Comparison of Image Quality and Radiation Dose in Pediatric Temporal Bone CT using Photon Counting Detectors CT and Energy Integrating Detectors CT.

BACKGROUND AND PURPOSE: To compare the image quality and radiation dose of temporal bone CT scans in pediatric patients acquired with photon counting detectors (PCD) CT and energy integrating detectors (EID) CT. MATERIALS AND METHODS: The retrospective study included a total of 110 pediatric temporal bone CT scans (PCD-CT, n=52; EIDCT, n=58). Two independent readers evaluated the spatial resolution of 4 anatomical structures (tympanic membrane, incudostapedial joint, stapedial crura, and cochlear modiolus) and overall image quality using a 4-point scale. Inter-reader agreement was assessed. Dose length product (DLP) for each CT was compared, and subgroup analyses were performed based on age (under 3 years, 3-5 years, 6-11 years, and 12 years and above). RESULTS: PCD-CT demonstrated statistically significantly higher scores than EID-CT for all items (tympanic membrane, 2.9 vs. 2.4; incudostapedial joint, 3.6 vs. 2.6, stapedial crura, 3.2 vs. 2.4; cochlear modiolus, 3.4 vs. 2.8; overall image quality, 3.6 vs. 2.8; p<0.05). Inter-reader agreement ranged from good to excellent (ICCs, 0.6-0.81). PCD-CT exhibited a 43% dose reduction compared to EID-CT, with a particularly substantial reduction of over 70% in the subgroups of children under 6 years. CONCLUSIONS: PCD temporal bone CT achieves significantly superior imaging quality at a lower radiation dose compared to EID-CT. ABBREVIATIONS: PCD-CT = photon counting detectors CT; EID-CT = energy integrating detectors CT; DLP = dose length product; AEC = automatic exposure control; ICC = interclass correlation coefficient.

Routine Echocardiography is not Required in Neonates with Arterial Ischemic Stroke.

OBJECTIVE: Current guidelines suggest routine echocardiography (ECHO) in the acute phase to exclude a cardiac source for neonatal arterial ischemic stroke (NAIS). However, the commonly assumed embolic origin from a cardiac source for NAIS is challenged and the need for ECHO in NAIS remains questionable, especially during the era of standard fetal anomaly scanning. Our hypothesis is that any complex cardiac defects potentially causing NAIS would likely be detected during routine prenatal scans, thus possibly making routine postnatal ECHO redundant. This study aimed to determine the prevalence of significant cardiac risk factors and evaluate the necessity of routine postnatal ECHO in NAIS during the routine use of prenatal fetal sonography. STUDY DESIGN: Retrospective review of 54 infants diagnosed with NAIS via brain magnetic resonance imaging who underwent an ECHO evaluation during the acute period to exclude potential cardiac origins for NAIS. RESULTS: Postnatal ECHO revealed no intracardiac thrombus or vegetation, and only identified structural heart anomalies in three (5%) infants. Interestingly, these three cases had already been diagnosed with syndromic conditions or chromosomal malformations prenatally. In the remaining infants, postnatal ECHO was either normal or showed minor abnormalities unlikely to have contributed to the stroke. The detection rates of complex cardiac anomalies from prenatal scans and postnatal ECHO were statistically similar (p = 0.617). CONCLUSION: The probability of ECHO to exclude cardiac sources for NAIS is so low that in the era of standard fetal anomaly scanning, routine postnatal ECHO may not be necessary for all NAIS infants, except when chromosomal malformations are detected. KEY POINTS: · Guidelines recommend an acute phase ECHO to identify a cardiac source of NAIS.. · ECHO not effective at excluding NAIS's cardiac origin for infants with normal fetal scans.. · Routine postnatal ECHO is unnecessary in NAIS infants, except with genetic abnormalities..

Central Nervous System Systemic Lupus Erythematosus: Pathophysiologic, Clinical, and Imaging Features.

