Brain CT Studies Research Articles

Arachnoid Cyst Burst in Presence of Contralateral Nomura IV Subdural Hematoma: After Effects of Traumatic Kickback and Intracranial Pressure

Intracranial arachnoid cysts are benign fluid-filled sacs located between the brain and the arachnoid membrane. Their rupture is an uncommon event, often associated with trauma or an underlying pathology. Here, we present a case of a 61-year-old woman with a ruptured arachnoid cyst coinciding with a contralateral subdural hematoma. The patient manifested a persistent headache, balance disorders and right facial paresthesia. Brain CT study showed a right temporo-polar cyst (known to the patient) and a right parietal chronic Subdural Hematoma (cSDH). Although the kickback may contribute to bursting or weakening of cyst integrity, the CT-density pattern of the cSDH, according to Nomura classification is to be considered associated with increased fibrinolysis activity and potentially with parenchyma compression. This case highlights the importance of considering arachnoid cyst rupture as a potential indirect consequence of head trauma kickback, particularly in the presence of contralateral intracranial hemorrhage.

Arachnoid Cyst Burst in Presence of Contralateral Nomura IV Subdural Hematoma: After Effects of Traumatic Kickback and Intracranial Pressure

Intracranial arachnoid cysts are benign fluid-filled sacs located between the brain and the arachnoid membrane. Their rupture is an uncommon event, often associated with trauma or an underlying pathology. Here, we present a case of a 61-year-old woman with a ruptured arachnoid cyst coinciding with a contralateral subdural hematoma. The patient manifested a persistent headache, balance disorders and right facial paresthesia. Brain CT study showed a right temporo-polar cyst (known to the patient) and a right parietal chronic Subdural Hematoma (cSDH). Although the kickback may contribute to bursting or weakening of cyst integrity, the CT-density pattern of the cSDH, according to Nomura classification is to be considered associated with increased fibrinolysis activity and potentially with parenchyma compression. This case highlights the importance of considering arachnoid cyst rupture as a potential indirect consequence of head trauma kickback, particularly in the presence of contralateral intracranial hemorrhage.

Secondary Benefits of Microsurgical Intervention on the Vertebral Artery (V1 Segment) for Refractory Vertebrobasilar Insufficiency: Alleviation of Parkinsonism-Like Symptoms

ObjectiveTo investigate the outcomes of micro-neurosurgical interventions on V1 segment of vertebral artery (VA) in patients with refractory vertebrobasilar insufficiency (VBI) due to dolicoarteriopathy and external compressions and to assess the secondary benefits of Parkinsonism-like symptoms. MethodsRetrospective analysis encompassed 101 patients treated for VA dolicoarteriopathy or compression-related refractory VBI from 2016-2023. Of these, 16 patients exhibited drug-resistant Parkinsonism-like symptoms. The diagnostic evaluation included cerebral CT/MR angiography or DSA and brain CT or MR perfusion studies, corroborated by preoperative and 6- and 12-month postoperative MDS-UPDRS Part 3 assessments. Data was analyzed through Turkey's 'E-nabız' system, employing Stata16 for statistical scrutiny. ResultsA significant reduction in MDS-UPDRS scores was observed (preoperative: 26.75 ± 10.91; 6 months: 23.09 ± 9.24; 12 months: 22.5 ± 8.73; P<0.001). Postoperative follow-up denoted that 43.7% of patients ceased medication, and 50% reduced antiparkinsonian drugs. The micro-neurosurgical approach resulted in complete remission of VBI-related symptoms in 84.6% of patients, with the rest showing partial or marked improvement. At six months post-operation, perfusion studies revealed posterior border zone or cerebellar perfusion enhancements in 81% (13 out of 16) of patients, with full symptom resolution, while the remaining 19% (3 out of 16) showed partial perfusion and clinical improvements, particularly in regions supplied by the posterior cerebellar artery (PCA) or posterior inferior cerebellar artery (PICA). The absence of operative mortality and minimal transient morbidities underscored the procedure's safety. ConclusionMicroneurosurgery for VA anomalies in refractory VBI patients, particularly those with concomitant parkinsonian-like syndromes, has demonstrated potential in symptom remission and medication reduction.

Brain magnetic resonance imaging and computed tomography findings in cats and dogs with central nervous system cryptococcosis in Australia: 23 cases (2009-2020).

