Rapid sequence magnetic resonance imaging in the assessment of children with hydrocephalus

Non-sedated fast spine magnetic resonance imaging in pediatric patients

BACKGROUND

Traditional spine magnetic resonance imaging (MRI) protocols require sedation in young children and uncooperative patients. There is an increased interest in non-sedated pediatric MRI protocols to reduce risks associated with anesthetic agents and improve MRI access.

OBJECTIVE

To evaluate the image quality of pediatric non-sedated fast spine MRI.

MATERIALS AND METHODS

We retrospectively reviewed 69 pediatric non-sedated fast spine MRI exams performed in 57 patients. Two blinded readers provided image quality ratings for the evaluation of bones, cranio-cervical junction, cerebrospinal fluid (CSF) spaces, spinal cord, soft tissues, ligaments, and overall diagnostic quality on a 1-5 scale, and determined whether there was evidence of syringomyelia, abnormal conus medullaris position, or filum terminale abnormality.

RESULTS

Mean patient age was 7.2 years (age range ≤ 1-17). Indications included syringomyelia (n=25), spinal dysraphism (n=4), combination of both syringomyelia and spinal dysraphism (n=8), and other miscellaneous indications (n=32). The inter-observer agreement ranged between moderate and very good for each variable (Cohen's weighted kappa] range=0.45-0.69). The highest image quality ratings were given to CSF spaces (mean image quality=3.5/5 ± 0.8) and cranio-cervical junction evaluations (3.5/5 ± 0.9). Overall diagnostic quality was worst in the  <5 years group (P=0.006). Readers independently identified a cervical spinal cord syrinx in 6 cases, and 1 mm spinal cord central canal dilation in one case. Readers agreed on the position of the conus medullaris in 92% of cases (23/25 cases).

CONCLUSION

Non-sedated pediatric spine MRI can be an effective diagnostic test to evaluate for spine pathology, especially syringomyelia, Chiari malformation, and conus medullaris anatomy.

Validation of a shortened MR imaging protocol for pediatric spinal pathology

OBJECTIVE

Conventional pediatric spine MRI protocols have multiple sequences resulting in long acquisition times. Sedation is consequently required. This study evaluates the diagnostic capability of a limited MRI spine protocol for selected common pediatric indications.

METHODS

Spine MRIs at CHEO between 2017 and 2020 were reviewed across pediatric patients younger than four years old. Two blinded neuroradiologists reviewed limited scan sequences, and results were independently compared to previously reported findings from the complete imaging series. T2 sagittal sequences from the craniocervical junction to sacrum and T1 axial sequence of the lumbar spine constitute the short protocol, with the outcomes of interest being cerebellar ectopia, syrinx, level of conus, filum < 2 mm, fatty filum, and spinal dysraphism.

RESULTS

A total of 105 studies were evaluated in 54 male and 51 female patients (mean age 19.2 months). The average combined scan time of the limited sequences was 15 min compared to 35 min for conventional protocols (delta = 20 min). The average percent agreement between full and limited sequences was > 95% in all but identifying a filum < 2 mm, where the percent agreement was 87%. Using limited MR sequences had high sensitivity (> 0.91) and specificity (> 0.99) for the detection of cerebellar ectopia, syrinx, fatty filum, and spinal dysraphism.

CONCLUSION

This study demonstrates that selected spinal imaging sequences allow for consistent and accurate diagnosis of specific clinical conditions. A limited spine imaging protocol has potential as a screening test to reduce the need for full-sequence MRI scans. Further work is needed to determine utility of selected imaging for other clinical indications.

MRI as a one-stop destination for evaluation of CSF shunt malfunction

Background

Despite the high-frequency rate of cerebrospinal fluid shunt malfunction, radiological evaluation of CSF shunts has remained deficient, focusing mainly on demonstrating secondary signs of shunt failure rather than evaluating the shunt tube itself. We aimed to study the utility of different MR pulse sequences in evaluating the cranial and abdominal ends of CSF shunts in order to identify the potential cause of shunt failure and its impact on patient management.

Results

Twenty-five patients (18 males, 7 females, median age 2.5 years, IQR 0.75–15) were enrolled in the study, having 28 ventriculo-peritoneal shunts and single ventriculo-gallbladder shunt. The catheter lumen and fine intraventricular septae were only demonstrated in 3D-DRIVE sequences (p < 0.001). Except for three patients (having cranial end-related complications), all patients with cranial and/or abdominal end-related complications received surgery (p < 0.001, positive likelihood and negative likelihood ratios = 7.27, 0.3, respectively, sensitivity = 0.7 and specificity = 0.9). MRI findings (luminal occlusion, disconnection, CSF collection, or migration) were consistent with operative data. There is no significant difference between patients who underwent surgery and those with conservative management, or symptomatic and asymptomatic patients in terms of the prevalence of ventricular dilatation or white matter signal abnormality. The results of the abdomino-pelvic fat-suppressed T2-WI showed excellent agreement with ultrasound findings (Cohen’s Kappa 0.9). Quantitative PC could give insights into CSF dynamics, which depend on the site and cause of shunt malfunction.

Conclusions

MRI could be a one-stop destination for evaluating patients with suspected non-acute shunt malfunction. It was found to have clinical relevance in terms of accurately locating the exact site and possible cause of shunt-related complications.

Hydrocephalus surveillance following CSF diversion: a modified Delphi study

OBJECTIVE

Long-term follow-up is often recommended for patients with hydrocephalus, but the frequency of clinical follow-up, timing and modality of imaging, and duration of surveillance have not been clearly defined. Here, the authors used the modified Delphi method to identify areas of consensus regarding the modality, frequency, and duration of hydrocephalus surveillance following surgical treatment.

METHODS

Pediatric neurosurgeons serving as institutional liaisons to the Hydrocephalus Clinical Research Network (HCRN), or its implementation/quality improvement arm (HCRNq), were invited to participate in this modified Delphi study. Thirty-seven consensus statements were generated and distributed via an anonymous electronic survey, with responses structured as a 4-point Likert scale (strongly agree, agree, disagree, strongly disagree). A subsequent, virtual meeting offered the opportunity for open discussion and modification of the statements in an effort to reach consensus (defined as ≥ 80% agreement or disagreement).

RESULTS

Nineteen pediatric neurosurgeons participated in the first round, after which 15 statements reached consensus. During the second round, 14 participants met virtually for review and discussion. Some statements were modified and 2 statements were combined, resulting in a total of 36 statements. At the conclusion of the session, consensus was achieved for 17 statements regarding the following: 1) the role of standardization; 2) preferred imaging modalities; 3) postoperative follow-up after shunt surgery (subdivided into immediate postoperative imaging, delayed postoperative imaging, routine clinical surveillance, and routine radiological surveillance); and 4) postoperative follow-up after an endoscopic third ventriculostomy. Consensus could not be achieved for 19 statements.

