Diagnostic Performance of Ultrafast Brain MRI for Evaluation of Abusive Head Trauma

Navigating the Challenges of Delayed Subdural Hemorrhage and COVID-19: A Case Report

The delayed onset of posttraumatic subdural hemorrhage (SDH) represents non-specific clinical features, complicating the diagnostic process, especially in individuals predisposed due to pre-existing risk factors and comorbidities. This case report delineates the medical trajectory of a 61-year-old female patient who sustained a traumatic fall, initially displaying neither clinical nor radiological signs indicative of hemorrhage. However, three weeks post-injury, she developed altered mental status, cephalgia, and emesis. Diagnostic imaging unveiled a significant bilateral acute-on-chronic subdural hemorrhage exerting pronounced mass effect and leading to obliteration of the basal cisterns. Complicating her clinical picture was a concurrent SARS-CoV-2 infection and a medical history of hypertension. Emergent neurosurgical intervention was undertaken, encompassing the creation of bilateral burr holes for drainage and the placement of subdural drains. The patient was managed with the requisite medical therapies. Post-operatively, the patient regained consciousness and exhibited significant neurological improvement. Follow-up imaging demonstrated complete resolution of the subdural hemorrhage, and the patient achieved a full recovery of cognitive function. This case underscores the critical necessity for vigilant surveillance for delayed SDH in patients lacking initial radiographic findings and advocates for individualized therapeutic approaches in patients with concurrent pathologies. Prompt recognition, timely neurosurgical management, and care are pivotal to optimizing outcomes in delayed posttraumatic SDH cases.

Focused Abbreviated Survey MRI Protocols for Brain and Spine Imaging

There has been extensive growth in both the technical development and the clinical applications of MRI, establishing this modality as one of the most powerful diagnostic imaging tools. However, long examination and image interpretation times still limit the application of MRI, especially in emergent clinical settings. Rapid and abbreviated MRI protocols have been developed as alternatives to standard MRI, with reduced imaging times, and in some cases limited numbers of sequences, to more efficiently answer specific clinical questions. A group of rapid MRI protocols used at the authors' institution, referred to as FAST (focused abbreviated survey techniques), are designed to include or exclude emergent or urgent conditions or screen for specific entities. These FAST protocols provide adequate diagnostic image quality with use of accelerated approaches to produce imaging studies faster than traditional methods. FAST protocols have become critical diagnostic screening tools at the authors' institution, allowing confident and efficient confirmation or exclusion of actionable findings. The techniques commonly used to reduce imaging times, the imaging protocols used at the authors' institution, and future directions in FAST imaging are reviewed to provide a practical and comprehensive overview of FAST MRI for practicing neuroradiologists. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

International Consensus Statement on the Radiological Screening of Contact Children in the Context of Suspected Child Physical Abuse

Importance

Physical abuse is a common but preventable cause of long-term childhood morbidity and mortality. Despite the strong association between abuse in an index child and abuse in contact children, there is no guidance outlining how to screen the latter, significantly more vulnerable group, for abusive injuries. Consequently, the radiological assessment of contact children is often omitted, or variably performed, allowing occult injuries to go undetected and increasing the risk of further abuse.

Objective

To report an evidence-based and consensus-derived set of best practices for the radiological screening of contact children in the context of suspected child physical abuse.

Evidence Review

This consensus statement is supported by a systematic review of the literature and the clinical opinion of an internationally recognized group of 26 experts. The modified Delphi consensus process comprised 3 meetings of the International Consensus Group on Contact Screening in Suspected Child Physical Abuse held between February and June 2021.

Findings

Contacts are defined as the asymptomatic siblings, cohabiting children, or children under the same care as an index child with suspected child physical abuse. All contact children should undergo a thorough physical examination and a history elicited prior to imaging. Contact children younger than 12 months should have neuroimaging, the preferred modality for which is magnetic resonance imaging, and skeletal survey. Contact children aged 12 to 24 months should undergo skeletal survey. No routine imaging is indicated in asymptomatic children older than 24 months. Follow-up skeletal survey with limited views should be performed if abnormal or equivocal at presentation. Contacts with positive findings should be investigated as an index child.

Conclusions and Relevance

This Special Communication reports consensus recommendations for the radiological screening of contact children in the context of suspected child physical abuse, establishing a recognized baseline for the stringent evaluation of these at-risk children and providing clinicians with a more resilient platform from which to advocate for them.

Conventional MR Imaging in Trauma Management in Pediatrics

Traumatic brain injury (TBI) is a major cause of death and disability in children across the world. The aim of initial brain trauma management of pediatric patients is to diagnose the extent of TBI and to determine if immediate neurosurgical intervention is required. A noncontrast computed tomography is the recommended diagnostic imaging choice for all patients with acute moderate to severe TBI. This article outlines the current use of conventional MR imaging in the management of pediatric head trauma and discusses potential future recommendations.

