MR Spectroscopy and Perfusion MR Imaging Findings of Intracranial Foreign Body Granuloma: a Case Report

We report a case of intracranial foreign body granuloma that showed features of a high grade tumor on magnetic resonance (MR) imaging. However, the relative cerebral blood volume was not increased in the enhancing mass on perfusion MRI and the choline/creatine ratio only slightly increased on MR spectroscopy. The results suggest that the lesion is benign in nature. Perfusion MRI and MR spectroscopy may be helpful to differentiate a foreign body granuloma from a neoplastic condition.

Multidisciplinary Functional MR Imaging for Prostate Cancer

Various functional magnetic resonance (MR) imaging techniques are used for evaluating prostate cancer including diffusion-weighted imaging, dynamic contrast-enhanced MR imaging, and MR spectroscopy. These techniques provide unique information that is helpful to differentiate prostate cancer from non-cancerous tissue and have been proven to improve the diagnostic performance of MRI not only for cancer detection, but also for staging, post-treatment monitoring, and guiding prostate biopsies. However, each functional MR imaging technique also has inherent challenges. Therefore, in order to make accurate diagnoses, it is important to comprehensively understand their advantages and limitations, histologic background related with image findings, and their clinical relevance for evaluating prostate cancer. This article will review the basic principles and clinical significance of functional MR imaging for evaluating prostate cancer.

A Meta-Analysis of the Accuracy of Prostate Cancer Studies Which Use Magnetic Resonance Spectroscopy as a Diagnostic Tool

OBJECTIVE: We aimed to do a meta-analysis of the existing literature to assess the accuracy of prostate cancer studies which use magnetic resonance spectroscopy (MRS) as a diagnostic tool. MATERIALS AND METHODS: Prospectively, independent, blind studies were selected from the Cochrane library, Pubmed, and other network databases. The criteria for inclusion and exclusion in this study referenced the criteria of diagnostic research published by the Cochrane center. The statistical analysis was adopted by using Meta-Test version 6.0. Using the homogeneity test, a statistical effect model was chosen to calculate different pooled weighted values of sensitivity, specificity, and the corresponding 95% confidence intervals (95% CI). The summary receiver operating characteristic (SROC) curves method was used to assess the results. RESULTS: We chose two cut-off values (0.75 and 0.86) as the diagnostic criteria for discriminating between benign and malignant. In the first diagnostic criterion, the pooled weighted sensitivity, specificity, and corresponding 95% CI (expressed as area under curve [AUC]) were 0.82 (0.73, 0.89), 0.68 (0.58, 0.76), and 83.4% (74.97, 91.83). In the second criterion, the pooled weighted sensitivity, specificity, and corresponding 95% CI were 0.64 (0.55, 0.72), 0.86 (0.79, 0.91) and 82.7% (68.73, 96.68). CONCLUSION: As a new method in the diagnostic of prostate cancer, MRS has a better applied value compared to other common modalities. Ultimately, large scale RCT (randomized controlled trial) randomized controlled trial studies are necessary to assess its clinical value.

The Differences of the Magnetic Resonance Spectroscopy Findings Between a Subacute Infarction and a Malignant Glioma with a Similar Mass-Like Enhancing Lesion

