Utilizing Dynamic Phosphorous-31 Magnetic Resonance Spectroscopy for the Early Detection of Acute Compartment Syndrome: A Pilot Study on Rats

Introduction: Disasters, including terrorism and earthquakes, are significant threats to people and may lead to many people requiring rescue. The longer the rescue takes, the higher the chances of an individual contracting acute compartment syndrome (ACS). ACS is fatal if diagnosed too late, and early diagnosis and treatment are essential. Objective: To assess the ability of dynamic phosphorus magnetic resonance spectroscopy (31P-MRS) in the early detection of muscular damage in ACS. Materials and Methods: Six ACS model rats were used for serial 31P-MRS scanning (9.4 Tesla). Skeletal muscle metabolism, represented by the levels of phosphocreatine (PCr), inorganic phosphate (Pi), and adenosine triphosphate (ATP), was assessed. The PCr/(Pi + PCr) ratio, which decreases with ischemia, was compared with simultaneously sampled plasma creatine phosphokinase (CPK), a muscle damage marker. Results: The PCr/(Pi + PCr) ratio significantly decreased after inducing ischemia (from 0.86 ± 0.10 to 0.18 ± 0.06; p < 0.05), while CPK did not change significantly (from 89 ± 29.46 to 241.50 ± 113.28; p > 0.05). The intracellular and arterial pH index decreased over time, revealing significant differences at 120 min post-ischemia (from 7.09 ± 0.01 to 6.43 ± 0.13, and from 7.47 ± 0.03 to 7.39 ± 0.04, respectively). In the reperfusion state, the spectra and pH did not return to the original values. Conclusions: The dynamic 31P-MRS technique can rapidly detect changes in muscle bioenergetics. This technique is a promising non-invasive method for determining early muscular damage in ACS.

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An Early Detection of Acute Compartment Syndrome in Fastened Zip-Tie Rat Model Using Dynamic Phosphorous-31 Magnetic Resonance Spectroscopy at 9.4 Tesla

10.21203/rs.3.rs-143667/v1 ◽

2021 ◽

Author(s):

Hiroki Ohta ◽

Nhat-Minh Van Vo ◽

Junichi Hata ◽

Koshiro Terawaki ◽

Takako Shirakawa ◽

...

Keyword(s):

Magnetic Resonance ◽

Early Detection ◽

Magnetic Resonance Spectroscopy ◽

Compartment Syndrome ◽

Rat Model ◽

Resonance Spectroscopy ◽

Non Invasive ◽

Arterial Ph ◽

Invasive Method ◽

Muscular Damage

Abstract IntroductionAcute compartment syndrome (ACS) leads to a series of health problems, limb salvage, disability, and even death. In vivo phosphorus-31 magnetic resonance spectroscopy (31P-MRS) provides a unique non-invasive method to assess skeletal muscle metabolisms such as inorganic phosphate (Pi), phosphocreatine (PCr), and adenosine triphosphate (ATP). The study aims to assess the ability of dynamic 31P-MRS in the early detection of muscular damage in ACS.Materials & MethodsThe study induced the fastened zip-tie model of ACS on normotensive Sprague-Dawley rats (n = 6). The spectra were acquired in Bruker 9.4-Tesla preclinical scanner using 1H/31P surface coil. 31P-MRS spectra and blood samples were obtained at time 0 (pre-ischemic phase) and every 15 minutes during the compression (120 minutes) and the reperfusion phase (90 minutes). 31P-MRS spectra findings were compared with plasma creatine phosphokinase (CPK).ResultsPCr/(Pi + PCr) ratio significantly decreased after muscle was compressed (P < 0.05). In contrast to this, CPK did not change significantly (P > 0.05). Both intracellular pH and arterial pH decreased over time. However, intracellular declined significantly (P < 0.05) at 60 minutes of ischemic state, and at 5 minutes and 60 minutes of reperfusion, while arterial pH slightly changed. After 30 minutes of ischemic, phosphomonoesters (PME) peak was detected, which was not seen at the pre-ischemic phase. It gradually increased and reached its highest peak at 120 minutes. At reperfusion state, 31P-MRS spectra and pH did not fully recover to their pre-ischemic state, and PME peak disappeared. There was a correlation between T2-weighted images and CPK from blood tests (R2 = 0.1996, P < 0.05).ConclusionsDynamic 31P-MRS technique is more clearly and rapidly detect the bioenergetic and mitochondrial functions change than blood test in a fastened zip-tie rat model of ACS. This technique is a promising non-invasive method to detect the early ischemic muscular damage in ACS.

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Phosphorus magnetic resonance spectroscopy and imaging (31P-MRS/MRSI) as a window to brain and muscle metabolism: A review of the methods

Biomedical Signal Processing and Control ◽

10.1016/j.bspc.2020.101967 ◽

2020 ◽

Vol 60 ◽

pp. 101967 ◽

Cited By ~ 1

Author(s):

Alejandro Santos-Díaz ◽

Michael D. Noseworthy

Keyword(s):

Magnetic Resonance ◽

Magnetic Resonance Spectroscopy ◽

Muscle Metabolism ◽

Resonance Spectroscopy ◽

Phosphorus Magnetic Resonance Spectroscopy ◽

31P Mrs

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Phosphorous Magnetic Resonance Spectroscopy to Detect Regional Differences of Energy and Membrane Metabolism in Naïve Glioblastoma Multiforme

Cancers ◽

10.3390/cancers13112598 ◽

2021 ◽

Vol 13 (11) ◽

pp. 2598

Author(s):

Lisa Maria Walchhofer ◽

Ruth Steiger ◽

Andreas Rietzler ◽

Johannes Kerschbaumer ◽

Christian Franz Freyschlag ◽

...

Keyword(s):

Glioblastoma Multiforme ◽

Magnetic Resonance ◽

Magnetic Resonance Spectroscopy ◽

Healthy Volunteers ◽

Regional Differences ◽

Primary Brain Tumor ◽

Brain Parenchyma ◽

Resonance Spectroscopy ◽

31P Mrs ◽

Diffusion Parameters

Background: Glioblastoma multiforme (GBM) is a highly malignant primary brain tumor with infiltration of, on conventional imaging, normal-appearing brain parenchyma. Phosphorus magnetic resonance spectroscopy (31P-MRS) enables the investigation of different energy and membrane metabolites. The aim of this study is to investigate regional differences of 31P-metabolites in GBM brains. Methods: In this study, we investigated 32 patients (13 female and 19 male; mean age 63 years) with naïve GBM using 31P-MRS and conventional MRI. Contrast-enhancing (CE), T2-hyperintense, adjacent and distant ipsilateral areas of the contralateral brain and the brains of age- and gender-matched healthy volunteers were assessed. Moreover, the 31P-MRS results were correlated with quantitative diffusion parameters. Results: Several metabolite ratios between the energy-dependent metabolites and/or the membrane metabolites differed significantly between the CE areas, the T2-hyperintense areas, the more distant areas, and even the brains of healthy volunteers. pH values and Mg2+ concentrations were highest in visible tumor areas and decreased with distance from them. These results are in accordance with the literature and correlated with quantitative diffusion parameters. Conclusions: This pilot study shows that 31P-MRS is feasible to show regional differences of energy and membrane metabolism in brains with naïve GBM, particularly between the different “normal-appearing” regions and between the contralateral hemisphere and healthy controls. Differences between various genetic mutations or clinical applicability for follow-up monitoring have to be assessed in a larger cohort.

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