Cost-effectiveness of high-dose MR contrast studies in the evaluation of brain metastases.

PURPOSETo investigate the cost-effectiveness of high-dose MR contrast studies in the management of brain metastases.METHODSDuring the phase III clinical trial of high-dose contrast studies (0.3 mmol/kg), 11 of 27 patients were judged by the reviewers to have potential treatment changes based on the additional information provided by the high-dose studies. We retrospectively evaluated how many of these 27 patients had actual treatment changes because of the results of the high-dose study. Using the fee schedule at our institution, the cost-effectiveness was analyzed based on the cost savings from treatment changes and the additional expense of implementing the high-dose studies.RESULTSA total of 3 craniotomies ($22,800 each) and 2 aggressive courses of radiation therapy ($1122 each) were avoided in 4 patients because of the additional lesions detected by the high-dose studies. This resulted in a treatment cost savings of $70,644. The extra expense for implementing the high-dose study is $9126 for a single injection in all 27 patients, $9295 for 2 separate injections completed in 1 visit in the 11 patients, and $11,154 for 2 separate injections completed in 2 separate visits. The cost savings in management (diagnosis and treatment) therefore ranged from $59,490 to $61,518 for all patients and from $2203 to $2278 per patient.CONCLUSIONBased on our limited data, the high-dose study seems to impact positively on the cost-effectiveness in the management of brain metastases. However, because our study had limitations, our results need to be confirmed with a larger patient population and a more standardized treatment approach and fee schedule.     

Phase III multicenter trial of high-dose gadoteridol in MR evaluation of brain metastases.

PURPOSETo assess the efficacy and safety profile of high-dose (0.3 mmol/kg cumulative dose) gadoteridol in patients with suspected central nervous system metastatic disease.METHODSWe studied 67 patients using an incremental-dose technique. Patient monitoring included a medical history, physical examination, vital signs, and extensive laboratory tests within 24 hours before and after the MR examination. Precontrast T1- and T2-weighted spin-echo studies were performed, followed by intravenous injection of 0.1 mmol/kg of gadoteridol. T1-weighted images were acquired immediately after and at 10 and 20 minutes after injection. At 30 minutes an additional 0.2 mmol/kg of gadoteridol was administered (0.3-mmol/kg cumulative dose), and T1-weighted images were acquired. Cases demonstrating abnormal MR findings were assessed for efficacy by unblinded and blinded reviewers and were analyzed quantitatively.RESULTSThree adverse effects in two patients were considered to be related to gadoteridol administration. No adverse effects were serious; all self-resolved. Forty-nine cases showed abnormal MR findings and were included in the efficacy analysis. A significantly greater number of lesions was seen on the high-dose as opposed to the standard-dose images. Blinded and unblinded readers identified 5 and 8 patients, respectively, with solitary lesions on standard-dose examination and multiple lesions on high-dose examination. Two patients who had normal standard-dose findings had lesions identified on high-dose studies. Quantitative analysis of 133 lesions in 45 patients demonstrated significant increases in lesion signal intensity on high-dose studies when compared with standard-dose studies.CONCLUSIONGadoteridol can be safely administered up to a cumulative dose of 0.3 mmol/kg. High-dose contrast studies provide improved lesion detectability and additional diagnostic information over studies performed in the same patients with a 0.1-mmol/kg dose and aid in patient diagnosis and treatment. High-dose gadoteridol study may facilitate the care of patients with suspected central nervous system metastasis.     

脑转移瘤动态增强磁化率MR灌注成像特点的研究

目的研究治疗前不同来源脑转移瘤的动态增强磁化率(DSC)MR 灌注成像特点。方法对28例经病理或随访证实为脑转移瘤的患者行手术前 DSC MR 灌注成像扫描。分析 MR 灌注曲线及伪彩图像,测量肿瘤实质部分及瘤周水肿区最大相对脑血容积(rCBV)值及相应部位相对平均通过时间(rMTT)数值,并将所测量数值进行 t 检验分析,P<0.05为差异具有统计意义。结果不同来源脑转移瘤的 MR 灌注曲线、伪彩图像特点无明显差异。脑转移瘤肿瘤实质部分灌注程度与正常脑灰质相仿,瘤周水肿区表现为低灌注,两者的灌注时间均延长。12例来源于肺癌与5例来源于乳腺癌的脑转移瘤肿瘤实质部分的最大 rCBV 值(分别为272.5±34.3和210.8±59.4)及相应部位的 rMTT 数值(分别为117.7±4.3和105.2±21.3)之间以及两者瘤周水肿区 rCBV 值(分别为122.0±16.3和68.4±6.1)和 rMTT 值(分别为112.7±8.3和139.8±37.9)之间差异均无统计学意义(P>0.05)。结论不同来源脑转移瘤的 MR 灌注成像特点趋于一致。     

