Artificial Intelligence in Health Care: Current Applications and Issues

In recent years, artificial intelligence (AI) technologies have greatly advanced and become a reality in many areas of our daily lives. In the health care field, numerous efforts are being made to implement the AI technology for practical medical treatments. With the rapid developments in machine learning algorithms and improvements in hardware performances, the AI technology is expected to play an important role in effectively analyzing and utilizing extensive amounts of health and medical data. However, the AI technology has various unique characteristics that are different from the existing health care technologies. Subsequently, there are a number of areas that need to be supplemented within the current health care system for the AI to be utilized more effectively and frequently in health care. In addition, the number of medical practitioners and public that accept AI in the health care is still low;moreover, there are various concerns regarding the safety and reliability of AI technologyimplementations. Therefore, this paper aims to introduce the current research and application status of AI technology in health care and discuss the issues that need to be resolved.

Evaluation of Flow Pattern in the Ascending Aorta in Patients with Repaired Tetralogy of Fallot Using Four-Dimensional Flow Magnetic Resonance Imaging

OBJECTIVE: To evaluate flow pattern characteristics in the ascending aorta (AA) with four-dimensional (4D)-flow MRI and to determine predictors of aortic dilatation late after tetralogy of Fallot (TOF) repair. MATERIALS AND METHODS: This study included 44 patients with repaired TOF (25 males and 19 females; mean age, 28.9 ± 8.4 years) and 11 volunteers (10 males and 1 female, mean age, 33.7 ± 8.8 years) who had undergone 4D-flow MRI. The aortic diameters, velocity, wall shear stress (WSS), flow jet angle (FJA), and flow displacement (FD) at the level of the sinotubular junction (STJ) and mid-AA were compared between the repaired TOF and volunteer groups. The hemodynamic and clinical parameters were also compared between the aortic dilatation and non-dilatation subgroups in the repaired TOF group. RESULTS: The diameters of the sinus of Valsalva, STJ, and AA were significantly higher in the repaired TOF group than in the volunteer group (p = 0.002, p < 0.001, and p = 0.013, respectively). The FJAs at the STJ and AA were significantly greater in the repaired TOF group (p < 0.001 and p = 0.003, respectively), while velocities and WSS parameters were significantly lower. FD showed no statistically significant difference (p = 0.817). In subgroup analysis, age at TOF repair was significantly higher (p = 0.039) and FJA at the level of the AA significantly greater (p = 0.003) and mean WSS were significantly lower (p = 0.039) in the aortic dilatation group. FD were higher in the aortic dilatation group without statistical significance (p = 0.217). CONCLUSION: Patients with repaired TOF have an increased FJA, dilated AA, and secondarily decreased WSS. In addition to known risk factors, flow eccentricity may affect aortic dilatation in patients with repaired TOF.

Reverse Warburg Effect-Related Mitochondrial Activity and ¹⁸F-FDG Uptake in Invasive Ductal Carcinoma / 대한핵의학회잡지

PURPOSE: We evaluated the relationship between fluorine-18 fluoro-2-deoxy-glucose (¹⁸F-FDG) uptake and mitochondrial activity in cancer cells and investigated the prognostic implications of this relationship in patients with invasive ductal carcinoma of the breast (IDCB).METHODS: One hundred forty-six patients with primary IDCB who underwent preoperative ¹⁸F-FDG PET/CT followed by curative surgical resection were enrolled in the current study. Mitochondrial activity of cancer cells was assessed based on translocase of outer mitochondrial membrane 20 (TOMM20) expression and cytochrome C oxidase (COX) activity. A Pearson's correlation analysis was used to assess the relationship between the maximum standardized uptake value of the primary tumour (pSUVmax) and mitochondrial activity. Clinicopathological factors, including pSUVmax, histological grade, oestrogen receptor (ER), progesterone receptor (PR), and TOMM20 expression; and COX activity, were assessed for the prediction of disease-free survival (DFS) using the Kaplan–Meier method and Cox proportional hazards model.RESULTS: Fourteen of the 146 subjects (9.6%) showed tumour recurrence. There was a significant positive correlation between ¹⁸F-FDG uptake and the mitochondrial activity of cancer cells in patients with IDCB, and increased ¹⁸F-FDG uptake and mitochondrial activity were significantly associated with a shorter DFS. Additionally, results from the receiver-operating curve analysis demonstrated that the cut-off values of pSUVmax, TOMM20 expression, and COX activity for the prediction of DFS were 7.76, 4, and 5, respectively. Further, results from the univariate analysis revealed that pSUVmax, TOMM20 expression, PR status, and histologic grade were significantly associated with DFS; however, the multivariate analysis revealed that only pSUVmax was associated with DFS (HR, 6.51; 95% CI, 1.91, 22.20; P = 0.003).CONCLUSIONS: The assessment of preoperative ¹⁸F-FDG uptake and post-surgical mitochondrial activity may be used for the prediction of DFS in patients with IDCB.

