A comparison of MR imaging with fast-FLAIR, HASTE-FLAIR, and EPI-FLAIR sequences in the assessment of patients with multiple sclerosis

BACKGROUND AND PURPOSE: Fast fluid-attenuated inversion-recovery (FLAIR) sequences are sensitive for detecting lesions in patients with multiple sclerosis (MS). More rapid fast-FLAIR imaging of the brain can be achieved by the concomitant use of half-Fourier acquisition single-shot turbo spin-echo (HASTE-FLAIR) and echo-planar imaging (EPI-FLAIR). The present study was performed in a large cohort of subjects to assess and compare the number and volume of brain lesions detected by the fast-FLAIR, HASTE-FLAIR, and EPI-FLAIR sequences in patients with MS. METHODS: Fast-FLAIR, HASTE-FLAIR, and EPI-FLAIR sequences were obtained from 46 consecutive MS patients. Lesions seen on each type of sequence were counted and classified by consensus by two observers. Lesion volumes were measured using a semiautomated segmentation technique based on local thresholding. RESULTS: The quality of the fast-FLAIR images was significantly better than that of HASTE-FLAIR and EPI-FLAIR images. Fast-FLAIR revealed significantly more lesions and higher lesion volumes than did HASTE-FLAIR and EPI-FLAIR. A similar number of large lesions was detected by the three sequences, but HASTE-FLAIR and EPI-FLAIR showed significantly fewer small and intermediate lesions than did fast-FLAIR. The number of lesions seen on HASTE-FLAIR and EPI-FLAIR images was similar. CONCLUSION: HASTE-FLAIR and EPI-FLAIR sequences revealed as many large MS lesions as fast-FLAIR. Because their acquisition times are only a fraction of that needed for fast-FLAIR sequences, they may be useful for making a rapid diagnosis of MS in uncooperative patients. Their reduced ability to detect smaller lesions indicates that they should not be used as a routine approach to imaging patients with MS.     

The use of magnetic resonance imaging in multiple sclerosis treatment trials: power calculations for annual lesion load measurement

Phase III definitive treatment trials of new multiple sclerosis (MS) therapies now routinely incorporate an annual magnetic resonance imaging protocol, with change in T2-weighted brain lesion load providing an important outcome measure. To date the accepted strategy has been to perform a core imaging protocol on all patients in such studies. The aim of this study was to provide power calculations based on this MRI endpoint. Serial MRI data from 128 patients with either relapsing remitting (RR) or secondary progressive (SP) MS were used to calculate sample size requirements using a repeated measures analysis of variance design. We provide sample size calculations based on various follow-up intervals and effect sizes. Sample sizes for the SPMS cohort were substantially larger than for the RRMS group, reflecting the greater variance in lesion load changes between patients in the SPMS group. With a follow-up of 3 years, we estimate that only 12 and 33 patients per arm are needed to show stabilisation of MRI lesion load in the RRMS and SPMS groups, respectively. Our results suggest that ongoing phase III treatment trials are more than adequately powered to detect even subtle treatment effects, and indicate that incorporating measurements from longer follow-up durations increases power substantially. We conclude that an annual imaging protocol provides a robust and powerful tool for assessing effects on the radiological appearance of the disease process. Received: 11 February 1999/Received in revised form: 28 July 1999/Accepted: 10 October 1999     

Visualization of cranial nerves I–XII: value of 3D CISS and T2-weighted FSE sequences

