BLADE Sequences in Transverse T2-weighted MR Imaging of the Cervical Spine. Cut-off for Artefacts?

PURPOSE: The BLADE (PROPELLER) technique reduces artefacts in imaging of the cervical spine in sagittal orientation, but till now failed to do so in axial orientation, because here it increased through plane CSF-flow artefacts, which spoiled the benefit of BLADE artefact reduction "in plane". The aim of this study was to compare a BLADE sequence with optimised measurement parameters in axial orientation to T2-TSE. MATERIALS AND METHODS: Both sequences were compared in 58 patients with 31 discal, 16 bony and 11 spinal cord lesions. Image sharpness, reliability of spinal cord depiction, CSF flow artefacts and lesion detection were evaluated by 3 independent observers. Additionally the observers were asked which sequence they would prefer for diagnostic workup. Statistical evaluations were performed using sign and χ2 test. RESULTS: BLADE was significantly superior concerning image sharpness, spinal cord depiction and overall lesion detection. BLADE was rated better for most pathologies, for bony lesions the differences compared with TSE were statistically significant. Regarding CSF-flow artefacts both sequences showed no difference. All readers preferred BLADE in side by side reading. CONCLUSION: An optimised axial T2 BLADE sequence decreases the problems of increased through plane CSF-flow artefacts in this orientation. By reducing various other artefacts it yields better image quality and has the potential to reduce the number of non-diagnostic examinations especially in uncooperative patients. KEY POINTS: T2 BLADE/PROPELLER sequences proofed to reduce artefacts in sagittal spine imaging. BLADE/PROPELLER improve image quality, but can aggravate CSF flow artefacts in axial orientation. Optimised parameter setting for axial T2 BLADE reduces "through-plane" CSF artefacts aggravation. Optimised axial T2 BLADE reduces non-diagnostic examinations especially in uncooperative patients.

Evaluating post-interventional occlusion grades of cerebral aneurysms with transcranial contrast-enhanced ultrasound (CEUS) using a matrix probe.

PURPOSE: The main goal of cerebral endovascular aneurysm therapy is the complete occlusion of the aneurysm. Along with the development of new aneurysm treatment devices, repeated controls are necessary. We examined whether contrast-enhanced ultrasound can help to monitor aneurysms after endovascular treatment. MATERIALS AND METHODS: We prospectively examined 12 patients after coiling (7 patients) or flow diverter (FD) implantation (5 patients). These patients were examined with transcranial contrast-enhanced ultrasound using a matrix probe (1 - 5 MHz). Doppler sonography, Power Doppler, contrast harmonic imaging (CHI) and Power Doppler sonography (CPD) were included in the examination. Digital subtraction angiography with 3 D reconstructions served as the gold standard. Two radiologists decided in consensus about the degree of aneurysm occlusion separately in CEUS and digital subtraction angiography using a 4-point grading scheme. RESULTS: The degree of occlusion of the 12 aneurysms comparing the two imaging modalities was identical in 10 cases. In two cases CHI and CPD showed a small aneurysm remnant after coiling in the center of the coil pack while in digital subtraction angiography the aneurysms seemed completely occluded. CONCLUSION: The investigation indicates that contrast-enhanced ultrasound is a supportive, noninvasive method for post-interventional controls of intracranial aneurysms due to its ability to display not only macro- but also microvascularization.

BLADE sequences in transverse T2-weighted MR imaging of the cervical spine. Cut-off for Artefacts?

PURPOSE: The BLADE (PROPELLER) technique reduces artefacts in imaging of the cervical spine in sagittal orientation, but till now failed to do so in axial orientation, because here it increased through plane CSF-flow artefacts, which spoiled the benefit of BLADE artefact reduction "in plane". The aim of this study was to compare a BLADE sequence with optimised measurement parameters in axial orientation to T2-TSE. MATERIALS AND METHODS: Both sequences were compared in 58 patients with 31 discal, 16 bony and 11 spinal cord lesions. Image sharpness, reliability of spinal cord depiction, CSF flow artefacts and lesion detection were evaluated by 3 independent observers. Additionally the observers were asked which sequence they would prefer for diagnostic workup. Statistical evaluations were performed using sign and χ2 test. RESULTS: BLADE was significantly superior concerning image sharpness, spinal cord depiction and overall lesion detection. BLADE was rated better for most pathologies, for bony lesions the differences compared with TSE were statistically significant. Regarding CSF-flow artefacts both sequences showed no difference. All readers preferred BLADE in side by side reading. CONCLUSION: An optimised axial T2 BLADE sequence decreases the problems of increased through plane CSF-flow artefacts in this orientation. By reducing various other artefacts it yields better image quality and has the potential to reduce the number of non-diagnostic examinations especially in uncooperative patients.