To describe the imaging findings in Australian cats and dogs with CNS cryptococcosis. 23 cases (10 cats; 13 dogs) with CNS cryptococcosis and brain MRI or CT studies available to review. Retrospective, multi-institutional case series. Brain MRI or CT studies were reviewed by a board-certified radiologist. Imaging findings were described and the differences between cats and dogs explored. Morphologic features were consistent with extra-axial lesions in all (n = 13) dogs and either intra-axial (5/10) or extra-axial (4/10) lesions in cats, with 1 cat having no detectable lesions in low-field brain MRI scans. Meningeal abnormalities were most common, followed by forebrain and cerebellar lesions. Intracranial MRI lesions were typically T2 hyperintense and T1 hypo- to isointense. Four cases had T2 hypointense lesions affecting the brain, sinonasal cavity, or regional lymph nodes. Intracranial CT lesions were mostly soft tissue attenuating. Contrast enhancement was present in all cases with contrast series available, with ring enhancement shown only in cats. Osteolysis was more common in dogs than cats, particularly affecting the cribriform plate. All 13 dogs and many (6/10) cats had at least 1 lesion affecting sinonasal or contiguous tissues, and locoregional lymphadenomegaly was common (7/10 cats; 11/13 dogs). Imaging lesions in cryptococcal meningoencephalitis were extra-axial in dogs but could be intra-axial or extra-axial in cats. Careful examination for extracranial lesions (sinonasal, retrobulbar, facial soft tissue, tympanic bullae, or locoregional lymph nodes) is important to provide alternative safe biopsy sites. T2 hypointense lesions, while rare, should prompt consideration of cryptococcosis.

Dizziness Evaluation and Characterisation of Patients with Posterior Circulation Stroke in the Emergency Department; a Case Series Study.

Dizziness is a common scenario in the Emergency Departments (EDs). Among dizziness underlying causes, the posterior circulation stroke is especially relevant due to its mobimortality and concerning misdiagnosis rates. Therefore, we conducted this study to assess dizziness evaluation and baseline characteristics of patients with PS in the ED. We conducted a 3-year retrospective observational study on PS cases confirmed by magnetic resonance imaging (MRI). Concretely, we analysed the demographic profile of these patients, the initial PS clinical presentation, and diagnostic workup (with emphasis on dizziness evaluation) performed at the ED. During the study period, 85 cases were registered. Risk factors for cardiovascular disease were present in 85.5% and previous visits to the ED due to dizziness were recorded in 16.5%. The main clinical presentation was dizziness, concretely as an acute vestibular syndrome (38.8%) with additional neurological signs or symptoms (80%). Evaluation by the otolaryngologist on call was requested in less than 10% of the cases and included the HINTS protocol use with a sensitivity of 100% for central nervous system underlying causality. A brain CT study was always performed with a sensitivity of 27%. However, 96.47% of patients were primarily admitted to the Neurology hospitalization ward and MRI was always performed in a mean time of 3.21 days confirming the diagnosis. Dizziness is the most frequent symptom of PS. Patients usually present an AVS (associated with additional N-SS or not) and HINTS bedside examination is the most adequate protocol to differentiate a PS from other AVS causes until the diagnostic confirmation via MRI. Interestingly, mainly otolaryngologists seem to use HINTS. However, the use of CT is widespread despite its poor value.

Brain CT requests from emergency department: Reality

ObjectivesTo evaluate the most common reasons for requesting brain CT studies from the emergency department and to calculate the prevalence of urgent acute pathology on this population group. Material and methodsWe reviewed brain CT studies requested from the emergency department during October and November 2018. We recorded the following variables: age, sex, reason for requesting the study, CT findings, use of contrast agents and reasons for using them, and, in patients who had undergone previous head CT studies, whether the findings had changed. SPSS was used for statistical analyses. ResultsA total of 507 urgent brain CT studies were done (41.4% in men, 58.6% in women; mean age, 65.4±20 years).The most common reason for requesting the study was head trauma (40.5%); only 15.6% of these studies showed acute posttraumatic intracranial lesions.The second most common reason was focal neurologic symptoms (16%); only 16% of these studies showed recent ischemic infarcts or acute bleeding.No pathological findings were reported in 43.2% of the studies.The most common abnormal finding was ischemic lesions in small vessels (20%).Space-occupying lesions (both benign and malignant) were found in 3.9% of all patients. ConclusionsMost brain CT studies requested from the emergency department showed no findings that would modify the management of the patient. Overuse of urgent brain CT increases the radiology department’s workload and exposes patients to radiation unnecessarily.

