Clinical applications of dynamic susceptibility contrast perfusion-weighted MR imaging in brain tumours.

Magnetic resonance imaging (MRI) with a dynamic susceptibility contrast perfusion-weighted imaging (DSC-PWI) sequence to study brain tumours provides information on the haemodynamic characteristics of the neoplastic tissue. Brain perfusion maps and calculation of perfusion parameters, such as relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV) and mean transit time (MTT) allow assessment of vascularity and angiogenesis within tumours of the central nervous system (CNS), thus providing additional information to conventional MRI sequences. Although DSC-PWI has long been used, its clinical use in the study of brain tumours in daily clinical practice is still to be defined. The aim of this review was to analyse the application of perfusion MRI in the study of brain tumours by summarising our personal experience and the main results reported in the literature.

Intracranial hypotension and PRES: case report.

We report a case of a woman presenting, 7 days after epidural analgesia for a caesarean section, to the emergency room for a worsening of the headache and tonico-clonic seizures. MRI showed alterations suggestive of the presence of intracranial hypotension (IH) as well as evidence of posterior reversible encephalopathy syndrome (PRES). She was treated with a blood patch which leads to the prompt regression of the clinical symptoms and follow-up MRI, after 15 days, showed complete resolution of radiological alterations. The possible pathogenetic relationship between IH, secondary to the inadvertent dural puncture, and PRES is discussed. We suggest that venous stagnation and hydrostatic edema, secondary to intracranial hypotension, probably played a crucial role in the pathogenesis of PRES.

The role of time-resolved imaging of contrast kinetics (TRICKS) magnetic resonance angiography (MRA) in the evaluation of head-neck vascular anomalies: a preliminary experience.

OBJECTIVES: In this preliminary report, we describe our experience with time-resolved imaging of contrast kinetics-MR angiography (TRICKS-MRA) in the assessment of head-neck vascular anomalies (HNVAs). METHODS: We prospectively studied six consecutive patients with clinically suspected or diagnosed HNVAs. All of them underwent TRICKS-MRA of the head and neck as part of the routine for treatment planning. A digital subtraction angiography (DSA) was also performed. RESULTS: TRICKS-MRA could be achieved in all cases. Three subjects were treated based on TRICKS-MRA imaging findings and subsequent DSA examination. In all of them, DSA confirmed the vascular architecture of HNVAs shown by TRICKS-MRA. In the other three patients, a close follow up to assess the evolution of the suspected haemangioma was preferred. CONCLUSIONS: TRICKS sequences add important diagnostic information in cases of HNVAs, helpful for therapeutic decisions and post-treatment follow up. We recommend TRICKS-MRA use (if technically possible) as part of routine MRI protocol for HNVAs, representing a possible alternative imaging tool to conventional DSA.

Intrafamilial variability in hereditary spastic paraplegia associated with an SPG4 gene mutation.

The authors studied a family with pure autosomal dominant spastic paraplegia (ADHSP) that showed a marked intrafamilial variability in both age at onset and clinical severity, ranging from severe congenital presentation to mild involvement after age 55. They found a novel mutation in the SPG4 gene, which segregates with the disease in six patients. The mutation affects the consensus donor splice site of SPG4 intron 16, resulting in a premature termination codon at amino acid 578. The data confirm the pathologic significance of SPG4 mutations in pure ADHSP and add to the list of known SPG4 allelic variants.

Mitochondrial myopathy, parkinsonism, and multiple mtDNA deletions in a Sephardic Jewish family.

The authors describe a family of Sephardic Jews with progressive external ophthalmoparesis, skeletal muscle weakness, and parkinsonism. Autosomal recessive inheritance was suggested by many consanguineous marriages, although a dominant disorder could not be excluded. No linkage to known progressive external ophthalmoparesis locus was found. The presence of cytochrome c oxidase-negative ragged-red fibers, biochemically reduced respiratory chain complexes, and multiple mitochondrial DNA deletions in muscle biopsies from four patients suggested a new mitochondrial disorder of intergenomic communication.