Middle meningeal artery embolization in pediatric patient

PURPOSE

There is paucity of data in management of recurrent and expanding subdural hematomas (SDH) within the pediatric population, who are otherwise not surgical candidates. Middle meningeal artery (MMA) embolization has been utilized minimally in this population and here, we explore the utility of this procedure in a 15-month-old-child, along with review of the literature.

METHODS

A case report of a 15-month-old child who underwent MMA embolization for recurrent and expanding SDH in the setting of anticoagulation for cardiac condition. A literature review of MMA embolization in pediatric patients was conducted.

RESULTS

Initially stabilization of SDH was noted on serial imaging; however, recurrent hemorrhages were noted with subsequent boluses of antiplatelet and anticoagulating agents. There are only 5 total reported cases, included ours, of MMA embolization in pediatrics with an overall success rate of 80%.

CONCLUSION

Treatment of chronic or recurrent subdural hematoma by MMA embolization in the pediatric population is understudied. Our case notes limitation of this procedure and impact on long-term success, specifically in patients with systemic illness and ongoing anticoagulation.

Emerging Techniques and Future Directions: Fast and Portable Magnetic Resonance Imaging

Fast MRI and portable MRI are emerging as promising technologies to improve the speed, efficiency, and availability of MR imaging. Fast MRI methods are increasingly being adopted to create screening protocols for the diagnosis and management of acute pathology in the emergency department. Faster imaging can facilitate timely diagnosis, reduce motion artifacts, and improve departmental MR operations. Point-of-care and portable MRI are emerging technologies that require radiologists to reenvision the role of MRI as a tool with greater accessibility, fewer siting constraints, and the ability to provide valuable diagnostic information at the bedside. Recently introduced commercially available pulse sequences and new MRI scanners are bringing these technologies closer to the patient's clinical setting, and we expect their use to only increase over the coming decade. This article provides an overview of these emerging technologies for emergency radiologists.

Parenchymal Insults in Abuse—A Potential Key to Diagnosis

Subdural hemorrhage is a key imaging finding in cases of abusive head trauma and one that many radiologists and radiology trainees become familiar with during their years of training. Although it may prove to be a marker of trauma in a young child or infant that presents without a history of injury, the parenchymal insults in these young patients more often lead to the debilitating and sometimes devastating outcomes observed in this young population. It is important to recognize these patterns of parenchymal injuries and how they may differ from the imaging findings in other cases of traumatic injury in young children. In addition, these parenchymal insults may serve as another significant, distinguishing feature when making the medical diagnosis of abusive head injury while still considering alternative diagnoses, including accidental injury. Therefore, as radiologists, we must strive to look beyond the potential cranial injury or subdural hemorrhage for the sometimes more subtle but significant parenchymal insults in abuse.

NeuroMix-A single-scan brain exam

PURPOSE

Implement a fast, motion-robust pulse sequence that acquires T₁ -weighted, T₂ -weighted, T₂ ^* -weighted, T₂ fluid-attenuated inversion recovery, and DWI data in one run with only one prescription and one prescan.

METHODS

A software framework was developed that configures and runs several sequences in one main sequence. Based on that framework, the NeuroMix sequence was implemented, containing motion robust single-shot sequences using EPI and fast spin echo (FSE) readouts (without EPI distortions). Optional multi-shot sequences that provide better contrast, higher resolution, or isotropic resolution could also be run within the NeuroMix sequence. An optimized acquisition order was implemented that minimizes times where no data is acquired.

RESULTS

NeuroMix is customizable and takes between 1:20 and 4 min for a full brain scan. A comparison with the predecessor EPIMix revealed significant improvements for T₂ -weighted and T₂ fluid-attenuated inversion recovery, while taking only 8 s longer for a similar configuration. The optional contrasts were less motion robust but offered a significant increase in quality, detail, and contrast. Initial clinical scans on 1 pediatric and 1 adult patient showed encouraging image quality.

CONCLUSION

The single-shot FSE readouts for T₂ -weighted and T₂ fluid-attenuated inversion recovery and the optional multishot FSE and 3D-EPI contrasts significantly increased diagnostic value compared with EPIMix, allowing NeuroMix to be considered as a standalone brain MRI application.

