Germinoma originating in the basal ganglia and thalamus: MR and CT evaluation.

PURPOSETo describe MR and CT features of germinoma originating in the basal ganglia and thalamus and to discuss the roles of each modality for its diagnosis.METHODSMR and CT studies of six cases of germinomas, five of which were histologically proved, were retrospectively reviewed. T1-weighted, T2-weighted, and contrast-enhanced T1-weighted conventional spin-echo images, and unenhanced and contrast-enhanced CT images were evaluated.RESULTSTypically, the tumor consisted of an irregular solid area with contrast enhancement and various-size cysts. Cystic components were found in five cases and calcification in four. Intratumoral hemorrhage was noted in one. Ipsilateral cerebral hemiatrophy and brain stem hemiatrophy were noted in three cases each. MR was superior to CT in evaluating precise tumor extension, cystic components, and intratumoral hemorrhage, although in one case, extension of the tumor was better defined on CT in its early stage. Calcification was difficult to identify by MR alone. The solid components of the tumors generally showed slightly high density on CT, which seemed to be characteristic compared with nonspecific intensity pattern on MR.CONCLUSIONThe combination of CT and MR findings allows early detection and appropriate diagnosis of the mass in the basal ganglia and/or thalamus.     

MRI of porencephalic cyst associated with cerebral hemiatrophy

Whereport seven cases of porencephalic cyst associated with cerebral hemiatrophy. One case was due to an unknown prenatal factor. One case had maternal injury and shock, which presumably caused temporary fetal asphyxia. One case had perinatal asphyxia. The other four cases had infantile head injury; of these, two cases had serial follow-up computed tomography (CT) and magnetic resonance imaging (MRI) that verified the evidence of post-traumatic infarction of the brain, and then caused porencephaly with cerebral hemiatrophy. In the other two cases, MRI clearly showed ulegyria on the side of the lesion, which is evidence of remote hypoxic ischemic damage. These cases lead us to believe that hypoxic ischemic damage of the brain is the etiology of porencephalic cyst when associated with cerebral hemiatrophy or when adjacent ulegyria is present. Correspondence to: W.-C. Shen     

Brain tumors with ipsilateral cerebral hemiatrophy

Brain tumors with secondary ipsilateral cerebral hemiatrophy are so rare that only seven cases have been reported in the literature. Three new cases are presented and the clinical findings in all 10 cases are reviewed. The diagnostic value of computed tomography (CT) is emphasized. The authors conclude that nodular high-density lesions located deep in the cerebrum and showing slight contrast enhancement on CT may be associated with ipsilateral cerebral hemiatrophy in young male patients with slowly progressive hemiparesis, dementia, and personality change. In such cases, early diagnosis of germinoma and subsequent radiotherapy may prevent unnecessary surgery.     

Computed tomography in cerebral hemiatrophy.

The clinical and radiographic findings in four cases of cerebral hemiatrophy are presented. CT findings reflect the underlying gross pathologic changes and are in agreement with those seen on plain skull radiography and pneumoencephalography. The most impressive finding was unilateral loss of cerebral volume with ipsilateral displacement of the midline structures. The differential diagnosis primarily includes Sturge-Weber syndrome and linear sebaceous nevus syndrome. The recognition of compensatory calvarial changes should indicate that the cerebral abnormalities are the result of an atrophic or hypoplastic process that began in early life.     

Percutaneous Radiofrequency Ablation of Hepatocellular Carcinomas Adjacent to the Gallbladder with Internally Cooled Electrodes: Assessment of Safety and Therapeutic Efficacy

Objective

The objective of this study was to evaluate the safety and therapeutic efficacy of percutaneous radiofrequency (RF) ablation for the treatment of hepatocellular carcinomas (HCCs) adjacent to the gallbladder with the use of internally cooled electrodes.

