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 technology implementations. 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.

A rare case of coronary fistula evaluated by first-pass radionuclide angiography.

Coronary artery fistula (CAF) is a rare anomaly that originates from the coronary artery and drains into the cardiac chamber or the adjacent vasculature. We report a case of CAF in a 77 years old woman with dyspnea on exertion. Using coronary angiography and cardiac multidetector computed tomography, this patient was diagnosed with CAF draining into the left bronchial arteries. First-pass radionuclide angiography (FPRNA) showed early pulmonary recirculation through a left to right shunt. The pulmonary to systemic blood flow ratio was 1.24. The patient received supportive care with vasodilator and antiplatelet therapy. First-pass radionuclide angiography was used to provide physiologic informations, to plan the treatment course for this patient.

Differential association between metabolic syndrome and coronary artery disease evaluated with cardiac computed tomography according to the presence of diabetes in a symptomatic Korean population.

BACKGROUND: Metabolic syndrome (MetS) is associated with increased risks of diabetes and coronary artery disease (CAD). Despite the controversial inclusion of established diabetes in MetS, the association between MetS and CAD according to diabetes status has not been elucidated in the Asian population. METHODS: We evaluated the association between MetS and CAD using the parameters including any plaque, obstructive plaque, and coronary artery calcium score (CACS) >100 according to diabetes status in 2,869 symptomatic Korean subjects who underwent cardiac computed tomographic angiography. RESULTS: The prevalence of MetS was significantly higher in the diabetic subjects than in the non-diabetic subjects (69% vs. 34%, P <0.001). The incidence of any plaque (64% vs. 43%, P <0.001), obstructive plaque (26% vs. 13%, P = 0.006), and CACS >100 (23% vs. 12%, P = 0.012) was significantly higher in diabetic subjects than in non-diabetic subjects. Among the MetS components, decreased high-density lipoprotein level was significantly associated with any plaque (odds ratio [OR] 1.35), obstructive plaque (OR 1.55), and CACS >100 (OR 1.57) in the non-diabetic subjects (P <0.01, respectively). However, none of the MetS components were associated with all the parameters in the diabetic subjects. Multivariate regression analysis revealed that MetS and the number of MetS components (MetSN) were independently associated with any plaque (MetS: OR 1.55, P <0.001; MetSN: OR 1.22, P <0.001), obstructive plaque (MetS: OR 1.52, P = 0.003; MetSN: OR 1.25, P <0.001), and CACS >100 (MetS: OR 1.46, P = 0.015; MetSN: OR 1.21, P = 0.004) only in the non-diabetic subjects, respectively. CONCLUSIONS: MetS was independently associated with the presence and severity of CAD only in the non-diabetic subjects among the symptomatic Korean population.

Association between Preoperative 18-FDG PET-CT SUVmax and Next-Generation Sequencing Results in Postoperative Ovarian Malignant Tissue in Patients with Advanced Ovarian Cancer.

This study investigated the association between maximum standardized uptake values (SUVmax) on preoperative 18-FDG PET-CT and next-generation sequencing (NGS) results in post-surgical ovarian malignant tissue in patients with advanced ovarian cancer. Twenty-five patients with stage IIIC or IV ovarian cancer who underwent both preoperative 18-FDG PET-CT and postoperative NGS for ovarian malignancies were retrospectively enrolled. Two patients had no detected variants, 21 of the 23 patients with any somatic variant had at least one single nucleotide variant (SNV) or insertion/deletion (indel), 10 patients showed copy number variation (CNV), and two patients had a fusion variant. SUVmax differed according to the presence of SNVs/indels, with an SUVmax of 13.06 for patients with ≥ 1 SNV/indel and 6.28 for patients without (p = 0.003). Seventeen of 20 patients with Tier 2 variants had TP53 variants, and there was a statistically significant association between SUVmax and the presence of TP53 variants (13.21 vs. 9.35, p = 0.041). Analysis of the correlation between the sum of the Tier 1 and Tier 2 numbers and SUVmax showed a statistically significant correlation (p = 0.002; Pearson's r = 0.588). In conclusion, patients with advanced ovarian cancer with SNVs/indels on NGS, especially those with TP53 Tier 2 variants, showed a proportional association with tumor SUVmax on preoperative PET-CT.

