Timing of brain computed tomography for predicting neurological prognosis in comatose cardiac arrest survivors: a retrospective observational study / 世界急诊医学杂志（英文）

@#BACKGROUND: To assess the association between relevant brain computed tomography (CT) parameters at different time and neurological prognosis in adult comatose survivors after cardiac arrest (CA). METHODS: A total of 94 CA patients who underwent early and late CT scans (within 24 h and 24 h to 7 d respectively after CA) between January 2018 and April 2020 were enrolled in this retrospective study. According to the Cerebral Performance Category (CPC) score at hospital discharge, the patients were divided into either a good outcome (CPC 1-2) group or a poor-outcome group (CPC 3-5). The grey-to-white matter ratio (GWR) and the proportion of cerebrospinal fluid volume (pCSFV) were measured. In predicting poor outcomes, the prognostic performance of relevant CT parameters was evaluated, and the comparison analysis (expressed as the ratio of parameters in late CT to those in the early CT) of different CT time was conducted. RESULTS: Totally 26 patients were in the good-outcome group, while 68 patients were in the poor-outcome group. The putamen density, GWR, and pCSFV in late CT were significantly lower in the poor-outcome group (P<0.05). The ratios of GWR and pCSFV in the poor-outcome group were significantly decreased according to comparison analysis of different CT time (P<0.05), while there was no significant difference in the ratio of putamen density. GWR-basal ganglia <1.18 in late CT showed the best predictive value. The ratio of pCSFV <0.98 predicted unfavorable neurological outcomes with a sensitivity of 65.9% and a specificity of 93.8% (P=0.001). CONCLUSIONS: Brain CT performed >24 h after CA may be a good choice as a neuroimaging approach to evaluating prognosis. To predict neurological prognosis, comparison analysis of different CT time can be used as another promising tool in comatose CA survivors.

Valores típicos de dosis para tomografía computada de cerebro en pacientes adultos / Typical dose values for brain computed tomography in adult patients

Resumen: Debido al aumento en el uso de la Tomografía Computada (TC), y en consecuencia, la probabilidad de generar un incremento progresivo de la dosis recibida por los paciente y su relación en el potencial riesgo de los efectos de las radiaciones ionizantes, es importante implementar el uso de niveles de referencia diagnóstico (DRLs) en TC, como herramienta fundamental dentro de un programa de control de calidad que permita la evaluación y optimización de las dosis entregadas a los pacientes según la tarea clínica deseada. Con el objetivo de establecer valores típicos de dosis en TC de cerebro en Clínica Bupa Reñaca, se estudió una muestra de 73 informes dosimétricos generados en un equipo TC Toshiba Aquilion 64, en términos de indicadores de dosis para TC: Índice de dosis en TC por volumen (CTDIvol) y Producto dosis longitud (DLP). Con los datos obtenidos, se estimó el valor del percentil 50 (p50) para cada indicador de dosis, y se determinaron los valores típicos de dosis en cada grupo estudiado según sexo, edad e indicación clínica. Se logró definir y establecer una metodología que permitió la obtención de los valores típicos de dosis para TC de cerebro, optimizando las dosis sin producir una disminución en la calidad de la imagen necesaria para nuestro propósito clínico.

Abstract: Due to the increase in the use of Computed Tomography (CT), and consequently, the probability of generating a progressive increase in the dose received by the patient and its relationship in the potential risk of the effects of ionizing radiation, it is important to implement the use of diagnostic reference levels (DRLs) in CT, as a fundamental tool within a quality control program that allows the evaluation and optimization of the doses delivered to patients according to the desired clinical task. In order to establish typical dose values in brain CT at Bupa Reñaca Clinic, a sample of 73 dosimetric reports generated on a Toshiba Aquilion 64 CT unit was studied, in terms of dose indicators for CT: Dose rate on CT by volume (CTDIvol) and Dose Length Product (DLP). With the data obtained, the value of the 50th percentile (p50) for each dose indicator was estimated, and typical dose values were determined in each group studied according to sex, age and clinical indication. It was possible to define and establish a methodology that allowed obtaining typical dose values for brain CT, optimizing the doses without producing a decrease in the image quality necessary for our clinical purpose.

Evaluation of scatter radiation to the thyroid gland attributable to brain computed tomography scan in Port Harcourt, Nigeria

