Head Computed Tomography Scan Research Articles

Estimation of Organ Doses in Pediatric Patients for Different Imaging Protocols and Examinations

In this study, the Volume Computed Tomography Dose Index (CTDIvol) Dose Length Product (DLP), effective patient doses (ED), and organ doses were calculated for pediatric patients aged 0, 1, 5, and 10 years undergoing computed tomography (CT) examinations using the VirtualDose program, a software designed for reporting such doses. The study utilized a Toshiba Aquilion 16 CT scanner. Head, chest, and pelvis CT scans were simulated with commonly used kVp, mAs, and pitch values. The results indicated a significant difference in organ doses between standard and low-dose protocols. When kVp and mAs values were increased, ED and organ doses increased by an average of 2.5 times. Conversely, when kVp and mAs values were held constant and pitch value was increased, ED and organ doses decreased by an average of 2 times. Physicians requesting pediatric CT scans should continuously evaluate the requested examinations based on their benefits and risks. To reduce organ doses, scanning protocols should be reviewed, and low-dose protocols should be preferred. Additionally, newer generation devices that provide lower dose scanning should be utilized.

Racial difference in receiving computed tomography for head injury patients in emergency departments

Study objectivePrior studies have suggested potential racial differences in receiving imaging tests in emergency departments (EDs), but the results remain inconclusive. In addition, most prior studies may only have limited racial groups for minority patients. This study aimed to investigate racial differences in head computed tomography (CT) administration rates in EDs among patients with head injuries. MethodsPatients with head injuries who visited EDs were examined. The primary outcome was patients receiving head CT during ED visits, and the primary exposure was patient race/ethnicity, including Asian, Hispanic, Non-Hispanic Black (Black), and Non-Hispanic White (White). Multivariable logistic regression analyses were performed using the National Hospital Ambulatory Medical Care Survey database, adjusting for patients and hospital characteristics. ResultsAmong 6130 patients, 51.9% received a head CT scan. Asian head injury patients were more likely to receive head CT than White patients (59.1% versus 54.0%, difference 5.1%, p < 0.001). This difference persisted in adjusted results (odds ratio, 1.52; 95% CI, 1.06–2.16, p = 0.022). In contrast, Black and Hispanic patients have no significant difference in receiving head CT than White patients after the adjustment. ConclusionsAsian head injury patients were more likely to receive head CT than White patients. This difference may be attributed to the limited English proficiency among Asian individuals and the fact that there is a wide variety of different languages spoken by Asian patients. Future studies should examine rates of receiving other diagnostic imaging modalities among different racial groups and possible interventions to address this difference.

Delayed spinal arachnoiditis with syringomyelia following aneurysmal subarachnoid haemorrhage: a case report with patient experience

Background and importanceSyringomyelia, or the formation of fluid-filled cysts within the spinal cord, associated with delayed spinal arachnoiditis is an uncommon complication of aneurysmal subarachnoid haemorrhage. To date, about 18 cases have been reported in medical literature, with just two reported in patients under the age of 35 years.Clinical presentationA 27-year-old female patient complained of sudden, severe headaches in the occipital region, nuchal rigidity, and drowsiness when she presented at our institution. A head computed tomography scan revealed intraventricular bleeding in the lateral and fourth ventricles with more extensive haemorrhaging in the frontal horns. A left posterior inferior cerebellar artery (PICA) aneurysm was confirmed via digital subtraction angiogram, and endovascular embolization was done. Two years later, the patient reported intense pain in the lower back along with symptoms suggestive of spinal cord compression. Spinal magnetic resonance imaging (MRI) showed spinal adhesions from C1 to L4, syringomyelia with some vasogenic oedema extending from T3 to T9 level, and a cyst in the lumbar region. Consequently, a right hemilaminectomy was performed along with microsurgical release of arachnoid adhesions and placement of a subdural drain. Radiological and symptomatic improvements were observed. Since then, the patient’s clinical condition has remained stable during the past three years of follow-up visits.ConclusionsLiterature on optimal treatment modalities and patient prognosis is scarce and debated. The time for symptom improvement depends on the level and extent of spinal cord involvement. Rehabilitation may be required for most patients, as complete symptomatic recovery may not be attainable.