PURPOSE: We evaluated the usefulness of magnetic resonance spectroscopy (MRS) method to differentiate the mass-like enhancing subacute infarction from malignant gliomas. MATERIALS AND METHODS: Twenty patients (M:F =11:9, mean age: 56.1 yrs) with mass-like enhancing lesions (via an MRI) were studied. Ten of the twenty patients suffered a subacute infarction, whereas the other ten had malignant gliomas. The subacute infarctions were confirmed clinically by a follow-up MRI, while malignant gliomas were confirmed via surgical biopsies. We checked the metabolite peak intensity (Choline [Cho], Creatine [Cr], N-acetyl-aspartate [NAA]) and the metabolite ratios (Cho/Cr, NAA/Cr) of (1)H MRS data, obtained on mass-like enhancing lesion in subacute infarction and malignant glioma. RESULTS: Of the (1)H MRS confirmed, the subacute infarctions (10 cases), three metabolites were identified at peak intensity (NAA, Cho and Cr peak intensity), which decreased below the normal value, while eight of ten patients (80%) of the malignant gliomas, showed a noticeable increase in Cho peak intensity, with decreased NAA and Cr peak intensity. The Cho peak intensity was statistically different between the two groups (p < 0.05). The two groups revealed that all increased Cho/Cr ratio; however, the malignant glioma group showed an increase in Cho/Cr ratio over the subacute infarction group (p < 0.05). CONCLUSION: The MRS findings revealed that the decreased Cho level, as well as the slightly increased Cho/Cr ratio on the mass-like enhancing lesion, suggests a subacute infarction rather than a malignant glioma.

The Usefulness of In Vitro Proton Magnetic Resonance Spectroscopy for Differentiating Between Abdominal Body Fluids

PURPOSE: The purpose of this study was to determine whether in vitro proton (1H) magnetic resonance spectroscopy (MRS) is useful for distinguishing between abdominal types of fluids. MATERIALS AND METHODS: Thirty fluid samples that were obtained from patients who were undergoing diagnostic or therapeutic percutaneous drainage of abdominal fluids were examined in this study. According to their gross appearance and smell, each sample was classified as either purulent fluid (n=12) or non-purulent fluid (n=18). The non-purulent fluids were subdivided into hemorrhagic fluid (n=2), serosanguinous fluid with debris (n=2), and serosanguinous fluid without debris (n=14). In addition, according to the cytologic analysis, each sample was classified as either benign fluid (n=23) or malignant fluid (n=7). A set of humoral pathological examinations that included biochemical analysis and culture of the fluid were performed for all the fluid samples. In vitro 1H MRS was performed by using a 1.5T MR system and a birdcage head coil. MR spectra were obtained by using point-resolved spectroscopy (PRESS) (TR/TE=2000/30 msec) with water suppression. The MR spectra were analyzed on the basis of agreement between a radiologist and a physicist who worked in consensus. RESULTS: The MR spectra obtained from 30 samples could be classified into 8 different patterns, according to the presence of lipid (0.9/1.3 ppm), lactate (1.3 ppm), acetate (1.9 ppm), and succinate (2.4 ppm) peaks. The MR spectral patterns of the purulent fluids (n=12) were classified as follows: pattern-1 (n=7, 58%), pattern-2 (n=2, 17%), pattern-3 (n=1, 8%), pattern-6 (n=1, 8%) and pattern-8 (n=1, 8%). The MR spectral patterns of the non-purulent fluids (n=18) were classified as follows: pattern-4 (n=1, 6%), pattern-5 (n=5, 28%), pattern-6 (n=1, 6%), pattern-7 (n=3, 17%) and pattern-8 (n=8, 44%). The MR spectral patterns of the purulent fluids were significantly different from those of the non-purulent fluids (p < .05). The MR spectral patterns of benign fluids (n=23) were classified as follows: pattern-1 (n=7, 30%), pattern-2 (n=2, 9%), pattern-3 (n=1, 4%), pattern-4 (n=1, 4%), pattern-5 (n=3, 13%), pattern-6 (n=2, 9%), pattern-7 (n=1, 4%) and pattern-8 (n=6, 26%). The MR spectral patterns of malignant fluids (n=7) were classified as follows: pattern-5 (n=2, 29%), pattern-7 (n=2, 29%) and pattern-8 (n=3, 43%). No significant difference was found between the spectral patterns of the benign and malignant fluids (p= .300). CONCLUSION: In vitro 1H MRS could be useful for differentiating between purulent fluid and non-purulent fluid.

