Apparent diffusion coefficient restriction in the white matter: going beyond acute brain territorial ischemia

BACKGROUND: Reduction of apparent diffusion coefficient (ADC) values in white matter is not always ischaemic in nature. METHODS: We retrospectively analysed our MRI records featuring reduced ADC values in the centrum semiovale without grey matter involvement or significant vasogenic oedema. RESULTS: Several conditions showed the aforementioned MR findings: moose-horn lesions on coronal images in X-linked Charcot-Marie-Tooth disease; small fronto-parietal lesions in Menkes disease; marked signal abnormalities in the myelinised regions in the acute neonatal form of maple syrup urine disease; strip-like involvement of the corpus callosum in glutaric aciduria type 1; persistent periventricular parieto-occipital abnormalities in phenylketonuria; diffuse signal abnormalities with necrotic evolution in global cerebral anoxia or after heroin vapour inhalation; almost completely reversible symmetric fronto-parietal lesions in methotrexate neurotoxicity; chain-like lesions in watershed ischaemia; splenium involvement that normalises in reversible splenial lesions or leads to gliosis in diffuse axonal injury. CONCLUSION: Neuroradiologists must be familiar with these features, thereby preventing misdiagnosis and inappropriate management

Concerns about anti-angiogenic treatment in patients with glioblastoma multiforme

BACKGROUND: The relevance of angiogenesis inhibition in the treatment of glioblastoma multiforme (GBM) should be considered in the unique context of malignant brain tumours. Although patients benefit greatly from reduced cerebral oedema and intracranial pressure, this important clinical improvement on its own may not be considered as an anti-tumour effect. DISCUSSION: GBM can be roughly separated into an angiogenic component, and an invasive or migratory component. Although this latter component seems inert to anti-angiogenic therapy, it is of major importance for disease progression and survival. We reviewed all relevant literature. Published data support that clinical symptoms are tempered by anti-angiogenic treatment, but that tumour invasion continues. Unfortunately, current imaging modalities are affected by anti-angiogenic treatment too, making it even harder to define tumour margins. To illustrate this we present MRI, biopsy and autopsy specimens from bevacizumab-treated patients. Moreover, while treatment of other tumour types may be improved by combining chemotherapy with anti-angiogenic drugs, inhibiting angiogenesis in GBM may antagonise the efficacy of chemotherapeutic drugs by normalising the blood-brain barrier function. SUMMARY: Although angiogenesis inhibition is of considerable value for symptom reduction in GBM patients, lack of proof of a true anti-tumour effect raises concerns about the place of this type of therapy in the treatment of GBM

DIAGNOSTIC AND INTERVENTIONAL RADIOLOGY

Magnetic resonance imaging (MRI) has increasingly new applications in neuro-otology. The aim of this review was to summarize MRI applications in neuro-otology and make a correlation between neuro-otologic anatomy and MR images. Different MRI techniques have been described in the imaging of different neuro-otologic structures. In particular, we discuss the effectiveness, indications, and techniques of MRI in the demonstration of neuro-otologic tracts and their related pathologies. MRI should be the first choice imaging modality for the evaluation of retrocochlear pathologies

Interrelationship between Liver Hemodynamics and Tumor Metabolism in Liver Metastases: Diagnostic Value of Doppler Perfusion Index Revisited

It should be expected that the hepatic blood flow increase in the cases with liver metastasis. We aimed to find out if there is a correlation between Doppler parameters and hepatic metabolic activity in oncology patients. 35 patients with hepatic metastases who were identified by 18F-fluorodeoxyglucose positron emission tomography scan and assessed with Doppler ultrasound were included in this prospective study. Patients with hepatic disease, cardiac dysfunction, dehydration, history of alcoholism, intake of antihypertensive or vasoactive medication were excluded. Volume flow of the proper hepatic artery and the portal vein were measured in the hepatoduodenal ligament by Doppler sonography. Doppler perfusion index (the ratio of the hepatic artery flow to the total liver blood flow) and flow volumes of 31 age matched subjects were compared. Both flow of the proper hepatic artery and portal vein were found to be significantly higher in patients with liver metastasis. The mean Doppler perfusion index value was 0.2 ± 0.13 in hepatic metastases whereas 0.13 ± 0.05 in control group. Doppler perfusion index was significantly higher in liver metastases (p=0.008). A positive correlation was found between the maximum standardized uptake value of the liver and flow volume of the proper hepatic artery (r=0.774, p=0). Blood flow of the proper hepatic artery and Doppler perfusion index correlates with hepatic standardized uptake value. Flow measurements of the liver may become an important parameter for selecting patients for further positron emission tomography scan and following-up the response after systemic and local therapeutic procedures