Separation of advanced from mild fibrosis in diffuse liver disease using 31P magnetic resonance spectroscopy

³¹P-MRS using DRESS was used to compare absolute liver metabolite concentrations (PME, Pi, PDE, γATP, ATP, βATP) in two distinct groups of patients with chronic diffuse liver disorders, one group with steatosis (NAFLD) and none to moderate inflammation (n = 13), and one group with severe fibrosis or cirrhosis (n = 16). All patients underwent liver biopsy and extensive biochemical evaluation. A control group (n = 13) was also included. Absolute concentrations and the anabolic charge, AC = {PME}/({PME} + {PDE}), were calculated.

Comparing the control and cirrhosis groups, lower concentrations of PDE (p = 0.025) and a higher AC (p < 0.001) were found in the cirrhosis group. Also compared to the NAFLD group, the cirrhosis group had lower concentrations of PDE (p = 0.01) and a higher AC (p = 0.009). No significant differences were found between the control and NAFLD group. When the MRS findings were related to the fibrosis stage obtained at biopsy, there were significant differences in PDE between stage F0–1 and stage F4 and in AC between stage F0–1 and stage F2–3.

Using a PDE concentration of 10.5 mM as a cut-off value to discriminate between mild, F0–2, and advanced, F3–4, fibrosis the sensitivity and specificity were 81% and 69%, respectively. An AC cut-off value of 0.27 showed a sensitivity of 93% and a specificity of 54%.

In conclusion, the results suggest that PDE is a marker of liver fibrosis, and that AC is a potentially clinically useful parameter in discriminating mild fibrosis from advanced.     

Influence of different fasting periods on P-31-MR-spectroscopy of the liver in normals and patients with liver metastases

The purpose of this study was to determine the influence of different fasting periods on the in vivo P-31-MR spectroscopy of the healthy liver and patients with liver metastases. Image-guided localized P-31-MRS was performed in 24 patients with liver metastases and in 20 healthy volunteers. The spectra were obtained with a whole body scanner operating at 1.5 T using a surface coil. The P-31-MRS was performed after a fasting period of 3–5 h (group 1) and after overnight fasting (group 2). The PME/-NTP, PDE/-NTP and Pi/-NTP were calculated from P-31-MR spectra and were compared in relation to the nutrition status of the volunteers and patients. The PME/-NTP and PDE/-NTP were significantly increased in spectra of patients with metastases. There were no significant changes in the ratios of phosphorus metabolites in healthy liver tissue or in liver metastases after a fasting period of 3–5 h as compared with overnight fasting.     

Assessment of functional severity on in vivo hepatic 31P-MRS in diffuse hepatic disease: comparative studies with 99mTc-GSA

The purpose of this study was to compare the assessment of functional severity on in-vivo hepatic 31P-MRS in diffuse hepatic disease with functional severity assessed with 99mTc galactosyl serum albumin (99mTc-GSA). 31P-MRS was performed in 10 healthy control subjects and 16 patients with diffuse hepatic disease. Data were expressed as peak area ratios: PME/beta-ATP, PDE/beta-ATP, PME/PDE, Pi/beta-ATP, and PME/Pi. The functional severity of hepatic damage was evaluated visually and quantitatively (HH15, LHL15) by 99mTc-GSA in the group of patients with diffuse hepatic disease. Visual evaluation was classified into four grades based on anterior images of cardiac blood-pool and liver. We studied the correlation of spectral metabolic ratios and functional severity by 99mTc-GSA. We found statistically significant differences (ANOVA) among the classifications of Grade I, Grade II, and Grade III with both PME/beta-ATP and PME/PDE. A statistically significant direct correlation was found between HH15 and both PME/beta-ATP and PME/PDE. A significant inverse correlation was also seen between LHL15 and both PME/beta-ATP and PME/PDE. The studies comparing 31P-MRS with functional severity assessed by 99mTc-GSA showed that PME/beta-ATP and PME/PDE were useful for the assessment of functional severity in patients with diffuse hepatic disease.     

Hepatic cancers and their response to chemoembolization therapy. Quantitative image-guided 31P magnetic resonance spectroscopy.

