Basics of Deep Learning: A Radiologist's Guide to Understanding Published Radiology Articles on Deep Learning.

Artificial intelligence has been applied to many industries, including medicine. Among the various techniques in artificial intelligence, deep learning has attained the highest popularity in medical imaging in recent years. Many articles on deep learning have been published in radiologic journals. However, radiologists may have difficulty in understanding and interpreting these studies because the study methods of deep learning differ from those of traditional radiology. This review article aims to explain the concepts and terms that are frequently used in deep learning radiology articles, facilitating general radiologists' understanding.

Gastrointestinal cancer risk in patients with a family history of gastrointestinal cancer.

BACKGROUND/AIMS: This study was performed to evaluate the relationship between family history of gastrointestinal (GI) cancers and incidence of any GI cancer in the Korean population. METHODS: Between January 2015 and July 2016, 711 GI cancer patients and 849 controls in 16 hospitals in Korea were enrolled. Personal medical histories, life styles, and family history of GI cancers were collected via questionnaire. RESULTS: There was a significant difference in the incidence of family history of GI cancer between GI cancer patients and controls (p=0.002). Patients with family history of GI cancer tended to be diagnosed as GI cancer at younger age than those without family history (p=0.016). The family members of GI cancer patients who were diagnosed before 50 years of age were more frequently diagnosed as GI cancer before the age of 50 years (p=0.017). After adjusting for major confounding factors, age (adjusted odds ratio [AOR] 1.065, 95% confidence interval [CI]; 1.053-1.076), male gender (AOR 2.270, 95% CI; 1.618-3.184), smoking (AOR 1.570, 95% CI; 1.130-2.182), and sibling's history of GI cancer (AOR 1.973, 95% CI; 1.246-3.126) remained independently associated with GI cancers. CONCLUSIONS: GI cancer patients tended to have a first relative with a history of concordant GI cancer. Personal factors (old age and male) and lifestyle (smoking) contribute to the development of GI cancer, independently. Individuals with high risk for GI cancers may be advised to undergo screening at an earlier age.

Metastatic endophthalmitis and thyroid abscess complicating Klebsiella pneumoniae liver abscess.

The thyroid is resistant to infection due to its anatomical and physiological characteristics. We present a rare case of invasive liver abscess with metastatic thyroid abscess and endogenous endophthalmitis in a previously healthy 55-year-old female patient without diabetes or other medical illness. This report raises an important question of the virulence of Klebsiella pneumoniae as an increasingly common causative agent of liver abscess.

Assessment of the Risk of Colorectal Cancer Survivors Developing a Second Primary Pancreatic Cancer.

BACKGROUND/AIMS: We aimed to investigate the incidence of second primary pancreatic cancer (PC) after colorectal cancer (CRC) and to identify risk factors associated with subsequent PC. METHODS: The observed incidence of a subsequent PC in patients with CRC was standardized using a population with CRC from the Korean Central Cancer Registry (KCCR). The expected incidence rate of PC was obtained by assuming that the select group experienced the same cancer incidence as the corresponding general population in the KCCR. RESULTS: The registry included 4,822 patients with CRC aged 45 to 74 years, representing 16,725.1 person-years of follow-up. Thirteen patients (0.3%) were diagnosed with a subsequent PC, and the overall age-adjusted incidence of second primary PC was 269.6 per 100,000 cases. In contrast, the overall incidence of primary PC in the general population was 18.68 per 100,000 individuals. The standardized incidence ratio of subsequent PC was 14.44, which was significantly higher in patients with CRC than in the general population. Sex, diabetes mellitus, smoking, body mass index, and a history of receiving chemotherapy as a treatment for CRC did not increase the risk of subsequent development of PC. CONCLUSIONS: The risk of a second primary PC was higher in patients with CRC. Further studies are needed to identify the risk factors and generate a screening strategy for cancer survivors.

[A Case of Isolated Leptomeningeal Carcinomatosis from Advanced Gastric Cancer].

