Short-term psychosocial outcomes of adding a non-contrast abdominal computed tomography (CT) scan to the thoracic CT within lung cancer screening.

OBJECTIVES: To evaluate psychological, social, and financial outcomes amongst individuals undergoing a non-contrast abdominal computed tomography (CT) scan to screen for kidney cancer and other abdominal malignancies alongside the thoracic CT within lung cancer screening. SUBJECTS AND METHODS: The Yorkshire Kidney Screening Trial (YKST) is a feasibility study of adding a non-contrast abdominal CT scan to the thoracic CT within lung cancer screening. A total of 500 participants within the YKST, comprising all who had an abnormal CT scan and a random sample of one-third of those with a normal scan between 14/03/2022 and 24/08/2022 were sent a questionnaire at 3 and 6 months. Outcomes included the Psychological Consequences Questionnaire (PCQ), the short-form of the Spielberger State-Trait Anxiety Inventory, and the EuroQoL five Dimensions five Levels scale (EQ-5D-5L). Data were analysed using regression adjusting for participant age, sex, socioeconomic status, education, baseline quality of life (EQ-5D-5L), and ethnicity. RESULTS: A total of 380 (76%) participants returned questionnaires at 3 months and 328 (66%) at 6 months. There was no difference in any outcomes between participants with a normal scan and those with abnormal scans requiring no further action. Individuals requiring initial further investigations or referral had higher scores on the negative PCQ than those with normal scans at 3 months (standardised mean difference 0.28 sd, 95% confidence interval 0.01-0.54; P = 0.044). The difference was greater in those with anxiety or depression at baseline. No differences were seen at 6 months. CONCLUSION: Screening for kidney cancer and other abdominal malignancies using abdominal CT alongside the thoracic CT within lung cancer screening is unlikely to cause significant lasting psychosocial or financial harm to participants with incidental findings.

Splenic abscess and infective endocarditis.

OBJECTIVE: To determine the background, bacteriological, clinical and radiological findings, associated lesions, treatment and outcome of splenic abscesses (SAs) in infective endocarditis (IE). METHODS: Retrospective study (2005-2021) of 474 patients with definite IE. The diagnosis of SA was made in 36 (7.6%) patients (31, 86.1%, males, mean age = 51.3) on abdominal CT. RESULTS: The main implicated organisms were Streptococcus spp (36.1%), Enterococcus faecalis (27.7%), Staphyloccus spp (19.4%). Rare agents were present in 10 patients (27.8%). Pre-existing conditions included a prosthetic valve (19.4%), previous IE (13.9%), intravenous drug use (8.4%), diabetes (25%) alcohol abuse (13.9%), liver disease (5.5%). Vegetations ≥ 15 mm were present in 36.1%. Common presentations were abdominal pain (19.4%) and left-sided pleural effusion (16.5%). SA were more often small (50%; 7 multiple) than large (36.1%; 1 multiple) or microabscesses (13.9%, 3 multiple). Associated complications were extrasplenic abscesses (brain, 11.1%; lung, 5.5%; liver, 2.8%), infectious aneurysms (16.7%: 3 intracranial, 1 splenic, 1 hepatic, 1 popliteal), emboli (brain, 52.8%; spleen, 44.4%, 5 evolving to SA; kidney, 22.2%; aorta, 2.8%), osteoarticular infections (25%). Twenty-eight (77.8%) patients only received antimicrobials, 7 (19.4%) underwent splenectomy, after cardiac surgery in 5. One had percutaneous drainage. The outcome was uneventful (follow-up 3 months-14 years; mean: 17.2 months). CONCLUSION: In SA-IE patients, the prevalence of vegetation size, Enterococcus faecalis, rare germs, diabetes, osteo-arthritic involvement and cancer was higher than in non-SA patients. Some SAs developed from splenic infarcts. IE-patients with evidence of splenic emboli should be evaluated for a possible abcedation. Cardiac surgery before splenectomy was safe.

The diagnostic accuracy of triphasic abdominal CT in detecting esophageal varices.