Faster Region-Based Convolutional Neural Network in the Classification of Different Parkinsonism Patterns of the Striatum on Maximum Intensity Projection Images of [18F]FP-CIT Positron Emission Tomography.

The aim of this study was to compare the performance of a deep-learning convolutional neural network (Faster R-CNN) model to detect imaging findings suggestive of idiopathic Parkinson's disease (PD) based on [18F]FP-CIT PET maximum intensity projection (MIP) images versus that of nuclear medicine (NM) physicians. The anteroposterior MIP images of the [18F]FP-CIT PET scan of 527 patients were classified as having PD (139 images) or non-PD (388 images) patterns according to the final diagnosis. Non-PD patterns were classified as overall-normal (ONL, 365 images) and vascular parkinsonism with definite defects or prominently decreased dopamine transporter binding (dVP, 23 images) patterns. Faster R-CNN was trained on 120 PD, 320 ONL, and 16 dVP pattern images and tested on the 19 PD, 45 ONL, and seven dVP patterns images. The performance of the Faster R-CNN and three NM physicians was assessed using receiver operating characteristics curve analysis. The difference in performance was assessed using Cochran's Q test, and the inter-rater reliability was calculated. Faster R-CNN showed high accuracy in differentiating PD from non-PD patterns and also from dVP patterns, with results comparable to those of NM physicians. There were no significant differences in the area under the curve and performance. The inter-rater reliability among Faster R-CNN and NM physicians showed substantial to almost perfect agreement. The deep-learning model accurately differentiated PD from non-PD patterns on MIP images of [18F]FP-CIT PET, and its performance was comparable to that of NM physicians.

A 4-Year Follow-Up of Subjects with Visually Equivocal Amyloid Positron Emission Tomography Findings from the Alzheimer's Disease Neuroimaging Initiative Cohort.

BACKGROUND: To date, the clinical significance of visually equivocal amyloid positron emission tomography (PET) has not been well established. OBJECTIVE: We studied the clinical significance of equivocal amyloid PET images from the Alzheimer's Disease Neuroimaging Initiative (ADNI). METHODS: Subjects with F-18 florbetapir PET scans at baseline who were followed up for 4 years were selected. Clinical characteristics, imaging biomarkers, cognitive function, and rate of conversion to AD were compared in subjects with visually equivocal findings. RESULTS: Of 249 subjects who completed the follow-up, 153 (61.4%), 20 (8.0%), and 129 (30.5%) were F-18 florbetapir-negative, -equivocal, and -positive, respectively. The mean standardized uptake value ratios (SUVR) of F-18 florbetapir PET were 0.75 ± 0.04, 0.85 ± 0.10, and 1.00 ± 0.09 for each group (p <0.001 between groups), and 15.0%, 70.0%, and 98.7% of patients were quantitatively above the positive threshold. The change in the SUVR of F-18 florbetapir PET was higher in the equivocal (6.09 ± 3.61%, p <0.001) and positive (3.13 ± 4.38%, p <0.001) groups than the negative group (0.88 ± 4.28%). Among the subjects with normal or subjective memory impairment and mild cognitive impairment, 5.3% with negative amyloid PET and 37.5% with positive amyloid PET converted to AD over the 4-year period. None of the equivocal amyloid PET subjects converted to AD during this period. CONCLUSION: Approximately 8% of subjects from the ADNI cohort showed visually equivocal amyloid PET scans with intermediate load and rapid accumulation of amyloid, but did not convert to AD during the 4-year follow-up.

Prognostic value of metabolic parameters on 18F-fluorodeoxyglucose positron tomography/computed tomography in classical rectal adenocarcinoma.