CONCLUSIONS

Using the modified Delphi method, 17 consensus statements were developed with respect to both clinical and radiological follow-up after a shunt or endoscopic third ventriculostomy. The frequency, modality, and duration of surveillance were addressed, highlighting areas in which no clear data exist to guide clinical practice. Although further studies are needed to evaluate the clinical utility and cost-effectiveness of hydrocephalus surveillance, the current study provides a framework to guide future efforts to develop standardized clinical protocols for the postoperative surveillance of patients with hydrocephalus. Ultimately, the standardization of hydrocephalus surveillance has the potential to improve patient care as well as optimize the use of healthcare resources.

The Use of Rapid Sequence Magnetic Resonance Imaging of the Brain as a Screening Tool for the Detection of Gross Intracranial Pathology in Children Presenting to the Emergency Department With a Chief Complaint of Persistent or Recurrent Headaches

OBJECTIVE

The purpose of the study, was to assess the utility of rapid sequence brain magnetic resonance imaging (RS-MRI), as a screening tool to detect gross intracranial pathology in children that present to the emergency department, with a chief complaint of persistent or recurrent headaches. Rapid sequence MRI of the brain is a radiation-free technique that is used to evaluate ventricular size in children with shunted hydrocephalus, who present to the emergency department with symptomatology consistent with shunt malfunction.

METHODS

The study evaluated RS-MRI radiographic findings of 105 children that presented to a busy tertiary care pediatric emergency/trauma center between May 1, 2013, and May 31, 2015. The inclusion criteria for the study are as follows: (1) patient's age up to 12 years, (2) patient history of persistent or recurrent headaches, (3) no history of recent specialized intracranial imaging studies. The exclusion criteria are as follows: (1) a history of recent head injury or trauma, (2) known intracranial pathology, (3) clinical findings consistent with intracranial pathology, (4) patients that required intraprocedural sedation. A detailed explanation was given to the patient's parents/guardian, specifying that this was a "screening test" for detection of gross intracranial abnormalities and not a complete radiological evaluation that would rule out all pathology. Appropriate informed consent was obtained by the attending emergency medicine specialist, and was documented in the patient's medical record.

RESULTS

A total of 105 RS-MRI examinations were performed with an average imaging time of 75 seconds. None of the children required intraprocedural sedation, and there were no failed examinations. One patient was excluded from the study due to a pilocytic astrocytoma (not disclosed initially). There were 81 (77%) of 105 normal studies and 24 (23%) of 105 abnormal studies. One patient returned to the emergency department 2 times and was enrolled twice during the 2-year study. Of the 24 abnormal studies, 18 (75%) of 24 cases were diagnosed with sinusitis, and 1 (4.1%) of 24 cases was diagnosed with an abnormal brain mass with mild hydrocephalus due to obstruction of the caudal aspect of the fourth ventricle.

CONCLUSIONS

Rapid sequence MRI is a radiation-free useful alternative to computer tomography of the brain, when used as a screening tool for children with persistent or recurrent headaches presenting to the emergency department. This rapid imaging modality was particularly useful in identifying children with sinus disease, and contributed significantly to patient/family satisfaction with the care they receive during the emergency department visit. Additionally, RS-MRI screening was successful in detecting a serious neurosurgical emergency in one child with a cerebellar mass causing increased intracranial pressure. Further studies with large sample size are needed to corroborate our findings.

'Possible shunt malfunction' pathway for paediatric hydrocephalus-a study of clinical outcomes and cost implications

BACKGROUND

Shunt insertion for hydrocephalus is a common paediatric neurosurgery procedure. Shunt complications are frequent with an estimated 20-40% failure rate within the first year, and 4.5% per year subsequently. We have an open-door 'possible shunt malfunction' pathway for children treated with a shunt or endoscopic third ventriculostomy, providing direct ward access to ensure rapid assessment and timely management of children.

OBJECTIVE

To audit the 'possible shunt malfunction' pathway in terms of clinical outcomes (percentage-confirmed shunt dysfunction and number of re-attendances) and costs.

METHODS

Clinical data for patients attending the triage service were prospectively recorded over 7 months-including the number of attendances, previous shunt revisions, shunt type, investigations performed (CT, x-rays), and outcome. Costings (e.g. costs of physician, inpatient stay, investigations) were obtained from the hospital's procurement department.

RESULTS

In the study period, there were 81 attendances by 62 patients and only 16% of attendances resulted in surgical management (either shunt revision or ETV). Approximately 17% of patients re-attended at least once. The average cost per attendance in our pathway was £765.57 ($969.63; €858.73). The total expenditure for the pathway over 7 months was £62,011.03 ($78,540.07; €69,556.81), with inpatient stay making up the biggest percentage of cost (49.2%).

CONCLUSION

Only 16% (13 attendances) of those attending through our pathway required neurosurgical intervention. Investigations for possible blocked shunt come at significant health, social, and financial cost. High rates of shunt failure, re-attendance, investigations, and inpatient stays incur a sizable financial burden to the healthcare system.

Planning and Osteotomy Designs in the Correction of Single-Suture Craniosynostosis

BACKGROUND

Craniosynostosis is among the abnormalities that are more commonly encountered by craniofacial surgeons. Although the overall concepts for cranial vault remodeling are relatively simple, osteotomy designs and methods for calvarial rearrangement are highly varied. In this work, we present a summary of the known designs for correction of single-suture craniosynostosis.

METHODS

A review of the literature was performed of the more frequently used osteotomy designs for single-suture craniosynostosis, as well as their reported results and outcomes. Also reviewed are some of the current available approaches for the diagnosis and surgical planning for single-suture craniosynostosis.

RESULTS

There remains a diversity of techniques available for the reconstruction of each fused cranial suture. Certain osteotomy designs are reported in the literature and are used by craniofacial surgeons more frequently. Each has its own benefits and disadvantages, and there is a growing body of outcome data available to guide surgical decision-making. Regarding diagnosis and surgical planning, computed tomography with 3-dimensional reconstruction remains the diagnostic standard of care, and efforts are ongoing to develop and implement new diagnostic modalities like Black Bone MRI to reduce radiation exposure.

CONCLUSIONS

There has been ongoing evolution of the surgical techniques available to reconstruct single-suture craniosynostosis, leading to ever-improving patient outcomes.