Low Incidence of Delayed Intracranial Hemorrhage in Geriatric Emergency Department Patients on Preinjury Anticoagulation Presenting with Blunt Head Trauma

BackgroundDelayed intracranial hemorrhage (ICH) after head injury in older patients taking anticoagulants has been reported to be as high as 7.2%. Other studies suggest much lower rates. Its incidence and clinical management are controversial, with some recommending observation and repeat head imaging at 24 h. ObjectiveOur study aims to assess the incidence of delayed ICH in geriatric Emergency Department (ED) head trauma patients prescribed preinjury anticoagulants. MethodsWe performed a prospective cohort study conducted at two hospital EDs from August 2019 to July 2020. All patients aged 65 years or older with acute head injury were eligible for enrollment. We conducted telephone follow-up at 14 and 60 days, and a chart review at 90 days. The primary study outcome was incidence of delayed ICH, which was defined as an initial negative head computed tomography scan followed by subsequent ICH believed to be caused by the initial traumatic event. We compared the rates of delayed ICH between patient cohorts based on anticoagulant use. ResultsThere were 3425 patients enrolled: 2300 (67.2%) were not on an anticoagulant, 249 (7%) were on preinjury warfarin, 780 (22.7%) were on a direct-acting oral anticoagulant, and 96 (2.8%) were on enoxaparin or heparin. The median age was 82 years (interquartile range 65-107), the majority were female (55.2%), and almost all were Caucasian (84.3%). An acute ICH was identified in 229 of 3425 (6.7%, 95% confidence interval 6–8%) and delayed ICH in 13 (0.4%, 95% confidence interval 0.2–0.6%). There were no differences in rates of delayed ICH between those who had been prescribed anticoagulants vs. those who had not (p = 0.45). ConclusionsThe incidence of delayed ICH is very low in older ED head trauma patients on prescribed pre-injury anticoagulants. Our data have important clinical implications for the management of blunt head trauma among older ED patients on anticoagulants.

Functional adaptation of the infant craniofacial system to mechanical loadings arising from masticatory forces.

The morphology and biomechanics of infant crania undergo significant changes between the pre- and post-weaning phases due to increasing loading of the masticatory system. The aims of this study were to characterize the changes in muscle forces, bite forces and the pattern of mechanical strain and stress arising from the aforementioned forces across crania in the first 48 months of life using imaging and finite element methods. A total of 51 head computed tomography scans of normal individuals were collected and analysed from a larger database of 217 individuals. The estimated mean muscle forces of temporalis, masseter and medial pterygoid increase from 30.9 to 87.0 N, 25.6 to 69.6 N and 23.1 to 58.9 N, respectively (0-48 months). Maximum bite force increases from 90.5 to 184.2 N (3-48 months). There is a change in the pattern of strain and stress from the calvaria to the face during postnatal development. Overall, this study highlights the changes in the mechanics of the craniofacial system during normal development. It further raises questions as to how and what level of changes in the mechanical forces during the development can alter the morphology of the craniofacial system.

Assessment of image quality and impact of deep learning-based software in non-contrast head CT scans

In this retrospective study, we aimed to assess the objective and subjective image quality of different reconstruction techniques and a deep learning-based software on non-contrast head computed tomography (CT) images. In total, 152 adult head CT scans (77 female, 75 male; mean age 69.4 ± 18.3 years) obtained from three different CT scanners using different protocols between March and April 2021 were included. CT images were reconstructed using filtered-back projection (FBP), iterative reconstruction (IR), and post-processed using a deep learning-based algorithm (PS). Post-processing significantly reduced noise in FBP-reconstructed images (up to 15.4% reduction) depending on the protocol, leading to improvements in signal-to-noise ratio of up to 19.7%. However, when deep learning-based post-processing was applied to FBP images compared to IR alone, the differences were inconsistent and partly non-significant, which appeared to be protocol or site specific. Subjective assessments showed no significant overall improvement in image quality for all reconstructions and post-processing. Inter-rater reliability was low and preferences varied. Deep learning-based denoising software improved objective image quality compared to FBP in routine head CT. A significant difference compared to IR was observed for only one protocol. Subjective assessments did not indicate a significant clinical impact in terms of improved subjective image quality, likely due to the low noise levels in full-dose images.

