Optimization of null point in Look-Locker images for myocardial late gadolinium enhancement imaging using deep learning and a smartphone.

OBJECTIVES: To determine the optimal inversion time (TI) from Look-Locker scout images using a convolutional neural network (CNN) and to investigate the feasibility of correcting TI using a smartphone. METHODS: In this retrospective study, TI-scout images were extracted using a Look-Locker approach from 1113 consecutive cardiac MR examinations performed between 2017 and 2020 with myocardial late gadolinium enhancement. Reference TI null points were independently determined visually by an experienced radiologist and an experienced cardiologist, and quantitatively measured. A CNN was developed to evaluate deviation of TI from the null point and then implemented in PC and smartphone applications. Images on 4 K or 3-megapixel monitors were captured by a smartphone, and CNN performance on each monitor was determined. Optimal, undercorrection, and overcorrection rates using deep learning on the PC and smartphone were calculated. For patient analysis, TI category differences in pre- and post-correction were evaluated using the TI null point used in late gadolinium enhancement imaging. RESULTS: For PC, 96.4% (772/749) of images were classified as optimal, with under- and overcorrection rates of 1.2% (9/749) and 2.4% (18/749), respectively. For 4 K images, 93.5% (700/749) of images were classified as optimal, with under- and overcorrection rates of 3.9% (29/749) and 2.7% (20/749), respectively. For 3-megapixel images, 89.6% (671/749) of images were classified as optimal, with under- and overcorrection rates of 3.3% (25/749) and 7.0% (53/749), respectively. On patient-based evaluations, subjects classified as within optimal range increased from 72.0% (77/107) to 91.6% (98/107) using the CNN. CONCLUSIONS: Optimizing TI on Look-Locker images was feasible using deep learning and a smartphone. KEY POINTS: • A deep learning model corrected TI-scout images to within optimal null point for LGE imaging. • By capturing the TI-scout image on the monitor with a smartphone, the deviation of the TI from the null point can be immediately determined. • Using this model, TI null points can be set to the same degree as that by an experienced radiological technologist.

Image Quality of Submillimeter High-Spatial-Resolution 2D Late Gadolinium-enhanced Images in Cardiac MRI: A Feasibility Study.

Purpose: To evaluate the image quality of high-spatial-resolution two-dimensional (2D) late gadolinium enhancement (LGE) cardiac MRI compared with conventional normal-resolution LGE MRI. Materials and Methods: This prospective study included participants suspected of having cardiomyopathy who underwent cardiac MRI between March 2021 and December 2021. Normal-resolution and high-resolution 2D LGE sequences (inversion recovery [IR] and phase-sensitive inversion recovery [PSIR]) were performed at 3 T. Resolution was compared between normal-resolution and high-resolution images obtained in a quality assurance phantom. In vivo image quality and resolution were evaluated qualitatively using a five-point scoring system. Receiver operating characteristic curve analysis was used for LGE detection performance. Border sharpness was assessed with profile curve measurement. The contrast-to-noise ratio (CNR) between hyperenhancement and remote myocardium and LGE detection performance were calculated using normal-resolution IR images as the reference. Results: In total, 120 participants were evaluated (mean age, 56 years ± 17 [SD]; 72 men). Features smaller than 1 mm were detectable only on high-resolution images of the phantom. In vivo, the image resolution score with high-resolution LGE was 4.14-4.24, which was higher than the normal-resolution LGE reference score of 2.99 (P < .05). Border sharpness was higher in high-resolution images (P < .001). Receiver operating characteristic curve analysis revealed no evidence of a difference in LGE detection between normal-resolution and high-resolution images. There was also no evidence of a change in CNR of LGE in IR and PSIR magnitude compared with reference images. Conclusion: Comparison of image quality in 2D high-resolution and normal-resolution LGE cardiac MRI demonstrated the highest resolution for high-resolution IR and high-resolution PSIR magnitude sequences.Keywords: Cartilage Imaging, MRI, Cardiac, Heart, Imaging Sequences, Comparative Studies Supplemental material is available for this article. © RSNA, 2022.

Subclavian artery pseudoaneurysm long after the division of modified Blalock-Taussig shunt.

