Diagnostic Excellence in Pediatric Spine Imaging: Using Contextualized Imaging Protocols

Contextual design and selection of MRI protocols is critical for making an accurate diagnosis given the wide variety of clinical indications for spine imaging in children. Here, we describe our pediatric spine imaging protocols in detail, tailored to specific clinical questions.

Role of Electroencephalogram (EEG) and Magnetic Resonance Imaging (MRI) Findings in Early Recognition and Diagnosis of Neuronal Ceroid Lipofuscinosis Type 2 Disease

Neuronal ceroid lipofuscinosis type 2 (CLN2) disease is a very rare neurodegenerative lysosomal storage disorder. Progression is rapid and irreversible, making early diagnosis crucial for timely treatment. A group of pediatric neurologists and neuroradiologists with expertise in CLN2 convened to discuss early electroencephalogram (EEG) and magnetic resonance imaging (MRI) findings in CLN2 diagnosis. Of 18 CLN2 cases, 16 (88.9%) had background slowing and 16 (88.9%) had epileptiform discharges on initial EEG. Seven of 17 (41.2%) patients who received intermittent low-frequency photic stimulation had a photoparoxysmal response. Initial MRIs showed subtle cerebellar (n = 14, 77.8%) or cerebral (n = 9, 50.0%) atrophy, white matter abnormalities (n = 11, 61.1%), and basal ganglia T2 hypointensity (n = 6, 33.3%), which became more apparent on follow-up MRI. The recognition of even subtle cerebellar atrophy and white matter signal changes in children aged 2-5 years who present with language delay, new-onset seizures, and an EEG with epileptiform discharges and background slowing should prompt investigation for CLN2. Because these early signs are not unique to CLN2, genetic testing is essential early in the diagnostic journey.

Ventriculomegaly thresholds for prediction of symptomatic post-hemorrhagic ventricular dilatation in preterm infants

BACKGROUND

Benefits from early surgical intervention in preterm infants with intraventricular hemorrhage (IVH) prior to symptomatic ventriculomegaly must be weighed against risks of surgery. We calculated thresholds of common ventriculomegaly indices at a late-intervention institution to predict subsequent symptomatic ventriculomegaly requiring neurosurgery.

METHODS

We retrospectively reviewed neuroimaging and neurosurgical outcomes in preterm infants with grade III/IV IVH between 2007 and 2020. Frontal-occipital horn ratio (FOHR), frontal-temporal horn ratio (FTHR), anterior horn width (AHW), and ventricular index (VI) were measured. Area under the receiver operating curve (AUC) for predicting intervention (initiated after progressive symptomatic ventriculomegaly) was calculated for diagnostic scan, scans during weeks 1-4, and maximum measurement prior to intervention. Threshold values that optimized sensitivity and specificity were derived.

RESULTS

A total of 1254 scans in 132 patients were measured. In all, 37 patients had a neurosurgical intervention. All indices differed between those with and without intervention from the first diagnostic scan (p < 0.001). AUC of maximum measurement was 97.1% (95% CI 94.6-99.7) for FOHR, 97.7% (95% CI 95.6-99.8) for FTHR, 96.6% (95% CI 93.9-99.4) for AHW, and 96.8% (95% CI 94.0-99.5) for VI. Calculated thresholds were FOHR 0.66, FTHR 0.62, AHW 15.5 mm, and VI 8.4 mm > p97 (sensitivities >86.8%, specificities >90.1%).

CONCLUSION

Ventriculomegaly indices were greater for patients who developed progressive persistent ventriculomegaly from the first diagnostic scan and predicted neurosurgical intervention.

IMPACT

We derived thresholds of common ventriculomegaly indices (ventricular index, anterior frontal horn width, fronto-occipital horn and fronto-temporal horn index) to best predict the development of progressive symptomatic post-hemorrhage hydrocephalus in preterm infants with intraventricular hemorrhage. While current thresholds were established by a priori expert consensus, we report the first data-driven derivation of ventriculomegaly thresholds across all indices for the prediction of symptomatic hydrocephalus. Data-derived thresholds will more precisely weigh the risks and benefits of early intervention.