RATIONALE AND OBJECTIVES. Hepatic embolization combined with intra-arterial administration of cytostatic drugs (chemoembolization) is frequently used to treat primary and metastatic cancers to the liver. Quantitative phosphorus-31 magnetic resonance spectroscopy (31P MRS) was used to assess the metabolic state of hepatic cancers and their metabolic response to chemoembolization. METHODS. Fifteen localized 31P MRS studies were performed on five patients with liver tumors. Thirteen healthy volunteers served as controls. Metabolite ratios and molar metabolite concentrations were calculated. RESULTS. Untreated hepatic tumors, relative to normal controls, showed elevated phosphomonoester/adenosine triphosphate (PME/ATP) ratios, reduced concentrations of ATP and inorganic phosphate (Pi), and normal phosphodiester (PDE) concentrations. As an acute response to chemoembolization, ATP, PME, and/or PDE concentrations diminished, whereas Pi concentrations increased or stayed relatively constant. Long-term follow-up after chemoembolization showed decreased PME/ATP and increased ATP concentrations in the absence of changes on standard magnetic resonance and computed tomographic images. CONCLUSIONS. These preliminary spectroscopic data suggest that quantitative 31P MRS can be successfully used to monitor directly metabolic response to hepatic chemoembolization.     

Decreased phosphorus metabolite concentrations and alkalosis in chronic cerebral infarction.

A study was performed to determine quantitatively the alterations in phosphorus metabolite concentrations and pH in regions of the human brain damaged by chronic stroke. Image-guided phosphorus-31 magnetic resonance spectroscopy was performed on the brains of eight healthy subjects and six patients with cerebral infarction of more than 3 months duration. Phosphorus metabolite concentrations in infarcted regions were reduced 8%-67%. Significant decreases occurred in phosphomonoester (PME), phosphodiester (PDE), and adenosine triphosphate (ATP) concentrations, while inorganic phosphate (Pi) and phosphocreatine (PCr) concentrations showed smaller, nonsignificant decreases. The PCr/ATP ratio was significantly increased, while the ATP/Pi ratio was somewhat lower. The phospholipid ratio PDE/PME was also significantly increased, while the ratios of phospholipid (PME, PDE) to phosphate (PCR, Pi) metabolites were significantly decreased. The pH of the infarcted region indicated significantly more alkalinity than in the normal brain. The results suggest that chronic stroke is associated with significant changes in brain metabolite concentrations and pH that are different from those reported for other brain diseases.     

Non-invasive determination of metabolite concentrations in human transplanted kidney in vivo by 31P MR spectroscopy

PURPOSE: To investigate concentrations of phosphorus-containing metabolites in human transplanted kidney in vivo by quantitative 31P MR spectroscopy (MRS) using surface coils and to compare the obtained values with previous data. MATERIAL AND METHODS: In 5 patients with well-functioning transplanted kidneys, 31P spectra were obtained with the three-dimensional localization image-selected in vivo spectroscopy technique applying a protocol for quantitative spectroscopy using surface coils. Relaxation corrected signal intensities determined by time domain fitting were used to derive absolute molar concentrations for phosphate-containing metabolites. RESULTS: Little or no phosphocreatine in all spectra verified the absence of muscle contamination, confirming proper volume localization. The mean concentrations in the transplanted kidneys were as follows: ATP 1.60 +/- 0.26 mmol/ 1, PDE 2.14 +/- 0.91 mmol/l, Pi 0.66 +/- 0.25 mmol/l, PME 2.32+ /- 0.50 mmol/l. These values are consistent with previously reported values determined by other techniques. CONCLUSION: The non-invasive determination of absolute metabolite concentrations in human kidney using MRS supplements the use of signal intensity ratios to detect pathologic changes in the energy metabolism of transplanted kidneys.     

Wilson’s disease: 31P and 1H MR spectroscopy and clinical correlation

Introduction

Proton (¹H) magnetic resonance spectroscopy (MRS) changes are noted in Wilson’s disease (WD). However, there are no studies regarding membrane phospholipid abnormality using ³¹P MRS in these patients. We aimed to analyze the striatal spectroscopic abnormalities using ³¹P and ¹H MRS in WD.