Birth-related subdural hemorrhage: prevalence and imaging morphology.

Birth trauma accounts for 1-2% of the mortality in newborns with significant intracranial injuries presenting in the immediate postnatal period. However, a significant number of asymptomatic neonates harbor birth-related intracranial hemorrhage (ICH), with birth-related subdural hemorrhage (SDH) being a common occurrence on infant brain CT and MRI studies performed as a standard of care for a variety of reasons. Although clinically insignificant, birth-related SDH is frequently brought up in courts as an alternative explanation for SDH in suspected abusive head trauma. The aim of this study was to determine prevalence, imaging morphology and distribution of birth-related SDHs on brain CT and MRI studies obtained as a standard of care in infants up to 1month old. We further tried to ascertain the relationship of birth-related SDHs with mode of delivery and birth weight. Infants up to the age of 1month who had CT or MRI of the brain performed between Jan. 1, 2018, and March 29, 2020, were included in this retrospective observational study. In addition to the imaging data, we reviewed clinical history, birth history including birth weight and mode of delivery, and final diagnoses. Two hundred six infants younger than 30days (range 0-29days, mean 11.9days, median 11days and standard deviation [SD] 8.4days) had a CT or MRI study during the study period. Among these, 58 infants were excluded as per the exclusion criteria. Among the included 148 infants, 88 (59.5%) had no imaging evidence of SDH. An additional 56 (37.8%) infants were assessed as having birth-related SDH based on review of clinical data. Within the birth-related SDH cohort (56 infants), only supratentorial SDH was identified in 5 (8.9%), only infratentorial SDH was identified in 14 (25%), while SDHs within both compartments were identified in 37 (66.1%) infants. The most common location for supratentorial birth-related SDH was along the occipital lobes (31/42, 73.8%), with other common locations being along the posterior interhemispheric fissure (30/42, 71.4%) and fronto-parietal convexity (9/42, 21.4%). The distribution of posterior fossa SDH was along the tentorium (38/51, 74.5%), along the cerebellum (38/51, 74.5%) and in both the locations (25/51, 49.0%). The rate of SDH was significantly higher in vaginal delivery group (46/84, 54.7%) as compared to caesarean section group (10/57, 17.5%) (P<0.05). We did not find any statistically significant difference between the birth weights of normal and birth-related SDH cohorts (P>0.05). Birth-related SDH is a common occurrence, with our study suggesting a prevalence of 37.8%. The most common distribution of birth-related SDH is within both the supra- and infratentorial compartments (66.1%) followed by infratentorial compartment (25%). The rate of birth-related SDH was significantly higher in vaginal delivery group as compared to caesarean section group.

Tomografía computarizada cerebral solicitada desde Urgencias: la realidad

ObjectivesTo evaluate the most common reasons for requesting brain CT studies from the emergency department and to calculate the prevalence of urgent acute pathology on this population group. Material and methodsWe reviewed brain CT studies requested from the emergency department during October and November 2018. We recorded the following variables: age, sex, reason for requesting the study, CT findings, use of contrast agents and reasons for using them, and, in patients who had undergone previous head CT studies, whether the findings had changed. SPSS was used for statistical analyses. ResultsA total of 507 urgent brain CT studies were done (41.4% in men, 58.6% in women; mean age, 65.4±20 years).The most common reason for requesting the study was head trauma (40.5%); only 15.6% of these studies showed acute posttraumatic intracranial lesions.The second most common reason was focal neurologic symptoms (16%); only 16% of these studies showed recent ischemic infarcts or acute bleeding.No pathological findings were reported in 43.2% of the studies.The most common abnormal finding was small vessel disease (20%).Space-occupying lesions (both benign and malignant) were found in 3.9% of all patients. ConclusionsMost brain CT studies requested from the emergency department showed no findings that would modify the management of the patient. Overuse of urgent brain CT increases the radiology department's workload and exposes patients to radiation unnecessarily.

