Correlation Between Anterior–Posterior and Lateral Dimensions with the Effective and Water-Equivalent Diameters in Axial Images From Head Computed Tomography Examinations

Author(s):  
Winda Kusuma Dewi ◽  
Choirul Anam ◽  
Eko Hidayanto ◽  
Annisa Lidia Wati ◽  
Geoff Dougherty

Abstract The study aims to correlate the effective diameter (Deff) and water-equivalent diameter (Dw) parameters with anterior–posterior (AP), lateral (LAT) and AP + LAT dimensions in order to estimate the patient dose in head CT examinations. Seventy-four patient datasets from head CT examinations were retrospectively collected. The patient’s sizes were calculated from the middle slice using a software of IndoseCT. Dw and Deff were plotted as functions of AP, LAT and AP + LAT dimensions. The best trendline fit for LAT and AP functions was a second order polynomial, which resulted in R2 of 0.89 for Deff vs LAT, 0.88 for Dw vs LAT, 0.92 for Deff vs AP and 0.91 for Dw vs AP. A linear correlation was found for Deff vs AP + LAT, Dw vs AP + LAT and Dw vs Deff with R2 of 0.97, 0.96 and 0.98, respectively.


2021 ◽  
Vol 27 (3) ◽  
pp. 213-222
Author(s):  
Winda Kusuma Dewi ◽  
Choirul Anam ◽  
Eko Hidayanto ◽  
Arrum Nitasari ◽  
Geoff Dougherty

Abstract Purpose: The aim of this work was to establish the relationships of patient size in terms of effective diameter (Deff) and water-equivalent diameter (Dw) with lateral (LAT) and anterior-posterior (AP) dimensions in order to predict the specific patient dose for thoracic, abdominal, and pelvic computed tomography (CT) examinations. Methods: A total of 47 thoracic images, 79 abdominal images, and 50 pelvic images were analyzed in this study. The patient’s images were retrospectively collected from Dr. Kariadi and Kensaras Hospitals, Semarang, Indonesia. The slices measured were taken from the middle of the scan range. The calculations of patient sizes (LAT, AP, Deff, and Dw) were automatically performed by IndoseCT 20b software. Deff and Dw were plotted as functions of LAT, AP, and AP+LAT. In addition, Dw was plotted as a function of Deff. Results: Strong correlations of Deff and Dw with LAT, AP, and AP+LAT were found. Stronger correlations were found in the Deff curves (R2 > 0.9) than in the Dw curves (R2 > 0.8). It was found that the average Deff was higher than the average Dw in the thoracic region, the average values were similar in the abdominal and pelvic regions. Conclusion: The current study extended the study of the relationships between Deff and Dw and the basic geometric diameter LAT, AP, and AP+LAT beyond those previously reported by AAPM. We evaluated the relationships for three regions, i.e. thoracic, abdominal, and pelvic regions. Based on our findings, it was possible to estimate Deff and Dw from only the LAT or AP dimension.



Author(s):  
Keishin Kawamoto ◽  
Yasuhiro Fukushima ◽  
Akira Matsuda ◽  
Manabu Nakata

Abstract The purpose of this study was to investigate other indices estimating absorbed dose for eye lens and brain, using clinical images of East Asian pediatric patients. We simulated head computed tomography (CT ) examinations in 104 pediatric patients. Effective diameter (deff) and water equivalent diameter (dw) were measured on clinical images. Various size metrics and age were compared with absorbed dose normalised by CTDIvol (nD). The nD was estimated for eye and brain. The nD tended to decrease with advancing age. R2 between age and nD were 0.38 and 0.31 for eye and brain, respectively. Increasing head diameters decreased each nD. R2 between deff and dw, and nD were 0.20–0.24 and 0.51–0.53 for eye and brain, respectively. Head sizes allowed us to estimate absorbed dose in brain CT on East Asian pediatric patients. Scanning parameters for pediatric head CT may need to be based on individual patient information.