MR Imaging and Spectroscopic Findings of Primary Angiosarcoma of the Breast: A Case Report

Angiosarcoma is a rare, malignant tumor of the breast. MR spectroscopy and a new breast MR imaging technique called MR angiography were used to study a case of multifocal primary angiosarcoma of the breast. The mass was isointense on the T1-weighted images and it was hyperintense on the T2-weighted images. Early fast enhancement and draining vessels with a washout curve were revealed by the dynamic enhancement. The MR spectroscopy did not show a choline peak.

Localized 1H-MR Spectroscopy in Moyamoya Disease before and after Revascularization Surgery

OBJECTIVE: To evaluate, using localized proton magnetic resonance spectroscopy (1H-MRS), the cerebral metabolic change apparent after revascularization surgery in patients with moyamoya disease. MATERIALS AND METHODS: Sixteen children with moyamoya disease and eight age-matched normal controls underwent MR imaging, MR angiography, conventional angiography, and 99mTc- ECD SPECT. Frontal white matter and the basal ganglia of both hemispheres were subjected to localized 1H-MRS, and after revascularization surgery, four patients underwent follow-up 1H-MRS. RESULTS: Decreased NAA/Cr ratios (1.35+/-0.14 in patients vs. 1.55+/-0.24 in controls) and Cho/Cr ratios (0.96+/-0.13 in patients vs. 1.10+/-0.11 in controls) were observed in frontal white matter. After revascularization surgery, NAA/Cr and Cho/Cr ratios in this region increased. In the basal ganglia, there is no abnormal metabolic ratios. CONCLUSION: Localized 1H-MRS revealed abnormal metabolic change in both hemispheres of children with moyamoya disease. Because of its non-invasive nature, 1H-MRS is potentially useful for the preoperative evaluation of metabolic abnormalities and their postoperative monitoring.

Fire-Related Post-Traumatic Stress Disorder: Brain 1H-MR Spetroscopic Findings

OBJECTIVE: To investigate the MR imaging and 1H-MR spectroscopic findings of acute fire-related post-traumatic stress disorder (PTSD). MATERIALS AND METHODS: Sixteen patients (M: F=10: 6; mean age, 16 years) with fire-related PTSD underwent MR imaging and 1H-MR spectroscopy, and for control purposes, the procedures were repeated in eight age-matched normal volunteers. In all patients and controls, the regions of interest where data were acquired at MRS were the basal ganglia (BG), frontal periventricular white matter (FWM), and parietal periventricular white matter (PWM). RESULTS: In all patients with PTSD, MR images appeared normal. In contrast, MRS showed that in the BG, NAA/Cr ratios were significantly lower in patients than in volunteers. This decrease did not, however, show close correlation with the severity of the neuropsychiatric symptoms. In patients, neither NAA/Cr ratios in FWM nor PWM, nor Cho/Cr ratios in all three regions, were significantly different from those in the control group. CONCLUSION: Decreased NAA/Cr ratios in the BG, as seen at 1H-MRS, might be an early sign of acute fire-related PTSD.

Acute Necrotizing Encephalopathy: Diffusion MR Imaging and Localized Proton MR Spectroscopic Findings in Two Infants

In this report, we describe the findings of diffusion MR imaging and proton MR spectroscopy in two infants with acute necrotizing encephalopathy in which there was characteristic symmetrical involvement of the thalami. Diffusion MR images of the lesions showed that the observed apparent diffusion coefficient (ADC) decrease was more prominent in the first patient, who had more severe brain damage and a poorer clinical outcome, than in the second. Proton MR spectroscopy detected an increase in the glutamate/glutamine complex and mobile lipids in the first case but only a small increase of lactate in the second. Diffusion MR imaging and proton MR spectroscopy may provide useful information not only for diagnosis but also for estimating the severity and clinical outcome of acute necrotizing encephalopathy.