Reverse Warburg Effect-Related Mitochondrial Activity and ¹⁸F-FDG Uptake in Invasive Ductal Carcinoma / 대한핵의학회잡지

PURPOSE@#We evaluated the relationship between fluorine-18 fluoro-2-deoxy-glucose (¹⁸F-FDG) uptake and mitochondrial activity in cancer cells and investigated the prognostic implications of this relationship in patients with invasive ductal carcinoma of the breast (IDCB).@*METHODS@#One hundred forty-six patients with primary IDCB who underwent preoperative ¹⁸F-FDG PET/CT followed by curative surgical resection were enrolled in the current study. Mitochondrial activity of cancer cells was assessed based on translocase of outer mitochondrial membrane 20 (TOMM20) expression and cytochrome C oxidase (COX) activity. A Pearson's correlation analysis was used to assess the relationship between the maximum standardized uptake value of the primary tumour (pSUVmax) and mitochondrial activity. Clinicopathological factors, including pSUVmax, histological grade, oestrogen receptor (ER), progesterone receptor (PR), and TOMM20 expression; and COX activity, were assessed for the prediction of disease-free survival (DFS) using the Kaplan–Meier method and Cox proportional hazards model.@*RESULTS@#Fourteen of the 146 subjects (9.6%) showed tumour recurrence. There was a significant positive correlation between ¹⁸F-FDG uptake and the mitochondrial activity of cancer cells in patients with IDCB, and increased ¹⁸F-FDG uptake and mitochondrial activity were significantly associated with a shorter DFS. Additionally, results from the receiver-operating curve analysis demonstrated that the cut-off values of pSUVmax, TOMM20 expression, and COX activity for the prediction of DFS were 7.76, 4, and 5, respectively. Further, results from the univariate analysis revealed that pSUVmax, TOMM20 expression, PR status, and histologic grade were significantly associated with DFS; however, the multivariate analysis revealed that only pSUVmax was associated with DFS (HR, 6.51; 95% CI, 1.91, 22.20; P = 0.003).@*CONCLUSIONS@#The assessment of preoperative ¹⁸F-FDG uptake and post-surgical mitochondrial activity may be used for the prediction of DFS in patients with IDCB.

F-18 FDG PET/CT Finding in Solid Pseudo-papillary Tumor of the Pancreas 6 years After Initial Diagnosis / 핵의학분자영상

Solid pseudo-papillary tumor (SPT) is a rare pancreatic neoplasm with low malignant potential, which tends to occur predominantly in younger females. Only a few cases of SPT seen on F-18 FDG PET scan have been reported, and the findings are not fully evaluated. A 33 year-old woman underwent F-18 FDG PET/CT study for staging of renal cell carcinoma. She was diagnosed with SPT of the pancreas 6 years ago, and has not had any treatment so far. Recent PET/CT showed marked F-18 FDG uptake in the peripheral solid portion and relatively less F-18 FDG uptake to the central calcified portion of SPT. We report one case of SPT of the pancreas on F-18 FDG PET/CT.