Materials and Methods

We retrospectively assessed 45 patients with 46 HCCs (mean size, 2.2 cm) adjacent to the gallbladder (≤1.0 cm) treated with RF ablation using an internally cooled electrode system. An electrode was inserted into the tumor either parallel (n = 38) or perpendicular (n = 8) to the gallbladder wall. The safety and therapeutic efficacy of the procedures were assessed with clinical and imaging follow-up examinations. Follow-up with the use of CT ranged from four to 45 months (mean, 19 months). The association between variables (electrode direction, electrode type, tumor size, tumor location, lobar location) and the presence of a residual tumor or local tumor progression was also analyzed.

Results

There were no major complications and minor complications were noted in three patients (7%) including one case of vasovagal syncope and two cases of bilomas. Wall thickening of the gallbladder adjacent to the RF ablation zone was noted in 14 patients (41%) as determined on immediate follow-up CT imaging. Wall thickening showed complete disappearance on subsequent follow-up CT imaging. The primary technique effectiveness rate was 96% (44/46) based on one-month follow-up CT imaging. Local tumor progression was noted in six (14%) of 44 completely ablated tumors during the follow-up period. The direction of electrode insertion (perpendicular), tumor size (≥3 cm) and tumor location (a tumor that abutted the gallbladder) were associated with an increased risk of early incomplete treatment. No variable was significantly associated with local tumor progression.

Conclusion

Percutaneous RF ablation of HCCs adjacent to the gallbladder using an internally cooled electrode is a safe and effective treatment. Significant risk factors that lead to early incomplete treatment include tumor size, tumor location and electrode direction.     

Computed tomographic findings in cerebral hemiatrophy

Summary The clinical, plain skull radiographic, brain scan, and CT findings of four patients with cerebral hemiatrophy are described. CT scanning is the most innocuous and most sensitive diagnostic method available to confirm the clinical diagnosis when plain skull radiographic changes are not confirmatory.     

Magnetic resonance imaging of intracranial tumors in children and adolescents

Magnetic resonance (MR) scans were reviewed of 25 children and adolescents from the age of 9 months to 18 years referred with a suspected or proven diagnosis of intracranial tumor. Twenty-one of these children had MR scans positive for tumor. Histology was available in 14. The other seven patients were managed clinically as cases of cerebral tumor, although histologic confirmation was lacking. Seventeen tumors displayed an increase in both T1 and T2. One dermoid tumor and part of another displayed a very short T1 (less than that of white matter). Two hamartomas had T1s similar to that of gray matter and a small increase in T2. Four of the children did not show MR or computed tomographic (CT) evidence of intracranial tumors. Follow-up of these cases for 1-23 months after the MR and CT studies revealed no subsequent clinical evidence of tumor. MR scans showed more extensive abnormality than did third-generation CT scans in eight of 10 cases and more extensive abnormality than EMI CT 1010 scans in 10 of 11 cases. Mass effects were better demonstrated in 14 of the 16 patients in whom they were seen. CT demonstrated calcification better than did MR in all four cases in which it was identified. The tumor-edema interface was shown better on CT in each of the three cases with contrast enhancement on CT. MR is a sensitive method of evaluating intracranial tumors in children and adolescents.     

Oblique approach for CT-guided liver radiofrequency ablation using multiplanar reformation images in hepatocellular carcinoma

Purpose

To evaluate the feasibility and safety of CT-guided radiofrequency (RF) ablation by caudal-cranial oblique insertion using multiplanar reformation (MPR) images for hepatocellular carcinomas (HCCs).

Materials and methods

Twenty-two HCCs in 19 patients that were difficult to demonstrate on ultrasound (mean tumor diameter was 17.5?mm) were treated with CT-guided RF ablation by caudal-cranial oblique insertion to avoid pneumothorax, using MPR images after transcatheter arterial chemoembolization. The insertion point and direction of insertion, avoiding aerated lung parenchyma, bones, large vessels, and intestine, were sought on the MPR images. Technical success was defined as complete eradication of tumor enhancement in the contrast-enhanced CT. Local tumor progression was defined by the appearance of enhanced tumor adjacent to the zone of ablation. The technical success rate, local tumor progression, and complications were investigated.

