Computed Tomography Scan Procedure Research Articles

A Novel Timing Equation for Predicting Optimal Contrast Medium Enhancement in Abdomen CT Scan Procedure

Abdominal CT (Computed Tomography) scans are crucial for diagnosing a wide range of abdominal conditions by providing detailed images of the abdominal organs. The aim of this study is to develop and validate a novel timing equation for predicting optimal contrast medium enhancement in abdominal CT procedures. Utilizing a quantitative research design, data was retrospectively collected from 155 patients who underwent CT scans with contrast media, focusing on variables such as age, gender, weight, creatinine levels, and injection parameters. Statistical analysis, including multi-linear regression and ANOVA, was conducted to derive predictive equations for arterial, venous, and delayed times. The results indicated that Location of the cannula significantly influence arterial time, age is significantly influence venous enhancement time, while weight was the only significant predictor of delayed time, demonstrating the need for patient-specific timing in CT scans. In conclusion, the proposed timing equation could enhance diagnostic accuracy and patient care by optimizing contrast enhancement in abdominal CT procedures.

Evaluation of fetal dose during pelvimetry CT scan procedure by Monte Carlo using GATE

Pelvimetry is performed at the late pregnancy to measure the size of the pelvis through its different diameters in order to determine the possible modalities of delivery: by natural way or by programmed cesarean section. When a pregnant woman undergoes a radiological examination, the risk associated with radiation exposure is of concern. In general, the fetal dose cannot be measured directly, so Monte Carlo (MC) methods are used for this purpose. Therefore the objective of this study is to evaluate the fetal dose during a Computed Tomography (CT) pelvimetry examination by means of a MC method using Geant4 Application for Tomographic Emission code (GATE). A simulation of a CT pelvimetry examination was performed by modeling a Hitachi Supria 16-slice scanner that follows a CT pelvimetry protocol. A 16-diameter phantom is used to model the fetus inside a 32-diameter phantom that represents the patient's body. The fetal dose in this simulation was 0.95 mGy. Other studies on fetal dose from pelvic CT scans found that it does not exceed a few mGys, which is not a real concern. On another hand, the dose showed a dependence on the variation of the tube current and also the voltage. Therefore, these parameters can be used as a basis for action to reduce exposure and limit risk during such examinations.

CT Scan: Is It Really Safe?

Excerpts:
 "It has often been said that there is no one more afraid of radiation than the radiologist. From Day 1 of residency training, radiologists-to-be are taught that excess radiation can cause cancer and a multitude of other medical conditions. After Hiroshima, Nagasaki and Chernobyl, history has shown that excess doses of radiation can cause cancer..."
 "The Computed Tomography (CT) Scan machine was invented in 19724 and used commercially soon thereafter. Since then, there was an incredible leap in the practice of medicine. Head injuries and trauma cases became routinely evaluated using CT. In recent years, CT has become the standard in screening for paranasal sinus disease, lung disease and coronary artery disease. Computed Tomography has become accessible and affordable. CT scan procedures are covered by health insurance in most First World countries..."
 [However, there are important questions which need to be raised:] "How much radiation does a patient receive with each CT Scan procedure? Should we be alarmed by the amount of radiation that a patient receives with each CT Scan procedure? Is the CT Scan really safe?"
 Unfortunately, it is not that easy to answer these questions. It is not ethical to do a randomized control study on the effect of radiation on humans by intentionally irradiating them without any expected benefits. We have to content ourselves with data on radiation doses obtained in previous studies."
 Read the complete article in the attached pdf...