Establishment of Typical Dose Reference Level (DRL) Values for Adult Patients Undergoing Computed Tomography in Three Hospitals in Brazzaville, Congo Republic

The present study aimed at to establish typical dose reference level (DRL) values for adult patients undergoing computed tomography (CT) examinations in three hospitals in Brazzaville, Congo Republic. The examinations considered were head, chest, abdomen-pelvis, chest-abdomen-pelvis and lumbar spine CT scans. For each examination, the median of the distribution for the volume CT dose index (CTDIvol) and dose-length product (DLP) were determined. The median values were considered as the typical DRL values. Hypothesis testing was also carried out to statistically compare the mean values obtained for each participating CT facility. In the case of head scan, the typical values proposed in the present study in terms of CTDIvol and DLP were 15–48% and 28–60% lower than the DRL values reported in the literature, respectively. In the case of lumbar spine, the typical value determined in this study in terms of DLP was 48–70% greater than the DRL values provided in the literature. The typical values proposed for chest, abdomen-pelvis and chest-abdomen-pelvis were within the DRL values reported in the literature. It is possible that the adoption of the typical values proposed in the present study will help in reducing the dose received by adult patients undergoing CT examination in Congo Republic.

Neuroimaging with Rotterdam Scoring System and long-term outcomes in severe traumatic brain injury patients.

The Rotterdam Scoring System (RSS) attempts to prognosticate early mortality and early functional outcome in patients with traumatic brain injury (TBI) based on non-contrast head computed tomography (CT) imaging findings. The purpose of this study was to identify the relationship between RSS scores and long-term outcomes in patients with severe TBI. Consecutively treated patients with severe TBI enrolled between 2008 and 2011, in the prospective, observational, Brain Trauma Research Center database were included. The Glasgow Outcome Scale (GOS) was used to measure long-term functional outcomes at three, six, 12, and 24 months. GOS scores were categorized into favorable (GOS = 4-5) and unfavorable (GOS = 1-3) outcomes. RSS scores were calculated at the time of image acquisition. Of the 89 patients included, 74 (83.4%) were male, 81 (91.0%) were Caucasian, and the mean age of the cohort was 41.9±18.5 years old. Patients with an RSS score of 3 and lower were more likely to have a favorable outcome with increased survival rates than patients with RSS scores greater than 3. The RSS score determined on the head CT scan acquired at admission in a cohort of patients with severe TBI correlated with long-term survival and functional outcomes up to two years following injury.

Reduced temporal muscle thickness predicts shorter survival in patients undergoing chronic subdural haematoma drainage.

Chronic subdural haematoma (CSDH) drainage is a common neurosurgical procedure. CSDHs cause excess mortality, which is exacerbated by frailty. Sarcopenia contributes to frailty - its key component, low muscle mass, can be assessed using cross-sectional imaging. We aimed to examine the prognostic role of temporal muscle thickness (TMT) measured from preoperative computed tomography head scans among patients undergoing surgical CSDH drainage. We retrospectively identified all patients who underwent CSDH drainage within 1year of February 2019. We measured their mean TMT from preoperative computed tomography scans, tested the reliability of these measurements, and evaluated their prognostic value for postoperative survival. One hundred and eighty-eight (122, 65% males) patients (median age 78years, IQR 70-85years) were included. Thirty-four (18%) patients died within 2years, and 51 (27%) died at a median follow-up of 39months (IQR 34-42months). Intra- and inter-observer reliability of TMT measurements was good-to-excellent (ICC 0.85-0.97, P<0.05). TMT decreased with age (Pearson's r=-0.38, P<0.001). Females had lower TMT than males (P<0.001). The optimal TMT cut-off values for predicting two-year survival were 4.475mm for males and 3.125mm for females. TMT below these cut-offs was associated with shorter survival in both univariate (HR 3.24, 95% CI 1.85-5.67) and multivariate (HR 1.86, 95% CI 1.02-3.36) analyses adjusted for age, ASA grade and bleed size. The effect of TMT on mortality was not mediated by age. In patients with CSDH, TMT measurements from preoperative imaging were reliable and contained prognostic information supplemental to previously known predictors of poor outcomes.