Early angiographic and CT findings in patients with hemorrhagic infarction in the distribution of the middle cerebral artery.

Hemorrhagic infarction subsequent to ischemic brain damage, even if small, slight, or marbled, can be detected by CT. The mechanisms that give rise to this transformation in humans are not well elucidated. Previous reports indicate that hemorrhagic infarction is most common in embolic stroke and large infarcts, and can worsen the clinical state of ischemic patients. We examined 36 patients with supratentorial ischemic signs and symptoms within the first hours after onset. CT was used to judge if hypodensity on early CT studies might predict the development of hemorrhagic infarction. Angiography was used to observe the site of arterial occlusion, the state of collateral circulation, and the mechanisms of late reperfusion. Hemorrhagic infarction was present in 18 of our 36 patients. Angiography revealed occlusion of the middle cerebral artery or internal carotid artery (three cases) in all patients. Hypodensity was present on early CT studies in all of the 18 patients who developed hemorrhagic infarction. The finding of hypodensity on CT studies performed soon after embolic ischemic stroke is strongly predictive of hemorrhagic transformation.

Cerebral hemodynamics on MR perfusion images before and after bypass surgery in patients with giant intracranial aneurysms.

BACKGROUND AND PURPOSE: Preoperative assessment of the anatomy and dynamics of cerebral circulation for patients with giant intracranial aneurysm can improve both outcome prediction and therapeutic approach. The aim of our study was to use perfusion MR imaging to evaluate cerebral hemodynamics in such patients before and after extraintracranial high-flow bypass surgery. METHODS: Five patients with a giant aneurysm of the intracranial internal carotid artery underwent MR studies before, 1 week after, and 1 month after high-flow bypass surgery. We performed MR and digital subtraction angiography, and conventional and functional MR sequences (diffusion and perfusion). Surgery consisted of middle cerebral artery (MCA)-internal carotid artery bypass with saphenous vein grafts (n = 4) or MCA-external carotid artery bypass (n = 1). RESULTS: In four patients, MR perfusion study showed impaired hemodynamics in the vascular territory supplied by the MCA of the aneurysm side, characterized by significantly reduced mean cerebral blood flow (CBF), whereas mean transit time (MTT) and regional cerebral blood volume (rCBV) were either preserved, reduced, or increased. After surgery, angiography showed good canalization of the bypass graft. MR perfusion data obtained after surgery showed improved cerebral hemodynamics in all cases, with a return of CBF index (CBFi), MTT, and rCBV to nearly normal values. CONCLUSION: Increased MTT with increased or preserved rCBV can be interpreted as a compensatory vasodilatory response to reduced perfusion pressure, presumably from compression and disturbed flow in the giant aneurysmal sac. When maximal vasodilation has occurred, however, the brain can no longer compensate for diminished perfusion by vasodilation, and rCBV and CBFi diminish. Bypass surgery improves hemodynamics, increasing perfusion pressure and, thus, CBFi. Perfusion MR imaging can be used to evaluate cerebral hemodynamics in patients with intracranial giant aneurysm.

No differences in corpus callosum size by sex and aging. A quantitative study using magnetic resonance imaging.

To identify normal variations in the magnetic resonance imaging appearances of the corpus callosum with regard to sex and age, a prospective study was performed in 130 normal subjects. Callosal measurements were calculated by morphometric analysis. There were no significant sex differences in corpus callosum area or the callosal subregions. The absolute area did not decrease significantly with aging in normal males or females. However, age-related changes of callosal configuration were shown by a decrease in the ratio of the rostrum and genu to the splenium.

The usefulness of dynamic CT in patients with aneurysm of Willis circle. Comparative study with the angiography.

The diagnosis of cerebral aneurysm is currently based on the angiographic data. We have tried to evaluate the usefulness of a less-invasive examination, such as the dynamic-CT, in the diagnosis of intracranial aneurysm and of the possible and concomitant subaracnoid haemorrhage. The CT examination is useful in the diagnosis of both subarachnoid haemorrhage and giant trombosed aneurysm. It is less reliable than the angiography as regard to aneurysm of small dimension.