Results

The coronal plane was used for insertion in 18 tumors, the sagittal plane in 3 tumors, and the oblique plane in 1 tumor. RF electrode placement was successful and complete necrosis was obtained in all cases. During the mean follow-up period of 38.0?months, local tumor progression was not detected in any of the patients. There were no major complications, including pneumothorax.

Conclusion

CT-guided RF ablation by caudal-cranial oblique insertion using MPR images is a feasible and safe therapeutic option.     

Comparaison des tomodensitométrie,cinégammagraphie,et angiographie dans les diagnostics topographique et histologique pré-opératoires de 300 tumeurs intracrâniennes sus-tentorielles

Summary The results of CT, scintigraphy (CSS), and angiography in 300 supratentorial cerebral tumors were compared with regard to the topographic and pathological diagnosis proposed in the initial reports. CT elucidated the topography in 98% of the cases and the pathology in variable percentages, depending on the type of tumor. The use of scintigraphy provided a high accuracy of pathological diagnosis. Except for meningiomas, arteriography was less accurate than the two other methods of examination. A radiological management of supratentorial cerebral tumors is proposed based on clinical and CT data.     

肿瘤非手术治疗后FDG PET随访的临床价值

目的　探讨 FDG PET影像诊断在肿瘤非手术治疗后临床随访中的价值。　方法　选择实质性肿瘤高强度聚焦超声 (HIFU)治疗后 2 1例 ,鼻咽癌患者放射治疗后 14例 ,共 35例 ,随访中同期行 FDG PET和 CT、MRI检查 ,并将结果进行双盲比较。　结果　 2 1例实质性肿瘤 HIFU治疗后 2～ 3个月复查 ,19例 CT、MRI表现密度和信号有变化 ,但形态、大小未见明显改变 ,另 2例 CT、MRI密度和信号变化不明显 ;PET示 17例肿瘤中心大部分放射性分布缺损 ,但以肿瘤边缘部分为主仍有 FDG代谢活跃现像 ,提示部分肿瘤存活 ,其中 6例在 FDG代谢活跃局部经穿刺活检证实肿瘤存活 ;4例 PET表现为 FDG摄取缺损 ,其中 1例局部穿刺活检证实为坏死组织。 14例鼻咽癌放疗后 12～ 18个月复查 ,CT和 MRI提示 11例未见局部肿瘤复发 ,PET显示其中 3例有局灶性 FDG浓聚病变 ,其中 1例局部穿刺活检证实为局部肿瘤复发 ;2例 CT和 MRI提示肿瘤复发 ,FDG显像病变处有明显的放射性浓聚 ;余 1例放射治疗后脑损伤 FDG PET显示为放射性分布缺损区。　结论　 FDG显像在实质性肿瘤 HIFU治疗后疗效判断和鼻咽癌放射治疗后肿瘤复发诊断上较 CT和 MRI准确 ,两者结合分析在临床随访中更具有明显的优势     

Giant cell tumor of the proximal tibia: MR and CT appearance

The magnetic resonance (MR) appearance of four cases of giant cell tumor (GCT) of the proximal tibia are described and the MR grading of these tumors is compared with CT and conventional radiography. Magnetic resonance showed the lesions to be well defined with respect to adjacent marrow and cortical bone. Homogeneous intermediate signal intensity or low signal within the tumors was seen on T1-weighted images. T2-weighted images showed mixed signal intensity with small "bright patches" of increased signal intensity in all four cases. No fluid levels were identified. Magnetic resonance was superior to CT and plain radiography in radiologic grading of the tumors. Computed tomography was superior in determining if cortical invasion was present. Intraarticular tumor extension was more accurately detected by MR and arthrotomography than CT. An MR manifestation of GCT of the proximal tibia is described which may be a common appearance of this tumor by this modality. Magnetic resonance is the procedure of choice in the radiologic grading of GCT.     

