CT Protocol Research Articles

Analysis of image quality and radiation dose in routine adult brain helical and wide-volume computed tomography procedures

ObjectivesTo evaluate and compare image quality and radiation dose between the helical and wide-volume scans to determine the protocol that provides a lower radiation dose without loss in image quality. MethodsThe study was prospectively conducted on consented adult patients that presented for routine brain CT. Image quality and radiation dose were compared between the helical and wide-volume scans on the Toshiba 160-slice Aquilion Prime CT scanner. The volume computed tomography dose index (CTDIvol) and dose length product (DLP) for each scan mode were collected and compared. Image quality was quantitatively and qualitatively evaluated using the unenhanced brain CT images. The data were analysed using a statistical package for social sciences (SPSS) software version 20 for both the descriptive and inferential statistics. A significant difference in image quality and radiation dose between the helical and wide-volume scans was determined based on a p-value of <0.05. ResultsA total of 54 participants were included, with two groups of 27 participants. The CTDIvol and DLP values were significantly p < 0.05 higher in the helical scan (CTDIvol: 65 mGy; DLP: 1597 mGy.cm) compared to the wide-volume scan (CTDIvol: 54 mGy; DLP: 1133 mGy.cm). The grey and white matters show a better signal-to-noise ratio (SNR) for the helical scan. Meanwhile, the contrast-to-noise ratio (CNR) was significantly p < 0.05 higher in the wide-volume scan. The results from the visual grading methods were compared and showed superior image quality in helical over the wide-volume scan. ConclusionWide-volume provides a lower dose compared to helical and therefore, could be adopted as the routine protocol for brain CT for in house dose optimisation. Where clinical conditions warrant the need for a helical scan, the protocol should be optimised in line with the as low as reasonable achievable (ALARA) principle.

Image quality and radiation dose of dual source high pitch computed tomography in pediatric congenital heart disease

To explore the image quality and radiation dose of dual source high-pitch cardiac computed tomography with tailored contrast injection protocols for pediatric congenital heart disease patients (CHD). In total, 27 infants with CHD (median age 109 days [IQR 6–199]) were retrospectively analyzed regarding dose length product (DLP) and effective dose (ED) after undergoing cardiothoracic CT imaging. Scan parameters were adjusted on a dual source/detector CT (DSCT) to minimize radiation dose while maintaining adequate quality. Image acquisition was performed at 70% of the R–R interval. Dose reducing measures included prospective electrocardiogram gating, utilizing slow injection velocities and foregoing bolus tracking during contrast injection. Image quality was assessed for artefacts, vessel definition, and noise on a 5-point scale (1 non-diagnostic, 5 excellent). Series were scored on a 0-to-3-point scale regarding answered clinical questions (0 non-diagnostic, 3 all clinical questions could be answered). The median DLP was 5.2 mGy*cm (IQR 3.5–7.8) leading to a median ED of 0.20 mSv (IQR 0.14–0.30). On average the acquired images scored 13.3 ± 2.1 (SD) out of a maximum 15 points with an intraclass correlation coefficient (ICC) of 0.94. All acquired series were able to fully answer all clinical questions scoring maximum points (ICC 1.0). Dual source high pitch CT protocols combined with custom contrast agent injection protocols in pediatric patients with CHD delivered sufficiently high diagnostic imaging quality combined with low submilisievert radiation doses. Prospective high pitch imaging is a reliable method for depiction of cardiac anatomy even in very young pediatric CHD patients with elevated heart rates.

Development and application of an electronic synoptic report for reporting and management of low-dose computed tomography lung cancer screening examination

BackgroundInterpretation of Low Dose CT scans and protocol driven management of findings is a key aspect of lung cancer screening program performance. Reliable and reproducible methods are needed to communicate radiologists’ interpretation to the screening program or clinicians driving management decision.MethodsWe performed an audit of a subset of dictated reports from the PANCAN study to assess for omissions. We developed an electronic synoptic reporting tool for radiologists embedded in a clinical documentation system software. The tool was then used for reporting as part of the Alberta Lung Cancer Screening Study and McGill University Health Centre Pilot Lung Cancer Screening Program.ResultsFifty reports were audited for completeness. At least one omission was noted in 30 (70%) of reports, with a major omission (missing lobe, size, type of nodule in report or actionable incidental finding in recommendation section of report) in 24 (48%). Details of the reporting template and functionality such as automated nodule cancer risk assessment, Lung-RADS category assignment, auto-generated narrative type report as well as personalize participant results letter is provided. A description of the system’s performance in its application in 2815 CT reports is then summarized.ConclusionsWe found that narrative type radiologist reports for lung cancer screening CT examinations frequently lacked specific discrete data elements required for management. We demonstrate the successful implementation of a radiology synoptic reporting system for use in lung cancer screening, and the use of this information to drive program management and communications.