BACKGROUND: In Tanzania, triphasic abdominal Computed Tomography (CT) is a more accessible and non-invasive alternative for diagnosing esophageal varices, though its accuracy has not been thoroughly evaluated, therefore this study aimed to determine the diagnostic accuracy of triphasic abdominal CT in detecting esophageal varices using esophagogastroduodenoscopy (OGD) as the gold standard among patients with upper gastrointestinal bleeding at Muhimbili National Hospital (MNH). METHODS: This cross-sectional study was conducted at MNH from January 2021 to May 2023. We sampled upper gastrointestinal bleeding patients who underwent both OGD and triphasic abdominal CT using non-probability consecutive sampling. The sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy of triphasic abdominal CT were assessed against OGD findings. RESULTS: In a study of 200 participants, esophageal varices were detected in 54% by OGD and 53.5% by CT. We observed 105 true positives, 2 false positives, 90 true negatives, and 3 false negatives. Triphasic abdominal CT demonstrated a sensitivity of 97.2%, specificity of 97.8%, PPV of 98.1%, NPV of 96.8%, and an accuracy of 97.5%. Extraluminal findings included portal venous thrombosis in (22%), splenic collateral (51.5%), ascites (32%), hepatocellular carcinoma (13%), and periportal fibrosis (32%). CONCLUSION: Triphasic abdominal Computed Tomography can be used as a reliable and non-invasive alternative modality for diagnosing and screening esophageal varices in resource-limited settings.

A deep learning-powered diagnostic model for acute pancreatitis.

BACKGROUND: Acute pancreatitis is one of the most common diseases requiring emergency surgery. Rapid and accurate recognition of acute pancreatitis can help improve clinical outcomes. This study aimed to develop a deep learning-powered diagnostic model for acute pancreatitis. MATERIALS AND METHODS: In this investigation, we enrolled a cohort of 190 patients with acute pancreatitis who were admitted to Sichuan Provincial People's Hospital between January 2020 and December 2021. Abdominal computed tomography (CT) scans were obtained from both patients with acute pancreatitis and healthy individuals. Our model was constructed using two modules: (1) the acute pancreatitis classifier module; (2) the pancreatitis lesion segmentation module. Each model's performance was assessed based on precision, recall rate, F1-score, Area Under the Curve (AUC), loss rate, frequency-weighted accuracy (fwavacc), and Mean Intersection over Union (MIOU). RESULTS: Upon admission, significant variations were observed between patients with mild and severe acute pancreatitis in inflammatory indexes, liver, and kidney function indicators, as well as coagulation parameters. The acute pancreatitis classifier module exhibited commendable diagnostic efficacy, showing an impressive AUC of 0.993 (95%CI: 0.978-0.999) in the test set (comprising healthy examination patients vs. those with acute pancreatitis, P < 0.001) and an AUC of 0.850 (95%CI: 0.790-0.898) in the external validation set (healthy examination patients vs. patients with acute pancreatitis, P < 0.001). Furthermore, the acute pancreatitis lesion segmentation module demonstrated exceptional performance in the validation set. For pancreas segmentation, peripancreatic inflammatory exudation, peripancreatic effusion, and peripancreatic abscess necrosis, the MIOU values were 86.02 (84.52, 87.20), 61.81 (56.25, 64.83), 57.73 (49.90, 68.23), and 66.36 (55.08, 72.12), respectively. These findings underscore the robustness and reliability of the developed models in accurately characterizing and assessing acute pancreatitis. CONCLUSION: The diagnostic model for acute pancreatitis, driven by deep learning, exhibits excellent efficacy in accurately evaluating the severity of the condition. TRIAL REGISTRATION: This is a retrospective study.

Comparative study of abdominal CT enhancement in overweight and obese patients based on different scanning modes combined with different contrast medium concentrations.

