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PurposeMany MRI sequences are sensitive to motion and its associated artifacts. The linearized geometric solution (LGS), a balanced steady-state free precession (bSSFP) off-resonance signal demodulation technique, is evaluated with respect to motion artifact resilience.Theory and methodsThe mechanism and extent of LGS motion artifact resilience is examined in simulated, flow phantom, and in vivo clinical imaging. Motion artifact correction capabilities are decoupled from susceptibility artifact correction when feasible to permit controlled analysis of motion artifact correction when comparing the LGS with standard and phase-cycle-averaged (complex sum) bSSFP imaging.ResultsSimulations reveal that the LGS demonstrates motion artifact reduction capabilities similar to standard clinical bSSFP imaging techniques, with slightly greater resilience in high SNR regions and for shorter-duration motion. Flow phantom experiments assert that the LGS reduces shorter-duration motion artifact error by ∼24%-65% relative to the complex sum, whereas reconstructions exhibit similar error reduction for constant motion. In vivo analysis demonstrates that in the internal auditory canal/orbits, the LGS was deemed to have less artifact in 24%/49% and similar artifact in 76%/51% of radiological assessments relative to the complex sum, and the LGS had less artifact in 97%/81% and similar artifact in 3%/16% of assessments relative to standard bSSFP. Only 2 of 63 assessments deemed the LGS inferior to either complex sum or standard bSSFP in terms of artifact reduction.ConclusionThe LGS provides sufficient bSSFP motion artifact resilience to permit robust elimination of susceptibility artifacts, inspiring its use in a wide variety of applications.

Background and Purpose: To assess the feasibility of 3‐dimensional stereotactic surface projection (3D‐SSP) as applied to arterial spin labeling (ASL) in a clinical pilot study. Methods: A retrospective sample of 10 consecutive patients who underwent ASL as part of a clinically indicated MR examination was collected during this pilot study. Five additional subjects with normal cerebral perfusion served as a control group. Following voxel‐wise M0‐correction, cerebral blood flow (CBF) quantification, and stereotactic anatomic standardization, voxel‐wise CBF from an individual's ASL dataset was extracted to a set of predefined surface pixels (3D‐SSP). A normal database was created from averaging the extracted CBF datasets of the control group. Patients' datasets were compared individually with the normal database by calculating a Z‐score on a pixel‐by‐pixel basis and were displayed in 3D‐SSP views for visual inspection. Independent, two‐expert reader assessment, using a 3‐point scale, compared standard quantitative CBF images to the 3D‐SSP maps. Results: Patterns and severities of regionally reduced CBF were identified, by both independent readers, in the 3D‐SSP maps. Reader assessment demonstrated preference for 3D‐SSP over traditionally displayed standard quantitative CBF images in three of four evaluated imaging metrics (p =.026,.031, and.013, respectively); 3D‐SSP maps were never found to be inferior to the standard quantitative CBF images. Conclusions: Three‐dimensional SSP maps are feasible in a clinical population and enable quantitative data extraction and localization of perfusion abnormalities by means of stereotactic coordinates in a condensed display. The proposed method is a promising approach for interpreting cerebrovascular pathophysiology. [ABSTRACT FROM AUTHOR]

Objectives. Follow-up with a primary care provider (PCP) is recommended after an emergency department (ED) visit for asthma to assess clinical status and develop a management plan to improve future care. However, previous ED-based studies of urban children with asthma have reported low follow-up rates. The objective of this study was to determine whether scheduling an appointment at the time of an ED visit improves PCP follow-up for urban children. A secondary goal was to assess the effect of this intervention on short-term health outcomes and the use of recommended preventive controller medications. Methods. This randomized trial enrolled a convenience sample of children who were 2 to 18 years old and discharged after treatment for acute asthma in an urban children's hospital ED. Both intervention and control subjects were instructed to follow up with their PCP within 3 to 5 days. Study staff assisted intervention subjects to call their PCP from the ED and schedule an appointment. When follow-up could not be scheduled, assistance continued after ED discharge by telephone until an appointment date was confirmed. Study outcomes included PCP visits, asthma-related morbidity, and daily use of preventive medication 4 weeks after the ED visit. Outcomes were assessed by telephone interview and confirmed by PCP record review. Results. A total of 278 eligible subjects were enrolled over 8 months; intervention and control groups were similar by demographic variables and PCP type as well as by asthma history, symptoms, and previous medication use. Only 38% of subjects reported using a daily controller medication, although 70% described persistent asthma symptoms for which these are recommended. For the intervention group, follow-up appointments were successfully obtained during the ED visit for 24% of subjects; when unsuccessful, a median of 3 telephone calls (range: 1-14) were needed to confirm that an appointment had been scheduled. During the 4 weeks after the ED visit, intervention subjects were more likely than controls to follow up with their PCP (64% vs 46%; relative probability for follow-up: 1.4; 95% confidence interval: 1.1-1.7). Study groups did not differ in return ED visits, missed school or work, or the percentage reporting daily use of a controller medication (58% vs 54%) 4 weeks after the ED visit. The median time to the next PCP visit was shorter among intervention subjects (13 vs 54 days). Conclusions. Scheduling an appointment after an ED visit increased the likelihood that urban children with asthma would follow up with a PCP. An appointment could not be obtained during the ED visit for most children. Other interventions are needed to improve linkage between ED and primary care for asthma and to improve the use of controller medications. Pediatrics 2003;111: 495-502; asthma, emergency, primary care, children., ABBREVIATIONS. NAEPP, National Asthma Education and Prevention Program; PCP, primary care provider; ED, emergency department; CI, confidence interval. Efforts to improve care for childhood asthma have received increasing attention in [...]