ACR Appropriateness Criteria® Cerebrovascular Disease-Child

Stroke is an uncommon but an important and under-recognized cause of morbidity and mortality in children. Strokes may be due to either brain ischemia or intracranial hemorrhage. Common symptoms of pediatric acute stroke include headache, vomiting, focal weakness, numbness, visual disturbance, seizures, and altered consciousness. Most children presenting with an acute neurologic deficit do not have an acute stroke, but have symptoms due to stroke mimics which include complicated migraine, seizures with postictal paralysis, and Bell palsy. Because of frequency of stroke mimics, in children and the common lack of specificity in symptoms, the diagnosis of a true stroke may be delayed. There are a relatively large number of potential causes of stroke mimic and true stroke. Consequently, imaging plays a critical role in the assessment of children with possible stroke and especially in children who present with acute onset of stroke symptoms. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Subependymal Giant Cell Astrocytoma Size Measurement in Tuberous Sclerosis Complex: Noncontrast vs Contrast-Enhanced 3-Dimensional T1-Weighted Magnetic Resonance Imaging (MRI)

PURPOSE

Tuberous sclerosis complex is a multisystem genetic disorder characterized by multiorgan hamartomas, seizures, and developmental delay. Current consensus recommendations for tuberous sclerosis complex include brain magnetic resonance imaging (MRI) without and with contrast every 1 to 3 years until age 25 years for subependymal giant cell astrocytoma screening, and more often in patients with known subependymal giant cell astrocytoma. Recent reports in the literature regarding gadolinium deposition have prompted us to investigate the added value of intravenous contrast in this setting.

MATERIALS AND METHODS

Thirty-nine MRI examinations from 12 tuberous sclerosis complex patients with known subependymal giant cell astrocytoma were retrospectively reviewed for all caudothalamic groove lesions larger than 1 cm. Lesions were measured in 2 planes on both noncontrast and contrast-enhanced axial 3-dimensional (3D) T1-weighted imaging in a randomized fashion by 2 attending pediatric neuroradiologists. Differences in lesion measurements were compared to zero using a 1-sample t test.

RESULTS

On average, radiologist A measured lesions 1.1 mm larger in long-axis diameter without contrast (P = .0003), whereas radiologist B measured lesions 0.1 mm larger without contrast (not significant). Differences in lesion measurement were smaller when comparing noncontrast to contrast-enhanced 3D T1-weighted imaging than when comparing radiologist A to radiologist B.

CONCLUSIONS

Noncontrast axial 3D T1-weighted imaging is similar to contrast-enhanced axial 3D T1-weighted imaging for subependymal giant cell astrocytoma size measurement. It has high accuracy and may be a safer and more efficient imaging method for tuberous sclerosis complex patients who commonly undergo numerous MRI examinations throughout their lifetime. Further studies may be appropriate to determine whether contrast material could be beneficial in certain situations.

Correction to: A consensus response on the complete picture: reply to Lynøe and Eriksson

The original version on this paper contained an error. The COI statement is incorrectly presented.

Consensus statement on abusive head trauma in infants and young children

Abusive head trauma (AHT) is the leading cause of fatal head injuries in children younger than 2 years. A multidisciplinary team bases this diagnosis on history, physical examination, imaging and laboratory findings. Because the etiology of the injury is multifactorial (shaking, shaking and impact, impact, etc.) the current best and inclusive term is AHT. There is no controversy concerning the medical validity of the existence of AHT, with multiple components including subdural hematoma, intracranial and spinal changes, complex retinal hemorrhages, and rib and other fractures that are inconsistent with the provided mechanism of trauma. The workup must exclude medical diseases that can mimic AHT. However, the courtroom has become a forum for speculative theories that cannot be reconciled with generally accepted medical literature. There is no reliable medical evidence that the following processes are causative in the constellation of injuries of AHT: cerebral sinovenous thrombosis, hypoxic-ischemic injury, lumbar puncture or dysphagic choking/vomiting. There is no substantiation, at a time remote from birth, that an asymptomatic birth-related subdural hemorrhage can result in rebleeding and sudden collapse. Further, a diagnosis of AHT is a medical conclusion, not a legal determination of the intent of the perpetrator or a diagnosis of murder. We hope that this consensus document reduces confusion by recommending to judges and jurors the tools necessary to distinguish genuine evidence-based opinions of the relevant medical community from legal arguments or etiological speculations that are unwarranted by the clinical findings, medical evidence and evidence-based literature.

