MR Imaging in Cerebral Gliomas

A comparative analysis between MR examinations and histopathologic whole-brain sections regarding tumour components was performed in 5 brain specimens from patients with malignant glial brain tumours. All cases were examined with MR imaging in vitro and in 2 cases a close comparison with the MR examinations in vivo was also possible. The most homogeneous hypercellular area in malignant gliomas, giving the highest tumour grade, was not visualised on MR imaging as an isolated entity, either in vitro or in vivo. The most conspicuous tumour component, reflecting the heterogeneity of malignant gliomas, was necrosis. This feature was best depicted in the T2WI. In 4 of 5 cases, distant tumour spread of benign-looking tumour cells was found in areas visualised as normal on T2WI, outside the margins of the peritumoural oedema. In 2 cases, estimation of water content was performed immunohistochemically and a close correlation was found in each case between peritumoural and periventricular hyperintensity on T2WI and areas of pallor on the haematoxylin-eosin-stained whole-brain sections. These areas corresponded to microscopical oedema. MR imaging reflects underlying heterogeneous histopathology in malignant gliomas. The degree of malignancy of the lesion as a whole can thus be assessed by MR imaging. However, the method does not allow malignant gliomas to be correctly delineated.

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 with 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 used 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.

Measurements of T1 and T2 over Time in Formalin-Fixed Human Whole-Brain Specimens

Abstract

T1 and T2 were measured in 5 formalin-fixed human whole-brain specimens as a function of time. Gray matter/white matter contrast reversal was observed around the 4th day and was considered to be due to the greater decrease in T1 in gray than in white matter. A possible explanation for this is that the decomposition of the myelin phospholipid structure by formalin somewhat counteracts the general reductive effect of the fixation procedure on relaxation times.

Three-dimensional time-of-flight (3D TOF) magnetic resonance angiography (MRA) and contrast-enhanced MRA of intracranial aneurysms treated with platinum coils

BACKGROUND

Contrast-enhanced magnetic resonance angiography (CE-MRA) is less prone to flow-related signal intensity loss than three-dimensional time-of-flight (3D TOF) MRA and may therefore be more sensitive for detection of residual patency in platinum coil-treated intracranial aneurysms.

PURPOSE

To compare MRA and CE-MRA in the follow-up of intracranial aneurysms treated with platinum coils.

MATERIAL AND METHODS

CE-MRA and 3D TOF MRA (pre- and postcontrast injection) of the intracranial vasculature was performed at 1.5T in 38 patients (47 aneurysms) referred for DSA in the follow-up of coiled intracranial aneurysms.

RESULTS

DSA showed aneurysm patency in 22/47 investigations. Patent aneurysm components were observed with CE-MRA in 18/22 cases, and with 3D TOF MRA in 21/22 cases. There was no significant difference in patent aneurysm component size between CE-MRA and 3D TOF MRA. In addition, CE-MRA showed six, 3D TOF MRA before contrast injection showed seven, and 3D TOF MRA after contrast injection showed eight cases with patent aneurysm components not observed on DSA.

CONCLUSION

3D TOF MRA was highly sensitive for detection of patent aneurysm components, and at least as sensitive as CE-MRA. Residual aneurysm patency seems to be better visualized with MRA than with DSA in some cases.

The establishment of endovascular aneurysm coiling at a neurovascular unit: report of experience during early years

The treatment of cerebral aneurysms is changing from surgical clipping to endovascular coiling (EVC) in many neurovascular centres. The aim of this study was to evaluate the technical results and clinical outcome at 6 months in a consecutive series of subarachnoid hemorrhage (SAH) patients treated with EVC, in a situation when the EVC had been established very rapidly as the first line of treatment at a neurovascular centre. The patient material comprised 239 SAH patients (155 women and 84 men, mean age 55 years, age range 16-81) allocated to EVC as the first line of treatment in the acute stage (within 3 weeks of rupture) between September 1996 and December 2000. Clinical grade on admission was Hunt & Hess (H&H) I and II in 42%, H&H III in 25% and H&H grade IV and V in 33% of the patients. The aneurysm was located in the anterior circulation in 82% of the cases. EVC was performed on days 0-3 in 77% of the cases. EVC of the target aneurysm was able to be completed in 222 patients (93%). Complete occlusion was achieved in 126 patients (53%). Procedural complications occurred in 39 patients (16%). Favourable clinical outcome was observed in 57%, severe disability in 28% and poor outcome in 14% of the patients. Favourable outcome was achieved in 77% of H&H I and II patients and in 43% of H&H III-V patients. The multivariate logistic regression analysis revealed that younger age, good neurological grade on admission, absence of intracerebral hematoma and intraventricular hematoma respectively, ICA-PcomA aneurysm location, later treatment and absence of complications were significant predictors of favourable outcome. After interventional training and installation of the X-ray system, the introduction and establishment of EVC at a neurovascular unit can be done in a short period of time and with favourable results. Future studies must concentrate on identifying factors of importance for the choice of interventional or surgical therapy. The results of this study indicate that endovascular therapy may be particularly beneficial in poor-grade patients and in patients with aneurysms in the ICA-PcomA territory.