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterized by multiple immunologic abnormalities and has the potential to involve the central nervous system (CNS). The prevalence of SLE seems to be growing, possibly because of earlier diagnosis and improved survival; however, the associated mortality is still high. The mortality is associated with disease-related risk factors such as lupus disease activity, young age, and organ damage or with antiphospholipid syndrome (APS). Neuropsychiatric SLE (NPSLE), which is caused by SLE-related CNS involvement, comprises a broad range of neurologic and psychiatric manifestations with varying severity, which can make this disease indistinguishable from other conditions that are unrelated to SLE. No unifying pathophysiology has been found in the etiology of NPSLE, suggesting that this condition has multiple contributors such as various immune effectors and the brain-intrinsic neuroimmune interfaces that are breached by the immune effectors. The postulated neuroimmune interfaces include the blood-brain barrier, blood-cerebrospinal fluid barrier, meningeal barrier, and glymphatic system. On the basis of the immunologic, pathologic, and imaging features of NPSLE, the underlying pathophysiology can be classified as vasculitis and vasculopathy, APS, demyelinating syndrome, or autoimmune antibody-mediated encephalitis. Each pathophysiology has different imaging characteristics, although the imaging and pathophysiologic features may overlap. Moreover, there are complications due to the immunocompromised status caused by SLE per se or by SLE treatment. Radiologists and clinicians should become familiar with the underlying mechanisms, radiologic findings, and complications of NPSLE, as this information may aid in the diagnosis and treatment of NPSLE. Online supplemental material is available for this article. ©RSNA, 2022.

Automated Segmentation and Severity Analysis of Subdural Hematoma for Patients with Traumatic Brain Injuries.

Detection and severity assessment of subdural hematoma is a major step in the evaluation of traumatic brain injuries. This is a retrospective study of 110 computed tomography (CT) scans from patients admitted to the Michigan Medicine Neurological Intensive Care Unit or Emergency Department. A machine learning pipeline was developed to segment and assess the severity of subdural hematoma. First, the probability of each point belonging to the hematoma region was determined using a combination of hand-crafted and deep features. This probability provided the initial state of the segmentation. Next, a 3D post-processing model was applied to evolve the initial state and delineate the hematoma. The recall, precision, and Dice similarity coefficient of the proposed segmentation method were 78.61%, 76.12%, and 75.35%, respectively, for the entire population. The Dice similarity coefficient was 79.97% for clinically significant hematomas, which compared favorably to an inter-rater Dice similarity coefficient. In volume-based severity analysis, the proposed model yielded an F1, recall, and specificity of 98.22%, 98.81%, and 92.31%, respectively, in detecting moderate and severe subdural hematomas based on hematoma volume. These results show that the combination of classical image processing and deep learning can outperform deep learning only methods to achieve greater average performance and robustness. Such a system can aid critical care physicians in reducing time to intervention and thereby improve long-term patient outcomes.

Three-Dimensional CT Morphometric Image Analysis of the Clivus and Sphenoid Sinus in Chiari Malformation Type I.

This study evaluated three-dimensional (3D) volumetric image reconstructions to identify morphological differences of the clivus and sphenoid sinus on computed tomography (CT) scans of Chiari malformation type I (CMI) and control subjects. Axial CT images of adult females for 30 CMI subjects and 30 age and body mass index (BMI) matched controls were used for this retrospective study. 3D volumetric reconstructions were created from the bone windows of axial data following image registration for position and orientation correction of the head. The volume, surface area, linear dimensions and spatial position in the x, y, and z-axes were computed separately for the clivus and the sphenoid sinus for each subject. Eleven parameters were found to be significantly different between CMI subjects compared to controls. Most notably, clivus volume was reduced by 31% on average in CMI subjects. In contrast, we found that the sphenoid sinus volume was 38% greater on average in CMI subjects. Moreover, clivus length, height, width, and thickness were 3.7, 2.8, 3.0 and 9.4 mm reduced, respectively, in CMI subjects. This is the first study to demonstrate cephalometric differences in the 3D morphology of the clivus and sphenoid sinus between CMI subjects and controls.

A Retrospective 2D Morphometric Analysis of Adult Female Chiari Type I Patients with Commonly Reported and Related Conditions.