Intracranial volumetric evaluation in postnatally repaired myelomeningocele infants

IntroductionMost myelomeningocele (MMC) cases present with ventriculomegaly or hydrocephalus, yet a comprehensive volumetric assessment of MMC intracranial structures is lacking. This study aimed to provide baseline data on intracranial structural volumes immediately after birth in MMC infants who underwent repair surgeries after birth (postnatal repair).MethodsIn this retrospective single-center study, we analyzed 52 MMC infants undergoing postnatal repair, utilizing head computed tomography scans at birth for volumetric assessment. Intracranial volume (ICV), lateral ventricles volume (LVV), choroid plexus volume (CPV), and posterior cranial fossa volume (PCFV) were measured. Hydrocephalus was classified into no hydrocephalus, progressive hydrocephalus, and hydrocephalus at birth. Comparative analysis employed the Wilcoxon rank-sum test. Receiver operating characteristic (ROC) analysis discriminated cases with and without ventriculoperitoneal shunt (VPS).ResultsThe median values were 407.50 mL for ICV, 33.18 mL for LVV, 0.67 mL for CPV, and 21.35 mL for PCFV. Thirty-seven cases (71.15%) underwent VPS. ROC analysis revealed an LVV cut-off value of 6.74 mL for discriminating cases with and without VPS. Progressive hydrocephalus showed no significant difference in ICV but significantly larger LVV compared to no hydrocephalus. Hydrocephalus at birth demonstrated statistically larger ICV and LVV compared to the other two types.ConclusionBaseline volumetric data were provided, and volumetric analysis exhibited statistical differences among three hydrocephalus types. These findings enhance our understanding of intracranial volumetric changes in MMC, facilitating more objective assessments of MMC cases.

Emergency physician gender and head computed tomography orders for older adults who have fallen.

Physicians vary in their computed tomography (CT) scan usage. It remains unclear how physician gender relates to clinical practice or patient outcomes. The aim of this study was to assess the association between physician gender and decision to order head CT scans for older emergency patients who had fallen. This was a secondary analysis of a prospective observational cohort study conducted in 11 hospital emergency departments (EDs) in Canada and the United States. The primary study enrolled patients who were 65 years and older who presented to the ED after a fall. The analysis evaluated treating physician gender adjusted for multiple clinical variables. Primary analysis used a hierarchical logistic regression model to evaluate the association between treating physician gender and the patient receiving a head CT scan. Secondary analysis reported the adjusted odds ratio (OR) for diagnosing intracranial bleeding by physician gender. There were 3663 patients and 256 physicians included in the primary analysis. In the adjusted analysis, women physicians were no more likely to order a head CT than men (OR 1.26, 95% confidence interval 0.98-1.61). In the secondary analysis of 2294 patients who received a head CT, physician gender was not associated with finding a clinically important intracranial bleed. There was no significant association between physician gender and ordering head CT scans for older emergency patients who had fallen. For patients where CT scans were ordered, there was no significant relationship between physician gender and the diagnosis of clinically important intracranial bleeding.

A simultaneous case miliary tuberculosis presenting with tuberculous meningitis: a case report

