Imaging of non-traumatic abdominal emergencies in adults

The value of radiomics-based CT combined with machine learning in the diagnosis of occult vertebral fractures

PURPOSE

To develop and evaluate the performance of radiomics-based computed tomography (CT) combined with machine learning algorithms in detecting occult vertebral fractures (OVFs).

MATERIALS AND METHODS

128 vertebrae including 64 with OVF confirmed by magnetic resonance imaging and 64 corresponding control vertebrae from 57 patients who underwent chest/abdominal CT scans, were included. The CT radiomics features on mid-axial and mid-sagittal plane of each vertebra were extracted. The fractured and normal vertebrae were randomly divided into training set and validation set at a ratio of 8:2. Pearson correlation analyses and least absolute shrinkage and selection operator were used for selecting sagittal and axial features, respectively. Three machine-learning algorithms were used to construct the radiomics models based on the residual features. Receiver operating characteristic (ROC) analysis was used to verify the performance of model.

RESULTS

For mid-axial CT imaging, 6 radiomics parameters were obtained and used for building the models. The logistic regression (LR) algorithm showed the best performance with area under the ROC curves (AUC) of training and validation sets of 0.682 and 0.775. For mid-sagittal CT imaging, 5 parameters were selected, and LR algorithms showed the best performance with AUC of training and validation sets of 0.832 and 0.882. The LR model based on sagittal CT yielded the best performance, with an accuracy of 0.846, sensitivity of 0.846, and specificity of 0.846.

CONCLUSION

Machine learning based on CT radiomics features allows for the detection of OVFs, especially the LR model based on the radiomics of sagittal imaging, which indicates it is promising to further combine with deep learning to achieve automatic recognition of OVFs to reduce the associated secondary injury.

Efficacy and confounding factors of CT attenuation value differences in distinguishing acute and old vertebral compression fractures: a retrospective study

PURPOSE

To evaluate the influence of various factors on CT attenuation values (HUs) of acute and old fracture vertebra, and to determine the efficacy of HU differences (△HUs) in the differentiation of the two type of fractures.

MATERIALS AND METHODS

A total of 113 acute and 71 old fracture vertebrae confirmed by MRI were included. Four HUs measured at the mid-sagittal, upper 1/3 axial, mid-axial, and lower 1/3 axial planes of each vertebra were obtained. The △HUs between fracture vertebra and its control counterpart was calculated. Receiver operating characteristic (ROC) curve analysis was used and the areas under the ROC curve (AUC) were calculated to evaluate the efficacy of HUs and △HUs. To evaluate the effect of height reduction, region, age and gender on HUs and △HUs, one-way analysis of variance, Pearson correlation analysis and t-test were used.

RESULTS

The HUs and △HUs at the upper 1/3 axial plane achieved the highest AUCs of 0.801 and 0.839, respectively. The HUs decreased gradually from Thoracic to Lumbar in control group of acute fracture. While no significant differences were found in the HUs among the 3 localizations in both fracture groups (all P > 0.05). The HUs were negatively correlated with age in all groups. The HUs of male were significantly higher than female patients in all groups (all P < 0.05). While △HU was not significantly different between males and females (all P > 0.05).

CONCLUSION

The vertebral HUs at the upper 1/3 axial plane are more likely to identify acute fractures. △HUs were beneficial in eliminating interfering factors.

Causes of acute abdomen, preferred imaging methods, and prognoses in geriatric patients presenting to the emergency department with abdominal pain

OBJECTIVE

Abdominal pain is one of the most common reasons for admission to the emergency department in the geriatric population. The aim of this study was to investigate the diseases frequently detected in elderly patients diagnosed with acute abdomen in the emergency department, the imaging methods used in the diagnostic processes of these diseases, and the prognosis of the patients.

METHODS

In all, 175 patients who visited the emergency department due to abdominal pain and were hospitalized with a diagnosis of acute abdomen were evaluated. The patients were categorized into seven groups according to their diagnosis as biliary diseases, pancreatitis, appendicitis, gastrointestinal system perforation, ileus, mesenteric ischemia, and atypical causes.

RESULTS

The mean age of the patients was 76.3±7.7 years (range 65-93), and 96 (54.9%) were women. The most common causes of acute abdomen were biliary diseases and pancreatitis. Ultrasonography (88.6%) was the most frequently preferred imaging method in the emergency department, and it was most frequently used for biliary diseases. Notably, 20 (11.4%) patients were treated in the intensive care unit, and 9 (5.1%) patients died.

CONCLUSION

The most common causes of acute abdomen in the geriatric population were biliary diseases and pancreatitis, and ultrasonography imaging was the most common choice for the diagnosis of these diseases. In elderly patients with abdominal pain, rapid and accurate diagnosis and selection of the correct imaging method are extremely important.

Reducing length of stay for patients presenting to general surgery with acute non-surgical abdominal pain

BACKGROUND

Acute abdominal pain is a common surgical presentation. We previously found that over the last decade, more patients were admitted to hospital with non-surgical diagnoses (e.g. gastroenteritis, constipation and non-specific abdominal pain) and length of stay and use of imaging (mainly computed tomography scan) for these patients increased. This study aimed to reduce length of stay and use of imaging for patients admitted with non-surgical abdominal pain.

METHODS

A prospective study was undertaken in a tertiary centre evaluating length of stay and use of additional imaging in patients with a non-surgical diagnosis after a quality improvement intervention was implemented.