In vivo 1H MR Spectroscopic Features of Hepatic and Renal Cysts

PURPOSE: To evaluate the feasibility of in-vivo 1H magnetic resonance spectroscopy (1H-MRS) for differentiation between hepatic and renal cysts, with emphasis on the analysis of cystic content. MATERIALS AND METHODS: The 1H-MR spectra of 43 cystic lesions (15 hepatic and 28 renal) obtained using in -vivo 1H-MRS at 1.5 T and with a localized proton STEAM sequence were evaluated. We calculated the ratio of the peak area of lipid/water (Rlipid/water), protein/water (Rprotein/water) and lipid/protein (Rlipid/protein), paying particular attention to identifying differences in peak area ratios between the two types of cyst. RESULTS: The 1H-MR spectra from 26.7% (4/15) of hepatic and 67.9% (19/28) of renal cysts showed the lipid peak as most prominent. Mean+/-standard deviations of the Rlipid/water of hepatic and renal cysts were 0.38+/-0.30x10-6 and 8.42+/-23.24x10-6, respectively; for Rprotein/water the corresponding figures were 0.83+/-0.74x10-6 and 1.50+/-2.94x10-6, and for Rlipid/protein, 0.57+/-0.64 and 2.44+/-3.26. All differences were statistically significant (p<0.05), and positive correlation between lipid and protein in hepatic and renal cysts was demonstrated. CONCLUSION: The different in-vivo 1H-MRS findings, for hepatic and renal cysts can be used in comparative study of cystic tumors of the liver and kidney.

Influence of Mn-DPDP on MRI and Proton MR Spectroscopy of the Liver

PURPOSE: To determine the influence of manganese dipyridoxyl diphosphate (Mn-DPDP) on MRI and proton MRS. MATERIALS AND METHODS: In an in-vitro study designed to determine changes in the lipid peak at 1.3 ppm, 4.7T MR equipment was used to obtain proton MR spectrographic images of a lipid solution of varying concentration, with and without Mn-DPDP. Before; at 10, 20, and 30 minutes; and at 1, 2, 4, and 24 hours after the IV injection of Mn-DPDP (10umol, 1ml/kg), the concentration of Mn in liver tissue was measured by atomic absorption spectrometry. At the same intervals, T1-weighted MR images were obtained, the signal intensity ofthe liver was thus determined, and the relative enhancement ratio was calculated. MRS of rabbit liver was performed serially at the same intervals, and the peak areas of metabolites, as well as their peak areas relative to lipids, were calculated. The findings were correlated with tissue Mn concentration. RESULTS: At 1.3 ppm with Mn-DPDP, MRS showed that the peak area of the lipid had decreased. Tissue Mn concentration increased just after Mn-DPDP injection and peaked after 20 minutes, decreasing to a level within the normal range after 24 hours. Serial changes in the signal intensity of the liver, as seen at MRI, showed a similar pattern to that of Mn concentration. There was reverse correlation between serial change in the peak area of lipids at 1.3 ppm and Mn concentration after Mn-DPDP injection. CONCLUSION: At T1-weighted MR imaging, the injection of Mn-DPDP led to the enhancement of liver tissue, and at MRS, the lipid peak at 1.3 ppm decreased. There was close correlation between these effects and tissue Mn concentration.

In-vivo Proton Magnetic Resonance Spectroscopy in Adnexal Lesions

OBJECTIVE: To explore the in-vivo 1H- MR spectral features of adnexal lesions and to characterize the spectral patterns of various pathologic entities. MATERIALS AND METHODS: Thirty-one patients with surgically and histopathologically confirmed adnexal lesions underwent short echo-time STEAM (stimulated echo acquisition method) 1H- MR spectroscopy, and the results obtained were analysed. RESULTS: The methylene present in fatty acid chains gave rise to a lipid peak of 1.3 ppm in the 1H- MR spectra of most malignant tumors and benign teratomas. This same peak was not observed, however, in the spectra of benign ovarian epithelial tumors: in a number of these, a peak of 5.2 ppm, due to the presence of the olefine group (-CH=CH-) was noted. The ratios of lipid peak at 1.3 ppm to water peak (lipid/water ratios) varied between disease groups, and in some benign teratomas was characteristically high. CONCLUSION: An intense lipid peak at 1.3 ppm is observed in malignant ovarian tumors but not in benign epithelial tumors. 1H- MRS may therefore be helpful in the differential diagnosis of adnexal lesions.