肿瘤软脑膜-蛛网膜转移的CT、MRI诊断

目的研究肿瘤软脑膜蛛网膜转移的ＣＴ、ＭＲＩ表现,并探讨两种检查方法对该病的诊断价值。方法回顾分析２１例肿瘤软脑膜蛛网膜转移的临床及影像学资料。病变经ＣＴ检查１６例,ＭＲＩ检查７例,其中经两种方法检查者２例。结果全部病例软脑膜蛛网膜下腔均出现病理性强化,其中１０例呈弥漫性,８例呈结节性,３例呈弥漫与结节混合性。弥漫性强化沿脑和脑干表面分布,并延伸入脑沟、脑池;结节性强化病灶数目１个或多个不等,直径０．２～３．０ｃｍ。病变见于基底脑池及相邻蛛网膜下腔者共１８例。伴室管膜结节性强化４例,天幕增厚强化１０例,脑积水１３例,合并脑内转移９例。结论增强ＣＴ和ＭＲＩ对病变的诊断具有重要临床意义,且ＭＲＩ优于ＣＴ。但两者在定性诊断上均有局限性。正确诊断有赖于结合临床资料和影像征象的综合分析     

Whole-body MR imaging: evaluation of patients for metastases

PURPOSE: To compare the results of whole-body magnetic resonance (MR) imaging with staging based on computed tomographic (CT), dedicated MR imaging, and nuclear scintigraphic results as standard of reference. MATERIALS AND METHODS: Fifty-one patients with known malignant tumors were included in the study. Patients were placed on a rolling table platform capable of moving the patient rapidly through the isocenter of the magnet bore. The thorax and the abdomen were imaged by using fast breath-hold T2-weighted sequences in the transverse plane. After intravenous administration of a paramagnetic contrast agent, three-dimensional gradient-echo data sets were collected in five stations and covered the body from the skull to the knees. Location and size of cerebral, pulmonary, hepatic, and osseous metastases were documented by two experienced radiologists. Whole-body MR imaging findings were compared with results obtained at skeletal scintigraphy, CT, and dedicated MR imaging. RESULTS: The mean examination time for whole-body MR imaging was 14.5 minutes. All cerebral, pulmonary, and hepatic metastases greater than 6 mm in diameter could be identified with whole-body MR imaging. Small pulmonary metastases were missed with MR imaging, which did not change therapeutic strategies, but MR imaging depicted a single hepatic metastasis that was missed with CT. Skeletal scintigraphy depicted osseous metastases in 21 patients, whereas whole-body MR imaging revealed osseous metastases in 24 patients. The additional osseous metastases seen with MR imaging were confirmed at follow-up examinations but did not result in a change in therapy. Whole-body MR imaging performed on a per-patient basis revealed sensitivity and specificity values of 100%. CONCLUSION: Whole-body MR imaging for the evaluation of metastases compared well with the reference techniques for cerebral, pulmonary, and hepatic lesions. Whole-body MR imaging was more sensitive in the detection of hepatic and osseous metastases than were the reference techniques.     

Intraparenchymal brain metastases: MR imaging versus contrast-enhanced CT

Prospective and retrospective studies of 75 patients were performed to assess the sensitivities of magnetic resonance (MR) imaging and computed tomography (CT) in the evaluation of suspected intraparenchymal brain metastases. The findings on MR images were equivalent to those on CT scans in 49 of the 75 patients; the remaining findings were discordant in 26 patients, and neither MR imaging nor CT was consistently superior. MR imaging demonstrated more metastases in nine of these 26 patients. However, contrast material-enhanced CT scans were superior in lesion depiction in eight of the 26 patients. Large enhanced lesions that were nearly isointense on MR images were seen well on CT scans. In several cases in which results were discordant, gadolinium-diethylenetriaminepentaacetic acid (DTPA)-enhanced MR images were obtained, and this agent behaved similarly to iodinated contrast agents. If indicated clinically, such as before surgery for a single metastasis, the authors perform both MR imaging and contrast-enhanced CT. Gd-DTPA-enhanced MR imaging may prove to be the method of choice for depiction of intraparenchymal metastases.     