Physicians’ knowledge about radiation protection of patients during prescription of CT scan procedures in Morocco

ObjectiveTo evaluate the knowledge and practices of Moroccan physicians in terms of radioprotection of patients when prescribing computed tomography (CT) procedures. MethodsThis is a cross-sectional study in which a questionnaire with 23 multiple-choice questions was sent to prescribers of CT examinations such as radiotherapists (RMs), other medical specialists (OMSs), general practitioners (GPs) and residents/interns (R/Is). The first eight questions asked about the demographics of the participants, while the remaining questions asked about knowledge of ionizing radiation examinations, doses received, relative risks, and patient radiation safety training. ResultsA total of 223 physicians participated in this survey. Radiation therapists, considered as the reference group, had a better knowledge of irradiating and non-irradiating imaging compared to the other groups (P ​= ​0.003). Thus, 67% of the reference group declared to take into account the number of scans performed by the patient during the last year, unlike the other groups (P ​= ​0.002). Furthermore, the knowledge of the different groups about the risks related to exposure to ionizing radiation was globally low (2%) (P ​= ​0.73). Regardless of their specialties and seniority, only 12% of the participants informed the patient at the time of prescription about the risks of X-rays. Finally, only 21% of the participants declared having had training in radiation protection, with no significant differences between the subgroups (P ​= ​0.832). ConclusionsThe results obtained are similar to those reported in previous studies. They show that Moroccan prescribers have a low level of knowledge of the risks associated with CT examinations. Training on patient radiation protection should be included in the initial curriculum of interns and the continuing professional development of physicians should be reinforced.

Future Perspective for Radiation Dose Reduction techniques in Computed Tomography - A Study

The Computed Tomography (CT) image quality is determining by appropriate radiation dose in CT examination. Increases of the radiation dose become dangerous for our health such as induces of cancer, skin injuries, heritable mutations, reddening, burn the skins, etc. Therefore, the dose management study in the CT scanning procedure is one of the most important factors. This research article focuses on the use of the dose effectively in pediatric CT and cardiac CT scan procedures. Besides, the paper comprises dose hunt-down, auditing the scanner utilization, patient safety for the hospital association. This research article discusses radiation dose reduction techniques for effective dose in the view of future perspective in CT scan. This research article suggesting an appropriate technique to reduce the dose effectively in CT images during scanning. The effective dose test was conducted after reviews and ideas from future perspective designs.

COVID-19 and COVID-like Patients: A Brief Analysis and Findings of Two Deceased Cases

BACKGROUND: The predominant pattern of lung lesions in patients affected by coronavirus disease (COVID-19) disease is diffuse alveolar damage with massive thromboembolism similar as described in patients infected with severe acute respiratory syndrome coronavirus and Middle East respiratory syndrome coronaviruses. Hyaline membrane formation and pneumocyte atypical hyperplasia were frequent. Importantly, the formation of platelet–fibrin thrombi in small vessels was seen consistent with coagulopathy, which appeared to be a common feature in patients who died of COVID-19. However, many were the cases found with similar COVID-19 symptomatology though negative results from nasal-pharyngeal swab performed by reverse transcription-polymerase chain reaction (RT-PCR). This latter typology of patients, otherwise named COVID-like, showed analogous clinical signs with similar arterial blood gas, cell blood count and laboratory parameters, and same computed tomography (CT)-scan ground-glass opacities. Symptoms such as cough, fever, and difficulty breathing were highly similar as well. Both forms, COVID-19 and COVID-like, are primarily respiratory with multi-organ involvement and both revealed comparable incubation periods often with a rapid onset and unexpected decay. 
 CASE REPORT: In this brief paper, we described two cases regarding two deceased males, one confirmed COVID-19 (RT-PCR but not CT scan) and the second a COVID-like (negative for RT-PCR but positive to CT scan with ground-glass opacity) whom condition, disease patterns, and analysis were highly similar.
 CONCLUSION: Improved investigation is mandatory, in which RT-PCR and CT scan procedures are completed by data from more detailed laboratory analysis, ABG analysis, BALF, and a deeper clinical assessment.