We aimed to investigate the prognostic value of the metabolic parameters of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in classical rectal adenocarcinoma (CRAC). We retrospectively reviewed 149 patients with CRAC who underwent preoperative 18F-FDG PET/CT at initial diagnosis followed by curative surgical resection. 18F-FDG PET/CT metabolic parameters including maximum standardized uptake value (SUVmax), metabolic tumour volume (MTV), and total lesion glycolysis (TLG) for disease-free survival (DFS) and overall survival (OS) were evaluated for prognostic significance by univariate and multivariate analyses, along with conventional risk factors including pathologic T (pT) stage, lymph node (LN) metastasis, lymphovascular invasion (LVI), perineural invasion (PNI), and preoperative carcinoembryonic antigen (CEA) level. On univariate analysis, high pT stage, positive LN metastasis, LVI, PNI, MTV, and TLG were significant prognostic factors affecting DFS (all P < 0.05), while CEA level, high pT stage, positive LN metastasis, LVI, PNI, MTV, and TLG affected OS (all P < 0.05). On multivariate analysis, positive LN metastasis, LVI, MTV, and TLG were independent prognostic factors affecting DFS (all P < 0.05), while CEA level, positive LN metastasis, and MTV affected OS (all P < 0.05). Thus, the volume-based metabolic parameters from preoperative 18F-FDG PET/CT scans are independent prognostic factors in patients with CRAC.

Relationship Between Thyroid Hormone Levels and the Pathology of Alzheimer's Disease in Euthyroid Subjects.

Background: Although several studies have reported an association between thyroid dysfunction and Alzheimer's disease (AD), the effect of mild thyroid dysfunction within the normal range of thyrotropin (TSH) on the development of AD remains unclear. The aim of this study was to evaluate the association between thyroid hormones and the pathology of AD in euthyroid subjects. Methods: Sixty-nine subjects with a TSH level between 0.5 and 4.5 µIU/L who underwent 18F-florbetaben positron emission tomography were included in this prospective cross-sectional study. The levels of serum free thyroxine (fT4) and TSH were quantified using radioimmunoassay. Neuropsychological tests were performed to assess cognitive function. Differences in cerebral amyloid-ß (Aß) burden were compared between high-normal TSH (TSH ≥2.5 µIU/mL) and low-normal TSH (TSH <2.5 µIU/mL) groups. Multiple linear regression analyses, adjusted for age, sex, education level, and Neuropsychiatric Inventory scores, were performed to evaluate relationships between thyroid hormone levels and both cerebral Aß burden and cognitive function. Results: The cerebral Aß burden in the high-normal TSH group was significantly higher than in the low-normal TSH group (1.53 ± 0.31 vs. 1.35 ± 0.22, p = 0.009). The fT4 levels were negatively correlated with cerebral Aß burden (ß = -0.240, p = 0.035), and TSH levels were positively correlated with cerebral Aß burden (ß = 0.267, p = 0.020). The fT4 level was also positively associated with cognitive function, as inferred from neuropsychological test scores. Conclusions: Thyroid hormone concentrations were associated with AD pathology in euthyroid subjects. Our findings suggest that AD is likely to occur even in individuals with high-normal TSH levels.

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

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.

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.

Clinical significance of visually equivocal amyloid PET findings from the Alzheimer's Disease Neuroimaging Initiative cohort.

To evaluate the clinical and imaging characteristics of patients with visually equivocal amyloid PET images, patients from the Alzheimer's Disease Neuroimaging Initiative cohort who had fluorine-18-florbetapir PET scans both at baseline and 24 months were selected. Five nuclear medicine physicians visually assessed the PET images and classified them as either positive or negative. Images not reaching a majority agreement were classified as equivocal. Among a total of 379 patients, the number of patients in each fluorine-18-florbetapir PET negative/equivocal/positive categories was 218 (57.5%), 32 (8.4%), and 129 (34.0%). Eight to 9% of patients with normal cognition (N=12/141), mild cognitive impairment (N=20/214), and no Alzheimer's disease (N=0/24) showed equivocal PET finding for each. In negative/equivocal/positive groups, positive cerebrospinal fluid Aß1-42 was observed in 25.7, 81.5, and 98.3%, respectively. Baseline standardized uptake value ratios of fluorine-18-florbetapir PET were 0.75±0.05, 0.86±0.09, and 1.01±0.09, respectively [F(2, 376)=603.547; P<0.001]. After 24 months of follow-up, the standardized uptake value ratios increased by 0.81±2.62, 2.81±2.90, and 2.17±3.66%, respectively [F(2, 376)=7.905, P<0.05 vs. the negative group]. Among mild cognitive impairment patients, the equivocal group showed a more rapid decline in glucose metabolism than the negative group [5.52±5.36 vs. 0.67±4.45; F(2, 122)=9.028, P<0.01]. 8.4% of the patients in this study showed a visually equivocal result of amyloid PET. These patients showed a moderate amount of amyloid accumulation and a rapid rate of accumulation.

