Saturated multi-delay renal arterial spin labeling technique for simultaneous perfusion and T₁ quantification in...

Area of Science:

• Magnetic Resonance Imaging
• Renal Physiology
• Medical Diagnostics

Background:

• Accurate renal assessment requires simultaneous T1 mapping and perfusion quantification.
• Existing methods are often time-consuming, limiting clinical utility.
• Arterial Spin Labeling (ASL) and T1 mapping are valuable MRI techniques for renal evaluation.

Purpose of the Study:

• To develop a free-breathing, simultaneous multi-delay arterial spin labeling (ASL) and T1 mapping technique for renal assessment.
• To achieve this in a single, time-efficient 4-minute scan at 3 Tesla using a stepwise kinetic model.
• To validate the feasibility and repeatability of the proposed technique.

Main Methods:

• A novel SAturated Multi-delay Renal arterial spin labeling (SAMURAI) sequence was implemented using FAIR preparation and Look-Locker SPGR acquisition.
• Saturation-based T1 mapping was achieved through pre-saturation at the imaging slice.
• A 4-step kinetic model was employed to characterize water transition and correct for ASL signal variations, followed by dictionary-based T1 estimation and model fitting for perfusion quantification.

Main Results:

• The SAMURAI technique demonstrated accurate T1 mapping (R² = 0.98 vs. IR-SE) and reliable ASL/T1 quantification (ICC 0.875-0.958) compared to established methods.
• It successfully detected low renal blood flow and increased T1 in patients with renal diseases.
• The technique achieved excellent scan-rescan repeatability (ICC 0.905-0.992) and significantly reduced scan time (4 min 6 s vs. 45 min).

Conclusions:

• The SAMURAI technique is a feasible and repeatable method for simultaneous renal T1 and perfusion quantification.
• Its high time-efficiency makes it a valuable tool for improved renal assessment.
• This technique offers a significant advancement in rapid, non-invasive kidney MRI.