Leptomeningeal carcinomatosis (LMC) is rare metastatic form of gastric cancer. Most cases are diagnosed in the final stage after multiple distant metastasis. An 84-year-old woman was admitted with melena, headache and vomiting. Esophagogastroduodenoscopy showed an ulceroinfiltrating lesion at the stomach (Borrmann class III), and biopsy revealed a signet ring cell carcinoma. The abdominal-pelvic CT showed no evidence of metastasis. A sudden decrease of consciousness was noted, but the brain CT showed no active lesion while the brain MRI revealed enhancement of leptomeninges. A lumbar puncture was performed and the cerebrospinal fluid study revealed malignant neoplastic cells. With family consent, no further evaluation and treatment were administered and she died six weeks after the diagnosis of gastric cancer. We report an extremely rare case of a patient who initially presented with neurologic symptoms, and was diagnosed LMC from advanced gastric cancer without any evidence of metastasis in abdomen and pelvis.

Folfox4 as a rescue chemotherapy for gemcitabine-refractory pancreatic cancer.

BACKGROUND/AIMS: This phase II study assessed the efficacy and safety of FOLFOX4 as a rescue therapy in patients with gemcitabine-refractory pancreatic cancer. METHODOLOGY: The study included patients with advanced pancreatic cancer who had failed gemcitabine-based chemotherapy. FOLFOX4 was administered biweekly as follows: oxaliplatin, 85 mg/m² as a 2-hour infusion (day 1); leucovorin, 200 mg/m²/day as a 2-hour infusion (days 1 and 2); 5-fluorouracil, bolus 400 mg/m²/day and 600 mg/m²/day as a 22-hour infusion (days 1 and 2). RESULTS: Forty-four patients received a total of 264 cycles of chemotherapy. There was 1 complete response (2.2%), 4 partial responses (9.1%), and 13 stable diseases (29.5%). The objective response rate was 11.4% and the tumor stabilization rate was 40.9%. The median time to progression was 9.9 weeks (95%CI: 8.2-11.5) and the median overall survival was 31.1 weeks (95%CI: 24.4-37.9). The common adverse events were hematologic toxicities: grade 3 or 4 neutropenia in 19 patients (43.2%), anemia in 9 patients (20.5%), and thrombocytopenia in 6 patients (13.5%). Grade 3 or 4 neuropathy occurred in 4 patients (9.1%). CONCLUSIONS: In gemcitabine-refractory pancreatic cancer, FOLFOX4 showed encouraging activity and was generally well-tolerated. However, careful attention needs to be paid to hematologic toxicities.

Acinetobacter baumannii infection was decreased by the structural renovation of a medical intensive care unit.

PURPOSE: The study aimed to determine whether improvements in intensive care unit (ICU) structural environment affect the incidence of ICU-acquired infections (IAIs), particularly those caused by multidrug-resistant pathogens. METHODS: The incidence of IAI and the number of infections caused by organisms during the 6 months immediately before ICU renovation and during the 6 months immediately after ICU renovation were compared. The observational duration was prolonged for an additional 1 year after recruiting the after-renovation data to observe if the found effect of ICU structural renovation is maintained. The relevant data were prospectively gathered. RESULTS: The overall IAI incidence and distribution of infection site showed no difference in both periods. In IAI-causing pathogens, no considerable difference was found between before and after renovation, except for Acinetobacter baumannii. In comparison of the major pathogens' identification rate between the entire hospital and the renovated ICU during the study periods, only A baumannii cases in the renovated ICU significantly decreased. However, the reduction of the IAI cases by A baumannii was not sustained for more than 1 year. CONCLUSIONS: These results suggest that structural ICU renovations only may not improve overall IAI incidence, except for transient decrease in IAI by A baumannii.

Clinical implications and risk factors of acute pancreatitis after cardiac valve surgery.