Decreased Need for Anesthesia during Ultra-Fast Cranial MRI in Young Children: One-Year Summary

PURPOSE

 Rapid volume coverage sequences based on real-time MRI allow for scanning of the entire brain within a few seconds. Movements of children become almost irrelevant due to the ultra-fast acquisition of 30 ms per slice. The adoption of these sequences in a real-time cranial MRI protocol (RT-cMRI) is expected to reduce the frequency of examinations requiring anesthesia in infants and toddlers. The aim of the study was to quantify the reduction in the number of anesthesia examinations in young children after the implementation of the new RT-cMRI protocol.

MATERIALS AND METHODS

 All cMRI studies of children up to 6 years in the first 12 months after the establishment of the RT-cMRI 2019/2020 were retrospectively compared to a matched group of the same period in 2017/2018. The frequency of examinations under anesthesia vs. non-sedation examinations was analyzed. In addition, the number of follow-up examinations and the effectiveness of RT-cMRI was determined.

RESULTS

 The launch of RT-cMRI led to a significant decrease in the proportion of cMRI under anesthesia from 92 % to 55 %. Only 2 % of the RT-cMRI failed and required conventional MRI under sedation in the follow-up. The speed and ease of use of RT-cMRI increased the number of follow-up examinations from 1.3 to 1.4 examinations per child.

CONCLUSION

 This innovative real-time MRI examination allows a drastic reduction in the number of studies under anesthesia for suitable cranial pathologies in children under 6 years. However, cautious selection of indications as well as adjustments to the workflow in the radiological department are required.

KEY POINTS

  · Real-time MRI sequences are almost unaffected by patient movement. · The application of real-time cranial MRI can spare children from sedation. · Low-threshold access results in more frequent follow-up examinations.

CITATION FORMAT

· Sorge I, Hirsch FW, Voit D et al. Decreased Need for Anesthesia during Ultra-Fast Cranial MRI in Young Children: One-Year Summary. Fortschr Röntgenstr 2021; DOI: 10.1055/a-1561-2430.

Rapid-sequence MRI for evaluation of pediatric traumatic brain injury: a systematic review

OBJECTIVE

Rapid-sequence MRI (RSMRI) of the brain is a limited-sequence MRI protocol that eliminates ionizing radiation exposure and reduces imaging time. This systematic review sought to examine studies of clinical RSMRI use for pediatric traumatic brain injury (TBI) and to evaluate various RSMRI protocols used, including their reported accuracy as well as clinical and systems-based limitations to implementation.

METHODS

PubMed, EMBASE, and Web of Science databases were searched, and clinical articles reporting the use of a limited brain MRI protocol in the setting of pediatric head trauma were identified.

RESULTS

Of the 1639 articles initially identified and reviewed, 13 studies were included. An additional article that was in press at the time was provided by its authors. The average RSMRI study completion time was variable, spanning from 1 minute to 16 minutes. RSMRI with "blood-sensitive" sequences was more sensitive for detection of hemorrhage compared with head CT (HCT), but less sensitive for detection of skull fractures. Compared with standard MRI, RSMRI had decreased sensitivity for all evidence of trauma.

CONCLUSIONS

Protocols and uses of RSMRI for pediatric TBI were variable among the included studies. While traumatic pathology missed by RSMRI, such as small hemorrhages and linear, nondisplaced skull fractures, was frequently described as clinically insignificant, in some cases these findings may be prognostically and/or forensically significant. Institutions should integrate RSMRI into pediatric TBI management judiciously, relying on clinical context and institutional capabilities.

Utility of a pediatric fast magnetic resonance imaging protocol as surveillance scanning for traumatic brain injury

OBJECTIVE

Traumatic brain injury (TBI) is a prevalent pediatric pathology in the modern emergency department. Computed tomography (CT) is utilized for detection of TBI and can result in cumulatively high radiation exposure. Recently, a fast brain magnetic resonance imaging (fbMRI) protocol has been employed for rapid imaging of hydrocephalus in pediatric patients. The authors investigate the utility of a modified trauma-focused fbMRI (t-fbMRI) protocol as an alternative to surveillance CT in the setting of acute TBI in pediatric patients, thus reducing radiation exposure while improving diagnostic yield.

METHODS

A retrospective review was performed at the authors' institution for all pediatric patients who had undergone t-fbMRI within 72 hours of an initial CT scan, using a 1.5- or 3-T MR scanner for trauma indications. Forty patients met the study inclusion criteria. The authors performed a comparison of findings on the reads of CT and fbMRI, and a board-certified neuroradiologist conducted an independent review of both modalities.

RESULTS

T-fbMRI outperformed CT in specificity, sensitivity, and negative predictive value for all injury pathologies measured, except for skull fractures. T-fbMRI demonstrated a sensitivity of 100% in the detection of extraaxial bleed, intraventricular hemorrhage, and subarachnoid hemorrhage and had a sensitivity of 78% or greater for epidural hematoma, subdural hematoma, and intraparenchymal hemorrhage. T-fbMRI yielded a specificity of 100% for all types of intracranial hemorrhages, with a corresponding negative predictive value that exceeded that for CT.