Abstract 20: Deep Learning-Based Automated Intracranial Hemorrhage Detection and Notification

Introduction: Ruling out hemorrhage (stroke or traumatic) prior to administration of thrombolytics is critical for Code Strokes. A triage software that identifies hemorrhages on head CTs and alerts radiologists would help to streamline patient care and increase diagnostic confidence and patient safety. ML approach: We trained a deep convolutional network with a hybrid 3D/2D architecture on unenhanced head CTs of 805 patients. Our training dataset comprised 348 positive hemorrhage cases (IPH=245, SAH=67, Sub/Epi-dural=70, IVH=83) (128 female) and 457 normal controls (217 female). Lesion outlines were drawn by experts and stored as binary masks that were used as ground truth data during the training phase (random 80/20 train/test split). Diagnostic sensitivity and specificity were defined on a per patient study level, i.e. a single, binary decision for presence/absence of a hemorrhage on a patient’s CT scan. Final validation was performed in 380 patients (167 positive). Tool: The hemorrhage detection module was prototyped in Python/Keras. It runs on a local LINUX server (4 CPUs, no GPUs) and is embedded in a larger image processing platform dedicated to stroke. Results: Processing time for a standard whole brain CT study (3-5mm slices) was around 2min. Upon completion, an instant notification (by email and/or mobile app) was sent to users to alert them about the suspected presence of a hemorrhage. Relative to neuroradiologist gold standard reads the algorithm’s sensitivity and specificity is 90.4% and 92.5% (95% CI: 85%-94% for both). Detection of acute intracranial hemorrhage can be automatized by deploying deep learning. It yielded very high sensitivity/specificity when compared to gold standard reads by a neuroradiologist. Volumes as small as 0.5mL could be detected reliably in the test dataset. The software can be deployed in busy practices to prioritize worklists and alert health care professionals to speed up therapeutic decision processes and interventions.

Same-Day Sinus and Brain CT Imaging in the Medicare Population: Are Practice Patterns Changing in Association with Medicare Policy Initiatives?

Monitoring the frequency of same-day sinus and brain CT (Outpatient Measure 14, "OP-14") is part of a recent large Centers for Medicare and Medicaid Services hospital outpatient quality initiative to improve imaging efficiency. This study investigates patient-level claims data in the Medicare population focusing on where same-day sinus and brain CT imaging is performed and how the frequency of same-day studies changed with time before and during OP-14 measure program implementation. Research Identifiable Files were used to identify all sinus and brain CT examinations from 2004 through 2012 for a 5% random patient sample of Medicare fee-for-service beneficiaries. Overall and site of service use rates were calculated for same- and non-same-day examinations. Changes were mapped to policy initiative timetables. The number of same-day sinus and brain CT studies from 2004 to 2012 increased 67% from 1.85 (95% CI, 1.78-1.91) per 1000 Medicare beneficiaries in 2004 to 3.08 (95% CI, 3.00-3.15) in 2012. The biggest driver of increased same-day studies was the emergency department setting, from 0.56 (95% CI, 0.53-0.60) per 1000 to 1.78 (95% CI, 1.72-1.84; +215.7%). Overall use of brain CT from 146.0 (95% CI, 145.1-146.9) per 1000 to 176.3 (95% CI, 175.4-177.2; +21%) and sinus CT from 12.6 (95% CI, 12.4-12.8) per 1000 to 15.4 (95% CI, 15.2-15.6; +22%) increased until 2009 and remained stable through 2012. Previously increasing same-day sinus and brain CT in Medicare beneficiaries plateaued in 2009, coinciding with the implementation of targeted measures by the Centers for Medicare and Medicaid Services. Same-day imaging continues to increase in the emergency department setting.

Clinical and neuroimaging characteristics of patients with hereditary diffuse leukoencephalopathy with spheroids (HDLS)

Hereditary diffuse leukoencephalopathy with spheroids (HDLS) is an autosomal dominant early-onset dementia that affects the cerebral white matter predominantly. Mutations in colony stimulating factor-1 receptor (CSF-1R) were identified as the genetic cause of HDLS, and this enabled the antemorterm diagnosis of HDLS by genetic testing. This review paper describes clinical and neuroimaging findings in genetically-proven HDLS cases. The mean age at onset was 45 years ranging from 18 to 78 years. The most frequent initial symptom was cognitive decline. A wide range of clinical features including intellectual decline, behavioral and character changes, convulsion, pyramidal signs and motor symptoms have been described. Series of brain MRI study exhibit the white matter changes on FLAIR images, which were occasionally asymmetric in the early phase of the disease. Early MRI features are alteration of corpus callosum and dilatation of lateral ventricles showing central atrophy. Hyperintensity lesions detected by diffusion weighted images were detectable in some cases with HDLS. Brain CT study showed spotty calcification in the affected white matter. HDLS is not rare disease and should be considered as differential diagnosis of early-onset dementia exhibiting the white matter disease.