Routine postoperative computed tomography scan after craniotomy: systematic review and evidence-based recommendations

Over the last few years, the role of early postoperative computed tomography (EPOCT) after cranial surgery has been repeatedly questioned, but there is yet no consensus on the practice. We conducted a systematic review to address the usefulness of EPOCT in association with neurological examination after elective craniotomies compared to the neurological examination alone. Studies were eligible if they provided information about the number of patients scanned, how many were asymptomatic or presented neurological deterioration before the scan and how many of each of those groups had their management changed due to imaging findings. CTs had to be performed in the first 48 h following surgery to be considered early. Eight studies were included. The retrospective studies enrolled a total of 3639 patients, with 3737 imaging examinations. Out of the 3696 CT scans performed in asymptomatic patients, less than 0.8% prompted an intervention, while 100% of patients with neurological deterioration were submitted to emergency surgery. Positive predictive values of altered scans were 0.584 for symptomatic patients and 0.125 for the asymptomatic. The number of altered scans necessary to predict (NNP) one change in management for the asymptomatic patients was 8, while for the clinically evident cases, it was 1.71. The number of scans needed to diagnose one clinically silent alteration is 134.75, and postoperative imaging of neurologically intact patients is 132 times less likely to issue an emergency intervention than an altered neurological examination alone. EPOCT following elective craniotomy in neurologically preserved patients is not supported by current evidence, and CT scanning should be performed only in particular conditions. The authors have developed an algorithm to help the judgment of each patient by the surgeon in a resource-limited context.

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.

Management of Hydrocephalus in Children: Anatomic Imaging Appearances of CSF Shunts and Their Complications

OBJECTIVE. This article addresses the management of hydrocephalus and the CSF shunts used to treat this entity. CONCLUSION. CSF shunts have a high failure rate. Imaging plays a pivotal role in assessing CSF shunt failure and determining the need for surgical revision. An in-depth knowledge of CSF shunt components, their failure modes, and the corresponding findings on anatomic imaging studies is necessary to ensure timely diagnosis and prevent permanent neurologic damage.

Reliability of the radiopharmaceutical shunt flow study for the detection of a CSF shunt malfunction in the presence of stable ventricular size

OBJECTIVE

The authors sought to determine the reliability of a radiopharmaceutical (RP) shunt flow study for the detection of a CSF-diverting shunt malfunction in the presence of stable ventricular size.

METHODS

After the authors obtained IRB approval, all CSF RP shunt flow studies done between January 1, 2014, and January 1, 2019, in pediatric patients at Children's Hospital Los Angeles were identified. Included in the study were only those patients in whom an MRI or CT scan was done during the hospital admission for shunt malfunction and showed no increase in ventricular size compared with the most recent prior MRI or CT scan when the patient was asymptomatic. Data recorded for analysis were patient age and sex, etiology of the hydrocephalus, shunt distal site, nonprogrammable versus programmable valve, operative findings if the shunt was revised, and follow-up findings for a minimum of 90 days after admission. The RP shunt flow study consisted of tapping the reservoir and injecting technetium-99m DTPA according to a set protocol.

RESULTS

The authors identified 146 RP flow studies performed in 119 patients meeting the above criteria. Four of the 146 RP studies (3%) were nondiagnostic secondary to technical failure and were excluded from statistical analysis. Of the 112 normal flow studies, operative intervention was not undertaken in 102 (91%). The 10 (9%) remaining normal studies were performed in patients who underwent operative intervention, in which 8 patients had a proximal obstruction, 1 had a distal obstruction, and 1 patient had no obstruction. Of the 30 patients with abnormal flow studies, symptoms of shunt malfunction subsided in 9 (30%) patients and these patients did not undergo operative intervention. Of the 21 (70%) operated patients, obstruction was proximal in 9 patients and distal in 5, and for 7 patients the shunt tubing was either fractured or disconnected. Regression analysis indicated a significant association between the flow study interpretation and the odds for shunt revision (OR 27, 95% CI 10-75, p < 0.0001). No other clinical variables were significant. The sensitivity of a shunt flow study alone for detection of shunt malfunction in cases with stable ventricular size was the same as a shunt flow study plus an MRI or CT (70% vs 70%), but performing a shunt flow in addition to MRI or CT did increase the specificity from 92% to 100% and the accuracy from 87% to 94%.

CONCLUSIONS

RP shunt flow studies were of definite value in deciding whether to operatively intervene in patients with symptoms of shunt malfunction in whom no change in ventricular size was detected on current MRI or CT scans compared to scans obtained when the patients were asymptomatic.

Semantic segmentation of cerebrospinal fluid and brain volume with a convolutional neural network in pediatric hydrocephalus-transfer learning from existing algorithms

Background

For the segmentation of medical imaging data, a multitude of precise but very specific algorithms exist. In previous studies, we investigated the possibility of segmenting MRI data to determine cerebrospinal fluid and brain volume using a classical machine learning algorithm. It demonstrated good clinical usability and a very accurate correlation of the volumes to the single area determination in a reproducible axial layer. This study aims to investigate whether these established segmentation algorithms can be transferred to new, more generalizable deep learning algorithms employing an extended transfer learning procedure and whether medically meaningful segmentation is possible.

Methods

Ninety-five routinely performed true FISP MRI sequences were retrospectively analyzed in 43 patients with pediatric hydrocephalus. Using a freely available and clinically established segmentation algorithm based on a hidden Markov random field model, four classes of segmentation (brain, cerebrospinal fluid (CSF), background, and tissue) were generated. Fifty-nine randomly selected data sets (10,432 slices) were used as a training data set. Images were augmented for contrast, brightness, and random left/right and X/Y translation. A convolutional neural network (CNN) for semantic image segmentation composed of an encoder and corresponding decoder subnetwork was set up. The network was pre-initialized with layers and weights from a pre-trained VGG 16 model. Following the network was trained with the labeled image data set. A validation data set of 18 scans (3289 slices) was used to monitor the performance as the deep CNN trained. The classification results were tested on 18 randomly allocated labeled data sets (3319 slices) and on a T2-weighted BrainWeb data set with known ground truth.

Results

The segmentation of clinical test data provided reliable results (global accuracy 0.90, Dice coefficient 0.86), while the CNN segmentation of data from the BrainWeb data set showed comparable results (global accuracy 0.89, Dice coefficient 0.84). The segmentation of the BrainWeb data set with the classical FAST algorithm produced consistent findings (global accuracy 0.90, Dice coefficient 0.87). Likewise, the area development of brain and CSF in the long-term clinical course of three patients was presented.

Conclusion

Using the presented methods, we showed that conventional segmentation algorithms can be transferred to new advances in deep learning with comparable accuracy, generating a large number of training data sets with relatively little effort. A clinically meaningful segmentation possibility was demonstrated.