CONCLUSIONS

In pediatric populations, the t-fbMRI protocol provides a valid alternative to CT in the surveillance of TBI and intracranial hemorrhage. Although not as sensitive in the detection of isolated skull fractures, t-fbMRI can be used to monitor pathologies implicated in TBI patients while minimizing radiation exposure from traditional surveillance imaging.

Magnetic Resonance Imaging of the Brain in the Pediatric Emergency Department

Emergent imaging of the brain is often required to diagnose and manage serious and life-threatening conditions for children presenting to the emergency department. In an effort to reduce children's exposure to ionizing radiation, the use of magnetic resonance imaging (MRI) as an alternative to computed tomography (CT) is increasing. In some conditions, an urgent MRI rather than CT is critical for making management decisions. The purpose of this review is to highlight 3 emergency medical conditions-acute stroke, traumatic brain injury, and hydrocephalus-in which timely MRI of the brain is required for diagnosis and management. Another aim will be to guide providers in determining when and what limited MRI sequences of the brain can be used in lieu of CT in these emergency medical conditions.

Identification of Abusive Head Trauma in High-Risk Infants: A Cost-Effectiveness Analysis

OBJECTIVES

To evaluate the cost-effectiveness of abusive head trauma detection strategies in emergency department settings with and without rapid magnetic resonance imaging (rMRI) availability.

STUDY DESIGN

A Markov decision model estimated outcomes in well-appearing infants with high-risk chief complaints. In an emergency department without rMRI, we considered 3 strategies: clinical judgment, universal head computed tomography (CT) scan, or the Pittsburgh Infant Brain Injury Score (PIBIS) with a CT scan. In an emergency department with rMRI for brain availability, we considered additional strategies: universal rMRI, universal rMRI with a CT scan, PIBIS with rMRI, and PIBIS with rMRI followed by a CT scan. Correct diagnosis eliminated future risk; missed abusive head trauma led to reinjury risk with associated poor outcomes. Cohorts were followed for 1 year from a healthcare perspective. One-way and probabilistic sensitivity analyses were performed. The main outcomes evaluated in this study were abusive head trauma correctly identified and incremental cost per quality-adjusted life-year.

RESULTS

Without rMRI availability, PIBIS followed by a CT scan was the most cost-effective strategy. Results were sensitive to variation of CT scan-induced cancer parameters and abusive head trauma prevalence. When rMRI was available, universal rMRI followed by a confirmatory CT scan cost $25 791 to gain 1 additional quality-adjusted life-year compared with PIBIS followed by rMRI with a confirmatory CT scan. In both models, clinical judgement was less effective than alternative strategies.

CONCLUSIONS

By applying CT scans to a more targeted population, PIBIS decreases radiation exposure and is more effective for the identification of abusive head trauma compared with clinical judgment. When rMRI is available, universal rMRI with a CT scan is more effective than PIBIS and is economically favorable.

Ultrafast Brain Magnetic Resonance Imaging in Acute Neurological Emergencies: Diagnostic Accuracy and Impact on Patient Management

OBJECTIVES

The aim of this study was to investigate diagnostic accuracy and impact on patient management of an ultrafast (4:33 minutes/5 sequences) brain magnetic resonance imaging (MRI) protocol for the detection of intracranial pathologies in acute neurological emergencies.

MATERIALS AND METHODS

Four hundred forty-nine consecutive emergency patients with acute nontraumatic neurological symptoms were evaluated for this institutional review board-approved prospective single-center trial. Sixty patients (30 female, 30 male; mean age, 61 years) with negative head CT were included and underwent emergency brain MRI at 3 T subsequent to CT. MRI included the ultrafast protocol (ultrafast-MRI; sag T1 GRE, ax T2 TSE, ax T2 TSE Flair, ax T2* EPI-GRE, ax DWI SS-EPI; TA, 5 minutes) and an equivalent standard-length protocol (TA, 15 minutes) as reference standard. Two blinded board-certified neuroradiologists independently analyzed the MRI with regard to image quality (1, nondiagnostic; 2, substantial artifacts; 3, satisfactory; 4, minor artifacts; 5, no artifacts) and intracranial pathologies. Sensitivity and specificity for the detection of intracranial pathologies were calculated accordingly.

