Patient respiratory‐triggered quantitative T₂ mapping in the pancreas

Abstract

Background Long acquisition times and motion sensitivity limit T2 mapping in the abdomen. Accelerated mapping at 3 T may allow for quantitative assessment of diffuse pancreatic disease in patients during free‐breathing. Purpose To test the feasibility of respiratory‐triggered quantitative T2 analysis in the pancreas and correlate T2‐values with age, body mass index, pancreatic location, main pancreatic duct dilatation, and underlying pathology. Study Type Retrospective single‐center pilot study. Population Eighty‐eight adults. Field Strength/Sequence Ten‐fold accelerated multiecho‐spin‐echo 3 T MRI sequence to quantify T2 at 3 T. Assessment Two radiologists independently delineated three regions of interest inside the pancreatic head, body, and tail for each acquisition. Means and standard deviations for T2 values in these regions were determined. T2‐value variation with demographic data, intraparenchymal location, pancreatic duct dilation, and underlying pancreatic disease was assessed. Statistical Tests Interreader reliability was determined by calculating the interclass coefficient (ICCs). T2 values were compared for different pancreatic locations by analysis of variance (ANOVA). Interpatient associations between T2 values and demographical, clinical, and radiological data were calculated (ANOVA). Results The accelerated T2 mapping sequence was successfully performed in all participants (mean acquisition time, 2:48 ± 0:43 min). Low T2 value variability was observed across all patients (intersubject) (head: 60.2 ± 8.3 msec, body: 63.9 ± 11.5 msec, tail: 66.8 ± 16.4 msec). Interreader agreement was good (ICC, 0.82, 95% confidence interval: 0.77–0.86). T2‐values differed significantly depending on age (P < 0.001), location (P < 0.001), main pancreatic duct dilatation (P < 0.001), and diffuse pancreatic disease (P < 0.03). Data Conclusion The feasibility of accelerated T2 mapping at 3 T in moving abdominal organs was demonstrated in the pancreas, since T2 values were stable and reproducible. In the pancreatic parenchyma, T2‐values were significantly dependent on demographic and clinical parameters. Level of Evidence: 4 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;50:410–416.

Multiparametric Mapping Magnetic Resonance Imaging of Pancreatic Disease

“…T1 and T2 relaxation times are valuable as quantitative parameters to characterize different tissues, especially in myocardial and liver diseases (Apprich et al, 2012;Kali et al, 2015;Blystad et al, 2017;Chen et al, 2017;Vietti Violi et al, 2019). T1 mapping was shown to improve the diagnosis of myocarditis, infarction, iron overload, and amyloidosis (Guo et al, 2009;Karamitsos et al, 2013;Kali et al, 2015).…”

Magnetic resonance fingerprinting of the pancreas at 1.5 T and 3.0 T

“…The MRF framework allows qualitative and quantitative data to be acquired simultaneously, allowing ready comparison between longitudinal time points and against population-derived norms, as well as giving improved imaging repeatability and more meaningful interpretation of intensity changes. The total acquisition time was very low when compared with other reported single parameter acquisitions (non-MRF based), which include quantitative T 2 measurements of the pancreas at 1.5 T: 8 min 16 and 3 T: 2 min 50 s 9 . Similar to Wang 35 , T 1 maps with MRF were obtained in 10 s/slice, although we did Figure 3.…”

“…Endoscopic ultrasonography (EUS) is the most sensible imaging method for the pancreas 3,4 , but it is invasive, operator dependent and associated with complications. T 1 and T 2 relaxation times are valuable quantitative parameters to characterize different tissues, particularly in the assessment of myocardial and liver diseases [5][6][7][8][9] . Thus far only some studies have reported on the value of quantitative MRI on the pancreas.…”

“…This subjective evaluation is highly parameter dependent, which reduces the ability for analysis to be translated across centres. Quantitative analysis is mostly undertaken in a research context, often limited to conventional methods, due to the significant scan time required and technical limitations such as field inhomogeneities and patient motion 9,16 .…”

Quantitative brain relaxation atlases for personalized detection and characterization of brain pathology

“…In consequence, this would prolong the scan time far beyond what is clinically acceptable, compromising the applicability of our approach. In addition, the proposed T 2 mapping strategy has been proved to deliver maps in agreement with conventional techniques and with excellent reproducibility, as well as good sensitivity toward T 2 alterations caused by pathologies . Lastly, it should be noted that fitting errors leading to an inaccurate estimation of T 1 and T 2 values were not discussed here, because these can be found in the original publications …”