Phases IB and II multidose trial of gadolinium texaphyrin, a radiation sensitizer detectable at MR imaging: preliminary results in brain metastases.

PURPOSE: To evaluate magnetic resonance (MR) imaging results after administration of gadolinium texaphyrin, a tumor-selective radiation sensitizer that is detectable at MR imaging, and to determine an appropriate intravenous dose of gadolinium texaphyrin for repeated injections during radiation therapy, the dose-limiting toxicity of reiterated doses of gadolinium texaphyrin, the maximal tolerated dose, the biolocalization of gadolinium texaphyrin (as assessed at MR examinations), and the response to treatment. MATERIALS AND METHODS: Ten daily intravenous injections of gadolinium texaphyrin, each followed by whole-brain radiation therapy (total of 10 fractions, 30 Gy), were administered to patients with brain metastases in a multicenter study. At the study institution, 11 patients underwent MR imaging before and after the first injection, after the 10th injection, and 8 weeks after entry into the study. RESULTS: MR imaging revealed selective drug uptake in metastases, without enhancement of normal brain tissue. In 10 patients, tumor uptake was higher after the 10th injection than after the first injection, which indicated accumulation of gadolinium texaphyrin in metastases. One lesion was visible only after the 10th injection and not at the pretherapeutic MR examination with injection of conventional gadolinium-based contrast material. Response to treatment was defined as a reduction in the size of the metastases between the preinjection MR study and the last MR study; seven patients achieved partial remission with tumor regression exceeding 50% of the initial size, and four achieved a minor response with less than 50% tumor regression. CONCLUSION: These preliminary results indicate that gadolinium texaphyrin is tumor selective and that brain metastases can be depicted at MR imaging long after the administration of gadolinium texaphyrin.     

Assessment of brain metastases with dynamic susceptibility-weighted contrast-enhanced MR imaging: initial results

PURPOSE: To assess if preradiation and early follow-up regional cerebral blood volume (CBV) measurements can help predict treatment outcome in patients with cerebral metastases and to evaluate regional CBV changes in tumor and normal tissue after radiosurgery. MATERIALS AND METHODS: In 18 patients, dynamic susceptibility-weighted contrast material-enhanced magnetic resonance (MR) imaging was performed with a 1.5-T unit, which allowed an absolute quantification of the regional CBV. Measurements were performed prior to and at 6 weeks and 3 months after therapy. Treatment outcome was classified according to tumor volume changes at 6 months. The regional CBV of the metastases and the normal adjacent brain tissue were determined with a region-of-interest analysis. Regional CBV values were correlated with the patient outcome to assess the sensitivity and specificity of dynamic susceptibility-weighted contrast-enhanced MR imaging. RESULTS: The pretherapeutic regional CBV was not able to help predict a treatment outcome; however, the method proved to be highly sensitive and specific for treatment outcome prediction at the 6-week follow-up. A decrease of the regional CBV value helped predict the treatment outcome with a sensitivity of more than 90%. The tumor volume change alone had a sensitivity of only 64%. The measured regional CBV values of normal brain tissue and their ratio were comparable to physiologic data and remained unchanged with therapy. CONCLUSION: The results suggest that dynamic susceptibility-weighted contrast-enhanced MR imaging is a useful method for the assessment of radiosurgically treated brain metastases. The implemented technique with determination of the arterial input function enables an absolute quantification of the regional CBV and prediction of tumor response.     

Three subsequent single doses of gadolinium chelate for brain MR imaging in multiple sclerosis