Purpose: Researchers have sought to better understand Chiari type I malformation (CMI) through morphometric measurements beyond tonsillar position (TP). Soft tissue and bone structures within the brain and craniocervical junction have been shown to be different for CMI patients compared to healthy controls. Yet, several morphological characteristics have not been consistently associated with CMI. CMI is also associated with different prevalent conditions (PCs) such as syringomyelia, pseudotumor, Ehlers-Danlos syndrome (EDS), scoliosis, and craniocervical instability. The goal of this study was two-fold: (1) to identify unique morphological characteristics of PCs, and (2) to better explain inconsistent results from case-control comparisons of CMI. Methods: Image, demographic, and PC information was obtained through the Chiari1000, a self-report web-accessed database. Twenty-eight morphometric measurements (MMs) were performed on the cranial MR images of 236 pre-surgery adult female CMI participants and 140 female healthy control participants. Custom software was used to measure 28 structures within the posterior cranial fossa (PCF) compartment, craniocervical junction, oral cavity, and intracranial area on midsagittal MR images for each participant. Results: Morphometric analysis of adult females indicated a smaller McRae line length in CMI participants with syringomyelia compared to those without syringomyelia. TP was reduced in CMI participants with EDS than those without EDS. Basion to posterior axial line was significantly longer in CMI participants with scoliosis compared to those without scoliosis. No additional MMs were found to differ between CMI participants with and without a specific PC. Four morphometric differences were found to be consistently different between CMI participants and healthy controls regardless of PC: larger TP and a smaller clivus length, fastigium, and corpus callosum height in CMI participants. Conclusion: Syringomyelia, EDS, and scoliosis were the only PCs that showed significant morphometric differences between CMI participants. Additionally, four midsagittal MR-based MMs were found to be significantly different between healthy controls and CMI participants regardless of the presence of one or more PCs. This study suggests that the prevalence of comorbid conditions are not strongly related to CMI morphology, and that inconsistent findings in the radiographic literature cannot be explained by varying prevalence of comorbid conditions in CMI study samples.

Automated subdural hematoma segmentation for traumatic brain injured (TBI) patients.

Traumatic brain injury is a serious public health problem in the U.S. contributing to a large portion of permanent disability. However, its early management and treatment could limit the impact of the injury, save lives and reduce the burden of cost for patients as well as healthcare systems. Subdural hematoma is one of the most common types of TBI, which its visual detection and quantitative evaluation are time consuming and prone to error. In this study, we propose a fully auto-mated machine learning based approach for 3D segmentation of convexity subdural hematomas. Textural, statistical and geometrical features of sample points from intracranial region are extracted based on head Computed Tomography (CT) images. Then, a tree bagger classifier is implemented to classify each pixel as hematoma or no-hematoma. Our method yields sensitivity, specificity and area under the receiver operating curve (AUC) of 85:02%, 73:74% and 0:87 respectively.

Limited short-term prognostic utility of cerebral NIRS during neonatal therapeutic hypothermia.

OBJECTIVE: We evaluated the utility of amplitude-integrated EEG (aEEG) and regional oxygen saturation (rSO2) measured using near-infrared spectroscopy (NIRS) for short-term outcome prediction in neonates with hypoxic ischemic encephalopathy (HIE) treated with therapeutic hypothermia. METHODS: Neonates with HIE were monitored with dual-channel aEEG, bilateral cerebral NIRS, and systemic NIRS throughout cooling and rewarming. The short-term outcome measure was a composite of neurologic examination and brain MRI scores at 7 to 10 days. Multiple regression models were developed to assess NIRS and aEEG recorded during the 6 hours before rewarming and the 6-hour rewarming period as predictors of short-term outcome. RESULTS: Twenty-one infants, mean gestational age 38.8 ± 1.6 weeks, median 10-minute Apgar score 4 (range 0-8), and mean initial pH 6.92 ± 0.19, were enrolled. Before rewarming, the most parsimonious model included 4 parameters (adjusted R(2) = 0.59; p = 0.006): lower values of systemic rSO2 variability (p = 0.004), aEEG bandwidth variability (p = 0.019), and mean aEEG upper margin (p = 0.006), combined with higher mean aEEG bandwidth (worse discontinuity; p = 0.013), predicted worse short-term outcome. During rewarming, lower systemic rSO2 variability (p = 0.007) and depressed aEEG lower margin (p = 0.034) were associated with worse outcome (model-adjusted R(2) = 0.49; p = 0.005). Cerebral NIRS data did not contribute to either model. CONCLUSIONS: During day 3 of cooling and during rewarming, loss of physiologic variability (by systemic NIRS) and invariant, discontinuous aEEG patterns predict poor short-term outcome in neonates with HIE. These parameters, but not cerebral NIRS, may be useful to identify infants suitable for studies of adjuvant neuroprotective therapies or modification of the duration of cooling and/or rewarming.

Distribution and severity of hypoxic-ischaemic lesions on brain MRI following therapeutic cooling: selective head versus whole body cooling.

