Quick-brain magnetic resonance imaging for nonhydrocephalus indications.
ABSTRACT In 2002, "quick-brain" (QB) MR imaging (ultrafast spin echo T2-weighted imaging) was introduced as an alternative technique to CT scanning for assessing children with hydrocephalus. The authors have observed high patient and physician satisfaction with this technique at their institution, which has led to an increasing frequency of its use for nonhydrocephalic indications. The goal in this study was to characterize, quantitate, and assess the use of QB MR imaging for these additional indications.
Between February 2003 and December 2007, 1146 consecutive QB MR imaging studies were performed, and the findings were entered prospectively into a radiology database. All available clinical records were retrospectively reviewed to assign > or = 1 of the following indications to each study: hydrocephalus, macrocephaly, Chiari malformation, intracranial cyst, screening prior to lumbar puncture, screening for congenital anomalies, trauma, and other. Changes in the distribution of indications over time and clinical experience for each indication were reviewed.
The total number of QB imaging studies performed increased each year. The proportion of studies performed for nonhydrocephalic indications also increased (from 23 to 50%). The most common indication was screening for macrocephaly, and all other indications were nearly evenly distributed. Quick-brain MR imaging was used extensively for the initial evaluation and follow-up in patients with little need for additional studies. Its false-negative rate, however, remains unknown.
The role of QB MR imaging for nonhydrocephalic indications is expanding, and it appears promising for a number of screening and surveillance paradigms. "Quick-brain plus" protocols for specific indications may add sensitivity and are under development.
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ABSTRACT: Shunted hydrocephalus in children is a commonly seen diagnosis in hospitals throughout the world, and is one of the most common chronic pediatric neurosurgical conditions. These children undergo numerous studies for routine surveillance as well as for evaluation of shunt malfunction, many of which are associated with significant radiation exposure over the child’s lifetime. It is in the child’s best interest to minimize the overall exposure to ionizing radiation to decrease the chance of the deleterious effects from occurring. The article outlines the epidemiology of ventricular shunt catheters, typical indications and methods for shunt evaluation, and preferred alternative imaging methods that eliminate or reduce radiation exposure.Seminars in Ultrasound CT and MRI 08/2014; DOI:10.1053/j.sult.2014.05.002 · 1.08 Impact Factor
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ABSTRACT: Object Growing concern about potential adverse effects of ionizing radiation exposure during imaging studies is particularly relevant to the pediatric population. To decrease radiation exposure, many institutions use rapid-sequence (or quick-brain) MRI to evaluate cerebral ventricle size. There are obstacles, however, to widespread implementation of this imaging modality. The purpose of this study was to define and quantify these obstacles to positively affect institutional and governmental policy. Methods A 9-question survey was emailed to pediatric neurosurgeons who were either members or candidate members of the American Society of Pediatric Neurosurgeons at every one of 101 institutions in the US and Canada having such a neurosurgeon on staff. Responses were compiled and descriptive statistics were performed. Results Fifty-six institutions completed the survey. Forty-four (79%) of the 56 institutions currently have a rapid-sequence MRI protocol to evaluate ventricle size, while 36 (64%) use it routinely. Of the 44 institutions with a rapid-sequence MRI protocol, 29 (66%) have had a rapid-sequence MRI protocol for less than 5 years while 39 (89%) have had a rapid-sequence MRI protocol for no more than 10 years. Thirty-six (88%) of 41 rapid-sequence MRI users responding to this question obtain a T2-weighted rapid-sequence MRI while 13 (32%) obtain a T1-weighted rapid-sequence MRI. Twenty-eight (64%) of 44 institutions never use sedation while an additional 12 (27%) rarely use sedation to obtain a rapid-sequence MRI (less than 5% of studies). Of the institutions with an established rapid-sequence MRI protocol, obstacles to routine use include lack of emergency access to MRI facilities in 18 (41%), lack of staffing of MRI facilities in 12 (27%), and the inability to reimburse a rapid-sequence MRI protocol in 6 (14%). In the 12 institutions without rapid-sequence MRI, obstacles to implementation include lack of emergency access to MRI facilities in 8 (67%), lack of staffing of MRI facilities in 7 (58%), the inability to reimburse in 3 (25%), and lack of administrative support in 3 (25%). To evaluate pediatric head trauma, 53 (96%) of 55 institutions responding to this question use noncontrast CT, no institution uses rapid-sequence MRI, and only 2 (4%) use standard MRI. Conclusions Many North American institutions have a rapid-sequence MRI protocol to evaluate ventricle size, with most developing this technique within the past 5 years. Most institutions never use sedation, and most obtain T2-weighted sequences. The greatest obstacles to the routine use of rapid-sequence MRI in institutions with and in those without a rapid-sequence MRI protocol are the lack of emergency access and staffing of the MRI facility during nights and weekends.Journal of Neurosurgery Pediatrics 04/2014; 13(6). DOI:10.3171/2014.2.PEDS13567 · 1.37 Impact Factor
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ABSTRACT: Object Surveillance imaging of the cerebral ventricles can be valuable in following up children with shunt-treated hydrocephalus. There also, however, has been recent increased awareness and concern over the potential risk associated with imaging-related radiation exposure in children. Magnetic resonance imaging represents an imaging alternative that does not use ionizing radiation; however, its practical utility has been limited due to the near-uniform requirement for sedation or general anesthesia in children. Magnetic resonance imaging without sedation is often futile because of the movement artifact produced by the nonsedated pediatric patient. Some studies have demonstrated the feasibility of using fast-sequence MRI (fsMRI), but the reported experiences are limited. The authors have incorporated fsMRI into their routine shunt surveillance imaging paradigms and report here a 5-year experience with this modality. Methods The authors initially started using fsMRI for routine surveillance in a single clinic in 2008 and have gradually increased their institutional utilization of this modality as experience has accumulated and protocols have been refined. Imaging sequences obtained for each child include an axial T2-weighted half-Fourier acquisition single-shot turbo spin-echo (HASTE), coronal T2-weighted HASTE, and sagittal T2-weighted HASTE images. The authors conducted a retrospective chart and imaging review. They rated each fsMR image according to 5 visibility parameters: 1) ventricle size, 2) ventricle configuration, 3) presence or absence of transependymal flow, 4) presence or absence of motion artifact, and 5) visualization of the ventricular catheter. Each parameter was graded as 1 (present) or 0 (absent). Thus, the maximum value assigned to each scan could be 5 and the minimum value assigned to each scan could be 0. Interrater reliability between pairs of observers was calculated using the Kendall's tau-b and intraclass coefficients. Results Two hundred patients underwent fsMRI. No child required sedation. The average duration of examinations was approximately 3.37 minutes, and mean age of the patients was 5.7 years. Clinically useful images were attained in all cases. Overall quality of the fsMRI studies based on the 5 different visibility parameters showed that 169 images (84.5%) included 4 or 5 parameters (score ≥ 4) and had statistically significant excellent quality. The Kendall's tau-b for the overall fsMRI ratings was 0.82 (p = 0.002) and the intraclass coefficient was 0.87 (p < 0.0001). Conclusions In the present cohort of 200 patients, fsMRI studies were shown to have an excellent overall quality and a statistically significant high degree of interrater reliability. Consequently, the authors propose that fsMRI is a sufficiently effective modality that eliminates the need for sedation and the use of ionizing radiation and that it should supplant CT for routine surveillance imaging in hydrocephalic patients.Journal of Neurosurgery Pediatrics 02/2014; DOI:10.3171/2014.1.PEDS13447 · 1.37 Impact Factor