Adult CT Examinations Research Articles

Comparison Between Manual Data Collection and the Dose Management System to Establish Local Diagnostic Reference Levels for Common Adult CT Examinations at Zayed Military Hospital

Comparison Between Manual Data Collection and the Dose Management System to Establish Local Diagnostic Reference Levels for Common Adult CT Examinations at Zayed Military Hospital

Patient radiation doses from adult CT examinations at the Souss Massa Regional Hospital

Objective: This study aimed to assess patient radiation doses, and to establish diagnostic reference levels for Adult CT examinations at the Souss Massa Regional Hospital, Morocco. Method: Data from 6 CT examinations were collected between January and June 2023 at the Souss Massa Regional Hospital, including patient age, sex, weight, and height, as well as scanner acquisition parameters such as the number of series, use of contrast media, rotation time plus slice thickness, the displayed Computed Tomography Dose Index (CTDIvol), and the Dose Length Product (DLP). Diagnostic reference levels (DRLs) were calculated for each type of CT examination by estimating the 75% percentile of CTDIvol and DLP. The effective dose is calculated using the following formula: E(mSv) = EDLP × DLP (mGy.cm). The data were statistically analyzed using SPSS version 21.0 software. Results: DRLs in terms of CTDIvol, and DLP for the brain without contrast media are 64,45 mGy, and 1405,77 mGy.cm respectively. For chest CT without contrast media, they are 11,13 mGy, and 417,73 mGy.cm respectively. The data from the abdominal CT show that the CTDIvol (9,74 mGy) and DLP (529,31 mGy.cm) values with contrast media are higher than those without contrast media, which are (9,35 mGy) and (515,21 mGy.cm) respectively. DRls in terms of CTDIvol and DLP for abdomen and pelvis (AP) CT with contrast media are 8,14 mGy and 444,51 mGy.cm respectively. For chest abdomen and pelvis (CAP) with contrast media they are 8,51 mGy, and 571,30 mGy.cm respectively. The effective doses were 2,37, 6,50, 6,24, 6,76, 5,07, 7,13 mSv for the brain without contrast media, chest without contrast media, abdomen without contrast media, abdomen with contrast media, AP with contrast media, and CAP respectively. Conclusion: Adapting CT protocols according to the morphology of patients and the conditions under which each examination is performed can help maintain the doses received by patients at an optimum level.

Cross-Check QA: A Quality Assurance Workflow to Prevent Missed Diagnoses by Alerting Inadvertent Discordance Between the Radiologist and Artificial Intelligence in the Interpretation of High-Acuity CT Scans

PurposeThe aim of this study was to implement and evaluate a quality assurance (QA) workflow that leverages natural language processing to rapidly resolve inadvertent discordance between radiologists and an artificial intelligence (AI) decision support system (DSS) in the interpretation of high-acuity CT studies when the radiologist does not engage with AI DSS output. MethodsAll consecutive high-acuity adult CT examinations performed in a health system between March 1, 2020, and September 20, 2022, were interpreted alongside an AI DSS (Aidoc) for intracranial hemorrhage, cervical spine fracture, and pulmonary embolus. CT studies were flagged for this QA workflow if they met three criteria: (1) negative results by radiologist report, (2) a high probability of positive results by the AI DSS, and (3) unviewed AI DSS output. In these cases, an automated e-mail notification was sent to our quality team. If discordance was confirmed on secondary review—an initially missed diagnosis—addendum and communication documentation was performed. ResultsOf 111,674 high-acuity CT examinations interpreted alongside the AI DSS over this 2.5-year time period, the frequency of missed diagnoses (intracranial hemorrhage, pulmonary embolus, and cervical spine fracture) uncovered by this workflow was 0.02% (n = 26). Of 12,412 CT studies prioritized as depicting positive findings by the AI DSS, 0.4% (n = 46) were discordant, unengaged, and flagged for QA. Among these discordant cases, 57% (26 of 46) were determined to be true positives. Addendum and communication documentation was performed within 24 hours of the initial report signing in 85% of these cases. ConclusionsInadvertent discordance between radiologists and the AI DSS occurred in a small number of cases. This QA workflow leveraged natural language processing to rapidly detect, notify, and resolve these discrepancies and prevent potential missed diagnoses.

Expanding the Concept of Diagnostic Reference Levels to Noise and Dose Reference Levels in CT.