Methods

Forty patients of WD (treated, 29; untreated,11) and 30 controls underwent routine MR image sequences and in vivo 2-D ³¹P and ¹H MRS of basal ganglia using an image-selected technique on a 1.5-T MRI scanner. Statistical analysis was done using Student’s t test.

Results

The mean durations of illness and treatment were 6.2?±?7.4 and 4.8?±?5.9 years, respectively. MRI images were abnormal in all the patients. ¹H MRS revealed statistically significant reduction of N-acetyl aspartate (NAA)/choline (Cho) and NAA/creatine ratios in striatum (¹H MRS) of treated patients compared to controls. The mean values of phosphomonoesters (PME) (p?<?0.0001), phosphodiesters (PDE) (p?<?0.0001), and total phosphorus (TPh) (p?<?0.0001) were elevated in patients compared to controls. Statistically significant elevated levels of ratio of PME/PDE (p?=?0.05) observed in the striatum were noted in treated patients as compared to controls in the ³¹P MRS study. The duration of illness correlated well with increased PME/PDE [p?<?0.001], PME/TPh [p?<?0.05], and PDE/TPh [p?<?0.05] and decreased NAA/Cho [p?<?0.05] ratios. There was correlation of MRI score and reduced NAA/Cho ratio with disease severity. The PME/PDE ratio (right) was elevated in the treated group [p?<?0.001] compared to untreated group.

Conclusions

There is reduced breakdown and/or increased synthesis of membrane phospholipids and increased neuronal damage in basal ganglia in patients with WD.     

Metabolic profile of liver damage in non-cirrhotic virus C and autoimmune hepatitis: A proton decoupled 31P-MRS study

PurposeTo study liver ³¹P MRS, histology, transient elastography, and liver function tests in patients with virus C hepatitis (HCV) or autoimmune hepatitis (AIH) to test the hypothesis that ³¹P MR metabolic profile of these diseases differ.Materials and methods25 patients with HCV (n = 12) or AIH (n = 13) underwent proton decoupled ³¹P MRS spectroscopy performed on a 3.0 T MR imager. Intensities of phosphomonoesters (PME) of phosphoethanolamine (PE) and phosphocholine (PC), phosphodiesters (PDE) of glycerophosphoethanolamine (GPE) and glycerophosphocholine (GPC), and γ, α and β resonances of adenosine triphosphate (ATP), and nicotinamide adenine dinucleotide phosphate (NADPH) were determined. Liver stiffness was measured by transient elastography. Inflammation and fibrosis were staged according to METAVIR from biopsy samples. Activities of alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALT) and thromboplastin time (TT) were determined from serum samples.ResultsPME had a stronger correlation with AST (z = 1.73, p = 0.04) and ALT (z = 1.77, p = 0.04) in HCV than in AIH patients. PME, PME/PDE, PE/GPE correlated positively and PDE negatively with inflammatory activity. PE, PC and PME correlated positively with liver function tests.Conclusion³¹P-MRS suggests a more serious liver damage in HCV than in AIH with similar histopathological findings. ³¹P-MRS is more sensitive in detecting inflammation than fibrosis in the liver.     

Noninvasive measurements of cardiac high-energy phosphate metabolites in dilated cardiomyopathy by using 31P spectroscopic chemical shift imaging

Dilated cardiomyopathy (DCM) is accompanied by an impaired cardiac energy metabolism. The aim of this study was to investigate metabolic ratios in patients with DCM compared to controls by using spectroscopic two-dimensional chemical shift imaging (2D-CSI). Twenty volunteers and 15 patients with severe symptoms (left ventricular ejection fraction, LVEF<30%) and ten patients with moderate symptoms (LVEF>30%) of DCM were investigated. Cardiac ³¹P MR 2D-CSI measurements (voxel size: 40×40×100 mm³) were performed with a 1.5 T whole-body scanner. Measurement time ranged from 15 min to 30 min. Peak areas and ratios of different metabolites were evaluated, including high-energy phosphates (PCr, ATP), 2,3-diphosphoglycerate (2,3-DPG) and phosphodiesters (PDE). In addition, we evaluated how PCr/ATP ratios correlate with LVEF as an established prognostic factor of heart failure. The PCr/-ATP ratio was significantly decreased in patients with moderate and severe DCM and showed a linear correlation with reduced LVEFs. PDE/ATP ratios were significantly increased only in patients with severe DCM as compared to volunteers. Applying ³¹P MRS with commonly-available 2D-CSI sequences is a valuable technique to evaluate DCM by determining PCr/ATP ratios noninvasively. In addition to reduced PCr/ATP ratios observed in patients suffering from DCM, significantly-increased PDE/ATP ratios were found in patients with severe DCM.     

