Proton magnetic resonance spectroscopy (MRS) of metastatic brain tumors: variations of metabolic profile

Background Spectroscopic imaging can be helpful for the noninvasive identification of parenchymal brain tumors. The objective of the present study was the characterization of the metabolic profile of intracranial metastases, based on proton magnetic resonance spectroscopy (MRS). Methods One hundred and four metastatic brain tumors were evaluated by long-echo (TR, 2000 ms; TE, 136 ms) single-voxel volume-selected proton MRS. In 83 patients the tumor fraction within the MRS voxel constituted more than 50%. Results Compared to normal brain, the tumors showed statistically significant decreases of N-acetylaspartate (P < 0.0001), creatine (P < 0.0001), and the [NAA]/choline-containing compounds ratio (P < 0.0001), increases of [Cho] (P < 0.0001) and the mobile lipids/[Cr] ratio (P < 0.0001) and the lactate/[Cr] ratio (P < 0.05), and the more frequent presence of [Lip] (P < 0.0001) and [Lac] (P < 0.0001) resonances. However, the majority of these differences were lost when data for patients whose tumor fraction within the MRS voxel constituted less than 50% were analyzed separately. Determination of the predominant metabolite peak on the MR spectrum [NAA, Cho, Lip] permitted us to define three general metabolic patterns of brain metastases, which, showed statistically significant associations with the size of the neoplasm (P < 0.001), type of its contrast enhancement (P < 0.01), and the extent of perilesional edema (P < 0.05). Conclusion Proton MRS can define metabolically different subsets of metastatic brain tumors, and these characteristics should be taken into consideration during the differential diagnosis of parenchymal brain lesions. The results of this study were presented in part during 64^th Annual Meeting of the Japan Neurosurgical Society, October 5–7, 2005, Yokohama, Japan     

Characterization of brain tumors by MRS,DWI and Ki-67 labeling index

Summary With the advent of fast imaging hardware and specialized software, additional non-invasive magnetic resonance characterization of tumors has become available through proton magnetic resonance spectroscopy (MRS), hemodynamic imaging and diffusion-weighted imaging (DWI). Thus, patterns could be discerned to discriminate different types of tumors and even to infer their possible evolution in time. The purpose of this study was to investigate the correlation between MRS, DWI, histopathology and Ki-67 labeling index in a large number of brain tumors. Localized proton spectra were obtained in 47 patients with brain tumors who subsequently underwent surgery (biopsy or tumor removal). We performed MRS with short echo-time (30ms) and metabolic values in spectra were measured using an external software with 25 peaks. In all patients who had DWI, we measured apparent diffusion coefficients (ADC) in the same region of interest (ROI) where the voxel in MRS was located. In most tumors the histological diagnosis and Ki-67 labeling index had been determined on our original surgical specimen. Cho/Cr, (Lip+Mm)/Cr, NAA/(Cho+Cr) and Glx/Cr indexes in MRS allowed discriminating between low- and high-grade gliomas and metastases (MTs). Likewise, absolute ADC values differentiated low- from high-grade gliomas expressed by Ki-67 labeling index. A novel finding was that high Glx/Cr in vivo MRS index (similar to other known indexes) was a good predictor of tumor grading.     

Multivoxel 3D proton MR spectroscopy in the distinction of recurrent glioma from radiation injury

Objective To explore the usefulness of multivoxel 3D proton MR spectroscopy (¹H-MRS) in assessing the recurrent contrast-enhancing areas at the site of the previously treated gliomas. Materials and methods In 28 patients who had new contrast-enhancing lesions in the vicinity of the previously resected and irradiated high-grade glioma, 3D ¹H-MRS examinations were performed on a 3.0T MR scanner. Spectral data for N-acetylaspartate (NAA), choline (Cho), and creatine (Cr) were analyzed in all patients. Receiver operating characteristic analysis was performed, and the threshold value for tumor differentiation was determined. Diagnosis of these lesions was assigned by means of histopathology and follow-up. Results Diagnostic-quality 3D ¹H-MRS with quantifiable Cho, Cr, and NAA peaks was obtained in 92.9% of the cases. The Cho/NAA and Cho/Cr ratios were significantly higher in recurrent tumor than in radiation injury (P < 0.01), whereas the NAA/Cr ratios were lower in recurrent tumor than in radiation injury (P = 0.02). The Cho/Cr and Cho/NAA ratios were significantly higher in radiation injury than in normal-appearing white matter (P < 0.01), however, the NAA/Cr ratios were lower in radiation injury than in normal-appearing white matter (P = 0.01). Using receiver operating characteristic analysis, the resulting sensitivity, specificity and diagnostic accuracy of 3D ¹H-MRS were 94.1%, 100%, and 96.2%, respectively, based on the cut-off values of 1.71 for Cho/Cr or 1.71 for Cho/NAA or both as tumor criterion. Conclusion 3D ¹H-MRS could differentiate recurrent tumor from radiation injury in patients with recurrent contrast-enhancing lesions in the vicinity of the previously treated gliomas.     

