Imaging of pediatric hematopoietic stem cell transplant recipients: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper.

Imaging in hematopoietic stem cell transplantation patients is not targeted at evaluating the transplant per se. Rather, imaging is largely confined to evaluating peri-procedural and post-procedural complications. Alternatively, imaging may be performed to establish a baseline study for comparison should the patient develop certain post-procedural complications. This article looks to describe the various imaging modalities available with recommendations for which imaging study should be performed in specific complications. We also provide select imaging protocols for different indications and modalities for the purpose of establishing a set minimal standard for imaging in these complex patients.

Imaging of pediatric thyroid tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper.

Pediatric thyroid cancer is rare in children; however, incidence is increasing. Papillary thyroid cancer and follicular thyroid cancer are the most common subtypes, comprising about 90% and 10% of cases, respectively. This paper provides consensus imaging recommendations for evaluation of pediatric patients with thyroid cancer at diagnosis and during follow-up.

Benign longitudinal T2-hyperintense signal in the lateral cord in infancy: a cross-sectional study of spinal cord white matter maturation on magnetic resonance imaging.

BACKGROUND: Longitudinal T2-hyperintense signal is commonly seen in the spinal cord of infants and likely reflects normal unmyelinated white matter tracts, but it can be mistaken for pathology. Autopsy studies have described incomplete myelination of spinal cord in early childhood; however, the maturation timeline of the spinal cord has not been described on imaging. OBJECTIVE: The purpose of this study was to retrospectively evaluate the maturation timeline of the spinal cord on MRI to provide a baseline for image interpretation. MATERIALS AND METHODS: We retrospectively reviewed axial T2-W images of the spinal cord acquired on 1.5-tesla (T) and 3.0-T MRI in children ages 0-2 years for presence of longitudinal T2-hyperintense signal, and we subjectively graded this signal as 0 (absent) to 3 (pronounced). Further, we reviewed a summary of medical records for confounding pathology in the brain or spine. Cord signal was interpreted as normal in the clinical report by subspecialized pediatric neuroradiologists for all included children. RESULTS: We reviewed 437 MRI exams from 409 children and included 189 studies in the analysis. Longitudinal T2-hyperintense signal in the lateral cord was seen in 95% (19/20) of subjects <1 month of age and was not seen in subjects ages 21-24 months (0/15). Grade 3 signal was seen in 22% (11/50) of infants ages 0-2 months and was not seen infants older than 5 months. CONCLUSION: Characteristic symmetrical longitudinal T2 hyperintensity in the lateral spinal cord is common in infants and should not be mistaken for pathology, and it was not seen in children older than 21 months.

Dual-Energy CT Angiography for Detection of Pulmonary Emboli: Incremental Benefit of Iodine Maps.

Purpose To determine if there is added benefit of using iodine maps from dual-energy (DE) CT in addition to conventional CT angiography images to diagnose pulmonary embolism (PE). Materials and Methods In this retrospective analysis, 1144 consecutive dual-energy CT angiography examinations performed from January through September 2014 at an oncologic referral center to evaluate for PE were reviewed. The 1144 examinations included 1035 patients (mean age, 58.7 years; range, 15-99 years). First, the location, level, and type (occlusive vs nonocclusive) of PEs on conventional CT angiograms were recorded. Iodine maps were then reviewed for defects suggestive of PE. Last, CT angiograms were rereviewed to detect additional PEs suggested by the iodine map. Consensus reviews were performed for examinations with PEs. The confidence interval of percentages was calculated by using the Clopper-Pearson method. Results On 147 of 1144 (12.8%) CT angiograms, a total of 372 PEs were detected at initial review. After review of the DE CT iodine map, 27 additional PEs were found on 26 of 1144 CT angiograms (2.3%; 95% confidence interval [CI]: 1.5%, 3.3%). Of the 27 additional PEs, six (22.2%) were segmental, 21 (77.8%) were subsegmental, 24 (88.9%) were occlusive, and three (11.1%) were nonocclusive. Eleven of 1144 (1.0%; 95% CI: 0.5%, 1.7%) CT angiograms had a new diagnosis of PE after review of the DE CT iodine maps. Conclusion Dual-energy CT iodine maps show a small incremental benefit for the detection of occlusive segmental and subsegmental pulmonary emboli. © RSNA, 2018.

Diagnostic accuracy of intracellular uptake rates calculated using dynamic Gd-EOB-DTPA-enhanced MRI for hepatic fibrosis stage.