[Hydrocephalus in newborns and infants at the Nouakchott National Hospital]

Neonatal and infant hydrocephalus is an important factor for mortality and morbidity in developing countries with limited diagnostic and therapeutic means. The purpose of this study was to report our experience in the management of this disease in Mauritania. We conducted a retrospective study of 126 medical records of newborns aged 0-24 months treated for hydrocephalus in the Department of Neurosurgery at the Nouakchott National Hospital from June 2014 to June 2018. Mean follow-up time was 15 months (9-27 months). The average age of patients was 5 months (2 days-20 months). Highest prevalence was observed among female babies (sex ratio 0.77). Our case series consisted of 45 newborns (35.7%) and 81 infants (64.3%). A history of infection during pregnancy was found in 19.8% of cases and neonatal infection in 23.8% of cases. Clinically, 87.3% had macrocephalus, 35.7% had psychomotor retardation and 15.8% refused to suckle. The main cause was myelomeningocele (23.8%), followed by meningitis (15.8%). Ventriculo-peritoneal derivation (VPD) was the first-line treatment in newborns (68.8%), while endoscopic ventriculocisternostomy (EDV) was the preferred approach in infants (74.1%). Overall complication rate was 26.1% (57.6% for VPD and 4.1% for EDV). Hydrocephalus is the most common disease treated by paediatric neurosurgeons in Africa. Management is usually delayed, hence the importance of prevention, especially of neural tube defects and infections.

Planar single plane area determination is a viable substitute for total volumetry of CSF and brain in childhood hydrocephalus

BACKGROUND

In the treatment of childhood hydrocephalus, 3D volumetry seems to have many advantages over classical planar index measurements for dedicated monitoring of changes in cerebrospinal fluid and brain volume. Nevertheless, this method requires extensive technical effort and access to the complete three-dimensional data set. Against this background, we evaluated the possibility of planar area determination in a single plane and the correlation to volumetry.

METHODS

138 routinely performed true FISP MRI sequences (1 mm isovoxel) were analyzed retrospectively in 68 patients with pediatric hydrocephalus. After preprocessing, the 3D-data sets were skull stripped to estimate the inner skull volume. A 2-class segmentation into different tissue types (brain matter and CSF) was performed, and the volumes of CSF (VCSF) and brain matter (VBrain) were calculated. A plane at the level of the foramina of Monro was manually identified in the ac-pc oriented data. In this plane, the areas of brain (ABrain) and CSF (ACSF) in cm² were calculated and used for further correlation analysis.

RESULTS

Mean VCSF was 340 ± 145 cm³ and VBrain 1173 ± 254 cm³. In the selected plane, ACSF was 26 ± 14 cm², and ABrain was 107 ± 25 cm². There was a very strong positive correlation between both ACSF and VCSF (r = 0.895) and between ABrain and VBrain (r = 0.846). The prediction equations for VBrain and VCSF were highly significant.

CONCLUSION

Planar area determination of brain and CSF correlates excellently with both VCSF and VBrain. Thus, areas can serve as a surrogate marker for total brain and CSF volumes for a quantitated objective tracking of changes during treatment of childhood hydrocephalus.

Use of computed tomography and diffusion weighted imaging in children with ventricular shunt

PURPOSE

To evaluate the indications, number, and imaging results of brain computed tomography (CT) and diffusion weighted imaging (DWI) in children with ventriculoperitoneal shunt, to estimate the radiation dose, and to evaluate the effectiveness of DWI.

METHODS

This retrospectively study included 54 consecutive patients (boys/girls = 30/24, mean age, 3 ± 4.1 years) with shunt that were placed due to congenital abnormalities-hypoxic ischemic encephalopathy between January 2015 and March 2018. The presence of shunt-related complications (SRC) was assessed using clinical and neuroimaging findings, and the standard reference was accepted as the shunt revision. Size comparisons of ventricles were performed using Evans index and the frontal and occipital horn ratio, and each measurement made by the observers were compared using Bland-Altman analysis. A kappa coefficient and the intraclass correlation coefficient were calculated to assess the agreement between observers.

RESULTS

The mean number of hospital admission, number of CT scans, and DWI were 5.8, 4.8, and 1.1, respectively per patient. A significant linear correlation was observed between hospital admission and CT scans (r = 0.288, p = 0.035). The number of CT scans and the cumulative effective dose per patient were higher in patients with SRC than in those without (p < 0.001). The mortality rate due to radiation-induced neoplasia has increased by 0.33% in the study period. The inter-observer agreement was perfect or substantial for the catheter visualization, assessment of the ventricular system on DWI, and for the image quality of DWI between observers (κ = 0.704-1, p ≤ 0.001). No significant difference was found between CT and DWI in the measurements of Evans index and the frontal and occipital horn ratio (p > 0.05). Inter-observer agreements between observers were almost perfect for the Evans index and the frontal and occipital horn ratio (ICC = 0.94-0.99, p < 0.001).

CONCLUSIONS

An awareness of the use of CT in children is still inadequate and difficulties in the diagnosis of SRC probably cause the overuse of CT. DWI should be preferred in the diagnosis of SRC and the follow-up of patients. Otherwise, the increase in the prevalence of several diseases, particularly neoplasia, may be inevitable because of the over use of CT.

Accuracy of Intraoperative Computed Tomography in Deep Brain Stimulation-A Prospective Noninferiority Study

Introduction

Clinical response to deep brain stimulation (DBS) strongly depends on the appropriate placement of the electrode in the targeted structure. Postoperative MRI is recognized as the gold standard to verify the DBS‐electrode position in relation to the intended anatomical target. However, intraoperative computed tomography (iCT) might be a feasible alternative to MRI.

Materials and Methods

In this prospective noninferiority study, we compared iCT with postoperative MRI (24‐72 hours after surgery) in 29 consecutive patients undergoing placement of 58 DBS electrodes. The primary outcome was defined as the difference in Euclidean distance between lead tip coordinates as determined on both imaging modalities, using the lead tip depicted on MRI as reference. Secondary outcomes were difference in radial error and depth, as well as difference in accuracy relative to target.

Results

The mean difference between the lead tips was 0.98 ± 0.49 mm (0.97 ± 0.47 mm for the left‐sided electrodes and 1.00 ± 0.53 mm for the right‐sided electrodes). The upper confidence interval (95% CI, 0.851 to 1.112) did not exceed the noninferiority margin established. The average radial error between lead tips was 0.74 ± 0.48 mm and the average depth error was determined to be 0.53 ± 0.40 mm. The linear Deming regression indicated a good agreement between both imaging modalities regarding accuracy relative to target.

Conclusions

Intraoperative CT is noninferior to MRI for the verification of the DBS‐electrode position. CT and MRI have their specific benefits, but both should be considered equally suitable for assessing accuracy.

Detection of pediatric musculoskeletal pathology using the fluid-sensitive sequence

BACKGROUND

Musculoskeletal complaints are common among children, and magnetic resonance (MR) is increasingly used to supplement the clinical assessment. The validation of a short triage protocol could reduce the number of unnecessary contrast-enhanced MR studies that sometimes also require the need for sedation.

OBJECTIVE

To compare the diagnostic accuracy between fluid-sensitive sequence and contrast-enhanced MR study in the detection of musculoskeletal pathology in the pelvis and the appendicular skeleton in children older than 2 years.

