Three-dimensional static-fluid MR urography with gradient- and spin-echo (GRASE) at 3.0T: comparison of image quality and diagnostic performance with respiratory-triggered fast spin-echo (FSE)

Wei Wang,Jianxing Qiu,Jing Liu,Wei Li,Junzhe Yang,Kai Zhao,Yongming Dai,Ke Xue

doi:10.1007/s00261-022-03418-3

Abstract

PurposeTo compare the performance of 3D MRU based on a breath-hold gradient- and spin-echo (BH-GRASE) technique with conventional 3D respiratory-triggered FSE (RT-FSE) sequence in patients with urinary tract dilation.MethodsWe prospectively included 90 patients with urinary tract dilation who underwent both 3D BH-GRASE and RT-FSE MRU at 3T. The acquisition time of two MRU sequences was recorded. Three readers blinded to the protocols reviewed the image quality using a five-point scale and assessed the diagnostic performance related to urinary tract dilation. The relative contrast ratio (CR) between the urinary tract and adjacent area was measured quantitatively.ResultsAcquisition time was 14.8 s for BH-GRASE MRU and 213.6 ± 52.2 s for RT-FSE MRU. The qualitative image analysis demonstrated significant equivalence between the two MRU protocols. 3D BH-GRASE MRU better depicted bilateral renal calyces than RT-FSE MRU (p < 0.05). The CR values of the urinary tract were lower on BH-GRASE MRU compared with RT-FSE MRU (p < 0.05). There were excellent agreements in the assessment of urinary tract dilation between BH-GRASE and RT-FSE MRU, including the dilated degree, obstructive level, and obstructive imaging features (inter-sequence κ = 0.924–1).Conclusion3D BH-GRASE MRU significantly decreased the acquisition time and achieved comparable image quality, urinary tract visualization, and diagnostic performance with conventional 3D RT-FSE MRU. Breath-hold 3D MRU with GRASE may provide a feasible evaluation of urinary tract dilation.Graphical abstract

Highlights

A comprehensive “one-stop-shop” of multi-parametric magnetic resonance urography (MRU) protocol should include basic sequences covering the upper collecting system to the bladder, and other complement sequences such as a heavily T2-weighted cholangiopancreatography (MRCP)-like imaging [1–3]
Compared with conventional excretory MRU or CTU, static-fluid MRU does not depend on the excretion of contrast medium, and it is suitable for patients with poorly excreting, dilated urinary tract [4]
All MRU examinations were performed on a 3T MR scanner using two pieces of 12-channel body matrix coil combined with a 32-channel spine matrix coil

Summary

Introduction

A comprehensive “one-stop-shop” of multi-parametric magnetic resonance urography (MRU) protocol should include basic sequences covering the upper collecting system to the bladder, and other complement sequences such as a heavily T2-weighted cholangiopancreatography (MRCP)-like imaging [1–3]. The latter, which is called static-fluid MRU, is clinically useful for quickly and directly identifying the urinary tract dilation and obstructive level [3]. Compared with conventional excretory MRU or CTU, static-fluid MRU does not depend on the excretion of contrast medium, and it is suitable for patients with poorly excreting, dilated urinary tract [4]. The T2WI MRU can be routinely obtained in twodimensional (2D) with the breath-hold thick-slab singleshot fast spin-echo or similar thin-section techniques

Methods

Results

Conclusion