PURPOSE: Acute pancreatitis is one of the potentially lethal complications that occurs after cardiac surgery. We tried to identify risk factors for and the prognosis of acute pancreatitis after cardiac valve surgery with cardiopulmonary bypass. MATERIALS AND METHODS: We retrospectively analyzed a database of consecutive patients who underwent cardiac valve surgery with cardiopulmonary bypass between January 2005 and April 2010 at our institution. Patients were classified as having acute pancreatitis based on serum lipase concentration and clinical symptoms (lipase ≥ 180 U/L or ≥ 60 U/L with relevant symptoms). RESULTS: Of the 986 patients who underwent cardiac valve surgery with cardiopulmonary bypass, 58 (5.9%) patients developed post-operative pancreatitis. Post-operative hospital stay was significantly longer (29.7 ± 45.6 days vs. 12.4 ± 10.7 days, p = 0.005) and in-hospital mortality rate was higher (15.5% vs. 2.0%, p<0.001) in patients with post-operative pancreatitis than those without. Hypertension, chronic kidney disease, and peri-operative use of norepinephrine were identified as independent risk factors for developing pancreatitis after cardiac valve surgery. CONCLUSION: We found that acute pancreatitis after cardiac valve surgery requires longer hospitalization and increases the in-hospital mortality rate. Clinicians should be aware that patients could develop pancreatitis after cardiac valve surgery, especially in patients with hypertension and chronic kidney disease treated with norepinephrine.

Clinicopathologic features and outcomes of pancreatic cysts during a 12-year period.

OBJECTIVE: Pancreatic cysts are being detected more frequently with advances in abdominal imaging. We designed this study to identify the characteristics of pancreatic cysts upon long-term follow-up and to define the proper management of them. METHODS: We identified 1386 patients diagnosed with pancreatic cysts at our hospital from 1999 to 2010 and analyzed clinicopathologic data including radiological findings. RESULTS: At initial diagnosis, 515 patients (37.2%) were classified as being at high-risk for malignancy, and 247 patients (17.8%) underwent surgery identifying 128 borderline or malignant cysts (51.8%). Borderline or malignant cysts were associated with older age, male sex, elevated serum level of lipase, carcinoembryonic antigen (CEA) or carbohydrate antigen 19-9 (CA 19-9), and a dilated pancreatic duct. Long-term follow-up for at least 24 months revealed that most of cystic lesions unchanged in size but malignant transformation was observed in 7 patients. CONCLUSIONS: Most lesions with low or indeterminate risk did not changed in size during follow-up period, but one fifth of high-risk lesions were identified as borderline or malignant after surgery. Surgical resection should be performed in patients with high-risk cysts considering their clinical condition, and radiological follow-up of nonsurgically managed cysts should be continued for more than 6 years.

Clinical features and outcomes of primary hepatic neuroendocrine carcinomas.

BACKGROUND AND AIM: Primary hepatic neuroendocrine carcinomas (PHNECs) are extremely rare, with only about 150 cases having been reported in the English-language literature. Because of the rarity of PHNECs, its clinical features and treatment outcomes are not well understood. Here, we report our experiences with PHNECs. METHODS: We identified patients diagnosed with PHNEC and analyzed their demographics, baseline laboratory data, tumor characteristics, treatment modalities and outcomes. RESULTS: A total of 218 consecutive patients were identified with pathologically confirmed neuroendocrine carcinoma. Of these, 12 patients were diagnosed with PHNECs; the median age was 66.5 years (range, 37 to 80 years), and seven patients (58.3%) were male. Two patients who each had a single hepatic mass underwent curative surgical resection. One patient who was of inoperable status at the initial diagnosis because of multiple intrahepatic metastases showed a partial response after the ninth round of systemic chemotherapy and then underwent surgical resection. The median overall survival in the 12 patients was 16.5 months (range, 0.7 to 41.7 months). Three patients who underwent surgical treatment are alive without recurrence for 15.2 months, 18.0 months, and 36.9 months, respectively. CONCLUSIONS: Primary hepatic neuroendocrine carcinoma should be considered as a possible differential diagnosis in the management of hepatic tumors. The liver can be the primary origin of neuroendocrine tumors, and if the tumors are diagnosed as primary hepatic neuroendocrine tumors, surgical resection must be considered for curative treatment.

Safety of capsule endoscopy using human body communication in patients with cardiac devices.