Establishing local Diagnostic Reference Level for Adult Patients in Computed Tomography Examination in Kohgiluyeh and Boyer-Ahmad province

Introduction: Nowadays, the absorbed dose of patients is on the rise due to the widespread use of computed tomography (CT) during the diagnosis process. Patients' doses for similar procedures are very different due to diversity in scanners and protocols. Hence, the purpose of this study was to determine the diagnostic reference levels for routine CT scan procedures in Kohgiluyeh and Boyer-Ahmad province, Iran. Material and Methods: In this study, four common brain, sinus, chest and abdominopelvic procedures (overall 200 scans) in spiral mode were selected in five CT centers of Kohgiluyeh and Boyer-Ahmad province, Iran. Next, the doses were measured in head and body phantom, based on scan parameters of ten patients in each procedure at each centers (200scans). Then, the third quartile of CTDIw was considered as the diagnostic reference dose. Finally, considering the pitch factor and the mean scan length in each protocol, the diagnostic reference level values based on the third quartile of the dose length product (DLP) and volume CTDI (CTDIvol) were determined. Results: The dose reference level values according to CTDIw third quartile in the brain, sinus, chest and abdominopelvic procedures were 39.82, 20.88, 14.10 and 17.07 mGy, respectively. In terms of dose length product, the diagnostic reference level values in the above procedures were determined to be 702.75, 243.90, 422.02, 865.62 mGy.cm, respectively. Conclusion: The DRLs of the CTDIW, DLP and CTDIvol of brain and sinus scans calculated in this study, were comparable to other provinces, national DRL and eight other countries. However, the same quantities for the chest and abdominopelvic scans showed higher values compared to the mentioned studies, suggesting lowering mAs and increasing pitch number for patient’s dose optimization. In some centers to preserve image quality, it is necessary to optimize radiation conditions, especially for chest and abdominopelvic scans.

A Modified Method Using Double Computed Tomography Scan Procedure to Maintain Mandibular Width in Mandibular Reconstruction.

The purpose of this study was to evaluate the use of a modified template system and double computed tomography scan procedure to maintain mandibular width in cases of mandibular reconstruction. Ten patients who underwent mandibular reconstruction with a fibular flap were enrolled. The surgeries were planned with a computer-aided surgical simulation (CASS) planning method. Following double computed tomography scan procedure, the template system was designed in a computer and was fabricated using a three-dimensional printing technique. The cutting guides were designed with the holes of the conventional reconstruction plate on the remnant mandibular segments. After surgery, the outcome evaluation was compared by first superimposing the post-operative computed tomography model onto the planned model and then measuring the differences between the planned and actual outcomes. All surgeries were completed successfully using the template system. With the use of the templates, the largest linear root-mean-square deviation (RMSD) between the planned and post-operative remnant segments was 1.01 mm, and the largest angular RMSD was 4.05°. The authors conclude that this template system and double computed tomography scan procedure provides a reliable method to maintain mandibular width in mandibular reconstruction using a fibular flap.

Effect of iodinated contrast media on serum electrolyte concentrations in patients undergoing routine contrast computed tomography scan procedure

Background and Objectives:Being hypertonic solutions, iodinated contrast media such as iohexol can cause a shift of fluids and electrolytes between different compartments of the body, but there is an ongoing discrepancy in data and current studies as to the effect of iodinated contrast media on serum electrolytes. Hence, this hospital-based prospective clinical observational study was carried out with objectives of evaluating the changes in serum electrolyte concentrations with intravenous iodinated contrast media administration in adult population and to correlate the changes in electrolyte concentrations, if any, with the demographic profile of the patients.Materials and Methods:We analyzed 103 numbers of adult patient samples over a period of 2 months by collecting blood both before administration of contrast and after 24 h of the contrast-enhanced computed tomography scan procedure. Serum concentrations of sodium, potassium, chloride, and ionized calcium were measured using Eschweiler Combiline analyzer based on ion-selective electrode principle.Results:The mean age of the study population in our study was 40.11 ± 20.51 years. We found that changes in serum sodium and chloride concentration after administration of contrast media are significant (sodium: 136.29 ± 3.53 vs. 132.49 ± 6.36 mmol/L and chloride: 100.03 ± 0.70 vs. 97.53 ± 0.70 mmol/L). Sodium concentration shows more decrease in females compared to males after administration of iodine contrast. The most probable reason for this decrease in serum electrolytes was secondary changes to hemodilution due to high osmolality of the contrast.Conclusions:Attending physicians must be alert for such possibilities of changes in electrolytes after contrast administration and be prepared to treat any adversity if one occurs.