A massive but asymptomatic left subclavian artery pseudoaneurysm was diagnosed in a 30-year-old female patient with transposition of the great arteries, ventricular septal defect, and pulmonary atresia. After undergoing bilateral modified Blalock-Taussig shunts at the age of 4 months and 3 years, respectively, she underwent the Rastelli operation and division of both shunts at the age of 6 years of age. The pseudoaneurysm was not discovered at the follow-up investigation at age 14. During the time period from age 18 to 30 years, she was lost to follow-up, she was confirmed to be free from infectious disease, traumatic accident, or vasculitis. Pregnancy-induced hypertension was not associated during her pregnancy. Graft replacement of the left subclavian artery and redo right ventricular outflow tract reconstruction were successfully performed under deep hypothermic circulatory arrest at the age of 33 years.

Successful Conservative Treatment of Mycotic Pulmonary Artery Aneurysms Caused by MRSA Bacteremia.

Mycotic pulmonary artery aneurysms (MPAAs) are rare and life-threatening with currently no recommended treatment strategies. In this report, we describe a successfully treated case of ventricular septal defect in an 11-month-old girl who developed bacteremia, infective endocarditis, and MPAA caused by methicillin-resistant Staphylococcus aureus (MRSA). We first started vancomycin, gentamycin, and panipenem-betamipron for infective endocarditis but switched to teicoplanin and arbekacin on day 3 after initiating treatment because bacteremia persisted, and vancomycin minimum inhibitory concentration was relatively high at 2 mg/L. Although we added clindamycin on day 5 and fosfomycin on day 7, MRSA bacteremia persisted, and we finally added daptomycin at 10 mg/kg per day on day 8, whereupon the bacteremia subsided within a day. Although the bacteremia subsided, the patient developed septic pulmonary embolisms and septic arthritis on her left knee. We continued daptomycin but switched the concomitant drug to linezolid, trimethoprim-sulfamethoxazole, and rifampicin on day 11. After several repeats of puncture and lavage of her knee joint, she became afebrile on day 16. Computed tomography scans taken on day 32 revealed right pulmonary artery MPAAs. She was treated with long-term multidrug therapy, and MPAAs were absent on subsequent computed tomography scans on day 184. Multidrug therapy mainly based on daptomycin could be a possible salvage therapy for refractory MRSA bacteremia with high vancomycin minimum inhibitory concentration. Conservative treatment should be selectively considered as a treatment option for clinically stable MPAA instead of surgical and endovascular treatment.

Positive pediatric exercise capacity trajectory predicts better adult Fontan physiology rationale for early establishment of exercise habits.

OBJECTIVE: Exercise training is recommended for its possible favorable effects on Fontan pathophysiology. This study aimed to elucidate the impact of pediatric exercise capacity trajectory, which may mimic the effect of exercise training, on late adult Fontan pathophysiology. METHODS: Since 1990, 97 Fontan patients had consecutively undergone two serial cardiopulmonary exercise tests (CPX1 and CPX2) during childhood (ages 8 ±â€¯2 and 14 ±â€¯2 years) and one during adulthood (CPX3; age 23 ±â€¯5 years). The changes in peak oxygen uptake (PVO2: % of normal value) from CPX1 to CPX2 (1-dPVO2) and from CPX2 to CPX3 (2-dPVO2) were calculated, and then the patients were divided into four subgroups according the 1-dPVO2 and 2-dPVO2. RESULTS: In their adulthood, when compared with groups with negative 1-dPVO2, the central venous pressure, plasma brain natriuretic peptide level, and renal resistive index were lower, whereas liver synthetic function, body fat-free percentage, and PVO2 were higher in those with positive 1-dPVO2 (p < 0.05-0.0001). However, these favorable associations of 2-d-PVO2 with adult Fontan pathophysiology were not observed, except for the PVO2. After CPX3, 13 unexpected events occurred, and the risk was 76% lower in the groups having positive 1-dPVO2 than in those with negative 1-dPVO2 (hazard ratio, 0.24; 95% confidence interval, 0.09-0.62; p = 0.0035). CONCLUSIONS: A positive exercise capacity trajectory during childhood predicts better adult Fontan pathophysiology, including better prognosis. Thus, prescription of exercise could be a promising strategy in the management of pediatric Fontan patients.