The Efficiency of Radiation Shielding Sheet to Reduce Radiation Exposure during C-arm Fluoroscopy

Purpose@#This study evaluates the radiation shielding performance of a new lead-free tungsten-based sheet to reduce the radiation exposure of operators and patients under C-arm fluoroscopy. @*Materials and Methods@#A non-lead radiation shielding sheet (ROO201128; Pentas, Korea) was fabri-cated using tungsten and bismuth. The dose measurements were conducted using a C-arm fluoroscopy machine at 64 kVp and 1.5 mA, assuming two possible scenarios according to the position of the sheet. In each scenario, measurements were conducted at three distances (30, 60, and 90 cm) away from the beam center and in three directions (cephal, caudal, and operator’s direction). @*Results@#In the area within a radius of 60 cm from the beam center, the measured doses were reduced by 66.3% on mean, and the doses measured at distances more than 60 cm were less than 0.1 mSv/h in both scenarios. The most beneficial utilization of the lead-free shielding sheet was verified during C-arm fluoroscopy by placing the sheet on the X-ray tube. The operator’s radiation exposure was reduced by 56.6% when the sheet was placed under the phantom, and by 81.0% when the sheet was placed on the X-ray tube. @*Conclusion@#The use of lead-free radiation shielding sheets under C-arm fluoroscopy was effective in reducing radiation exposure, and the most beneficial scenario in which the sheet can be utilized was verified when the sheet was placed on the X-ray tube.

Clinical Significance and Characteristics of Newly Detected Lesions on Breast MRI During Neoadjuvant Chemotherapy

Purpose@#This study aimed to evaluate clinical significance and imaging findings of newly detected lesions on breast MRI while monitoring patients’ response to neoadjuvant chemotherapy (NAC). @*Materials and Methods@#We identified 291 patients with newly diagnosed breast cancer who underwent breast MRI to assess their response to NAC between January 2017 and August 2021. We evaluated 26 new lesions in 24 women (mean age, 49.8 years; range, 35–63 years) who were included in this study. Two radiologists assessed imaging findings of new lesions according to Breast Imaging Reporting and Data System (BI-RADS) lexicon 5th edition and evaluated follow-up MRI during NAC. Outcomes of new lesions were determined based on pathologic examination or imaging follow-up after surgery. @*Results@#All 26 new lesions were found on the first follow-up imaging. They disappeared or decreased in size on the second follow-up imaging. Lesion types included mass (n = 22, 84.6%) and non-mass enhancement (n = 4, 15.4%). The majority of the mass types showed oval to round shapes (22/22, 100%), circumscribed margins (21/22, 95.5%), and rim enhancement (18/22, 81.8%). Seven (26.9%) new lesions were ipsilateral to the index cancer, 7 (26.9%) were contralateral, and 12 (46.2%) were bilateral. None of these new lesions were malignant. @*Conclusion@#New lesions were detected in 4.7% of breast MRI during NAC. Most new lesions tended to

Beyond Coronary CT Angiography: CT Fractional Flow Reserve and Perfusion

Cardiac CT has been proven to provide diagnostic and prognostic evaluation of coronary artery disease for cardiovascular risk stratification and treatment decision-making based on rapid technological development and various research evidence. Coronary CT angiography has emerged as a gateway test for coronary artery disease that can reduce invasive angiography due to its high negative predictive value, but the diagnostic specificity is relatively low. However, coronary CT angiography is likely to overcome its limitations through functional evaluation to identify the hemodynamic significance of coronary artery disease by analyzing myocardial perfusion and fractional flow reserve through cardiac CT. Recently, studies have been actively conducted to incorporate artificial intelligence to make this more objective and reproducible. In this review, functional imaging techniques of cardiac computerized tomography are explored.

The Potential Role of Cardiac CT in Patients with Acute Coronary Syndrome

Acute coronary syndrome involves three types of coronary artery disease associated with sudden rupture of coronary artery plaque, and has a clinical presentation ranging from ST-segment elevation myocardial infarction (STEMI) to non-ST-segment elevation myocardial infarction (NSTEMI) or unstable angina. Cardiac CT can help quantify and characterize atherosclerotic plaques. According to a previous study, low-attenuation plaque, napkin ring sign, positive remodeling, spotty calcification, and increased perivascular fat attenuation are associated with plaque ruptures on cardiac CT. Therefore, coronary artery stenosis, as well as acute coronary artery syndrome, can be diagnosed using cardiac CT.