Chromosomal Abnormalities in Human Lymphocytes after Computed Tomography Scan Procedure.

The incidence of chromosomal abnormalities and cancer risk correlates well with the radiation dose after exposure to moderate- to high-dose ionizing radiation. However, the biological effects and health risks at less than 100 mGy, e.g., from computed tomography (CT) have not been ascertained. To investigate the biological effects of low-dose exposure from a CT procedure, we examined chromosomal aberrations, dicentric and ring chromosomes (dic+ring), in peripheral blood lymphocytes (PBLs), using FISH assays with telomere and centromere PNA probes. In 60 non-cancer patients exposed to CT scans, the numbers of dicentric and ring chromosomes were significantly increased with individual variation. The individual variations in the increment of dicentric and ring chromosomes after CT procedures were confirmed using PNA-FISH analysis of PBLs from 15 healthy volunteers after in vitro low-dose exposure using a 137Cs radiation device. These findings strongly suggest that appropriate medical use of low-dose radiation should consider individual differences in radiation sensitivity.

Accuracy of a computed tomography scanning procedure to manufacture digital models.

Accurate articulation of the digital dental casts is crucial in orthodontic diagnosis and treatment planning. We aimed to determine the accuracy of manufacturing digital dental casts from computed tomography scanning of plaster casts regarding linear dimensions and interarch relationships and to test whether eventual differences in interarch relationships between plaster and digital casts would affect orthodontic diagnostics. Plaster casts with the wax bites of 2 patients were used to create digital dental casts with a computed tomography scanner. This was repeated 4 times with a 1-week interval. Linear distances were measured on plaster and digital models twice by 2 observers. Next, the 4 digital models of each patient were scored twice by 5 observers for interarch variables. Digital vs plaster measurements showed high Pearson correlation coefficients (>0.954), whereas the mean difference was small (<0.1mm) and not significant. The interarch scorings, however, showed significant differences for all variables, except overjet for model1. We found substantial interarch inaccuracies of the digital models. These inaccuracies are probably due to a lack of built-in "collision control" in the software and manual articulation of the digital models by a human operator.

Comparative evaluation of three different methods for evaluating alveolar ridge dimension prior to implant placement: An in vivo study

Background: During treatment planning for dental implant placement, there is a need for assessment of alveolar bone. Bone evaluation limited to the use of panoramic and or periapical radiographs may be insufficient, as it provides only two-dimensional information about the implant sites. Computed tomography (CT) provides three-dimensional information. The measurement of alveolar ridge dimensions can be accomplished using ridge-mapping technique. This technique involves penetrating the buccal and lingual mucosa down to the alveolar bone (following the administration of local anesthetic) with calipers and measures the bucco-lingual width of the underlying bone. Purpose: The aim of the study is to compare the techniques, i.e. ridge mapping, direct surgical exposure, and CT scan, which are used to measure the alveolar ridge bone width, and determine their accuracy in the clinical application. Materials and Methods: The study was conducted on 20 patients who reported to the Out-patient Department (OPD) of Prosthodontics and Crown and Bridge, PGIDS, Rohtak (Haryana) for replacement of edentulous span with dental implant. Width of alveolar ridge was studied by three techniques, i.e. CT scan procedure, ridge mapping, and direct surgical exposure at two points (3 mm from the crest of ridge and 6 mm from the crest of ridge), and then taking measurements of surgical exposure as the control group, the measurements obtained from the other two techniques were compared and then accuracy of these methods was assessed. The mean, standard deviation, standard error of mean, and degree of freedom were calculated and subjected to statistical analysis using Student's unpaired t test. Results: Results suggested that there is no significant difference in the measurements obtained by direct surgical exposure technique, ridge-mapping technique, and CT technique. Conclusion: Use of ridge-mapping technique along with panoramic and intraoral radiograph is adequate in cases where the pattern of resorption appears more regular and where mucosa is of more even thickness. It is suggested to use CT scan technique in situations where the alveolar ridges are resorbed, there is presence of maxillary anterior ridge concavities, vestibular depth is inadequate, and ridge mapping is not feasible.