PURPOSE: To assess the diagnostic accuracy of intracellular uptake rates (Ki ), and other quantitative pharmacokinetic (PK) parameters, for hepatic fibrosis stage; to compare this accuracy with a previously published semiquantitative metric, contrast enhancement index (CEI); and to assess variability of these parameters between liver regions. MATERIALS AND METHODS: This was a case-control study design. Dynamic Gd-EOB-DTPA-enhanced 1.5T magnetic resonance imaging (MRI) was performed prospectively in 22 subjects with varying known stages of hepatic fibrosis. PK parameters and CEI were derived from the whole livers and from three fixed regions of interest (ROIs) in all subjects. Spearman rank correlation coefficients were computed to assess the relationship between fibrosis stages and each parameter. Receiver operating characteristic (ROC) curves were constructed to discriminate severe fibrosis (stages 3-4) from nonsevere fibrosis (stages 0-2). The coefficient of variation (CV) was calculated to assess variability in parameters between ROIs. RESULTS: Ki and fibrosis stage were significantly correlated (R = -0.55, 95% confidence interval [CI] [-0.79, -0.14], P = 0.01). Area under ROC curve (AUC) in distinguishing severe from nonsevere fibrosis for Ki was 0.84 (95% CI [0.65,1.00]), and for CEI was 0.64 (95% CI [0.39, 0.89]) (P = 0.0248). CV for Ki and CEI were 33.4 and 5.8, respectively. The only other parameter in the PK model having significant correlation with fibrosis stage was absolute arterial blood flow (Fa ) (R = -0.48, 95% CI [-0.75,-0.05], P = 0.03). CONCLUSION: Hepatocyte intracellular uptake rate, Ki , derived from dynamic contrast-enhanced MRI, correlates with fibrosis stage and may contribute to a noninvasive biomarker of hepatic fibrosis. LEVEL OF EVIDENCE: 2 J. Magn. Reson. Imaging 2017;45:1177-1185.

Defining Occult High-Risk Cysts of the Pineal Region: A Case Series.

BACKGROUND: Absence of hydrocephalus on neuroimaging may impart a false sense of security for patients with pineal cysts. In this case series, we characterize a subset of patients with pineal cysts having an occult presentation. Unifying features of worsening paroxysmal headaches suggesting intermittent obstructive hydrocephalus and radiographic evidence of third ventricular invagination characterize these patients as high risk. OBJECTIVE: To define features of occult, high-risk pineal cysts and outcomes of endoscopic cyst fenestration. METHODS: Charts were retrospectively reviewed for patients with pineal cysts evaluated at our institution between 2018 and 2021 who underwent endoscopic cyst fenestration. To capture cysts presenting as occult, patients were excluded if hydrocephalus was noted at presentation. Relevant clinical history, imaging, operative data, and clinical outcomes were reviewed. RESULTS: Of 50 pineal cyst patients, 4 satisfied inclusion criteria. All patients presented with worsening paroxysmal headaches. In addition, 75% (3/4) also experienced intermittent syncope. Patients exhibited no hydrocephalus (n = 3) or fluctuating ventricular size on longitudinal imaging (n = 1). In all cases, high-resolution sagittal 3-dimensional T2 magnetic resonance imaging demonstrated invagination of the cyst anteriorly into the posterior third ventricle. All patients underwent endoscopic cyst fenestration with complete symptom resolution (mean follow-up of 20.6 months; range 3.5-37.4 months). CONCLUSION: The clinical history for occult, high-risk pineal cysts is notable for worsening paroxysmal headaches and episodic alterations of consciousness suggesting intermittent obstructive hydrocephalus. Because ventricular size can appear normal on standard imaging protocols, clinical suspicion should trigger workup with high-resolution magnetic resonance imaging designed to detect these cysts. Endoscopic cyst fenestration is a safe and efficacious management strategy.

Orbital wooden foreign body manifesting as hyperdensity on computed tomography.

Detection of wooden foreign bodies within the orbit can be difficult on imaging, including computed tomography (CT). When visible, wood appears iso- or hypodense and can mimic air or fat. We report the case of a 3-year-old boy with progressive orbital cellulitis following a penetrating wood injury to the right lower lid. CT imaging revealed a linear hyperdensity contiguous with an orbital abscess. He underwent a right anterior orbitotomy with abscess drainage, during which exploration revealed a 2.3 cm retained wooden foreign body. The appearance of wood as hyperdense on imaging is unusual. In the appropriate context, high clinical suspicion for retained wood should be maintained with any irregularity on CT imaging.

Repeat magnetic resonance imaging-guided focused ultrasound thalamotomy for recurrent essential tremor: case report and review of MRI findings.