2019 ◽  
Vol 10 (02) ◽  
pp. 207-211
Author(s):  
Rajneesh K. Patel ◽  
Amit Kumar Choubey ◽  
Brijesh K. Soni ◽  
Rajeev Sivasankar ◽  
Vikash Chauhan

ABSTRACT Introduction: Emergency head computed tomography (CT) is rising exponentially during off working hours due to evidence-based medicine, patient’s expectation and desires, easy availability and apprehension of medico-legal cases, thereby raising health-care cost. There is huge gap in demand and supply of radiologist, especially during off working hours. There is need to know the pattern of emergency head findings. Materials and Methods: A retrospective analysis of all emergent noncontrast CT head during off working hours in the Department of Radiodiagnosis of a Tertiary Care Hospital, Mumbai, India, which were performed from June 2017 to May 2018. CT findings of 308 patients were analyzed. Results: About 63.6% of total head CT showed no significant abnormality. The most common abnormality was intracranial hemorrhage which was just 9.1% followed by acute infarct which was 6.2%. Extradural hemorrhage, subdural hemorrhage, and subarachnoid hemorrhage was only 1% each of total head CT findings. No significant abnormality was detected in 74.65%, 70.21%, 89.13%, 31.37%, 100%, and 69.09% in cases of head injury, seizure, giddiness/dizziness/syncope, cerebrovascular accident, transient ischemic attack, and altered sensorium, respectively. Conclusion: Pattern analysis of emergent head CT reveals that most of the emergent CT head shows no significant abnormality. There is a need for stringent guidelines for emergent head CT, training of emergency physician as well as CT technician for common findings to bridge the radiologist demand-supply gap for providing effective health care in peripheral hospitals.



2020 ◽  
Vol 188 (4) ◽  
pp. 464-469 ◽  
Author(s):  
Nika Zalokar ◽  
Nejc Mekiš

Abstract This study aimed to investigate the dose to the breasts during head computed tomography (CT) if lead shielding is used. The study was performed in two major hospitals using helical and axial protocols on an anthropomorphic phantom. Measurements were performed with and without the use of a lead shield of 0.5 mm equivalent density. The results showed a significant decrease in dose with the lead shielding in both hospitals. During the helical protocol, the use of shielding significantly reduced the dose by 96% in Hospital A and 82% in Hospital B. The dose reduction during axial protocol was also significant: 95% in Hospital A and 86% in Hospital B with lead shielding. Considering the significant dose reduction of 82% up to 96% during this study, we highly recommend the shielding of breasts regardless of the protocol used during head CT examinations.



2021 ◽  
Vol 94 (1117) ◽  
pp. 20200473
Author(s):  
Dimitris Mihailidis ◽  
Virginia Tsapaki ◽  
Pelagia Tomara

Objectives: The American Association of Physicists in Medicine (AAPM) Task Groups (TG) 204 and 220 introduced a method to estimate patient dose by introducing the Size-Specific Dose Estimate (SSDE). They provided patient size-specific conversion factors that could be applied to volumetric CT Dose Index CTDIvol to estimate patient dose in terms of SSDE based on either effective diameter (Deff) or water equivalent diameter (Dw). Our study presented an alternative method to manually estimate SSDE for the everyday clinical routine chest CT that can be readily used and does not require sophisticated computer programming. Methods: For 16 adult patients undergoing chest CT, the method employed an average relative electron density (ρelung = 0.3) for the lung tissue and a ρetissue of 1.0 for the other tissues to scale the lateral thickness and compute the effective lateral thickness on the patient’s axial image. The proposed method estimated a “corrected” Deff (Deffcorr) to replace Dw and compared results with TG220 and a second method proposed by Huda et al, for the same set of CT studies. Results: The results showed comparable behavior for all methods. There is overall agreement especially between this study and TG220. Largest differences were +13.3% and+15.9% from TG220 and Huda values, respectively. Patient size correlation showed strong correlation with the TG220 and Huda et al methods. Conclusions: A simple, quick manual method to estimate CT patient radiation dose in terms of SSDE was proposed as an alternative where sophisticated computer programming is not available. It can be readily used during any clinical chest CT scanning. Advances in knowledge: The paper is novel as it presents simple, quick manual method to estimate CT patient radiation dose in chest imaging. The process can be used as alternative in cases no sophisticated computer programming is available.