RESULTS

Ninety-three additional intracranial lesions (acute ischemia, n = 21; intracranial hemorrhage/microbleeds, n = 27; edema, n = 2; white matter lesion, n = 38; chronic infarction, n = 3; others, n = 2) were detected by ultrafast-MRI, whereas 101 additional intracranial lesions were detected by the standard-length protocol (acute ischemia, n = 24; intracranial hemorrhage/microbleeds, n = 32; edema, n = 2; white matter lesion, n = 38; chronic infarction, n = 3; others, n = 2). Image quality was equivalent to the standard-length protocol. Ultrafast-MRI demonstrated high diagnostic accuracy (sensitivity, 0.939 [0.881-0.972]; specificity, 1.000 [0.895-1.000]) for the detection of intracranial pathologies. MRI led to a change in patient management in 10% compared with the initial CT.

CONCLUSIONS

Ultrafast-MRI enables time-optimized diagnostic workup in acute neurological emergencies at high sensitivity and specificity compared with a standard-length protocol, with direct impact on patient management. Ultrafast MRI protocols are a powerful tool in the emergency setting and may be implemented on various scanner types based on the optimization of individual acquisition parameters.

Simultaneous time of flight-MRA and T2* imaging for cerebrovascular MRI

PURPOSE

3D multi-echo gradient-recalled echo (ME-GRE) can simultaneously generate time-of-flight magnetic resonance angiography (pTOF) in addition to T2*-based susceptibility-weighted images (SWI). We assessed the clinical performance of pTOF generated from a 3D ME-GRE acquisition compared with conventional TOF-MRA (cTOF).

METHODS

Eighty consecutive children were retrospectively identified who obtained 3D ME-GRE alongside cTOF. Two blinded readers independently assessed pTOF derived from 3D ME-GRE and compared them with cTOF. A 5-point Likert scale was used to rank lesion conspicuity and to assess for diagnostic confidence.

RESULTS

Across 80 pediatric neurovascular pathologies, a similar number of lesions were reported on pTOF and cTOF (43-40%, respectively, p > 0.05). Rating of lesion conspicuity was higher with cTOF (4.5 ± 1.0) as compared with pTOF (4.0 ± 0.7), but this was not significantly different (p = 0.06). Diagnostic confidence was rated higher with cTOF (4.8 ± 0.5) than that of pTOF (3.7 ± 0.6; p < 0.001). Overall, the inter-rater agreement between two readers for lesion count on pTOF was classified as almost perfect (κ = 0.98, 96% CI 0.8-1.0).

CONCLUSIONS

In this study, TOF-MRA simultaneously generated in addition to SWI from 3D MR-GRE can serve as a diagnostic adjunct, particularly for proximal vessel disease and when conventional TOF-MRA images are absent.

Role of a modified ultrafast MRI brain protocol in clinical paediatric neuroimaging

AIM

To establish a role for modified ultrafast magnetic resonance imaging (MRI) of the brain in clinical paediatric patients based on clinically acceptable image quality and diagnostic accuracy.

MATERIALS AND METHODS

A prospective study was conducted with institutional review board approval on an ultrafast MRI brain protocol consisting of sagittal T1-weighted, axial T2-weighted, axial fluid-attenuated inversion recovery (FLAIR), axial diffusion-weighted imaging (DWI), and axial T2∗-weighted sequences. Preliminary investigations revealed that the default ultrafast T2-weighted sequence was prone to pulsation artefacts. A modified ultrafast T2-weighted sequence was therefore developed to replace the default ultrafast T2-weighted sequence. Thirty-five patients with clinical indication for neuroimaging underwent ultrafast MRI, modified ultrafast T2-weighted sequence and standard MRI at 3 T. Image quality of ultrafast MRI sequences were graded as clinically "diagnostic" or "non-diagnostic" and compared against the corresponding standard MRI sequences as the reference standard. The modified ultrafast T2-weighted sequence surpassed the default ultrafast T2-weighted sequence in image quality. The ultrafast MRI protocol was therefore replaced with the modified ultrafast T2-weighted sequence creating a modified ultrafast MRI protocol. The clinical reports of modified ultrafast MRI were compared against standard MRI for diagnostic concordance, categorised further as "normal", "clinically significant", or "clinically minor" abnormalities.

RESULTS

Ultrafast T1-weighted, FLAIR, and DWI sequences had comparable image quality to standard MRI sequences. The ultrafast T2∗-weighted sequence had significantly higher non-diagnostic images (42.9%) compared to the standard MRI sequence (2.9%). The default ultrafast T2-weighted sequence had significantly higher non-diagnostic images compared to the modified ultrafast T2-weighted sequence and standard T2-weighted sequence (82.9%, 5.7%, 8.6%, respectively). There was 100% concordance for normal and clinically significant abnormalities and 23% discordance for clinically minor abnormalities. Modified ultrafast MRI takes 5 minutes 41 seconds compared to standard MRI time of 14 minutes 57 seconds.