Differences in Activation and Deactivation in Children with Sickle Cell Disease Compared with Demographically Matched Controls

BACKGROUND AND PURPOSE

Declines in both functional activation and functional connectivity have been reported in patients with sickle cell disease. In this study, we derived the functional and default mode responses to a word stem paradigm in age-, ethnicity-, and background-matched subjects with sickle cell disease and control groups, with the aim of testing whether both networks were similarly attenuated and whether the changes were related to physiologic parameters that characterize sickle cell disease.

MATERIALS AND METHODS

Both the functional and default mode responses were obtained from age- and background-matched controls and the sickle cell population by using a visually presented word stem paradigm on a 3T scanner.

RESULTS

We observed an attenuated response to both activation and deactivation in the sickle cell disease group. There were no significant differences in the activation response between the 2 groups for the contrast control > sickle cell disease; however, significant differences were observed in the medial parietal cortex, the auditory cortex, and the angular gyrus for the default mode. For the sickle cell group, a significant correlation between the activation z scores and the physiologic parameters was observed; for the deactivation, the results were not significant but the trend was similar.

CONCLUSIONS

The results indicate that the physiologic parameters modulate the activation in the expected fashion, but that the effect was weaker for deactivation. Given that significant differences between the 2 groups were only seen for deactivation, additional factors must modulate the deactivation in sickle cell disease.

Acquired pathology of the pediatric spine and spinal cord

Pediatric spine pathology poses a diagnostic challenge for radiologists. Acquired spine pathology often yields nonspecific signs and symptoms in children, especially in the younger age groups, and diagnostic delay can carry significant morbidity. This review is focused on some of the more common diagnostic dilemmas we face when attempting to evaluate and diagnose acquired pediatric spine anomalies in daily practice. An understanding of some of the key differentiating features of these disease processes in conjunction with pertinent history, physical exam, and advanced imaging techniques can indicate the correct diagnosis.

Drop metastases to the pediatric spine revealed with diffusion-weighted MR imaging

Identifying drop metastases to the spine from pediatric brain tumors is crucial to treatment and prognosis. MRI is currently the gold standard for identifying drop metastases, more sensitive than CSF cytology, but imaging is not uncommonly inconclusive. Although diffusion-weighted imaging (DWI) of the brain is very useful in the evaluation of hypercellular tumors, DWI of the spine has not been clinically useful in children because of susceptibility artifacts and lack of spatial resolution. A new technique, readout-segmented echo planar imaging (EPI), has improved these images, allowing for identification of hypercellular drop metastases. We report a case that illustrates the utility of spine DWI in the detection of metastatic disease in children with primary central nervous system (CNS) tumors. This case suggests that DWI of the spine with readout-segmented EPI should be included in the evaluation for drop metastases.

The pediatric radiologist in private practice

Pediatric radiologists in private practice compose a significant group in our subspecialty. Specific issues relating to practicing pediatric radiology in the private setting will be discussed. Private and academic pediatric radiologists can together more effectively address the issues facing our subspecialty.

Regionally specific cortical thinning in children with sickle cell disease

Sickle cell disease (SCD) is a chronic disease with a significant rate of neurological complications in the first decade of life. In this retrospective study, cortical thickness was examined in children with SCD who had no detectable abnormalities on conventional magnetic resonance imaging/magnetic resonance angiography. Regional differences in cortical thickness from SCD were explored using age-matched healthy controls as comparison. A comparison analysis was done for SCD (n = 28) and controls (n = 29) based on age (5-11; 12-21 years), due to the age-dependent variation in cortex maturation. Distinct regions of thinning were found in SCD patients in both age groups. The number, spatial extent, and significance (P < 0.001) of these areas of thinning were increased in the older SCD group. Regions of interest (ROIs) were defined on the areas of highly significant thinning in the older group and then mapped onto the younger cohort; a multiparametric linear regression analysis of the ROI data demonstrated significant (P < 0.001) cortical thinning in SCD subjects, with the largest regions of thinning in the precuneus and the posterior cingulate. The regionally specific differences suggest that cortical thickness may serve as a marker for silent insults in SCD and hence may be a useful tool for identifying SCD patients at risk for neurological sequelae.