Quantification of Dextrose in Model Solution by H MR Spectroscopy at 1.5T

PURPOSE: To evaluate the feasibility of proton magnetic resonance spectroscopy (1H-MRS) using a 1.5T magnetic resonance (MR) imager for quantification of the contents of model solutions. MATERIALS AND METHODS: We prepared model solutions of dextrose+water and dextrose+water+ethanol at dextrose concentrations of 0.01% to 50% and 0.01% to 20%, respectively. Using these solutions and a 1.5T MR imager together with a high-resolution nuclear magnetic resonance (NMR) spectroscope, we calculated the ratios of dextrose to water peak, (dextrose+ethanol) to water peak, and (dextrose+ethanol) to ethanol peak, as seen on MR and NMR spectra, analysing the relationships between dextrose concentration and the ratios of peaks, and between the ratios of the peaks seen on MR spectra and those seen on NMR spectra. RESULTS: Changes in the ratios between dextrose concentration and dextrose to water peak, (dextrose+ethanol) to water peak and (dextrose+ethanol) to ethanol peak, as seen on MR spectra, were statistically significant, and there was good linear regression. There was also close correlation between the ratios of the observed on MR and NMR spectra. The results depict the quantification of dextrose concentration according to the ratios of spectral peaks obtained by proton MRS at 1.5T. CONCLUSION: Using proton MRS at 1.5T, and on the basis of the ratios of spectcal peaks, it was possible to quantify the concentration of dextrose in model solutions of dextrose+water and dextrose+water+ethanol. The results of this study suggest that for quantifying the contents of biofluids, the use of low-tesla 1H-MRS is feasible.

Measurement of Lipid Content in Gallbladder Bile Using in- and opposed-phase MR Images and in vivo Proton MR Spectroscopy

PURPOSE: To evaluate the utility of signal intensity differences between in- and opposed-phase MRI and the lipid peak ratio in in-vivo proton MR spectroscopy of the gallbladder as diagnostic tools for measuring the lipid content of gallbladder bile. MATERIALS AND METHODS: Twenty-six normal volunteers underwent MR imaging (FMPSPGR) and in-vivo proton MR spectroscopy of the gallbladder. In all cases the results of liver function tests were normal, as were cholesterol levels, and ultrasonography of the gaubladder revealed nothing unusual. For MRI and MRS a 1.5T unit (Signa Horizon; GE Medical Systems, Milwaukee, U.S.A.) was used. In-phase and opposed-phase coronal-section MR images(FMPSPGR; TR=125 msec, TE=1.8, 4.2 msec) of the gallbladder were obtained, and differences in signal intensity thus determined. For proton MR spectroscopy of the gallbladder, a localized proton STEAM sequence was employed. A single voxel of 1-8 cm3 was placed at the center of the gallbladder cavity, peak areas at 0.8-1.6 ppm (lipid), 2.0-2.4 ppm, 3.2-3.4 ppm, 3.9-4.1 ppm, and 5.2-5.4 ppm were measured by proton MRS and the relative peak area ratios of peak 0.8-1.6 ppm/other peaks were calculated. The degree of correlation between signal intensity differences at MRI and the relative peak area ratio of lipid in proton MRS was estimated using the p-value and Pearson's correlation coefficient. RESULTS: Signal intensity differences ranged from 11.3 to 43.4% (mean, 26+/-8.9%), and the range of lipid peak area ratio at MRS was 0.10-0.97 (mean, 0.66+/-0.21). There was significant correlation between the two measured values (p=0.014, Pearson's correlation coefficient=0.478). CONCLUSION: In normal cystic bile, signal intensity differences at in- and opposed-phase MRI and relative lipid peak area ratios at MRS varied, though both methods could be used diagnostically for measuring the lipid contents of body tissue.