PURPOSE: To compare image quality, iodine intake, and radiation dose in overweight and obese patients undergoing abdominal computed tomography (CT) enhancement using different scanning modes and contrast medium. METHODS: Ninety overweight and obese patients (25 kg/m2≤body mass index (BMI)< 30 kg/m2 and BMI≥30 kg/m2) who underwent abdominal CT-enhanced examinations were randomized into three groups (A, B, and C) of 30 each and scanned using gemstone spectral imaging (GSI) +320 mgI/ml, 100 kVp + 370 mgI/ml, and 120 kVp + 370 mgI/ml, respectively. Reconstruct monochromatic energy images of group A at 50-70 keV (5 keV interval). The iodine intake and radiation dose of each group were recorded and calculated. The CT values, contrast-to-noise ratios (CNRs), and subjective scores of each subgroup image in group A versus images in groups B and C were by using one-way analysis of variance or Kruskal-Wallis H test, and the optimal keV of group A was selected. RESULTS: The dual-phase CT values and CNRs of each part in group A were higher than or similar to those in groups B and C at 50-60 keV, and similar to or lower than those in groups B and C at 65 keV and 70 keV. The subjective scores of the dual-phase images in group A were lower than those of groups B and C at 50 keV and 55 keV, whereas no significant difference was seen at 60-70 keV. Compared to groups B and C, the iodine intake in group A decreased by 12.5% and 13.3%, respectively. The effective doses in groups A and B were 24.7% and 25.8% lower than those in group C, respectively. CONCLUSION: GSI +320 mgI/ml for abdominal CT-enhanced in overweight patients satisfies image quality while reducing iodine intake and radiation dose, and the optimal keV was 60 keV.

Hepatic vessels segmentation using deep learning and preprocessing enhancement.

PURPOSE: Liver hepatic vessels segmentation is a crucial step for the diagnosis process in patients with hepatic diseases. Segmentation of liver vessels helps to study the liver internal segmental anatomy that helps in the preoperative planning of surgical treatment. METHODS: Recently, the convolutional neural networks (CNN) have been proved to be efficient for the task of medical image segmentation. The paper proposes an automatic deep learning-based system for liver hepatic vessels segmentation of Computed Tomography (CT) datasets from different sources. The proposed work focuses on the combination of different steps; it starts by a preprocessing step to improve the vessels appearance within the liver region of interest in the CT scans. Coherence enhancing diffusion filtering (CED) and vesselness filtering methods are used to improve vessels contrast and intensity homogeneity. The proposed U-net based network architecture is implemented with modified residual block to include concatenation skip connection. The effect of enhancement using filtering step was studied. Also, the effect of data mismatch used in training and validation is studied. RESULTS: The proposed method is evaluated using many CT datasets. Dice similarity coefficient (DSC) is used to evaluate the method. The average DSC score achieved a score 79%. CONCLUSIONS: The proposed approach succeeded to segment liver vasculature from the liver envelope accurately, which makes it as potential tool for clinical preoperative planning.

Effective dose and radiation risk under 640-slice abdominal computed tomography examination without contrast medium injection.

BACKGROUND: Medical imaging plays a crucial role in modern medicine. In order to provide fast and accurate medical diagnosis, computed tomography (CT) is a commonly used tool in radiological examinations, and 640-slice CT is the most advanced CT imaging modality. OBJECTIVE: To evaluate the radiation dose and the risk under 640-slice abdominal CT examination. METHODS: Examinations were performed using a 640-slice CT scanner on an Alderson-Rando anthropomorphic phantom. The used scanning acquisition parameters were the same as those used on abdominal examination without contrast medium injection in clinical practice. To measure the absorbed doses, optically stimulated luminescence dosimeters (OSLDs) were put into liver, stomach, bladder, gonads, colon, small intestine, bone marrow, and skin. RESULTS: According to the 1990 Recommendations of the International Commission on Radiological Protection (ICRP Publication 60), the calculated effective doses received from this examination were 0.90 mSv in males and 0.89 mSv in females. According to the 2007 Recommendations of the International Commission on Radiological Protection (ICRP Publication 103), the calculated effective dose received from this examination was 0.83 mSv in both sexes. CONCLUSIONS: Radiation doses obtained from the abdominal 640-slice CT examination are lower than the yearly cumulative doses received from natural radiation, revealing there is no deterministic effect and radiation risk is relatively low; therefore, this CT examination is considered safe.

Clinical added value of MRI to CT in patients scheduled for local therapy of colorectal liver metastases (CAMINO): study protocol for an international multicentre prospective diagnostic accuracy study.