Background: Miliary tuberculosis in children could occur 20-40% simultaneously with tuberculous meningitis (TBM). Dissemination of the tuberculous bacilli from the lungs to the meninges leads to the formation of small tuberculomas, leading to TBM. Despite the availability of effective therapy, diagnosis is usually late, and mortality remains high. Case Presentation: A 15-year-old boy came to our emergency ward with the chief complaint of loss of consciousness two days before admission. The patient had a fever in the past month. Fever occurred in several episodes along with cough. The patient had a headache five days before admission. Projectile vomiting was denied. The patient had lost about five kilograms in the last month. Vital signs are stable and within normal limits. Physical examination showed lethargy, neck stiffness, and an enlarged lymph node on the neck. Neurologic examination was normal. Chest X-ray showed miliary opacities scattered over both lung fields. Cerebrospinal fluid (CSF) examination showed clear with low glucose and high cell count suggested to TBM. No bacteria were found in the CSF culture sample. A contrast head computed tomography (CT) scan revealed a leptomeningeal contrast enhancement. Active communicating hydrocephalus was also seen on a head CT scan. Eventually, Mycobacterium was detected in the gastric fluid. The patient was diagnosed with tuberculous meningitis. This patient was treated in an intensive phase of anti-tuberculous therapy and continued with an advanced phase. Conclusion: We reported cases of miliary tuberculosis simultaneously with tuberculous meningitis in a 15-year-old patient. The timely diagnosis and management will reduce morbidity and mortality.

Exposure to Ionizing Radiation from Initial Brain Computed Tomography for Injuries in the South-West Region of Cameroon

The increasing use of computed tomography (CT) in injury management is a growing concern as ionizing radiation (IR) is associated with cancer-related risks especially in young persons, who are most affected by injuries. This study aimed to assess ionizing radiation exposure from head CT in patients with injuries and to propose CT dose age-specific diagnostic reference levels (DRLs). Data was extracted from two prospectively collected CT registries over a period of 5 years at two community-based university-affiliated hospitals from 2019 to 2024. The linear relationship between CT dose (dose-length product; DLP) and age was assessed using Pearson’s correlation whilst linear regression was used to determine the strength of the relationship. The 75th percentiles and 95% confidence intervals (CIs) of the DLP were determined. Eligible initial head CT scans for patients with injuries were 1,155. There were 685 (59.31%) males (sex ratio of 1.5:1) and overall median age of 33 years (interquartile range: 21 to 46). Road traffic injuries were the source of injury in 1090 individuals (94.37%; 95% CI: 92.88 - 95.63%), followed by falls (50 cases; 4.33%; 95% CI: 3.23 - 5.67%) and assaults (10 cases; 0.87%; 95% CI: 0.42 – 1.59). The median DLP was 1,062 mGy.cm (range: 264 to 1,954 mGy.cm). There was a positive linear relationship between the DLP and the age of the patients (Pearson’s rho = 0.38, p&lt;0.001). DRLs were comparable to international values. Measures to curb the rising incidence of injuries and the continuous implementation of CT optimization techniques will reduce IR exposure.

Initial experience with astate-of-the-art mobile head CT scanner for use in neurointensive care units.

Mobile head computed tomography (CT) scanners can reduce transport-related complications in neurointensive care unit (NICU) patients and decrease the burden on NICU staff; however, the initial investment cost and reduced image quality of early mobile scanners have prevented their widespread clinical use. Here, we report our initial experience with anovel 32-row mobile CT scanner for use in NICUs. Over a2-year period, 107 patients received amobile head CT scan. The technical characteristics of the scanner and the organizational procedures are described in detail. Patient characteristics were retrospectively collected and image quality was subjectively evaluated on aLikert scale ranging from 0 to 5 and compared with astationary CT scanner. Mobile head CT was used for follow-up of intracranial hemorrhage in 51%, routine postoperative imaging in 28%, evaluation of neurological deterioration in 14%, bedside monitoring after external ventricular drain placement in 4%, and follow-up of ischemic stroke in 3% of cases. Diagnostic imaging quality was achieved in all cases, eliminating the need for stationary CT scanning. The overall image quality of mobile CT (median 4points) was inferior to that of conventional stationary CT (median 5points, p < 0.01), but was rated with 4 or 5points in the majority of cases. State-of-the-art mobile CT was found to be easy to use and maneuver and has the potential to expedite the diagnosis of NICU patients and reduce staff workload. Image quality was adequate for common NICU issues.

Isolated Traumatic Subarachnoid Hemorrhage on Head Computed Tomography Scan May Not Be Isolated: A Transforming Research and Clinical Knowledge in Traumatic Brain Injury Study (TRACK-TBI) Study.