OBJECTIVE. Diagnostic reference levels were developed as guidance for radiation dose in medical imaging and, by inference, diagnostic quality. The objective of this work was to expand the concept of diagnostic reference levels to explicitly include noise of CT examinations to simultaneously target both dose and quality through corresponding reference values. MATERIALS AND METHODS. The study consisted of 2851 adult CT examinations performed with scanners from two manufacturers and two clinical protocols: abdominopelvic CT with IV contrast administration and chest CT without IV contrast administration. An institutional informatics system was used to automatically extract protocol type, patient diameter, volume CT dose index, and noise magnitude from images. The data were divided into five reference patient size ranges. Noise reference level, noise reference range, dose reference level, and dose reference range were defined for each size range. RESULTS. The data exhibited strong dependence between dose and patient size, weak dependence between noise and patient size, and different trends for different manufacturers with differing strategies for tube current modulation. The results suggest size-based reference intervals and levels for noise and dose (e.g., noise reference level and noise reference range of 11.5-12.9 HU and 11.0-14.0 HU for chest CT and 10.1-12.1 HU and 9.4-13.7 HU for abdominopelvic CT examinations) that can be targeted to improve clinical performance consistency. CONCLUSION. New reference levels and ranges, which simultaneously consider image noise and radiation dose information across wide patient populations, were defined and determined for two clinical protocols. The methods of new quantitative constraints may provide unique and useful information about the goal of managing the variability of image quality and dose in clinical CT examinations.

Frequency of acute longus colli tendinitis on CT examinations

PurposeWe attempted to determine the frequency of acute longus colli tendinitis on diagnostic CT imaging performed at a large multicenter health care system. By correlating with the pre-imaging clinical information, we investigated which patient presentations should lead the radiologist to increased suspicion for this condition.MethodsImages from a total of 8101 adult CT examinations of the neck and cervical spine performed over a 3-month period were evaluated by researchers independent of the original clinical report. Clinical information available at the time of imaging was reviewed and assigned to one of five categories. Frequency of the condition was calculated by sex and clinical presentation. This retrospective study with waiver of consent and waiver of HIPPA was approved by our IRB.ResultsNine positive scans were found for an overall frequency of 1.1 per 1000 examinations. The frequency was significantly higher (11.4 per thousand) on scans performed of patients presenting without history of recent trauma, concern for tumor, suspected postoperative complication, or clinical signs of infection localized to the neck. Although frequency in males was higher than in females, this did not reach statistical significance. In no positive or negative case was longus colli tendinitis considered in the pre-imaging documentation.ConclusionsFindings of acute longus colli tendinitis on CT examination generally occur in the absence of prior mention of this condition in the medical record. The radiologist should be particularly alert for this diagnosis when a patient presents with rapid-onset neck pain without a clear history of recent trauma or other etiologies.

Indication-based diagnostic reference levels for adult CT-examinations in Finland.

A diagnostic reference level (DRL) is a predefined dose level, which should not be exceeded in an examination that is conducted appropriately on an average-sized patient. Since dose from only one examination should not be compared with a DRL, the average dose from a good sample of at least 10 average-sized patients should be compared. The previous DRLs for computed tomography (CT)-examinations for adults in Finland were issued in 2007 and only covered examinations conducted on a particular body region. Because the image quality requirements, and thus the dose needed, vary between different indications, there has been a call for indication-based DRLs for CT. The new indication-based DRLs for CT came into effect on June 2013. They are based on a dose survey performed in 2012. Doses were collected from examinations conducted on a particular body region, based on some indication and from some special examination types. The DRLs were set according to the third quartile approach. On average, the DRLs for a particular body region dropped ∼ 20 % from the previous DRLs.