BACKGROUND: Abdominal computed tomography (CT) is the standard imaging method for patients with suspected colorectal liver metastases (CRLM) in the diagnostic workup for surgery or thermal ablation. Diffusion-weighted and gadoxetic-acid-enhanced magnetic resonance imaging (MRI) of the liver is increasingly used to improve the detection rate and characterization of liver lesions. MRI is superior in detection and characterization of CRLM as compared to CT. However, it is unknown how MRI actually impacts patient management. The primary aim of the CAMINO study is to evaluate whether MRI has sufficient clinical added value to be routinely added to CT in the staging of CRLM. The secondary objective is to identify subgroups who benefit the most from additional MRI. METHODS: In this international multicentre prospective incremental diagnostic accuracy study, 298 patients with primary or recurrent CRLM scheduled for curative liver resection or thermal ablation based on CT staging will be enrolled from 17 centres across the Netherlands, Belgium, Norway, and Italy. All study participants will undergo CT and diffusion-weighted and gadoxetic-acid enhanced MRI prior to local therapy. The local multidisciplinary team will provide two local therapy plans: first, based on CT-staging and second, based on both CT and MRI. The primary outcome measure is the proportion of clinically significant CRLM (CS-CRLM) detected by MRI not visible on CT. CS-CRLM are defined as liver lesions leading to a change in local therapeutical management. If MRI detects new CRLM in segments which would have been resected in the original operative plan, these are not considered CS-CRLM. It is hypothesized that MRI will lead to the detection of CS-CRLM in ≥10% of patients which is considered the minimal clinically important difference. Furthermore, a prediction model will be developed using multivariable logistic regression modelling to evaluate the predictive value of patient, tumor and procedural variables on finding CS-CRLM on MRI. DISCUSSION: The CAMINO study will clarify the clinical added value of MRI to CT in patients with CRLM scheduled for local therapy. This study will provide the evidence required for the implementation of additional MRI in the routine work-up of patients with primary and recurrent CRLM for local therapy. TRIAL REGISTRATION: The CAMINO study was registered in the Netherlands National Trial Register under number NL8039 on September 20th 2019.

Effect of a split-flow physician in triage model on abdominal CT ordering rate and yield.

OBJECTIVE: The objective of this study was to compare the rate and clinical yield of computed tomography (CT) imaging between patients presenting with abdominal pain initially seen by a physician in triage (PIT) versus those seen only by physicians working in the main emergency department (ED). METHODS: A retrospective study was conducted of all self-arrivals >18 years old presenting to a single ED with abdominal pain. Nine-hundred patients were randomly selected from both the PIT and traditional patient flow groups and rates and yields of CT imaging were compared, both alone and in a model controlling for potential confounders. Predetermined criteria for CT significance included need for admission, consult, or targeted medications. RESULTS: The overall rate of CT imaging (unadjusted) did not differ between the PIT and traditional groups, 48.7% (95% CI 45.4-51.9) vs. 45.1% (95% CI 41.8-48.4), respectively (p = .13). The CT yield for patients seen in in the PIT group was also similar to that of the traditional group: 49.1% (95% CI 44.4-53.8) vs. 50.5% (95% CI 45.6-55.4) (p = .68). In the logistic regression model, when controlling for age, gender, ESI-acuity, race and insurance payor, PIT vs. traditional was not a predictor of CT ordering (OR 1.14, 95% CI 0.94-1.38). CONCLUSIONS: For patients with abdominal pain, we found no significant differences in rates of CT ordering or CT yield for patients seen in a PIT vs. traditional models, suggesting the increased efficiencies offered by PIT models do not come at the cost of increased or decreased imaging utilization.

Challenge in diagnosis of late onset necrotizing enterocolitis in a term infant: a case report.

BACKGROUND: Necrotizing enterocolitis (NEC) is a common devastating inflammatory gastrointestinal disease and frequently occurs in premature infants. Here, we reported a case of late-onset NEC in a term neonate with good outcome after surgery for long-term follow-up. CASE PRESENTATION: Ten-week-old male came to emergency unit due to prolonged diarrhea and abdominal distention. He was born at gestational age of 40 weeks with birth weight and Apgar score of 2800 g and 7/8, respectively. He had no history of formula feeding. Two weeks before admitted to the hospital, the patient had frequent diarrhea with fever. He was found lethargic with abdominal distention, absence of bowel sounds and abdominal tenderness. Plain abdominal x-ray and CT scan showed gastric and intestinal dilatation and gasless colon, suggesting a small bowel obstruction, and bowel wall thickening indicating peritonitis, without any free subdiaphragmatic air (pneumoperitoneum). Moreover, the patient did not have a congenital heart disease. While in intensive medical treatment, he showed a continuous clinical deterioration. All findings were suggestive of intestinal inflammation with clinical deterioration, and we decided to perform an emergency exploratory laparotomy and found an ischemia along the jejunoileal with a perforation at 25 cm above the ileocecal valve. Subsequently, we performed a double-barrel ileostomy through a separate incision from the laparotomy. Histopathological findings confirmed the diagnosis of NEC. We closed the stoma at postoperative day 43. The patient was discharged uneventfully a month after stoma closure. CONCLUSION: Abdominal CT scan might be useful to establish an early recognition of late-onset NEC; thus, immediate surgical intervention might be performed to decrease its morbidity and mortality. Moreover, late-onset NEC in term neonates might occur without any risk factors or significant co-morbidities.