Natural Language Processing for Imaging Protocol Assignment: Machine Learning for Multiclass Classification of Abdominal CT Protocols Using Indication Text Data

A correct protocol assignment is critical to high-quality imaging examinations, and its automation can be amenable to natural language processing (NLP). Assigning protocols for abdominal imaging CT scans is particularly challenging given the multiple organ specific indications and parameters. We compared conventional machine learning, deep learning, and automated machine learning builder workflows for this multiclass text classification task. A total of 94,501 CT studies performed over 4 years and their assigned protocols were obtained. Text data associated with each study including the ordering provider generated free text study indication and ICD codes were used for NLP analysis and protocol class prediction. The data was classified into one of 11 abdominal CT protocol classes before and after augmentations used to account for imbalances in the class sample sizes. Four machine learning (ML) algorithms, one deep learning algorithm, and an automated machine learning (AutoML) builder were used for the multilabel classification task: Random Forest (RF), Tree Ensemble (TE), Gradient Boosted Tree (GBT), multi-layer perceptron (MLP), Universal Language Model Fine-tuning (ULMFiT), and Google’s AutoML builder (Alphabet, Inc., Mountain View, CA), respectively. On the unbalanced dataset, the manually coded algorithms all performed similarly with F1 scores of 0.811 for RF, 0.813 for TE, 0.813 for GBT, 0.828 for MLP, and 0.847 for ULMFiT. The AutoML builder performed better with a F1 score of 0.854. On the balanced dataset, the tree ensemble machine learning algorithm performed the best with an F1 score of 0.803 and a Cohen’s kappa of 0.612. AutoML methods took a longer time for completion of NLP model training and evaluation, 4 h and 45 min compared to an average of 51 min for manual methods. Machine learning and natural language processing can be used for the complex multiclass classification task of abdominal imaging CT scan protocol assignment.

Growth Kinetics and Progression Rate of Bosniak Classification Version 2019 Class III and IV Cystic Renal Masses on Imaging Surveillance.

BACKGROUND. Active surveillance is increasingly used as first-line management for localized renal masses. Triggers for intervention primarily reflect growth kinetics, which have been poorly investigated for cystic masses defined by the Bosniak classification version 2019 (v2019). OBJECTIVE. The purpose of this study was to determine growth kinetics and incidence rates of progression of class III and IV cystic renal masses, as defined by the Bosniak classification v2019. METHODS. This retrospective study included 105 patients (68 men, 37 women; median age, 67 years) with 112 Bosniak v2019 class III or IV cystic renal masses on baseline renal mass protocol CT or MRI examinations performed from January 2005 to September 2021. Mass dimensions were measured. Progression was defined as any of the following: linear growth rate (LGR) of 5 mm/y or greater (representing the clinical guideline threshold for intervention), volume doubling time less than 1 year, T category increase, or N1 or M1 disease. Class III and IV masses were compared. Time to progression was estimated using Kaplan-Meier curve analysis. RESULTS. At baseline, 58 masses were class III and 54 were class IV. Median follow-up was 403 days. Median LGR for class III masses was 0.0 mm/y (interquartile range [IQR], -1.3 to 1.8 mm/y) and for class IV masses was 2.3 mm/y (IQR, 0.0-5.7 mm/y) (p < .001). LGR was at least 5 mm/y in four (7%) class III masses and 15 (28%) class IV masses (p = .005). Two patients, both with class IV masses, developed distant metastases. Incidence rate of progression for class III masses was 11.0 (95% CI, 4.5-22.8) and for class IV masses 73.6 (95% CI, 47.8-108.7) per 100,000 person-days of follow-up. Median time to progression was undefined for class III masses given the small number of progression events and 710 days for class IV masses. Hazard ratio of progression for class IV relative to class III masses was 5.1 (95% CI, 2.5-10.8; p < .001). CONCLUSION. During active surveillance of cystic masses evaluated using the Bosniak classification v2019, class IV masses grew faster and were more likely to progress than class III masses. CLINICAL IMPACT. In comparison with current active surveillance guidelines that treat class III and IV masses similarly, future iterations may incorporate relatively more intensive surveillance for class IV masses.

