CT-analyses of cerebral tumors under steroid therapy

Summary In order to determine, by CT density and volume measurements, the influence of steroid therapy on cerebral tumors, on their perifocal edema and on the uninvolved cerebral tissue, CT follow-up studies of 37 patients were analysed. In general a decrease of tumor density is to be seen within the first 10 days of therapy. Under continuous steroid application absorption coefficients then increase again, so that no cortisone effect on the tumor remains. The tumor size does not alter: in particular at no time is growth retardation detectable under cortisone therapy. Intensity and extension of the perifocal edema decrease in two stages. From this delayed course we conclude the cytotoxic component of the tumor edema to be more extensive than supposed. Deviations appear dependent on tumor histology, which should lead to individualied steroid application.     

脑膜瘤伴瘤周水肿的MRI特征分析

目的:探讨脑膜瘤伴瘤周水肿的机制。方法:49例经手术病理证实的脑膜瘤,回顾性分析伴有瘤周水肿脑膜瘤的MRI特征,用Fisher′s检验比较肿瘤大小、部位、边缘、假包膜征及肿瘤T2WI信号与瘤周水肿发生的关系。结果:肿瘤边缘、假包膜征和肿瘤T2WI信号与脑膜瘤瘤周水肿发生明显相关,P值分别是0.016,0.004 和0.041。结论:脑膜瘤脑界面侵袭性模式和T2WI高信号是提示脑膜瘤发生瘤周水肿的因素。     

灶周水肿对脑瘤卒中与单纯脑出血的CT鉴别诊断辅助价

目的：探讨灶周水肿对脑瘤卒中与单纯脑出血的ＣＴ鉴别诊断的辅助价值。材料与方法：１０例中,男７例,女３例。年龄１７～６６岁,均急性起病。发病至初次ＣＴ检查时间２～２４小时。５例还作了ＣＴ增强检查。结果：星形细胞瘤７例,脑膜瘤３例。ＣＴ表现：１０例均见境界清楚的高密度血肿;５例见肿瘤实体,５例未见明显瘤灶;Ⅲ级灶周水肿６例,Ⅰ、Ⅱ级灶周水肿各２例,均与血肿期龄不符。结论：脑瘤卒中早期,灶周水肿主要由肿瘤引起的血管源性水肿,而非血肿产生。所以在瘤体不明显的病例,如发现灶周水肿与血肿期龄不符,应考虑肿瘤卒中可能     

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.     

Large-sized brain metastasis of lung cancer without perifocal edema: case report

A very rare case of a large-sized brain metastasis of lung cancer without perifocal edema is reported. This case suggested that the degree of perifocal edema may depend on the localization of the tumor.     

Application of contrast agents in CT and MRI (NMR): their potential in imaging of brain tumors

Summary 21 patients with clinical and CT diagnoses of intracranial tumor were studied by MRI (NMR) prior to and after administration of intravenous Gadolinium-DTPA. Resultant MRI images were compared with corresponding CT sections with respect to lesion detection, contrast enhancement, tumor delineation and visualization of perifocal edema. All intracranial lesions shown on CT were identified on MRI. Contrast enhancement in MRI images was achieved in 19 out of 21 patients, as it was also with CT. In these cases improved differentiation between tumor, perifocal edema and adjacent brain structures were obtained. In most cases sufficient visualization of perifocal edema in MRI required T₂ weighted images (SE 1600/70) in addition to spin echo scans routinely performed prior to and after contrast medium (SE 400/30 or 800/30). No side effects were encountered following administration of Gadolinium-DTPA. The good tolerance and the efficacy justifies the use of Gadolinium-DTPA for contrast enhanced MRI imaging.Dedicated to Professor S. Wende on the occasion of his 60th birthday     