Neurovascular headache and occipital neuralgia secondary to bleeding of bulbocervical cavernoma.

It has recently been suggested that the trigeminocervical complex plays a crucial role in the pathophysiology of neck discomfort that accompanies migraine attacks. Clinical and neurophysiological data have shown that pain within the occipital area may be transmitted by the first trigeminal branch, which supports an anatomical and functional link between cervical and trigeminal modulation of peripheral afferents. We describe a patient with an acute symptomatic migraine attack and chronic occipital neuralgia, both due to bleeding of a bulbocervical cavernoma. The clinical presentation is also discussed and related to recent scientific data on the role of the trigeminocervical complex in both the clinical picture and underlying pathophysiological mechanisms of cervical and head pain.

The role of MRI in dementia.

Neuroimaging techniques aimed at studying structural changes of the brain may provide useful information for the diagnosis and the clinical management of patients with dementia. Magnetic resonance imaging (MRI) may show abnormalities amenable to surgical treatment in a significant percentage of patients with cognitive impairment. MRI may also assist the differential diagnosis in dementia associated with metabolic or inflammatory diseases.MRI has the potential to detect focal signal abnormalities which may assist the clinical differentiation between Alzheimer's disease (AD) and vascular dementia (VaD). Severe temporal atrophy, hyperintensities involving the hippocampal or insular cortex, and gyral hypointense bands are more frequently noted in AD. Basal ganglionic/thalamic hyperintense foci, thromboembolic infarctions, confluent white matter and irregular periventricular hyperintensities are more common in VaD. The high sensitivity of MRI in detecting T2 hyperintense lesions and the low specificity off white matter lesions have resulted in a poor correlation between MRI findings and both neuropathological and clinical manifestations. In particular, MRI has disclosed a series of white matter focal changes in the elderly population, which are not necessarily associated with cognitive dysfunction. The recent advent of a new MRI method sensitive to the microstructural changes of white matter, the so-called diffusion tensor imaging, may be helpful in correlating clinical manifestations with white matter abnormalities.

Reversible diffusion MRI abnormalities and transient mutism after liver transplantation.

Transient mutism was observed in a liver transplant patient under immunosuppressant therapy with cyclosporine A and antifungal prophylaxis with amphotericin B. Fluid-attenuated inversion recovery and diffusion-weighted images revealed reversible bilateral symmetric hyperintensity located in the frontal motor cortex and corticospinal tracts. These MRI abnormalities may be caused by acute edema, possibly a combination of cytotoxic and vasogenic edema, which resolved with a prompt change in therapy.

Sporadic Creutzfeldt-Jakob disease without dementia at onset: clinical features, laboratory tests and sequential diffusion MRI (in an autopsy-proven case).

A rapidly progressing dementia, followed by focal neurological signs, and evidence of periodic sharp wave complexes (PSWC) in the EEG may lead to the clinical suspicion of Creutzfeldt-Jakob disease (CJD). Different clinical variants of CJD have been described in the past, with prominent extrapyramidal or occipital lobe involvement, all included in the sporadic form of CJD (sCJD). Familiar and iatrogenic forms of CJD are also known. More recently a new variant has been described, vCJD, casually linked to bovine spongiform encephalopathy (BSE) and it has attracted increasing attention toward each form of rapidly progressing dementia; likewise the differential diagnosis between sCJD vs. vCJD is not always easy. Magnetic resonance imaging (MRI) too seems to have a peculiar role in differentiating sCJD from vCJD, even if the role of MRI in the diagnosis of CJD is still debated. Diffusion MRI is expected to play an important role in the clinical setting of CJD, contributing to formulation of an early diagnosis, especially in cases with unusual clinical presentation. In fact, the sensitivity of diffusion MRI is superior to that of conventional MRI (T1, T2, FLAIR) in detecting specific basal ganglia and cortical abnormalities early in the course of CJD and these abnormalities correlate well with areas of the most severe and characteristic neuropathological changes. We describe a case of autopsy-proven sCJD, with an unusual clinical course without dementia as a presenting symptom and discuss the role of diffusion MRI and laboratory tests in making an early diagnosis.