Analysis of a monocentric computed tomography dosimetric database using a radiation dose index monitoring software: dose levels and alerts before and after the implementation of the adaptive statistical iterative reconstruction on CT images.

To analyze dosimetric data of a single center by a radiation dose index monitoring software evaluating quantitatively the dose reduction obtained with the implementation of the adaptive statistical iterative reconstruction (ASIR) on Computed Tomography in terms of both the value of the dose length product (DLP) and the alerts provided by the dose tool. Dosimetric quantities were acquired using Qaelum DOSE tool (QAELUM NV, Leuven-Heverlee, Belgium). Dose data pertaining to CT examinations were performed using a General Electric Healthcare CT tomography with 64 detectors. CT dose data were collected over 4years (January 1, 2017 to December 31, 2020) and included CT dose length product (DLP). Moreover, all CT examinations that triggered a high radiation dose (twice the median for that study description), termed alerts on Dose tool, were retrieved for the analysis. Two radiologists retrospectively assessed CT examinations in consensus for the images quality and for the causes of the alerts issued. A Chi-square test was used to assess whether there were any statistically significant differences among categorical variable while a Kruskal Wallis test was considered to assess differences statistically significant for continuous variables. Differences statistically significant were found for the DLP median values between the dosimetric data recorded on 2017-2018 versus 2019-2020. The differences were linked to the implementation of ASIR technique at the end of 2018 on the CT scanner. The highest percentage of alerts was reported in the CT study group "COMPLETE ABDOMEN + CHEST + HEAD" (range from 1.26% to 2.14%). A reduction year for year was relieved linked to the CT protocol optimization with a difference statistically significant. The highest percentage of alerts was linked to wrong study label/wrong study protocol selection with a range from 29 to 40%. Automated methods of radiation dose data collection allowed for detailed radiation dose analysis according to protocol and equipment over time. The use of CT ASIR technique could determine considerable reduction in radiation dose.

Preliminary Study on the Combination Effect of Clindamycin and Low Dose Trimethoprim-Sulfamethoxazole on Severe Pneumocystis Pneumonia After Renal Transplantation.

ObjectiveEvaluate the effect of the combination of clindamycin with low-dose trimethoprim-sulfamethoxazole (TMP/SMX) regimen on sever Pneumocystis pneumonia (PCP) after renal transplantation.Method20 severe PCP patients after renal transplantation were included in this historical-control, retrospective study. A 10 patients were treated with the standard dose of TMP/SMX (T group), the other 10 patients were treated with the combination of clindamycin and low dose TMP/SMX (CT group).ResultsAlthough there was no significant difference in the hospital survival between the two groups, the CT protocol improved the PaO2/FiO2 ratio more significantly and rapidly after the 6th ICU day (1.51 vs. 0.38, P = 0.014). CT protocol also ameliorated the pulmonary infiltration and the lactate dehydrogenase level more effectively. Moreover, the CT protocol reduced the incidence of pneumomediastinum (0 vs. 50%, P = 0.008), the length of hospital staying (26.5 vs. 39.0 days, P = 0.011) and ICU staying (12.5 vs. 22.5 days, P = 0.008). Furthermore, more thrombocytopenia (9/10 vs. 3/10, P = 0.020) was emerged in the T group than in the CT group. The total adverse reaction rate was much lower in the CT group than in the T group (8/80 vs. 27/80, P < 0.001). Consequently, the dosage of TMP/SMX was reduced in 8 patients, while only 2 patients in the CT group received TMP/SMX decrement (P = 0.023).ConclusionThe current study proposed that clindamycin combined with low-dose TMP/SMX was more effective and safer the than single use of TMP/SMX for severe PCP patients after renal transplantation (NCT 04328688).