Patterns of Failure Following CT-Based 3-D Irradiation for Malignant Glioma

BACKGROUND: This retrospective study was undertaken to analyze the patterns of failure in patients with malignant glioma after localized irradiation. PATIENTS AND MATERIALS: Recurrence patterns of 46 patients with malignant glioma (glioblastoma: 24, anaplastic astrocytoma: 15, anaplastic oligodendroglioma: 5, unclassified malignant glioma: 2) were studied using CT/MR scans and radiotherapy plan-plots. All patients were operated before and a total dose of 5,940 cGy was given after CT assisted and individually configurated 3-D planning using 7-15 slices at an in between distance of 5 mm. The target volume included a 2-3 cm margin beyond the tumor indicated by preoperative CT scan. The following parameters were analyzed: tumor size and type, size of perifocal edema and whether the edema was fully included into treatment volume and finally the location of the recurrent tumor. The maximal distance between primary tumor and recurrent tumor was measured and also the distance from the border of the primary tumor to the distant border of edema for a visual analysis. RESULTS: Local limited volume irradiation was sufficient since 73.9% of recurrences occurred within 2 cm distance from primary tumor and 93.5% of recurrences occurred completely within 3 cm distance from primary tumor. Regarding the distance between primary tumor and recurrent tumor and the time interval until appearance of recurrent tumor it was not of importance if perifocal edema was included completely into treatment volume or not. CONCLUSION: Limited volume irradiation of malignant glioma with a target volume 3 cm beyond that indicated by preoperative CT scan seems to be sufficient, since 93.5% of recurrences were completely within 3 cm distance from the margin of the tumor. Improvement of the results with larger treatment volumes are unlikely. Complete irradiation of perifocal edema was not found to be necessary.     

Incorporating functional MR imaging into diffusion tensor tractography in the preoperative assessment of the corticospinal tract in patients with brain tumors

BACKGROUND AND PURPOSE: Our goal was to improve the preoperative assessment of the corticospinal tract (CST) in patients with brain tumors. We investigated whether the integration of functional MR imaging (fMRI) data and diffusion tensor (DT) tractography can be used to evaluate the spatial relationship between the hand and foot fibers of the CST and tumor borders. MATERIALS AND METHODS: We imaged 10 subjects: 1 healthy volunteer and 9 patients. Imaging consisted of a 3D T1-weighted sequence, a gradient-echo echo-planar imaging (EPI) sequence for fMRI, and a diffusion-weighted EPI sequence for DT tractography. DT tractography was initiated from a seed region of interest in the white matter area subjacent to the maximal fMRI activity in the precentral cortex. The target region of interest was placed in the cerebral peduncle. RESULTS: In the healthy volunteer, we successfully tracked hand, foot, and lip fibers bilaterally by using fMRI-based DT tractography. In all patients, we could track the hand fibers of the CST bilaterally. In 4 patients who also performed foot tapping, we could clearly distinguish hand and foot fibers. We were able to depict the displacement of hand and foot fibers by tumor and the course of fibers through areas of altered signal intensity. CONCLUSION: Incorporating fMRI into DT tractography in the preoperative assessment of patients with brain tumors may provide additional information on the course of important white matter tracts and their relationship to the tumor. Only this approach allows a distinction between the CST components, while visualization of the CST is improved when fiber tracking is hampered by tumor (infiltration) or perifocal edema.     

Multiple sclerosis simulating brain tumor on computed tomography

A 44-year-old woman with multiple sclerosis (MS) stimulating a brain tumor on CT is reported. At the first hospitalization, a heterogeneously enhancing mass lesion with perifocal edema was identified on CT in the left parietal lobe. Biopsy of the lesion revealed necrotic change of the brain, gliosis, and perivascular cuffing; several months later no tumor cells were identified. The follow-up CT revealed reduction of the enhancing lesion and disappearance of the perifocal edema, with only a low density area persisting. At the second hospitalization, CT revealed a ring enhancing lesion with perifocal edema in the right temporoparietal region. Follow-up CT several months later revealed reduction of the lesion, with the residual of a small low density area. Magnetic resonance (MR) allowed us to identify multiple lesions in addition to those visualized on CT. In some cases of MS, the CT findings are very similar to those found in brain tumors. In these instances, MR is more useful in the diagnosis of MS than CT.     