A comparison of MR elastography and 31P MR spectroscopy with histological staging of liver fibrosis

Objectives

Conventional imaging techniques are insensitive to liver fibrosis. This study assesses the diagnostic accuracy of MR elastography (MRE) stiffness values and the ratio of phosphomonoesters (PME)/phosphodiesters (PDE) measured using ³¹P spectroscopy against histological fibrosis staging.

Methods

The local research ethics committee approved this prospective, blinded study. A total of 77 consecutive patients (55 male, aged 49 ± 11.5 years) with a clinical suspicion of liver fibrosis underwent an MR examination with a liver biopsy later the same day. Patients underwent MRE and ³¹P spectroscopy on a 1.5 T whole body system. The liver biopsies were staged using an Ishak score for chronic hepatitis or a modified NAS fibrosis score for fatty liver disease.

Results

MRE increased with and was positively associated with fibrosis stage (Spearman’s rank = 0.622, P < 0.001). PME/PDE was not associated with fibrosis stage (Spearman’s rank = −0.041, p = 0.741). Area under receiver operating curves for MRE stiffness values were high (range 0.75–0.97). The diagnostic utility of PME/PDE was no better than chance (range 0.44–0.58).

Conclusions

MRE-estimated liver stiffness increases with fibrosis stage and is able to dichotomise fibrosis stage groupings. We did not find a relationship between ³¹P MR spectroscopy and fibrosis stage.

Key Points

• Magnetic resonance elastography (MRE) and MR spectroscopy can both assess the liver.

• MRE is superior to ³¹ P MR spectroscopy in staging hepatic fibrosis.

• MRE is able to dichotomise liver fibrosis stage groupings.

• Gradient-echo MRE may be problematic in genetic haemochromatosis.

     

Assessment of absolute metabolite concentrations in human tissue by 31P MRS in vivo. Part II: Muscle,liver, kidney

Absolute metabolite concentrations were assessed in the muscle, the liver, and the kidney of healthy human volunteers by ³¹P MRS. Fully relaxed in vivo spectra were acquired with a surface coil and were localized with an adiabatic lSlS pulse sequence. The spectra were quantified with a subsequent measurement of a calibration phantom and were processed iteratively in the time domain. The following mean metabolite concentrations (mmollliter) were measured in the resting male calf muscle (n = 9), in the fasting liver (n = 12), and in the orthiotopic kidney (n= 5): [PME] = 2.0 ± 0.6, 3.8 ± 0.7, and 2.6 ± 0.9, [Pi] = 2.9 ± 0.3, 1.8 ± 0.3, and 1.6 ± 0.4, [PDE] = 3.8 ± 0.8, 9.7 ± 1.5, and 4.9 ± 1.1, [PCr] = 22.0 ± 1.2, 0, and 0, [NTP] = 5.7 ± 0.4, 2.9 ± 0.4, and 2.0 ± 0.3, respectively. Several interesting findings are to be emphasized: The concentrations of Pi, PCr, and NTP were 20% lower in the muscle of women than of men. In addition, the pH, was significantly lower in female muscle (6.99 ± 0.03) than in male muscle (7.05 ± 0.03). The pH, in the liver (7.12 ± 0.09) and in the kidney (7.09 ± 0.08) were higher than in the muscle of both genders. The free magnesium concentration (mmollliter) was higher in the lliver (1.40 ± 0.64) than in the kidney (0.79 ± 0.39) and in the muscle (0.52 ± 0.10).     