MATERIALS AND METHODS

We performed a retrospective review between Feb. 1, 2016, and Oct. 31, 2016, and identified 99 studies from 96 patients (48 boys and 48 girls; mean age ± standard deviation, 11.1±4.6 years) without syndromic deformity, recent trauma, a history of infectious or inflammatory arthropathy, prior instrumentation or incomplete records. Two radiologists reviewed each study twice, at least 1 month apart, first using only the fluid-sensitive sequences (triage study) and later using the contrast-enhanced study. Readers rated the presence or absence of pathology independently and generated final impressions in consensus. We used Cohen's kappa (κ) and percentage agreement to compare agreement between readers and between studies, respectively.

RESULTS

Inter-reader agreement was overall higher for the contrast-enhanced studies (κ range = 0.91-1) than for the triage studies (κ range = 0.49-1). Percentage agreement between studies was high for the detection of pathology (97-100%) and for the impressions (93%). Clinical diagnoses were stress reaction or overuse in 31%, infection in 21%, space-occupying process in 17%, normal in 15%, inflammatory in 14%, and both inflammatory and overuse in 1%. The full study increased diagnostic confidence in five studies and accuracy in two but did not alter management.

CONCLUSION

The fluid-sensitive sequence had a near-perfect percentage of agreement with the contrast-enhanced study in the detection of musculoskeletal pathology and could possibly be used to screen children who need a contrast-enhanced MR study.

Value of MRI in medicine: More than just another test?

There is increasing scrutiny from healthcare organizations towards the utility and associated costs of imaging. MRI has traditionally been used as a high-end modality, and although shown extremely important for many types of clinical scenarios, it has been suggested as too expensive by some. This editorial will try and explain how value should be addressed and gives some insights and practical examples of how value of MRI can be increased. It requires a global effort to increase accessibility, value for money, and impact on patient management. We hope this editorial sheds some light and gives some indications of where the field may wish to address some of its research to proactively demonstrate the value of MRI. Level of Evidence: 5 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2019;49:e14-e25.

Contemporary management and surveillance strategy after shunt or endoscopic third ventriculostomy procedures for hydrocephalus

The management of hydrocephalus can be challenging even in expert hands. Due to acute presentation, recurrence, accompanying complications, the need for urgent diagnosis; a robust management plan is an absolute necessity. We devised a novel time efficient surveillance strategy during emergency, and clinic follow up settings which has never been described in the literature. We searched all articles embracing management/surveillance protocol on pediatric hydrocephalus utilizing the terms "hydrocephalus follow up" or "surveillance protocol after hydrocephalus treatment". The authors present their own strategy based on vast experience in the hydrocephalus management at a single institution. The need for the diagnostic laboratory testing, age and presentation based radiological imaging, significance of neuro-opthalmological exam, and when to consider the emergent exploration have been discussed in detail. Moreover, a definitive triaging strategy has been described with the help of flow chart diagrams for clinicians, and the neurosurgeons in practice. The triage starts from detail history, physical exam, necessary labs, radiological imaging depending on the presentation, and the age of the child. A quick head CT scan helps after shunt surgery while, a FAST sequence MRI scan (fsMRI) is important in post ETV patients. The need for neuro-opthalmological exam, and the shunt series stays vital in asymptomatic patients during regular follow up.

Imaging Strategies for Suspected Acute Cranial Shunt Failure: A Cost-Effectiveness Analysis

OBJECTIVES

We compared cost-effectiveness of cranial computed tomography (CT), fast sequence magnetic resonance imaging (fsMRI), and ultrasonography measurement of optic nerve sheath diameter (ONSD) for suspected acute shunt failure from the perspective of a health care organization.

METHODS

We modeled 4 diagnostic imaging strategies: (1) CT scan, (2) fsMRI, (3) screening ONSD by using point of care ultrasound (POCUS) first, combined with CT, and (4) screening ONSD by using POCUS first, combined with fsMRI. All patients received an initial plain radiographic shunt series (SS). Short- and long-term costs of radiation-induced cancer were assessed with a Markov model. Effectiveness was measured as quality-adjusted life-years. Utilities and inputs for clinical variables were obtained from published literature. Sensitivity analyses were performed to evaluate the effects of parameter uncertainty.

RESULTS

At a previous probability of shunt failure of 30%, a screening POCUS in patients with a normal SS was the most cost-effective. For children with abnormal SS or ONSD measurement, fsMRI was the preferred option over CT. Performing fsMRI on all patients would cost $269 770 to gain 1 additional quality-adjusted life-year compared with POCUS. An imaging pathway that involves CT alone was dominated by ONSD and fsMRI because it was more expensive and less effective.

CONCLUSIONS

In children with low pretest probability of cranial shunt failure, an ultrasonographic measurement of ONSD is the preferred initial screening test. fsMRI is the more cost-effective, definitive imaging test when compared with cranial CT.

SSh versus TSE sequence protocol in rapid MR examination of pediatric patients with programmable drainage system

PURPOSE

A low radiation burden is essential during diagnostic procedures in pediatric patients due to their high tissue sensitivity. Using MR examination instead of the routinely used CT reduces the radiation exposure and the risk of adverse stochastic effects. Our retrospective study evaluated the possibility of using ultrafast single-shot (SSh) sequences and turbo spin echo (TSE) sequences in rapid MR brain imaging in pediatric patients with hydrocephalus and a programmable ventriculoperitoneal drainage system.

METHODS

SSh sequences seem to be suitable for examining pediatric patients due to the speed of using this technique, but significant susceptibility artifacts due to the programmable drainage valve degrade the image quality. Therefore, a rapid MR examination protocol based on TSE sequences, less sensitive to artifacts due to ferromagnetic components, has been developed. Of 61 pediatric patients who were examined using MR and the SSh sequence protocol, a group of 15 patients with hydrocephalus and a programmable drainage system also underwent TSE sequence MR imaging. The susceptibility artifact volume in both rapid MR protocols was evaluated using a semiautomatic volumetry system.

RESULTS

A statistically significant decrease in the susceptibility artifact volume has been demonstrated in TSE sequence imaging in comparison with SSh sequences. Using TSE sequences reduced the influence of artifacts from the programmable valve, and the image quality in all cases was rated as excellent. In all patients, rapid MR examinations were performed without any need for intravenous sedation or general anesthesia.

CONCLUSIONS

Our study results strongly suggest the superiority of the TSE sequence MR protocol compared to the SSh sequence protocol in pediatric patients with a programmable ventriculoperitoneal drainage system due to a significant reduction of susceptibility artifact volume. Both rapid sequence MR protocols provide quick and satisfactory brain imaging with no ionizing radiation and a reduced need for intravenous or general anesthesia.