Pleomorphic xanthoastrocytoma with CT and MRI appearance of meningioma.

We describe a pleomorphic xanthoastrocytoma (PXA) in a young girls whose frontal lobe location, solid structure, dural tail and MRI signal characteristics led to a preoperative diagnosis of meningioma. PXA should be considered in differential diagnosis of tumours affecting young patients with neuroradiological characteristics suggestive of meningioma.

Successful repair of delayed rupture of the left ventricular wall after mitral valve replacement. Report of two cases.

Rupture of left ventricular wall (LVWR) following mitral replacement (MVR) is rare (0.5 to 7.3% of all MVR). Two "types" of LVWR have been recognized and attributed to technical errors during MVR and/or to co-existing unfavourable conditions. The two types are precisely located, and appear "early" during operation, at discontinuation of cardiopulmonary bypass (CPB). Miller et al. have described a "third type" LVWR which depends primarily on local conditions, is located between the other two and occurs "late". Successful repair is rare. The outcome is favourably influenced by intraoperative recognition. This paper reports two LVWRs "type III" which occurred among 282 MVR (0.7%) done in our Department since 1977. Both were successfully repaired respectively 12 (and again 48) and 15 hours after MVRs. To the best of our knowledge these are the only cases of successful repair of a "type III" LVWR reported in the literature. On the basis of this experience some considerations are presented.

[Usefulness of selective partial inversion recover (SPIR) sequences in optic nerve diseases]. / Utilità delle sequenze "Selective Partial Inversion Recover" (SPIR) nelle malattie del nervo ottico.

PURPOSE: To evaluate the yield of SPIR sequences with fat suppression in the diagnosis of optic nerve lesions. MATERIAL AND METHODS: Ten patients with suspected optic nerve involvement on the basis of clinical data and abnormalities of visual evoked potentials were examined. MRI was performed with a 1.5 T unit (Philips NT 15) using T1 weighted conventional spin-echo and T1- and T2 weighted SPIR sequences with fat suppression. Axial images were obtained along the optic nerve course, while coronal images throughout the optic nerve axis; slices were 3 mm thick. Axial T2 weighted SPIR sequences were also performed with the volumetric technique (1.5 mm thickness); coronal and parasagittal reconstructions along the nerve axis were obtained too. After paramagnetic contrast medium injection, conventional T1 weighted and SPIR sequences were performed on axial and coronal planes. RESULTS: Optic nerve lesions consistent with the diagnosis of neuritis were demonstrated with T2 weighted images in 4 of 10 patients. No abnormalities and/or nerve enlargement were found on T1 weighted images. An enhancement area was seen after contrast medium injection in only one case. MRI showed a pilocytic astrocytoma in one patient and selective atrophy of the right optic nerve in another. MRI showed normal findings in 4 patients. CONCLUSIONS: T1 and T2 weighted fat-suppressed SPIR imaging of the optic nerve improves anatomical definition, lesion detection and characterization in optic nerve conditions.

[Assessment with magnetic resonance with Turbo-FLAIR sequences and volumetric analysis of the hippocampal region in drug-resistant temporal epilepsy]. / Valutazione con Risonanza Magnetica con sequenze Turbo-FLAIR e analisi volumetrica della regione ippocampale nell'epilessia temporale farmaco-resistente.