Aims: The objective of this study was to compare the diagnostic performance of the baseline pre-contrast images of dynamic susceptibility contrast perfusion-weighted imaging (DSC-PWI) with conventional T2*gradient recalled echo (GRE) imaging for detection of hemorrhage in acute ischemic stroke patients. Material and methods: T2*GRE and DSC-PWI from 393 magnetic resonance imaging scans from 221 patients enrolled in three prospective stroke studies were independently evaluated by two readers blinded to clinical and other imaging data. Agreement between T2*GRE and DSC-PWI for the presence of hemorrhage, and acute hemorrhagic transformation, was assessed using the kappa statistic. Inter-reader agreement was also assessed using the kappa statistic. Results: Agreement between the baseline images of DSC-PWI and T2*GRE regarding the presence of hemorrhage was almost perfect (kreader 1 : 0.90, 95% confidence interval 0.86–0.95 and kreader 2 : 0.91, 95% confidence interval 0.87–0.96). Agreement between the sequences was still higher for detection of acute hemorrhagic transformation (kreader 1 : 0.94, 95% confidence interval 0.91–0.98 and kreader 2 : 0.95, 95% confidence interval 0.92–0.98). Inter-reader agreement for detection of hemorrhage was also almost perfect for both T2*GRE (k: 0.95, 95% confidence interval 0.91–0.98) and DSC-PWI (k: 0.96, 95% confidence interval 0.93–0.99). Acute hemorrhagic transformation detected on T2*GRE was missed on DSC-PWI by one or both readers in 5/393 (1.3%) scans. Conclusion: The almost perfect statistical agreement between DSC-PWI and conventional T2*GRE suggests that DSC-PWI is sufficient for hemorrhage screening prior to thrombolysis in stroke patients. T2*GRE can therefore be omitted when DSC-PWI is included, thereby shortening the acute ischemic stroke magnetic resonance imaging protocol and expediting treatment. Trial registration: ClinicalTrials.gov Identifier: NCT02586415. [ABSTRACT FROM AUTHOR]

Traumatic cerebrovascular injury (CVI) involving the cervical carotid and vertebral arteries is rare but can lead to stroke, hemodynamic compromise, and mortality in the absence of early diagnosis and treatment. The diagnosis of both blunt cerebrovascular injury (BCVI) and penetrating CVI is based on cerebrovascular imaging. The most commonly used screening criteria for BCVI include the expanded Denver criteria and the Memphis criteria, each providing varying thresholds for subsequent imaging. Neck CTA has supplanted catheter-based digital subtraction angiography as the preferred screening modality for CVI in patients with trauma. This AJR Expert Panel Narrative Review describes the current state of CTA-based cervical imaging in trauma. We review the most common screening criteria for BCVI, discuss BCVI grading scales that are based on neck CTA, describe the diagnostic performance of CTA in the context of other imaging modalities and evolving treatment strategies, and provide a practical guide for neck CTA implementation.

Objective: We hypothesized that the apparent diffusion coefficient (ADC) and other MRI features can be used to predict medulloblastoma histologic subtypes, as defined by the World Health Organization (WHO) in WHO Classification of Tumours of the Central Nervous System., Materials and Methods: A retrospective review of pediatric patients with medulloblastoma between 1989 and 2011 identified 38 patients with both pretreatment MRI and original pathology slides. The mean and minimum tumor ADC values and conventional MRI features were compared among medulloblastoma histologic subtypes., Results: The cohort of 38 patients included the following histologic subtypes: 24 classic medulloblastomas, nine large cell (LC) or anaplastic medulloblastomas, four desmoplastic medulloblastomas, and one medulloblastoma with extensive nodularity. The median age at diagnosis was 8 years (range, 1-21 years) and the median follow-up time was 33 months (range, 0-150 months). The mean ADC (× 10(-3) mm(2)/s) was lower in classic medulloblastoma (0.733 ± 0.046 [SD]) than in LC or anaplastic medulloblastoma (0.935 ± 0.127) (Mann-Whitney test, p = 0.004). Similarly, the minimum ADC was lower in classic medulloblastoma (average ± SD, 0.464 ± 0.056) than in LC or anaplastic medulloblastoma (0.630 ± 0.053) (p = 0.004). The MRI finding of focal cysts correlated with the classic and desmoplastic subtypes (Fisher exact test, p = 0.026). Leptomeningeal enhancement positively correlated with the LC or anaplastic medulloblastoma subtype and inversely correlated with the classic medulloblastoma and desmoplastic medulloblastoma subtypes (p = 0.04). Ring enhancement correlated with tumor necrosis (p = 0.022) and with the LC or anaplastic medulloblastoma histologic subtype (p < 0.001)., Conclusion: The LC or anaplastic medulloblastoma subtype was associated with increased ADC and with ring enhancement, the latter of which correlated with tumor necrosis. These features could be considered in the evaluation of high-risk medulloblastoma subtypes.