Multiple cerebral arteriovenous malformations (AVMs)

Summary From our series of 203 patients with cerebral vascular lesions, 18 (9%) could be included in the multiple arteriovenous malformation category. There were five patients with Rendu-Osler-Weber, one with Wyburn-Mason syndromes and two with concurrent arteriovenous malformations. The remaining ten patients (4%) had multiple brain arteriovenous malformations. Careful angiography with magnification is necessary to try to diagnose multiple brain AVMs, since these sometimes become apparent only after embolization of a larger dominant AVM. The incidence, of multiple brain arteriovenous malformations is likely to have been underestimated due to the failure to recognize microarteriovenous malformations associated with larger arteriovenous malformations.     

大脑中动脉闭塞的超选择性动脉内溶栓治疗

目的 :探讨超选择性动脉内溶栓治疗急性大脑中动脉闭塞的价值。方法 :经股动脉穿刺 ,将微导管超选择插至闭塞血管远端或置于血块内注入尿激酶 (UK)进行溶栓治疗。 12名急性大脑中动脉闭塞患者接受了溶栓治疗。结果 :8例获得大脑中动脉完全再通 ,3例获得部分再通 ,1例没有发生再通。随访 5个月 ,6人生活能完全自理 ,2人生活部分自理 ,3人无法生活自理 ,1人死亡。结论 :超选择性动脉内溶栓治疗可作为急性大脑中动脉闭塞可供选择的治疗方法之一。     

Predictors for basal ganglia viability after mechanical thrombectomy in proximal middle cerebral artery occlusion

Background/purposeIn acute proximal middle cerebral artery (MCA) occlusion covering the lenticulostriate arteries (LSA), ischemic tolerance of basal ganglia is limited due to supposed lack of collateral supply. However, in several patients, basal ganglia (BG) infarction was absent after successful mechanical thrombectomy (MTE). Purpose of our study was to evaluate predictors for BG viability in stroke patients despite prolonged MCA mainstem occlusion.Material/methodsWe retrospectively reviewed all stroke patients from our local registry with MCA mainstem occlusion after mechanical thrombectomy between November 2009 and October 2016. All patients underwent non-enhanced post-interventional cranial CT imaging (NCCT) and were classified according to 6 patterns of BG viability: complete: putamen (P) and globus pallidus (GP); partial: P or GP, and combination of complete or partial BG and/or adjacent white matter/cortical (WMC) viability. We compared viability patterns with respect to pre-interventional stroke imaging including NCCT, CT-angiography (CTA), CT perfusion (CTP); demographics, pre- and intra-procedural data and occurrence of post-procedural intracerebral hematoma (ICH). CTP imaging of the affected and contralateral BG-territories were obtained separately and CTA-collateral score (CS) was assessed.ResultsA significant correlation between higher collateral score and viability of GP (OR = 1.949; p = .011), P (OR = 2.039, p = .011), and the combination of GP, P and WMC (OR = 2.767, p = .007) was revealed. Higher relative CBV ratio (rCBVR) was significantly associated with viability of the pattern GP + WMC (univariate: OR = 3.160, p = .014; multivariate: OR = 6.058; p = .021).ConclusionCTA collateral score and rCBVR were predictive for BG viability in stroke patients after successful MTE in prolonged complete MCA-mainstem and LSA occlusion.     

Large-body radiation doses following radioiodine therapy

In accordance with the recommendations of the International Radiological Protection Commission, the current maximum acceptable radiation dose limits for members of the public have been reduced to 1 mSv in the United States, Canada, and European Union countries including the United Kingdom. This has had a significant impact on radiation protection guidelines for contacts of patients treated with 131I. Many previous recommendations have relied upon models which may overestimate dose rates at short distances. We therefore undertook measurements of 131I dose rates using adult and infant phantoms that more accurately reflected true geometry. Effective dose calculations and patient contact restrictions were then derived from these direct dose measurements. Doses received by the adult phantom were measured at three distances (contact, 1.0 m, 2.0 m) and doses received by the infant phantom were measured at contact in two orientations (adult cradling infant over shoulder and at waist). The doses measured were significantly lower than previously predicted for the adult and infant phantom. Our measurements suggest that patient contact restrictions could be made less stringent than those currently in widespread use.     

Radiation pneumonitis following multi-field radiation therapy

The mechanisms of radiation pneumonitis have not been established. In a study on multi-field radiation therapy for lung cancer, one patient developed severe radiation pneumonitis even though the target volume was small. Radiation therapy was performed at a dose of 75 Gy in 50 fractions over five weeks. High-density areas conforming to the radiation field were observed by high-resolution CT. They were observed in the irradiated volume at doses under 20 Gy in the contralateral lung as well as in the ipsilateral lung.     