Intraventricular silicone oil

The authors report a case in which intravitreous silicone oil migrated into the ventricles. They note that intraventricular silicone oil can be misdiagnosed as intraventricular hemorrhage and neurosurgeons should be aware of this possibility. This 58-year-old woman with a history of Type II diabetic mellitus and retinal detachment (resulting from diabetic retinopathy), which had been treated with intravitreous silicone tamponade, presented with dizziness and headache approximately 10 years after the intravitreous silicone treatment. Over the next 6 years she underwent 2 non-contrast-enhanced brain CT studies and 1 MRI study for evaluation of her symptoms. On CT scan, extension of the intraocular silicone along the optic nerve was evident. Two hyperdense nodules were observed freely floating in the right lateral and fourth ventricles, remaining in the nondependent portion of ventricles in both supine and prone positions. On T2-weighted MRI, the left orbital content and the intraventricular nodules all demonstrated chemical shift artifacts typically associated with silicone. The imaging findings were characteristic for intraventricular silicone after silicone oil tamponade. The patient's dizziness and headache were treated symptomatically and she was followed up at the outpatient department. Migration of intravitreous silicone oil into the cerebral ventricles is a rare complication. Intraventricular silicone oil can mimic intraventricular hemorrhage. Radiographically, intraventricular silicone oil can be distinguished from hemorrhage as silicone oil tends to stay in the nondependent portion of the ventricle. Chemical shift artifacts on MRI may help establishing the diagnosis of intraventricular silicone oil. Currently, there is no consensus on surgical removal of intraventricular silicone oil, and in the majority of cases reported in the literature, the patients were asymptomatic.

Quality Outcomes of Reinterpretation of Brain CT Studies by Subspecialty Experts in Stroke Imaging

The purposes of this study were to determine the clinical importance and relative value of reinterpretation of brain CT studies by subspecialty experts by assessing the accuracy of interpretation by general radiologists at primary stroke centers and to assess interpretive quality outcomes as a function of change in the treatment of patients with stroke diagnoses or acute presentations of suspected stroke. Computerized medical records for the years 2009-2010 at four major community hospitals were queried for primary interpretation of brain CT studies of stroke patients with an acute presentation of either stroke or suspected stroke as diagnosed by board-certified general radiologists (nonneuroradiologists). A central database was queried that allowed one to query by clinical history or symptoms. Secondary interpretation of images of the identified patient sample was then performed by three experienced neuroradiologists. Each case was initially interpreted as an emergency or urgent study by a general radiologist. The reinterpretations performed by a neuroradiologist were scored as concordant or discordant. The discordant studies were categorized as a major discordance if there was a change in clinical management or as a minor discordance if there was no effect on or change in clinical management. The assessment was limited to brain CT studies without contrast administration. CT angiography and perfusion CT studies were not included in the analysis. Patients with hemorrhagic stroke, brain tumors, abscesses, and AIDS or HIV infection were excluded to limit the assessment to ischemic nonhemorrhagic disease. Of the 560 studies reviewed, 14 studies (2.5%) were identified as discordant. Of those discordant studies, four (0.7% of the original 560) were categorized as major discrepancies necessitating a change in clinical management. Ten (1.78%) were categorized as minor discrepancies, for which there was no change in management. There were no permanent adverse outcomes with respect to morbidity and mortality as a result of a discrepant interpretation, as determined by chart review or communication with the attending or referring physician by the secondary reader. Most of the interpreted head CT cases read by board-certified general radiologists for patients presenting with stroke or stroke symptoms did not result in discordant interpretations as verified by subspecialty experts. Discordant interpretations did not result in changes in clinical management in most cases. Double reading of head CT scans for these patients by subspecialty experts appears to be an inefficient method of substantially improving imaging health quality outcomes in stroke.