In vivo Proton MR Spectroscopic Findings of Focal Hepatic Lesions: Initial Experience

PURPOSE: To investigate the in vivo proton MRS features of various focal hepatic lesions and to distinguish these features according to the involved. MATERIALS AND METHODS: Twenty-five hepatic lesions [hepatocellular carcinoma (n=7), cholangiocarcinoma(n=3), metastatic tumor (n=9), hemangioma (n=3), hepatic abscess (n=2), lymphoma (n=1)] underwent proton MR spectroscopy using a 1.5T unit and a localized proton STEAM sequence, without respiratory interruption, The findings of this in-vivo sequence were then reviewed, with particular attention to the presence and location of dominant peaks. RESULTS: In-vivo proton MR spectra were successfully acquired in all cases. A dominant lipid peak appeared in the MR spectra of the hepatocellular carcinomas, metastatic tumors, hepatic abscesses, lymphoma, one hemangioma and one cholangiocarcinoma(88%) at 1.3ppm, but not in two cholangiocarcinomas and one hemangioma. The spectral peaks of other metabolites appeared very irregular and even different in the same disease. CONCLUSION: In focal hepatic lesions, the spectra obtained during in-vivo proton MRS were useful, and a lipid peak was most frequent and dominant. Among the various neoplasms there were, however, no specific MR spectral features, and nor did such features vary according to the specific pathologic entity.

Human Breast Cancer: In Vivo And In Vitro H MR Spectroscopy

PURPOSE: The purpose of this study was to determine, using in vivo and in vitro 1H MRS (MR spectroscopy), the characteristic biochemical metabolites related with breast cancer, and to assess the clinical usefulness and limitations of this modality. MATERIALS AND METHODS: For in vivo 1H MRS, nine patients with breast cancer and two normal volunteers were examined on a 1.5 T MR imager equipped with facilities for spectroscopy. In order to localize the breast lesion, axial and sagittal T1-weighted images and fat-suppressed T2-weighted images were obtained just prior to MRS; MR spectra were acquired at TR=3000 msec and TE=144 msec. For in vitro 1H MRS, breast tumor and adja-cent normal tissue were extracted from 13 patients with breast cancer, and in two of these, both in vivo and in vitro 1H MRS were performed. All in vitro 1H MRS specimens were immediately immersed in liquid nitrogen, and then in a preparation of perchloric acid. For quantitative analysis of the MR spectra of cancerous and normal breast tissue, the paired t-test was used (p < 0.05). RESULTS: At1H MRS in vivo, choline and two lipids were identified at 3.21 ppm, and 1.33 ppm and 0.9 ppm, re-spectively. The distinction between cancerous and normal breast tissue was based on the higher level of choline (3.21 ppm) present in the former. At 1H MRS in vitro, on the other hand, mean and standard deviation (% standard deviation) for the various metabolites in cancerous and normal breast tissue were as follows: choline, 30.195 +/- 2.448(8.108) and 22.648 +/- 1.938(8.556); trimethylamine, 3.425 +/- 0.335(9.769) and 0.640 +/- 0.066(10.325); sarcosine, 3.425 +/- 0.335(9.769) and 0.640 +/- 0.099(15.394); lactate, 16.388 +/- 1.134(6.922) and 9.715 +/- 0.385(3.965); inositol, 1.970 +/- 0.282(14.334) and 3.859 +/- 0.502(13.020); and taurine, 6.614 +/- 0.556(8.412) and 10.748 +/- 1.206(11.222). High levels of choline (p=0.026), trimethylamine (p=0.001), sarco-sine (p=0.009), and lactate (p=0.009), and lower levels of inositol (p=0.006) and taurine (p=0.008) were char-acteristic findings in cancerous as compared with normal breast tissue, with significantly different results. CONCLUSION: 1H MRS both in vitro and in vivo showed that increased choline levels were present in cancerous breast tissue, but that normal tissue does not contain choline. The presence of choline could therefore be used as a marker for malignancy in breast lesions. Information provided by in vitro 1H MRS, together with the development of in vivo 1H MRS with high field strength and high resolution, may be very useful for the diagnosis of breast cancer.