Etiologic Evaluation of Ischemic Mitral Regurgitation Using Cardiac MRI

BACKGROUND AND OBJECTIVES: To evaluate the 3 dimensional geometric changes and the effect of revascularization in patients with ischemic mitral regurgitation (IMR), using cardiac magnetic resonance imaging (MRI). SUBJECTS AND METHODS: Twenty-three patients with IMR, 10 with dilated cardiomyopathy with MR (DCM-MR) and 7 control subjects were enrolled. Hemodynamic indices, severity of MR, geometric parameters of mitral apparatus and myocardial viability were evaluated in all patients, and re-evaluated in the IMR patients 6 months after the revascularization. RESULTS: The mitral tenting area (TAA) (334.1+/-11.7 mm2 vs. 222.9+/-23.0 mm2, p=0.16) and the sum of the tenting angles (TA) (72.9+/-2.9degreevs. 51.5+/-1.1degree p<0.001) at the mid-systolic phase were increased in the IMR compared to the DCM-MR patients. In the IMR patients, the MR severity was positively correlated with the sum of the tethering lengths (r=0.522, p=0.011), LVESV (r=0.551, p=0.006), TAA (r=0.613, p=0.002) and TA (r=0.713, p<0.001). Of the 10 patients with viable myocardium, who had been revascularized without surgical repair of the mitral apparatus, the MR severity was decreased (28.3+/-0.4% vs. 16.5+/-.6%, p=0.009) in 7 patients, with decreases in the sum of the tethering distances (51.2+/-3.9 mm vs. 40.2+/-.1 mm, p=0.034), tenting area (299.2+/-3.8 mm2 vs. 215.0+/-3.6 mm2, p=0.036) and sum of the tenting angles (72.9+/-2.9degreevs. 56.2+/-4.8degree, p=0.015) 6 months after the revascularization. CONCLUSION: IMR was related with the geometric change in the mitral apparatus. Cardiac MRI can be an effective tool for evaluating these geometric changes and when formulating a treatment plan.

Measurement of Perfusion of Pulmonary Nodules by Electron Beam Tomography

PURPOSE: To investigate the perfusion of pulmonary nodules and the flow pattern revealed by electron beam tomography (EBT), and to evaluate their usefulness in the differential diagnosis of pulmonary nodules. MATERIALS AND METHODS: A prospective perfusion study involving 28 nodules in 23 men and five women (mean age, 57 years) was performed using EBT with the multislice flow mode. There were four phases. Precontrast density (Hounsfield units, HU) in phase 0; perfusion, peak HU and time to peak in phase 1; and mean HU and percentage decrease of HU to peak HU of phase 1 in phases 2 and 3 were measured and compared according to the diagnosis. RESULTS: Malignancy was diagnased in 19 cases [primary lung cancer (n=14); metastatic nodules (n=5)], while nine nodules were benign. Perfusion was significantly higher in malignant nodules than in benign (p<0.001) and a higher mean delay 1 HU (p<0.05) and a significantly short time to peak (p<0.05) were recorded in malignant nodules. In primary lung cancer cases, perfusion was significantly high compared with benign nodules (p<0.001), and a mean delay 1 HU was observed (p<0.05). There was no significant difference in perfusion between primary lung cancer and metastasis. CONCLUSION: Perfusion and flow pattern data measured by EBT can provide the useful information for differentiation between malignant and benign pulmonary nodules.

Measurement of Myocardial Perfusion with Electron Beam Tomography: Comparison with 99m Tc-MIBI Scan

PURPOSE: To compare the accuracy with which electron beam tomography (EBT) and 99m Tc-MIBI scanning measure myocardial perfusion valve. MATERIALS AND METHODS: Twenty-two subjects [normal volunteers (n = 6), patients in whom ischemic heart disease was diagnosed (n = 5), and those in whom ischemic heart disease was suspected but who were found to be normal (n = 11)] were involved in this study. EBT was performed after bolus injection of contrast media (50 ml of Iopamiro 370 or Optiray 350, 3 ml/sec). The myocardium was divided into 16 segments according to the classification devised by the American Society of Echocardiography, and each myocardial perfusion value was calculated by post-image processing. A pharmacologic stress test was performed in all subjects except four patients with acute myocardial infarction, and myocardial perfusion reserve ratios were assessed. Single photon emission computed tomography (SPECT) was performed after the injection of 20 mCi of 99m Tc-MIBI. Any segments with moderate to severe photon defect on visual analysis of SPECT were identified and perfusion values determined by EBT in normal and ischemic segments were compared. RESULTS: No difference in myocardial perfusion was found between volunteers and the suspected group. Their perfusion values were 0.71 +/-0.14 ml/g/min in the resting state and 1.16 +/-0.24 ml/g/min on the stress test and the myocardial perfusion reserve ratio was, therefore, 1:1.68 +/-0.38. In ischemic patients, 99m Tc-MIBI scanning revealed a perfusion defect in 28 segments, and on EBT the measurement obtained was 0.54 +/-0.19 ml/g/min. The remaining 324 perfusion segments shown by SPECT to be normal showed a perfusion value of 0.79 +/-0.22 ml/g/min on EBT. CONCLUSION: Compared with 99mTc-MIBI scanning, the measurement of myocardial perfusion by EBT provides absolute quantification of perfusion value and more detailed anatomic information.