Background: Computed tomography (CT) is an axial imaging modality that uses X-ray. The study is to determine the amount of X-radiation that reaches the thyroid glands during brain CT.Methods: A prospective study was carried out in Rivers State University Teaching Hospital’s Radiology Department with 60 participants sent for brain CT scan. A 64 slice helical GE Optima CT machine was used while radiation dose reaching the thyroid gland was measured with themoluminiscent dosimeter (TLD) chips (TLD LiF-100). The TLD chip was placed on the anterior aspects of the neck at the level of 6th cervical vertebra (C6) and held in place with adhesive tapes. The TLD chip was later sent to the radiation dosimetric laboratory for reading. Collected data was analyzed using SPSS windows version 22.0 statistical software. A descriptive statistical tool was used to determine central tendencies. Pearson correlation and linear regression analysis models were also used to evaluate correlation between variables.Results: The mean (±SD) CTDI, DLP and brain Effective Dose were 37.265±13.098mGy, 662.451±230.782mGy-cm and 1.667±0.603mSv respectively. The Scatter X-Radiation reaching the thyroid gland and resultant Effective Dose were 5.26±3.13mSv and 0.26±0.16mSv respectively. A positive correlation between brain and thyroid gland effective doses yielded a Pearson’s correlation coefficient (r) of 0.892 within a confidence interval of 0.01 (p value of 0.01) showing significant correlation.Conclusions: The amount of radiation received by the thyroid gland during brain computed tomography scan is significant. Therefore, it is pertinent to protect the thyroid gland during the procedure.

The Effect of Brain Hemorrhage on the Prognosis of Out-of-Hospital Cardiac Arrest: a Retrospective Study

PURPOSE: Spontaneous intracranial hemorrhage (ICH) is not an uncommon cause of cardiac arrest. The purpose of this study was to identify the prognosis of patients with ICH for Out-of-Hospital Cardiac arrest (OHCA). METHODS: From January 2008 to December 2010, a total of 214 patients were checked brain computed tomography (CT) in OHCA. The majority of patients were male (136, 63.8%), and the median age was 55.0 (+/-16.7). We included all patients who were checked through brain CT for non-traumatic OHCA. Data were collected from electronic medical records and pre-hospital records. Demographic, clinical and laboratory data were compared between the ICH and non-ICH group. RESULTS: The detection of ICH by clinical manifestations and laboratory data was difficult. Out of 214 patients, 21 (9.8%) patients were positive for ICH and 193(90.2%) patients had a normal brain CT. In demographic and clinical data, the neurological outcome (CPC score, p=0.009) and 30-day survival rate (p<0.001) were statistically different between the two groups. Using the Cox proportional hazards model, the ICH group had a 3.54 hazard ratio compared with non-ICH group. In addition, pH (p=0.033), lactate (p=0.023) in ABGA, potassium (p=0.008), glucose (p=0.026), and S-100 (p=0.047) showed significant results. CONCLUSION: The prognosis of ICH patients in OHCA is poor; further studies are needed to improve the prognosis of ICH patients after ROSC in OHCA.

Factors Related to Subarachnoid Hemorrhage as a Cause of Out-of-Hospital Cardiac Arrest

PURPOSE: Subarachnoid hemorrhage (SAH) is a common cause of out-of-hospital cardiac arrest (OHCA). Early identification of patients with SAH induced OHCA may be helpful to emergency physicians when making therapeutic decisions. We conducted an investigation of the incidence and characteristics of patients with OHCA caused by non-traumatic SAH. METHODS: We conducted a retrospective review of cases of 236 OHCA survivors who had visited the emergency department (ED) of an urban tertiary care university hospital from January 2004 to December 2010. We excluded patients for whom there was an obvious cause or trauma. Clinical characteristics of SAH induced OHCA survivors were compared with those of SAH negative OHCA survivors. RESULTS: A total of 26 patients (19.11%) had been diagnosed with SAH. Compared with SAH negative survivors, SAH positive survivors were more likely to be female (odds ratio OR, 1.262; 95% confidence interval CI, 1.300-9.605), not to have Diabetes mellitus (OR, 0.180; 95% CI, 0.037-0.879), and to have a short duration of CPR time (OR, 1.074; 95% CI, 1.003-1.150). Results of the Cardiac Troponin T assay were less likely to be positive in patients with SAH induced OHCA, compared to those with SAH negative OHCA (OR, 0.071; 95% CI, 0.008-0.526). CONCLUSION: SAH is a more frequent cause of OHCA than originally believed. Immediate brain CT scan is useful in diagnosis of SAH when patient characteristics include: female, non diabetes mellitus, short duration of CPR time, or negative TnT.

Analysis of Radiological Findings in Ruptured Anterior Communicating Artery Aneurysms