CT-Urography study protocol: Split-Bolus technique

CTU represents the natural technical and instrumental evolution of urography. The multidetector technology, withthe possibility of retro-reconstruction of the images, has allowed the direct representation of the excretory tract witha significant reduction in acquisition times, decreasing motion artifacts and increasing the definition of the processedimages. Split-Bolus CT dynamic study allows us to obtain, in a single image acquisition, both the nephrographic andthe renal excretory phases; at the same time, we can obtain information of the parenchymal organs in the abdominalcavity as in the portal/nephrographic phase of a standard CT protocol. The main advantage of Split-Bolus CTUis undoubtedly the significant saving of the radiation dose administered to the patient, related to the reduction inthe number of phases acquired, with a reported diagnostic efficacy comparable to traditional protocols in terms ofimaging quality. The Split Bolus technique has been used in several clinical contexts, such as in the characterizationof focal liver lesions, in acute pulmonary embolism and in polytrauma patients.

CT-Urography study protocol: Split-Bolus technique

CTU represents the natural technical and instrumental evolution of urography. The multidetector technology, with the possibility of retro-reconstruction of the images, has allowed the direct representation of the excretory tract with a significant reduction in acquisition times, decreasing motion artifacts and increasing the definition of the processed images. Split-Bolus CT dynamic study allows us to obtain, in a single image acquisition, both the nephrographic and the renal excretory phases; at the same time, we can obtain information of the parenchymal organs in the abdominal cavity as in the portal/nephrographic phase of a standard CT protocol. The main advantage of Split-Bolus CTU is undoubtedly the significant saving of the radiation dose administered to the patient, related to the reduction in the number of phases acquired, with a reported diagnostic efficacy comparable to traditional protocols in terms of imaging quality. The Split Bolus technique has been used in several clinical contexts, such as in the characterization of focal liver lesions, in acute pulmonary embolism and in polytrauma patients.

PO-1605 Low dose cone beam CT protocols for image-guided breast and pediatric treatments

PO-1605 Low dose cone beam CT protocols for image-guided breast and pediatric treatments

Performance of LI-RADS Version 2018 on CT for Determining Eligibility for Liver Transplant According to Milan Criteria in Patients at High Risk for Hepatocellular Carcinoma.

BACKGROUND. LI-RADS has been investigated primarily in terms of detection of hepatocellular carcinoma (HCC), with less attention given to its performance, particularly on CT, in determining eligibility for liver transplant (LT). OBJECTIVE. The purpose of our study was to assess the performance of LI-RADS version 2018 (v2018) on CT for the diagnosis of HCC and determination of LT eligibility according to the Milan criteria (MC). METHODS. This retrospective study included 136 patients (110 men, 26 women; mean age, 53.9 ± 8.1 [SD] years) at high-risk for HCC who underwent liver protocol CT within 3 months before LT between January 2010 and December 2018. Two radiologists independently reviewed CT examinations using LI-RADS v2018; Organ Procurement and Transplantation Network (OPTN) classes were constructed from the LI-RADS interpretations. Histopathologic analysis of liver explants served as the reference standard for determining the presence of HCC and LT eligibility based on MC. Diagnostic performance was evaluated. Overall survival (OS) was assessed based on medical record review. RESULTS. Based on histopathologic evaluation of liver explants in the 136 patients, 27 patients had no malignancy, 77 were eligible for LT due to HCC within MC, and 32 were unsuitable for LT (i.e., HCC beyond MC in 16 patients, HCC with macrovascular invasion in 12, non-HCC malignancy in four). LR-5 exhibited per-lesion sensitivity and PPV for HCC of 55.9% and 92.8%, respectively, for reader 1 and 39.8% and 86.5% for reader 2. When considering LR-5 observations to represent HCC in assessing MC, LI-RADS had accuracy for determining LT eligibility of 92.7% for reader 1 and 85.3% for reader 2; OPTN criteria had accuracy for determining LT eligibility of 89.0% for reader 1 and 84.4% for reader 2. Five-year OS for patients within MC versus 5-year OS for patients unsuitable for LT was 92.2 months versus 56.0 months for LI-RADS, 92.6 months versus 47.6 months for OPTN criteria, and 93.3 months versus 55.1 months for histopathologic assessment of liver explants. CONCLUSION. LI-RADS v2018, as evaluated on CT in high-risk patients, shows high PPV for HCC detection and high accuracy for determining LT eligibility based on MC. LT eligibility based on preoperative LI-RADS evaluation is associated with post-LT survival. CLINICAL IMPACT. These findings support the use of LI-RADS on CT in assessing eligibility in patients who are candidates for LT.

IAEA support to the radiation protection of patients in the time of the COVID-19 global pandemic.