Liver metastases on quantitative color mapping of the arterial enhancement fraction from multiphasic CT scans: evaluation of the hemodynamic features and correlation with the chemotherapy response

Purpose

To demonstrate the hemodynamic features of liver metastases using quantitative color mapping of the arterial enhancement fraction (AEF) and to investigate the feasibility of using the AEF to predict the chemotherapy response.

Materials and methods

Seventy-two patients with liver metastases (metastasis group) and 18 cancer-matched patients without liver metastases (non-metastasis group) were included. A quantitative AEF color map was created from multiphasic CT images using prototypic software. The AEF of tumor, tumor-adjacent parenchyma, and tumor-free parenchyma in the metastasis group; and the AEF of tumor-free parenchyma in the non-metastasis group were measured. In addition, in 28 patients with colorectal cancer for whom follow-up CT scans were available, the AEF on baseline CT scans was compared according to the initial response to chemotherapy in the response (n = 11) vs. the non-response group (n = 17).

Result

In the metastasis group, the AEF of metastases (58.9 ± 15.8) was significantly higher than that of tumor-adjacent parenchyma (35.5 ± 15.4) (P < 0.0001). In addition, tumor-adjacent parenchyma had a higher AEF than tumor-free parenchyma (26.4 ± 7.5) (P < 0.0001). The AEF of tumor-free parenchyma in the metastasis group and that in the non-metastasis group (25.4 ± 3.7) did not show a significant difference. Of the patients with colorectal liver metastases, the response group demonstrated a significantly higher AEF of metastases (65.5 ± 9.6) than the non-response group (51.3 ± 13.2) (P < 0.01).

Conclusion

Adding AEF mapping to multiphasic CT images can improve the demonstration of the hemodynamic features of liver metastases and may be helpful for predicting the tumor response in limited groups of patients with colorectal liver metastases.     

Human in-vivo 31P MR Spectroscopy of Benign and Malignant Breast Tumors

Objective

To assess the potential clinical utility of in-vivo 31P magnetic resonance spectroscopy (MRS) in patients with various malignant and benign breast lesions.

Materials and Methods

Seventeen patients with untreated primary malignant breast lesions (group I), eight patients with untreated benign breast lesions (group II) and seven normal breasts (group III) were included in this study. In-vivo 31P MRS was performed using a 1.5 Tesla MR scanner. Because of the characteristics of the coil, the volume of the tumor had to exceed 12 cc (3×2×2 cm), with a superoinferior diameter at least 3 cm. Mean and standard deviations of each metabolite were calculated and metabolite ratios, such as PME/PCr, PDE/PCr, T-ATP/PCr and PCr/T-ATP were calculated and statistically analyzed.

Results

Significant differences in PME were noted between groups I and III (p=0.0213), and between groups II and III (p=0.0213). The metabolite ratios which showed significant differences were PME/PCr (between groups II and III) (p=0.0201), PDE/PCr (between groups I and III, and between groups II and III) (p=0.0172), T-ATP/PCr (between groups II and III) (p=0.0287), and PCr/T-ATP (between groups II and III) (p=0.0287). There were no significant parameters between groups I and II.

Conclusion

In-vivo 31P MRS is not helpful for establishing a differential diagnosis between benign and malignant breast lesions, at least with relatively large lesions greater than 3 cm in one or more dimensions.     

Do arachnoid cysts grow?

Summary The volumes of intracranial arachnoit cysts were measured in 136 CT scans of 86 patients. Absolute and relative cyst size was calculated. Left hemisphere and middle cranial fossa location prevailed. A slight negative correlation of relative cyst size with age (r=–0.21, NS) disappeared when analysis was restricted to the adult age group (20 years). After the sample was divided into two groups according to relative cyst size (cysts less than mean volume vs cysts greater than mean volume), small AC showed no correlation with age, while large AC correlated positively with age (r=0.79,P<0.05). A subgroup of large AC appears to expand with time, while the majority of small AC remain unchanged.     

