Brain stem tumors

The most common brain stem tumor in both the adult and pediatric population is the brain stem glioma. MR has significant advantages over CT in detecting the presence of the tumor as well as evaluating its extent. Diagnosis must be as precise as possible, since therapy is generally administered without biopsy material available for pathologic examination. Defining the extent of the tumor is mandatory so that appropriate radiation therapy margins are available and geometric misses do not occur. Unenhanced CT may yield some prognostic information regarding patients who have brain stem gliomas. Further work must be done to determine if any MR correlates, such as calculated T1- or T2-relaxation times, can provide similar information. Also, work relating to any prognostic information provided by the appearance of gadolinium enhancement should be undertaken. With MR, the ability to differentiate brain stem glioma from other posterior fossa tumors and from benign lesions that often do not require therapy now exists.     

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.     

Brain tumors: MR imaging with gadolinium-DTPA

Magnetic resonance (MR) imaging was performed on 40 patients with intracranial tumors, before and after intravenous administration of gadolinium-DTPA (Gd-DTPA). Precontrast studies included a comprehensive protocol of spin-echo sequences. Tumors were visualized on precontrast images either directly or indirectly by anatomic distortion caused by the mass. However, differentiation of the tumor from adjacent tissues was possible in only 17 of 40 cases. Delineation of the tumor was best on precontrast, T2-weighted images. After administration of Gd-DTPA (0.1 mmol/kg), increased signal intensity from the tumor was observed in all patients. The localized increase in signal intensity in the tumor considerably improved the tumor delineation in 36 of 40 patients. Whereas most of the meningiomas, neuromas, and adenomas could be delineated prior to administration of contrast material if appropriate pulse sequences were applied, glioblastomas and intracranial metastases required Gd-DTPA administration for diagnostically sufficient tumor display.     

Brain stem auditory evoked potentials in various tumors in the cerebellopontine angle

Abnormalities of brainstem auditory evoked potentials of 63 patients with tumours in the pontocerebellar angle were classified in 7 types and correlated by size and nature of tumours. Types A and B brainstem responses are characteristic for small tumours up 20 mm and are indicated for computed pneumocysternography in spite of the negative CT of the brain. Type C is statistically more frequently found than larger tumours over 22 mm in size. Other types of responses which are more characteristic for tumours which are not neurinomas are described. Auditory evoked potentials are the most reliable neuro-otologic methods in detection of PCU tumours and their careful analysis provides valuable data both about the size and nature of tumours.     

Brain tumors: complications of cerebral angiography accompanied by intraarterial chemotherapy.

PURPOSE: To evaluate the rate of complications associated with diagnostic cerebral angiography accompanied by intraarterial chemotherapy for the treatment of primary and metastatic brain tumors. MATERIALS AND METHODS: Three hundred ninety-two consecutive transfemoral cerebral angiographic procedures accompanied by intraarterial chemotherapy were performed in 48 patients (28 men, 20 women), and complications were evaluated. RESULTS: The most common local complications were groin hematomas, which occurred in 10 (2.6%) of the 392 procedures and none of which required therapy. Two carotid arterial dissections (0.5%) were reported in two patients who were asymptomatic and did not require further treatment. Both improved at follow-up examinations. Only one patient required surgery for a delayed popliteal embolus. Systemic transient complications occurred five times (1.3%). There were seven (1.8%) transient neurologic events, which were paresis and visual disturbances. Six (1.5%) transient seizure events were recorded. There were no permanent neurologic complications. CONCLUSION: Intraarterial chemotherapy for brain tumors is a safe procedure with a low complication rate.     

Brain scintigraphy (SPECT) with thallium-201 in primary brain tumors]

We evaluated the role of thallium-201 single-photon emission-computed tomography (SPECT) in diagnosis, differential diagnosis and follow-up of 33 patients with primary brain tumors. 27 of 33 lesions were detectable by Tl-201 SPECT because only two of eight low-grade (grade 1 and 2) astrocytomas showed Tl-201 accumulation up to a tumor to nontumor ratio of 2.6. High grade (grade 3 and 4) astrocytomas showed Tl-201 accumulation in the range of 2.2 up to 13.0 and were different from low-grade astrocytomas. Noninvasive grading of astrocytomas is therefore possible, whereas differential diagnosis of oligodendrogliomas and astrocytomas or meningiomas was not possible with Tl-201. In the follow-up of six patients, we could demonstrate, that tumor progression is correlated with increasing and tumor regression with decreasing Tl-201 accumulations. This functional changing proceed morphological findings in CT. But vanishing of Tl-201 accumulation during therapy does not mean vanishing of tumor as could be demonstrated by follow-up.     

脑转移癌近距离放射治疗配合外照射治疗的临床分析

目的 探讨立体定向近距离放射治疗配合外照射治疗脑转移癌的方法及疗效。方法 自1994年4月～1999年4月，采用立体定向后装近距离放射治疗配合外照射治疗脑转移癌19例(均为肺癌恼转移，孤立或两个病灶)。近距离治疗剂量为25～35Gy／10～12次／7～10d。全脑外放疗剂量为30～40Gy／3～4周。结果 总缓解率为84．2％(16／19)。一年局部控制率为60．0％(6／10)。中位生存11个月。随诊期内未出现严重并发症。结论 近距离放射治疗配合外放疗能够改善脑转移癌病人的生存质量及生存期。不会增加严重放射性并发症的发生率。     

Brain stem tumors in children (a review of 26 cases 1960--1976).

We reviewed 26 patients with brain stem tumors. None had a pre-treatment tissue diagnosis. Four of the 20 treated patients are alive from 22 months to 12 years later, representing no improvement from a preceding series in the same centre.     

Brain tumors: detection and typing by use of CPMG sequences and in vivo T2 measurements

A spin-echo sequence with 24 echoes (Carr-Purcell-Meiboom-Gill sequence) was evaluated to determine the usefulness of magnetic resonance (MR) in detecting and typing brain tumors. The TEs in these examinations were between 28 and 346 msec, and the TR was 860, 1260, or 1660 msec. The results of the MR examination of 32 histopathologically proved tumors are presented. All but one tumor could be detected by MR. Tumors generally were obvious on MR due to the higher contrast enhancement of these lesions, especially with a TE longer than 100 msec. T2 values calculated from an eight-point fit, however, did not allow discrimination of different tumors, nor did they allow differentiation between tumor, inflammatory tissue, and demyelination.