Managing silent threats: Unveiling gangrenous complication in acute emphysematous cholecystitis

Emphysematous cholecystitis is a potentially life-threatening variant of acute cholecystitis, characterized by the presence of gas in the gallbladder wall/lumen due to the proliferation of gas-producing bacteria. Symptoms include upper right quadrant pain, fever, nausea, and vomiting. Laboratory tests may show nonspecific indications of systemic infection, and radiological assessment, especially CT scanning, is crucial for diagnosis. This case underscores the significance of early diagnosis and intervention in managing emphysematous cholecystitis to prevent serious complications and reduce the higher mortality rate compared to acute cholecystitis.

Cholangiocarcinoma imaging: from diagnosis to response assessment

Cholangiocarcinoma (CCA), a highly aggressive primary liver cancer arising from the bile duct epithelium, represents a substantial proportion of hepatobiliary malignancies, posing formidable challenges in diagnosis and treatment. Notably, the global incidence of intrahepatic CCA has seen a rise, necessitating a critical examination of diagnostic and management strategies, especially due to presence of close imaging mimics such as hepatocellular carcinoma (HCC) and combined hepatocellular carcinoma-cholangiocarcinoma (cHCC-CCA). Hence, it is imperative to understand the role of various imaging modalities such as ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI), elucidating their strengths, and limitations in diagnostic precision and staging accuracy. Beyond conventional approaches, there is emerging significance of functional imaging tools including positron emission tomography (PET)-CT and diffusion-weighted (DW)-MRI, providing pivotal insights into diagnosis, therapeutic assessment, and prognostic evaluation. This comprehensive review explores the risk factors, classification, clinical features, and role of imaging in the holistic spectrum of diagnosis, staging, management, and restaging for CCA, hence serving as a valuable resource for radiologists evaluating CCA.

Improving abdominal image segmentation with overcomplete shape priors

The extraction of abdominal structures using deep learning has recently experienced a widespread interest in medical image analysis. Automatic abdominal organ and vessel segmentation is highly desirable to guide clinicians in computer-assisted diagnosis, therapy, or surgical planning. Despite a good ability to extract large organs, the capacity of U-Net inspired architectures to automatically delineate smaller structures remains a major issue, especially given the increase in receptive field size as we go deeper into the network. To deal with various abdominal structure sizes while exploiting efficient geometric constraints, we present a novel approach that integrates into deep segmentation shape priors from a semi-overcomplete convolutional auto-encoder (S-OCAE) embedding. Compared to standard convolutional auto-encoders (CAE), it exploits an over-complete branch that projects data onto higher dimensions to better characterize anatomical structures with a small spatial extent. Experiments on abdominal organs and vessel delineation performed on various publicly available datasets highlight the effectiveness of our method compared to state-of-the-art, including U-Net trained without and with shape priors from a traditional CAE. Exploiting a semi-overcomplete convolutional auto-encoder embedding as shape priors improves the ability of deep segmentation models to provide realistic and accurate abdominal structure contours.

Image quality of abdominal photon-counting CT with reduced contrast media dose: Evaluation of reduced contrast media protocols during the COVID19 pandemic supply shortage

Rationale and objectives

Aim of this study was to assess the impact of contrast media dose (CMD) reduction on diagnostic quality of photon-counting detector CT (PCD-CT) and energy-integrating detector CT (EID-CT).

Methods

CT scans of the abdominal region with differing CMD acquired in portal venous phase on a PCD-CT were included and compared to EID-CT scans. Diagnostic quality and contrast intensity were rated. Additionally, readers had to assign the scans to reduced or regular CMD. Regions-of-interest (ROIs) were placed in defined segments of portal vein, inferior vena cava, liver, spleen, kidneys, abdominal aorta and muscular tissue. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated.

Results

Overall 158 CT scans performed on a PCD-CT and 68 examinations on an EID-CT were analyzed. Overall diagnostic quality showed no significant differences for PCD-CT with standard CMD which scored a median 5 (IQR:5-5) and PCD-CT with 70% CMD scoring 5 (4-5). (For PCD-CT, 71.69% of the examinations with reduced CMD were assigned to regular CMD by the readers, for EID-CT 9.09%. Averaged for all measurements SNR for 50% CMD was reduced by 19% in PCD-CT (EID-CT 34%) and CNR by 48% (EID-CT 56%). Virtual monoenergetic images (VMI)50keV for PCD-CT images acquired with 50% CMD showed an increase in SNR by 72% and CNR by 153%.

Conclusions

Diagnostic interpretability of PCD-CT examinations with reduction of up to 50% CMD is maintained. PCD-CT deducted scans especially with 70% CMD were often not recognized as CMD reduced scans. Compared to EID-CT less decline in SNR and CNR is observed for CMD reduced PCD-CT images. Employing VMI50keV for CMD-reduced PCD-CT images compensated for the effects.