Assessing neurotoxicity from the low-dose radiation component of radiosurgery using magnetic resonance spectroscopy

The aim of the study was to determine if biochemical changes indicative of injury, assessed using magnetic resonance spectroscopic imaging (SI), are observed after stereotactic radiosurgery (SRS). The study included patients who underwent SI immediately before and 1, 30, and 90 days following SRS. Short TE spectra (TR/TE 1000/35 ms) were acquired at the SRS isocenter with a 2D PRESS-CSI sequence on a single 1.5 T scanner. The SRS isodose lines were overlaid on the magnetic resonance imaging slice utilized for SI data acquisition. N-Acetyl aspartate (NAA)/creatine (Cr) and choline (Cho)/Cr ratios were computed for multiple voxels located between the 25 and 50 cGy isodose lines (low dose) and the 200 and 350 cGy isodose lines (medium dose). An analysis of variance and paired t-tests compared metabolite levels at different time points. Twelve patients were enrolled, although 3 were excluded secondary to poor spectral data quality or deviations from the prescribed SI protocol. The median number of voxels analyzed from the low- and medium-dose region was 7 and 4, respectively. No significant changes in metabolite peak height ratios over time were seen in the low-dose region, for either NAA/Cr (P = .89) or Cho/Cr (P = .85). There was no difference in Cho/Cr peak height ratios in the medium-dose region (P = .62). There was an increase in the NAA/Cr peak height ratio in the medium-dose region between day −1 and day +30 (P = .003), followed by a decline to baseline between days +30 and +90 (P = .03). We did not observe a significant decline in NAA/Cr or change in Cho/Cr peak heights in uninvolved brain parenchyma after SRS.     

颅内肿瘤放疗后磁共振质子波谱的变化研究

目的 探讨颅内肿瘤放疗后磁共振质子波谱(1HMRS)的变化.方法 选择需行放疗的颅内肿瘤患者40例,在放疗前后分别观察和测量肿瘤和对侧正常组织的N-乙酰天冬氨酸(NAA)、肌酐(Cr)、乳酸-脂质(Lac-Lip)峰值.计算肿瘤组织放疗前后的NAA/Cr、Cho/Cr、Cho/NAA的比值.结果 颅内肿瘤放射治疗后,1HMRS均表现为Cho明显降低,NAA、Cr下降,Cho/Cr下降最明显,放射性坏死1HMRS表现出Lac-Lip峰.结论 1HMRS可评估颅内肿瘤放疗后的代谢变化,是一种判断疗效有价值的检查方法.     

磁共振质子波谱在颅内肿瘤放疗效果评价中的应用研究

Objective： To evaluate the clinical application of proton magnetic resonance spectroscopy （1HMRS） in patients with radiotherapy treated intracranial tumors. Methods： Forty patients with intracranial tumors underwent multivoxel 1HMRS examination before and after radiotherapy. The concentrations of N-acetyl aspartate （NAA）, choline （Cho） and creatine （Cr） were obtained both in the tumors and the contralateral normal brain regions, The ratios of NANCr, Cho/Cr and Cho/NAA were calculated at the same time and follow-up one year. Results： （1） After radiotherapy, tumors inhibited by radiation had decreased Cho, NAA and Cr on proton MRS. Some cases showed necrotic wave. （2） During the one year follow-up, local tumor recurred in 8 cases and their Cho and Cho/NAA increased high again. Other cases without recurrence, HMRS showed no change. Conclusion： Multivoxel proton MR spectroscopy is available for study of tumor metabolites after radiotherapy and it is a valuable method in the evaluation of radiotherapy treated tumors,     