Comparison of a Deep Learning-Based Reconstruction Algorithm with Filtered Back Projection and Iterative Reconstruction Algorithms for Pediatric Abdominopelvic CT

Objective@#To compare a deep learning-based reconstruction (DLR) algorithm for pediatric abdominopelvic computed tomography (CT) with filtered back projection (FBP) and iterative reconstruction (IR) algorithms. @*Materials and Methods@#Post-contrast abdominopelvic CT scans obtained from 120 pediatric patients (mean age ± standard deviation, 8.7 ± 5.2 years; 60 males) between May 2020 and October 2020 were evaluated in this retrospective study. Images were reconstructed using FBP, a hybrid IR algorithm (ASiR-V) with blending factors of 50% and 100% (AV50 and AV100, respectively), and a DLR algorithm (TrueFidelity) with three strength levels (low, medium, and high). Noise power spectrum (NPS) and edge rise distance (ERD) were used to evaluate noise characteristics and spatial resolution, respectively. Image noise, edge definition, overall image quality, lesion detectability and conspicuity, and artifacts were qualitatively scored by two pediatric radiologists, and the scores of the two reviewers were averaged. A repeated-measures analysis of variance followed by the Bonferroni post-hoc test was used to compare NPS and ERD among the six reconstruction methods. The Friedman rank sum test followed by the Nemenyi-Wilcoxon-Wilcox all-pairs test was used to compare the results of the qualitative visual analysis among the six reconstruction methods. @*Results@#The NPS noise magnitude of AV100 was significantly lower than that of the DLR, whereas the NPS peak of AV100 was significantly higher than that of the high- and medium-strength DLR (p < 0.001). The NPS average spatial frequencies were higher for DLR than for ASiR-V (p < 0.001). ERD was shorter with DLR than with ASiR-V and FBP (p < 0.001). Qualitative visual analysis revealed better overall image quality with high-strength DLR than with ASiR-V (p < 0.001). @*Conclusion@#For pediatric abdominopelvic CT, the DLR algorithm may provide improved noise characteristics and better spatial resolution than the hybrid IR algorithm.

Frequency of reoperation in patients who underwent breast reconstruction using Allergan implants after an interview about breast implant-associated anaplastic large cell lymphoma

Background@#In recent years, breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) has emerged as an important concern. At our institution, patients who received breast reconstruction using Allergan implants were informed individually about BIA-ALCL. The present study analyzed correlations between patients’ level of satisfaction with their breast shape and whether they chose to undergo reoperation (implant removal or replacement). @*Methods@#Breast reconstruction with Allergan implants was performed between December 2014 and April 2018. In total, 107 patients were interviewed, excluding those who had died, were unreachable, or had already undergone reoperation. The mean follow-up period was 53 months (range, 26–73 months). @*Results@#After the interviews, 68 patients postponed reoperation, 29 had their implant replaced, and 10 had their implant removed. Nearly one-fifth (18.9%) of patients who were satisfied with their breast shape (13 out of 69) underwent reoperation due to anxiety over ALCL. Meanwhile, 68.4% of patients who were not satisfied due to capsular contracture or scar contracture (26 out of 38) underwent reoperation. Sixteen of the 30 patients who received postoperative radiotherapy (53.3%) chose to undergo reoperation. @*Conclusions@#Satisfaction with the cosmetic outcomes of implant placement played a meaningful role in patients’ decisions to undergo reoperation. This tendency may be linked to postoperative radiotherapy, which is a major contributor to complications such as contracture. Nonetheless, a substantial proportion of patients who were satisfied with the outcomes chose to undergo reoperation due to concerns regarding ALCL.

