Renal Artery Assessment with Nonenhanced Steady-State Free Precession versus Contrast-enhanced MR Angiography

140

Noncontrast‐enhanced magnetic resonance angiography (NCE‐MRA) methods have been demonstrated in anatomies throughout the body. Previously established NCE‐MRA techniques suffered from long scan times or low sensitivity. Advances in hardware and software have made NCE‐MRA scan times clinically feasible. Recent concerns over the safety of gadolinium‐based contrast material combined with the expense of the material and its administration have generated a demand for NCE‐MRA. In response, several new NCE‐MRA methods have been developed. The physical mechanisms underlying five general classes of NCE‐MRA methods (inflow effect, flow‐dependency on cardiac phase, flow‐encoding, spin labeling, and relaxation) are explained. The original techniques of time‐of‐flight (TOF) and phase contrast MRA (PC‐MRA) are briefly introduced. New developments in NCE‐MRA, including hybrid of opposite‐contrast (HOP‐MRA), four dimensional PC‐MRA (4D Flow), cardiac‐gated 3D fast‐spin‐echo, flow‐sensitive dephasing (FSD), arterial spin labeling (ASL), and balanced steady‐state free‐precession (bSSFP) are highlighted. The primary applications, advantages, and limitations of established and emerging NCE‐MRA techniques are discussed. J. Magn. Reson. Imaging 2012;36:286–304. © 2012 Wiley Periodicals, Inc.

Section: Applicationsmentioning

confidence: 99%

Non‐contrast enhanced MR angiography: Physical principles

Wheaton

Miyazaki

2012

140

“…The use of Bal-SSFP for the evaluation of renal arteries has been reported by several investigators with promising results (38,(44)(45)(46)(47)(48)(49). The main advantages of Bal-SSFP are a high signal to noise ratio, T2/T1-weighted image contrast (making blood intrinsically bright independent of flow), speed, and relative flow insensitivity (50,51).…”

Section: Balanced-steady-state Free Precession Mramentioning

confidence: 99%

“…In 2007, Wyttenbach et al reported a much larger 57 patient blinded comparison between an ECG-triggered Bal-SSFP sequence and CE-MRA for the evaluation of the aorta and renal arteries (45). Sequence parameters are shown in Table 2 (Wyttenbach).…”

Section: Ecg-triggered Bal-ssfpmentioning

confidence: 99%

Renovascular imaging in the NSF Era

Roditi

Maki

Oliveira

et al. 2009

The detection of the association between nephrogenic systemic fibrosis (NSF), a rare but potentially life‐threatening disease only encountered in patients with severely impaired renal function, and the previous administration of some Gd‐chelates has cast a shadow on the administration of Gd‐chelates in patients with chronic renal failure. So far, contrast‐enhanced MR‐angiography (MRA) was considered the best diagnostic modality in patients with suspected renal disease. This review explores the most appropriate use of renal MRA with a focus on newly developed nonenhanced MRA techniques. Nonenhanced MRA techniques mainly based on SSFP with ECG‐gating allow for acceptable spatial resolution to visualize at least the proximal parts of the renal arteries. In addition functional renal imaging techniques and their current clinical role are critically appreciated. J. Magn. Reson. Imaging 2009;30:1323–1334. © 2009 Wiley‐Liss, Inc.

“…While theoretical predictions suggest that greater improvement in FWHM may be obtained with longer scan times, such lengthening of time may not be appropriate for thoraco-abdominal CE-MRA acquisitions due to respiratory motion. Other factors, such as intrinsic motion of the renal arteries associated with cardiac pulsation and diaphragmatic drift during the breath-hold (39,40), may play an important role in limiting the achievable spatial resolution with CE-MRA, and other motion-compensated renal artery angiographic techniques may need to be evaluated (41)(42)(43)(44).…”

Section: Resolution Considerationsmentioning

confidence: 99%

Direct comparison of sensitivity encoding (SENSE) accelerated and conventional 3D contrast enhanced magnetic resonance angiography (CE‐MRA) of renal arteries: Effect of increasing spatial resolution

Muthupillai

Douglas

Huber

et al. 2009

Purpose: To assess the effect of attaining higher spatial resolution in contrast-enhanced magnetic resonance angiography (MRA) of renal arteries using parallel imaging, sensitivity encoding (SENSE), by comparing the SENSE contrast-enhanced (CE) MRA against a conventional CE-MRA protocol with identical scan times, injection protocol, and other acquisition parameters. Materials and Methods:Numerical simulations and a direct comparison of SENSE-accelerated versus conventional acquisitions were performed. A total of 41 patients (18 male) were imaged using both protocols for a direct comparison. Both protocols used fluoroscopic triggering, centric encoding, breath-holding, equivalent injection protocol, and lasted %30 seconds.Results: Simulated point-spread functions were narrower for the SENSE protocol compared to the conventional protocol. In the patient study, although the SENSE protocol produced images with lower signal-to-noise ratio (SNR), image quality was better for all segments of the renal arteries. In addition, ringing of kidney parenchyma and renal artery blurring were significantly reduced in the SENSE protocol. Finally, reader confidence improved with the SENSE protocol.Conclusion: Despite a reduction in SNR, the higher-resolution SENSE CE-MRA provided improved image quality, reduced artifacts, and increased reader confidence compared to the conventional protocol.