Artificial intelligence as a diagnostic aid in cross-sectional radiological imaging of surgical pathology in the abdominopelvic cavity: a systematic review

OBJECTIVES

There is emerging use of artificial intelligence (AI) models to aid diagnostic imaging. This review examined and critically appraised the application of AI models to identify surgical pathology from radiological images of the abdominopelvic cavity, to identify current limitations and inform future research.

DESIGN

Systematic review.

DATA SOURCES

Systematic database searches (Medline, EMBASE, Cochrane Central Register of Controlled Trials) were performed. Date limitations (January 2012 to July 2021) were applied.

ELIGIBILITY CRITERIA

Primary research studies were considered for eligibility using the PIRT (participants, index test(s), reference standard and target condition) framework. Only publications in the English language were eligible for inclusion in the review.

DATA EXTRACTION AND SYNTHESIS

Study characteristics, descriptions of AI models and outcomes assessing diagnostic performance were extracted by independent reviewers. A narrative synthesis was performed in accordance with the Synthesis Without Meta-analysis guidelines. Risk of bias was assessed (Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2)).

RESULTS

Fifteen retrospective studies were included. Studies were diverse in surgical specialty, the intention of the AI applications and the models used. AI training and test sets comprised a median of 130 (range: 5-2440) and 37 (range: 10-1045) patients, respectively. Diagnostic performance of models varied (range: 70%-95% sensitivity, 53%-98% specificity). Only four studies compared the AI model with human performance. Reporting of studies was unstandardised and often lacking in detail. Most studies (n=14) were judged as having overall high risk of bias with concerns regarding applicability.

CONCLUSIONS

AI application in this field is diverse. Adherence to reporting guidelines is warranted. With finite healthcare resources, future endeavours may benefit from targeting areas where radiological expertise is in high demand to provide greater efficiency in clinical care. Translation to clinical practice and adoption of a multidisciplinary approach should be of high priority.

PROSPERO REGISTRATION NUMBER

CRD42021237249.

Artificial intelligence as a diagnostic aid in cross-sectional radiological imaging of the abdominopelvic cavity: a protocol for a systematic review

INTRODUCTION

The application of artificial intelligence (AI) technologies as a diagnostic aid in healthcare is increasing. Benefits include applications to improve health systems, such as rapid and accurate interpretation of medical images. This may improve the performance of diagnostic, prognostic and management decisions. While a large amount of work has been undertaken discussing the role of AI little is understood regarding the performance of such applications in the clinical setting. This systematic review aims to critically appraise the diagnostic performance of AI algorithms to identify disease from cross-sectional radiological images of the abdominopelvic cavity, to identify current limitations and inform future research.

METHODS AND ANALYSIS

A systematic search will be conducted on Medline, EMBASE and the Cochrane Central Register of Controlled Trials to identify relevant studies. Primary studies where AI-based technologies have been used as a diagnostic aid in cross-sectional radiological images of the abdominopelvic cavity will be included. Diagnostic accuracy of AI models, including reported sensitivity, specificity, predictive values, likelihood ratios and the area under the receiver operating characteristic curve will be examined and compared with standard practice. Risk of bias of included studies will be assessed using the QUADAS-2 tool. Findings will be reported according to the Synthesis Without Meta-analysis guidelines.

ETHICS AND DISSEMINATION

No ethical approval is required as primary data will not be collected. The results will inform further research studies in this field. Findings will be disseminated at relevant conferences, on social media and published in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42021237249.

Childhood energy intake is associated with nonalcoholic fatty liver disease in adolescents

BACKGROUND

Greater adiposity is an important risk factor for nonalcoholic fatty liver disease (NAFLD). Thus, it is likely that dietary intake is involved in the development of the disease. Prospective studies assessing the relation between childhood dietary intake and risk of NAFLD are lacking.

OBJECTIVE

This study was designed to explore associations between energy, carbohydrate, sugar, starch, protein, monounsaturated fat, polyunsaturated fat, saturated fat, and total fat intake by youth at ages 3, 7, and 13 y and subsequent (mean age: 17.8 y) ultrasound scan (USS)-measured liver fat and stiffness and serum alanine aminotransferase, aspartate aminotransferase, and γ-glutamyltransferase. We assessed whether observed associations were mediated through fat mass at the time of outcome assessment.

METHODS

Participants were from the Avon Longitudinal Study of Parents and Children. Trajectories of energy and macronutrient intake from ages 3-13 y were obtained with linear-spline multilevel models. Linear and logistic regression models examined whether energy intake and absolute and energy-adjusted macronutrient intake at ages 3, 7, and 13 y were associated with liver outcomes.

RESULTS

Energy intake at all ages was positively associated with liver outcomes; for example, the odds of having a USS-measured liver fat per 100 kcal increase in energy intake at age 3 y were 1.79 (95% CI: 1.14, 2.79). Associations between absolute macronutrient intake and liver outcomes were inconsistent and attenuated to the null after adjustment for total energy intake. The majority of associations attenuated to the null after adjustment for fat mass at the time liver outcomes were assessed.