The aim of this study was to evaluate the sensitivity of the three-dimensional constructive interference of steady state (3D CISS) sequence (slice thickness 0.7 mm) and that of the T2-weighted fast spin echo (T2-weighted FSE) sequence (slice thickness 3 mm) for the visualization of all cranial nerves in their cisternal course. Twenty healthy volunteers were examined using the T2-weighted FSE and the 3D CISS sequences. Three observers evaluated independently the cranial nerves NI–NXII in their cisternal course. The rates for successful visualization of each nerve for 3D CISS (and for T2-weighted FSE in parentheses) were as follows: NI, NII, NV, NVII, NVIII 40 of 40 (40 of 40), NIII 40 of 40 (18 of 40), NIV 19 of 40 (3 of 40), NVI 39 of 40 (5 of 40), NIX, X, XI 40 of 40 (29 of 40), and NXII 40 of 40 (4 of 40). Most of the cranial nerves can be reliably assessed when using the 3D CISS and the T2-weighted FSE sequences. Increasing the spatial resolution when using the 3D CISS sequence increases the reliability of the identification of the cranial nerves NIII–NXII. Received: 29 September 1999; Revised: 2 February 2000; Accepted: 21 March 2000     

Ultrahigh verapamil-loaded controlled release polymeric beads using superamphiphobic substrate: D-optimal statistical design,in vitro and in vivo performance

Controlled-release multiparticulate systems of hydrophilic drugs usually suffer from poor encapsulation and rapid-release rate. In the present study, ultra-high loaded controlled release polymeric beads containing verapamil hydrochloride (VP) as hydrophilic model drug were efficiently prepared using superamphiphobic substrates aiming to improve patient compliance by reducing dosing frequency. Superamphiphobic substrates were fabricated using clean aluminum sheets etched with ammonia solution and were treated with 1.5% (w/v) perfluorodecyltriethoxysilane (PFDTS) alcoholic solution. The effect of the main polymer type (lactide/glycolide (PLGA) 5004A, PLGA 5010, and polycaprolactone (PCL)), copolymer (Eudragit RS100) content together with the effect of drug load on encapsulation efficiency (EE%) and in vitro drug release was statistically studied and optimized via D-optimal statistical design. In vivo pharmacokinetic study was carried out to compare the optimized system relative to the market product (Isoptin^®). Results revealed that superamphiphobic substrates were successfully prepared showing a rough micro-sized hierarchical structured surface upon observing with scanning electron microscope and were confirmed by high contact angles of 151.60?±?2.42 and 142.80°±05.23° for water and olive oil, respectively. The fabricated VP-loaded beads showed extremely high encapsulation efficiency exceeding 92.31% w/w. All the prepared systems exhibited a controlled release behavior with Q12?h ranging between 5.46 and 95.90%w/w. The optimized VP-loaded system composed of 150?mg (1.5% w/v) PCL without Eudragit RS100 together with 160?mg VP showed 2.7-folds mean residence time compared to the market product allowing once daily administration instead of three times per day.     

Conventional magnetic resonance imaging in confirmed progressive supranuclear palsy and multiple system atrophy

Conventional magnetic resonance imaging (cMRI) is often used to aid the diagnosis of progressive supranuclear palsy (PSP) and multiple system atrophy (MSA), but its ability to predict the histopathological diagnosis has not been systematically studied. cMRI from 48 neuropathologically confirmed cases, including PSP (n = 22), MSA (n = 13), Parkinson's disease (PD) (n = 7), and corticobasal degeneration (n = 6), and controls (n = 9) were assessed blinded to clinical details and systematically rated for reported abnormalities. Clinical diagnosis and macroscopic postmortem findings were retrospectively assessed. Radiological assessment of MRI was correct in 16 of 22 (72.7%) PSP cases and 10 of 13 (76.9%) MSA cases with substantial interrater agreement (Cohen's kappa 0.708; P < .001); no PSP case was misclassified as MSA or vice versa. MRI was less sensitive but more specific than clinical diagnosis in PSP and both more sensitive and specific than clinical diagnosis in MSA. The “hummingbird” and “morning glory” signs were highly specific for PSP, and “the middle cerebellar peduncle sign” and “hot cross bun” for MSA, but sensitivity was lower (up to 68.4%) and characteristic findings may not be present even at autopsy. cMRI, clinical diagnosis, and macroscopic examination at postmortem have similar sensitivity and specificity in predicting a neuropathological diagnosis. We have validated specific radiological signs in pathologically confirmed PSP and MSA. However, the low sensitivity of these and macroscopic findings at autopsy suggest a need for imaging techniques sensitive to microstructural abnormalities without regional atrophy. © 2012 Movement Disorder Society     