CT findings with cerebral hemiatrophy

Summary CT examination of 71 patients with cerebral hemiatrophy revealed dilatation of the ventricle and low density of the cortex of the involved side in all cases. Thickening of the calvarium and a shift of the midline were found in about half of the patients.     

Computed tomography of monkey brain tumors

Thirty-five Japanese monkeys were inoculated intracerebrally with chick embryo fibroblasts that were producing Schmidt-Ruppin strain of Rous sarcoma virus. Tumors were induced in 54.3% (19/35). Computed tomography detected tumors in 10 symptomatic animals with an average latency of 32.6 (15-43) days. At autopsy, the brains were sectioned into 5 mm slices, coplanar to the CT image. Various CT features of high- and low-density area correlated well with the histopathological findings, such as tumor, hemorrhage, necrosis, and peritumoral edema. Contrast-enhanced CT detected 10 tumors greater than 4 mm in diameter, and there was +/- 2 mm potential error in determining tumor size. Follow-up CT revealed growth of tumors in four animals and stabilization of tumor in two animals. Large brain size, 90-110 g in adult monkeys, and availability of induced tumors offer an excellent brain tumor model for CT studies.     

Therapeutically infarcted tumors: ct findings

The CT findings in 14 patients who underwent hepatic or renal embolizations are presented. In 11 patients who had postinfarction CT studies, linear, branching air collections were noted within the embolized tumor. In two patients the amount of air increased on later CT studies. This configuration of air suggested an abscess, but in no case was an abscess encountered. This air was located distal to the high density embolization material in four cases. In four cases the infarcted organ appeared denser due to "trapped contrast." The seven embolized livers did not change in size on follow-up examinations, while three renal tumors demonstrated variable size changes after embolization.     

Computed tomography in spastic cerebral palsy

Summary Eighty-three children with spastic cerebral palsy (CP) were examined with cranial CT. In 56 cases the CT findings were abnormal. The most frequent abnormality was atrophy, present in 44 patients. The frequency of pathologic CT increased with severity of the CP. Patients with CP of postnatal aetiology more often had abnormal CT than patients with other known causes. Pathologic CT findings were seen more often in patients with seizures than in patients without. Infarctions and hemiatrophy were much more frequent in patients with hemiplegia than in patients with other types of spastic CP. A special kind of central atrophy, called isolated atrophy around the cella media, is described. This condition was seen in 20% of cases, most often in hemi- and paraplegic patients. Early infarctions in the border areas between the vascular territories of the internal carotid and the posterior cerebral artery may be the reason for this kind of atrophy.     

多层螺旋CT对胃肠道外间质瘤的诊断价值

目的 探讨胃肠道外间质瘤(EGIST)的CT表现及其诊断价值. 方法 回顾性分析经手术病理证实的19例EGIST的CT资料.结果 肿瘤位于腹膜后8例、肠系膜4例,腹腔4例,原发于肾上腺1例、大网膜1例,网膜及肠系膜1例.良性2例,交界性4例,恶性13例.肿瘤直径4.1～35 cm,类圆形5例,分叶状5例,不规则形9例.平扫密度均匀4例, 增强扫描1例均匀中度强化,1例不均匀强化,2例周边明显环形强化;平扫密度不均匀15例,增强扫描实质部分中度以上强化,囊变坏死部分强化不明显. 结论 EGIST的CT表现具有一定特点, MSCT对EGIST的诊断及鉴别诊断有重要价值.     