RESULTS

A total of 454 patients were included; 204 (44.9%) presented with non-surgical abdominal pain. During the study period, a significant reduction in computed tomography scan requests was observed (38.5-25.0%, P = 0.037) and an increasing proportion of these patients were discharged within 12 h (33.3-57.1%, P = 0.018). The number of re-presentations remained unchanged (P = 0.358).

CONCLUSIONS

The study intervention increased the proportion of patients with non-surgical diagnoses that were successfully discharged within 12 h and reduced the use of additional imaging in this group. This may lead to improved use of health care resources for patients with more urgent diagnoses.

Evaluation of the CT Scan as the First Examination for the Diagnosis and Therapeutic Strategy for Acute Cholecystitis

BACKGROUND

The CT scan has supplanted the abdominal ultrasound for emergency examinations. A comparison of CT scan and ultrasound performance for the diagnosis and management of acute cholecystitis in acute care was proposed. The hypothesis is that the CT scan may be sufficient for the diagnosis of acute cholecystitis, which would allow faster progress to surgery.

METHODS

The retrospective study of consecutive patients operated for acute cholecystitis or gallbladder distension with pre-operative imaging within 48 h in one centre.

RESULTS

Between 2015 and 2017, a total of 341 cholecystectomies were performed in our centre. The analysis involved 120 patients. Ultrasound had better sensitivity than the CT scan, respectively, 79.4% [70.5-86.6] and 52.3% [42.5-62.1], but less specificity, with 61.5% [31.6-86.1] and 92.3% [64.0-99.8], respectively. However, there was a significant difference in favour of the CT scan for the diagnosis of complicated cholecystitis (p 0.004). The positive likelihood ratio of complicated cholecystitis is better at CT scan (7.8) [2.7-23.1] than in ultrasound (1.0) [0.1-9.7]. CT scan and ultrasound are equivalent for the diagnosis of acute cholecystitis, but CT scan is more efficient for the diagnosis of complicated cases (Youden index J 0.3 vs 0.001).

CONCLUSION

It is possible to place the surgical indication of cholecystectomy on the only data of the CT scan. We propose a decision-making algorithm that uses the CT scan to make the diagnosis and decide on emergency treatment for complicated cases or that allows us to propose a delayed surgery for simple cholecystitis.

Diagnostic imaging for acute abdominal pain in an Emergency Department in Italy

Imaging plays a key role in the diagnostic work-up of patients with non-traumatic acute abdominal pain (AAP) in emergency department (ED). We aimed to evaluate the use and diagnostic performance of imaging techniques in adult patients with AAP in an ED in Italy. Patients with non-traumatic AAP admitted at the ED of S. Orsola-Malpighi University Hospital of Bologna (Italy) from the 1st to the 30th November 2016 were included. Demographic and clinical data, data on radiological procedures and discharge diagnosis were collected. Sensitivity and specificity for detecting acute diseases were assessed using the discharge diagnosis from the ED as reference standard. Of the 578 patients (female 52.8%, mean age 51.3 years) admitted to the ED for AAP, 433 (74.9%) underwent abdominal imaging. The most frequent techniques used were abdominal plain radiography and ultrasonography (US), performed in 38.4% and 37.9% of patients, respectively, followed by computed tomography (CT) in 28% of patients. Plain radiography yielded a sensitivity of 28% and specificity of 91.1%; the sensitivity increased to 79.4% in patients with small bowel obstruction. Ultrasonography's sensitivity and specificity were 61.8% and 98.4%, respectively; the sensitivity of US reached 85.2% and 90% in patients with acute cholecystitis/biliary colic and urolithiasis, respectively. The sensitivity and specificity of CT were 87.8% and 92.9%, respectively. Plain radiography is still overused in the diagnostic work-up of AAP in ED in Italy, despite its unsatisfactory sensitivity. Ultrasonography and CT has a higher sensitivity and should be used as first-level imaging in most patients.

Laparoscopy in the second and third trimesters of pregnancy for abdominal surgical emergencies

OBJECTIVE

To assess complications and outcomes of pregnancies following laparoscopic abdominal surgery during the second and third trimesters of pregnancy.

MATERIAL AND METHODS

Retrospective single-center study of 23 cases of laparoscopic surgery in the second or third trimesters of pregnancy between January 2005 and May 2016.

RESULTS

The laparoscopies were performed between 15 and 33 weeks of gestation, a mean of 23 weeks+2 days, with 6 cases in the 3rd trimester. The operations were: 11 cholecystectomies, 6 appendectomies, 1 intestinal occlusion (volvulus on a gastric band), 3 adnexal torsions, 1 ovarian cyst and 1 paratubal cyst with torsion. No secondary laparotomy was required. The postoperative courses were favorable in most cases. However, 3 appendectomies were complicated, one by chorioamnionitis and miscarriage at 20½ weeks of gestation and 2 by right iliac fossa abscesses requiring percutaneous radiological drainage, one of these women delivered a healthy term baby and the other had chorioamnionitis and preterm delivery at 34 weeks, followed by neonatal death.

CONCLUSION

Laparoscopy can be safely performed for surgical indications in the second and third trimesters of pregnancy. In case of abdominal symptoms, a timely diagnosis is required to decide whether or not to operate and imaging should not be withheld particularly in case of suspected appendicitis which has a high risk of complications.