Clinical outcome after endovascular coil embolization in elderly patients with subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) is not an unusual disease in an elderly population. The clinical outcome has improved over time. It has been suggested that elderly SAH patients would benefit from endovascular aneurysm treatment. The aim of this study was to evaluate technical results and clinical outcome in a series of elderly SAH-patients treated with endovascular coil embolization. Sixty-two patients (> or = 65 years) presenting with aneurysmal SAH underwent early endovascular coil embolization at Uppsala University Hospital between September 1996 and December 2000. In all 62 cases included in the study, endovascular coil embolization was considered the first line of treatment. Admission variables, specific information on technical success, degree of occlusion and procedural complications, and outcome figures were recorded. Clinical grade on admission was Hunt and Hess (H&H) I-II in 39%, H&H III in 27% and H&H IV-V in 34% of the patients. The proportion of posterior circulation aneurysms was 24%. Coil embolization was successfully completed in 94%. The degree of occlusion of the treated aneurysm was complete occlusion in 56%, neck remnant in 21%, residual filling in 11%, other remnant in 5% and not treated in 6%. The rate of procedural complications was 11%. Outcome after 6 months was favorable in 41%, severe disability in 36% and poor in 22%. Favorable outcome was achieved in 57% of the H&H I-II patients, 47% of the H&H III patients and 17% of the H&H IV-V patients. Endovascular aneurysm treatment can be performed in elderly patients with SAH with a high level of technical success, acceptable aneurysm occlusion results, an acceptable rate of procedural complications and fair outcome results.

Traitement par vincristine des hémangiomes graves du nourrisson

AIM

To evaluate the efficacy of vincristine treatment for function- and life-threatening hemangiomas.

PATIENTS AND METHOD

Nine infants, eight girls and one boy, received vincristine treatment (VCR) for endangering hemangiomas. In six cases, the hemangiomas involved head and neck in a segmental unilateral or bilateral distribution (3/6 also had laryngeal and 2/6 tracheal location causing respiratory distress, 5/6 had eyelid and orbital involvement); one infant had disseminated neonatal hemangiomatosis (skin, liver, kidney); two infants had liver hemangiomas with cardiac failure. VCR was prescribed after failure of high-dosage corticosteroid treatment in six, and of both corticosteroids and interferon alpha 2b (5 months) in one; two infants received VCR as first line treatment.

RESULTS

A dosage of 1 mg/m(2) IV injection was delivered, with weekly injections first, and then tapering, increasing the interval between injections, depending on the clinical response. The nine infants received from 5 to 25 injections (average: 16), for a length of treatment of 1.5-8 months (average: 5.5 months). In seven patients a clear clinical response was observed at the end of the first month of treatment, while a slow protracted response was noted in two. Transient mild side effects were present in four patients.

DISCUSSION

Corticosteroid treatment, although a worldwide recognized treatment of problematic hemangiomas, cannot always control the growth of alarming hemangiomas. Interferon alpha 2a and 2b have proven a 90% effectiveness: treatment for cortico-resistant, function- and life-threatening, hemangiomas.

Treatment of distal aneurysms of the cerebellar arteries by intraaneurysmal injection of glue

Distal aneurysms of the cerebellar arteries are associated with a poor prognosis, as surgery or embolization with GDCs is very difficult. We report our experience with a new therapeutic method involving intraaneurysmal injection of glue. Three aneurysms were catheterized with a flow-guided microcatheter, and glue was slowly injected into the aneurysms. In two cases, treatment resulted in total occlusion of the aneurysm with preservation of the parent artery. In one case, the aim was to occlude both the aneurysm and parent artery.

