Liver MR relaxometry at 3T – segmental normal T1 and T2* values in patients without focal or diffuse liver disease and in patients with increased liver fat and elevated liver stiffness

Abstract

Magnetic resonance (MR) T 1 and T 2 * mapping allows quantification of liver relaxation times for non-invasive characterization of diffuse liver disease. We hypothesized that liver relaxation times are not only influenced by liver fibrosis, inflammation and fat, but also by air in liver segments adjacent to the lung – especially in MR imaging at 3T. A total of 161 study participants were recruited, while 6 patients had to be excluded due to claustrophobia or technically uninterpretable MR elastography. Resulting study population consisted of 12 healthy volunteers and 143 patients who prospectively underwent multiparametric MR imaging at 3T. Of those 143 patients, 79 had normal liver stiffness in MR elastography (shear modulus <2.8 kPa, indicating absence of fibrosis) and normal proton density fat fraction (PDFF < 10%, indicating absence of steatosis), defined as reference population. T 1 relaxation times in these patients were significantly shorter in liver segments adjacent to the lung than in those not adjacent to the lung (p < 0.001, mean of differences 33 ms). In liver segments not adjacent to the lung, T 1 allowed to differentiate significantly between the reference population and patients with steatosis and/or fibrosis (p ≤ 0.011), while there was no significant difference of T 1 between the reference population and healthy volunteers. In conclusion, we propose to measure T 1 relaxation times in liver segments not adjacent to the lung. Otherwise, we recommend taking into account slightly shorter T 1 values in liver segments adjacent to the lung.

Non-Invasive Characterization of Liver Disease : By Multimodal Quantitative Magnetic Resonance

“…One common sequence is the MOLLI sequence [93]. Like the method in Paper II, MOLLI is also a method for accelerating an IR experiment, and a 2D slice of the liver can be acquired in a single breath hold [94,95]. Moreover, there are also IR methods that quantify liver T1 in multiple slices during free breathing acquisition [96].…”

Simultaneous proton density fat‐fraction and imaging with water‐specific T1 mapping (PROFIT1): application in liver

“…These results, in agreement with previous studies showing large T 1 errors for the steady-state free-precession T 1 mapping methods, 16,18 strongly suggest that these methods are not appropriate for T 1 mapping when fat is present, as is common in the liver. Increased liver T 1 values measured with the MOLLI method have been reported in those with liver disease with steatosis, 35 but it is likely that T 1 values are strongly influenced by the PDFF, which complicates interpretation of the T 1 values. Similar large systematic T 1 errors for mix fat-water systems were also illustrated for the spoiled gradient-echo acquisition in the current study.…”

Multiparametric MR mapping in clinical decision-making for diffuse liver disease

“…Multiparametric MRI refers to use of multiple quantitative (parametric) MRI features or measures with several possibilities for combinations [34][35][36][40][41][42][43][44][45]. Therefore, these combinations could be used to evaluate two or more specific characteristics of chronic liver disease and diffuse liver processes, to include derivation of composite metrics [44,46].…”

“…≥ G1: 0.93 [85] ≥ G2: 0.96 [85] ≥ G3: 0.94 [85] Not applicable but can add PDFF [36,40] Diagnosis of fibrosis Not applicable but can combine with T1 or DWI or MRE [35,41,45,89] cT1 AUROC for fibrosis stages: 11.0% [88] Confounded by iron…”