The IAEA contribution to the radiation protection of patients during the global COVID-19 pandemic included a webinar on the use of CT and optimization for COVID-19 pneumonia, a survey with 137 responses from 84 sites across five continents, and a study on the CT utilization, protocols and patient doses with data from 62 healthcare sites from 34 countries. This paper outlines the main results of these efforts, which have been presented in the scientific literature and in several national trainings and international meetings.

Panorama of multidetector-row computed tomography findings of carcinoma gall bladder - A retrospective observational study.

Carcinoma of the gall bladder (Ca GB) has marked ethnic and geographical variations with a broad spectrum of imaging findings on multidetector-row computed tomography (MDCT). We aim to study the spectrum of the imaging findings of Ca GB on MDCT in an Eastern Indian hospital as these imaging findings help in accurate diagnosis and staging of this lethal disease. The MDCT images of 100 biopsy-proven cases of adenocarcinoma of GB performed from January 1, 2017, to December 31, 2018, in our hospital were retrospectively reviewed by two experienced radiologists blinded to the diagnosis. The CT protocol was a plain scan followed by triple-phase contrast-enhanced CT. Reconstructed images in the form of maximum intensity projection, volume-rendered technology, and minimum intensity projection images were also assessed. Descriptive statistics were used for data analysis. Ca GB showed a female predominance (female:male -1.9:1). The mean age of presentation was 54.7 years (females) and 58 years (males). The morphological patterns were a mass replacing the GB (46%), focal or diffuse wall thickening (26%), and an intraluminal polypoidal mass (28%). Direct extension was to liver (76%), duodenum (32%), colon (19%), pancreas (9%), and abdominal wall (1%). Biliary dilatation (53%), vascular invasion (14%), omental involvement (23%), ascites (22%), N1 (40%), and retroperitoneal lymphadenopathy (33%) were common. Distant metastasis comprised of hepatic (42%), pulmonary (7%), Krukenberg's tumor (6%), and osseous (1%) lesions. The stages at diagnosis were I or II (3%), IIIA (4%), IIIB (16%), IVA (10%), and IVB (67%). Ca GB has a broad spectrum of findings on MDCT and it mostly presents at an advanced stage. MDCT with reconstructions is beneficial in the assessment of locoregional and distant spread and cancer staging which has a direct implication on patient management, survival, and mortality.

Strategies for Dose Optimization: Views From Health Care Systems.

Advances in CT have facilitated widespread use of medical imaging while increasing patient lifetime exposure to ionizing radiation. To describe dose optimization strategies used by health care organizations to optimize radiation dose and image quality. A qualitative study of semistructured interviews conducted with 26 leaders from 19 health care systems in the United States, Europe, and Japan. Interviews focused on strategies that were used to optimize radiation dose at the organizational level. A directed content analysis approach was used in data analysis. Analysis identified seven organizational strategies used by these leaders for optimizing CT dose: (1) engaging radiologistsand technologists, (2) establishing a CT dose committee, (3) managing organizational change, (4) providing leadershipand support, (5) monitoring and benchmarking, (6) modifying CT protocols, and (7) changes in equipment and work rules. Leaders in these health systems engaged in specific strategies to optimize CT dose within their organizations. The strategies address challenges health systems encounter in optimizing CT dose at the organizational level and offer an evolving framework for consideration in dose optimization efforts for enhancing safety and use of medical imaging.

Effectiveness of Tube Voltage Selection of 70 kV in Abdominal Dual Energy CT Protocol

Recently, CT equipment has a dose modulation function that adjusts the dose to the patient. But, the dose is proportional to the tube voltage and changes with the square of the tube current. Therefore, reducing tube voltage rather than tube current has a greater effect on reducing radiation exposure. High tube voltage is used to improve image noise and contrast resolution. When high tube voltage is used, the surface dose is reduced, but the overall exposure dose is increased. So, the dose should be appropriately adjusted to the patient. Accordingly, research and attempts to obtain high-quality images with a small dose are continuously being conducted, the development of detectors and software performance are improving. Due to the improvement of CT equipment, 70 kV can be used for dual scan. In this study, the 70 kV, and 80 kV, 90 kV, 100 kV used in the conventional CT examination were compared and evaluated at the same dose. The study was conducted using ACR Phantom and KAGAKU Abdomen Phantom. CT number(HU), Noise, SNR, and CNR of each image were compared by quantitative evaluation, and CT number and noise level were evaluated by qualitative evaluation. As a result of comparison, using 70 kV obtained equivalent or better noise, CT number, SNR, and CNR than 80 kV, 90 kV, and 100 kV with the same CTDIvol. In conclusion, it is considered that diagnostically excellent image can be obtained with a small exposure dose by dual scan using 70 kV.