Circulation ◽  
2019 ◽  
Vol 140 (Suppl_2) ◽  
Author(s):  
Bradley J Petek ◽  
David E Hamilton ◽  
Lindsay G Panah ◽  
Philip E Dormish ◽  
Sean R Mendez ◽  
...  

Introduction: Head computed tomography (CT) is frequently performed in survivors of out-of-hospital cardiac arrest (OHCA). However, the clinical utility of routine, early head CT in these patients is not well understood. We sought to characterize the associations between findings on early head CT with presenting characteristics and outcomes in survivors of OHCA. Hypothesis: Presence of early intracranial swelling is associated with poor outcomes. Methods: This is a retrospective analysis from a multicenter cohort of 432 patients with non-traumatic OHCA between 2/1/17 through 4/1/19. Patients were included if they underwent head CT <24 hrs after return of spontaneous circulation. Head CT findings were based on reads performed by local radiologists. Intracranial swelling was defined as loss of gray-white matter differentiation, sulcal effacement, and/or cerebral edema. Underlying cause of OHCA was adjudicated by trained physicians. Baseline characteristics and outcomes were compared between those with and without intracranial swelling. Result: Early head CT (<24 hrs) was performed in 378 (87.5%) patients with OHCA. Intracranial swelling was present in 97 (25.7%) patients with early head CT, and 14 (3.7%) had evidence of intracranial hemorrhage (ICH, Table). Of the patients presenting with ICH, 3/14 (21.4%) had shockable rhythms, 7/14 (50%) had subarachnoid hemorrhage, and ICH was the adjudicated cause of arrest in 10/14 (71.4%) patients. Patients with intracranial swelling were younger, less likely to have presented with a shockable rhythm, cardiac etiology, and witnessed OHCA. They were more likely to have a suppressed EEG, anoxia on MRI, and were less likely to survive to hospital discharge. Conclusions: In survivors of non-traumatic OHCA, routine, early (<24 hrs) head CT identified ICH in 3.7% of patients, and ICH was the adjudicated cause of arrest in 2.6% of patients. Intracranial swelling was present in more than 1/4 of patients, and associated with poor outcomes.



2018 ◽  
Vol 51 (6) ◽  
pp. 366-371 ◽  
Author(s):  
Natacha Calheiros de Lima Petribu ◽  
Andrezza Christine Vieira Fernandes ◽  
Marília de Brito Abath ◽  
Luziany Carvalho Araújo ◽  
Felipe Reis Silva de Queiroz ◽  
...  

Abstract Objective: To describe head computed tomography (CT) findings in neonates with congenital Zika virus infection confirmed in cerebrospinal fluid. Materials and Methods: This was a study of 16 newborn infants who exhibited abnormal head CT findings during an outbreak of Zika virus infection. Those infants had the following features: brain imaging suggestive of congenital infection; brain calcifications and negative results on tests for other main infectious causes of primary microcephaly, namely toxoplasmosis, cytomegalovirus, rubella, and HIV; positivity for Zika virus on IgM antibody capture enzyme-linked immunosorbent assay in cerebrospinal fluid. Results: Decreased brain volume was observed in 13 (81.2%) of the infants. All of the infants showed cortico-subcortical calcifications, mainly located in the frontal lobe. In 15 neonates (93.7%), ventriculomegaly was observed. Colpocephaly was a common finding, being observed in 10 patients (62.5%). A prominent occipital bone was identified in 9 patients (56.2%). Conclusion: Our study proves that Zika virus infection can cause congenital brain damage, with or without microcephaly. Some predominant head CT findings in neonates with congenital Zika virus infection, although not pathognomonic, are strongly suggestive of a pattern.



