Concentration of Gallbladder Phosphatidylcholine in Cholangiopathies: A Phosphorus‐31 Magnetic Resonance Spectroscopy Pilot Study

Abstract

Background: Biliary phosphatidylcholine (PtdC) concentration plays a role in the pathogenesis of bile duct diseases. In vivo phosphorus-31 magnetic resonance spectroscopy ( 31 P-MRS) at 7 T offers the possibility to assess this concentration noninvasively with high spectral resolution and signal intensity. Purpose: Comparison of PtdC levels of cholangiopathic patient groups to a control group using a measured T 1 relaxation time of PtdC in healthy subjects. Study Type: Case control. Subjects: Two patient groups with primary sclerosing cholangitis (PSC, 2f/3 m; age: 43 AE 7 years) and primary biliary cholangitis (PBC, 4f/2 m; age: 57 AE 6 years), and a healthy control group (CON, 2f/3 m; age: 38 AE 7 years). Ten healthy subjects for the assessment of the T 1 relaxation time of PtdC. Field Strength/Sequence: A 3D phase-encoded pulse-acquire 31 P-MRSI sequence for PtdC quantification and a 1D image-selected in vivo 31 P spectroscopy for T 1 estimation at 7 T, and a T2-weighted half-Fourier single-shot turbo spin echo MRI sequence for volumetry at 3 T. Assessment: Calculation of gallbladder volumes and PtdC concentration in groups using hepatic gamma-adenosine triphosphate signal as an internal reference and correction for insufficient relaxation of PtdC with a T 1 value assessed in healthy subjects. Statistical Tests: Group comparison of PtdC content and gallbladder volumes of the PSC/PBC and CON group using Student's t-tests with a significance level of 5%. Results: PtdC T 1 value of 357 AE 85 msec in the gallbladder. Significant lower PtdC content for the PSC group, and for the female subgroup of the PBC group compared to the CON group (PSC/CON: 5.74 AE 0.73 mM vs. 9.64 AE 0.97 mM, PBC(f)/ CON: 5.77 AE 1.44 mM vs. 9.64 AE 0.97 mM). Significant higher gallbladder volumes of the patient groups compared to the CON group (PSC/CON: 66.3 AE 15.8 mL vs. 20.9 AE 2.2 mL, PBC/CON: 49.8 AE 18.2 mL vs. 20.9 AE 2.2 mL).Data Conclusion: This study demonstrated the application of a 31 P-MRSI protocol for the quantification of PtdC in the human gallbladder at 7 T. Observed differences in PtdC concentration suggest that this metabolite could serve as a biomarker for specific hepatobiliary disorders. Level of Evidence: 2 Technical Efficacy Stage: 3

Bile Composition - which Components Can Have Clinical Significance? A Review of the Literature

“…The authors verified utility of a phosphorus-31 magnetic resonance spectroscopy (31P-MRSI) protocol for the quantification of PtC in the human gallbladder. They demonstrated significantly lower PtC content for the PSC group, and for the female subgroup of the primary biliary cholangitis (PBC) compared to the control group [20]. These results indicate that PtC is an interesting potential biomarker, potentially to be used in some specific benign hepatic and biliary diseases in the future.…”

Mast Cells in Immune-Mediated Cholangitis and Cholangiocarcinoma

“…Both PBC and PSC share similarities such as diagnostic images where obliteration of the bile ducts is easily observed showing a beading pattern and histological findings unveiling both infiltrating cells and collagen fibers deposited around the bile ducts. In addition, PBC and PSC patients present biochemical and tissue architecture modifications in the gallbladder [29,30]. However, these diseases are not fully similar.…”

In Vitro 31P MR Chemical Shifts of In Vivo-Detectable Metabolites at 3T as a Basis Set for a Pilot Evaluation of Skeletal Muscle and Liver 31P Spectra with LCModel Software

“…Very close to the chemical shift of PEP is the chemical shift of phosphatidylcholine (PtdC). It is one of the main compounds in the bile and can decrease in patients with cholangiopathies [46]. PtdC itself is very poorly soluble in water, and therefore, its resonance frequencies were obtained in ethanol-water mixtures (with a Triton−100 surfactant).…”