Meningiomas with brain edema: radiological characteristics on MRI and review of the literature

OBJECT: Despite their benign characteristics, meningiomas are often accompanied by perifocal brain edema. The aims of this study are to determine what kind of characteristics on magnetic resonance (MR) image are indicative of a meningioma that produces brain edema and to investigate the mechanism responsible for brain edema accompanying meningiomas. METHODS: Fifty-one patients with meningioma were examined by magnetic resonance imaging (MRI), and tumor size, tumor location, shape of tumor margin, peritumoral rim, and signal intensity of tumor on T2-weighted image (T2WI) were compared and correlated with the presence versus absence of brain edema. Surgical histopathology was also examined and correlated with the MRI findings and brain edema. RESULTS: Shape of tumor margin, peritumoral rim, and signal intensity of tumor on T2WI correlated with brain edema on multivariate analyses. CONCLUSION: Invasive pattern of brain-tumor interface and hyperintensity on T2WI were indicative factors of meningiomas producing brain edema.     

Time-dependent changes in image contrast in brain tumors after gadolinium-DTPA

Time-dependent changes in the contrast enhancement of tumor tissue, tumor necrosis, perifocal edema, and normal brain tissue after IV injection of 0.1 mmol gadolinium-DTPA/kg body weight were studied with spin-echo technique (SE 800/35) in 15 patients with intracranial tumors. Using a region of interest technique, we determined the signal-intensity values of these tissues before and at fixed times up to 68.5 min after administration of the contrast agent. In tumor tissue, the 8.5 min postinjection (p.i.) scan showed a significant increase in signal intensity. The signal intensity of the tumor tissue remained significantly higher than precontrast levels throughout the entire period of observation, decreasing only slightly toward the end of the examination (48.5 and 68.5 min p.i.). Central tumor necrosis exhibited a delayed uptake of the contrast agent, with a maximum signal intensity between 48.5 and 68.5 min p.i. In perifocal edema and normal brain tissue, slight increases in signal intensity after injection of gadolinium-DTPA were measured (statistically significant in the case of edema). This effect, however, was not visually detectable. The present study shows that after one injection, scans with excellent tumor visualization can be obtained between 8.5 and 38.5 min p.i. and with diagnostically valid enhancement at least up to 68.5 min p.i.     

脑型血吸虫病的扩散加权成像表现

目的：探讨脑型血吸虫病的扩散加权成像表现。方法：8例脑型血吸虫病患者,在常规MRI检查基础上行DWI扫描。分析DWI图像,测量血吸虫病灶、灶周水肿及对侧正常脑组织的ADC和eADC值。结果：DWI图上,血吸虫病灶和灶周水肿均呈等信号或稍高信号。脑血吸虫病灶、灶周水肿和对侧正常脑组织的ADC值分别为（14.78±0.98）×10^-4mm^2/s、（15.41±1.87）×10^-4mm^2/s和（8.48±0.92）×10^-4mm^2/s,eADC值分别为0.23±0.02、0.20±0.04和0.43±0.04。结论：磁共振DWI和ADC、eADC值测量可为脑型血吸虫病的诊断提供有价值的信息。     

MRI联合4D CEMRA诊断四肢远端长骨转移瘤

目的：探讨 MRI联合4D CEMRA诊断四肢远端长骨转移瘤的意义。方法：分析经手术病理证实的6例四肢远端长骨转移瘤患者的 MRI、4D CEMRA资料,评估每例长骨转移瘤病变部位、骨质破坏类型、病变周围水肿、病变信号特点;测量4D CEMRA长骨转移瘤各期相信号强度,计算各期相瘤体信号与动脉信号的比值,比较不同期相瘤体的信号差异。结果：①骨质破坏部位类型：皮质型2例,均位于骨干。髓腔型4例,3例位于骨端,1例位于骨干。②病变水肿程度：6例中病变周围大片明显水肿5例,小片状轻度水肿1例。③病变信号：6例病例 MRI 平扫均表现信号不均匀,增强扫描6例病例肿瘤实质部分明显强化,T1 WI呈更低信号影未见强化。④4D CEMRA表现：动脉期6例瘤体迅速显影、瘤体信号明显增强,瘤体显现范围明显增大,4例呈“挂果征”改变,1例呈“抱球征”改变;至平衡期,瘤体显影范围固定,显影较静脉期稍减弱。6例长骨转移瘤显示瘤体供血动脉。瘤体供血动脉≤3支有2例;＞3支有4例。4D CEMRA 上瘤体供血动脉呈网状（Ⅰ）、粗短状（Ⅱ）、长条状（Ⅲ）3种表现。结论：长骨转移瘤 MRI表现多样性,结合4D CEMRA的恶性新生肿瘤血管和瘤体染色特点有助于提高诊断准确率。     