CONCLUSION

The modified ultrafast MRI protocol for brain imaging demonstrates clinically acceptable image quality in four out of five sequences and has high accuracy in diagnosing normal and clinically significant abnormalities when compared against the standard MRI protocol for brain imaging. It could potentially benefit a select group of paediatric patients who require neuroimaging.

Development and Implementation of a Pilot Radiation Reduction Protocol for Pediatric Head Injury

BACKGROUND

Traumatic brain injury is the leading cause of morbidity and mortality for children in the United States. The aim of this study was to develop and implement a guideline to reduce radiation exposure in the pediatric head injury patient by identifying the patient population where repeat imaging is necessary and to establish rapid brain protocol magnetic resonance imaging as the first-line modality.

METHODS

A retrospective chart review of trauma patients between 0 and 14 y of age admitted at a pediatric level 2 trauma center was performed between January 2013 and June 2019. The guideline established the appropriateness of repeat scans for patients with Glasgow Coma Scale >13 with clinical neurological deterioration or patients with Glasgow Coma Scale ≤13 and intracranial hemorrhagic lesion on initial head computed tomography (CT).

RESULTS

Our trauma registry included 592 patients during the study period, 415 before implementation and 161 after implementation. A total of 132 patients met inclusion criteria, 116 pre-guideline and 16 post-guideline. The number of patients receiving repeat head CTs significantly decreased from 34.5% to 6.3% (P < 0.02). There was also a significant decrease in the mean number of head CT/patient pre-guideline 1.63 (range 1-7) compared with post-guideline 1.06 (range 1-2) (P < 0.02).

CONCLUSIONS

CT head imaging is invaluable in the initial trauma evaluation of pediatric patients. However, it can be overused, and the radiation may lead to long-term deleterious effects. Establishing a head imaging guideline which limits use with clinical criteria can be effective in reducing radiation exposure without missing injuries.

One-Minute Ultrafast Brain MRI With Full Basic Sequences: Can It Be a Promising Way Forward for Pediatric Neuroimaging?

OBJECTIVE. The long scan time of brain MRI is a major drawback that limits its clinical use for evaluating pediatric patients who are inherently prone to motion and frequently require sedatives. This study investigated the clinical feasibility of a 1-minute ultrafast brain MRI protocol in pediatric patients by assessing its image quality in comparison with that of routine brain MRI. MATERIALS AND METHODS. Twenty-three patients were enrolled who underwent 1-minute ultrafast MRI and routine brain MRI protocols including five essential sequences (T1-weighted imaging, T2-weighted imaging, DWI, FLAIR, and T2*-weighted imaging). Total scan time for the same image contrast levels was 1 minute 11 seconds for ultrafast MRI versus 9 minutes 51 seconds for routine brain MRI. Two readers independently reviewed all images from the two MRI protocols and graded the image quality on a 4-point Likert scale. The Wilcoxon signed rank test was used to compare the readers' ratings; interobserver agreement between the readers was also assessed. RESULTS. Although the mean scores of overall image quality and anatomic delineation in ultrafast brain MR images were significantly lower than those in routine brain MR images, ultrafast brain MRI showed sufficient overall image quality and anatomic delineation with more than 2 points on the 4-point scale. CONCLUSION. The 1-minute ultrafast brain MRI protocol showed at least sufficient image quality compared with routine brain MRI. Therefore, 1-minute ultrafast brain MRI can be a viable first-line neuroimaging study for pediatric patients because of its shorter scan time, absence of radiation hazard, and reduced sedation requirements.

Clinical Experience of 1-Minute Brain MRI Using a Multicontrast EPI Sequence in a Different Scan Environment

BACKGROUND AND PURPOSE

The long scan time of MR imaging is a major drawback limiting its clinical use in neuroimaging; therefore, we aimed to investigate the clinical feasibility of a 1-minute full-brain MR imaging using a multicontrast EPI sequence on a different MR imaging scanner than the ones previously reported.

MATERIALS AND METHODS

We retrospectively reviewed the records of 146 patients who underwent a multicontrast EPI sequence, including T1-FLAIR, T2-FLAIR, T2WI, DWI, and T2*WI sequences. Two attending neuroradiologists assessed the image quality of each sequence to compare the multicontrast EPI sequence with routine MR imaging protocols. We used the Wilcoxon signed rank test and McNemar test to compare the 2 MR imaging protocols.