Influence of spectral shaping and tube voltage modulation in ultralow-dose computed tomography of the abdomen

PURPOSE

Unenhanced abdominal CT constitutes the diagnostic standard of care in suspected urolithiasis. Aiming to identify potential for radiation dose reduction in this frequent imaging task, this experimental study compares the effect of spectral shaping and tube voltage modulation on image quality.

METHODS

Using a third-generation dual-source CT, eight cadaveric specimens were scanned with varying tube voltage settings with and without tin filter application (Sn 150, Sn 100, 120, 100, and 80 kVp) at three dose levels (3 mGy: standard; 1 mGy: low; 0.5 mGy: ultralow). Image quality was assessed quantitatively by calculation of signal-to-noise ratios (SNR) for various tissues (spleen, kidney, trabecular bone, fat) and subjectively by three independent radiologists based on a seven-point rating scale (7 = excellent; 1 = very poor).

RESULTS

Irrespective of dose level, Sn 100 kVp resulted in the highest SNR of all tube voltage settings. In direct comparison to Sn 150 kVp, superior SNR was ascertained for spleen (p ≤ 0.004) and kidney tissue (p ≤ 0.009). In ultralow-dose scans, subjective image quality of Sn 100 kVp (median score 3; interquartile range 3-3) was higher compared with conventional imaging at 120 kVp (2; 2-2), 100 kVp (1; 1-2), and 80 kVp (1; 1-1) (all p < 0.001). Indicated by an intraclass correlation coefficient of 0.945 (95% confidence interval: 0.927-0.960), interrater reliability was excellent.

CONCLUSIONS

In abdominal CT with maximised dose reduction, tin prefiltration at 100 kVp allows for superior image quality over Sn 150 kVp and conventional imaging without spectral shaping.

Abdominal MRI on a Commercial 0.55T System: Initial Evaluation and Comparison to Higher Field Strengths

RATIONALE AND OBJECTIVES

This study aims to assess the quality of abdominal MR images acquired on a commercial 0.55T scanner and compare these images with those acquired on conventional 1.5T/3T scanners in both healthy subjects and patients.

MATERIALS AND METHODS

Fifteen healthy subjects and 52 patients underwent abdominal Magnetic Resonance Imaging at 0.55T. Images were also collected in healthy subjects at 1.5T, and comparison 1.5/3T images identified for 28 of the 52 patients. Image quality was rated by two radiologists on a 4-point Likert scale. Readers were asked whether they could answer the clinical question for patient studies. Wilcoxon signed-rank test was used to test for significant differences in image ratings and acquisition times, and inter-reader reliability was computed.

RESULTS

The overall image quality of all sequences at 0.55T were rated as acceptable in healthy subjects. Sequences were modified to improve signal-to-noise ratio and reduce artifacts and deployed for clinical use; 52 patients were enrolled in this study. Radiologists were able to answer the clinical question in 52 (reader 1) and 46 (reader 2) of the patient cases. Average image quality was considered to be diagnostic (>3) for all sequences except arterial phase FS 3D T1w gradient echo (GRE) and 3D magnetic resonance cholangiopancreatography for one reader. In comparison to higher field images, significantly lower scores were given to 0.55T IP 2D GRE and arterial phase FS 3D T1w GRE, and significantly higher scores to diffusion-weighted echo planar imaging at 0.55T; other sequences were equivalent. The average scan time at 0.55T was 54 ± 10 minutes vs 36 ± 11 minutes at higher field strengths (P < .001).

CONCLUSION

Diagnostic-quality abdominal MR images can be obtained on a commercial 0.55T scanner at a longer overall acquisition time compared to higher field systems, although some sequences may benefit from additional optimization.

Spontaneous splenic rupture in a neonate: a case report and literature review

Splenic rupture in a neonate is a rare but potentially fatal condition that may trigger evaluation for child abuse. It is a diagnosis of exclusion that has been reported in the surgical literature but may be underrecognized by pediatric radiologists. We report a case of a newborn with an unremarkable prenatal, delivery, and nursery course who presented with anemia, abdominal distension, and lethargy. Abdominal ultrasound with Doppler and computed tomography (CT) of the head, cervical spine, chest, abdomen, and pelvis without contrast showed findings of splenic rupture and anoxic brain injury. An extensive workup for traumatic, infectious, coagulopathic, and congenital etiologies was unrevealing, leading to a presumptive diagnosis of spontaneous splenic rupture in a neonate.

Prevalence of intra-abdominal injury among patients with seatbelt signs, a systematic review and meta-analysis

INTRODUCTION

The advancement of seat belts have been essential to reducing morbidity and mortality related to motor vehicle collisions (MVCs). The "seat belt sign" (SBS) is an important physical exam finding that has guided management for decades. This study, comprising a systematic review and random-effects meta-analysis, asses the current literature for the likelihood of the SBS relating to intra-abdominal injury and surgical intervention.