离体脑肿瘤高分辨魔角旋转磁共振质子波谱

Objective: To explore water soluble metabolite features of brain tumor specimens with HRMAS-1HMRS and its potential clinical value.Methods: There were thirty cases of pathologically proven brain tumor, including 6Ⅰ-Ⅱgrade astrocytomas, 7Ⅲgrade anaplastic astrocytomas, 10 IV grade glioblastomas and 7 meningiomas.Used Varian Company 600 MHz spectrometer with the Nano-probe for acquisition HRMAS-1HMRS, which was postprocessed with jMRUI 3.2 version software.These metabolic probability and their ratios to Cr were summed.Results: (1)HRMAS-1HMRS could resolve NAA, PCr/Cr, GPC Pcho Cho, Ghu/Gin, Gly, Tau, Ala, Lac, ml and so on.All samples showed Lac, 6 samples showed unknown single peak at 3.72 ppm or 3.90 ppm.(2)The mean Cho/Cr of 6Ⅰ-Ⅱgrade astrocytomas was 2.42±1.01(P=0.003, compared with glioblastoma).The mean Cho/Cr of 7 anaplastic astrocytomas was 3.48±0.59 (P=0.01, compared with glioblastoma).The Cho/Cr of 10 glioblastomas broadly ranged from 0.9 to 11.3 (mean 5.40±1.23).FromⅠ-Ⅱgrade astrocytoma to glioblastoma, Ala/Cr, Tau/Cr and Gly/Cr trends were increased; the mean Ala/Cr of glioma was 0.31±0.13.(3)Meningiomas showed higher Ala and Cho.Their Cr was lower than that of gliomas.4/7 cases had no NAA, 3/7 patients had lower NAA.Mean Cho/Cr was 3.56±1.01, Ala/Cr was 0.53±0.28(P=0.006, compared with glioma).Conclusion: HRMAS-1HMRS can show further details in vivo MRS, resolve in vivo spectroscopic metabolite of Cho compound and differentiate the extent of benign and malignant glioma.With the increase in the malignant degree of gliomas, Cho, ml, Ala, Tau and Gly will increase.HRMAS-1HMRS is the only method of isotropic spectroscopy for pathological specimens.     

磁共振波谱在脑胶质瘤放疗中的应用价值

目的 利用多体素磁共振波谱（MRS）探讨脑胶质瘤放疗前后早期代谢的变化。方法 31例诊断明确的脑胶质瘤部分切除术后患者,在放疗前后1周内分别行MRI平扫、增强及MRS检查;在肿瘤强化区、瘤周水肿区设置感兴趣区域（ROI）,采用GE自带软件包Functool分别计算化疗前后代谢物浓度及其比值的变化。结果 放疗后肿瘤强化区域的胆碱（Cho）值较放疗前升高,差异无统计学意义（P＞0.05）;放疗前、后肿瘤强化区域N-乙酰天门冬氨酸（NAA）值分别为39.295±33.778、56.062±39.031,差异有统计学意义（P=0.02）;放疗后瘤周水肿区域Cho值下降、NAA值升高,但差异均无统计学意义（P＞0.05）;放疗后肿瘤强化区及瘤周水肿区Cho／肌酸（Cr）、Cho／NAA、NAA／Cr比值均较放疗前下降,但仅Cho／Cr比值差异有统计学意义（P＜0.05）。结论 MRS可以显示脑胶质瘤的肿瘤强化区及瘤周水肿区放疗后的早期代谢变化,能够较早反映肿瘤放疗的效果。     

1HMRS对脑转移瘤的诊断价值

目的：探讨氢质子磁共振波谱（proton magnetic resonance spectroscopy,1 H MRS）对脑转移瘤的诊断价值。方法：收集术后病理或临床证实脑转移瘤32例。所有患者MRS前均行MR平扫及增强扫描。3．0T MR多体素波谱（TE 144ms）扫描,分别于肿瘤实质、瘤周水肿及正常脑实质取感兴趣区（VOI）,测量代谢物浓度,计算Cho／Cr、NAA／Cr、Cho／NAA值,比较肿瘤实质与正常脑实质、瘤周水肿与正常脑实质代谢物比值的差异,采用配对t检验。观察肿瘤实质是否出现1．3ppm脂峰（Lip）及可流动脂质。结果：肿瘤实质与正常脑实质代谢物比较,Cho／Cr增高、NAA／Cr降低、Cho／NAA增高,差异有统计学意义（P均＜0．05）。瘤周水肿与正常脑实质代谢物比较,Cho／Cr略有增高,NAA／Cr 略有降低,差异无统计学意义（P均＞0．05）;Cho／NAA 增高,差异有统计学意义（P＜0．05）。32例中24例出现Lip,出现率75％,15例出现可流动脂质,出现率46．9％。结论：脑转移瘤的MRS具有一定特征,脂峰及可流动脂质的出现有助于脑转移瘤的诊断。     