RESULTS

The multicontrast EPI sequence generally showed sufficient image quality of >2 points using a 4-point assessment scale. Regarding image quality and susceptibility artifacts, there was no significant difference between the multicontrast EPI sequence DWI and routine DWI (P > .05), attesting to noninferiority of the multicontrast EPI, whereas there were significant differences in the other 4 sequences between the 2 MR imaging protocols.

CONCLUSIONS

The multicontrast EPI sequence showed sufficient image quality for clinical use with a shorter scan time; however, it was limited by inferior image quality and frequent susceptibility artifacts compared with routine brain MR imaging. Therefore, the multicontrast EPI sequence cannot completely replace the routine MR imaging protocol at present; however, it may be a feasible option in specific clinical situations such as screening, time-critical diseases or for use with patients prone to motion.

Rapid brain MRI protocols reduce head computerized tomography use in the pediatric emergency department

BACKGROUND

Rapid magnetic resonance imaging (MRI) protocols may be effective in the emergency department (ED) to evaluate nontraumatic neurologic complaints. We evaluate neuroimaging (rapid MRI [rMRI]), head computerized tomography [HCT], and full MRI) use following widespread implementation of rMRI protocols in a pediatric emergency department (ED).

METHODS

We conducted a retrospective study in a tertiary care pediatric ED of encounters with neuroimaging during two 9-month periods: one prior to (control period) and one after generalized availability of 4 rMRI protocols (rMRI period). The primary outcome was differences in neuroimaging rates between the two periods. Secondary outcomes included ED process measures, unsuccessful imaging, and undetected pathology, with full MRI within 14 days as the reference standard.

RESULTS

There were 1052 encounters with neuroimaging during the control and 1308 during the rMRI periods. Differences in neuroimaging between periods were 27.7% for rMRI (95% CI, 24.4, 31.0), - 21.5% for HCT (95% CI, - 25.5, - 17.5), and - 6.2% for full MRI (95% CI, - 9.3, - 3.1%.) Time to imaging (182 [IQR 138-255] versus 86 [IQR 52-137] minutes) as well as ED length of stay (396 [IQR 304-484] versus 257 [IQR 196-334] minutes) was longer for rMRI versus HCT (p < 0.01). Between the control and rMRI periods, there were differences in types of neuroimaging performed for patients with altered mental status, headache, seizure, shunt dysfunction, stroke, syncope, trauma, vomiting, infection, and other neurologic complaints (p < 0.05). rMRI studies were unsuccessful in 3.6% of studies versus 0.0% of HCTs (p < 0.01). The 22 unsuccessful rMRI studies were unsuccessful due to artifacts from dental hardware (n = 2) and patient motion (n = 20). None of the rMRI studies with full MRI follow-up imaging had undetected pathology; the false negative rate for the HCT exams was as high as 25%.

CONCLUSIONS

After routine ED use of 4 rMRI protocols, there was a more than 20% decrease in HCT use without missed diagnoses. Time to neuroimaging and length of stay were longer for rMRI than HCT, with higher rates of unsuccessful imaging. Despite these limitations, rMRI may be an alternative to HCT for nontraumatic complaints in the ED.

[Magnetic resonance imaging of the brain in neonates and infants]

Magnetic resonance imaging (MRI) is increasingly being used for infants and small children due to rapid sequence protocols, broader scanner availability and good monitoring possibilities. The sequence protocol should always be adapted to the individual clinical needs of the infant or toddler. For some clinical indications, such as control of ventricular width in children with shunted hydrocephalus, ultrafast protocols can be used with a scanning time of just a few minutes. For more complex clinical questions, more extensive sequence protocols are warranted. Particularly for neonates and using a rapid investigation protocol, MRI examinations can very often be performed without sedation. The necessity of using gadolinium-based contrast agents has to be critically deliberated in infants and neonates and has to be exactly tailored to the clinical needs. In many cases MRI examinations of the brain in infants and neonates do not require gadolinium-based contrast agents.

MRI Findings in Pediatric Abusive Head Trauma: A Review

Trauma is the most common cause of death and significant morbidity in childhood; abusive head trauma (AHT) is a prominent cause of significant morbidity and mortality in children younger than 2 years old. Correctly diagnosing AHT is challenging both clinically and radiologically. The primary diagnostic challenges are that the abused children are usually too young to provide an adequate history, perpetrators are unlikely to provide truthful account of trauma, and clinicians may be biased in their assessment of potentially abused children. The main radiological challenge is that there is no single imaging finding that is independently specific for or diagnostic of AHT. The radiological evaluation should be based on the multiplicity and severity of findings and an inconsistency with the provided mechanism of trauma. While the most common neuroimaging finding in AHT is subdural hemorrhage, other less well-known magnetic resonance imaging (MRI) findings such as the "lollipop sign" or "tadpole sign," parenchymal or cortical lacerations, subpial hemorrhage, cranio-cervical junction injuries including retroclival hematomas, as well as diffuse hypoxic brain injury have been identified and described in the recent literature. While AHT is ultimately a clinical diagnosis combining history, exam, and neuroimaging, familiarity with the typical as well as the less-well known MRI findings will improve recognition of AHT by radiologists.