BACKGROUND: Whole body cooling (WBC) cools different parts of the brain uniformly, and selective head cooling (SHC) cools the superficial brain more than the deeper brain structures. In this study, the authors hypothesised that the hypoxic-ischaemic lesions on brain MRI following cooling would differ between modalities of cooling. AIM: To compare the frequency, distribution and severity of hypoxic-ischaemic lesions on brain MRI between SHC or WBC. METHODS: In a single centre retrospective study, 83 infants consecutively cooled using either SHC (n=34) or WBC (n=49) underwent brain MRI. MRI images were evaluated by a neuroradiologist, who was masked to clinical parameters and outcomes, using a basal ganglia/watershed (BG/W) scoring system. Higher scores (on a scale of 0 to 4) were given for more extensive injury. The score has been reported to be predictive of neuromotor and cognitive outcome at 12 months. RESULTS: The two groups were similar for severity of depression as assessed by a history of an intrapartum sentinel event, Apgar scores, initial blood pH and base deficit and early neurological examination. However, abnormal MRI was more frequent in the SHC group (SHC 25 of 34, 74% vs WBC 22 of 49, 45%; p=0.0132, OR 3.4, 95% CI 1.3 to 8.8). Infants from the SHC group also had more severe hypoxic-ischaemic lesions (median BG/W score: SHC 2 vs WBC 0, p=0.0014). CONCLUSIONS: Hypoxic-ischaemic lesions on brain MRI following therapeutic cooling were more frequent and more severe with SHC compared with WBC.

The relationship between clinically identifiable intrapartum sentinel events and short-term outcome after therapeutic hypothermia.

OBJECTIVE: To determine the impact of intrapartum sentinel events on short-term outcome post-hypothermia. STUDY DESIGN: Records of 77 infants of 36 weeks' gestation or more, who received therapeutic hypothermia, were reviewed. Some were delivered after a clinically identifiable intrapartum sentinel event (IISE). All survivors had brain magnetic resonance imaging (MRI) at 7 to 10 days of life. The primary outcome of neonatal death related to hypoxic-ischemic encephalopathy was compared in infants born with (n = 39) or without an IISE (n = 38). MRI abnormalities were also compared. Logistic regression analysis was used to determine the variables predicting the primary outcome. RESULTS: The two groups had similar Apgar scores, initial blood pHs, and early neurologic examinations. Base deficit was more severe in the IISE group. Neonatal death and hypoxic-ischemic injury was shown on brain MRI with basal nuclei, cortical, and subcortical white matter lesions extending beyond the watershed areas in infants surviving beyond the neonatal period were more common in the IISE group (P = .014; OR 11.1; 95% CI 1.3-92.6; and P = .034; OR 4.1; 95% CI 1.1-14.9, respectively). Multivariate analysis identified IISE (P = .023; OR 12.2; 95% CI 1.4-105.8) to be independently associated with neonatal death. CONCLUSIONS: IISEs are associated with neonatal death and severe injury as shown in brain MRI, even after hypothermia.

New parameter of hemoglobin status as an indicator of efficacy of preoperative angioembolization in extracranial hypervascular tumours.

BACKGROUND: Routinely, the standard for measuring the success of preoperative embolization procedure as an adjunct in the management of head and neck vascular tumours has been to evaluate the amount of blood loss, duration of surgery, and intraoperative neurovascular injuries. OBJECTIVE: We hypothesized that the rate of change in the preoperative hemoglobin status would more accurately and objectively reflect the effectiveness of the embolization technique. MATERIALS AND METHODS: Twenty-six patients with extracranial vascular tumours were divided into two groups (A and B) of 13. Group A patients had preoperative embolization and group B patients directly underwent surgery. The difference between the preoperative and postoperative hemoglobin levels and the percentage rate of change of hemoglobin status were calculated. RESULTS: The percentage rate of change of preoperative to postoperative hemoglobin is less in group A (9.43%) when compared with group B (18.27%). The ratio of preoperative to postoperative hemoglobin in the two groups is also statistically significant (1:1.9). CONCLUSIONS: The percentage rate of change of preoperative to postoperative hemoglobin and the ratio of preoperative to postoperative hemoglobin are more accurate and objective parameters for assessment of success of preoperative embolizations rather than other variables such as intraoperative blood loss or duration of surgery.