Gadolinium-DTPA in MR imaging of glioblastomas and intracranial metastases

In 14 patients with the diagnosis of glioblastoma (n = 7) or intracranial metastases (n = 7), magnetic resonance (MR) imaging was performed using a variety of spin-echo (SE) pulse sequences before and after intravenous injection of 0.1 mmol gadolinium-DTPA (Gd-DTPA) per kilogram of body weight. In 10 patients, tumor tissue could not be adequately differentiated from perifocal edema on unenhanced scans with any of the applied pulse sequences. In four cases of intracranial metastases, poor differentiation between tumor and perifocal edema was possible in T2-weighted (SE 1600/70 and SE 1600/105) unenhanced scans. After administration of Gd-DTPA, tumor tissue showed marked contrast enhancement, and tumor delineation was consistently possible on SE 800/35 images. Tumor tissue could be differentiated from perifocal edema on SE 800/70 scans. Gd-DTPA is likely to increase the potential of MR imaging and refine the evaluation of glioblastomas and intracerebral metastases.     

Differentiation of hepatic hemangiomas from metastases by dynamic contrast-enhanced MR imaging

Twenty-nine patients with hepatic hemangiomas (n = 14) and hepatic metastases (n = 15) underwent magnetic resonance (MR) imaging prior to and after an intravenous bolus injection of Gd-diethylenetriamine pentaacetic acid (0.2 mmol/kg). Before contrast application, a T2-weighted spin echo sequence (SE 1,600/105) and a T1-weighted gradient echo sequence (GE 315/14/90 degrees pulse angle) were performed. Beginning with injection of the contrast agent, a dynamic study was conducted for 10 min using a moderately T1-weighted gradient echo sequence (GE 40/14/40 degrees) with an acquisition time of 10.2 s per image. Delayed (11 min) and late (60 min) postcontrast images were obtained using a T1-weighted sequence (GE 315/14/90 degrees). In the dynamic study (0-10 min) the hemangiomas were characterized by peripheral contrast enhancement and a subsequent hyperintense fill-in. The metastases showed very mixed patterns of enhancement after contrast administration, and their signal intensity remained low compared with that of the hepatic tissue. In the delayed postcontrast examination (11 min) the hemangiomas had a very high and homogeneous signal intensity and the metastases were characterized by an inhomogeneous, hypointense to isointense signal. The contrast between tumor and liver [signal-difference-to-noise ratio (SD/N)] was higher for all hemangiomas than it was for the metastases. In the T2-weighted precontrast examination, on the other hand, five hemangiomas and seven metastases showed an overlap in the SD/N. The late postcontrast images (60 min) did not yield any further diagnostic information. We conclude that the combination of a dynamic MR study with delayed postcontrast T1-weighted imaging is a useful method of diagnosing hepatic hemangiomas.     

Detection of hepatic metastases by proton spectroscopic imaging. Work in progress

Fourteen patients with hepatic metastases underwent magnetic resonance (MR) imaging using both the conventional spin-echo (SE) technique and the opposed phase of the proton spectroscopic imaging method. The opposed image showed more lesions than the conventional SE image in five patients and provided better contrast between the liver parenchyma and metastases in two patients. Four of these seven patients had associated fatty infiltration of the liver. When compared with the computed tomography (CT) scan, the opposed image either showed more lesions or provided better contrast in six patients, four of whom had fatty infiltration. More significantly, the MR image showed several 1-cm lesions not shown by the CT scan in one patient. Our study discloses the possible explanations for the increased sensitivity of the opposed image in detecting hepatic metastases.     

CT and MR imaging of advanced Zollinger-Ellison syndrome

The CT and magnetic resonance (MR) findings in 13 patients with advanced Zollinger-Ellison syndrome are described. In eight patients (62%) one or more primary tumors were found with both methods. All patients with proven liver metastases (n = 7) were identified by MR. Computed tomography was positive in six of these patients. Three patients with lymph node metastases were identified on CT and MR and one patient had bone metastases. Computed tomography and MR were inferior to selective arteriography in the detection of multiple lesions of the pancreas in a patient with multiple endocrine neoplasia-I syndrome. On the T1-weighted MR images, the primary tumors demonstrated no consistency with regard to their signal intensity relative to the adjacent pancreatic parenchyma. All gastrinomas had an increased relative signal intensity on the T2-weighted images with the exception of a calcified tumor. Liver and lymph node metastases had a low signal intensity on the T1-weighted images and an increased signal intensity on the T2-weighted images. The signal intensity of primary tumors and metastases was independent of size. In conclusion, MR was able to detect abnormalities based on its outstanding lesion/normal tissue contrast, whereas CT diagnosis was based mostly on contour distortion. For the current technique, MR is considered at least equal to CT.     