In anterior communicating artery aneurysm that accounts for about 30% of intracranial aneurysms, it has been pointed out that the hemodynamic factor plays a very important role in all stages such as initiation, growth and rupture of aneurysm. Based upon the relationship between the findings of brain CT and those of cerebral angigram, the authors reviewed 96 cases of ruptured anterior communicating artery aneurysms that were operated on at the Department of Neurosurgery of Hanyang University Hospital from Jan. 1985 to June 1990, to suggest a point referred to which carotid artery should be selected first when direct carotid angiography is inevitable. The results were summarized as followings: 1) Of 96 cases, hemorrhagic evidence was observed in 92 case(95.8%) and among them, subarachnoid hemorrhage accompanying intracerebral hematoma(37 cases, 38.5%) was the most common type of hemorrhage. 2) Of 96 cases, left A1 was operated as afferent artery in 61 case(63.5%), right A1 in 23 cases(24.0%), and both A1, in 12 cases(12.5%). And the direction of aneurysm was to the right in 49 cases(51.0%), to the left in 12 cases(12.5%) and to the midline in 35 cases(36.5%). 3) Of 53 cases which had intracranial hematoma, 28 cases showed unilateral predominance. Among them the predominance of hematoma was opposite to the afferent artery in 82.1%(23/28) and was ipsilateral to the direction of aneurysm in 64.3%(18/28). 4) Of 91 cases which had subarachnoid hemorrhage, 29 cases showed unilateral predominance. Among them the predominance of hemorrhage was opposite to the afferent artery in 72.4%(21/29) and was ipsilateral to the direction of aneurysm in 58.6%(17/29). 5) Above findings suggest that in the cases with suspicious ruptured anterior communicating artery aneurysms on brain CT and direct carotid angiography is inevitable, contralateral carotid angiography should be undertaken at first when intracranial hematoma or subarachnoid hemorrhage shows unilateral predominance on brain CT, and left carotid antiography is preferable than the right one if there is no predominance of intracranial hematoma or subarachnoid hemorrhage on brain CT.

A Clinical study of the Intracranial Pressure Measurement by Use of a Fiberoptic Pressure Monitor

Continous monitoring of intracranial pressure can be one of the most inportant physical parameters in assesing patients who have or might develop intracranial hypertension. The authors has measured an intracranial epidural pressure by use of a Fiberoptic pressure monitor on 20 cases among brain damaged patients and evaluated it's effect by an epidural pressure change and Glasgow coma scale change after craniectomy and hypertonic solution infusion. Intracranial pressure was compared with signs of increased ICP on brain computed tomography. Also, complications were evaluated. The results are as follows ; 1) Average intracranial pressure was significantly decreased 48cmH2O during the first day after craniectomy. 2) Average intracranial pressure was significantly decreased 33cmH2O after infusion of 10% glycerol. 3) Improvement of the clinical states after craniectomy was not found in the cases above 20cmH2O in spite of decreasing intracranial pressure. 4) Sixteen of seventeen patients showing signs of increased intracranial pressure on brain computed tomography on admission developed elevated intracranial pressure. 5) The infection and intracranial hemorrhage were not found at the monitoring implement site three weeks after removing the intracranial pressure monitor.

Significance of Cranial Computed Tomography in Aneurysmal Subarachnoid Hemorrhage

The authors analysed 74 cases of ruptured aneurysms confirmed by CT, angiography and surgery during the period from September 1982 to August 1984 at Keimyung University Dongsan Hospital for the study of the relationship between the amount of subarachnoid hemorrhage(SAH) detected by CT and the preoperative clinical grade (Hunt & Hess), the later development of cerebral vasospasm, ischemic neurologic deficit(IND) and the postoperative prognosis. We also attempted to investigate the relationship between the low density in the hypothalamus and/or midbrain on CT and the preoperative clinical grade and the angiographic vasospasm. There was no definite difference in age and sex distribution according to the severity of SAH on CT except in predominantly female cases of severe SAH(CT grade III). 75% of the cases with the absence of SAH(CT grade I) were preoperatively clinical grade I or II. However, 76% of the severe SAH cases(CT grade III) showed preopertively clinical grade III, IV or V. In case with no angiographic vasospasm(Ag0), 70% were shown to be clinical grade I or II. But in cases of severe vasospasm seen by angiography(Ag3), 80% were clinical grade III or IV. 17% of the cases that showed an absence of angiographic vasospasm(Ar0) showed a low density in the hypothalamus and/or midbrain on CT as did 48% of the cases with mild angiographic vasospasm(Ag1), 75% with moderate angiographic vasospasm(Ag2) and 100% of the cases with severe angiographic vasospasm(Ag3). It was noticed on the CT in cases of clinical grade I and II, there was a 14% and 24% low density in the hypothalamus and/or midbrain respectively. But in the cases of clinical grade III and IV, it was noticed that there was a 65% and 100% low density in hypothalamus and/or midbrain respectively. Ischemic neurological deficit(IND) developed in 9% of the cases having an absence of SAH(CT grade I) on CT and in 48% of the cases of severe SAH(CT grade III) on CT during the care if the patients. 100% of the cases showed good postoperative results in patients who had an absence of or thin SAH(CT grade I or II) on CT and only 50% of the cases who had severe SAH(CT grade III) obtained good postoperative results. The authors found a correlation between the amount of SAH and the preoperative clinical grade, the development of angiographic cerebral vasospasm, IND and the postoperative prognosis. The low density in the hypothalamus and/or midbrain on CT also has a relationship with the preoperative clinical grade and the development of angiographic vasospsm. We suggest that the severity of SAH on CT and the low density in the hypothalamus and/or midbrain may be of great value in the prediction of cerebral vasospasm and treatment of aneurysmal patients.