Colonic Parasitic Infection Mimicking Peritoneal Seeding on 18F-FDG PET/CT.

A 77-year-old man with anorexia and weight loss for 6 months received a diagnosis of gastric cancer by endoscopy and referred for F-FDG PET/CT for initial staging. F-FDG PET/CT showed multiple foci of increased FDG uptake with diffuse wall thickening and multiple diverticula. The differential diagnoses were peritoneal seeding and multiple diverticulitis. The patient underwent curative total gastrectomy, and the lesion was diagnosed as poorly differentiated adenocarcinoma by histological examination. He underwent anterior resection of the sigmoid colon for exploration. The nodular lesions of the sigmoid colon were diagnosed by histopathologic examination as chronic diverticulitis caused by a parasitic infection.

Diagnostic accuracy of 18F-FDG PET/CT for detecting synchronous advanced colorectal neoplasia in patients with gastric cancer.

Preoperative screening for synchronous colorectal neoplasia (CRN) has been recommended in patients with gastric cancer because patients with gastric cancer are at increased risk for synchronous CRN. The aim of this study was to investigate the diagnostic accuracy of F-fluorodeoxyglucose (F-FDG) positron emission tomography/computed tomography (PET/CT) for detecting synchronous advanced CRN in patients with gastric cancer.A total of 256 patients who underwent colonoscopy and F-FDG PET/CT for preoperative staging were enrolled in this study. The diagnosis of focal colonic F-FDG uptake on F-FDG PET/CT image was made based on histopathologic results from the colonoscopic biopsy. The F-FDG PET/CT result was considered as true positive for advanced CRN when focal F-FDG uptake matched colorectal carcinoma or adenoma with high-grade dysplasia in the same location on colonoscopy.Synchronous advanced CRN was detected in 21 of the 256 patients (4.7%). Sensitivity, specificity, and accuracy of F-FDG PET/CT were 76.2%, 96.2%, and 94.5%. The size of CRN with a true positive result was significantly larger than that with a false negative result.F-FDG PET/CT demonstrated high diagnostic accuracy for detecting synchronous advanced CRN in patients with gastric cancer. Colonoscopy is recommended as the next diagnostic step for further evaluation of a positive F-FDG PET/CT result in patients with gastric cancer.

Evaluation of the predictive value of coronary artery calcium score for obstructive coronary artery disease in asymptomatic Korean patients with type 2 diabetes mellitus.

BACKGROUND: Compared with coronary computed tomographic angiography (CCTA), the coronary artery calcium score (CACS) may be limited in predicting adverse cardiovascular events in asymptomatic diabetic patients. METHODS: We evaluated the predictive value of CACS for obstructive coronary plaques (OCPs) assessed by CCTA in 328 consecutive asymptomatic patients with type 2 diabetes mellitus who had an estimated glomerular filtration rate greater than 60 ml/min/1.73 m². RESULTS: In total, 29 (9%) patients had OCPs: calcified or mixed OCPs and noncalcified OCPs were found in 26 (8%) and three (1%) patients, respectively. On the basis of a CACS of 0, 1-10, 11-100, and greater than 100, OCPs were found in 2, 5, 15, and 36% of patients, respectively. On receiver operating characteristic curve analysis, the optimal cutoff CACS for predicting OCPs was found to be 33, with 83% sensitivity and 81% specificity (area under the curve, 0.853; 95% confidence interval, 0.777-0.930; P<0.001). Positive and negative predictive values of a CACS of 33 for OCPs were 30 and 98%, respectively. On multivariate logistic regression analysis, age [odds ratio (OR), 1.09], microalbuminuria (OR, 3.43), current smoking (OR, 3.93), and CACS greater than 33 (OR, 15.85) were found to be independently associated with an increased risk for OCPs (P<0.05, respectively). The predictive significance of CACS greater than 33 for OCPs improved after considering the status of microalbuminuria and current smoking. CONCLUSION: These findings suggest that CACS is an effective gatekeeper for evaluating obstructive coronary artery disease using CCTA in asymptomatic Korean patients with type 2 diabetes mellitus who have near-normal kidney function.