The Burden of Ionizing Radiation Studies in Children with Ventricular Shunts

OBJECTIVES

To quantify the number of shunt-related imaging studies that patients with ventricular shunts undergo and to calculate the proportion of computed tomography (CT) scans associated with a surgical intervention.

STUDY DESIGN

Retrospective longitudinal cohort analysis of patients up to age 22 years with a shunt placed January 2002 through December 2003 at a pediatric hospital. Primary outcome was the number of head CT scans, shunt series radiograph, skull radiographs, nuclear medicine, and brain magnetic resonance imaging studies for 10 years following shunt placement. Secondary outcome was surgical interventions performed within 7 days of a head CT. Descriptive statistics were used for analysis.

RESULTS

Patients (n = 130) followed over 10 years comprised the study cohort. The most common reasons for shunt placement were congenital hydrocephalus (30%), obstructive hydrocephalus (19%), and atraumatic hemorrhage (18%), and 97% of shunts were ventriculoperitoneal. Patients underwent a median of 8.5 head CTs, 3.0 shunt series radiographs, 1.0 skull radiographs, 0 nuclear medicine studies, and 1.0 brain magnetic resonance imaging scans over the 10 years following shunt placement. The frequency of head CT scans was greatest in the first year after shunt placement (median 2.0 CTs). Of 1411 head CTs in the cohort, 237 resulted in surgical intervention within 7 days (17%, 95% CI 15%-19%).

CONCLUSIONS

Children with ventricular shunts have been exposed to large numbers of imaging studies that deliver radiation and most do not result in a surgical procedure. This suggests a need to improve the process of evaluating for ventricular shunt malfunction and minimize radiation exposure.

Medical conditions associated with the use of CT in children and young adults, Great Britain, 1995-2008

OBJECTIVE

To describe the medical conditions associated with the use of CT in children or young adults with no previous cancer diagnosis.

METHODS

Radiologist reports for scans performed in 1995-2008 in non-cancer patients less than 22 years of age were collected from the radiology information system in 44 hospitals of Great Britain. By semantic search, an automated procedure identified 185 medical conditions within the radiologist reports. Manual validation of a subsample by a paediatric radiologist showed a satisfactory performance of the automatic coding procedure.

RESULTS

Medical information was extracted for 37,807 scans; 19.5% scans were performed in children less than 5 years old; 52.0% scans were performed in 2000 or after. Trauma, diseases of the nervous (mainly hydrocephalus) or the circulatory system were each mentioned in 25-30% of scans. Hydrocephalus was mentioned in 19% of all scans, 59% of scans repeated ≥5 times in a year, and was the most frequent condition in children less than 5 years of age. Congenital diseases/malformations, disorders of the musculoskeletal system/connective tissues and infectious or respiratory diseases were each mentioned in 5-10% of scans. Suspicionor diagnosis of benign or malignant tumour was identified in 5% of scans.

CONCLUSION

This study describes the medical conditions that likely underlie the use of CT in children in Great Britain. It shows that patients with hydrocephalus may receive high cumulative radiation exposures from CT in early life, i.e. at ages when they are most sensitive to radiation. Advances in knowledge: The majority of scans were unrelated to cancer suspicion. Repeated scans over time were mainly associated with the management of hydrocephalus.

Patients exposed to diagnostic head and neck radiation for the management of shunted hydrocephalus have a significant risk of developing thyroid nodules

PURPOSE

External radiation to the head and neck can lead to an increased incidence of thyroid nodules. We investigated whether patients requiring repeated head and neck imaging for the management of shunted hydrocephalus had a higher incidence of ultrasound-detected thyroid nodules compared to reports of comparable age.

METHODS

Patients treated at our institution for shunted hydrocephalus from 1990 to 2003 were contacted. Enroled patients underwent a thyroid ultrasound. Demographic data and radiation exposure history were obtained retrospectively.

RESULTS

Thyroid nodules were identified sonographically in 15/112 patients (13.6 %). Patients with thyroid nodules were older (mean 24.3 ± 7.6 years) than those without (mean 18.4 ± 8.0 years) (p = 0.005). Those with a detectable thyroid nodule had a longer follow up time compared to those who did not (mean 21.9 ± 5.5 vs. 15.1 ± 7 years, respectively) (p = 0.018).

CONCLUSION

Patients with shunted hydrocephalus are exposed to substantial head and neck radiation from diagnostic imaging and have a higher incidence of thyroid nodules detected by ultrasonography. These patients should be provided ongoing surveillance for detection of thyroid nodules and the possibility of malignancy.

How to Reduce Head CT Orders in Children with Hydrocephalus Using the Lean Six Sigma Methodology: Experience at a Major Quaternary Care Academic Children's Center

BACKGROUND AND PURPOSE

Lean Six Sigma methodology is increasingly used to drive improvement in patient safety, quality of care, and cost-effectiveness throughout the US health care delivery system. To demonstrate our value as specialists, radiologists can combine lean methodologies along with imaging expertise to optimize imaging elements-of-care pathways. In this article, we describe a Lean Six Sigma project with the goal of reducing the relative use of pediatric head CTs in our population of patients with hydrocephalus by 50% within 6 months.

MATERIALS AND METHODS

We applied a Lean Six Sigma methodology using a multidisciplinary team at a quaternary care academic children's center. The existing baseline imaging practice for hydrocephalus was outlined in a Kaizen session, and potential interventions were discussed. An improved radiation-free workflow with ultrafast MR imaging was created. Baseline data were collected for 3 months by using the departmental radiology information system. Data collection continued postintervention and during the control phase (each for 3 months). The percentage of neuroimaging per technique (head CT, head ultrasound, ultrafast brain MR imaging, and routine brain MR imaging) was recorded during each phase.

RESULTS

The improved workflow resulted in a 75% relative reduction in the percentage of hydrocephalus imaging performed by CT between the pre- and postintervention/control phases (Z-test, P = .0001).

CONCLUSIONS

Our lean interventions in the pediatric hydrocephalus care pathway resulted in a significant reduction in head CT orders and increased use of ultrafast brain MR imaging.

Strategies for Computed Tomography Radiation Dose Reduction in Pediatric Neuroimaging

BACKGROUND

Radiation exposure from diagnostic imaging is a significant concern, particularly in the care of pediatric patients. Computed tomography (CT) scanning is a significant source of radiation.

OBJECTIVE

To demonstrate that diagnostic quality CT images can be obtained while minimizing the effective radiation dose to the patient.

METHODS

In this retrospective cross-sectional study, noncontrast head CT scan data were reviewed, and indications for scans and estimated radiation dose delivered were recorded. The estimated effective radiation dose (EERD) for each CT protocol was reviewed.

RESULTS

We identified 251 head CT scans in a single month. Of these, 96 scans were using a low-dose shunt protocol with a mean EERD of 0.82 mSv. The remaining 155 scans were performed using the standard protocol, and the mean EERD was 1.65 mSv. Overall, the EERD was minimized while maintaining diagnostic scan quality.