Influence of temperature on cerebellar metabolite levels

Objective: The cerebellum is extremely sensitive to heat-induced injury because of the abundance of Purkinje cells. This study explored the influence of temperature on cerebellar metabolite levels by magnetic resonance spectroscopy (MRS).

Materials and Methods: Ten healthy volunteers were recruited to undergo a MRS examination in the summer and winter. Twenty-four ordinary patients with fever underwent the same examination during fever and after recovery. All MR spectras were recorded from the cerebellum. Metabolites ratios including N-acetyl aspartate/creatine (NAA/Cr), choline/creatine (Cho/Cr), and N-acetyl aspartate/choline (NAA/Cho) were calculated.

Results: There are no significant differences in cerebellar metabolite levels in the 10 healthy volunteers during summer and winter (p?>?.05). For the 24 patients with fever, the cerebellar Cho/Cr ratios during fever were increased compared with those after recovery (p?=?.043).

Conclusions: In summary, MRS plays a role in the evaluation of the influence of temperature on cerebellar metabolite levels. It was observed that cerebellar metabolite levels are not influenced by seasonal temperature but are influenced by body temperature.     

Efficacy of Proton Magnetic Resonance Spectroscopy Inclinical Decision Making for Patients with Suspected Malignant Brain Tumors

We wished to determine the utility of single voxel proton (¹H) magnetic resonance spectroscopy (MRS) when used as an alternative or adjunct to brain biopsy in patients harboring lesions suggestive of brain tumors identified by MRI scan. Fifteen patients (age 7–58 years) with MRI scans and clinical histories suggestive of primary brain tumors underwent single voxel ¹H-MRS. MRS (16 regions of interest in 15 patients) was used to aid in differentiation between tumor and other pathologies such as stroke or demyelinating plaque (n=6), radiation necrosis (n=5), or edema (n=5). Spectra were quantified to determine absolute molar values of N-acetyl aspartate (NAA), choline (Cho), creatine (Cr), lactate (LAC), and myo-inositol (mI), metabolite ratios relative to Cr were calculated, and spectra were interpreted based on metabolite ratios. Subsequent clinical management was based on MRS interpretation, and patients were then followed to determine if MRS interpretation accurately predicted clinical outcome or surgical findings. Mean follow-up was 12.5 months (range 3–28 months). MRS suggested the presence of recurrent tumor in 7 cases, all of which were subsequently confirmed by tumor resection (n=4) or disease progression (n=3). MRS suggested the presence of new tumor in 1 case, subsequently confirmed by surgical resection. MRS suggested the presence of necrosis in 3 patients; all 3 remained radiographically stable during the follow-up period, and one was confirmed by stereotactic biopsy. MRS suggested non-neoplastic lesions in 4 cases, 3 of whom were followed until radiographic resolution of lesions and one of which was confirmed as a pyogenic abscess via stereotactic aspiration. Overall, MRS accurately predicted the pathological nature and clinical outcome of lesions in 15/16 (96%) situations, influenced clinical decision making in 12 cases, and altered surgery planning in 7 patients. In appropriate circumstances MRS can reduce the need for biopsy and provide an important guide for clinical decision-making in difficult cases.     

Long-term cerebral metabolite changes on proton magnetic resonance spectroscopy in patients cured of acute lymphoblastic leukemia with previous intrathecal methotrexate and cranial irradiation prophylaxis