Proton MR Spectroscopic Features According to Change of Hepatic Parenchymal Iron Content after SPIO Injection

PURPOSE: To determine the effect of iron on proton MR spectra (1H-MRS) by evaluating changes in 1H-MRS of the liver according to changes in hepatic parenchymal iron content. MATERIALS AND METHODS: We evaluated serial changes in 1H-MRS of the liver after intravenous infusion of SPIO in 40 rabbits. These were divided into eight groups of five, and in each group, respectively, 1H-MRS and T2WI MR images were acquired prior to SPIO infusion, just after infusion, and at 15 minutes and 1, 2, 4, 24 and 96 hours after infusion. MR spectra were evaluated with particular attention to the curve pattern observed at specific times after the infusion of SPIO, and the results were correlated with the signal intensity observed on T2W1 images and the histologic giade of ilon content of samples of resected liver parenchyma. RESULTS: As observed on T2WI, the mean signal intensity of rabbit liver in its pre-SPIO infusion state, just after infusion, at 15 minutes, and at 1, 2, 4, 24 and 96 hours after SPIO infusion was 121.3 +/-15.5, 41.5 +/-12.7, 30.3 +/-7.9, 31.3 +/-3.5, 33.6 +/-9.4, 45.5 +/-10.9, 80.3 +/-15.7 and 110.4 +/-22.9, respectively(p<0.05). Mean standard deviation of the ratio of the area of the peak (3.9-4.1 ppm) / lipid peak (1.3 ppm) peak at each of the above times except for the pre-infusion state was 1.10 +/-0.13, 1.86 +/-0.21, 1.80 +/-0.30, 1.76 +/-0.27, 1.74 +/-0.20, 0.07 +/-0.02 and 0.03 +/-0.01, respectively(p<0.05). The hepatic parenchymal iron content increased rapidly from just after SPIO infusion, reaching its maximal level (as revealed by histologic specimens) at 15 minutes, sustaining this for up to 4 hours, and then decreasing gradually over periods of 24 and 96 hours. These results show that serial changes in patterns of MR spectra and the signal intensity seen on T2WI images correlate closely with changes in hepatic parenchymal iron content. CONCLUSION: Elevated hepatic parenchymal iron content leads to increases in the relative intensity of unknown peaks at around 4.0 ppm and decreases in the relative intensity of lipid peaks.

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 x 2 x 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.