Twelve tips for interpreting abdominal CT scans.

BACKGROUND: Abdominal computerised tomography (CT) scans are a crucial tool in the diagnosis and management of the acute abdomen. Currently, medical students are not widely and extensively trained in the interpretation of abdominal scans. AIM: We aim to provide advice about interpreting abdominal CT scans. METHODS: We used the critical reflection of our experiences, both in clinical practice and in teaching, alongside advice from the literature to develop these tips. RESULTS: Twelve tips following the '4As, 3Bs, 2Cs and 1D' approach are presented to assist doctors and medical students with interpreting abdominal CT scans. CONCLUSION: The early identification of pathology on CT scans has been demonstrated to improve patient outcomes in certain cases, while a formal radiologist's report is awaited. Following a systematic approach, such as the one we presented here, may aid trainees in looking at abdominal CT scans.

An Unsupervised Learning-Based Multi-Organ Registration Method for 3D Abdominal CT Images.

Medical image registration is an essential technique to achieve spatial consistency geometric positions of different medical images obtained from single- or multi-sensor, such as computed tomography (CT), magnetic resonance (MR), and ultrasound (US) images. In this paper, an improved unsupervised learning-based framework is proposed for multi-organ registration on 3D abdominal CT images. First, the explored coarse-to-fine recursive cascaded network (RCN) modules are embedded into a basic U-net framework to achieve more accurate multi-organ registration results from 3D abdominal CT images. Then, a topology-preserving loss is added in the total loss function to avoid a distortion of the predicted transformation field. Four public databases are selected to validate the registration performances of the proposed method. The experimental results show that the proposed method is superior to some existing traditional and deep learning-based methods and is promising to meet the real-time and high-precision clinical registration requirements of 3D abdominal CT images.

Reported and Unreported Potentially Important Incidental Findings in Urgent Nonenhanced Abdominal CT for Renal Colic.

OBJECTIVE: The aim of the study was to retrospectively evaluate the prevalence of reported and unreported potentially important incidental findings (PIFs) in consecutive nonenhanced abdominal CTs performed specifically for renal colic in the urgent setting. METHODS: One radiologist, blinded to the finalized report, retrospectively re-evaluated nonenhanced abdominal CTs performed from January to December 2017 on adult patients from the emergency department with the specific request of urgent evaluation for renal colic, searching for PIFs. RESULTS: The CTs of 312 patients were included in the study. Thirty-eight findings were reported in 38 different CTs, whereas the re-evaluation added 47 unreported findings in 47 different CTs, adding to total of 85 findings (27%). The difference in the proportion of reported and unreported PIFs between the original report and re-evaluation was significant (p < 0.001). No significant difference was found between the age of patients with and without reported findings. The proportion of potentially important findings did not vary significantly among the 3 shifts in the original report and in re-evaluation. The most frequent findings, both reported and unreported, were pleural effusion, lymphadenopathies, and liver nodules. CONCLUSIONS: Potentially important additional findings are frequently present in urgent nonenhanced abdominal CTs performed for renal colic, and many are not described in the finalized reports. Radiologists should take care not to underreport PIFs even in the urgent setting because of the possible consequences on the patient's health and in order to avoid legal issues, while at the same time satisfying the need for timely and efficient reporting.

A feasibility study of realizing low-dose abdominal CT using deep learning image reconstruction algorithm.