An 86-year-old right-handed man with medically refractory essential tremor was treated using left-sided MRI-guided focused ultrasound (MRgFUS) thalamotomy targeting the dentatorubrothalamic tract (DRTT) at its intersection with the ventral intermediate nucleus of the thalamus, with immediate symptomatic improvement and immediate postprocedure imaging demonstrating disruption of the DRTT. The patient experienced a partial return of symptoms 9 weeks following the procedure, and MRI demonstrated retraction of the left thalamic ablation site. The patient underwent repeat left-sided MRgFUS thalamotomy 4 months after initial treatment, resulting in reduced tremor. MR thermometry temperature measurements during the second MRgFUS procedure were unreliable with large fluctuations and false readings, likely due to susceptibility effects from the initial MRgFUS procedure. Final sonications were therefore monitored using the amount of energy delivered. The patient fared well after the second procedure and had sustained improvement in tremor control at the 12-month follow-up. This is the first report to describe the technical challenges of repeat MRgFUS with serial imaging.

Imaging of Temporal Bone Trauma: A Clinicoradiologic Perspective.

Imaging plays an important role in the evaluation of temporal bone trauma. Certain imaging findings can significantly change patient management or change surgical approach. Precise knowledge of clinical or surgical management can guide the review of imaging to detect these key findings. This article reviews the clinical and imaging findings as well as management of complications from temporal bone trauma, including hearing loss, vertigo, perilymphatic fistula, cerebrospinal fluid leak, facial nerve injury and vascular injury.

Beals syndrome with middle and inner ear dysplasia and encephalocele: A case report and review of imaging findings.

A 10-year-old male with history of Beals syndrome presented with hearing loss and was found to have middle and inner ear dysplasia and left temporal encephalocele on imaging. Beals syndrome is a rare autosomal dominant connective tissue disorder caused by a mutation in the fibrillin-2 gene. Skeletal manifestations of Beals have been reported, including anomalies of the long bones, calvarium, and spine. External ear abnormalities with "crumpled ear" deformity are seen in the majority of patients. This is the first case to report imaging findings of the middle and inner ear in a patient with Beals.

Diffusion tensor imaging and quantitative susceptibility mapping as diagnostic tools for motor neuron disorders.

PURPOSE: Diffusion tensor imaging (DTI) and quantitative susceptibility mapping (QSM) have been proposed as methods to aid in the diagnosis of amyotrophic lateral sclerosis (ALS) and primary lateral sclerosis (PLS), both diseases affecting upper motor neurons. We test the performance of DTI and QSM alone and in combination to distinguish patients with diseases affecting upper motor neurons (ALS/PLS) from patients with other motor symptom-predominant neurologic disorders. METHODS: 3.0 Tesla MRI with DTI and QSM in patients referred to a subspecialty neurology clinic for evaluation of motor symptom-predominant neurologic disorders were retrospectively reviewed. Corticospinal tract fractional anisotropy and maximum motor cortex susceptibility were measured. Subjects were categorized by diagnosis and imaging metrics were compared between groups using Student's t-tests. Receiver operating characteristic curves were generated for imaging metrics alone and in combination. RESULTS: MRI scans for 43 patients with ALS or PLS and 15 patients with motor symptom predominant, non-upper motor neuron disease (mimics) were reviewed. Fractional anisotropy was lower (0.57 vs. 0.60, p < 0.01) and maximum motor cortex magnetic susceptibility higher (64.4 vs. 52.7, p = 0.01) in patients with ALS/PLS compared to mimics. There was no significant difference in area under the curve for these metrics alone (0.73, 0.63; p > 0.05) or in combination (0.75; p > 0.05). CONCLUSION: We found significant differences in DTI and QSM metrics in patients with diseases affecting upper motor neurons (ALS/PLS) compared to mimics, but no significant difference in the performance of these metrics in diagnosing ALS/PLS compared to mimics.

Magnetic resonance-guided focused ultrasound for ablation of mesial temporal epilepsy circuits: modeling and theoretical feasibility of a novel noninvasive approach.