Volumetric change of the latissimus dorsi muscle after postoperative chemotherapy and radiotherapy in immediate breast reconstruction with an extended latissimus dorsi musculocutaneous flap: final results from serial studies

Background@#Breast reconstruction using an extended latissimus dorsi (eLD) flap can supplement more volume than reconstruction using various local flaps after partial mastectomy, and it is a valuable surgical method since the reconstruction area is not limited. However, when performing reconstruction, the surgeon should consider latissimus dorsi (LD) volume reduction due to postoperative chemotherapy (POCTx) and postoperative radiotherapy (PORTx). To evaluate the effect of POCTx and PORTx on LD volume reduction, the effects of each therapy—both separately and jointly—need to be demonstrated. The present study quantified LD volume reduction in patients who underwent POCTx and PORTx after receiving breast-conserving surgery (BCS) with an eLD flap. @*Methods@#This study included 48 patients who received immediate breast reconstruction using an eLD flap from January 2013 to March 2017, had chest computed tomography (CT) 7–10 days after surgery and 10–14 months after radiotherapy completion, and were observed for more than 3 years postoperatively. One surgeon performed the breast reconstruction procedures, and measurements of breast volume were obtained from axial CT views, using a picture archiving and communication system. A P-value <0.05 was the threshold for statistical significance. @*Results@#The average volume reduction of LD at 10–14 months after completing POCTx and PORTx was 64.5% (range, 42.8%–81.4%) in comparison to the volume measured 7–10 days after surgery. This change was statistically significant (P<0.05). @*Conclusions@#Based on the findings of this study, when harvesting an eLD flap, surgeons should anticipate an average LD volume reduction of 64.5% if chemotherapy and radiotherapy are scheduled after BCS with an eLD flap.

Prediction of endotracheal tube size using a printed three-dimensional airway model in pediatric patients with congenital heart disease: a prospective, single-center, single-group study / 대한마취과학회지

Background@#To determine the correct size of endotracheal tubes (ETTs) for endotracheal intubation of pediatric patients, new methods have been investigated. Although the three-dimensional (3D) printing technology has been successful in the field of surgery, there are not many studies in the field of anesthesia. The purpose of this study was to evaluate the accuracy of a 3D airway model for prediction of the correct ETT size, and compare the results with a conventional age-based formula in pediatric patients. @*Methods@#Thirty-five pediatric patients under six years of age who were scheduled for congenital heart surgery were enrolled. In the pre-anesthetic period, the patient’s computed tomography (CT) images were converted to Standard Triangle Language (STL) files using the 3D conversion program. A Fused Deposition Modelling (FDM) type 3D printer was used to print 3D airway models from the sub-glottis to the upper carina. ETT size was selected by inserting various sized cuffed-ETTs to a printed 3D airway model. @*Results@#The 3D method selected the correct ETT size in 21 out of 35 pediatric patients (60%), whereas the age-based formula selected the correct ETT size in 9 patients (26%). @*Conclusions@#Prediction of the correct size of ETTs using a printed 3D airway model demonstrated better results than the age-based formula. This suggests that the selection of ETT size using a printed 3D airway model may be feasible for helping minimize re-intubation attempts and complications in patients with congenital heart disease and/or those with an abnormal range of growth and development.

Prediction of endotracheal tube size using a printed three-dimensional airway model in pediatric patients with congenital heart disease: a prospective, single-center, single-group study / 대한마취과학회지

Background@#To determine the correct size of endotracheal tubes (ETTs) for endotracheal intubation of pediatric patients, new methods have been investigated. Although the three-dimensional (3D) printing technology has been successful in the field of surgery, there are not many studies in the field of anesthesia. The purpose of this study was to evaluate the accuracy of a 3D airway model for prediction of the correct ETT size, and compare the results with a conventional age-based formula in pediatric patients. @*Methods@#Thirty-five pediatric patients under six years of age who were scheduled for congenital heart surgery were enrolled. In the pre-anesthetic period, the patient’s computed tomography (CT) images were converted to Standard Triangle Language (STL) files using the 3D conversion program. A Fused Deposition Modelling (FDM) type 3D printer was used to print 3D airway models from the sub-glottis to the upper carina. ETT size was selected by inserting various sized cuffed-ETTs to a printed 3D airway model. @*Results@#The 3D method selected the correct ETT size in 21 out of 35 pediatric patients (60%), whereas the age-based formula selected the correct ETT size in 9 patients (26%). @*Conclusions@#Prediction of the correct size of ETTs using a printed 3D airway model demonstrated better results than the age-based formula. This suggests that the selection of ETT size using a printed 3D airway model may be feasible for helping minimize re-intubation attempts and complications in patients with congenital heart disease and/or those with an abnormal range of growth and development.

