MRI: Evaluating the Application of FOCUS‐MUSE Diffusion‐Weighted Imaging in the Pancreas in Comparison With FOCUS, MUSE, and Single‐Shot DWIs

Abstract

Background Diffusion‐weighted imaging (DWI) is a useful technique to detect pancreatic lesion. In DWIs, field‐of‐view optimized and constrained undistorted single‐shot (FOCUS) can improve the spatial resolution and multiplexed sensitivity‐encoding (MUSE) can gain a high signal‐to‐noise ratio (SNR). Based on the advantage of FOCUS and MUSE, a new DWI sequence—named FOCUS‐MUSE DWI (FOCUS combined with MUSE)—was developed to delineate the pancreas. Purpose To investigate the reliability of FOCUS‐MUSE DWI compared to FOCUS, MUSE and single‐shot (SS) DWI via the systematical evaluation of the apparent diffusion coefficient (ADC) measurements, SNR and image quality. Study Type Prospective. Subjects A total of 33 healthy volunteers and 9 patients with pancreatic lesion. Field Strength/Sequence A 3.0 T scanner. FOCUS‐MUSE DWI, FOCUS DWI, MUSE DWI, SS DWI. Assessment For volunteers, ADC and SNR were measured by two readers in the pancreatic head, body, and tail. For all subjects, the diagnostic image quality score was assessed by three other readers on above four DWIs. Statistical Tests Paired‐sample T‐test, intraclass correlation (ICC), Bland–Altman method, Friedman test, Dunn‐Bonferroni post hoc test and kappa coefficient. A significance level of 0.05 was used. Results FOCUS‐MUSE DWI had the best intersession repeatability of ADC measurements (head: 59.53, body: 101.64, tail: 42.30) among the four DWIs, and also maintained the significantly highest SNR (reader 1 [head: 19.68 ± 3.23, body: 23.42 ± 5.00, tail: 28.85 ± 4.96], reader 2 [head: 19.93 ± 3.52, body: 23.02 ± 5.69, tail: 29.77 ± 6.33]) except for MUSE DWI. Furthermore, it significantly achieved better image quality in volunteers (median value: 4 score) and 9 patients (most in 4 score). Data Conclusion FOCUS‐MUSE DWI improved the reliability of pancreatic images with the most stable ADC measurement, best image quality score and sufficient SNR among four DWIs. Evidence Level 2 Technical Efficacy Stage 2

Synthetic high b-value FOCUS-MUSE diffusion-weighted imaging in identifying early-stage cervical cancer

“…Therefore, lesion conspicuity is particularly important for assessing the in ltration of CC in the parauterine organ. A study of pancreatic cancer has reported the superior subjective assessment and inter-observer ADC measurements using FOCUS-MUSE DWI compared to MUSE DWI and FOCUS DWI while inferior SNR using FOCUS-MUSE DWI to MUSE DWI [9]. Consistently, syFOCUS-MUSE 13b/5b,1500 in particular syOCUS-MUSE 5b,1500 with the best inter-reader consistency of lesion conspicuity and anatomical details may elevate subjective diagnosis of CC stage.…”

“…The reduced eld-of-view single-shot and multi-shot DWIs may reduce magnetic sensitivity and motion artifacts as well as increase image resolution [9,10]. A reduced eld-of-view single-shot DWI sequence is used via simultaneously 2D spatially-selective radio frequency pulse (2D RF) and 180° refocusing pulse suppressed [6,11], while a multi-shot DWI sequence is performed through at least two separate RF excitations followed by alternative k-space ll-in [9,12]. Applications of FOCUS-DWI, MUSE DWI and FOCUS-MUSE DWI have reported good image quality and diagnostic e cacy on pancreas [9], breast [10], uterus [13], prostate [14].…”

“…A reduced eld-of-view single-shot DWI sequence is used via simultaneously 2D spatially-selective radio frequency pulse (2D RF) and 180° refocusing pulse suppressed [6,11], while a multi-shot DWI sequence is performed through at least two separate RF excitations followed by alternative k-space ll-in [9,12]. Applications of FOCUS-DWI, MUSE DWI and FOCUS-MUSE DWI have reported good image quality and diagnostic e cacy on pancreas [9], breast [10], uterus [13], prostate [14]. MUSE DWI has better image quality than FOCUS DWI and nearly equivalent diagnostic performance to DCE-MRI in assessing super cial and deep myographic in ltration of EC (endometrial cancer) [13].…”

Evaluation of Whole Brain Intravoxel Incoherent Motion (IVIM) Imaging

“…Considering the IVIM protocol to be as quick as possible, the scanning duration was limited to 15 min. A MUSE sequence was used to ensure the maximum available SNR level [ 15 ]. While planning an experiment, we tried selecting b -values that were accessible on the scanner and were close to an optimized set [ 16 ].…”

Evaluation of Whole Brain Intra Voxel Incoherent Motion (IVIM) Imaging

“…Considering this protocol to be as quick as possible, scanning duration was set with a maximum limit of 15 minutes. To ensure maximum available SNR level a MUSE sequence was used [14]. While planning an experiment we tried selecting b-values accessible on the scanner, close to an optimized set [15].…”