BACKGROUND: The MiroCam (IntroMedic, Ltd., Seoul, Korea) is a small-bowel capsule endoscope that uses human body communication to transmit data. The potential interactions between cardiac devices and the capsule endoscope are causes for concern, but no data are available for this matter. AIM: This clinical study was designed to evaluate the potential influence of the MiroCam capsules on cardiac devices. METHODS: Patients with cardiac pacemakers or implantable cardiac defibrillators referred for evaluation of small bowel disease were prospectively enrolled in this study. Before capsule endoscopy, a cardiologist checked baseline electrocardiograms and functions of the cardiac devices. Cardiac rhythms were continuously monitored by 24-h telemetry during capsule endoscopy in the hospital. After completion of procedures, functions of the cardiac devices were checked again for interference. Images from the capsule endoscopy were reviewed and analyzed for technical problems. RESULTS: Six patients, three with pacemakers and three with implantable cardiac defibrillators, were included in the study. We identified no disturbances in the cardiac devices and no arrhythmias detected on telemetry monitoring during capsule endoscopy. No significant changes in the programmed parameters of the cardiac devices were noted after capsule endoscopy. There were no imaging disturbances from the cardiac devices on capsule endoscopy. CONCLUSIONS: Capsule endoscopy using human body communication to transmit data was safely performed in patients with cardiac pacemakers or implantable cardiac defibrillators. Images from the capsule endoscopy were not affected by cardiac devices. A further large-scale study is required to confirm the safety of capsule endoscopy with various types of cardiac devices.

Primary intestinal lymphangiectasia diagnosed by capsule endoscopy and double balloon enteroscopy.

Primary intestinal lymphangiectasia (PIL) is a rare disorder characterized by dilated intestinal lymphatics and the development of protein-losing enteropathy. Patients with PIL develop hypoalbuminemia, hypocalcemia, lymphopenia and hypogammaglobulinemia, and present with bilateral lower limb edema, fatigue, abdominal pain and diarrhea. Endoscopy reveals diffusely elongated, circumferential and polypoid mucosae covered with whitish enlarged villi, all of which indicate intestinal lymphangiectasia. Diagnosis is confirmed by characteristic tissue pathology, which includes dilated intestinal lymphatics with diffusely swollen mucosa and enlarged villi. The prevalence of PIL has increased since the introduction of capsule endoscopy. The etiology and prevalence of PIL remain unknown. Some studies have reported that several genes and regulatory molecules for lymphangiogenesis are related to PIL. We report the case of a patient with PIL involving the entire small bowel that was confirmed by capsule endoscopy and double-balloon enteroscopy-guided tissue pathology who carried a deletion on chromosome 4q25. The relationship between this deletion on chromosome 4 and PIL remains to be investigated.

Proteomic analysis of pancreatic juice for the identification of biomarkers of pancreatic cancer.

INTRODUCTION: Protein profiles of endoscopically collected pancreatic juice from normal, chronic pancreatitis patients and pancreatic cancer patients were compared to identify diagnostic biomarkers of pancreatic cancer. METHODS: Secretin was injected intravenously and pancreatic juice was collected via selective cannulation of the pancreatic duct during endoscopic retrograde cholangiopancreatography. Pancreatic juices consisting of three pooled samples for normal control, chronic pancreatitis, and pancreatic cancer patients were compared using two-dimensional gel electrophoresis, and the proteins were subsequently identified using MALDI-TOF-MS. RESULTS: Thirty-five protein spots were up-regulated twofold in pancreatic cancer compared with the levels in the normal controls, and 85 protein spots were present in pancreatic cancer samples but not in normal controls. After excluding spots that were also expressed in chronic pancreatitis, 26 protein spots that were up-regulated or only expressed in pancreatic cancer samples were identified. Among the identified proteins, we confirmed the expressions of BIG2, PRDX6, and REG1α in pancreatic cancer tissue using immunohistochemistry. ELISA showed that the serum level of REG1α was significantly higher in patients with pancreatic cancer than it was in the normal controls (P = 0.023). With the best cut-off value, the sensitivity and specificity of REG1α to differentiate normal and pancreatic cancer were 82.6 and 81.8%, compared with 69.6 and 100% for CA19-9. CONCLUSIONS: We have shown that pancreatic juice is a good source of pancreatic cancer tumor markers. Further studies are needed to determine the clinical implications of REG1α and other markers.