Clinical and Imaging Findings of Neonatal Seizures Presenting as Diffuse Cerebral White Matter Abnormality on Diffusion-Weighted Imaging without any Structural or Metabolic Etiology

Purpose@#Some patients with neonatal seizures show diffuse, symmetric diffusion-restricted lesions in the cerebral white matter. The aim of this study was to describe clinical and imaging findings of patients with neonatal seizures who had diffuse, symmetric diffusion-restricted lesions without any structural or metabolic etiology. @*Materials and Methods@#A total of 56 neonates aged less than 1 week underwent brain magnetic resonance imaging (MRI) for evaluation of seizures from November 2008 to February 2017. After excluding 43 patients, 13 patients showed diffuse white matter abnormality on diffusion-weighted imaging. Initial and follow-up clinical and MRI findings were analyzed retro-spectively. @*Results@#All 13 patients were born at full term. Among the ten patients who underwent a stool test for viruses, six were positive for rotavirus and one for astrovirus. MRI revealed diffuse, symmetric diffusion-restricted lesions distributed along the cerebral white matter, thalami, and midbrain variably. @*Conclusion@#Diffuse, symmetric diffusion-restricted lesions involving the cerebral white matter can be seen in patients with neonatal seizures without any structural or metabolic etiology. Rotavirus is commonly but not exclusively detected in these patients. Nevertheless, viral infection-associated encephalopathy should be considered for patients with characteristic clinical and MRI findings.

Comparison of breast volume change between oncoplastic breast-conserving surgery with radiation therapy and a simultaneous contralateral balancing procedure through the inverted-T scar technique

Background@#Reduction mammoplasty or mastopexy is performed as an additional balancing procedure in patients with large or ptotic breasts who undergo breast-conserving surgery (BCS). Radiation therapy on breasts that have undergone surgery may result in changes in the volume. This study presents a comparative analysis of patients who received post-BCS balancing procedures to determine whether volume changes were larger in breasts that received radiation therapy than on the contralateral side. @*Methods@#Thirty-six participants were selected among patients who received BCS using the inverted-T scar technique between September 2012 and July 2017, were followed up for 2 or more years, and had pre-radiation therapy computed tomography images and post-radiation therapy images taken between 12 and 18 months after completion. The average age of the participants was 53.5 years, their average body mass index was 26.62 kg/m2. @*Results@#The pre- and post-radiation therapy volumes of the breasts receiving BCS were 666.08±147.48 mL and 649.33±130.35 mL, respectively. In the contralateral breasts, the volume before radiation therapy was 637.69±145.72 mL, which decreased to 628.14±166.41 mL after therapy. The volume ratio of the affected to the contralateral breasts was 1.05±0.10 before radiation therapy and 1.06±0.12 after radiation therapy. @*Conclusions@#The ratio of the volume between the two breasts immediately after surgery and at roughly 18 months postoperatively was not significantly different (P=0.98). For these reasons, we recommend a simultaneous single-stage balancing procedure as a reasonable option for patients who require radiation therapy after BCS without concerns regarding volume change.

Volumetric change of the latissimus dorsi muscle after postoperative radiotherapy in immediate breast reconstruction with an extended latissimus dorsi musculocutaneous flap

Background@#This study aimed to determine the magnitude of volume reduction of the latissimus dorsi (LD) muscle after treatment using only postoperative radiotherapy (PORTx) in patients who underwent immediate breast reconstruction using an extended LD musculocutaneous (eLDMC) flap after partial mastectomy. @*Methods@#We retrospectively reviewed 28 patients who underwent partial mastectomy and an eLDMC flap, received only PORTx, and underwent chest computed tomography (CT) 7 to 10 days after surgery and 18±4 months after the end of radiotherapy, from March 2011 to June 2016. The motor nerve to the LD was resected in all patients. One plastic surgeon performed the procedures, and the follow-up period was at least 36 months (mean, 46.6 months). The author obtained LD measurements from axial CT views, and the measurements were verified by an experienced radiologist. The threshold for statistical significance was set at P<0.05. @*Results@#A statistically significant decrease in the LD volume was found after the end of PORTx (range, 61.19%–80.82%; mean, 69.04%) in comparison to the measurements obtained 7 to 10 days postoperatively (P<0.05). All cases were observed clinically for over 3 years. @*Conclusions@#The size of an eLDMC flap should be determined considering an average LD reduction of 69% after PORTx. Particular care should be taken in determining the size of an eLDMC flap if the LD is thick or if it occupies a large portion of the flap.