Contrast-enhanced MR imaging of malignant brain tumors

Magnetic resonance (MR) imaging was performed before and serially after intravenous injection of 1 mmol/kg gadolinium-DTPA (Schering) in 17 patients with clinical and histologic diagnosis of malignant cerebral tumors. There was a decrease of 1% in T1 and 10% in T2 in normal white matter and a decrease of 8% in T1 and 14% in T2 in normal gray matter. Contrast enhancement was observed in 16 of the 17 tumors. In the region of maximal enhancement a mean decrease of 16% in T1 was observed in low-grade gliomas, a mean decrease in T1 of 29% was seen in high-malignancy gliomas, and a mean decrease in T1 of 33% was observed in metastases. The decreases in T1 persisted for at least 50 min. In one case the central cystic region of the tumor displayed a decrease in T1 and T2. Measurements of signal intensity displayed maximal contrast enhancement with an IR 1500/500/44 sequence, much less with SE 1500/44, and least with SE 1500/80. Edema was observed on precontrast images in 14 cases, but satisfactory definition of the tumor-edema margin was only possible in four cases. After contrast enhancement this margin was defined in 10 cases. In four of the 17 cases areas of apparent "edema" seen before administration of Gd-DTPA displayed significant contrast enhancement and probably represented tumor infiltration. Comparison with CT showed a greater degree of contrast enhancement on MR images in eight cases, an equal degree in eight cases, and greater enhancement on CT in one case.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hepatic tumors: differentiation by transverse relaxation time (T2) of magnetic resonance imaging

Fifty-three patients who had hepatic tumors (24 hepatomas, ten metastases, and 19 cavernous hemangiomas) underwent MR imaging using a 0.35-T superconducting imager. The transverse relaxation time (T2) was calculated from a pair of spin echo images (repetition time [TR] of 1600 msec) with echo delay times (TE) of 35 and 70 msec. The computed T2 value was obtained in a fashion similar to that used to obtain CT numbers with region-of-interest cursors. The mean T2 was 59 +/- 9 msec in hepatomas, 64 +/- 15 msec in metastases, and 100 +/- 30 msec in hemangiomas. The difference between the T2 of hemangioma and that of liver malignancies was statistically significant (P less than .001); however, differentiation between hepatoma and metastases was not possible. The T2 was shorter than 80 msec in all 24 hepatomas and in nine of ten metastases, and was longer than 80 msec in 16 of 19 hemangiomas. Forty-nine of 53 cases (92%) were correctly classified when the borderline of T2 between hemangioma and hepatic malignancies was set at 80 msec. MR with T2 calculation was valuable in differentiating between hemangioma and hepatic malignancies.     

MR image contrast and relaxation times of solid tumors in the chest, abdomen, and pelvis

A retrospective study of 121 patients with tumors in the chest, abdomen, and pelvis was made to assess the degree of contrast between solid tumors and adjacent tissue on magnetic resonance (MR) spin echo (SE) images. Tumors examined were hepatomas (five patients), liver metastases (17), hemangiomas (seven), biliary carcinomas (eight), pancreatic carcinomas (five), renal tumors (15), adrenal tumors (eight), uterine tumors (17), bladder carcinomas (five), prostatic carcinomas (13), bone tumors (six), and lung carcinomas (15). A long repetition time (TR) and a long echo time (TE) were found the most useful to delineate tumors from liver, renal tumors from kidney, lung carcinoma from lung, pelvic tumors from muscle, and uterine tumors from the myometrium. A short TR and short TE provided the best contrast between tumors and fat and bone marrow. Therefore, for detection and staging of tumors, both a sequence with short TR and short TE and one with long TR and long TE are necessary. Pancreatic carcinomas were difficult to differentiate from liver and pancreas on all SE sequences used in the study. Contrast of adrenal tumors was independent of the sequence used. Some adrenal tumors were hypointense and some similar in intensity to the kidney. Further MR characterization of the tumors was limited.     