The value of fractionated afterloading therapy in the treatment of inoperable malignant brain tumor

Since 1985, inoperable brain tumors, astrocytoma III or glioblastoma multiforme, have been treated by means of fractionated afterloading therapy combines with subsequent percutaneous irradiation. A screw that was specifically designed, allowed us to fix a precious metal tube to the skull cap for about eight days making possible the application of a marginal tumor dose of 30 Gy at a daily fractionation of 2 X 2 Gy using the iridium-afterloading-technique. Percutaneous saturation with another 30-40 Gy followed. Supported by radiobiological considerations, fractionation also appears to have a favorable influence on the perifocal edema formation in the brachytherapy of malignant brain tumors. After an observation period of four years probabilities of survival amounting to six months and twelve months can be calculated (according to Kaplan-Meier) for 68% and 27% of the total collective, respectively (n = 38). The survival rate for patients without pretreatment (n = 16) was 81% and 41% after six and twelve months respectively.     

Patterns of Failure Following CT-Based 3-D Irradiation for Malignant Glioma

Background: This retrospective study was undertaken to analyze the patterns of failure in patients with malignant glioma after localized irradiation. Patients and Materials: Recurrence patterns of 46 patients with malignant glioma (glioblastoma: 24, anaplastic astrocytoma: 15, anaplastic oligodendroglioma: 5, unclassified malignant glioma: 2) were studied using CT/MR scans and radiotherapy planplots. All patients were operated before and a total dose of 5,940 cGy was given after CT assisted and individually configurated 3-D planning using 7-15 slices at an in between distance of 5 mm. The target volume included a 2-3 cm margin beyond the tumor indicated by preoperative CT scan. The following parameters were analyzed: tumor size and type, size of perifocal edema and whether the edema was fully included into treatment volume and finally the location of the recurrent tumor. The maximal distance between primary tumor and recurrent tumor was measured and also the distance from the border of the primary tumor to the distant border of edema for a visual analysis. Results: Local limited volume irradiation was sufficient since 73.9% of recurrences occurred within 2 cm distance from primary tumor and 93.5% of recurrences occurred completely within 3 cm distance from primary tumor. Regarding the distance between primary tumor and recurrent tumor and the time interval until appearance of recurrent tumor it was not of importance if perifocal edema was included completely into treatment volume or not. Conclusion: Limited volume irradiation of malignant glioma with a target volume 3 cm beyond that indicated by preoperative CT scan seems to be sufficient, since 93.5% of recurrences were completely within 3 cm distance from the margin of the tumor. Improvement of the results with larger treatment volumes are unlikely. Complete irradiation of perifocal edema was not found to be necessary. Hintergrund: Diese retrospektive Auswertung wurde unternommen, um das Muster von Lokalrezidiven nach einer lokalisierten Strahlentherapie bei malignen Gliomen zu untersuchen. Patienten and Methode: Rezidivmuster von 46 Patienten mit malignen Gliomen (Glioblastom: 24, anaplastisches Astrozytom: 15, anaplastisches Oligodendrogliom: 5, unklassifiziertes malignes Gliom: 2) wurden anhand der CT-MR-Bilder, Bestrahlungspläne und Isodosen analysiert. Alle Patienten wurden vorher operiert und erhielten eine Dosis von 59,4 Gy. Die Bestrahlungsplanung erfolgte als 3-D-Plan and 7-15 CT-Ebenen bei Schichtabständen von 5mm. Das Zielvolumen beinhaltete 2-3 cm Umgebung des Tumorvolumens im präoperativen CT mit Kontrastmittel. Folgende Parameter wurden analysiert: Tumorgröße und Histologie, Größe des perifokalen Ödems und ob das perifokale Ödem komplett mitbestrahlt wurde, und schließlich die Lokalisation des Rezidivtumors. Ergebnisse: 73,9% der Lokalrezidive lagen innerhalb von 2 cm Abstand um den Tumor und 93,5% innerhalb von 3 cm Abstand. Bezüglich der Entfernung zwischen dem Primärtumor und dem Rezidiv war es ohne Bedeutung, ob das perifokale Ödem groß war bzw. ob das Ödem komplett im Zielvolumen lag. Schlussfolgerung: Kleinvolumige Bestrahlung mit einem Sicherheitsabstand von 3 cm um den Tumor erscheint ausreichend, da 93,5% der Rezidive vollständig in diesem Volumen liegen. Eine Verbesserung der Ergebnisse durch die Vergrößerung der Zielvolumina ist daher eher unwahrscheinlich. Es hatte in unserem Kollektiv keinen Einfluss auf das Rezidivmuster, ob das perifokale Ödem komplett in das Bestrahlungsvolumen einbezogen wurde oder nicht.     