Application of Three-Dimensional Printed Models in Congenital Heart Surgery: Surgeon's Perspective

To treat congenital heart disease, it is important to understand the anatomical structure correctly. Three-dimensional (3D) printed models of the heart effectively demonstrate the structural features of congenital heart disease. Occasionally, the exact characteristics of complex cardiac malformations are difficult to identify on conventional computed tomography, magnetic resonance imaging, and echocardiography, and the use of 3D printed models can help overcome their limitations. Recently, 3D printed models have been used for congenital heart disease education, preoperative simulation, and decision-making processes. In addition, we will pave the way for the development of this technology in the future and discuss various aspects of its use, such as the development of surgical techniques and training of cardiac surgeons.

Application of Three-Dimensional Printed Models in Congenital Heart Surgery: Surgeon's Perspective

To treat congenital heart disease, it is important to understand the anatomical structure correctly. Three-dimensional (3D) printed models of the heart effectively demonstrate the structural features of congenital heart disease. Occasionally, the exact characteristics of complex cardiac malformations are difficult to identify on conventional computed tomography, magnetic resonance imaging, and echocardiography, and the use of 3D printed models can help overcome their limitations. Recently, 3D printed models have been used for congenital heart disease education, preoperative simulation, and decision-making processes. In addition, we will pave the way for the development of this technology in the future and discuss various aspects of its use, such as the development of surgical techniques and training of cardiac surgeons.

Volumetric change of the latissimus dorsi muscle after immediate breast reconstruction with an extended latissimus dorsi musculocutaneous flap

BACKGROUND: In immediate breast reconstruction using an extended latissimus dorsi musculocutaneous (eLDMC) flap, the volume of the flap decreases, which causes a secondary deformity of the breast shape. Since little research has investigated this decrease in muscle volume, the authors conducted an objective study to characterize the decrease in muscle volume after breast reconstruction using an eLDMC flap. METHODS: Research was conducted from October 2011 to November 2016. The subjects included 23 patients who underwent mastectomy due to breast cancer, received immediate reconstruction using an eLDMC flap without any adjuvant chemotherapy or radiotherapy, and received a computed tomography (CT) scan from days 7 to 10 after surgery and 6 to 8 months postoperatively. In 10 patients, an additional CT scan was conducted 18 months postoperatively. Axial CT scans were utilized to measure the volumetric change of the latissimus dorsi muscle during the follow-up period. RESULTS: In the 23 patients, an average decrease of 54.5% was observed in the latissimus dorsi muscle volume between the images obtained immediately postoperatively and the scans obtained 6 to 8 months after surgery. Ten patients showed an average additional decrease of 11.9% from 6–8 months to 18 months after surgery. CONCLUSIONS: We studied changes in the volume of the latissimus dorsi muscle after surgery using an eLDMC flap performed after a mastectomy without adjuvant chemotherapy or radiotherapy. In this study, we found that immediate breast reconstruction using a latissimus dorsi muscle flap led to a decrease in muscle volume of up to 50%.

User-Friendly Vendor-Specific Guideline for Pediatric Cardiothoracic Computed Tomography Provided by the Asian Society of Cardiovascular Imaging Congenital Heart Disease Study Group: Part 1. Imaging Techniques

Optimal performance of pediatric cardiothoracic computed tomography (CT) is technically challenging and may need different approaches for different types of CT scanners. To meet the technical demands and improve clinical standards, a practical, user-friendly, and vendor-specific guideline for pediatric cardiothoracic CT needs to be developed for children with congenital heart disease (CHD). In this article, we have attempted to describe such guideline based on the consensus of experts in the Asian Society of Cardiovascular Imaging CHD Study Group. This first part describes the imaging techniques of pediatric cardiothoracic CT, and it includes recommendations for patient preparation, scan techniques, radiation dose, intravenous injection protocol, post-processing, and vendor-specific protocols.