CONCLUSION

Although replacing a CT with magnetic resonance imaging is ideal to completely avoid ionizing radiation, this is not always practical or preferred. Therefore, it is important to have CT protocols in place that minimize radiation dose without sacrificing diagnostic quality. The protocols in place at our institution could be replicated at other academic and community hospitals and imaging centers.

Minimizing Radiation Exposure in Evaluation of Pediatric Head Trauma: Use of Rapid MR Imaging

BACKGROUND AND PURPOSE

With >473,000 annual emergency department visits for children with traumatic brain injuries in the United States, the risk of ionizing radiation exposure during CT examinations is a real concern. The purpose of this study was to assess the validity of rapid MR imaging to replace CT in the follow-up imaging of patients with head trauma.

MATERIALS AND METHODS

A retrospective review of 103 pediatric patients who underwent initial head CT and subsequent follow-up rapid MR imaging between January 2010 and July 2013 was performed. Patients had minor head injuries (Glasgow Coma Scale, >13) that required imaging. Initial head CT was performed, with follow-up rapid MR imaging completed within 48 hours. A board-certified neuroradiologist, blinded to patient information and scan parameters, then independently interpreted the randomized cases.

RESULTS

There was almost perfect agreement in the ability to detect extra-axial hemorrhage on rapid MR imaging and CT (κ = 0.84, P < .001). Evaluation of hemorrhagic contusion/intraparenchymal hemorrhage demonstrated a moderate level of agreement between MR imaging and CT (κ = 0.61, P < .001). The ability of MR imaging to detect a skull fracture also showed a substantial level of agreement with CT (κ = 0.71, P < .001). Detection of diffuse axonal injury demonstrated a slight level of agreement between MR imaging and CT (κ = 0.154, P = .04). However, the overall predictive agreement for the detection of an axonal injury was 91%.

CONCLUSIONS

Rapid MR imaging is a valid technique for detecting traumatic cranial injuries and an adequate examination for follow-up imaging in lieu of repeat CT.

Magnetic resonance imaging acquisition techniques intended to decrease movement artefact in paediatric brain imaging: a systematic review

Attaining paediatric brain images of diagnostic quality can be difficult because of young age or neurological impairment. The use of anaesthesia to reduce movement in MRI increases clinical risk and cost, while CT, though faster, exposes children to potentially harmful ionising radiation. MRI acquisition techniques that aim to decrease movement artefact may allow diagnostic paediatric brain imaging without sedation or anaesthesia. We conducted a systematic review to establish the evidence base for ultra-fast sequences and sequences using oversampling of k-space in paediatric brain MR imaging. Techniques were assessed for imaging time, occurrence of movement artefact, the need for sedation, and either image quality or diagnostic accuracy. We identified 24 relevant studies. We found that ultra-fast techniques had shorter imaging acquisition times compared to standard MRI. Techniques using oversampling of k-space required equal or longer imaging times than standard MRI. Both ultra-fast sequences and those using oversampling of k-space reduced movement artefact compared with standard MRI in unsedated children. Assessment of overall diagnostic accuracy was difficult because of the heterogeneous patient populations, imaging indications, and reporting methods of the studies. In children with shunt-treated hydrocephalus there is evidence that ultra-fast MRI is sufficient for the assessment of ventricular size.

Radiographic evaluation of pediatric cerebrospinal fluid shunt malfunction in the emergency setting

Children with ventricular cerebrospinal fluid shunts for treatment of hydrocephalus require frequent evaluation for potential shunt malfunction. Current practice relies heavily on neuroimaging, particularly cranial computed tomography, which repeatedly exposes children to ionizing radiation. Rapid cranial magnetic resonance imaging is a new radiation-sparing alternative to CT for evaluation of potential shunt malfunction. We review the diagnostic test performance, radiation exposure, advantages, and limitations of the major neuroimaging modalities available to providers caring for children with possible shunt malfunction in the emergent setting.

Magnetic resonance imaging as an alternative to computed tomography in select patients with traumatic brain injury: a retrospective comparison

OBJECT

Traumatic head injury (THI) is a highly prevalent condition in the United States, and concern regarding excess radiation-related cancer mortality has placed focus on limiting the use of CT in the evaluation of pediatric patients with THI. Given the success of rapid-acquisition MRI in the evaluation of ventriculoperitoneal shunt malfunction in pediatric patient populations, this study sought to evaluate the sensitivity of MRI in the setting of acute THI.

METHODS

Medical records of 574 pediatric admissions for THI to a Level 1 trauma center over a 10-year period were retrospectively reviewed to identify patients who underwent both CT and MRI examinations of the head within a 5-day period. Thirty-five patients were found, and diagnostic images were available for 30 patients. De-identified images were reviewed by a neuroradiologist for presence of any injury, intracranial hemorrhage, diffuse axonal injury (DAI), and skull fracture. Radiology reports were used to calculate interrater reliability scores. Baseline demographics and concordance analysis was performed with Stata version 13.

RESULTS

The mean age of the 30-patient cohort was 8.5 ± 6.7 years, and 63.3% were male. The mean Injury Severity Score was 13.7 ± 9.2, and the mean Glasgow Coma Scale score was 9 ± 5.7. Radiology reports noted 150 abnormal findings. CT scanning missed findings in 12 patients; the missed findings included DAI (n = 5), subarachnoid hemorrhage (n = 6), small subdural hematomas (n = 6), cerebral contusions (n = 3), and an encephalocele. The CT scan was negative in 3 patients whose subsequent MRI revealed findings. MRI missed findings in 13 patients; missed findings included skull fracture (n = 5), small subdural hematomas (n = 4), cerebral contusions (n = 3), subarachnoid hemorrhage (n = 3), and DAI (n = 1). MRI was negative in 1 patient whose preceding CT scan was read as positive for injury. Although MRI more frequently reported intracranial findings than CT scanning, there was no statistically significant difference between CT and MRI in the detection of any intracranial injury (p = 0.63), DAI (p = 0.22), or intracranial hemorrhage (p = 0.25). CT scanning tended to more frequently identify skull fractures than MRI (p = 0.06).

CONCLUSIONS

MRI may be as sensitive as CT scanning in the detection of THI, DAI, and intracranial hemorrhage, but missed skull fractures in 5 of 13 patients. MRI may be a useful alternative to CT scanning in select stable patients with mild THI who warrant neuroimaging by clinical decision rules.