Cost of Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) scan in UKMMC

Department of Radiology, Universiti Kebangsaan Malaysia Medical Centre (UKMMC), is one of the intermediate cost centres for ward and polyclinic. Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) scan are among the radiology investigations that consume high amount of resources. However, the actual cost of these procedures has never been properly imputed before. The charge for these procedures in UKMMC ranges from RM 550 - RM 800 and RM 100 - RM 450 for MRI and CT scan, respectively. These charges are lower as compared to private sectors and other teaching hospitals in Malaysia. Therefore, the aim of this study is to analyze the cost of MRI and CT scan procedures in UKMMC including the component cost that are involved in these procedures.

Prediction Value of the Canadian CT Head Rule and the New Orleans Criteria for Positive Head CT Scan and Acute Neurosurgical Procedures in Minor Head Trauma: A Multicenter External Validation Study

The New Orleans Criteria and the Canadian CT Head Rule have been developed to decrease the number of normal computed tomography (CT) results in mild head injury. We compare the performance of both decision rules for identifying patients with intracranial traumatic lesions and those who require an urgent neurosurgical intervention after mild head injury. This was an observational cohort study performed between 2008 and 2011 on patients with mild head injury who were aged 10 years or older. We collected prospectively clinical head CT scan findings and outcome. Primary outcome was need for neurosurgical intervention, defined as either death or craniotomy, or the need of intubation within 15 days of the traumatic event. Secondary outcome was the presence of traumatic lesions on head CT scan. New Orleans Criteria and Canadian CT Head Rule decision rules were compared by using sensitivity specifications and positive and negative predictive value. We enrolled 1,582 patients. Neurosurgical intervention was performed in 34 patients (2.1%) and positive CT findings were demonstrated in 218 patients (13.8%). Sensitivity and specificity for need for neurosurgical intervention were 100% (95% confidence interval [CI] 90% to 100%) and 60% (95% CI 44% to 76%) for the Canadian CT Head Rule and 82% (95% CI 69% to 95%) and 26% (95% CI 24% to 28%) for the New Orleans Criteria. Negative predictive values for the above-mentioned clinical decision rules were 100% and 99% and positive values were 5% and 2%, respectively, for the Canadian CT Head Rule and New Orleans Criteria. Sensitivity and specificity for clinical significant head CT findings were 95% (95% CI 92% to 98%) and 65% (95% CI 62% to 68%) for the Canadian CT Head Rule and 86% (95% CI 81% to 91%) and 28% (95% CI 26% to 30%) for the New Orleans Criteria. A similar trend of results was found in the subgroup of patients with a Glasgow Coma Scale score of 15. For patients with mild head injury, the Canadian CT Head Rule had higher sensitivity than the New Orleans Criteria, with higher negative predictive value. The question of whether the use of the Canadian CT Head Rule would have a greater influence on head CT scan reduction requires confirmation in real clinical practice.