Proportional anatomical stereotactic atlas for visual interpretation of brain SPET perfusion images

A semi-automatic method was developed to determine the anterior (AC) and posterior (PC) commissures on brain single-photon emission tomographic (SPET) perfusion images, and then to draw the proportional anatomical Talairach's grid on each axial SPET image. First, the AC-PC line was defined on SPET images from the linear regression of four internal landmarks (frontal pole of the brain, inferior limit of the anterior corpus callosum, sub-thalamic point and occipital pole). Second, the SPET position of AC and PC points on the AC-PC line was automatically determined from measurements made on hard copies of magnetic resonance (MR) images of the patients. Finally, a proportional Talairach's grid was automatically drawn on each axial SPET image. To assess the accuracy of localization of AC and PC points, co-registered technetium-99m hexamethylpropylene amine oxime SPET and MR images from 11 subjects were used. The mean displacements between estimated points on SPET and true points on MRI (x=sagittal, y=frontal and z=axial displacement) were calculated. The mean displacements (in mm) were x=–1.4±1.8, y=–1.7±3.3 and z=–1.1±2.5 for AC, and x=–1.8±1.8, y=0.3±3.2 and =–1.3±2.7 for PC. These displacements represented an error of less than 5 mm at the anterior or posterior pole of the brain or at the vertex. Intra- and inter-observer comparisons did not reveal significant differences in mean displacements. Thus, this semi-automatic method results in reproducible and accurate stereotactic localization of SPET perfusion abnormalities. This method can be used routinely for repeat follow-up studies in the same subject as well as in different individuals without requiring SPET MRI co-registration.     

Saturation effects in phosphorus-31 magnetic resonance spectra of the human liver

Phosphorus-31 liver spectra were recorded from 6 controls and 12 patients with liver disease using TR values of 0.5 and 5 s and a pulse angle of 45 degrees. One of the control subjects was also examined at seven TR values ranging from 0.5 to 20 s. Spectra from one additional patient were collected at TRs of 0.5, 1, and 2 s only. There was a significant increase in the mean ratio of peak areas phosphomonoesters (PME)/beta-ATP in 9 of the 13 patients and a decrease in phosphodiesters (PDE)/beta-ATP in 3 of the patients, compared with controls, at the longer TR values. The saturation factors for PME and PDE were greater than those for Pi and beta-ATP, and spectral abnormalities in disease were often more evident as the TR value was increased from 0.5 to 5 s. Acquisition parameters need to be chosen with a knowledge of the impact that saturation effects have on metabolite quantification and spectral contrast.     

31P MR spectroscopic imaging detects regenerative changes in human liver stimulated by portal vein embolization

Purpose:

First, to evaluate hepatocyte phospholipid metabolism and energetics during liver regeneration stimulated by portal vein embolization (PVE) using proton‐decoupled ³¹P MR spectroscopic imaging (³¹P‐MRSI). Second, to compare the biophysiologic differences between hepatic regeneration stimulated by PVE and by partial hepatectomy (PH).

Materials and Methods:

Subjects included six patients with hepatic metastases from colorectal cancer who were scheduled to undergo right PVE before definitive resection of right‐sided tumor.³¹P‐MRSI was performed on the left liver lobe before PVE and 48 h following PVE. Normalized quantities of phosphorus‐containing hepatic metabolites were analyzed from both visits. In addition, MRSI data at 48 h following partial hepatectomy were compared with the data from the PVE patients.

Results:

At 48 h after PVE, the ratio of phosphomonoesters to phosphodiesters in the nonembolized lobe was significantly elevated. No significant changes were found in nucleoside triphosphates (NTP) and Pi values. The phosphomonoester (PME) to phosphodiester (PDE) ratio in regenerating liver 48 h after partial hepatectomy was significantly greater than PME/PDE 48 h after PVE.

Conclusion:

³¹P‐MRSI is a valid technique to noninvasively evaluate cell membrane metabolism following PVE. The different degree of biochemical change between partial hepatectomy and PVE indicates that hepatic growth following these two procedures does not follow the same course. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.     

31P MRS as an early prognostic indicator of patient response to chemotherapy.