Abnormalities on chest radiographs following radiation therapy for breast cancer

The aim of this study was to study pulmonary radiological abnormalities with chest radiography following different radiotherapy (RT) techniques for breast cancer with respect to regions and density, and their association with pulmonary complications and reduction in vital capacity (VC). Chest radiographs were performed 5 months following local or loco-regional RT in 167 breast cancer patients. The radiological abnormalities were analysed with a classification system originally proposed by Arriagada and evaluated according to increasing density (0–3) and affected lung regions (apical–lateral, basal–lateral, central–parahilar). The highest-density grades in each region were added together to form scores ranging from 0 to 9. The patients were monitored for RT-induced pulmonary complications. The VC was measured prior to and 5 months following RT. An independent evaluation of 51 patients was performed by a second radiologist to control the reproducibility of the classification system. Increasing scores were associated with loco-regional RT and pulmonary complications (P < 0.001). The mean reduction of VC for patients scoring 0–3 (–30 ml) vs 4–9 (–161 ml) was not statistically significant (P = 0.10). Scores of 4–9 were more frequently observed in older patients (P < 0.001). The independent evaluations by two radiologists revealed good agreement (P < 0.001) and no systematic inter-observer variation. Radiological abnormalities on chest radiographs, scored according to Arriagada, can be used as an objective end point for RT-induced pulmonary side effects in breast cancer. Received: 4 February 1999; Revision received: 1 April 1999; Accepted: 5 May 1999     

Neurological changes following radiation therapy for head and neck tumours

Radiation therapy is widely used in the treatment of head and neck tumours either as a primary form of treatment or a supplementary modality. Although the benefits of radiation therapy are well established, this treatment modality is not without untoward consequences and complications. The intent of this paper is to highlight the neurological complications that may follow the treatment for head and neck malignancies, in particular, following radiation therapy for nasopharyngeal carcinoma.     

Survival with brain metastases following radiation therapy

The onset of intracranial metastases is a common development during the course of malignancy. The treatment of these patients represents a significant workload in any radiation oncology department. Much debate has occurred regarding the most appropriate fractionation schedules employed given the perception of limited life expectancy and symptomatic relief following cranial radiation. The aim of this study was to identify the spectrum of primary sites in patients developing intracranial metastases and to assess survival postradiation for the group overall and for selected subgroups. The records of 378 patients undergoing palliative cranial radiation in the years 1993-1998 at Sydney's Mater and Royal North Shore hospitals were analysed retrospectively. Major primary sites were lung (42%), breast (18%), colorectal (9%), melanoma (7%), and unknown primary (7%). Overall median survival post-treatment was 3 months. Lung cancer patients showed a median survival of 6 months, breast 5 months, colorectal 4 months and melanoma 3 months. Long-term survivors were noted with up to 15% of certain groups alive beyond 12 months and 2% alive at 24 months. Multivariate analysis revealed improved survival in patients undergoing resection, and those receiving higher dose radiation justifying a more aggressive approach in selected patients.     

Angiographic follow-up of large cerebral AVMs incompletely embolized with isobutyl-2-cyanoacrylate

This study evaluated the long-term angiographic results in large cerebral arteriovenous malformations (AVMs) partially embolized with isobutyl-2-cyanoacrylate. Preembolization, immediate postembolization, and long-term follow-up angiograms were performed in 30 large, partially embolized brain AVMs. Particular attention was paid to the relative size of the residual AVM nidus and the embolized arterial feeders, to recruitment of new feeders, to the size of residual draining veins, and to the speed of arteriovenous shunt. Nine cases with less than 50% AVM nidus obliteration showed no significant morphologic changes. In 18 cases with 50-75% obliteration of the AVM nidus, 11 (61.1%) showed no significant changes, six (33.3%) showed enlargement of the AVM nidus, and one (5.5%) evolved to complete angiographic obliteration. In three cases with 75-99% AVM nidus obliteration, one remained unchanged, one showed an increase in the size of the AVM nidus, and one evolved to complete obliteration. Evaluation by plain film, CT, and cerebral angiography of the isobutyl-2-cyanoacrylate deposits showed that when the polymer was positioned predominantly in arterial feeders there was invariably reconstitution of the AVM nidus through leptomeningeal, deep medullary, and/or dural collaterals. This phenomenon did not occur when the isobutyl-2-cyanoacrylate was deposited mainly in the AVM nidus.     

Evaluation of cerebral hemodynamics by 123I-IMP in cerebral AVMs before and after operation by using SPECT

To evaluate cerebral hemodynamics by N-isopropyl-p-[123I]-iodoamphetamine (123I-IMP) preoperative and postoperative (after 1 day, and after 7-10 days) regional cerebral blood flow scan, 6 arteriovenous malformations (AVMs) which performed total removal operations were studied by using a ring type SPECT "HEADTOME". We performed the dynamic scan just after the intravenous injection of 222 MBq (6 mCi) of 123I-IMP, then the static scan 20 minutes after the intravenous injection. In preoperative dynamic scans of all cases, only the first frame image showed the increased activity on the nidus probably because of the blood pool. Preoperative static scans of all cases showed the remarkable decreased activity on the nidus, and decreased activity surrounding the nidus probably because of the peripheral steal phenomenon. In postoperative scan of the next day, 4 out of 6 cases showed the transient decreased peripheral steal, particularly 2 out of those 4 cases showed the transient hyperperfusion probably because of the normal perfusion pressure breakthrough (NPPB). And, 2 out of 6 cases showed transient peripheral low perfusion on much larger area than those of the preoperative scans probably because of the focal brain damages and edemas. We conclude that 123I-IMP SPECT on AVM is very useful to decide the indication of the removal operation, and to estimate the postoperative risk, and to evaluate the preoperative and postoperative cerebral hemodynamic changes in the peripheral area of AVM.