BLADE sequences in sagittal T2-weighted MR imaging of the cervical spine and spinal cord--lesion detection and clinical value.

PURPOSE: Using the BLADE (PROPELLER) technique for T2-weighted MR imaging of the cervical spine has proven to be a reliable tool for reducing artifacts typically for this region. The aim of this study was to evaluate whether the application of BLADE sequences has an impact on the detection of small or low contrast spinal cord and epidural lesions. MATERIALS AND METHODS: A standard TSE and a BLADE sequence were compared in 33 patients with 46 spinal cord and epidural lesions for T2-weighted sagittal imaging of the cervical spine. Image sharpness, visualization of the dura, reliability of spinal cord depiction as well as lesion contrast were evaluated by two independent readers. Additionally two experienced neuroradiologists selected in consensus the sequence they would prefer for diagnostic purposes. Statistical evaluations were performed using the sign and the χ2 test. RESULTS: BLADE was significantly superior to TSE regarding image sharpness, visualization of the dura and reliability of spinal cord depiction. Regarding lesion contrast there was a positive trend towards the BLADE sequence. In 17 of 46 lesions, BLADE was judged superior to TSE, while TSE was favored in 10 lesions. In consensus reading both neuroradiologists preferred BLADE for overall image quality in 27 of 33 patients and for lesion contrast in 10 and TSE in 14 of the 33 patients, but 3 TSE sequences were rated as non-diagnostic regarding this criterion. CONCLUSION: For the detection of even small and low-contrast spinal cord lesions, BLADE is at least equivalent to TSE, yielding better overall image quality and fewer non-diagnostic images.

A rare case of supraclinoid internal carotid artery (ICA) fenestration in combination with duplication of the middle cerebral artery (MCA) originating from the ICA fenestration and an associated aneurysm.

Fenestrations and duplications of the cervical and intracranial arteries are rare anatomic variants, reported to be associated with aneurysms or other vascular anomalies. We here present a patient with a supraclinoid ICA fenestration in combination with a duplication of the MCA originating from the ICA fenestration and an associated aneurysm.

Genetic assessment of cortical malformations.

Malformations of cortical development comprise a clinically and etiologically heterogeneous group of distinct structural abnormalities of the cerebral cortex, commonly identified during MR imaging of patients with seizure disorders and/or developmental delay. MR imaging is crucial for further classification and together with additional clinical information and family history guiding specific genetic testing, which today is an integral part of the interdisciplinary diagnostic work-up and allows identification of an underlying genetic alteration in a significant subset of patients. Results of genetic testing may provide important prognostic information and subsequently support prospective therapeutic decisions. Furthermore, genetic forms of cortical malformations may be associated with a significantly increased recurrence risk for further siblings or other relatives and require genetic counselling of the family on individual risks and the options of prenatal or even preimplantation genetic diagnosis.

Selective bilateral hippocampal lesions after theophylline-induced status epilepticus causes a permanent amnesic syndrome.

Theophylline is known to increase the risk of epileptic seizures and might have a role in seizure-induced brain damage. We present a 55-year-old man who developed an amnesic syndrome after status epilepticus, caused by accidental theophylline intoxication. Imaging studies revealed acute, selective bilateral hippocampal damage, which corresponded to severe disturbances in bilateral temporal functions on neuropsychological testing. Three months later, the memory deficits persisted, while imaging exhibited bilateral atrophy of the hippocampus. Upon his long-term, 18-month follow-up, the patient demonstrated improvements in his daily living abilities, despite the persistence of bilateral temporal deficits. This report provides evidence that theophylline has the potential to provoke permanent seizure-induced neural damage, presumably via inhibition of adenosine receptors, and especially in vulnerable regions of the brain, such as the hippocampus.