Real practice radiation dose and dosimetric impact of radiological staff training in body CT examinations

ObjectivesTo evaluate the radiation dose of the main body CT examinations performed routinely in four regional diagnostic centres, the specific contribution of radiologists and technologists in determining CT dose levels, and the role of radiological staff training in reducing radiation doses.MethodsWe retrospectively evaluated the radiation dose in terms of dose-length product (DLP) values of 2,016 adult CT examinations (chest, abdomen-pelvis, and whole body) collected in four different centres in our region. DLP values for contrast-unenhanced and contrast-enhanced CT examinations performed at each centre were compared for each anatomical area. DLP values for CT examinations performed before and after radiological staff training were also compared.ResultsDLP values for the same CT examinations varied among centres depending on radiologists’ preferences, variable training of technologists, and diversified CT image acquisition protocols. A specific training programme designed for the radiological staff led to a significant overall reduction of DLP values, along with a significant reduction of DLP variability.ConclusionsTraining of both radiologists and technologists plays a key role in optimising CT acquisition procedures and lowering the radiation dose delivered to patients.Main messages The effective dose for similar CT examinations varies significantly among radiological centres.Staff training can significantly reduce and harmonise the radiation dose.Training of radiologists and technologists is key to optimise CT acquisition protocols.

A quantitative comparison of data evaluation methods to derive diagnostic reference levels for CT from a dosimetric survey: Correlation analysis compared to simple evaluation strategies

ObjectivesTo compare simple and sophisticated evaluation strategies for CT dosimetry surveys with focus on DRLs. MethodsBased on data from a nationwide Austrian CT dose survey, different evaluation strategies are compared. These were pooled data analysis, weight banding excluding data from patients with weights outside ±20 kg of the standard weights (70 and 75.6 kg representing the actual average weight), and a regression method estimating DLP probability distributions for the standard patient for each scanner before calculating quartiles. ResultsIn the abdomen and chest region, weight restriction (−9% and −4% around 70 and 75.6 kg, respectively, compared to pooled data analysis) and statistically weighting each scanner equally (−9%) have the largest effect on DRLs derived. However, the difference in 3rd quartiles calculated using weight restriction alone compared to regression analysis is relatively small (<1% for 70 ± 20 and −6% for 75.6 ± 20 kg, respectively, trunk region). In the head/neck region the effect of weight restriction is less than in for scans of the trunk (−1.3% and −0.2%, respectively); the most prominent changes resulted from excluding scanners with less than 10 patient cases (−5%), and equally weighting scanners rather than cases (−3%). ConclusionFor adult CT examinations (different to a paediatric survey), quite simple evaluation strategies yield results very comparable to those from sophisticated strategies.

Comparative evaluation of organ and effective doses for paediatric patients with those for adults in chest and abdominal CT examinations

Patient doses in paediatric and adult CT examinations were investigated for modern multislice CT scanners by using specially constructed in-phantom dose measuring systems. The systems were composed of 32 photodiode dosemeters embedded in various tissue and organ sites within anthropomorphic phantoms representing the bodies of 6-year-old children and adults. Organ and the effective doses were evaluated from dose values measured at these sites. In chest CT examinations, organ doses for organs within the scanning area were 2-21 mGy for children and 7-26 mGy for adults. Thyroid doses for children were frequently the highest with a maximum of 21 mGy. In abdominal CT examinations, organ doses for organs within the scanning area were 3-16 mGy for children and 10-34 mGy for adults. Effective doses evaluated for children and adults were found to be proportional to the effective mAs of CT scanners, where linear coefficients were specific to the types of CT examinations and to the manufacturers of CT scanners. Effective doses in paediatric chest CT and abdominal CT examinations were lower than those in adult examinations by a factor of two or greater on average for the same CT scanners because of the lower effective mAs adopted in paediatric examinations.

Overnight resident preliminary interpretations on CT Examinations: should the process continue?

We report our experience with resident preliminary interpretations given at night on both abdominal and neurological CT scans to quantify the discrepancy rate when compared to the final report. An attempt was also made to document any adverse clinical outcomes as a result of the preliminary interpretation. From January 1, 2004 to December 31, 2004, adult CT examinations were prospectively interpreted by residents at night at a level I trauma center. Both the neurological and body CT scans were reviewed beginning at 7:00 a.m. the following morning by the respective subspecialty staff and discrepancies were noted. Adult CT examinations (6,858) were prospectively interpreted by residents: 5,206 cranial spinal CT examinations and 1,652 body CT examinations. Among the neurological studies, there were six cases identified as major discrepancies (0.1%) and 185 minor discrepancies (3.5%). Among the body CT cases, there were seven cases identified as major discrepancies (0.4%) and 23 cases of minor discrepancies (1.4%). There is a low discrepancy rate (0.2% major and 3.1% minor) in the preliminary resident interpretations from the final report. The process of overnight preliminary CT interpretations should continue as it is not substandard care.