CONCLUSION

Higher childhood and early adolescent energy intake is associated with greater NAFLD risk, and the macronutrients from which energy intake is derived are less important. These associations appear to be mediated, at least in part, by fat mass at the time of outcome assessment.

Pancreatic volume is reduced in adult patients with recently diagnosed type 1 diabetes

CONTEXT

Pancreatic atrophy is common in longstanding type 1 diabetes, but there are limited data concerning pancreas size at diagnosis.

OBJECTIVE

Our objective was to determine whether pancreatic size was reduced in patients with recently diagnosed type 1 diabetes and assess whether pancreatic volume was related to residual β-cell function or islet autoantibodies.

DESIGN AND SETTING

We conducted a controlled cohort study with strict inclusion criteria, recruiting from hospital diabetes clinics between 2007 and 2010. PATIENTS AND HEALTHY CONTROLS: Participants included 20 male adult patients (median age 27 yr) with recent-onset type 1 diabetes (median duration 3.8 months) and 24 male healthy controls (median age 27 yr).

INTERVENTION

Interventions included noninvasive magnetic resonance imaging, collection of fasting blood samples, and glucagon stimulation testing in patients.

MAIN OUTCOME MEASURES

We compared pancreatic volume estimates between patients with recent-onset type 1 diabetes and healthy controls as planned a priori.

RESULTS

Scans were analyzed by an experienced radiologist blinded to diabetes status. Pancreatic volume correlated with body weight in patients and controls (P = 0.007). After adjustment for body weight, mean pancreatic volume index was 26% less in patients (1.19 ml/kg, se 0.07 ml/kg) than in controls (1.61 ml/kg, se 0.08 ml/kg) (P = 0.001). No correlation was seen between pancreatic volume index in patients and diabetes duration, glucose or C-peptide levels, glycated hemoglobin, and islet autoantibodies.

CONCLUSIONS

Pancreatic volume is reduced by 26% in patients with type 1 diabetes within months of diagnosis, suggesting that atrophy begins years before the onset of clinical disease. Pancreatic atrophy within individuals is therefore a potential clinical marker of disease progression.

Magnetic resonance imaging: a reliable method for measuring pancreatic volume in Type 1 diabetes

AIM

To validate magnetic resonance imaging (MRI) for monitoring pancreatic atrophy in Type 1 diabetes.

METHODS

Twelve male patients with Type 1 diabetes of duration >or= 10 years (median age 28, range 19-32 years) and 12 healthy controls (median age 30, range 22-36 years) were invited for two abdominal MRI scans, 14 days apart. Four sequences were used: standard T1-weighted; standard T2-weighted; volumetric interpolated breath-hold examination (VIBE); and T1-weighted breath hold with fat suppression (T1BHFS). The pancreas was identified on coded images by one observer and volumes estimated by interpolation.

RESULTS

Eleven patients and all controls were scanned twice. Visualization of the pancreas was best with VIBE and T1BHFS, allowing volume estimation from 47 and 46 scans, respectively. The pancreatic volume of patients estimated from these sequences were half those of controls (52.4 ml, +/- 17.1 ml, mean +/- sd) vs. (101 ml, +/- 19.5 ml, P < 0.001) and estimates showed little bias between visits; mean difference 1.1 ml (95% CI; -3.1 to 5.3 ml, P = 0.61) using VIBE and -2.6 ml (-5.8 to 0.6 ml, P = 0.03) using T1BHFS. Both sequences gave similar precision; the standard deviation of the differences in volume estimates between visits was 9.7 ml for VIBE and 7.3 ml for T1BHFS, although mean volumes estimated from T1BHFS were 4.9 ml lower (-8.2 to -1.7 ml, P = 0.005).

CONCLUSIONS

Pancreatic volume can be measured reliably using MRI and shows a 48% reduction in long-standing Type 1 diabetes as compared with age-matched normal subjects. MRI should prove useful in determining the natural history of pancreatic atrophy in diabetes.

Life-Threatening Hematuria Requiring Transcatheter Embolization Following Radiofrequency Ablation of Renal Cell Carcinoma

Radiofrequency ablation is increasingly being acknowledged as a valid treatment for renal cell carcinoma in patients in whom definitive curative resection is deemed either undesirable or unsafe. A number of published series have shown the technique to have encouraging results and relatively low complication rates. In this article, we report a case of delayed life-threatening hematuria requiring transcatheter embolization of a bleeding intrarenal artery in a patient who had undergone imaging-guided radiofrequency ablation of a 3 cm renal cell carcinoma. To our knowledge, such a complication has not been reported previously.

The role of preoperative TIPSS to facilitate curative gastric surgery

The use of TIPSS to facilitate radical curative upper gastrointestinal surgery has not been reported. We describe a case in which curative gastric resection was performed for carcinoma of the stomach after a preoperative TIPSS and embolization of a large gastric varix in a patient with portal hypertension.

Chest radiograph interpretation by medical students

AIM

To assess the ability of final year medical students to interpret conventional chest radiographs.