Isolated traumatic subarachnoid hemorrhage (tSAH) after traumatic brain injury (TBI) on head computed tomography (CT) scan is often regarded as a "mild" injury, with reduced need for additional workup. However, tSAH is also a predictor of incomplete recovery and unfavorable outcome. This study aimed to evaluate the characteristics of CT-occult intracranial injuries on brain magnetic resonance imaging (MRI) scan in TBI patients with emergency department (ED) arrival Glasgow Coma Scale (GCS) score 13-15 and isolated tSAH on CT. The prospective, 18-center Transforming Research and Clinical Knowledge in Traumatic Brain Injury Study (TRACK-TBI; enrollment years 2014-2019) enrolled participants who presented to the ED and received a clinically-indicated head CT within 24 h of TBI. A subset of TRACK-TBI participants underwent venipuncture within 24 h for plasma glial fibrillary acidic protein (GFAP) analysis, and research MRI at 2-weeks post-injury. In the current study, TRACK-TBI participants age ≥17 years with ED arrival GCS 13-15, isolated tSAH on initial head CT, plasma GFAP level, and 2-week MRI data were analyzed. In 57 participants, median age was 46.0 years [quartile 1 to 3 (Q1-Q3): 34-57] and 52.6% were male. At ED disposition, 12.3% were discharged home, 61.4% were admitted to hospital ward, and 26.3% to intensive care unit. MRI identified CT-occult traumatic intracranial lesions in 45.6% (26 of 57 participants; one additional lesion type: 31.6%; 2 additional lesion types: 14.0%); of these 26 participants with CT-occult intracranial lesions, 65.4% had axonal injury, 42.3% had subdural hematoma, and 23.1% had intracerebral contusion. GFAP levels were higher in participants with CT-occult MRI lesions compared with without (median: 630.6 pg/mL, Q1-Q3: [172.4-941.2] vs. 226.4 [105.8-436.1], p = 0.049), and were associated with axonal injury (no: median 226.7 pg/mL [109.6-435.1], yes: 828.6 pg/mL [204.0-1194.3], p = 0.009). Our results indicate that isolated tSAH on head CT is often not the sole intracranial traumatic injury in GCS 13-15 TBI. Forty-six percent of patients in our cohort (26 of 57 participants) had additional CT-occult traumatic lesions on MRI. Plasma GFAP may be an important biomarker for the identification of additional CT-occult injuries, including axonal injury. These findings should be interpreted cautiously given our small sample size and await validation from larger studies.

Estimate and compensate head motion in non-contrast head CT scans using partial angle reconstruction and deep learning.

Patient head motion is a common source of image artifacts in computed tomography (CT) of the head, leading to degraded image quality and potentially incorrect diagnoses. The partial angle reconstruction (PAR) means dividing the CT projection into several consecutive angular segments and reconstructing each segment individually. Although motion estimation and compensation using PAR has been developed and investigated in cardiac CT scans, its potential for reducing motion artifacts in head CT scans remains unexplored. To develop a deep learning (DL) model capable of directly estimating head motion from PAR images of head CT scans and to integrate the estimated motion into an iterative reconstruction process to compensate for the motion. Head motion is considered as a rigid transformation described by six time-variant variables, including the three variables for translation and three variables for rotation. Each motion variable is modeled using a B-spline defined by five control points (CP) along time. We split the full projections from 360° into 25 consecutive PARs and subsequently input them into a convolutional neural network (CNN) that outputs the estimated CPs for each motion variable. The estimated CPs are used to calculate the object motion in each projection, which are incorporated into the forward and backprojection of an iterative reconstruction algorithm to reconstruct the motion-compensated image. The performance of our DL model is evaluated through both simulation and phantom studies. The DL model achieved high accuracy in estimating head motion, as demonstrated in both the simulation study (mean absolute error (MAE) ranging from 0.28 to 0.45mm or degree across different motion variables) and the phantom study (MAE ranging from 0.40 to 0.48mm or degree). The resulting motion-corrected image, , exhibited a significant reduction in motion artifacts when compared to the traditional filtered back-projection reconstructions, which is evidenced both in the simulation study (image MAE drops from 178 33HU to 37 9HU, structural similarity index (SSIM) increases from 0.60 0.06 to 0.98 0.01) and the phantom study (image MAE drops from 117 17HU to 42 19HU, SSIM increases from 0.83 0.04 to 0.98 0.02). We demonstrate that using PAR and our proposed deep learning model enables accurate estimation of patient head motion and effectively reduces motion artifacts in the resulting head CT images.