[52 patients with cystic lymphatic vascular malformations. Percutaneous sclerotherapy--simple, fast and repeatable]

Cystic lymphatic malformations are haemodynamically inactive vascular malformations that never regress. During a nine-year period, 52 patients with cervico-facial superficial cystic lymphatic malformations underwent percutaneous sclerotherapy with Ethibloc (a corn-based alcohol derivative). In 57 percent (30/52) of cases, the outcome of sclerotherapy alone was excellent or good: in 19 percent (10/52), the procedure had to be combined with surgery for aesthetic reasons; and in the remaining 24 percent (12/52), the treatment failed. The results suggest percutaneous sclerotherapy with Ethibloc to be safe and effective, and that it is to be recommended as the treatment of choice in cases of superficial cystic lymphatic malformations.

Intracranial aneurysms: endovascular treatment with mechanical detachable spirals in 60 aneurysms

PURPOSE

To evaluate preliminary results with endovascular treatment (EVT) of intracranial aneurysms with mechanical detachable spirals.

MATERIALS AND METHODS

EVT with spirals was attempted in 57 patients with 60 aneurysms (47 berry, nine large, and four giant aneurysms). Thirty-seven patients had subarachnoid hemorrhage (three of whom were also treated for associated aneurysm), nine were asymptomatic, six had headache, three had mass effect, and two had neurologic deficits.

RESULTS

EVT with the spirals was achieved in 55 (92%) of the 60 aneurysms. Of 42 treated berry aneurysms and 13 treated large and giant aneurysms, 33 berry and nine large and giant aneurysms underwent 3-month angiographic follow-up. Complete occlusion was attained in 23 berry and four large and giant aneurysms, subtotal occlusion (doubtful or obvious small neck remnant) was obtained in eight berry and four large and giant aneurysms, and incomplete occlusion was obtained in two berry aneurysms and one giant aneurysm. These results were obtained after one procedure in 21 patients, after two procedures in 19 patients, and after three procedures in two patients. Seven patients had complications that necessitated infusion of urokinase. Permanent neurologic deficits were found in three. There were no deaths.

CONCLUSION

Good results were obtained with EVT of intracranial aneurysms with mechanical detachable spirals. These spirals are characterized by rapid detachment and low cost.

MR imaging in cerebral gliomas. Tissue component analysis in correlation with histopathology of whole-brain specimens

A comparative analysis between MR examinations and histopathologic whole-brain sections regarding tumour components was performed in 5 brain specimens from patients with malignant glial brain tumours. All cases were examined with MR imaging in vitro and in 2 cases a close comparison with the MR examinations in vivo was also possible. The most homogeneous hypercellular area in malignant gliomas, giving the highest tumour grade, was not visualised on MR imaging as an isolated entity, either in vitro or in vivo. The most conspicuous tumour component, reflecting the heterogeneity of malignant gliomas, was necrosis. This feature was best depicted in the T2WI. In 4 of 5 cases, distant tumour spread of benign-looking tumour cells was found in areas visualised as normal on T2WI, outside the margins of the peritumoural oedema. In 2 cases, estimation of water content was performed immunohistochemically and a close correlation was found in each case between peritumoural and periventricular hyperintensity on T2WI and areas of pallor on the haematoxylin-eosin-stained whole-brain sections. These areas corresponded to microscopical oedema. MR imaging reflects underlying heterogeneous histopathology in malignant gliomas. The degree of malignancy of the lesion as a whole can thus be assessed by MR imaging. However, the method does not allow malignant gliomas to be correctly delineated.

Measurements of T1 and T2 over time in formalin-fixed human whole-brain specimens

T1 and T2 were measured in 5 formalin-fixed human whole-brain specimens as a function of time. Gray matter/white matter contrast reversal was observed around the 4th day and was considered to be due to the greater decrease in T1 in gray than in white matter. A possible explanation for this is that the decomposition of the myelin phospholipid structure by formalin somewhat counteracts the general reductive effect of the fixation procedure on relaxation times.

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.