Differential association between obesity and coronary artery disease according to the presence of diabetes in a Korean population.

BACKGROUND: Coronary artery disease (CAD) is a major cardiovascular complication in diabetic patients. Despite the significant association between obesity and diabetes, the majority of the diabetic subjects are not obese in an Asian population. This study evaluated the association between obesity and coronary artery disease (CAD) according to the diabetes status in a Korean population. METHODS: The association between obesity and CAD using the parameters of any plaque, obstructive plaque, and coronary artery calcium score (CACS) >100 according to the presence of diabetes was evaluated in 7,234 Korean adults who underwent multi-detector computed tomography for general health evaluations. Obesity was defined as a body mass index (BMI) ≥25 kg/m(2). RESULTS: The prevalence of obesity was significantly higher in diabetic subjects than in non-diabetic subjects, but the majority of the diabetic subjects were non-obese (48% vs. 37%, p <0.001). The incidence of any plaque (58% vs. 29%), obstructive plaque (20% vs. 6%), and CACS >100 (20% vs. 6%) were significantly higher in diabetic patients than in non-diabetic subjects (p <0.001, respectively). Incidence of any plaque (33% vs. 26%, p <0.001), obstructive plaque (7% vs. 6%, p = 0.014), and CACS >100 (8% vs. 6%, p = 0.002) was significantly higher in non-diabetic subjects with obesity than in those without obesity, but the incidence of all coronary parameters was not different in diabetic subjects according to the obesity status. After adjusting for confounding risk factors including age, gender, hypertension, dyslipidemia, current smoking, and mild renal dysfunction, obesity was independently associated with increased risks of any plaque (OR 1.14) and CACS >100 (OR 1.31) only in non-diabetic subjects (p <0.05, respectively). Multiple logistic regression models revealed that diabetes was independently associated with all coronary parameters. CONCLUSION: Despite a significantly higher prevalence of obesity in diabetic subjects than in non-diabetic subjects, obesity is associated with the presence of any plaque and severe coronary calcification only in subjects without established diabetes among Korean population.

Eosinophilic infiltration in the colon and liver mimicking primary colon cancer with hepatic metastases on (18)F-FDG PET/CT.

We describe the case of a 78-year-old man presenting with abdominal pain and a weight loss of 5 kg over 2 months. Colonoscopy and abdominal CT suggested colon cancer of hepatic flexure. F-FDG PET/CT scan showed moderate FDG uptake lesion at the hepatic flexure colon and multiple foci of FDG accumulation in the liver. These were considered as colon cancer with multiple hepatic metastases. However, the pathologic finding of colonoscopic biopsy and CT-guided liver biopsy showed only eosinophilic infiltration and no evidence of malignancy.

Simultaneous splenic and colonic metastases from gastric cancer: different FDG avidities according to the density of cancer cells imaged on FDG PET/CT.

We describe the ¹8F-FDG PET/CT findings of 2 simultaneous metastatic gastric cancers to the colon and spleen with quite different FDG avidities. Longitudinal and weak FDG uptake was observed in the descending colon; therefore, it could not be distinguished from nonpathological functional uptake of normal colon. Meanwhile, the splenic mass showed intense uptake. Contrast-enhanced CT revealed a segmental wall thickening of the descending colon as well as a hypoattenuating splenic mass suggesting metastases. Splenectomy and left hemicolectomy were performed. Histological diagnosis disclosed metastatic gastric cancer. The differential diagnoses and review of the literature are presented.