Long-term sequelae of normocephalic pansynostosis: a rare but insidious entity.

Patients with normocephalic pansynostosis, who have a grossly normal head shape, are often overlooked early in life and present late with elevated intracranial pressure (ICP) requiring timely cranial vault expansion. This study evaluates the long-term clinical outcomes of patients with normocephalic pansynostosis. We retrospectively reviewed patients with a clinical and radiographic diagnosis of primary pansynostosis who underwent vault reconstruction between 2000 and 2023. Clinical and treatment course after craniofacial interventions was followed in patients with normocephaly to assess outcomes. Thirty-five patients with primary pansynostosis were identified, of which eight (23.5%) had normocephaly and underwent initial vault expansion at a mean age of 5.0 ± 2.4years. All eight patients (50.0% male) presented with symptoms of elevated ICP including headaches (50.0%), nausea and vomiting (50.0%), and developmental delay (62.5%) and/or signs of elevated ICP including papilledema (75.0%) and radiologic thumbprinting on head computed tomography scan (87.5%). Three of the four normocephalic patients who had over 7 years of postoperative follow-up developed subjective headaches, vision changes, or learning and behavioral issues in the long-term despite successful vault reconstruction. Our longitudinal experience with this rare but insidious entity demonstrates the importance of timely intervention and frequent postoperative monitoring, which are critical to limiting long-term neurological sequelae. Multidisciplinary care by craniofacial surgery, neurosurgery, ophthalmology, and neuropsychology with follow-up into adolescence are recommended to assess for possible recurrence of elevated ICP secondary to cranio-cerebral disproportion.

248 Isolated Traumatic Subarachnoid Hemorrhage on Head Computed Tomography Scan May Not Be Isolated

INTRODUCTION: Isolated traumatic subarachnoid hemorrhage (tSAH) after traumatic brain injury (TBI) on head computed tomography (CT) is often regarded as a “mild” injury, with reduced need for additional workup. However, tSAH is also a predictor of unfavorable outcomes. Magnetic resonance imaging (MRI) and blood-based biomarkers may improve the diagnosis of concurrent intracranial injury. METHODS: The prospective, 18-center Transforming Research and Clinical Knowledge in Traumatic Brain Injury study enrolled patients presenting to ED within 24 hours (h) of TBI who received a clinically-indicated head CT. A subset underwent venipuncture within 24h for plasma glial fibrillary acidic protein (GFAP) analysis, and 2-week research MRI. Participants aged = 17-years with GCS 13-15, isolated tSAH on initial CT, GFAP, and MRI data were analyzed. RESULTS: In 57 patients, median age was 46.0-years [quartile 1 to 3 (Q1-Q3): 34-57] and 53% were male. At ED disposition, 12.3% were discharged home, 61.4% admitted to hospital ward, and 26.3% to intensive care.MRI identified additional traumatic intracranial lesions in 45.6% of patients (1 type: 31.6%; 2 types: 14.0%); of these, 65.4% had axonal injury, 42.3% subdural hematoma, and 23.1% contusion. GFAP levels were higher in patients with additional MRI lesions (median: 630.6-pg/ml, Q1-Q3: [172.4-941.2] vs. 226.4 [105.8-436.1], p = 0.049), and correlated with axonal injury severity (none: median 226.7 [109.6-435.1], traumatic axonal injury: 716.3 [304.0-892.3], diffuse axonal injury: 873.2 [407.2-1321.4], p = 0.034). CONCLUSIONS: Isolated tSAH on head CT is insufficient to rule out additional traumatic injuries in GCS 13-15 TBI. Forty-six percent of patients had additional traumatic lesions on MRI. Plasma GFAP may be an important biomarker for the identification of additional injuries, including axonal injury. Patients with isolated tSAH on CT may require close clinical surveillance and follow-up.