In this study 31P spectral changes were closely monitored following the initial administration of cytotoxic drugs and related to five parameters of patient response. Pre- and postchemotherapy 31P MRS examinations were performed on 16 patients with large, malignant tumors. These included four tumor types: (i) lymphoma (n = 7), (ii) breast carcinoma (n = 4), (iii) musculoskeletal tumors (n = 4), and (iv) adenocarcinoma (n = 1). A mean of 5 spectra/patient (range 2-10) was performed following the initial chemotherapy. The spectral trends exhibited by 14 of 16 patients reached "points of maximum change," after which they began to revert toward prechemotherapy values. In 2 of 16 patients that did not respond to the initial chemotherapy regimen, no spectral trends were observed. The degree of change of certain spectral parameters, namely, decreases in PME, PME/PDE, PME/PCr, PME/NTP, PDE/PCr, and tumor pH, as well as increases in the ratios Pi/PME and Pi/PDE, were associated with good patient response and separated responders from nonresponders. Pi/PME appears the most promising for discriminating partial from complete responders.     

MELD Score as a Predictor of Early Death in Patients Undergoing Elective Transjugular Intrahepatic Portosystemic Shunt (TIPS) Procedures

Purpose To Evaluate the MELD score as a predictor of 30-day mortality in patients undergoing elective TIPS procedures.Methods This was a retrospective, IRB-approved study. The medical records of all patients who underwent a TIPS procedure between May 1, 1999 and June 1, 2003 in a single institution were reviewed. Patients who underwent elective TIPS were selected. Elective TIPS was performed in 119 patients with a mean age of 55.1 (± 9.6) years. The MELD and Child-Pugh scores before TIPS, etiology of cirrhosis, portosystemic gradients before and after TIPS, procedure time, and procedural complications were obtained from the medical records. The MELD and Child-Pugh scores before TIPS were compared between the survivor group (SG) and the early death (EDG) group. The early death rate was calculated for MELD score subgroups (1–10, 11–17, 18–24, and >24). Data were analyzed using the Fisher exact test, chi-square test and independent-sample t-test. A p value of less than 0.05 was considered significant.Results Technical success rate was 100%. The early death rate was 10.9% (13/119). The mean MELD scores before TIPS were 19.4 (± 5.9) (EDG) and 14 (± 4.2) (SG) (p=0.025). The early death rate was highest in the pre-TIPS MELD > 24 subgroup. The Child-Pugh scores were 9.0 (± 1.6) (SG) and 9.8±1.06 (EDG) (p=0.08). The mean portosystemic gradients before TIPS were 20.5 (± 7.7) mmHg (EDG) and 22.7 (± 7.3) (SG) (p > 1) and the mean portosystemic gradients after TIPS were 6.5 (± 3.5) (EDG) and 6.9 (± 2.4) (SG) (p > 1). The mean procedural times were 95.6 (± 8.4) min (EDG) and 89.2 (± 7.5) min (SG) (p > 1). No early death was attributed to a fatal complication during TIPS.Conclusion The MELD score is useful in identifying patients at a higher risk of early death after an elective TIPS. On th basis of our results, we do not endorse elective TIPS in patients with MELD scores > 24.     

Assessment of absolute metabolite concentrations in human tissue by 31P MRS in vivo. Part I: Cerebrum,cerebellum, cerebral gray and white matter

Absolute metabolite concentrations were determined in four different brain regions using phosphorus magnetic resonance spectroscopy (³¹P MRS) on 10 healthy adult volunteers. Localized spectra were collected simultaneously from the cerebellum and the cerebrum and, later, from deep white matter and cortical gray matter by means of a two-volume lSlS pulse sequence and a Helmholtz-type RF-coil. Each brain spectrum was quantified with a calibration spectrum from a head-shaped simulation phantom. A time-domain fitting routine was used to process the fully relaxed data. Several metabolite concentrations (mmolAiter) differed significantly between the cerebrum and the cerebellum (PME = 3.2 f 0.3 and 4.0 & 0.6, PC:r = 2.9 & 0.3 and 3.9 f 0.4, NTP = 2.9 f 0.2 and 2.6 & 0.2, respectively) and between cortical gray matter and deep white matter (PME = 3.1 f 0.4 and 4.3 ± 0.8, PDE = 10.1 f 2.5 and 14.2 & 2.6, respectively). The concentration of free magnesium ion was found to be similar in all four brain regions (0.53 ± 0.21 mmol/liter) but the intracellular pH was significantly higher in the cerebellum (7.04 ± 0.03) than in the cerebrum (6.99 ± 0.02).