Purpose: To evaluate the long-term brain metabolite changes on (1)H-MRS in acute lymphoblastic leukemia (ALL) patients who had intrathecal methotrexate (ITMTX) and cranial irradiation (CRT) for central nervous system (CNS) prophylaxis against CNS relapse. METHODS AND MATERIALS: Thirty-seven ALL patients (12 females, 25 males) with history of ITMTX and CRT for CNS prophylaxis were studied. Age ranges at the time of diagnosis and at magnetic resonance examination were 0.8-13 years and 12-27 years, respectively. The interval since diagnosis was 5.6-19 years. T2-weighted and gradient-recalled echo (GRE) magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy ((1)H-MRS) were performed to assess brain injury. RESULTS: On MRI, 3 leukoencephalopathy (LEP) and 1 infarct were detected. Twenty-two patients had evidence of hemosiderin. On (1)H-MRS no statistically significant difference in choline (Cho)/creatine (Cr) and N-acetylaspartate (NAA)/Cr was associated with LEP. A lower Cho/Cr (p = 0.006) and NAA/Cr (p = 0.078) was observed in brains with hemosiderin. Linear-regression analysis showed no statistically significant relationship between NAA/Cr or Cho/Cr with age at diagnosis, but there was a statistically significant decreasing trend of NAA/Cr and Cho/Cr with the interval since diagnosis. CONCLUSION: Long-term brain injury in ALL survivors after CNS prophylaxis with ITMTX and CRT was reflected by decreasing NAA/Cr and Cho/Cr with the interval since diagnosis. The lower Cho/Cr associated with hemosiderin but not LEP suggested a different pathophysiology for these brain lesions.     

Proton magnetic resonance spectroscopy in immunocompetent patients with primary central nervous system lymphoma

Background: Magnetic resonance spectroscopy imaging (MRSI) non-invasively evaluates the metabolic profile of normal and abnormal brain tissue. Primary central nervous system lymphoma (PCNSL) is a highly aggressive tumor responsive to high-dose methotrexate based regimens. Patients often have complete responses but relapses are common. We characterized the MR spectra of PCNSL patients, correlated MRSI with MRI and evaluated whether early recurrence could be detected by MRSI.Methods: Patients with PCNSL had multi-voxel MRSI before, during, and after treatment. The region of interest was defined using axial FLAIR images. Metabolites assessed were N-acetyl-aspartate (NAA), choline (Cho), creatine (Cr), lipid, and lactate. Ratios of Cho/Cr, NAA/Cho, and NAA/Cr were calculated and correlated with MRI. Overall survival (OS), progression free survival (PFS), and relative risks of each of the ratios were determined.Results: MRSI was performed on 11 men and seven women; median age of 59. Sixty-seven MRSI studies were performed, 17 baseline and 48 follow-up studies. Median ratios in 16 pretreated patients were Cho/Cr-1.90, NAA/Cho-0.39, and NAA/Cr-1.27. Two patients had lipid at baseline, five had lactate and two had both. MRSI correlated with tumor response or progression on MRI; in three patients MRSI suggested disease progression prior to changes on MRI. Univariate analysis of metabolite ratios, lipid, and lactate revealed that none significantly affected PFS or OS. Kaplan–Meier analysis of the presence or absence of lipid, lactate or both revealed a trend for increased PFS.Conclusion: MRSI and MRI correlate with tumor response or progression and may allow early detection of disease recurrence. The presence or absence of lipid and/or lactate may have prognostic significance. Further research using MRSI needs to be done to validate our findings and determine the role of MRSI in PCNSL.Presented in part at the 1999 Annual Meeting of the American Academy of Neurology; April 12, 1999.     

Dynamic 1H-MRS assessment of brain tumors: A novel approach for differential diagnosis of glioma

Purpose

To determine whether the changes of [Cho/NAA] ratio in patients with glioma, measured by dynamic ¹H-MRS can be used to differentiate between high-grade and low-grade gliomas.

Materials and Methods

This prospective study was approved by the institutional ethics committee. Written informed consent was obtained. Forty-nine patients with biopsy-proven glioma and 20 normal control subjects were recruited in this study. The maximum [Cho/NAA] ratios, acquired at 0 min, and at 6 min, were calculated and assessed from volume of interests (VOI) in the tumor areas and in the surrounding normal tissue for each patient. Absolute difference in the [Cho/NAA] ratios, from MRS acquired at 0 and 6 min, in high-grade glioma, low-grade glioma, and control subjects were compared.

Results

The maximum [Cho/NAA] ratio acquired from the tumor area at the 0 min is 6.08 ± 2.02, which was significantly different (p = .017) from that acquired after 6 min, 4.87 ± 2.13. The [Cho/NAA] ratio from the surrounding normal tissue area did not change significantly from spectra acquired at different times (0 min, 6 min). Absolute difference in [Cho/NAA] ratios acquired at 0 and 6 min time points were significantly higher (P < 0.001) in high-grade glioma (= 3.86 ± 3.31) than in low-grade glioma (= 0.81 ± 0.90), and control subjects (0.061 ± 0.026, P = 0.000), while there was no significantly difference in low-grade glioma and control subjects.