Refining the phenotype of alpha-1a Tubulin (TUBA1A) mutation in patients with classical lissencephaly.

Mutations in the alpha-1a Tubulin (TUBA1A) gene have recently been found to cause cortical malformations resemblant of classical lissencephaly but with a specific combination of features. To date, TUBA1A mutations have been described in five patients and three foetuses. Our aims were to establish how common TUBA1A mutations are in patients with lissencephaly and to contribute to defining the phenotype associated with TUBA1A mutation. We performed mutation analysis in the TUBA1A gene in 46 patients with classical lissencephaly. In 44 of the patients, mutations in the LIS1 and/or DCX genes had previously been excluded; in 2 patients, mutation analysis was only performed in TUBA1A based on magnetic resonance imaging (MRI) findings. We identified three new mutations and one recurrent mutation in five patients with variable patterns of lissencephaly on brain MRI. Four of the five patients had congenital microcephaly, and all had dysgenesis of the corpus callosum and cerebellar hypoplasia, and variable cortical malformations, including subtle subcortical band heterotopia and absence or hypoplasia of the anterior limb of the internal capsule. We estimate the frequency of mutation in TUBA1A gene in patients with classical lissencephaly to be approximately 4%, and although not as common as mutations in the LIS1 or DCX genes, mutation analysis in TUBA1A should be included in the molecular genetic diagnosis of classical lissencephaly, particularly in patients with the combination of features highlighted in this paper.

Transcranial color-coded duplex sonography for detection of distal internal carotid artery stenosis.

BACKGROUND AND PURPOSE: Gradation of high-grade intracranial internal carotid artery (ICA) stenosis poses a challenge to noninvasive neurovascular imaging, which seems critical for angioplasty in the ICA segments C1 and C5. We investigated cutoff values of intracranial ICA stenosis for transcranial color-coded sonography (TCCS) and compared this method with the "gold standard," digital subtraction angiography (DSA). MATERIALS AND METHODS: Forty patients (mean age, 58.9 +/- 13.8 years) with intracranial ICA lesions were prospectively examined by using TCCS and DSA. Two standard TCCS coronal imaging planes were used to evaluate the intracranial ICA. In addition, a control group of 128 volunteers without cerebrovascular disease (mean age, 48.8 +/- 15.9 years) was investigated to establish standard velocity values. RESULTS: DSA confirmed 96 stenoses and 8 occlusions of the intracranial ICA in the study population. In 9% and 7% of cases, stenosis confined to the C1 or C5 segment was >50% and 70%, respectively. Receiver-operating curves demonstrated cutoff values for >70% stenosis in C1 when the peak systolic velocity (PSV) was >200 cm/s (specificity, 100%; sensitivity, 71%) or the C1/submandibular ICA index was >3 (specificity, 93%; sensitivity, 86%). CONCLUSIONS: TCCS is a reliable adjunctive method to detect and quantify significant stenosis of the intracranial ICA. The assessment of the C1/ICA index and peak systolic velocities maximizes the diagnostic accuracy of C1 stenosis to >70% when extracranial ICA stenosis coexists. Further studies need to be performed to compare the diagnostic accuracies of MR angiography and TCCS with that of DSA.

Location and type of mutation in the LIS1 gene do not predict phenotypic severity.

BACKGROUND: Lissencephaly is a neuronal migration disorder leading to absent or reduced gyration and a broadened but poorly organized cortex. The most common form of lissencephaly is isolated, referred as classic or type 1 lissencephaly. Type 1 lissencephaly is mostly associated with a heterozygous deletion of the entire LIS1 gene, whereas intragenic heterozygous LIS1 mutations or hemizygous DCX mutations in males are less common. METHODS: Eighteen unrelated patients with type 1 lissencephaly were clinically and genetically assessed. In addition, patients with subcortical band heterotopia (n = 1) or lissencephaly with cerebellar hypoplasia (n = 2) were included. RESULTS: Fourteen new and seven previously described LIS1 mutations were identified. We observed nine truncating mutations (nonsense, n = 2; frameshift, n = 7), six splice site mutations, five missense mutations, and one in-frame deletion. Somatic mosaicism was assumed in three patients with partial subcortical band heterotopia in the occipital-parietal lobes or mild pachygyria. We report three mutations in exon 11, including a frameshift which extends the LIS1 protein, leading to type 1 lissencephaly and illustrating the functional importance of the WD domains at the C terminus. Furthermore, we present two patients with novel LIS1 mutations in exon 10 associated with lissencephaly with cerebellar hypoplasia type a. CONCLUSION: In contrast to previous reports, our data suggest that neither type nor position of intragenic mutations in the LIS1 gene allows an unambiguous prediction of the phenotypic severity. Furthermore, patients presenting with mild cerebral malformations such as subcortical band heterotopia or cerebellar hypoplasia should be considered for genetic analysis of the LIS1 gene.