RADIOLOGICAL FEATURES OF THE LOCATION OF CYSTIC FORMATIONS IN THE MAXILLARY SINUS AND THEIR RELATIONSHIP WITH ALVEOLAR BONE PATHOLOGY OF THE UPPER JAW

The aim of the study. To study the features of the location of cystic formations in the maxillary sinus based on CT scans and to determine their relationship with the pathology of the upper jaw teeth.&#x0D; Materials and methods. The study involved the analysis of 552 head computed tomography scans of patients referred for examination by an otolaryngologist or dentist. The total number of individuals examined was 552, comprising 44.7% females and 55.3% males, aged 18-74 years. The investigation was conducted using the NewTom GO device with a measurement range of 155-172 mGy/cm±10%, with an error of ±4.24%. Statistical processing of data was carried out using the STATISTICA v.12.6 software.&#x0D; Results. Out of 552 computed tomography images analyzed, 92 images of individual maxillary sinuses (MS) of 79 patients with single cysts were selected. They were divided into two groups. Group 1 involved patients with cysts on the lower wall of MS (n=76). Group 2 included patients with cysts on other walls (n=16). The assessment of the ratio of 4, 5, 6, 7 tooth roots of the upper jaw to the lower wall of the upper jaw showed that the protrusion frequency in Group 1 was significantly higher (42.1%) compared to Group 2 (18.7%). Meanwhile, the average thickness of the bone over these teeth in Group 2 was significantly greater (3.4 ± 1.09 mm) than in Group 1 (1.9 ± 0.92 mm) (p=0.0003). In both patient groups, the greatest thickness was observed over tooth 4, and the smallest over tooth 7. Additionally, in 33.7% of cases, the cyst was associated with involvement of deep structures of the projecting teeth and the spread of inflammation to the lower wall of MS.&#x0D; Conclusions. Among patients referred by an otolaryngologist or dentist for CT examination to radiologically verify pathological processes in the nasal cavity, paranasal sinuses, and the upper jaw teeth, MS cysts were detected in 19.6% of cases, with 83% of them being localized in its lower parts. In patients with cysts located in the lower parts of MS, the roots protruding into the sinus cavity and a thinner layer of bone over them are more frequently observed compared to those where cysts are located in other areas of MS. In patients with cystic formations in the alveolar recess of MS, radiological signs of pathology of the upper jaw teeth are detected in 34% of cases.

Ocular biometry in rabbits using computed tomography.

To describe a repeatable method of measuring ocular structures and to establish ocular biometry reference ranges in adult domestic rabbits (Oryctolagus cuniculus) without medical history or imaging findings consistent with ophthalmic disease using a 64-slice multidetector computed tomography scanner. In this retrospective and observational anatomic study, 100 eyes from 50 rabbits without medical history or imaging findings consistent with ophthalmic disease who received a head computed tomography scan were selected for measurement of globe length, width, and height using 3D multiplanar reconstruction. Lens width and length, the anteroposterior length of the anterior and vitreous chambers, and attenuation of the lens and vitreous chamber were collected. These parameters were compared against age, sex, weight, body condition, and ear conformation. A reference guide was established, with globe width being the largest dimension (18.03 ± 0.81 mm), followed by height (17.18 ± 0.69 mm) and then length (16.64 ± 0.66 mm). Increased weight was associated with an increase in globe height (p = 2.43 × 10-5 ), length (p = 1.63 × 10-4 ), and width (p = 7.0 × 10-3 ). Increased age was associated with increased lens attenuation (p = 1.28 × 10-7 ) and increased transverse lens width (p = 1.64 × 10-3 ). Inter- and intra-observer agreement was excellent. CT is a reliable modality for measurement of ocular biometry dimensions in rabbits. These reference values can be applied to aid in identifying diseases that affect the dimensions of the ocular structures in rabbits over 18 months of age.