The Use of Bedside Diagnostic Laparoscopy in the Intensive Care Unit

The clinical evaluation of the abdomen in intensive care (ICU) patients who are intubated can be very complex. Many bedside diagnostic tests are available to assist the clinician, including ultrasound, peritoneal lavage, and plain X-rays. However, in the ICU setting, these tests can be unreliable. An abdominal computed tomography (CT) scan is more reliable, but it requires transportation to the Radiology Department, which can be risky. In this paper, we present our experience with bedside laparoscopy in the general ICU population. Between April 2004 and November 2007, 35 adult patients (19 male, 16 female), with a mean age of 69 years (range, 39-83), underwent bedside diagnostic laparoscopy (DL) in the ICU. Hemodynamic and ventilatory parameters as well as the time required for the DL and CT scan procedure were compared. In addition, the ASA, APACHE II, and SOFA scores were documented. Laparoscopic findings were negative for intra-abdominal disease in 57.1% (n = 20) patients. The remaining patients (42.9%; n = 15) had positive laparoscopic findings for intra-abdominal disease. The overall mortality rate in our group of patients was 60%. The time required for DL was less (21.8 +/- 7.6 minutes) than the time required for a CT scan (38.2 +/- 6.2 minutes; P < 0.05). Three patients went on to have a therapeutic procedure in the ICU. The evaluation of the critically ill patient for intra-abdominal pathology with DL is a practical solution and needs to be used more frequently in this setting. In this paper, we present our experience with diagnostic laparoscopy in the ICU and found it to be safe and, in certain cases, may have a potential role as a bedside therapeutic tool. Although a number of reports with small series of patients have addressed the benefits and feasibility of DL, it is still being underutilized in the ICU. A more aggressive attempt should be made to incorporate DL as a routine procedure in the ICU.

The Use of a Wax Bite Wafer and a Double Computed Tomography Scan Procedure to Obtain a Three-Dimensional Augmented Virtual Skull Model

A detailed visualization of the interocclusal relationship is essential in a three-dimensional virtual planning setup for orthognathic and facial orthomorphic surgery. The purpose of this study was to introduce and evaluate the use of a wax bite wafer in combination with a double computed tomography (CT) scan procedure to augment the three-dimensional virtual model of the skull with a detailed dental surface. A total of 10 orthognathic patients were scanned after a standardized multislice CT scanning protocol with dose reduction with their wax bite wafer in place. Afterward, the impressions of the upper and lower arches and the wax bite wafer were scanned for each patient separately using a high-resolution standardized multislice CT scanning protocol. Accurate fitting of the virtual impressions on the wax bite wafer was done with surface matching using iterative closest points. Consecutively, automatic rigid point-based registration of the wax bite wafer on the patient scan was performed to implement the digital virtual dental arches into the patient's skull model (Maxilim, version 2.0; Medicim NV, St-Niklaas, Belgium). Probability error histograms showed errors of < or =0.16 mm (25% percentile), < or =0.31 mm (50% percentile), and < or =0.92 (90% percentile) for iterative closest point surface matching. The mean registration error for automatic point-based registration was 0.17 +/- 0.07 mm (range, 0.12-0.22 mm). The combination of the wax bite wafer with the double CT scan procedure allowed for the setup of an accurate three-dimensional virtual augmented model of the skull with detailed dental surface. However, from a clinical workload, data handling, and computational point of view, this method is too time-consuming to be introduced in the clinical routine.

Mass Screening of Multiple Abdominal Solid Organs Using Mobile Helical Computed Tomography Scanner—A Preliminary Report

The possibility of a new screening procedure for multiple abdominal solid organs using a mobile helical computed tomography (CT) scanner was evaluated. A total of 4,543 residents, who were 40 years of age or older, received CT scanning without contrast medium. The mean age of participants was 64 years including 2,022 males and 2,521 females. A total of 2,105 abnormal findings were uniquely detected in 1,594 participants. Liver and kidney diseases including ureter occupied around 30% of total abnormal findings, respectively. Besides frequent cystic or calcified lesions, solid tumours were suspected in 56 lesions, which received further examination by specialized physicians. Five (9%) of them were confirmed as being malignant tumours including pancreatic cancer in two patients, and liver, lung and ovary cancers in one patient each, respectively. All five patients with each malignant lesion received curative operations. Small-sized abdominal aortic aneurysms and heart valve diseases were uniquely found in 22 and two patients, respectively. Qualitative diagnoses of solid tumours were difficult using CT findings without contrast medium. CT screening procedures require further investigation in aspect of the selection of examinees, CT scanning procedure, sensitivity and specificity, and cost-effectiveness.