2020 ◽  
Vol 191 (4) ◽  
pp. 400-408
Author(s):  
M Benmessaoud ◽  
A Dadouch ◽  
M Talbi ◽  
M Tahiri ◽  
Y El-ouardi

Abstract The purpose of this study was to establish the diagnostic reference levels (DRLs) for paediatric head computed tomography (CT) in Morocco and to assess the effective doses received during head CT examinations. The data of 1007 patients were collected retrospectively from Moroccan university children’s hospitals. The sample was classified per age group:&lt;1, 1–5, 5–10 and 10–15 years. The proposed DRLs were defined as 75th percentile of the distributions, which were in terms of CT dose index of 26.98, 28.88, 34.00 and 38.20 mGy and dose length product of 461.64, 540.06, 627.20 and 705.98 mGy.cm, respectively. The effective doses estimated were 3.6, 2.9, 2 and 1.79 mSv, respectively. The DRLs reported in Morocco were compared with those of other countries, which were based on the same age grouping method, including Thailand, Switzerland, Japan and the international DRLs. Our initiative via the determination of the first Moroccan diagnostic reference levels for paediatric head CT must be a starting point to spread this investigation towards other examinations and imaging modalities.



2017 ◽  
Vol 08 (01) ◽  
pp. 064-067 ◽  
Author(s):  
Rakesh Kumar Mishra ◽  
Ashok Munivenkatappa ◽  
Vasuki Prathyusha ◽  
Dhaval P. Shukla ◽  
Bhagavatula Indira Devi

ABSTRACT Background: Indication of a head computed tomography (CT) scan in a patient who remains conscious after head injury is controversial. We aimed to determine the clinical features that are most likely to be associated with abnormal CT scan in patients with a history of head injury, and who are conscious at the time of presentation to casualty. Materials and Methods: This is a prospective observation study of patients presented to casualty with history of head injury, and who were conscious, i.e., Glasgow Coma Scale (GCS) 15 at the time of evaluation. All patients underwent head CT scan. The CT scan was reported as abnormal if it showed any pathology ascribed to trauma. The following variables were used: age, gender, mode of injury (road traffic accident, fall, assault, and others), duration since injury, and history of transient loss of consciousness, headache, vomiting, ear/nose bleeding, and seizures. Logistic regression analysis was used to identify the clinical features that predicted an abnormal CT scan. Results: During the observation period, a total of 1629 patients with head injury were evaluated, out of which 453 were in GCS 15. Abnormal CT scan was present in 195 (43%) patients. Among all the variables, the following were found significantly associated with abnormal CT scan: duration since injury (>12 h) P < 0.001; vomiting odds, ratio (OR) 1.89 (1.23, 2.80), P < 0.001; and presence of any symptom, OR 2.36 (1.52, 3.71), P < 0.001. Conclusion: A patient with GCS 15 presenting after 12 hours of injury with vomiting or combination of symptoms has a significant risk of abnormal head CT scan.



2014 ◽  
Vol 80 (1) ◽  
pp. 43-47 ◽  
Author(s):  
Bellal Joseph ◽  
Moutamn Sadoun ◽  
Hassan Aziz ◽  
Andrew Tang ◽  
Julie L. Wynne ◽  
...  

Anticoagulation agents are proven risk factors for intracranial hemorrhage (ICH) in traumatic brain injury (TBI). The aim of our study is to describe the epidemiology of prehospital coumadin, aspirin, and Plavix (CAP) patients with ICH and evaluate the use of repeat head computed tomography (CT) in this group. We performed a retrospective study from our trauma registry. All patients with intracranial hemorrhage on initial CT with prehospital CAP therapy were included. Demographics, CT scan findings, number of repeat CT scans, progressive findings, and neuro-surgical intervention were abstracted. A comparison between prehospital CAP and no-CAP patients was done using χ2 and Mann-Whitney U test. A total of 1606 patients with blunt TBI charts were reviewed of whom 508 patients had intracranial bleeding on initial CT scan and 72 were on prehospital CAP therapy. CAP patients were older ( P < 0.001), had higher Injury Severity Score and head Abbreviated Injury Scores on admission ( P < 0.001), were more likely to present with an abnormal neurologic examination ( P = 0.004), and had higher hospital and intensive care unit lengths of stay ( P < 0.005). Eighty-four per cent of patients were on antiplatelet therapy and 27 per cent were on warfarin. The CAP patients have a threefold increase in the rate of worsening repeat head CT (26 vs 9%, P < 0.05). Prehospital CAP therapy is high risk for progression of bleeding on repeat head CT. Routine repeat head CT remains an important component in this patient population and can provide useful information.



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