Endoscopic papillary balloon dilation for removal of choledocholithiasis: indications, advantages, complications, and long-term follow-up results.

Endoscopic papillary balloon dilation (EPBD) is an alternative method of endoscopic sphincterotomy (EST). Although concerns regarding post-procedure pancreatitis have been expressed, EPBD has come to be recognized as an effective and safe method for stone removal in specific cases. To analyze the proper indications, ideal methods, complications, and long-term follow-up results for EPBD, we reviewed articles about EPBD located through a search of the PubMed data base. We analyzed the ballooning methods, indications, results and complications of EPBD among the articles found and compared the results with those of EST. We considered the authors' own clinical experience and knowledge in developing recommendations for EPBD. EPBD showed similar efficacy and safety for the removal of choledocholithiasis to that of EST. Although large or multiple stones were difficult to remove by EPBD, it was safer and easier to apply in patients with coagulopathy or abnormal anatomy. To prevent severe pancreatitis, excessive ballooning and impractical cannulation should be avoided, and precut sphincterotomy or adjuvant prophylaxis should be considered. Due to its preservation of the sphincter of Oddi, EPBD is expected to have fewer long-term complications, such as stone recurrence, cholangitis and cholecystitis. In conclusion, EPBD appears to be safe and effective for the treatment of choledocholithiasis with proper selection of ballooning methods and patients.

Placement of a fully covered self-expandable metal stent in a young patient with chronic pancreatitis.

Plastic stent insertion is a treatment option for pancreatic duct stricture with chronic pancreatitis. However, recurrent stricture is a limitation after removing the plastic stent. Self-expandable metal stents have long diameters and patency. A metal stent has become an established management option for pancreatic duct stricture caused by malignancy but its use in benign stricture is still controversial. We introduce a young patient who had chronic pancreatitis and underwent several plastic stent insertions due to recurrent pancreatic duct stricture. His symptoms improved after using a fully covered self-expandable metal covered stent and there was no recurrence found at follow-up at the outpatient department.

Development and validation of a novel prognostic scoring model for ischemic colitis.

PURPOSE: This study was conducted to identify prognostic factors affecting the course of ischemic colitis and to develop a prognostic scoring model. METHODS: We analyzed medical records of consecutive patients with ischemic colitis treated between October 2002 and September 2008 at Severance Hospital, Seoul, Republic of Korea. Patients were excluded if results of endoscopy were unavailable. Patients were classified as having severe ischemic colitis on the basis of outcome (improvement delayed for more than 2 weeks, complications requiring surgery, or death). Univariate analyses and multivariate logistic regression analyses with backward stepwise selection were used to identify clinical, endoscopic, and laboratory variables associated with severe ischemic colitis. A novel prognostic scoring model was derived from the data, with probability of severe ischemic colitis and risk index determined for 8 risk groups based on independent risk factors identified by multivariate analyses. Predictive power was tested by means of 10-fold cross-validation, with area under the receiver operating characteristic curve representing discrimination accuracy. RESULTS: Analyzable data were available for 153 of 173 consecutive patients. Ischemic colitis was classified as severe in 20 patients. Multivariate analyses showed the following significant independent predictors of severe ischemic colitis: tachycardia (adjusted odds ratio = 4.6; 95% CI, 1.4-14.7), shock within 24 hours after admission (adjusted odds ratio = 6.5; 95% CI, 2.0-21.2), and endoscopic evidence of ulceration (adjusted odds ratio = 9.9; 95% CI, 2.0-48.8). Probability of severe ischemic colitis and risk index were 74 times higher for patients with all 3 risk factors (group 8) than for patients with none (group 1). Internal validation showed the area under the receiver operating characteristic curve to be 0.91 (95% confidence interval, 0.86-0.96). CONCLUSIONS: Endoscopic findings and instability of vital signs were associated with the disease course of ischemic colitis. A novel scoring model based on presence of tachycardia, shock within 24 hours after admission, and endoscopic evidence of ulceration provides a method of assessing patient prognosis and should be further validated.