Test characteristics of quick brain MRI for shunt evaluation in children: an alternative modality to avoid radiation

OBJECT

Quick brain magnetic resonance imaging (QB-MRI) is a rapid, radiation-free technique to detect life-threatening CSF shunt malfunction. QB-MRI has not been widely studied or adopted. The primary objective of this study was to evaluate the test characteristics of QB-MRI for detecting shunt malfunction. Test characteristics of brain computed tomography (CT) and QB-MRI were then compared. Secondary objectives included comparison of time to study completion and use of sedatives for both modalities, as well as comparison of time to study completion for QB-MRI before and after implementation of a Pediatric Emergency Department (PED) shunt clinical pathway.

METHODS

A retrospective chart review was performed at 2 tertiary care hospital PEDs. The authors reviewed the charts of children who underwent QB-MRI or CT for suspected shunt malfunction between July 2008 and June 2012. They also reviewed the patients' neuroradiology reports and classified ventricular size as positive (enlarged) or negative (normal, smaller, or unchanged). Shunt malfunction was defined by surgical revision within 30 days.

RESULTS

Nine hundred ninety-seven PED visits (involving 724 QB-MRIs and 273 CTs) were included. Surgical revision was performed in 235 cases (23.6%). For QB-MRI, sensitivity was 58.5% (95% CI 51.1%-65.6%) and specificity was 93.3% (90.8%-95.3%). For CT, sensitivity was 53.2% (95% CI 38.1%-67.9%) and specificity was 95.6% (92%-97.9%). The mean time to completion of QB-MRI was 115 minutes versus 83 minutes for CT (difference 32 minutes, 95% CI, 22-42 minutes, p < 0.001). The mean time from presentation to completion of QB-MRI prior to application of the CSF shunt pathway was 132 minutes versus 112 minutes after application of the CSF shunt pathway (difference 20 minutes, 95% CI 5-35 minutes, p = 0.01). Anxiolytic medications were used in 3.7% of CT studies and 4.4% of QB-MRI studies (p = 0.74).

CONCLUSIONS

QB-MRI and CT have similar test characteristics for detecting CSF shunt malfunction in children and similar requirements for sedation. The longer interval from order placement to imaging completion for QB-MRI is arguably justified by reduction of radiation exposure in this population subject to frequent brain imaging.

Hydrocephalus in children less than 1 year of age in northern Mozambique

Background:

In developed countries, the incidence of neonatal hydrocephalus ranges from 3 to 5 cases per 1000 live births, but little is known about the frequency of hydrocephalus in Africa. In Mozambique, there is no primary information related to this disorder, but using the above data, the expected incidence of neonatal hydrocephalus would range from 2900 to 4800 cases per year.

Methods:

This study is based on 122 children younger than 1 year with neonatal hydrocephalus, followed up between January 2010 and December 2012, their origin and treatment, and aims to evaluate difficulties with diagnosis, treatment, and follow-up in northern Mozambique.

Results:

Identified cases were mainly less than 6 months old (77%), with severe macrocephaly and the classic stigmata of this condition. A high rate of follow-up loss (44.3%) was detected, particularly among children from more distant locations. Our findings contrast with the expected 1000-1700 cases that would occur in the area during the study period, being considerably lower.

Conclusions:

Hydrocephalus is a serious problem in sub-Saharan Africa, whose effects can be minimized by a better organization of the health system in hydrocephalus prevention, referral, and follow-up. New management alternatives to provide treatment to more children with this disorder and reduction of the follow-up difficulties caused due to geographical reasons for the children undergoing treatment are essential.

Pilot study of radiation dose reduction for pediatric head CT in evaluation of ventricular size

BACKGROUND AND PURPOSE

CT is a ubiquitous, efficient, and cost-effective method to evaluate pediatric ventricular size, particularly in patients with CSF shunt diversion who often need emergent imaging. We therefore sought to determine the minimum dose output or CT dose index required to produce clinically acceptable examinations.

MATERIALS AND METHODS

Using a validated noise insertion method and CT projection data from 22 patients, standard pediatric head CT images were reconstructed with weighted filtered back-projection and sinogram-affirmed iterative reconstruction corresponding to routine, 25%, and 10% dose. Reconstructed images were then evaluated by 3 neuroradiologists (blinded to dose and reconstruction method) for ventricular size, diagnostic confidence, image quality, evidence of hemorrhage, and shunt tip location, and compared with the reference standard.

RESULTS

There was no significant difference in the ventricular size ranking, and the sensitivity for moderate to severe hydrocephalus was 100%. There was no significant difference between the full-dose level and the ventricular size rankings at the 25% or the 10% dose level for either reconstruction kernel (P > .979). Diagnostic confidence was maintained across doses and kernel. Hemorrhage was more difficult to identify as image quality degraded as dose decreased but was still seen in a majority of cases. Shunts were identified by all readers across all doses and reconstruction methods.

CONCLUSIONS

CT images having dose reductions of 90% relative to routine head CT examinations provide acceptable image quality to address the specific clinical task of evaluating ventricular size.

Comparison of rapid cranial MRI to CT for ventricular shunt malfunction

OBJECTIVES

To compare the accuracy of rapid cranial magnetic resonance imaging (MRI) with that of computed tomography (CT) for diagnosing ventricular shunt malfunction.

METHODS

We performed a single-center, retrospective cohort study of children ≤21 years of age who underwent either rapid cranial MRI or cranial CT in the emergency department (ED) for evaluation of possible ventricular shunt malfunction. Each neuroimaging study was classified as "normal" (unchanged or decreased ventricle size) or "abnormal" (increased ventricle size). We classified a patient as having a ventricular shunt malfunction if operative revision for relief of mechanical causes of altered shunt flow was needed within 72 hours of initial ED evaluation. Our primary analysis tested noninferiority of the accuracy of rapid cranial MRI to CT for diagnosing shunt malfunction (noninferiority margin 10%).

RESULTS

We included 698 ED visits for 286 unique patients, with a median age at visit of 10.0 years (interquartile range 5.9-15.5 years). Patients underwent CT in 336 (48%) or rapid cranial MRI in 362 (52%) of ED visits for evaluation of possible shunt malfunction. Patients had operative revision for ventricular shunt malfunction in 140 ED visits (20%). The accuracy of rapid cranial MRI was not inferior to that of CT scan for diagnosing ventricular shunt malfunction (81.8% MRI vs 82.4% CT; risk difference 2.0%; 95% confidence interval, -4.2% to 8.2%).

CONCLUSIONS

Rapid cranial MRI was not inferior to CT for diagnosing ventricular shunt malfunction and offers the advantage of sparing a child ionizing radiation exposure.

Results of a North American survey of rapid-sequence MRI utilization to evaluate cerebral ventricles in children

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.

Techniques that decrease or eliminate ionizing radiation for evaluation of ventricular shunts in children with hydrocephalus

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 so as to decrease the chance of the deleterious effects from occurring. The article outlines the epidemiology of ventricular shunt catheters, the typical indications and methods for shunt evaluation, and the preferred alternative imaging methods that eliminate or reduce radiation exposure.