OBJECTIVES: To explore the feasibility of achieving diagnostic images in low-dose abdominal CT using a Deep Learning Image Reconstruction (DLIR) algorithm. METHODS: Prospectively enrolled 47 patients requiring contrast-enhanced abdominal CT scans. The late-arterial phase scan was added and acquired using lower-dose mode (tube current range, 175-545 mA; 80 kVp for patients with BMI ≤24 kg/m2 and 100 kVp for patients with BMI > 24 kg/m2) and reconstructed with DLIR at medium setting (DLIR-M) and high setting (DLIR-H), ASIR-V at 0% (FBP), 40% and 80% strength. Both the quantitative measurement and qualitative analysis of the five types of reconstruction methods were compared. In addition, radiation dose and image quality between the early-arterial phase ASIR-V images using standard-dose and the late-arterial phase DLIR images using low-dose were compared. RESULTS: For the late-arterial phase, all five reconstructions had similar CT value (P > 0.05). DLIR-H, DLIR-M and ASIR-V80% images significantly reduced the image noise and improved the image contrast noise ratio, compared with the standard ASIR-V40% images (P < 0.05). ASIR-V80% images had undesirable image characteristics with obvious "waxy" artifacts, while DLIR-H images maintained high spatial resolution and had the highest subjective image quality. Compared with the early-arterial scans, the late-arterial phase scans significantly reduced the radiation dose (P < 0.05), while the DLIR-H images exhibited lower image noise and good display of the specific image details of lesions. CONCLUSIONS: DLIR algorithm improves image quality under low-dose scan condition and may be used to reduce the radiation dose without adversely affecting the image quality.

Lung Base Findings of Coronavirus Disease (COVID-19) on Abdominal CT in Patients With Predominant Gastrointestinal Symptoms.

OBJECTIVE. This series of patients presented to the emergency department (ED) with abdominal pain, without the respiratory symptoms typical of coronavirus disease (COVID-19), and the abdominal radiologist was the first to suggest COVID-19 infection because of findings in the lung bases on CT of the abdomen. CONCLUSION. COVID-19 infection can present primarily with abdominal symptoms, and the abdominal radiologist must suggest the diagnosis when evaluating the lung bases for typical findings.

Positive Oral Contrast Material for Abdominal CT: Current Clinical Indications and Areas of Controversy.

OBJECTIVE. The use of positive oral contrast material for abdominal CT is a frequent protocol issue. Confusion abounds regarding its use, and practice patterns often appear arbitrary. Turning to the existing literature for answers is unrewarding, because most studies are underpowered or not designed to address key endpoints. Even worse, many decisions are now being driven by nonradiologists for throughput gains rather than patient-specific considerations. Herein, the current indications for positive oral contrast material are discussed, including areas of controversy. CONCLUSION. As radiologists, we owe it to our patients to drive the appropriate use of positive oral contrast material. At the very least, we should not allow nonradiologists to restrict its use solely on the basis of throughput concerns; rather, we should allow considerations of image quality and diagnostic confidence to enter into the decision process. Based on differences in prior training and practice patterns, some radiologists will prefer to limit the use of positive oral contrast material more than others. However, for those who believe (as I do) that it can genuinely increase diagnostic confidence and can sometimes (rather unpredictably) make a major impact on diagnosis, it behooves us to keep fighting for its use.

Unexpected Findings of Coronavirus Disease (COVID-19) at the Lung Bases on Abdominopelvic CT.

OBJECTIVE. The purpose of this study is to report unanticipated lung base findings on abdominal CT in 23 patients concerning for coronavirus disease (COVID-19). In these patients, who were not previously suspected of having COVID-19, abdominal pain was the most common indication for CT (n = 19), and 11 patients had no extrapulmonary findings. Seventeen patients underwent polymerase chain reaction testing, which returned positive results for all 17. CONCLUSION. Unsuspected coronavirus disease may be strongly suggested on the basis of lung findings on abdominopelvic CT.

Physicians' understanding of CT probabilities in ED patients with acute abdominal pain.