Milestones in magnetic resonance imaging and transcranial sonography of movement disorders

Twenty‐five years ago, when this journal was initiated, imaging of movement disorders was in its infancy. Since that time, magnetic resonance imaging has become a standard technique that is routinely performed in patients with movement disorders in order to exclude secondary causes and in some instances to provide specific information that aids in making the diagnosis of a neurodegenerative condition. Transcranial sonography is a more recent advance and is now widely employed to aid in the diagnosis of Parkinson's disease and possibly in detecting individuals in the premotor phases of the disease. Investigations are currently under way to evaluate the value of this technique in other movement disorders. © 2011 Movement Disorder Society     

Superior oblique myokymia: magnetic resonance imaging support for the neurovascular compression hypothesis

Superior oblique myokymia is a rare movement disorder thought to be caused by vascular compression of the trochlear nerve. Direct display of such neurovascular compression by magnetic resonance imaging has been lacking. The goal of this study was to assess the presence of neurovascular contacts in patients with superior oblique myokymia, using a specific magnetic resonance imaging protocol. A total of 6 patients suffering from right superior oblique myokymia underwent detailed neuro-ophthalmological examination, which showed tonic or phasic eye movement. All patients underwent magnetic resonance imaging, using a magnetic resonance imaging Fourier transform constructive interference in steady-state sequence in combination with magnetic resonance imaging time of flight magnetic resonance arteriography both before and after the administration of Gd-DTPA. With this protocol, the trochlear nerve could be visualized on 11 of 12 sides (92%). Arterial contact was detected at the root exit zone of the symptomatic right trochlear nerve in all 6 patients (100%). No arterial contact was identified at the root exit zone of the asymptomatic left trochlear nerve in any of the 5 left nerves visualized. In conclusion, superior oblique myokymia can result from neurovascular contact at the root exit zone of trochlear nerve, and therefore should be considered among the neurovascular compression syndromes.     

Detailed anatomy of the intracranial segment of the hypoglossal nerve: neurovascular relationships and landmarks on magnetic resonance imaging sequences

OBJECT: The thin hypoglossal nerve can be very difficult to distinguish on magnetic resonance (MR) images. The authors used a combination of sequences to increase the reliability of MR imaging in its demonstration of the 12th cranial nerve as well as to assess the course of the nerve, display its relationships to adjacent vessels, and provide landmarks for evaluating the nerve in daily practice. METHODS: The study group consisted of 34 volunteers (68 nerves) in whom a three-dimensional (3D) Fourier-transformation constructive interference in steady-state (CISS) sequence and a 3D T1-weighted contrast-enhanced magnetization-prepared rapid-acquisition gradient-echo (MPRAGE) sequence were applied. Two trained neuroradiologists collaboratively identified the hypoglossal trigone, preolivary sulcus, 12th cranial nerve, posterior inferior cerebellar artery, vertebral artery, 12th nerve root sleeve, and the hypoglossal canal on each side. The 3D CISS sequence successfully demonstrated the hypoglossal trigone (100% of images), 12th nerve root bundles (100% of images), and 12th nerve sleeves (88.2% of images). The canalicular segment was exhibited with the aid of plain 3D CISS sequences in 74% of images and by using contrast-enhanced 3D CISS sequences and contrast-enhanced MPRAGE sequences in 100% of images. The landmarks that proved useful to identify the cisternal segment of the 12th cranial nerve included the hypoglossal trigone, preolivary sulcus, and 12th nerve root sleeve. Neurovascular contact was identified in 61% of root bundles. The roots were distorted in 44% of these contacts. CONCLUSIONS: The contrast-enhanced 3D CISS sequence consistently displayed the cisternal segment as well as the canalicular segments of the hypoglossal nerve and is, therefore, the best sequence to visualize the complete cranial course of this nerve. Landmarks such as the 12th nerve sleeves can assist in the identification of this nerve.