OBJECTIVE: The authors tested the feasibility of magnetic resonance-guided focused ultrasound (MRgFUS) ablation of mesial temporal lobe epilepsy (MTLE) seizure circuits. Up to one-third of patients with mesial temporal sclerosis (MTS) suffer from medically refractory epilepsy requiring surgery. Because current options such as open resection, laser ablation, and Gamma Knife radiosurgery pose potential risks, such as infection, hemorrhage, and ionizing radiation, and because they often produce visual or neuropsychological deficits, the authors developed a noninvasive MRgFUS ablation strategy for mesial temporal disconnection to mitigate these risks. METHODS: The authors retrospectively reviewed 3-T MRI scans obtained with diffusion tensor imaging (DTI). The study group included 10 patients with essential tremor (ET) who underwent pretreatment CT and MRI prior to MRgFUS, and 2 patients with MTS who underwent MRI. Fiber tracking of the fornix-fimbria pathway and inferior optic radiations was performed, ablation sites mimicking targets of open posterior hippocampal disconnection were modeled, and theoretical MRgFUS surgical plans were devised. Distances between the targets and optic radiations were measured, helmet angulations were prescribed, and the numbers of available MRgFUS array elements were calculated. RESULTS: Tractograms of fornix-fimbria and optic radiations were generated in all ET and MTS patients successfully. Of the 10 patients with both the CT and MRI data necessary for the analysis, 8 patients had adequate elements available to target the ablation site. A margin (mean 8.5 mm, range 6.5-9.8 mm) of separation was maintained between the target lesion and optic radiations. CONCLUSIONS: MRgFUS offers a noninvasive option for seizure tract disruption. DTI identifies fornix-fimbria and optic radiations to localize optimal ablation targets and critical surrounding structures, minimizing risk of postoperative visual field deficits. This theoretical modeling study provides the necessary groundwork for future clinical trials to apply this novel neurosurgical technique to patients with refractory MTLE and surgical contraindications, multiple prior surgeries, or other factors favoring noninvasive treatment.

Toxic encephalopathy due to paradichlorobenzene toxicity: a case report and review of imaging characteristics.

Neurotoxicity following paradichlorobenzene (PDCB) exposure is rare and can occur in patients with pica and mothball or toilet cake ingestion. We present a rare case of toxic encephalopathy due to PDCB mothball inhalation and ingestion and describe the rapidly progressive leukoencephalopathy seen on computed tomography, magnetic resonance, and magnetic resonance spectroscopy. Given the nonspecificity of clinical and imaging findings, it is important for radiologists to maintain a high index of suspicion for toxic encephalopathy.

MRI safety: a report of current practice and advancements in patient preparation and screening.

MRI offers detailed diagnostic images without ionizing radiation; however, there are considerable safety concerns associated with high electromagnetic field strength. With increasing use of high and ultra high (7T) magnetic field strength, adequate patient preparation and screening for ferrous material is increasingly important. We review current safety standards for patient screening and preparation and how they are implemented at our institution. In addition, we describe a novel supplemental screening technique wherein the lights are dimmed in response to detected ferrous metal at the threshold of Zone IV.

Patient acuity rating: quantifying clinical judgment regarding inpatient stability.

BACKGROUND: New resident work-hour restrictions are expected to result in further increases in the number of handoffs between inpatient care providers, a known risk factor for poor outcomes. Strategies for improving the accuracy and efficiency of provider sign-outs are needed. OBJECTIVE: To develop and test a judgment-based scale for conveying the risk of clinical deterioration. DESIGN: Prospective observational study. SETTING: University teaching hospital. SUBJECTS: Internal medicine clinicians and patients. MEASUREMENTS: The Patient Acuity Rating (PAR), a 7-point Likert score representing the likelihood of a patient experiencing a cardiac arrest or intensive care unit (ICU) transfer within the next 24 hours, was obtained from physicians and midlevel practitioners at the time of sign-out. Cross-covering physicians were blinded to the results, which were subsequently correlated with outcomes. RESULTS: Forty eligible clinicians consented to participate, providing 6034 individual scores on 3419 patient-days. Seventy-four patient-days resulted in cardiac arrest or ICU transfer within 24 hours. The average PAR was 3 ± 1 and yielded an area under the receiver operator characteristics curve (AUROC) of 0.82. Provider-specific AUROC values ranged from 0.69 for residents to 0.85 for attendings (P = 0.01). Interns and midlevels did not differ significantly from the other groups. A PAR of 4 or higher corresponded to a sensitivity of 82% and a specificity of 68% for predicting cardiac arrest or ICU transfer in the next 24 hours. CONCLUSIONS: Clinical judgment regarding patient stability can be reliably quantified in a simple score with the potential for efficiently conveying complex assessments of at-risk patients during handoffs between healthcare members.

Assessing the impact of immersive simulation on clinical performance during actual in-hospital cardiac arrest with CPR-sensing technology: A randomized feasibility study.