Image Quality and Radiation Dose in CT Venography Using Model-Based Iterative Reconstruction at 80 kVp versus Adaptive Statistical Iterative Reconstruction-V at 70 kVp

OBJECTIVE: To compare the objective and subjective image quality indicators and radiation doses of computed tomography (CT) venography performed using model-based iterative reconstruction (MBIR) at 80 kVp and adaptive statistical iterative reconstruction (ASIR)-V at 70 kVp. MATERIALS AND METHODS: Eighty-three patients who had undergone CT venography of the lower extremities with MBIR at 80 kVp (Group A; 21 men and 20 women; mean age, 55.5 years) or ASIR-V at 70 kVp (Group B; 18 men and 24 women; mean age, 57.3 years) were enrolled. Two radiologists retrospectively evaluated the objective (vascular enhancement, image noise, signal-to-noise ratio [SNR], contrast-to-noise ratio [CNR]) and subjective (quantum mottle, delineation of contour, venous enhancement) image quality indicators at the inferior vena cava and femoral and popliteal veins. Clinical information, radiation dose, reconstruction time, and objective and subjective image quality indicators were compared between groups A and B. RESULTS: Vascular enhancement, SNR, and CNR were significantly greater in Group B than in Group A (p ≤ 0.015). Image noise was significantly lower in Group B (p ≤ 0.021), and all subjective image quality indicators, except for delineation of vein contours, were significantly better in Group B (p ≤ 0.021). Mean reconstruction time was significantly shorter in Group B than in Group A (1 min 43 s vs. 131 min 1 s; p < 0.001). Clinical information and radiation dose were not significantly different between the two groups. CONCLUSION: CT venography using ASIR-V at 70 kVp was better than MBIR at 80 kVp in terms of image quality and reconstruction time at similar radiation doses.

Contralateral Internal Mammary Lymphadenopathy Mimicking Metastasis in a Patient with a History of Breast Cancer and Prior Interstitial Mammoplasty by Paraffin Injection: MRI, PET-CT, and Pathological Findings

Foreign body injections into breasts may produce foreign body reactions, fibrosis, and local swelling of involved lymph nodes, which can be misdiagnosed as metastasis or malignancy. Here, the authors report MR imaging, PET-CT imaging, and pathologic findings of contralateral internal mammary lymphadenopathy suspicious of breast cancer metastasis in a 58-year-old woman with history of left breast cancer, and previous interstitial mammoplasty by paraffin injection in both breasts.

Comparison of Image Qualities of 80 kVp and 120 kVp CT Venography Using Model-Based Iterative Reconstruction at Same Radiation Dose

PURPOSE@#To compare image qualities of 80 kVp CT venography (CTV) and 120 kVp CTV by model-based iterative reconstruction (MBIR) at the same radiation dose.@*MATERIALS AND METHODS@#Sixty-nine patients that underwent CTV using 80 kVp (36 patients, group 1) or 120 kVp (33 patients, group 2) with MBIR at the same radiation dose were enrolled, and objective and subjective image qualities were assessed independently by two radiologists.@*RESULTS@#Mean vascular enhancement and contrast-to-noise ratio were significantly higher in group 1 than in group 2 for inferior vena cavas, femoral veins, and popliteal veins (p < 0.001), and there was significantly lower objective image noise in group 1 (p < 0.001). Subjective analysis revealed image quality was significantly higher in group 1 and image noise was significantly higher in group 2 (p < 0.001). Mean dose-length products was not significantly lower in group 1 (356.1 ± 153.7 mGy cm) than in group 2 (370.1 ± 77.1 mGy cm) (p = 0.635).@*CONCLUSION@#CTV at 80 kVp with MBIR is a better protocol than CTV at 120 kVp with MBIR at the same radiation dose.

Percutaneous transhepatic hepatic venous stenting after extracorporeal hepatic resection and autotransplantation: A case report

We report a case of percutaneous transhepatic stent placement for the treatment of hepatic venous outflow obstruction after extracorporeal hepatic resection and autotransplantation. A 63-year-old woman with a large mass in the liver was asymptomatic with no hepatic virus infection. Because the tumor was unresectable by conventional means, we used extracorporeal hepatic resection and autotransplantation for operation. Two days after surgery, hepatic venous outflow obstruction of the right and right inferior hepatic veins was suspected on computed tomography. After failure of the transjugular approach, hepatic venous stenting was performed successfully via the percutaneoustranshepatic approach.