MATERIALS AND METHODS

Ten conventional chest radiographs were selected from a teaching hospital radiology department library that were good radiological examples of common conditions. All were conditions that a medical student should be expected to recognize by the end of their training. One normal radiograph was included. The radiographs were shown to 52 final year medical students who were asked to describe their findings.

RESULTS

The median score achieved was 12.5 out of 20 (range 6-18). There was no difference between the median scores of male and female students (12.5 and 12.3, respectively, p=0.82) but male students were more likely to be certain of their answers than female students (median certainty scores 23.0 and 14.0, respectively). The overall degree of certainty was low. On no radiograph were more than 25% of students definite about their answer. Students had received little formal radiology teaching (2-42 h, median 21) and few expressed an interest in radiology as a career. Only two (3.8%) students thought they were good at interpreting chest radiographs, 17 (32.7%) thought they were bad or awful.

CONCLUSION

Medical students reaching the end of their training do not perform well at interpreting simple chest radiographs. They lack confidence and have received little formal radiological tuition. Perhaps as a result, few are interested in radiology as a career, which is a matter for concern in view of the current shortage of radiologists in the UK.

Treatment of a false aneurysm of an intercostal artery using a covered intracoronary stent-graft and a radial artery puncture

This case report documents the successful treatment of a false aneurysm of the left internal mammary artery with a covered coronary artery stent. The advantages and disadvantages of this novel method of treatment are discussed, together with a review of alternative methods of treatment of false aneurysms.

Middle cranial fossa arachnoid cysts: not always a benign entity

Arachnoid cysts are often discovered as incidental findings on cranial imaging. A rare manifestation is described in a child presenting acutely with symptoms and signs of raised intracranial pressure.

The influence of previous films on screening mammographic interpretation and detection of breast carcinoma

AIM

To establish if the availability of previous mammograms improves the detection rate of carcinomas and reduces supplementary examinations in the National Health Service Breast Screening Programme (NHSBSP).

METHOD

Eight radiologists with varying experience but an interest in reporting mammograms reported 100 mammograms on two occasions, at least 1 month apart. In this selection of 100 mammograms we randomly inserted 12 abnormal films, with both benign and malignant changes present. These were chosen retrospectively with histological correlation of the abnormality. On the first occasion only the current films were reviewed, however, on the second occasion previous films were available for comparison. The films were viewed under standard viewing conditions, and the participants were asked to comment if they required further views or would refer the patient for either an ultrasound examination or surgical referral.

RESULTS

Receiver operating curves (ROC) were constructed for the group's overall performance on each of the occasions and there was no difference in the curves. This indicates that the presence of previous films did not improve diagnostic accuracy. The presence of previous films did, however, lead to a significant reduction in the number of additional views and ultrasound examinations that would have been requested. The most significant reductions occurred in the group of normal mammograms.

CONCLUSION

The presence of previous mammograms does not lead to an improvement in diagnostic accuracy. However, the presence of previous films led to significant reduction in additional examinations and ultrasound examinations.

The incidence of coronary artery calcification on standard thoracic CT scans

Coronary artery calcification indicates the presence of atheromatous disease and can represent an area of severe stenosis. The absence of calcification does not correlate with the absence of coronary artery disease, but an incidental finding of calcification has important prognostic implications. The best method available at present is electron beam computed tomography (EBCT) but these are often dedicated units in specialist centres and currently this modality is not widely available in the UK. This is the first study to establish the age/sex frequency with which incidental coronary artery calcification is detected using standard CT scanning in a large population. The methods used are simple, reproducible and based on standard thoracic protocols. The presence of calcification is easily detected using readily available equipment. The reported incidence of calcification using EBCT, the most sensitive method available, was compared with standard CT detection rates. While standard CT underestimates the presence of calcification, the age/sex trends are very similar. Standard CT probably detects the most dense lesions, missing areas of mild calcification, recent studies having shown that these lesions are most likely to represent areas of stenosis. This study shows that, with very little change in current practice and on readily available equipment, it is possible to obtain important diagnostic information suggesting the presence of severe coronary artery disease.

Chemotherapy induced myocardial fibrosis

Alkylating agents have a well established role in the treatment of malignant disease, with well documented side effects. This case history, however, illustrates the susceptibility to these agents shown by some patients. It is suggested that, when drug induced pneumonitis is noted, careful screening of left ventricular function should be performed in order to diagnose myocardial fibrosis and subsequent cardiac failure.

The incidence of late recurrence (greater than 10 years); an analysis of 536 consecutive cases of cutaneous melanoma

The main purpose of this study was, using a computerised database, to try to establish possible prognostic features shown in patients who develop late recurrence, after 10 years, from a melanoma. The records of 536 patients diagnosed and treated for cutaneous melanoma over a 10-year period were examined and 5 patients were found to have developed a late recurrence. These patients were all female and included both pre- and post-menopausal cases at the time of initial diagnosis. In 4 out of the 5 cases the primary lesion had been situated upon an extremity. This study adds to the evidence that prognostic indicators can lead to a possible identification of high risk patients and that the level of patient awareness and education must be maintained throughout the period of follow-up.