The use of a new 3D splint and double CT scan procedure to obtain an accurate anatomic virtual augmented model of the skull

Three-dimensional (3D) virtual planning of orthognathic surgery requires detailed visualization of the interocclusal relationship. The purpose of this study was to introduce the modification of the double computed tomography (CT) scan procedure using a newly designed 3D splint in order to obtain a detailed anatomic 3D virtual augmented model of the skull. A total of 10 dry adult human cadaver skulls were used to evaluate the accuracy of the automatic rigid registration method for fusion of both CT datasets (Maxilim™, version 1.3.0). The overall mean registration error was 0.1355 ± 0.0323 mm (range 0.0760–0.1782 mm). Analysis of variance showed a registration method error of 0.0564 mm ( P < 0.001; 95% confidence interval = 0.0491–0.0622). The combination of the newly designed 3D splint with the double CT scan procedure allowed accurate registration and the set-up of an accurate anatomic 3D virtual augmented model of the skull with detailed dental surface.

Utility of serial computed tomography imaging in pediatric patients with head trauma

The purpose of this study was to evaluate the risk of progression of traumatic intracranial lesions in children by comparing initial and subsequent computed tomography (CT) scans. Reserving repeated CT imaging for patients who harbor higher-risk lesions may reduce overall radiation exposure, the need for sedative agents, and cost. The authors performed a retrospective cohort study in 268 patients younger than 18 years of age who underwent repeated CT scanning within 24 hours of their initial CT scanning procedure. The risk of progression between the initial and repeated CT scanning sessions and the need for delayed neurosurgical intervention were determined for each lesion type. In 54 patients (20.1%) the normal findings on the initial CT study did not change on subsequent imaging. In 61 (28.5%) of the 214 patients in whom abnormal findings were present on the initial scan, progression was demonstrated. Patients with epidural hematoma (EDH; odds ratio [OR] 12.29), subdural hematoma (SDH; OR 3.18), cerebral edema (OR 9.34), and intraparenchymal hemorrhage (IPH; OR 18.3) were found to be at a significantly increased risk for progression and to require delayed neurosurgical intervention (OR 11.91). No significantly increased risk was found for patients with subarachnoid hemorrhage (SAH), intraventricular hemorrhage (IVH), diffuse axonal injury (DAI), or skull fracture. Repeated CT imaging in children with high-risk lesions such as EDH, SDH, cerebral edema, and IPH is recommended. However, in children with low-risk lesions, such as SAH, IVH, DAI, and isolated skull fractures but no sign of clinical deterioration, repeated imaging may be less likely to alter the clinical management scheme. The limited benefits of undertaking repeated imaging in these patients should be weighed against the risks of radiation exposure, sedation, intrahospital transportation, and patient monitoring.

P.290 The use of a modified wax bite and a double CT scan procedure to obtain an augmented model of the skull

This study evaluated different techniques for surgically assisted rapid maxillary expansion (SARME) according to the type of transverse maxillary deficiency using computed tomography (CT). Six adult patients with bilateral transverse maxillary deficiencies underwent SARME. The patients were equally divided into three groups: Group I, maxillary atresia in both the anterior and posterior regions; Group II, greater maxillary atresia in the anterior region; and Group III, increased maxillary atresia in the posterior region. In Group I, a subtotal Le Fort I osteotomy was used. In Group II, a subtotal Le Fort I osteotomy was used without pterygomaxillary suture disjunction. In Group III, a subtotal Le Fort I osteotomy was used with pterygomaxillary suture disjunction and fixation of the anterior nasal spine with steel wire. The midpalatal suture opening was evaluated preoperatively and immediately after the activation period using CT. For Group I, the opening occurred parallel to midpalatal suture; for Group II, the opening comprised a V-shape with a vertex on the posterior nasal spine; and for Group III, the opening comprised a V-shape with a vertex at the anterior nasal spine. The conclusion was that the SARME technique should be individualized according to the type of transverse maxillary deficiency.