INTRODUCTION: We studied the hippocampal region using Fluid Attenuation Inversion Recovery (Turbo-FLAIR) sequences to detect signal intensity abnormalities, and volumetric sequences to detect cortical thickness changes, in patients with drug-resistant temporal epilepsy. MATERIALS AND METHODS: We examined 30 patients with drug-resistant temporal epilepsy with a 1.5 Tesla unit (NT 15 Philips Gyroscan). Conventional SE, Turbo SE, IR, Turbo-FLAIR, volumetric 3D sequences on coronal plane, PD, T2-weighted SE sequences on axial plane, T1-weighted SE on sagittal plane were performed. Signal intensity and volumetric computerized measurements were obtained using the SUN system. RESULTS: Differences in signal intensity values between the two hippocampal regions were found in 18 patients with Turbo-FLAIR sequences. In 6 of these patients no significant differences in computerized evaluation of signal intensity were detected with either conventional or Turbo-SE sequences. Volumetric analysis showed hippocampal cortex thinning in 9 of 18 patients with hippocampal signal intensity abnormalities. CONCLUSIONS: Turbo-FLAIR were the best sequences for the detection of signal intensity changes in the hippocampal region. Such changes are strongly suggestive of hippocampal sclerosis, especially when associated with cortical atrophy.

Supratentorial glioblastoma: neuroradiological findings and survival after surgery and radiotherapy.

Few studies have attempted to correlate neuroimaging with outcome in patients with glioblastoma. Our aim was to evaluate the relationship between neuroradiological findings and survival in these patients. We studied 18 consecutive patients with glioblastoma who had undergone surgery and radiotherapy. We assessed the following features, using preoperative CT and/or MRI: tumour size, extent of necrotic area within the mass, extent of perifocal oedema and contrast enhancement. The mean survival was 14.2 +/- 5 months (range 6-22). The extent of radiological evidence of necrosis within the mass correlated significantly with survival time, whereas tumour size, perifocal oedema and contrast enhancement did not.

Radiological assessment of necrosis in glioblastoma: variability and prognostic value.

In a previous study, we found that the extent of necrosis was the only radiological feature which correlated significantly with survival in patients with glioblastoma. The aim of this paper was to evaluate the variability and prognostic value of the extent of the necrotic area as seen on contrast-enhanced MRI and CT in a larger series. We studied 72 patients who underwent surgical removal of supratentorial glioblastomas and had CT and/or MRI with contrast medium before surgery; 38, all undergoing the same treatment (surgery plus radiotherapy), were followed clinically. Necrosis within the tumour varied greatly, ranging from none (only 1 case) to involvement of 76% of the tumour. Survival data in the subgroup suggested that only patients with a small area of necrosis (less than 35% of the tumour) had a significantly longer survival time. When necrosis involved more than 35% of the mass, patients had a shorter survival time, without any further correlation with the extent of necrosis.

Relationship between thallium-201 uptake by supratentorial glioblastomas and their morphological characteristics on magnetic resonance imaging.

Single-photon emission tomography (SPET) with thallium-201 is used in the assessment of patients with gliomas because the amount of 201Tl accumulated by the tumoral cells increases in proportion to the degree of tumour malignancy, thus making it possible to differentiate high-grade from low-grade gliomas or recurrences from radiation necrosis. However, in large areas of tissue such as those examined in 201Tl SPET studies, the uptake of 201Tl may vary considerably even in tumours with the same histological diagnosis, as occurs in glioblastomas (GBMs). In order to evaluate the possible influence of the macroscopic characteristics of tumours on 201Tl uptake, we studied a series of 13 patients with histologically proven GBMs, comparing magnetic resonance imaging (MRI) parameters such as tumour dimensions, perilesional oedema, intratumoral necrosis and contrast enhancement with the degree of 201Tl uptake. The patients underwent both 201Tl SPET and MRI before surgery. The 201Tl index (tumour/contralateral unaffected brain) was calculated using two different region of interest (ROI) methods: the first employed irregular large ROIs (3.2+/-13.9 cm2) including pixels with more than 50% maximum activity; the second employed regular square small ROIs (2.7 cm2) centered on the maximum activity of the lesion. Of the MRI morphological parameters studied, only necrosis significantly reduced the degree of 201Tl uptake in GBMs when larger ROIs were used. However, by using small regular ROIs the influence of necrosis on 201Tl uptake was found to be less relevant. Since necrosis is related to tumour proliferative activity and represents a negative prognostic factor in astrocytoma, a possible underestimation of 201Tl uptake due to intratumoral necrosis must be carefully evaluated.