A comparative contrast perception phantom image of brain CT study between high-grade and low-grade liquid crystal displays (LCDs) in electronic medical charts

The purpose of this study was to clarify whether non-medical-grade liquid crystal displays (LCDs) are acceptable for the soft-copy reading of brain CTs. Four kinds of color LCDs with different image quality levels were used: medical-grade LCD, low-grade general LCD calibrated with the grayscale display function (GSDF), low-grade general LCD calibrated with gamma 2.2 and a notebook personal computer display panel. In Osirix’s standard window setting for brain CTs, the average CT values of brain parenchyma in 100 cases were correlated with a grayscale level ranging from 71 to 91 in a 256-step grayscale. At these gray levels, the image contrast on the two low-grade LCDs calibrated with gamma 2.2 was higher than that on the medical-grade LCD. Eleven healthy volunteers participated in the contrast perception study, which used electronically generated target phantom images that simulated subtle abnormalities with a low or high attenuation difference in brain parenchyma. The three low-grade LCDs showed correct response rates and reaction times that were superior to those of the medical-grade display. The grayscale calibrations, GSDF or gamma 2.2, are likely to be more critical than the display grade, suggesting that the use of a low-grade LCD may be acceptable in the image contrast of brain CT.

Diagnostic efficacy of handheld devices for emergency radiologic consultation.

Orthopedic injury and intracranial hemorrhage are commonly encountered in emergency radiology, and accurate and timely diagnosis is important. The purpose of this study was to determine whether the diagnostic accuracy of handheld computing devices is comparable to that of monitors that might be used in emergency teleconsultation. Two handheld devices, a Dell Axim personal digital assistant (PDA) and an Apple iPod Touch device, were studied. The diagnostic efficacy of each device was tested against that of secondary-class monitors (primary class being clinical workstation display) for each of two image types-posteroanterior wrist radiographs and slices from CT of the brain-yielding four separate observer performance studies. Participants read a bank of 30 wrist or brain images searching for a specific abnormality (distal radial fracture, fresh intracranial bleed) and rated their confidence in their decisions. A total of 168 readings by examining radiologists of the American Board of Radiology were gathered, and the results were subjected to receiver operating characteristics analysis. In the PDA brain CT study, the scores of PDA readings were significantly higher than those of monitor readings for all observers (p < or = 0.01) and for radiologists who were not neuroradiology specialists (p < or = 0.05). No statistically significant differences between handheld device and monitor findings were found for the PDA wrist images or in the iPod Touch device studies, although some comparisons approached significance. Handheld devices show promise in the field of emergency teleconsultation for detection of basic orthopedic injuries and intracranial hemorrhage. Further investigation is warranted.

Novel locus for benign hereditary chorea with adult onset maps to chromosome 8q21.3 q23.3

Autosomal dominant choreas are genetically heterogeneous disorders including Huntington disease (HD), Huntington disease like 1 (HDL1), Huntington disease like 2 (HDL2), dentatorubro-pallidoluysian atrophy (DRPLA), spinocerebellar ataxia type 17 (SCA17) and benign hereditary chorea (BHC). We identified two Japanese families with adult-onset benign chorea without dementia inherited in an autosomal dominant pattern. All affected individuals presented slowly progressive choreic movements in their upper and lower extremities, trunk and head with an age of onset ranging from 40 to 66 (average 54.3), which were markedly improved by haloperidol. The affected individuals also developed reduced muscle tones in their extremities. The findings obtained in the brain CT or MRI studies of nine affected individuals were normal. These clinical features resemble those of the so-called 'senile chorea'. HD, HDL1, HDL2, DRPLA, SCA17 and BHC caused by mutations in the TITF-1 gene were excluded by mutational and linkage analyses. A genome-wide linkage analysis revealed linkage to chromosome 8q21.3-q23.3 with a maximum cumulative two-point log of the odds (LOD) score of 4.74 at D8S1784 (theta = 0.00). Haplotype analysis of both the families defined the candidate region as 21.5 Mb interval flanked by M9267 and D8S1139. We named this adult-onset dominant inherited chorea 'benign hereditary chorea type 2 (BHC2)'.