The effect of variations in CT scan protocol on femoral finite element failure load assessment using phantomless calibration.

Recently, it was shown that fracture risk assessment in patients with femoral bone metastases using Finite Element (FE) modeling can be performed using a calibration phantom or air-fat-muscle calibration and that non-patient-specific calibration was less favorable. The purpose of this study was to investigate if phantomless calibration can be used instead of phantom calibration when different CT protocols are used. Differences in effect of CT protocols on Hounsfield units (HU), calculated bone mineral density (BMD) and FE failure loads between phantom and two methods of phantomless calibrations were studied. Five human cadaver lower limbs were scanned atop a calibration phantom according to a standard scanning protocol and seven additional commonly deviating protocols including current, peak kilovoltage (kVp), slice thickness, rotation time, field of view, reconstruction kernel, and reconstruction algorithm. The HUs of the scans were calibrated to BMD (in mg/cm3) using the calibration phantom as well as using air-fat-muscle and non-patient-specific calibration, resulting in three models for each scan. FE models were created, and failure loads were calculated by simulating an axial load on the femur. HU, calculated BMD and failure load of all protocols were compared between the three calibration methods. The different protocols showed little variation in HU, BMD and failure load. However, compared to phantom calibration, changing the kVp resulted in a relatively large decrease of approximately 10% in mean HU and BMD of the trabecular and cortical region of interest (ROI), resulting in a 13.8% and 13.4% lower failure load when air-fat-muscle and non-patient-specific calibrations were used, respectively. In conclusion, while we observed significant correlations between air-fat-muscle calibration and phantom calibration as well as between non-patient-specific calibration and phantom calibration, our sample size was too small to prove that either of these calibration approaches was superior. Further studies are necessary to test whether air-fat-muscle or non-patient-specific calibration could replace phantom calibration in case of different scanning protocols.

Giant Cell Arteritis: Updates and Controversies.

Giant cell arteritis (GCA) is a systemic granulomatous vasculitis affecting the medium and large-size arteries, and may present with a range of ophthalmic findings. This review will cover GCA epidemiology, pathophysiology, clinical presentation, diagnostic workup, and treatment. GCA is commonly found in elderly patients and individuals of Scandinavian descent. Recent publications suggest it may be more common in African Americans and Hispanics than previously thought. It is very rare in Asian and Middle-Eastern populations, and there is little data regarding African populations. Genetic studies have identified increased risk associated with HLA-DRB1*04. Rather than a response to a specific antigen such as varicella zoster virus, current immunology research suggests that GCA results from changes associated with the aging immune system. Arteritic anterior ischemic optic neuropathy is the most common ophthalmic manifestation of GCA, but central or branch retinal artery occlusion, ophthalmic artery occlusion, cranial neuropathies causing diplopia, and more rarely anterior segment ischemia and anisocoria may also occur. Clinical testing including visual field testing, OCT, OCT-A, ICG and fluorescein angiography can be helpful in suggesting a diagnosis in addition to the clinical exam. GCA is ultimately a clinical diagnosis, but it is usually supported with lab results, pathology, and/or imaging. Temporal artery biopsy (TAB) remains the gold standard diagnostic test although its sensitivity is debated and practice patterns still vary with respect to sample length and whether unilateral or simultaneous bilateral biopsies are performed. Some studies have reported higher sensitivity of ultrasounds over TAB, with added benefits of time efficiency and cost effectiveness, promoting the diagnostic use of ultrasounds. MRI and even PET CT protocols offer additional options for less invasive diagnostic testing. Vision-threatening GCA is treated acutely with emergent admission for intravenous methylprednisolone, and long-term high dose oral corticosteroids remain the standard of care, despite common and sometimes serious side effects. The use of steroid-sparing alternatives such as tocilizumab is becoming more common and additional agents are being investigated.

Automatic vs manual coronary CT angiography reconstruction for whole-heart coverage CT scanner: a comparison study in general patient population.