Evaluation of Conotruncal Anomalies by Electron Beam Tomography / 대한흉부외과학회지

BACKGROUND: To evaluate the diagnostic accuracy of EBT(Electron Beam Tomography) in the diagnosis of conotruncal anomaly and to determine whether it can be used as a substitute for cardiac angiography. MATERIAL AND METHOD: 20 patients(11M & 9F) with TOF(n=7, pulmonary atresia 2), DORV(n=7), complete TGV(n=4), & corrected TGV(n=2) were included. The age ranged from 7 days to 26 years(median 60 days). We analyzed the sequential chamber localization, the main surgical concenrn in each disease category (PA size, LVED volume and coronary artery pattern for TOF& pulmonary atresia, the LV mass, LVOT obstruction, coronary artery pattern for complete TGV, and type of VSD and TV-PV distance for DORV, etc) and other associated anomalies(e.g., VSD, arch anomalies, tracheal stenosis, etc). Those were compared with the results of echocardiography(n=19), angiography (n=9), and surgery(n=11). The interval between EBT and echocardiography/angiography was within 20/11 days, respectively except for an angiography in a patient with corrected TGV (48 days). RESULT: EBT correctly diagnosed the basic components of conotruncal anomalies in all subjects, compared to echocardiography, angiography or surgery. These included the presence, type and size of VSD(n=20), pulmonic/LV outflow tract stenosis(n=15/2), relation of great arteries and the pattern of the proximal epicardial coronary arteries(16 out of 20). EBT proved to be accurate in quantitation of the intrapericardial and hilar pulmonary arterial dimension and showed high correlation and no difference compared with echocardiography, angiography, or surgery(p>0.05) except for left pulmonary arterial & ascending arterial dimension by echocardiography. LVED volume in seven TOF(no difference: p>0.05 & high correlation: r=0.996 with echocardiography), and LV mass in 4 complete TGV were obtained. Additionally, EBT enabled the cdiagnosis of subjlottic tracheal stenosis and tracheal bronchus in 1 respectively. Some peripheral PA stenosis were not detected by echocardiography, while echocardiography appeared to be slightly more accurate than EBT in detecing ASD or PDA. CONCLUSIONS: EBT can be a non-invasive and accurate modality of for the evaluation of most anatomical alteration including peripheral PS or interruption in patients with conotruncal anomalies. Combined with echocardiography, EBT study provides sufficient information for the palliative or total repair of anomalies.

Accuracy of MR Imaging for Resectability of Extrahepatic Bile Duct Carcinoma

PURPOSE: To determine the accuracy of preoperative MR imaging for evaluation of resectability of extrahepaticbile duct carcinoma. MATERIALS AND METHODS: Thirty-four patients with proven extrahepatic bile duct carcinomaunderwent pre-operative MR imaging. All MR examinations were performed with a 1.5 T system, using a phased-arraymulticoil. Tumor resectability was prospectively determined by two radiologists who reached consensus. Tenpatients did not undergo surgery because the preoperative MR imaging, CT and endoscopic findings all indicatedunresectability. Twenty-five patients subsequently underwent surgical exploration, and their imaging andpathologic and laparotomic findings were compared. RESULTS: Twenty-two of 34 cases (65%) were resectable. Amongthe 22 cases resectable in laparotomy, pre-operative MR imaging had suggested that 20 were resectable, andsensitivity for resectability was thus 91%. Among the 22 cases in which MR imaging had suggested resectability,macroscopic clearance was complete in 20, giving a positive value of 91%. MR imaging underestimated portal venousor hepatic arterial invasion, and in one case missed small (<1 cm) hepatic metastases. In two cases, MR imagingoverestimated portal venous or hepatic arterial encasement. CONCLUSION: MR imaging is a useful diagnosticmodality for preoperative assessment of resectability of extrahepatic bile duct cancer.