Proton MR Spectroscopic Features of Liver Cirrhosis: Comparing with Normal Liver

PURPOSE: The purpose of this study was to determine the proton MR spectroscopic features of liver cirrhosis and the different proton MR spectroscopic features between liver cirrhosis and the normal human liver by comparing the two different conditions. MATERIALS AND METHODS: The investigation involved 30 cases of in-vivo proton MR spectra obtained from 15 patients with liver cirrhosis demonstrated on the basis of radiologic and clinical findings, and from 15 normal volunteers without a past or current history of liver disease. MR spectroscopy involved the use of a 1.5T GE Signa Horizon system (GE Medical Systems, Milwaukee, U.S.A.) with body coil. STEAM (STimulated Echo-Aquisition Mode) with 3000/30 msec of TR/TE was used for signal acquisition; patients were in the prone position and respiration was not interrupted. Cases were assigned to either the cirrhosis or normal group, and using the proton MR spectra of cases of in each group, peak changes occurring in lipids (at 1.3ppm), glutamate and glutamine (at 2.4 -2 .5ppm), phosphomonoesters (at 3.0 -3 .1ppm), and glycogen and glucose (at 3.4 -3 .9ppm) were evaluated. Mean and standard deviation of the ratio of glutamate + glutamine/lipids, phospho-monoesters/lipids, glycogen + glucose/lipids were calculated from the area of their peaks. The ratio of various metabolites to lipid content was compared between the normal and cirrhosis group. RESULTS: The main characteristic change in proton MR spectra in cases of liver cirrhosis compared with normal liver was decreased relative intensity of lipid peak. Mean and standard deviation of ratio of glutamate + g-lutamine/ lipids, phosphomonoesters/lipids, glycogen + glucose/lipids calculated from the area of their peaks of normal and cirrhotic liver were 0.0204 +/-0.0067 and 0.0693 +/-0.0371 (p<0.05), 0.0146 +/-0.0090 and 0.0881 +/-0.0276 (p<0.05), 0.0403 +/-0.0267 and 0.2325 +/-0.1071 (p<0.05), respectively. The other character-istic feature of proton MR spectra of liver cirrhosis was the peak detected at 3.9 - 4.1 ppm with unknown nature. Mean and standard deviation of area ratio of the unknown peak to lipid peak in proton MR spectra of liver cirrhosis was 0.1504 +/-0 . 0 3 5 5 . CONCLUSION: Proton MR spectra of liver cirrhosis revealed decreased intensity of lipid with statistical signifi-cance compared with that of normal liver, and peak at 3.9 -4.1 ppm with unknown nature. In conclusion, liver cirrhosis can be diagnosed non-invasively by the analysis of observed proton MR spectroscopic features.

Hippocampal and Neocortical Metabolite Ratio in Patients with Complex Partial Seizure: Short TE and Long TE Techniques Using Single Voxel Proton MR Spectroscopy

PURPOSE: To compare hippocampal and neocortical metabolite ratios using single-voxel proton MR spectroscopy with different echo times in patients with complex partial seizure. MATERIALS AND METHODS: Using a GE Signa 1.5 T scanner with STEAM and PRESS sequences, automated single voxel proton MRS was used to determine metabolite ratio differences in the hippocampus and neocortex of nine complex partial seizure patients [mesial temporal sclerosis (n=5), status epilepticus (n=1), tumor (n=1), cortical dysplasia (n=1), occipital lobe epilepsy (n=1)]. A total of 20 examinations were performed in the region of the hippocampus (n=17), temporal neocortex (n=1), and parieto-occipital gray matter (n=1). Voxel size range was 5.2 -17.4 cm 3. The calculated creatine (Cr) peak was employed as an internal reference and the relative ratio of N-acetylaspartate (NAA) and choline (Cho) was calculated for both short and long echo times using an automated PROBE/SV (GE Medical Systems) package. Each NAA/Cho ratio obtained using both PRESS and STEAM techniques was compared by means of statistical analysis (paired Student t-test). RESULTS: Using PRESS (long TE, 272 ms), NAA/Cho ratios were successfully calculated in 16 of 20 examinations; in four this was not possible due to noise levels of the Cr and Cho peaks. Using STEAM (short TE, 30 ms) NAA/Cho ratios were successfully calculated in 19 of 20 examinations; in one, the Cho peak could not be measured. Using PRESS and STEAM, mean and standard deviations for the NAA/Cho ratio were 1.22 +/-0.50 and 1.16 +/-0.36, respectively. There were no statistically significant differences in this ratio between the short and long TE method (p <0.01). CONCLUSION: In complex partial seizure patients, no significant metabolite differences were found between short and long echo times of single voxel proton MR spectroscopy. The metabolite ratio at different echo times can be reliably obtained using this simplified and automated PROBE/SV quantitation method.