Striatal grey matter increase in patients suffering from fibromyalgia--a voxel-based morphometry study.

Fibromyalgia (FM), among other chronic pain syndromes, such as chronic tension type headache and atypical face pain, is classified as a so-called dysfunctional pain syndrome. Patients with fibromyalgia suffer from widespread, "deep" muscle pain and often report concomitant depressive episodes, fatigue and cognitive deficits. Clear evidence for structural abnormalities within the muscles or soft tissue of fibromyalgia patients is lacking. There is growing evidence that clinical pain in fibromyalgia has to be understood in terms of pathological activity of central structures involved in nociception. We applied MR-imaging and voxel-based morphometry, to determine whether fibromyalgia is associated with altered local brain morphology. We investigated 20 patients with the diagnosis of primary fibromyalgia and 22 healthy controls. VBM revealed a conspicuous pattern of altered brain morphology in the right superior temporal gyrus (decrease in grey matter), the left posterior thalamus (decrease in grey matter), in the left orbitofrontal cortex (increase in grey matter), left cerebellum (increase in grey matter) and in the striatum bilaterally (increase in grey matter). Our data suggest that fibromyalgia is associated with structural changes in the CNS of patients suffering from this chronic pain disorder. They might reflect either a consequence of chronic nociceptive input or they might be causative to the pathogenesis of fibromyalgia. The affected areas are known to be both, part of the somatosensory system and part of the motor system.

Impaired working-memory after cerebellar infarcts paralleled by changes in BOLD signal of a cortico-cerebellar circuit.

A considerable body of evidence supports the notion that cerebellar lesions lead to neuropsychological deficits, including impairments in working-memory, executive tasks and verbal fluency. Studies employing functional magnetic resonance imaging (fMRI) and anatomical tracing in primates provide evidence for a cortico-cerebellar circuitry as the functional substrate of working-memory. The present fMRI study explores the activation pattern during an n-back working-memory task in patients with an isolated cerebellar infarct. To determine each patient's cognitive impairment, neuropsychological tests of working-memory and attention were carried out. We conducted fMRI in nine patients and nine healthy age-matched controls while they performed a 2-back task in a blocked-design. In both groups we found bilateral activations in a widespread cortico-cerebellar network, consisting of the ventrolateral prefrontal cortex (BA 44, 45), dorsolateral prefrontal cortex (BA 9, 46), parietal cortex (BA 7, 40), pre-supplementary motor area (BA 6) anterior cingulate (BA 32). Relative to healthy controls, patients with isolated cerebellar infarcts demonstrated significantly more pronounced BOLD-activations in the precuneus and the angular gyrus during the 2-back task. The significant increase in activation in the posterior parietal areas of the cerebellar patients could be attributed to a compensatory recruitment to maintain task performance. We conclude that cerebellar lesions affect remote cortical regions that are part of a putative cortico-cerebellar network.

Differences in cortical activation during smooth pursuit and saccadic eye movements following cerebellar lesions.