BACKGROUND AND PURPOSE: A triple-dose (TD) of gadolinium chelate is highly sensitive approach for detecting lesion activity in multiple sclerosis (MS). However, individual TD injections do not provide data on the severity of the pathologic process in a population of lesions, and its clinical use is limited by the cost-benefit considerations. Our aim was to determine whether the use of three subsequent single doses (SD) of a gadolinium chelate in brain MR imaging is useful in detecting MS lesions with different patterns of enhancement. METHODS: In 10 patients, T1-weighted spin-echo images were acquired before and after three intravenous administrations of 0.1 mmol/kg of gadodiamide. RESULTS: In all patients, SD images showed six enhancing lesions; double-dose (DD) images, 13; and TD images, 22. Differences between SD and TD and between DD and TD were significant (P <.018). Six lesions (27%) enhanced with all the three doses; seven (32%), with both DD and TD; and nine (41%), with only TD. Proportions of patients with at least one enhancing lesion were, for SD, four of 10; DD, seven of 10; and TD, nine of 10. In defining active disease in these nine patients, we needed only 19 SDs versus the 30 SDs that would have been needed if individual TD injections were used. CONCLUSION: With three subsequent SD injections, the number of enhancing lesions progressively increases. This approach allows the distinction of three levels of enhancement, and it reduces the amount of contrast agent needed to distinguish patients with active MS from those with nonactive MS.     

Use of gadolinium chelates in MR imaging of the spine

Spinal disease can be divided into intramedullary, extramedullary-intradural, and extradural compartments. In the cord (intramedullary compartment), gadolinium chelates are useful to diagnose primary and metastatic tumors, inflammation, and demyelination, and to evaluate syringomyelia when a Chiari I malformation is not present. In the extra-medulullary-intradural compartment, gadolinium chelates are useful for the diagnosis of drop metastases, meningiomas, and schwannomas. In the extradural compartment, gadolinium chelates are most useful to distinguish recurrent disc herniation from epidural fibrosis in the postoperative back and may be useful to diagnosis the soft tissue component of osseous metastases.     

Galactosemia: evaluation with MR imaging.

The cerebral findings at magnetic resonance imaging in 67 transferase-deficient galactosemic patients (36 female, 31 male; median age, 10 years) are reported. Twenty-two patients had mild cerebral atrophy, eight had cerebellar atrophy, and 11 had multiple small hyperintense lesions in the cerebral white matter on T2-weighted images. The classic galactosemic patients (those without measurable transferase activity) older than 1 year of age did not show the normal dropoff in peripheral white matter signal intensity on intermediate- and T2-weighted images. The authors postulate that this abnormal signal intensity is due to altered myelin formation secondary to the inability to make sufficient and/or normal galactocerebroside.     

Comparison of MR and PET imaging for the evaluation of liver metastases

PURPOSE: To compare the accuracy of fluoro-18-deoxyglucose positron emission tomography (FDG-PET) and dynamic-enhanced magnetic resonance imaging (MRI) scans in the diagnosis of liver metastatic lesions from colon and other sources. MATERIALS AND METHODS: Thirty consecutive patients with known or suspected metastatic lesions were scanned by both MRI and PET. Histopathology and/or clinical outcome, including cross-sectional imaging follow up, were used as a gold standard. RESULTS: Of 30 patients, 16 were positive by pathology and/or clinical outcome and 14 were negative for liver metastases. The sensitivity, specificity, and positive and negative predictive values on MRI were 85.7%, 100%, 100%, and 89%, respectively, compared to 71%, 93.7%, 90.9%, and 79% on FDG-PET. The difference between the two methods was not significant (X(2) = 0.2, P > 0.05). CONCLUSION: Our study showed no significant difference in detection of liver metastases using MRI or FDG-PET. However, MRI has advantages in spatial resolution and lesion characterization.     

Monitoring of irradiated brain metastases using MR perfusion imaging and 1H MR spectroscopy

PURPOSE. In follow-up examinations of irradiated brain metastases conventional contrast-enhanced morphological MR imaging is often unable to distinguish between transient radiation effects, radionecrosis,and tumor recurrence. To evaluate changes of relative cerebral blood flow (rCBF) in irradiated brain metastases arterial spin-labeling techniques (ASL) were applied and compared to the outcome of (1)H MR spectroscopy and spectroscopic imaging ((1)H MRS, SI). PATIENTS AND METHODS. In 2 patients follow-up examinations of irradiated brain metastases were performed on a 1.5-T tomograph (average single dose: 20 Gy/80% isodose). Relative CBF values of gray matter (GM), white matter (WM),and metastases (Met) were measured by means of the ASL techniques ITS-FAIR and Q2TIPS. (1)H MRS was performed with PRESS 1500/135. RESULTS. In both patients with initially hyperperfused metastases (Met/GM >1) the reduction of rCBF after stereotactic radiosurgery indicated response to treatment--even if the contrast-enhancing region increased--while increasing rCBF values indicated tumor progression. The findings were confirmed by (1)H MRS, SI and subsequent follow-up. CONCLUSION. The ASL techniques ITS-FAIR and Q2TIPS are able to monitor changes of rCBF in irradiated brain metastases. The two cases imply a possible role for ASL-MR perfusion imaging and (1)H MR spectroscopy in differentiating radiation effects from tumor progression.     