Dual-contrast MR imaging of liver cancer in rats

MR contrast agents increase hepatic tumor conspicuity, as measured in terms of contrast-to-noise (C/N) ratios. With an animal model of hepatic metastases from breast cancer, IV administration of Gd-DTPA (0.2 mmol/kg) shows a biphasic time response, transiently increasing the signal intensity of liver relative to tumor, with C/N ratio magnitudes increasing from -5.7 to -16.3 (SE 250/20); after a delay, the signal intensity of tumor increases relative to liver with a reversal of the C/N sign from negative to positive and an increase in the C/N magnitude to +25.0. IV administration of ferrite particles (0.05 mmol Fe/kg) shows a monophasic time response, increasing signal intensity of tumor relative to liver from +1.5 to +49.5 (SE 500/30). When both contrast agents were administered together (dual-contrast technique), the tumor-liver C/N magnitude reached a maximum of +67.8 (SE 500/30) 12 min after drug infusion. Analysis of individual contrast and noise factors contributing to this technique revealed a strong correlation between the signal intensity of liver and the signal intensity of ghost artifacts, which increase after administration of Gd-DTPA (r = .89) and decrease after administration of ferrite (r = 1.0). Dual-contrast imaging shows a synergistic addition of contrast and suppression of noise from ghost artifacts, maximizing the C/N and increasing the conspicuity of focal liver lesions.     

Magnetic resonance imaging of the adrenal gland]

Adrenal imaging was performed using magnetic resonance (MR) was in 100 patients who had no clinical or biochemical evidence of adrenal abnormality and in 19 patients with 24 adrenal lesions (adenoma in 5, hyperplasia in 2, metastasis in 5, (lung cancer in 1, hepatoma in 4) adrenal cancer in 1, pheochromocytoma in 3, neuroblastoma in 3). Normal adrenal glands showed intermediate intensity between muscle and liver, and were detected in over 90% of cases on T1-weighted images (T1-weighted SE, inversion recovery). Adenomas and hyperplasias had the same intensity as normal glands. Medullary masses showed extreme hyperintensity on T2-weighted images and could be differentiated from cortical masses. Neuroblastomas were detected as hyperintense tumors with intratumoral hemorrhage and necrosis on T2-weighted MR images. Metastatic adrenal tumors from lung cancer were hyperintense on T2-weighted images, while metastasis from hepatoma showed low intensity on the same pulse sequence. In diagnosing adrenal metastasis, we must compare and contrast the tumor intensity and structure with those of the primary lesions. MR is considered a useful modality in characterizing adrenal tissue.     

Dynamic sequential MR imaging of focal liver lesions: initial experience in 22 patients at 1.5 T

The feasibility of dynamic sequential magnetic resonance (MR) imaging of focal hepatic lesions using Gd-diethylenetriamine pentaacetic acid (DTPA) was evaluated in this study. Three patients with hepatocellular carcinoma, 12 patients with metastases, and 7 patients with hemangiomas were studied with pre- and postcontrast multislice spin echo (SE) images using a repetition time of 500 ms and an echo time of 15 ms. The dynamic distribution phase of Gd-DTPA (0.1 mmol/kg) was investigated by using a sequential, transverse partial flip imaging sequence [fast low angle shot (FLASH)] before and after intravenous administration of Gd-DTPA. The lesion-liver contrast-to-noise ratio showed a great variability in patients with metastases and was significantly improved following administration of Gd-DTPA in patients with hemangiomas, two patients with hepatocellular carcinoma, and eight patients with metastases both on FLASH and SE images. Hemangiomas appeared darker than liver parenchyma on precontrast SE and FLASH images, increasingly enhanced over 5 min postinjection (pi) on FLASH images, and were still greatly enhanced at 10 min pi on SE images. During the dynamic sequential image acquisition the contrast enhancement of hemangiomas was significantly different from the enhancement observed in malignant lesions. The results of this study indicate the clinical potential of dynamic sequential imaging for the MR assessment of focal hepatic lesions.     

Gd-BOPTA/Dimeg: experimental disease imaging.