Current evidence supports the proposal that the cerebellum mediates the activity of other brain areas involved in the control of eye movements. Most of the evidence so far has concentrated on the vermis and flocculi as the cerebellar agents of oculomotor control. But there is also evidence for an involvement of the cerebellar hemispheres in eye movement control. Straube et al. (Ann Neurol 42:891-898, 1997) showed that lateral hemispheric lesions affect initiation of smooth pursuit (SPEM) and saccadic eye movements. Ron and Robinson (J Neurophysiol 36:1004-1022, 1973) evoked smooth pursuit and saccadic eye movements by electrical stimulation of crus I and II, as well as in the dentate nuclei of the monkey. Functional MRI studies also provide evidence that the cerebellar hemispheres play a significant role in SPEM and saccadic eye movements. To clarify the role of the cerebral hemispheres in eye movement control we compared the eye movement related blood oxygen level dependent (BOLD) responses of 12 patients with cerebellar lesions due to stroke with those of an aged-matched healthy control group. Six patients showed oculomotor abnormalities such as dysmetric saccades or saccadic SPEM during the experiment. The paradigm consisted of alternating blocks of fixation, visually guided saccades and visually guided SPEM. A nonparametric random-effects group analysis showed a degraded pattern of activation in the patient group during the performance of SPEM and saccadic eye movements in posterior parietal areas putatively containing the parietal eye fields.

In vivo high-resolution MR imaging of neuropathologic changes in the injured rat spinal cord.

BACKGROUND AND PURPOSE: MR imaging is the most comprehensive noninvasive means to assess structural changes in injured central nervous system (CNS) tissue in humans over time. The few published in vivo MR imaging studies of spinal cord injury in rodent models by using field strengths < or = 7T suffer from low spatial resolution, flow, and motion artifacts. The aim of this study was to assess the capacity of a 17.6T imaging system to detect pathologic changes occurring in a rat spinal cord contusion injury model ex vivo and in vivo. METHODS: Seven adult female Fischer 344 rats received contusion injuries at thoracic level T10, which caused severe and reproducible lesions of the injured spinal cord parenchyma. Two to 58 days postinjury, high-resolution MR imaging was performed ex vivo (2) or in vivo in anesthetized rats (5 spinal cord injured + one intact control animal) by using 2D multisection spin- and gradient-echo imaging sequences, respectively, combined with electrocardiogram triggering and respiratory gating. RESULTS: The acquired images provided excellent resolution and gray/white matter differentiation without significant artifacts. Signal intensity changes, which were detected with ex vivo and in vivo MR imaging following spinal cord injury, could be correlated with histologically defined structural changes such as edema, fibroglial scar, and hemorrhage. CONCLUSIONS: These results demonstrate that MR imaging at 17.6T allows high-resolution structural analysis of spinal cord pathology after injury.

Calcified neurocysticercosis lesions trigger symptomatic inflammation during antiparasitic therapy.

We report a patient with neurocysticercosis who developed numerous cerebral edematous lesions while undergoing cysticidal therapy. These lesions outnumbered viable cystic lesions seen before therapy. Most new lesions were subsequently found to be associated with former calcifications not seen on initial MR imaging. Calcified neurocysticercosis lesions can trigger inflammatory reactions during therapy, and the number and location of calcified neurocysticercosis lesions may influence treatment decisions.

[Multiple ischemic vertebrobasilar lesions in temporal arteritis]. / Multiple Ischämien im vertebrobasilären Stromgebiet bei Arteriitis temporalis.

We report a 73-year-old patient with giant cell arteritis who presented with right arm paresis and dysarthria. Vasculitis of the vertebral arteries induced multiple ischemic cerebral lesions in the vertebrobasilar territory, ultimately leading to death despite intensive immunosuppressive therapy. This case illustrates that prompt relief from symptoms of giant cell arteritis upon steroid treatment does not correspond to a remission of the vasculitic process itself. Clinicians should therefore be aware of the possible occult involvement of the vertebral or other major arteries.

Diffusion-weighted imaging with calculated apparent diffusion coefficient in intracranial hemorrhagic lesions.

In the literature published so far, measurement of values of the apparent diffusion coefficient (ADC) using an echo-planar imaging (EPI) technique in intracranial hemorrhagic lesions show no uniform results. Furthermore, no data exist for bleedings into intracranial lesions. We investigated the ADCs of 18 intracranial hemorrhagic lesions of different stages using echo-planar diffusion-weighted imaging (DWI). The ADC values measured in the hemorrhagic lesions ranged from 1.42 x 10(-3) to 0.22 x 10(-3) mm(2)/s. There were no significant differences between the ADC values in the hemorrhagic lesions and the contralateral white matter (P=.39). A differentiation between the lesions only with the ADC value was not possible as well. Using EPI DWI in intracranial hemorrhagic lesions of different stages, no reliable ADC values were found and a dependable differentiation between the lesions is not possible.