Multiple sclerosis: gadolinium enhancement in MR imaging

Magnetic resonance (MR) images--both nonenhanced and enhanced with gadolinium DTPA/dimeglumine (Gd)--were compared with high-iodine (88.1 g I) computed tomographic (HICT) scans in demonstrating lesions in 15 patients known to have multiple sclerosis (MS). T1-weighted, mixed (T1, proton density, and T2), and T2-weighted MR pulse sequences were used. More than 20 lesions in each of 14 patients were demonstrated by pre-Gd mixed images and T2WI. Nine patients had clinical symptoms of active disease. Gd-enhanced T1WI showed at least one lesion that appeared to correspond with newly reported symptoms or signs. In addition, three clinically stable patients showed enhancement. Enhancement was best seen on 3-minute T1WI. HICT scans showed enhancement in four of the nine patients with active disease and in none of five clinically stable patients. Gd-enhanced MR imaging appears to be more sensitive than HICT in the detection of the transient abnormalities of the blood-brain barrier that occur in patients with active MS and appears capable of distinguishing active lesions that may correspond to the anatomic regions responsible for abnormal clinical findings.     

Renal transplant evaluation with MR angiography and MR imaging.

Magnetic resonance (MR) angiography is a widely used, noninvasive tool for evaluating the aorta and its branches. It is particularly useful in renal transplant recipients because it provides anatomic detail of the transplant artery without nephrotoxic effects. Volume rendering is underutilized in MR angiography, but this technique affords high-quality three-dimensional MR angiograms, especially in cases of tortuous or complex vascular anatomy. An imaging protocol was developed that includes gadolinium-enhanced MR angiography of the transplant renal artery with volume rendering and multiplanar reformation postprocessing techniques. Axial T2-weighted and contrast material-enhanced T1-weighted MR images are also obtained to examine the renal parenchyma itself and to evaluate for hydronephrosis or peritransplant fluid collections. This imaging protocol allows rapid global assessment of the renal transplant arterial system, renal parenchyma, and peritransplant region. It can also help detect or exclude many of the various causes of renal transplant dysfunction (eg, stenosis or occlusion of a transplant vessel, peritransplant fluid collections, ureteral obstruction). Conventional angiography can thus be avoided in patients with normal findings and reserved for those with MR angiographic evidence of stenosis.     

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。     

MR imaging with histopathological correlation in vertebral metastases of breast cancer.

In 5 patients with advanced breast cancer and spinal metastases MR imaging of the spine was performed before and/or after death. T1-, proton density-, and T2-weighted and "phase contrast" images were obtained in the sagittal plane. Autopsies included histopathologic examination of whole sagittal sections of the vertebral body. The relative signal intensities on the different MR sequences of various tissues identified histologically were evaluated. "Phase contrast" images combined with T1-weighted images were highly sensitive in detecting metastases. All metastatic tumours over 3 mm in size were found with MR imaging. Vertebrae containing connective tissue and reactive bone marrow had an MR appearance similar to that of metastases even though no metastases were found histopathologically.     

MR imaging with gadolinium in patients with and without post-lumbar puncture headache

PURPOSE: To study frequency and extent of meningeal enhancement in patients with and without post-lumbar puncture headache (PLPH) with cerebral MR with Gd-DTPA. MATERIAL AND METHODS: Ten consecutive patients with PLPH and 9 consecutive patients without PLPH were included in the study. Nine of the PLPH patients were reinvestigated when the PLPH was over and all non-PLPH patients during the week after the lumbar puncture. RESULTS: Eight of the 9 patients with PLPH showed more enhancement of meningeal structures during PLPH than when PLPH had disappeared. The differences were slight in 5, more marked in 2, and pronounced in 1 patient. The 9th patient showed no change at all. In the 9 patients without PLPH, there was mainly slight enhancement before lumbar puncture and no change in enhancement after lumbar puncture as compared with before. CONCLUSION: PLPH is related to increased Gd-DTPA enhancement of the meninges, although the increase in enhancement during PLPH is minor in most cases. Pronounced enhancement of the meninges after lumbar puncture may predict long duration of the PLPH.