粟粒性脑结核的MRI诊断

目的：观察粟粒性脑结核的MRI征象,探讨MRI各序列对本病的诊断价值。方法：回顾性分析13例临床确诊并经抗结核治疗痊愈或有效的粟粒性脑结核患者的MRI和相关临床资料。全部病例均行MRI平扫及增强扫描,1例行DWI检查。结果：粟粒性脑结核多发生于大脑半球灰白质交界区,直径≤3mm。大部分结节T1WI呈等或稍低信号,T2WI及T2FLAIR呈稍高信号或中心＂靶征＂,伴不同程度灶周水肿,增强后呈小结节样或环形强化。部分早期未成熟结节平扫各序列均呈等信号,DWI亦无异常发现,无灶周水肿,仅增强扫描呈小结节样强化。结论：粟粒性脑结核的MRI表现具有一定特征,增强扫描可发现更多病灶,是必不可少的检查手段。     

MR imaging of the liver before and after transcatheter hepatic chemo-embolization for hepatocellular carcinoma

Transcatheter chemo-embolization (TCE) in hepatocellular carcinoma (HCC) was performed in 38 patients. The patients were examined by MR imaging before TCE as well as one week and 4 to 5 weeks after TCE. The tumor signal intensity in T2 weighted images increased in 13 cases and decreased in 19 cases after TCE. Increased intensity seemed to reflect intra-tumoral hemorrhage or liquefaction accompanying tumor necrosis. Decreased intensity seemed to reflect coagulation necrosis. In 9 of 18 cases followed over a 2-month period the signal intensity had decreased in both T1 and T2 weighted images. In these patients the tumor showed no recurrence at angiography and the decreased signal seemed to reflect the completion of coagulation necrosis. A hyper- and/or hypointense rim around the tumor appeared in 22 cases. These changes were thought to be perifocal edema or granulation tissue around the tumor. MR imaging was useful in evaluating the necrotic process of the tumor after TCE.     

Monitoring of liver metastases after stereotactic radiotherapy using low-MI contrast-enhanced ultrasound—initial results