子宫阔韧带肌瘤的CT诊断

目的　探讨子宫阔韧带肌瘤的CT诊断价值。方法　收集 2 1例子宫阔韧带肌瘤CT资料 ,进行回顾性分析 ,所有病例均经手术病理证实。结果　 2 1例均在盆腔内、子宫外显示肿块 ,CT表现 :实质性肿块 19例 ,边界清楚光整 16例 ,不甚清楚 3例 ,密度均匀 6例 ,平扫时与子宫肌密度相当 ,增强扫描呈明显强化 ,与子宫肌强化基本同步 ,不均匀 13例 ,其强化程度低于子宫肌 (约相差 10～ 2 0HU) ,瘤内变性、坏死或液化区不明显强化或不强化 ;囊实性 2例 ;肿块位置较固定 ,大多在宫旁匍匐生长 ,与子宫位置密切相关 ,其最大径层面与子宫体中心层面基本保持一致 ;形态各异 ,呈条块状、哑铃分叶状及扁圆烧饼状共 15例 ,呈圆形、椭圆形6例。结论　子宫旁呈条块、哑铃分叶状及扁圆烧饼状的实质性或实质性为主的肿块是本病较为可靠的CT征象 ,CT对诊断阔韧带肌瘤有实用价值     

小儿腹膜后成神经细胞瘤影像学与病理的对照研究

目的 探讨ＣＴ、ＭＲＩ对小儿腹膜后成神经细胞瘤的诊断价值和限度。方法 对３２例中２０例术前同时行ＭＲＩ、ＣＴ检查者与术中所见对照,并对其中１９例术后离体肿瘤的ＭＲＩ、ＣＴ影像与病理大切片对照。结果 ＭＲＩ表现一般为Ｔ１Ｗ１中低信号,Ｔ２Ｗ１明显高信号,且可见低信号网格及肿瘤对血管的包绕。组织学基础：原始成神经细胞核大密集,无间质;瘤巢周围有神经纤维。ＣＴ表现肿瘤为不均匀低密度,可见钙化。术前判断肿     

Primary mediastinal endodermal sinus tumors: CT evaluation

Five patients with primary mediastinal endodermal sinus tumor have been evaluated by computed tomography (CT). The tumors were all located in the anterior mediastinum. Prechemotherapy CT demonstrated large, irregularly enhancing inhomogeneous masses without fat components. Calcification was visualized in two tumors. Some parts of the pleura-lung interface were irregular in four cases. Obliteration of fat planes to pericardium and chest wall was evident in all cases, and there was infiltration of intercostal muscles in four. Postchemotherapy CT in two patients who responded to chemotherapy showed either newly developed cystic lesions or cystic change of the original mediastinal mass. The cystic masses had more regular borders, a homogeneous hypodense center, and a smooth peripheral rim of contrast-enhancing tissue.     

CT and MRI aspects of 28 patients with cerebral radiation necrosis irradiated for ORL tumors: correlation with the radiation technique

PURPOSE: To describe and correlate with radiation therapy the occurrence of cerebral radiation necrosis in patients irradiated for nasopharyngeal or ethmoidal tumor. Materials and Methods. From 1986 to 1998, 1 201 patients, 981 with nasopharyngeal tumors, and 220 with ethmoidal tumors were treated by radiotherapy. Twenty eight developed cerebral necrosis. MRI were performed in all patients and CT in 18 patients. Diagnosis was considered at imaging, and confirmed by follow-up. RESULTS: The incidence of cerebral radionecrosis was 2.33%. The time interval between treatment and necrosis ranged from 2 months to 9 years. CT showed edema and/or focal enhancement in all cases except for 4 patients with normal CT examinations. MRI showed edema and/or abnormal focal punctate or gyriform enhancement in all patients. Lesions were localized in the temporal lobe (n=18), frontal lobe (n=9), pons (n=3) and optic nerve (n=2). The doses related to the areas of necrosis ranged from 13 to 135Gy. In 2 cases necrosis was situated at the boundaries of the radiation field. Imaging follow-up showed complete (n=3) or incomplete remission (n=1), lesion progression (n=11), cerebral atrophy (n=5) and stability (n=7). CONCLUSION: MRI is useful to diagnose cerebral necrosis. New technologies may reduce the incidence of this complication.