The novel tissue-specific contrast agent, Gd-BOPTA/Dimeg, was tested in MR imaging of experimental focal liver disease and of acute myocardial ischemia in rats. Directly implanted liver tumors and blood-borne metastases were used as models for focal liver disease and occlusion of the lower anterior descending coronary artery as model for acute ischemia. The studies with implanted tumors, at a dose level of 250 mumol/kg, showed a very high (370%) and persistent (greater than 2 h) increase in the tumor-liver contrast-to-noise ratio (CNR), owing to selective enhancement of normal liver parenchyma signal intensity. While all blood-borne metastases showed a similar late CNR enhancement, some of them experienced early contrast loss due to transient signal intensity enhancement. In myocardial imaging, Gd-BOPTA/Dimeg produced a signal intensity enhancement in normal myocardium and an injured area-normal area CNR enhancement which were both much stronger and more persistent than those produced by Gd-DTPA/Dimeg.     

脊柱转移瘤的MR诊断

目的 探讨脊柱转移瘤的MR诊断。方法 回顾性分析120例脊柱转移瘤的MR表现。结果 脊柱转移瘤灶的异常MR表现为：（1）信号异常,在T1WI上,112例（93.3%)呈低信号,8例（6.7%)为等或混杂的信号,在T2WI上,89例（74.1%)呈稍高信号,33例（27.5%)为低或混杂信号;（2）病灶可呈跳跃式破坏,椎体附件受累,出现椎旁软组织肿块,但椎间隙保持完整;（3）伴发椎体压缩性骨折的病灶可呈“楔形”、“盘状”或“倒楔形”。脂肪抑制增强扫描可显示病变范围并发现平扫中未能发现的病变。结论 MRI是诊断脊柱转移瘤的可靠而重要的手段。     

Focal liver lesions: MR imaging with Mn-DPDP--initial clinical results in 40 patients.

Manganese (II) N,N'-dipyridoxylethylenediamine-N,N'-diacetate-5,5'-bis(phosphate) (DPDP) was evaluated as a contrast agent for magnetic resonance (MR) imaging (1.5 T) of focal liver lesions in 40 patients. Doses of 5 and 10 mumol/kg were administered intravenously. Mn-DPDP-enhanced T1-weighted images were compared quantitatively and subjectively with standard T1- and T2-weighted nonenhanced images. Use of Mn-DPDP resulted in a statistically significant increase in signal intensity of liver parenchyma in T1-weighted images at both doses. No enhancement was seen in metastases, cholangiocarcinomas, or lymphomas, while all hepatocellular carcinomas were enhanced. Enhancement was seen in focal nodular hyperplasia and in regenerative nodules. The lesion-to-liver contrast in Mn-DPDP-enhanced gradient-recalled-echo images was superior to that of all precontrast images (P less than .01). The number of nonenhancing malignant liver lesions detected in spin-echo (SE) images was increased (272 in T2-weighted SE images vs 390 in T1-weighted Mn-DPDP-enhanced SE images). Image interpretation (eg, visualization and demarcation of the lesions) was markedly better in Mn-DPDP-enhanced images than in all precontrast images (P less than .001).     

Magnetic resonance in hepatic lesions. Experience with a 1.5-T magnetic field

Forty-one patients with histologically proven hepatic lesions (6 cysts, 6 hemangiomas, 8 hepatomas, 19 metastases and 2 negative cases) were studied with Magnetic Resonance (MR) imaging at 1.5 T, and with US and CT. This prospective study was aimed at evaluating: the comparative accuracy of MR, US and CT; the sensitivity and specificity of spin-echo (SE) vs FISP pulse sequences; the efficacy of T1 and T2 relaxation time values in differentiating hemangiomas from hepatomas and metastases. MR diagnostic accuracy was 94.7% vs 89.4% of CT and 84.2% of US. FISP sequences provided 60% sensitivity and 66% specificity. T2 relaxation time values were statistically significant (p less than 0.05) in differentiating hemangiomas (T2 range: 80.9-218.9 ms) from hepatomas (T2 range: 59.4-83.2 ms). The differences in mean T2 values between hemangiomas and metastases (T2 range 54.3-177.3 ms) were not statistically significant (p greater than 0.25).     

