced steady-state free-precession and time-spatial labeling inversion pulse (time-SLIP) at 3T MRI, in relation to age and blood velocity

Comparison of 3D BFFE and 3D TRANCE on pulmonary artery imaging with two T-SLIP placement strategies

3D BFFE and TRANCE can provide a visualization of pulmonary vessels without injection of contrast agent. T-SLIP can observe a large area of vessels using an arterial spin labeling technique. 3D BFFE and TRANCE with two T-SLIP placement strategies were compared on pulmonary artery imaging. Ten male and thirteen female healthy volunteers were recruited in the present study. Each subject underwent non-contrast-enhanced pulmonary MRA. Four protocols were involved in the present study as follows: 3D BFFE with T-SLIP covering vena cava (VC) and right atrium and ventricle (RV), respectively; 3D TRANCE with T-SLIP covering VC and RV, respectively. The SNR were measured at eight ROIs, while CNR were measured at five ROIs. The number of visualized branch and image quality were analyzed by two radiologists. The differences of metrics among different imaging strategies were compared. SNR and CNR were compared between two T-SLIP placement strategies using a paired t-test. The branches number and image quality were compared between two T-SLIP placement strategies using a rank-sum test. The agreement of subjective assessment was conducted using a Kappa test. There were significant differences at all ROIs between TRANCE and BFEE with T-SLIP on RV (all P values <0.01). TRANCE with T-SLIP on RV exhibited a higher CNR at all five ROIs compared with BFFE with T-SLIP on RV. TRANCE with T-SLIP on RV performed better on the number of observed branches and image quality compared with BFFE with T-SLIP on RV. 3D TRANCE with T-SLIP on RV can provide a higher SNR and image quality among four MR protocols, and thus may be a potential non-contrast enhanced technique in the visualization of pulmonary artery.

Non-contrast MR angiography: physical principles and clinical applications in chest, abdomen and pelvis imaging

This review article focuses on the advancements in non-contrast magnetic resonance angiography (NC-MRA) and its increasing importance in body imaging, especially for patients with renal complications, pregnant women, and children. It highlights the relevance of NC-MRA in chest, abdominal, and pelvis imaging and details various bright-blood NC-MRA techniques like cardiac-gated 3D Fast Spin Echo (FSE), balanced Steady-State Free Precession (bSSFP), Arterial Spin Labeling (ASL), and 4D flow methods. The article explains the operational principles of these techniques, their clinical applications, and their advantages over traditional contrast-enhanced methods. Special attention is given to the utility of these techniques in diverse imaging scenarios, including liver, renal, and pelvic imaging. The article underscores the growing importance of NC-MRA in medical diagnostics, offering insights into current practices and potential future developments. This comprehensive review is a valuable resource for radiologists and clinicians, emphasizing NC-MRA's role in enhancing patient care and diagnostic accuracy across various medical conditions.

Non-contrast MR portography using time-spatial labeling inversion pulse for diagnosis of portal vein pathology

Background

To study the ability of non-contrast MR portography using time-spatial labeling inversion pulse (T-SLIP) as a non-invasive contrast-free imaging modality to delineate different portal vein pathological conditions.

The study included 25 patients with known history of portal vein disease and another 25 age-matched patients with normal portal vein. Both groups were examined by respiratory-triggered non-contrast MR portography using time-spatial labeling inversion pulse technique. Image quality was assessed first, and findings of diagnostic scans were compared to color duplex ultrasonography and selectively in those with diseased portal vein to portal-phase images of dynamic contrast-enhanced MRI.

Results

Significant relation was found between breathing regularity and image quality in T-SLIP sequence, with diagnostic scans sensitivity and specificity of 89.29% and 86.21%, respectively, for diagnosis of different portal vein pathological conditions.

Conclusions

Non-contrast MR portography is a useful technique for diagnosis of portal vein pathology in carefully selected patients.