Due to the limited temporal resolution and cardiac motion, coronary computed tomography angiography (CCTA) exam is one of the most challenging CT protocols which may require operating radiologist to apply additional phase adjustment or motion correction for image reconstruction. To evaluate image quality between automatic and manual CCTA reconstruction in a 0.25 second rotation time, 16 cm coverage, single-beat, CT scanner with automated phase selection and AI-assisted motion correction. CCTA exams of 535 consecutive patients were included. All exams were first reconstructed with an automatically selected phase. If there was an unacceptable motion artifact, a manual reconstruction process was performed by radiologists. Additionally, automatic image series which consist of auto-phase selection and a follow-up motion correction were reconstructed. For these two manual and automatic image series, a four-point Likert scale rating system was used to evaluate image quality of the coronary artery segment by two experienced radiologists, according to the 18-segment model. Fifty-one patients (9.5%) did not have satisfactory image quality after auto-phase selection. In these patients, the heart rate during scanning was higher (78.3±18.4 bpm) than in the remaining 484 patients (68.9±13.1 bpm). Overall, 734 out of the 918 vessel segments were identified for quality evaluation among 51 patients. Automatic and manual image series were rated as having average Likert scores of 3.48±0.62 and 3.32±0.67 (P < 0.001), respectively. Using a 0.25 second rotation speed, 16 cm z-coverage, CT scanner installed with an AI-assisted motion correction algorithm, the automatic image reconstruction with scanner equipped auto-phase-selection and motion correction algorithm outperforms manually controlled image reconstruction by radiologists. This suggests that the traditional CCTA exam reconstruction workflow could be altered allowing less radiologist involvement and becoming more efficient.

National reference levels of CT procedures dedicated for treatment planning in radiation oncology

ObjectiveTo present results of the first national survey on reference levels of CT imaging performed for the treatment planning purposes in radiation oncology in Croatia. MethodsData for CT protocols of five anatomical regions including head, head and neck, pelvis, breast, and thorax were collected at eight radiation oncology departments in Croatia. Data included volume CT dose index (CTDIvol), dose-length product (DLP), scan length and set of acquisition and reconstruction parameters. Data on a total of 600 patients were collected. Median values of scan length, DLP and CTDIvol were calculated for each acquisition protocol. Third quartiles of the median CTDIvol and DLP values were proposed as the national radiotherapy planning reference levels (RPRL). ResultsThe largest CoV were assessed for RT Breast (63.8% for CTDIvol), RT Thorax (79.7% for DLP) and RT H&N (21.2% for scan length). RT Head had the lowest CoV for CTDIvol (1,9%) and DLP (17,2%), while RT Breast had the lowest coefficient of variation for scan length (12.8%). Proposed national RPRLs are: for RT Head CTDIvol16cm = 62 mGy and DLP16cm = 1738 mGy.cm; for RT H&N CTDIvol16cm = 35 mGy and DLP16cm = 1444 mGy.cm; for RT Breast CTDIvol32cm = 16 mGy and DLP32cm = 731 mGy.cm; for RT Thorax CTDIvol32cm = 17 mGy and DLP32cm = 865 mGy.cm; for RT Pelvis CTDIvol32cm = 20 mGy and DLP32cm = 1133 mGy.cm. ConclusionsResults of this study show variations in CT imaging for treatment planning practice at the national level which call for optimization of procedures.

Imaging Insights Into Abdominal Wall Function.

PurposeThe successful repair of any complex ventral hernia requires a thorough understanding of the underlying anatomical defect and its functional context. We describe an improved “functional” approach to CT imaging of the abdominal wall that can facilitate this understanding and assist surgical planning.MethodsThis invited article reports the observational experience gained from the functional abdominal wall CT examinations of 88 patients who underwent complex ventral hernia repair using pre-operative Botulinum toxin A (BTA) infiltration of the lateral oblique abdominal muscles as well as a further eight patients with diastasis rectus abdominis who were examined to exclude ventral hernia.ResultsThe use of a functional CT protocol which supplements resting images with additional “crunching” images (acquired with the abdominal wall muscles all strongly contracted) can significantly improve the demonstration of ventral hernia defects. Crunching acquisitions can also help differentiate true hernias from dysfunctional bulges, identify muscle denervation or atrophic changes, reveal otherwise occult hernias that may be missed on resting or Valsalva images alone, and assist the pre-operative assessment of BTA effect.ConclusionA more functional approach to pre-operative CT imaging of the abdominal wall can significantly improve the understanding of complex ventral hernia defects and help formulate effective surgical plans that achieve low recurrence rates and good functional outcomes.