Detection of hepatic metastases with MR imaging: spin-echo vs phase-contrast pulse sequences at 0.6 T

The purpose of this study was to compare the sensitivity of T1-weighted and T2-weighted spin-echo (SE) pulse sequences with T2-weighted phase-contrast (PC) imaging techniques for the detection of hepatic metastases. Pulse-sequences performance was evaluated in 52 consecutive patients with 88 hepatic metastases who underwent MR imaging at 0.6 T. Lesion-liver contrast-to-noise ratios (CNR) on SE 260/14 (-12.4 +/- 6.7) and PC 2350/60 (+10.8 +/- 4.2) images were significantly (p less than .05) greater than on SE 2350/60 (+ 7.8 +/- 3.9), SE 2350/120 (+8.1 +/- 4.8), SE 2350/180 (+7.9 +/- 4.5), and PC 2350/30 (+4.6 +/- 2.9) images. Sensitivity for detection of 88 individual metastases was comparable on SE 260/14 (78 of 88 patients) and PC 2350/60 (81 of 88 patients) images and was significantly (p less than .05) greater than on in-phase T2-weighted SE images (TE = 60, 70 of 88 patients; TE = 120, 69 of 88 patients; TE = 180, 65 of 88 patients). Histologic analysis of tumor-free liver showed fatty change in 11 of 13 specimens available for pathologic evaluation. In all 11 of those patients, PC images increased tumor-liver contrast in comparison with the in-phase SE images. This analysis suggests that for detection of hepatic metastases at midfield strengths, the T1-weighted, short TR/short TE (SE 260/14) and the T2-weighted, phase-contrast (PC 2350/60) pulse sequences offer comparable performance.     

Delineation of gliomas with magnetic resonance imaging using Gd-DTPA in comparison with computed tomography and positron emission tomography

Fourteen patients with cerebral gliomas were investigated by MR imaging using Gd-DTPA (Magnevist), CT with the contrast agent iohexol (Omnipaque) and, as a reference, positron emission tomography (PET) using 11C-L-methionine. Tumour areas with disruption of the blood-brain-barrier (BBB) as seen on MR and CT were compared with areas increased accumulation of methionine in PET. There were 6 patients with high-grade astrocytoma (grade III-IV), 5 with low-grade astrocytoma (grade I-II) and 3 with oligodendroglioma. In 4 high-grade tumours, PET showed a larger tumour or tumour tissue in additional areas, compared with enhancement on MR and CT, while in 2 cases the tumour extension was similar in the three modalities. In the low grade tumour group, the findings on PET differed from those on post-contrast MR or CT in 7 cases. In 3 of these cases, no disruption of the BBB was seen either on MR or on CT. In 2 of our 14 patients CT showed larger enhancement extension than MR and in 2 cases MR was superior to CT in this respect. The enhancement intensity was higher on MR in 4 patients and on CT in 2 patients. No definite difference in the delineation of tumour tissue between the T1 weighted SE sequences was found. The gradient echo sequences FLASH and FISP gave limited information that was less than that provided by the T1 weighted SE sequences. A greater increase in signal intensity in T1 weighted images was usually seen 5 min post-contrast in the high-grade tumours than in the low-grade ones.     

Uptake of mangafodipir trisodium in liver metastases from endocrine tumors

The purpose of the study was to investigate retrospectively whether mangafodipir trisodium (MnDPDP) can enhance the liver metastases from endocrine tumors. Thirteen patients with endocrine tumors and liver metastases underwent T1-weighted spin-echo (SE) and turbo gradient-echo (GRE) MRI conducted before and 20 to 60 minutes after iv infusion of MnDPDP. Additional 24-hour-delay scans were performed in 8 of 13 patients. MR signal intensity (SI) was measured in liver parenchyma and metastases, which was then related to that of paraspinal muscle. A total of 30 lesions on precontrast and postcontrast images and 18 lesions on 24-hour-delay images were measured. An enhancement by 49% in SE and 40% in GRE images (P = .0001) was observed in tumor tissues after MnDPDP infusion. In 24-hour-delay images, the SI of the lesions remained relatively high, but in liver parenchyma, it decreased significantly, and the tumor-liver tissue contrast was reduced.     