Conclusions

Dynamic ¹H-MRS can be useful for differential diagnosis between high-grade and low-grade gliomas as well as insight into the heterogeneity within the tumor.     

Metabolic assessment of monofocal acute inflammatory demyelination using MR spectroscopy and <Superscript>11</Superscript>C-methionine-, <Superscript>11</Superscript>C-choline-, and <Superscript>18</Superscript>F-fluorodeoxyglucose-PET

Monofocal acute inflammatory demyelination (MAID), which is observable by CT and MRI as a well-enhanced mass lesion with prominent perifocal edema, is very similar to malignant gliomas radiologically, making differential diagnosis of the two pathologies difficult. The aim of this study was to assess the different metabolic activities between MAID and malignant gliomas by MRS, methionine-PET, choline-PET, and FDG-PET. Six patients with MAID underwent methionine, choline, and FDG-PET, and 4 of the patients also underwent magnetic resonance spectroscopy (MRS). The images obtained from these patients were compared with the corresponding images of 19 anaplastic astrocytomas (AA) and 21 glioblastomas (GBM). The mean choline/creatine ratio of MAID was significantly lower than that of GBM. There were no significant differences in the mean NAA/creatine and lactate/creatine ratios among these pathologies. The methionine T/N ratio of MAID was significantly lower than those of AA and GBM. The choline T/N ratio of MAID was significantly lower than that of GBM. There were no significant differences in the FDG T/N ratios among these pathologies. These results demonstrate that the metabolic activity of MAID significantly differs in part from that of malignant gliomas. Combined PET and MRS neuroimaging examinations may be useful for differential diagnosis of these pathologies.     

Non-invasive Characterization of Brain Tumor by in-vivo Proton Magnetic Resonance Spectroscopy

We studied the feasibility of characterizing brain tumor tissue by localized proton magnetic resonance spectroscopy (¹H-MRS), Twenty-six newly diagnosed tumors were examined by in-vivo , ¹H-MRS. The NAA (N-acetylaspartate)/Cho (choline) ratio of Grade 2 astrocytoma was higher than that of Grade 4. The Cho/Cr (creatine and phosphocreatine) ratio of meningioma was considerably higher than that of glioma of all grades. We have experienced only two cases of ependymoma and the Cho/Cr ratios of both were lower than that of glioma. It seems likely that ¹H-MRS can be used to differentiate Grade 2 from Grade 4 in most cases of astrocytoma based on the NAA/Cho ratio, though a few cases will overlap. Meningioma can be distingulshed easily from glioma, and the results of our study suggest that ependymoma shows a characteristic pattern on ¹H-MRS, different from those of other brain tumors.     

申捷对放疗前后脑照射野内N-乙酰天门冬氨酸、胆碱及肌酸含量的影响

目的：利用磁共振波谱技术检测应用申捷（单唾液酸四己糖神经节苷钠）及放疗前后脑组织内N-乙酰天门冬氨酸、胆碱及肌酸含量变化,探讨申捷在预防及治疗早期放射性脑损伤中的作用。方法：将鼻咽癌患者随机分为两组,对照组给予放疗﹢肾上腺皮质激素;治疗组：放疗﹢肾上腺皮质激素﹢申捷。申捷为每日100mg,加入到生理盐水或5％葡萄糖水中静脉滴注。两组均于放疗前及放疗后2个月行颅脑MRI、MRS检查,并测定NAA/Cr和Cho/Cr值。结果：放疗结束后双颞叶NAA/Cr在对照组中明显下降（ P＝0.022）,在治疗组中无明显下降（P＝0.949）。而Cho/Cr在对照组中明显升高（P＝0.031）,在治疗组中无明显升高（P     

Magnetic resonance spectroscopy as an early indicator of response to anti-angiogenic therapy in patients with recurrent glioblastoma: RTOG 0625/ACRIN 6677

Background

The prognosis for patients with recurrent glioblastoma remains poor. The purpose of this study was to assess the potential role of MR spectroscopy as an early indicator of response to anti-angiogenic therapy.