Low-dose nonenhanced head CT protocol for follow-up evaluation of children with ventriculoperitoneal shunt: reduction of radiation and effect on image quality

BACKGROUND AND PURPOSE

Children with a shunt for hydrocephalus often undergo multiple follow-up head CT scans, increasing the risk for long-term effects of ionizing radiation. The purpose of our study was to evaluate if an unenhanced low-dose head CT could consistently provide acceptable image quality and diagnostic information.

MATERIALS AND METHODS

Ninety-two children (mean age, 9 years; range, 8 months to 21 years; 45 boys and 47 girls) with a shunt for hydrocephalus and no clinical evidence of shunt malfunction who were referred for a follow-up nonenhanced head CT were included in the study. All studies were performed on a 4-section multidetector CT. Two CT studies were selected retrospectively for each patient, 1 performed at standard dose (220 mA) and 1 at low dose (80 mAs). Two radiologists independently evaluated and graded both standard-dose and low-dose studies for various image quality parameters. Attenuation and noise levels were measured, and gray-white differentiation and contrast-to-noise ratio (CNR) were calculated.

RESULTS

Low-dose CT resulted in 63% mean dose reduction. All low-dose CT scans were diagnostically acceptable. Image quality parameters were significantly lower at low dose (P = .0001) except for the parameters for streak artifacts (P = .46) and need for further imaging (P = .47), which were higher. Mean noise levels were significantly higher (P = .001) in low-dose studies, whereas CNR was significantly higher in standard dose CT (P = .001). A moderate to perfect agreement was noted between the 2 readers with regard to image quality assessment (65%-99%).

CONCLUSION

Low-dose nonenhanced head CT consistently provides diagnostically acceptable images with relevant diagnostic information in children with VP shunts resulting in substantial dose savings.

Surgical treatment of epilepsy in children caused by focal cortical dysplasia

Focal cortical dysplasia (FCD) is a congenital disorder of neuronal migration that is increasingly recognized as a common cause of seizures in children, occurring in 20-30% of all surgically treated cases of epilepsy in the pediatric population. Advances in neuroimaging have contributed to recognition of FCD. We report 15 children (9 female, 6 male) with FCD and surgically treated intractable epilepsy. In 9 cases, a surgical strategy of anatomic (frameless stereotactic) grid placement and physiologic (electrocorticography) resection was employed. Postoperative MRI scans were obtained, the pathologic specimen was graded according to the Brannstrom system, and seizure outcome was defined using the Engel classification. There were no deaths and no permanent morbidity. After, on average, 4 years since treatment, 10 children are seizure free, 2 are 2A, 2 are 2B and 1 is 3A. Predictors of good outcome are an MRI-defined lesion and increased cortical disorganization (higher Brannstrom grade). Subtotal resection did not preclude a seizure-free outcome.

MRI of the Neonatal Brain:Optimization of Spin-Echo Parameters

OBJECTIVE

Our aim was to measure the relaxation times of the neonatal brain and to use these to derive pulse sequence parameters that enhance the signal-to-noise ratio (SNR) and contrast of MRI scans of the neonatal brain.

SUBJECTS AND METHODS

The transverse (T2) and longitudinal (T1) relaxation times were measured for 10 healthy neonates, and the average relaxation times were calculated for both gray and white matter. Simulations using these values were then performed to estimate the optimal pulse sequence parameters. Images were obtained in three neonates using both the optimized and conventional sequence parameters.