AIM: Advanced simulation tools are increasingly being incorporated into cardiopulmonary resuscitation (CPR) training. These educational methods have been shown to improve trainee performance in simulated settings, but translation into clinical practice remains unknown for many aspects of CPR quality. This study attempts to measure the impact of simulation-based training for resuscitation team leaders on some measures of CPR quality during actual in-hospital resuscitation attempts. METHODS: In this prospective, randomized interventional cluster trial, internal medicine resident physicians (post-graduate year 2) were randomized using a random number generator to participate in a 4-h, immersive simulation course in cardiopulmonary resuscitation leadership using a high-fidelity simulator with video debriefing prior to serving as resuscitation team leaders at an academic medical center. Objective metrics of actual resuscitation performance were obtained from a CPR-sensing monitor/defibrillator. RESULTS: Thirty-two residents were randomized to receive simulation training or no additional training between April and July 2007 and data were collected following 98 actual resuscitations between July 2007 and June 2008. CPR quality from resuscitations led by 14 simulation-trained and 16 control group residents was similar in terms of mean compression depth (48 vs 49 mm; p = 0.53); compression rate (107 vs 104 min⁻¹; p = 0.30); ventilation rate (12 vs 12 min⁻¹; p = 0.45) and no-flow fraction (0.08 vs 0.07; p = 0.34). CONCLUSIONS: Although we failed to detect any significant differences in objective measures of CPR quality, we have demonstrated that CPR-sensing technology has the potential for use in assessing the impact of a simulation curriculum on some aspects of actual resuscitation performance. A larger study, performed in a setting with lower baseline performance, would be required to assess the specific simulation curriculum.

Capnography and chest-wall impedance algorithms for ventilation detection during cardiopulmonary resuscitation.

OBJECTIVE: Hyperventilation is both common and detrimental during cardiopulmonary resuscitation (CPR). Chest-wall impedance algorithms have been developed to detect ventilations during CPR. However, impedance signals are challenged by noise artifact from multiple sources, including chest compressions. Capnography has been proposed as an alternate method to measure ventilations. We sought to assess and compare the adequacy of these two approaches. METHODS: Continuous chest-wall impedance and capnography were recorded during consecutive in-hospital cardiac arrests. Algorithms utilizing each of these data sources were compared to a manually determined "gold standard" reference ventilation rate. In addition, a combination algorithm, which utilized the highest of the impedance or capnography values in any given minute, was similarly evaluated. RESULTS: Data were collected from 37 cardiac arrests, yielding 438min of data with continuous chest compressions and concurrent recording of impedance and capnography. The manually calculated mean ventilation rate was 13.3+/-4.3/min. In comparison, the defibrillator's impedance-based algorithm yielded an average rate of 11.3+/-4.4/min (p=0.0001) while the capnography rate was 11.7+/-3.7/min (p=0.0009). There was no significant difference in sensitivity and positive predictive value between the two methods. The combination algorithm rate was 12.4+/-3.5/min (p=0.02), which yielded the highest fraction of minutes with respiratory rates within 2/min of the reference. The impedance signal was uninterpretable 19.5% of the time, compared with 9.7% for capnography. However, the signals were only simultaneously non-interpretable 0.8% of the time. CONCLUSIONS: Both the impedance and capnography-based algorithms underestimated the ventilation rate. Reliable ventilation rate determination may require a novel combination of multiple algorithms during resuscitation.

Rescuer fatigue during actual in-hospital cardiopulmonary resuscitation with audiovisual feedback: a prospective multicenter study.

BACKGROUND: Rescuer fatigue during cardiopulmonary resuscitation (CPR) is a likely contributor to variable CPR quality during clinical resuscitation efforts, yet investigations into fatigue and CPR quality degradation have only been performed in simulated environments, with widely conflicting results. OBJECTIVE: We sought to characterize CPR quality decay during actual in-hospital cardiac arrest, with regard to both chest compression (CC) rate and depth during the delivery of CCs by individual rescuers over time. METHODS: Using CPR recording technology to objectively quantify CCs and provide audiovisual feedback, we prospectively collected CPR performance data from arrest events in two hospitals. We identified continuous CPR "blocks" from individual rescuers, assessing CC rate and depth over time. RESULTS: 135 blocks of continuous CPR were identified from 42 cardiac arrests at the two institutions. Median duration of continuous CPR blocks was 112s (IQR 101-122). CC rate did not change significantly over single rescuer performance, with an initial mean rate of 105+/-11/min, and a mean rate after 3 min of 106+/-9/min (p=NS). However, CC depth decayed significantly between 90s and 2 min, falling from a mean of 48.3+/-9.6mm to 46.0+/-9.0mm (p=0.0006) and to 43.7+/-7.4mm by 3 min (p=0.002). CONCLUSIONS: During actual in-hospital CPR with audiovisual feedback, CC depth decay became evident after 90s of CPR, but CC rate did not change. These data provide clinical evidence for rescuer fatigue during actual resuscitations and support current guideline recommendations to rotate rescuers during CC delivery.