Feasibility and Accuracy of Fast MRI Versus CT for Traumatic Brain Injury in Young Children

BACKGROUND

Computed tomography (CT) is commonly used for children when there is concern for traumatic brain injury (TBI) and is a significant source of ionizing radiation. Our objective was to determine the feasibility and accuracy of fast MRI (motion-tolerant MRI sequences performed without sedation) in young children.

METHODS

In this prospective cohort study, we attempted fast MRI in children <6 years old who had head CT performed and were seen in the emergency department of a single, level 1 pediatric trauma center. Fast MRI sequences included 3T axial and sagittal T2 single-shot turbo spin echo, axial T1 turbo field echo, axial fluid-attenuated inversion recovery, axial gradient echo, and axial diffusion-weighted single-shot turbo spin echo planar imaging. Feasibility was assessed by completion rate and imaging time. Fast MRI accuracy was measured against CT findings of TBI, including skull fracture, intracranial hemorrhage, or parenchymal injury.

RESULTS

Among 299 participants, fast MRI was available and attempted in 225 (75%) and completed in 223 (99%). Median imaging time was 59 seconds (interquartile range 52-78) for CT and 365 seconds (interquartile range 340-392) for fast MRI. TBI was identified by CT in 111 (50%) participants, including 81 skull fractures, 27 subdural hematomas, 24 subarachnoid hemorrhages, and 35 other injuries. Fast MRI identified TBI in 103 of these (sensitivity 92.8%; 95% confidence interval 86.3-96.8), missing 6 participants with isolated skull fractures and 2 with subarachnoid hemorrhage.

CONCLUSIONS

Fast MRI is feasible and accurate relative to CT in clinically stable children with concern for TBI.

MR Imaging in Neurocritical Care

How to cite this article: Patra A, Janu A, Sahu A. MR Imaging in Neurocritical Care. Indian J Crit Care Med 2019;23(Suppl 2):S104–S114.

The neuroimaging mimics of abusive head trauma

Abusive head trauma (AHT) is a significant cause of morbidity and mortality in the paediatric population, typically in children under the age of two years. Neuroimaging plays a key role in the diagnostic work up of these patients as information regarding the mechanism of injury is often lacking and the findings on examination can be nonspecific. A number of conditions, both traumatic and atraumatic can mimic AHT based on neuroimaging features alone. The repercussions associated with a diagnosis or misdiagnosis of AHT can be severe and radiologists therefore need to be aware of and familiar with the imaging differentials of AHT. In this paper we review the imaging findings of the radiological mimics of AHT and focus on features that can help differentiate these entities from AHT.

Prevalence, Patterns, and Clinical Relevance of Hypoxic-Ischemic Injuries in Children Exposed to Abusive Head Trauma

BACKGROUND AND PURPOSE

Hypoxic-ischemic injuries (HIIs) are a scarcely investigated but important cause of morbidity and mortality in children who suffered abusive head trauma (AHT). The purpose of this study is to determine: (a) prevalence, types, and clinical relevance of cytotoxic edema compatible with HII in nonpenetrating AHT, (b) their relationship to other classic neuroimaging findings of AHT, and (c) their correlation with clinical outcomes.

METHODS

Diffusion-weighted imaging sequences of magnetic resonance imagings performed on children under 5 years diagnosed with AHT were reviewed to detect the most common patterns of acute parenchymal damage. Patterns of cytotoxic edema were described, and HII-compatible ones divided in subtypes. Correlation between HII, fractures, and subdural hemorrhages (SDHs) and with clinical outcomes was determined using imaging and available follow-up data.

RESULTS

Out of 57 patients, 36.8% showed lesions compatible with HII. A predominantly asymmetric cortical distribution was observed in 66.7% of cases, while 33.3% had diffused both cortical and deep gray/white matter distribution injury. Traumatic axonal injuries and focal contusions were less common. There was no significant correlation between the presence of SDH (P = .6) or skull fractures (P = .53) and HII. HII was the most severe form of parenchymal damage in terms of in-hospital mortality and morbidity at follow-up.

CONCLUSIONS

HII is the most common type of parenchymal damage in children victim of AHT, being present in 1/3 of patients with this condition, and correlates with more severe outcomes. Its presence is independent from other classic traumatic findings such as SDH and fractures.