RESULTS

The measured (mean +/- SD) relaxation times of the neonatal brain at 1.5 T were T1 equals 1712 +/- 235 msec and T2 equals 394 +/- 52 msec in white matter and T1 equals 1144 +/- 245 msec and T2 equals 206 +/- 26 msec in gray matter. The optimized T1-weighted imaging used a turbo spin-echo sequence with an echo-train length of 3 and TR/TE of 850/11 msec and showed increases in both the contrast and the SNR. The optimized T2-weighted sequence used a TE of 270 msec and markedly increased the contrast but at the expense of a reduction in the SNR.

CONCLUSION

Parameters of MRI turbo spin-echo sequences for scanning neonates are different from those required for adult studies, and appropriate protocols should be used.

The evolution of the apparent diffusion coefficient in the pediatric brain at low and high diffusion weightings

PURPOSE

To evaluate the evolution of the apparent diffusion coefficient (ADC) with age for different degrees of diffusion weighting using a clinically feasible approach.

MATERIALS AND METHODS

Data was acquired using separate scans with b values in the range typically used for clinical studies (100-900 seconds/mm(2)) and higher b values (1800-3000 seconds/mm(2)). The ADC was calculated for each of the data sets by fitting the data to a monoexponential function.

RESULTS

The results from 50 children aged three years and less showed some deviations from literature values derived using a full biexponential fit, with these differences reflecting the approximations inherent in this approach. The values obtained with this technique appear to be reproducible but the resulting "institutional values" are comparable to those from other centers only if identical measurement criteria are used.

CONCLUSION

A significant decline in both components of the ADC during the first few months of life was observed; in addition, the attenuated slow ADC values seen in adult white matter were only present at birth in early myelinating regions. The subsequent development of the slow ADC in white matter suggests that it is associated with myelination or processes associated with axonal development.

Central nervous system relapse following bone marrow transplantation in stage IV neuroblastoma

Neuroblastoma is the most common extracranial solid tumor in pediatrics. The disease-free survival rate for patients with stage IV neuroblastoma has improved over the past 10 years secondary to more aggressive induction chemotherapy regimens combined with autologous bone marrow transplantation. The usual sites of recurrence include the site of primary tumor, residual gross disease, bone, and bone narrow. The central nervous system, a rare site of relapse, is being involved with increasing frequency. The authors report two cases of patients with treated stage IV neuroblastoma who had relapses isolated to the CNS.

Central nervous system relapse of treated stage IV neuroblastoma

Neuroblastoma is the most common extracranial solid tumor in pediatrics. The long-term survival of patients with advanced-stage neuroblastoma has remarkably improved secondary to aggressive treatment protocols including autologous bone marrow transplant (BMT). As a result, a different natural history of this disease is being reported with unusual, late manifestations. The central nervous system (CNS), once a rare site of disease, is being involved with increasing frequency. Appropriate neuroimaging in these patients is important. Two cases of patients with treated stage IV neuroblastoma who developed isolated CNS metastases are presented. The proposed pathogenesis and neuroradiologic manifestations of this complication are reviewed.

Strokes, cutis marmorata telangiectatica congenita, and factor V Leiden

Cutis marmorata telangiectatica congenita is an uncommon, congenital cutaneous condition typified by persistent cutis marmorata and other associated abnormalities. Progressive neurologic complications are generally not a feature of the disorder. A case is reported of cutis marmorata telangiectatica congenita associated with diffuse cerebrovascular infarcts at 7 months of age. Moyamoya-like vascular abnormalities were demonstrated in addition to the factor V Leiden mutation, a congenital hypercoagulable disorder. This novel case illustrates the importance of evaluating children with strokes for congenital thrombophilic disorders.

Branchio-oto-renal dysplasia associated with tetralogy of Fallot

Branchio-oto-renal dysplasia in its full expression consists of external ear malformations, cervical fistulas or cysts, preauricular pits, hearing loss of conductive sensorineural or mixed type, and renal anomalies. The syndrome is inherited in an autosomal dominant mode. We present a sporadic case of BOR dysplasia associated with tetralogy of Fallot in a 30-month-old girl. The clinical aspects of the disease are discussed briefly.