The purpose of this study was to monitor liver metastases after radiotherapy using contrast-enhanced ultrasound (CEUS). In 15 patients, follow-up examinations after stereotactic, single-dose radiotherapy were performed using CEUS (low mechanical index (MI), 2.4-ml SonoVue) and computed tomography (CT). Besides tumor size, the enhancement of the liver and the metastases was assessed at the arterial, portal venous, and delayed phases. The sizes of the tumor and of a perifocal liver reaction after radiotherapy measured with CEUS significantly correlated with those measured at CT (r=0.93, p<0.001). CEUS found a significant reduction of the arterial vascularization in treated tumors (p<0.05). In the arterial phase, the perifocal liver tissue was hypervascularized compared to the treated tumor (p<0.001); in the late phase, it was less enhanced than the liver (p<0.001) and more than the tumor (p<0.01). The perifocal liver reaction was also seen in CT, but with a variable enhancement at the arterial (50% hyperdense compared to normal liver tissue), venous, or delayed phase (each with 70% hyperdense reactions). CEUS allows for the assessment of tumor and liver perfusion, in addition to morphological tumor examination, which was comparable with CT. Thus, changes of tumor perfusion, which may indicate tumor response, as well as the perifocal liver reaction after radiotherapy, which must be differentiated from perifocal tumor growth, can be sensitively visualized using CEUS.     

Spontaneous osteonecrosis of the medial compartment of the knee: a MRI follow-up after conservative and operative treatment, preliminary results

Symptoms in patients suffering from spontaneous osteonecrosis of the knee (SONK) may be reduced by high tibial osteotomy (HTO). However, the fate of the necrotic lesion is unknown and needs further investigation. We conducted a prospective study to evaluate magnetic resonance imaging (MRI) changes after operative and nonoperative treatment. Ten consecutive patients suffering from SONK of the medial compartment were given two treatment options: either HTO (n = 6) or conservative treatment with partial weight bearing for 3 months (n = 4). We measured the greatest extent of well-defined subchondral low signal intensity abnormality, considered to represent necrosis, and the surrounding area of intermediate signal intensity, considered to represent perifocal bone marrow edema, on T1-weighted coronal MRI images before and after treatment. The MRI follow-up period was 17.5 months (range 12–¶27) in the HTO group and 14.5 months (range 8–25) in the nonoperative group. At follow-up the MRI evaluation revealed a decrease in the low signal intense areas (necrosis) in five of the six patients in the HTO group. Only one of the four nonoperative patients showed a decrease in the low signal intense area. The intermediate intense areas (edema) decreased in all patients in the HTO group and in three of four in the nonoperative group. The mean decrease in the area of perifocal edema was significantly greater in the HTO group than in the nonoperative group (P = 0.019). No statistically significant difference was found for the area of necrosis between the two groups (P = 0.171). A clinical improvement was observed in all patients of the HTO group but in only two of the four patients of the nonoperative group. We conclude that the decrease in perifocal bone marrow edema seems to be associated with improved patient comfort. The MRI appearance of the necrotic lesion does not alter with either treatment mode.     

MR imaging and single-photon emission CT findings after gene therapy for human glioblastoma

BACKGROUND AND PURPOSE: Our goal was to evaluate MR imaging findings after local intracerebral gene therapy in patients with glioblastoma and differentiate postoperative contrast enhancement phenomena. METHODS: In all, 26 patients with supratentorial single lesion glioblastoma underwent tumor resection and intracerebral injection of murine retroviral vector-producer cells for gene therapy with the herpes simplex virus type I thymidine kinase gene/ganciclovir system. Serial contrast-enhanced MR studies were obtained before treatment and postoperatively on day 1 or 2; weeks 2, 4, 9, 13, 17, 25, and 33; and every 8 weeks thereafter. Iodomethyltyrosine single-photon emission CT (IMT-SPECT) investigations also were performed in selected cases. RESULTS: Twelve patients showed nontumorous enhancement of various intensities after treatment, arising within 18 to 72 hours and persisting at 3 to 10 months. It was characterized by a strong local enhancement up to 20 mm thick, which was initially nodular and later linear along the resection cavity wall and surrounded by massive perifocal edema. This "flare" enhancement had features that clearly differed from those of residual tumor enhancements and benign postsurgical enhancements. The IMT-SPECT investigations showed increased amino acid uptake in patients with enhancement from residual or relapsing tumor, but not in patients with flare. CONCLUSION: After local gene therapy, a unique dynamic, transient perifocal flare enhancement can occur on MR images. IMT-SPECT may help to differentiate between tumorous and nontumorous flare enhancements in patients with enhancing tissue on MR images after gene therapy for glioblastoma.