A case of embryonal sarcoma of the liver mimicking a hydatid cyst in an adult.

An undifferentiated (embryonal) liver sarcoma (ULS) originates from a primitive mesenchymal cell, with a predilection for childhood and very rare occurrence in adults. We report a case of a ULS that was incidentally found in a 53-year-old female. Our case was initially interpreted as a large hydatid cyst, which was later suspected to be a neoplastic lesion because its size was increasing and a solid portion was newly detected after shrinkage of the cyst following drainage. The patient underwent successful right hepatic lobectomy with complete resection, and is currently disease-free without adjuvant therapy. Although it is difficult to diagnose a hepatic cyst as a ULS due to its rare occurrence in adulthood and lack of specific findings, its possibility should be considered, especially when its size is increasing, because early diagnosis and curative resection are necessary for a favorable outcome.

[Aplastic anemia with trisomy 8 and trisomy 9 in intestinal behcets disease].

Behcets disease is a multisystemic inflammatory disease characterized with recurrent oral ulcer, genital ulcer, and multiple organ involvement. Aplastic anemia is one of the rarest complications of Behcets disease. There were only several reports about Behcets disease associated myelodysplatic syndrome worldwide. Moreover, aplastic anemia in intestinal Behcets disease was rarely reported. Here, we present a case of aplastic anemia with trisomy 8 and trisomy 9 in intestinal Behcets disease and a review of the literatures. To the authors knowledge, this is the first case ever reported in Korea.

Effect of vancomycin plus rifampicin in the treatment of nosocomial methicillin-resistant Staphylococcus aureus pneumonia.

OBJECTIVE: To investigate whether adding rifampicin to vancomycin could cure more patients with nosocomial methicillin-resistant Staphylococcus aureus pneumonia compared with vancomycin-only. DESIGN: Prospective randomized open-label study. SETTING: Medical intensive care unit in Seoul, Korea. PATIENTS: Ninety-three of 183 patients with Gram-positive nosocomial pneumonia. INTERVENTIONS: The enrolled patients with subsequently documented methicillin-resistant Staphylococcus aureus pneumonia (modified intention-to-treat population) were treated with vancomycin (1 g intravenous every 12 hrs) plus rifampicin (300 mg twice daily by mouth) (n = 41) or with vancomycin-only (n = 42). The intended treatment (at least 5 days) was completed in 30 patients in the vancomycin plus rifampicin group and 34 patients in the vancomycin-only group (per protocol population). MEASUREMENTS AND MAIN RESULTS: The primary outcome was the clinical cure rate on day 14 of treatment. The secondary outcomes were intensive care unit mortality on days 28 and 60, and microbiological eradication on day 14. The clinical cure rate in the modified intention-to-treat population was 53.7% (22 of 41) in the vancomycin plus rifampicin group, and 31.0% (13 of 42) in the vancomycin-only group (p = .047), and the respective rates in the per protocol population were 63.3% (19 of 30) and 38.2% (13 of 34) (p = .079). The respective mortality rates were nine (22.0%) of 41 and 16 (38.1%) of 42 on day 28 (p = .151), and 11 (26.8%) of 41 and 21 (50.0%) of 42 on day 60 (p = .042). The microbiological eradication rate did not differ between groups (p = .472). CONCLUSIONS: Vancomycin plus rifampicin seems to be more effective than vancomycin alone in the treatment of nosocomial methicillin-resistant Staphylococcus aureus pneumonia.

Tension pneumopericardium after removal of pericardiocentesis drainage catheter.

This image showed tension pneumopericardium caused by removing the pericardiocentesis catheter, which was inserted to drain malignant pericardial effusion. Tension pneumopericardium is a rare and potentially fatal event. Mortality from tension pneumopericardium can be as high as 50%. Therefore, it is important to suspect and detect early, if the patient complained of dyspnea after removing the pericardiocentesis drainage catheter.