Methods

Thirteen patients with recurrent glioblastoma were enrolled in RTOG 0625/ACRIN 6677, a prospective multicenter trial in which bevacizumab was used in combination with either temozolomide or irinotecan. Patients were scanned prior to treatment and at specific timepoints during the treatment regimen. Postcontrast T1-weighted MRI was used to assess 6-month progression-free survival. Spectra from the enhancing tumor and peritumoral regions were defined on the postcontrast T1-weighted images. Changes in the concentration ratios of n-acetylaspartate/creatine (NAA/Cr), choline-containing compounds (Cho)/Cr, and NAA/Cho were quantified in comparison with pretreatment values.

Results

NAA/Cho levels increased and Cho/Cr levels decreased within enhancing tumor at 2 weeks relative to pretreatment levels (P = .048 and P = .016, respectively), suggesting a possible antitumor effect of bevacizumab with cytotoxic chemotherapy. Nine of the 13 patients were alive and progression free at 6 months. Analysis of receiver operating characteristic curves for NAA/Cho changes in tumor at 8 weeks revealed higher levels in patients progression free at 6 months (area under the curve = 0.85), suggesting that NAA/Cho is associated with treatment response. Similar results were observed for receiver operating characteristic curve analyses against 1-year survival. In addition, decreased Cho/Cr and increased NAA/Cr and NAA/Cho in tumor periphery at 16 weeks posttreatment were associated with both 6-month progression-free survival and 1-year survival.

Conclusion

Changes in NAA and Cho by MR spectroscopy may potentially be useful as imaging biomarkers in assessing response to anti-angiogenic treatment.     

1HMRS在鉴别脑内单发环形强化病变中的应用

目的：分析3.0T氢质子磁共振波谱成像（1HMRS）在鉴别脑内单发环形强化病变中的应用。方法应用PHILIPS 3.0T磁共振扫描仪对65例在MRI增强扫描时表现为脑内单发环形强化病变的患者治疗前行1HMRS扫描,经病理证实或临床确诊为30例高级别胶质瘤、23例单发脑转移瘤和12例脑脓肿。分别测量病灶中心及周围水肿区的NAA、Cho及Cr峰的峰下面积,计算NAA/Cr、Cho/Cr、NAA/Cho比值,并记录病灶中心Lac和Lip峰是否出现。对各参数值进行统计学分析,明确其对鉴别三种疾病的诊断价值。结果病灶中心的Cho值胶质瘤﹥转移瘤﹥脑脓肿;Cho/Cr值胶质瘤﹥脑脓肿（P﹤0.05）;NAA/Cho值脑脓肿﹥转移瘤﹥高级别胶质瘤;NAA及NAA/Cr在三组之间差异均无统计学意义。周围水肿区的NAA/Cr转移瘤组﹥脑脓肿组;Cho/Cr比值差异有显著统计学意义（P﹤0.001）,胶质瘤组﹥脑脓肿组﹥转移瘤组,高级别胶质瘤组明显高于单发脑转移瘤组（P=0.000）且Cho/Cr临界值为1.5650时诊断为高级别胶质瘤的敏感度为73.3%,特异度为94.4%,ROC曲线下面积为0.921。周围水肿区NAA/Cho差异有显著统计学意义（P﹤0.001）,转移瘤组高于胶质瘤组和脑脓肿组。高级别胶质瘤Lip峰出现率低于转移瘤和脑脓肿,转移瘤和脑脓肿组间比较差异无统计学意义。结论1HMRS可用于鉴别脑内单发环形强化病变,病灶中心的NAA/Cho和周围水肿区的Cho/Cr比值对高级别胶质瘤、单发脑转移瘤和脑脓肿的鉴别诊断具有重要意义。     

脑胶质瘤复发与放射性脑损伤的鉴别诊断

目的 探讨胶质瘤复发与放射性脑损伤之间的鉴别诊断方法。方法 选择胶质瘤复发和放射性脑损伤患者33例,获取患者症状和体征等临床资料,均进行MRS检查。结果 胶质瘤复发与放射性脑损伤患者的临床表现基本相同,未见显著性差异;胶质瘤复发患者的Cho/Cr、Cho/NAA比值显著高于放射性脑损伤患者,差异具有统计学意义。结论 MRS检查对于鉴别脑胶质瘤复发与放射性脑损伤存在应用价值。