Síndrome de restauración inmune asociado a tratamiento antirretroviral y criptococosis meníngea: Caso clínico

The objective of high activity antiretroviral therapy (HAART) in patients with AIDS, is to obtain immune restoration. This means a reduction of the viral load and restitution of the CD4 cell count. A decreased rate of HIV replication improves both the number and function of CD4 cells. Nevertheless, this treatment sometimes results in the reappearance of previous symptoms from treated conditions due to opportunistic infections (ie: tuberculosis, criptococcosis, hepatitis, Pneumocystis jirovesi, toxoplasmosis, etc) or non infectious condition such as sarcoidosis, Graves disease or Kaposi sarcoma. This is known as Inflammatory Reconstitution Immune Syndrome (IRIS). We report a 37 year-old woman in stage C3-AIDS with a previous criptococcal meningitis. She was treated, achieving a marked improvement with treatment and subsequent suppressive therapy with fluconazole 200 mg/day. IRIS appeared after 8 months of ongoing antiretroviral therapy with immune restoration with the development of aseptic meningitis and intracranial hypertension. The opportunistic agent could not be identified by cultures. Additional laboratory tests excluded toxoplasmosis, tuberculosis, bacterial cerebral abscesses, syphilitic cerebral gummas, and lymphoma. Brain CT and magnetic resonance studies were compatible with brain vasculitis and leptomeningitis. The patient condition improved with general measures, such as a repeated lumbar punctures and non steroidal anti-inflammatory drugs. We conclude that this patient had an IRIS due to a Cryptococcus neoformans antigen.

Gray–white matter discrimination—a possible marker for brain damage in heat stroke?

Introduction/objective: Heat stroke (HS) is a common medical emergency which carries high morbidity and morality. This study was designed to describe the pattern of central nervous system (CNS) changes as detected by brain CT scan in a case series of six patients suffering from classical and exertional HS. Methods and patients: All the patients were admitted in critical condition during the heat wave in the summer of 1999 in Israel. Each was in deep coma with a measured core temperature of over 40 °C upon admission to the emergency department. Results: Aggressive cooling measures decreased the core temperature to <38 °C within 30 min following admission. Two patients (33.3%) died. One of the survivors remained in a vegetative state. Brain CT studies carried out within 4 days of admission in all the patients revealed severe loss of gray–white matter discrimination (GWMD) without signs of acute bleed or significant focal lesion, findings that persisted in repeated brain CTs in one patient who remained in a vegetative state. Discussion and conclusions: Loss of GWMD may represent an early and sensitive indication of severe brain damage in patients with severe HS. Further studies in larger groups of patients are warranted in order to determine whether the appearance of GWMD in brain CTs of patients with HS has prognostic value.

MAPD--an objective way to select mAs for paediatric brain CT.

CT is an advanced imaging modality, but the imaging parameters are normally selected subjectively. For standard head examinations, most of the parameters used are consistent amongst different centres, with the exception of large variations in the selection of the tube current-exposure time product (mAs). As a result, CT images may contain unacceptable levels of noise, or the patient may receive excessive radiation. In this study, the maximum anteroposterior diameter (MAPD) was shown to be a good criterion for mAs selection, and could be measured in a pilot view. 200 paediatric brain CT studies were randomly selected to determine the MAPD at the mid brain level. With knowledge of MAPD distribution, a phantom study was performed to determine the relationship between MAPD and the mAs required for consistent and acceptable image noise. It was found that the required mAs increased linearly with MAPD. Assuming the manufacturer's recommended value is "appropriate" for the average MAPD, the appropriate mAs value could be estimated. Using this method, appropriate mAs values were calculated retrospectively for a group of 240 randomly selected paediatric brain CT studies and compared with the actual mAs subjectively determined by the radiographer. Although their average values were similar, the difference between the calculated and actual values deviated markedly in some cases. When the actual mAs was smaller than the calculated value, higher image noise was observed. However, reduction of image noise was barely observed when the applied mAs was larger than the calculated value. Thus, this method is more objective and appropriate for determination of the mAs value for paediatric brain CT than the traditional subjective method.

Hypersomnia due to acute disseminated encephalomyelitis in a 5-year-old girl

A 5-year-old girl suffering from hypersomnia due to acute disseminated encephalomyelitis (ADEM) is reported. Brain CT revealed a large low-density lesion involving the lentiform nucleus, posterior limb of the internal capsule, thalamus, posterior hypothalamus and midbrain in the left side. She was treated with intravenous dexamethazone. After the initial dose of dexamethazone, hypersomnia was dramatically and rapidly improved. A later brain CT study disclosed that the lesion in the brain disappeared. The brain lesion in this case involved the waking center in the brain, which was described by Von Economo. We concluded that hypersomnia in this case was due to ADEM involving the neural mechanism for maintaing wakefulness, probably in the thalamus and posterior hypothalamus. Repeat all night polysomnograpy in this case disclosed prolonged total sleep time and increased amount of stage 3–4 sleep in the hypersomniac state.