Short TI inversion-recovery imaging of the liver: pulse-sequence optimization and comparison with spin-echo imaging

Magnitude-reconstructed short inversion-time (TI) inversion-recovery (IR) sequences have the advantage of reducing the signal of fat while providing additive T1 and T2 contrast. A double-echo short TI IR sequence was implemented to offer different degrees of T1- and T2-dependent image contrast. In 50 consecutive patients with proved liver tumors (30 metastases, 13 hemangiomas, seven other primary liver tumors), images obtained with a double-echo IR sequence at a repetition time (TR) of 1,500 msec, echo time (TE) of 30 and 60 msec, and TI of 80 msec (TR/TE/TI = 1,500/30, 60/80) were compared with those obtained with spin-echo (SE) sequences at a TR of 275 msec and a TE of 14 msec (TR/TE = 275/14) and 2,350/60, 120, 180. Metastases-liver contrast-to-noise ratios were highest at SE 275/14, followed by IR 1,500/30/80 and SE 2,350/180. IR 1,500/30/80 and SE 275/14 sequences consistently showed higher sensitivity for the detection of metastases than T2-weighted SE sequences. Differential diagnosis of benign and malignant lesions was more reliable with T2-weighted SE sequences than T2-weighted short TI IR sequences.     

Hepatic metastases: diffusion-weighted sensitivity-encoding versus SPIO-enhanced MR imaging

PURPOSE: To retrospectively compare accuracy of diffusion-weighted (DW) single-shot echo-planar imaging with sensitivity encoding (SENSE) with that of superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging in the evaluation of hepatic metastases due to extrahepatic malignancies. MATERIALS AND METHODS: Patients provided informed consent; ethics committee approval was not required. The data of 24 patients (16 men, eight women; age range, 41-68 years; mean age, 61.9 years) with 40 resected hepatic metastases were retrospectively reviewed. Before SPIO administration, DW SENSE imaging and T2-weighted fast spin-echo (SE) and T1-weighted dual-echo fast field-echo (FFE) MR imaging were performed. After SPIO administration, T2-weighted fast SE, T1-weighted dual-echo, and T2*-weighted FFE MR examinations were performed. Images were divided into two sets: The SPIO-enhanced MR image set consisted of pre- and postcontrast T2-weighted fast SE and dual-echo T1-weighted FFE images and postcontrast T2*-weighted FFE images. The DW SENSE image set included DW SENSE images and precontrast T2-weighted fast SE and dual-echo T1-weighted FFE images. Three radiologists individually interpreted these images and sorted the confidence levels for presence of hepatic metastasis in each section into five grades. Area under the receiver operating characteristic (ROC) curve (A(z)) was calculated for each image set. RESULTS: Hepatic metastases showed higher signal intensity on DW SENSE images than on T2-weighted fast SE images. Conversely, signals from vessels and cysts were suppressed with DW SENSE imaging. ROC analysis showed higher A(z) values when the DW SENSE image set was interpreted (0.90) than when the SPIO-enhanced MR image set was interpreted (0.81). The sensitivity and specificity, respectively, of total cases were 0.66 and 0.90, for the SPIO-enhanced MR image set and 0.82 and 0.94 for the DW SENSE image set. During SPIO-enhanced MR image interpretation, lesions 1 cm in diameter or smaller showed significantly lower sensitivity than lesions larger than 1 cm in diameter. During both interpretation sessions, left lobe lesions showed significantly lower sensitivity than right lobe lesions. CONCLUSION: Combined reading of DW SENSE images and T2-weighted fast SE and dual-echo T1-weighted FFE MR images showed higher accuracy in the detection of hepatic metastases than did reading of SPIO-enhanced MR images.     

Clinical application of 31P MRS to malignant liver tumors--with an emphasis on evaluation of response to therapy]

Malignant liver tumors in 19 cases (13 hepatomas and 6 metastatic tumors) were studied by 31P magnetic resonance (MR) spectroscopy. Five healthy volunteers were also studied. Volume localization was performed using the ISIS sequence. Compared with normal liver, the MR spectra of malignant tumors showed an elevated phosphomonoester (PME) peak relative to beta ATP (p less than 0.005), and tumors were slightly alkaline (pH 7.32 +/- 0.08) before therapy. Nine cases of hepatomas responding to chemoembolization showed extremely reduced signal intensity of spectra. Tumor pH was compared before and after therapy in four cases that showed good response to therapy, and was elevated in all of them. Three metastatic tumors with good response showed reductions in PME and ATP after therapy. MR spectroscopy with adequate localization technique is useful in demonstrating the response of malignant tumors to therapy.