OBJECTIVE: Computerized tomography (CT) is often employed to diagnose or rule out certain suspected abdominal pathologies. The aim of this study is to compare emergency physicians' estimated post-test disease probabilities to the probabilities obtained for similar diagnostic tests as reported in the literature. METHODS: Physicians were asked to estimate pre and posttest probabilities before and after CT scan results in patients with nontraumatic abdominal and pelvic pain. The actual post-test probability was calculated using published likelihood ratios and compared to physician judgment. RESULTS: 210 patient encounters were included. In the negative CT group, physicians' median pre-test probability was 40% with a post-test probability of 0%, while the actual post-test probability is 4.2% (p<0.001). Physicians' median pre-test probability for a positive CT was 70% with a post-test probability of 100%, while the actual post-test probability is 98% (p<0.001). The diverticulitis subgroup had no significant differences between physician and actual post-test probabilities. The post-op abscess subgroup had significant differences in post-test probabilities in both the negative CT (30% difference, p=0.028) and positive CT subgroups (-37% difference, p=0.003). CONCLUSIONS: When applying the probability theory of disease, physicians tend to overestimate the power of CT scanning. The difference in physician and actual post-test probabilities may be small or not clinically significant in diseases with good positive and negative likelihood ratios such as in diverticulitis; however, this difference may be large and clinically significant in diseases with poor likelihood ratios such as in post-op abscess.

A new technique for the diagnosis of acute appendicitis: abdominal CT with compression to the right lower quadrant.

OBJECTIVE: To determine the diagnostic accuracy of abdominal CT with compression to the right lower quadrant (RLQ) in adults with acute appendicitis. METHODS: 168 patients (age range, 18-78 years) were included who underwent contrast-enhanced CT for suspected appendicitis performed either using compression to the RLQ (n = 71) or a standard protocol (n = 97). Outer diameter of the appendix, appendiceal wall thickening, luminal content and associated findings were evaluated in each patient. Kruskal-Wallis, Fisher's and Pearson's chi-squared tests were used for statistical analysis. RESULTS: There was no significant difference in the mean outer diameter (MOD) between compression CT scans (10.6 ± 1.9 mm) and standard protocol (11.2 ± 2.3 mm) in patients with acute appendicitis (P = 1). MOD was significantly lower in the compression group (5.2 ± 0.8 mm) compared to the standard protocol (6.5 ± 1.1 mm) (P < 0.01) in patients without appendicitis. A cut-off value of 6.75 mm for the outer diameter of the appendix was found to be 100% sensitive in the diagnosis of acute appendicitis for both groups. The specificity was higher for compression CT technique (67.7 vs. 94.9%). CONCLUSION: Normal appendix diameter was significantly smaller in the compression-CT group compared to standard-CT group, increasing diagnostic accuracy of abdominal compression CT. KEY POINTS: • Normal appendix diameter is significantly smaller in compression CT. • Compression could force contrast material to flow through the appendiceal lumen. • Compression CT may be a CT counterpart of graded compression US.

Pattern of extragastric recurrence and the role of abdominal computed tomography in surveillance after endoscopic resection of early gastric cancer: Korean experiences.

BACKGROUND: Although extragastric recurrence after endoscopic resection of early gastric cancer is rare, it is important because of its potentially fatal outcomes. We investigated the patterns of extragastric recurrence after endoscopic resection and evaluated the role of abdominal computed tomography in surveillance. METHODS: Between July 1994 and June 2014, 4915 patients underwent endoscopic resection of early gastric cancer. Because of follow-up periods of less than 6 months and consecutive surgery within 1 year, 810 patients were excluded. Thus, 4105 patients were retrospectively reviewed. RESULTS: The median follow-up period was 37 months (interquartile range 20-59.6 months). The overall incidence of extragastric recurrence was 0.37% (n = 15). In patients who underwent curative resection, the incidence was 0.14% (n = 5). There were three recurrences in the absolute indication group, six in the expanded indication group, and six in the beyond expanded indication group. The median time to extragastric recurrence was 17 months (interquartile range 16.5-43.2 months). Of the 15 extragastric recurrences, 11 were in the regional lymph nodes and 4 were in the liver, adrenal gland, and peritoneum. Sixty percent (9/15) of the extragastric recurrences occurred without intragastric lesions. Eleven recurrences were detected by abdominal computed tomography, and eight patients underwent curative surgery. CONCLUSIONS: After endoscopic resection of early gastric cancer, regional lymph node recurrence is the predominant extragastric recurrence pattern, which can be detected via abdominal computed tomography and cured by rescue surgery. Abdominal computed tomography should be considered as a surveillance method, especially in patients with an expanded indication.