METHODS

PubMed and Scopus databases were searched from their beginnings through August 4, 2023 for eligible studies. Outcomes included the prevalence of intra-abdominal injury and need for surgical intervention. Cochrane's Risk of Bias (RoB) tool and the Newcastle-Ottawa Scale (NOS) were applied to assess risk of bias and study quality; Q-statistics and I2 values were used to assess for heterogeneity.

RESULTS

The search yielded nine observational studies involving 3050 patients, 1937 (63.5%) of which had a positive SBS. The pooled prevalence of any intra-abdominal injury was 0.42, (95% CI 0.28-0.58, I2 = 96%) The presence of a SBS was significantly associated with increased odds of intra-abdominal injury (OR 3.62, 95% CI 1.12-11.6, P = 0.03; I2 = 89%), and an increased likelihood of surgical intervention (OR 7.34, 95% CI 2.03-26.54, P < 0.001; I2 = 29%). The measurement for any intra-abdominal injury was associated with high heterogeneity, I2 = 89%.

CONCLUSION

This meta-analysis suggests that the presence of a SBS was associated with a statistically significant higher likelihood of intra-abdominal injury and need for surgical intervention. The study had high heterogeneity, likely due to the technological advancements over the course of this study, including seat belt design and diagnostic imaging sensitivity. Further studies with more recent data are needed to confirm these results.

Rare case report of intestinal obstruction due to incarcerated small bowel in omental breach

INTRODUCTION AND IMPORTANCE

Intestinal obstruction without a past surgical history of abdominal surgeries or trauma is a rare and challenging clinical situation. This case report describes the presentation, diagnosis, and management of intestinal obstruction in a patient with an uncommon aetiology of small bowel obstruction.

CASE PRESENTATION

A 62-year-old female with a past medical history of hypertension, diabetes, and atrial fibrillation presented to the Emergency Department with symptoms of vomiting and abdominal distension for two days. The absence of similar prior episodes and lack of surgical or trauma history were notable. Physical examination revealed a mildly distended, tympanic abdomen. Radiographic X-ray and CT imaging identified dilated small bowel loops due to a mechanical small bowel obstruction without any evident aetiology. Surgical intervention involved the release of the incarcerated bowel loops and repair of the omental breach causing the small bowel obstruction, leading to a smooth postoperative recovery.

DISCUSSION

This case of intestinal obstruction, caused by an incarcerated bowel through an omental breach in a patient with no history of abdominal surgery or trauma, underscores the diagnostic challenges in atypical presentations. The critical role of imaging, specifically abdominal X-ray and CT scan, was key in identifying the rare obstruction cause. The successful surgical release and repair of the incarcerated bowel highlight the need for tailored surgical approaches. This report emphasizes the importance of considering uncommon etiologies and demonstrates the complexities involved in the diagnosis and treatment of gastrointestinal conditions, advocating for a multidisciplinary approach.

CONCLUSIONS

The importance of considering rare etiologies in patients with abdominal pain, especially those lacking a typical history, is emphasized. The effective use of imaging and tailored surgical approach was key to the successful outcome. This report adds to the limited literature on omental breaches causing intestinal obstruction and underlines the necessity of a multidisciplinary approach in such cases.

Metastatic melanoma presenting as rapidly enlarging hepatic cysts

Malignant melanoma is a highly aggressive disease with a propensity for metastatic spread. Although recent advances in targeted therapies have improved outcomes, effective screening for metastasis remains an important area of further research. We present a case of a man in his 70s who was recently diagnosed with recurrent, locally advanced melanoma. He presented with abdominal fullness, jaundice, and poor appetite. MR imaging of the abdomen revealed innumerable hepatic cysts with internal fluid-fluid levels which were markedly increased in size and number from recent imaging. These findings necessitated a broad differential that included parasitic or bacterial infection, metastases, or drug-induced polycystic liver disease. Subsequent biopsy revealed metastatic melanoma consistent with the patient's primary tumor. The patient was ultimately transitioned to comfort care measures due to the burden of the liver metastases and passed away shortly after presentation.

Photoacoustic clinical applications: Musculoskeletal and abdominal imaging

Photoacoustic (PA) imaging has been extensively investigated in application in biomedicine over the last decade. This article reviews the motivation, significance, and system configuration of a few ongoing studies of implementing photoacoustic technology in musculoskeletal imaging, abdominal imaging, and interstitial sensing. The review then summarizes the methodologies and latest progress of relevant projects. Finally, we discuss our expectations for the future of translation research in PA imaging.

Parsimonious clinical prediction model for the diagnosis of complicated appendicitis

Objective

To develop a logistic regression model that combines clinical and radiological parameters for prediction of complicated appendicitis.

Methods

248 patients with histologically proven uncomplicated (n = 214) and complicated (n = 34) acute appendicitis were analyzed retrospectively. All patients had undergone a presurgical abdominal and/or pelvic computed tomography (CT) scan, assessed by two radiologists. A model using univariate and multivariate logistic regression analyses was developed, and the strength of association between independent predictors and complicated acute appendicitis was evaluated by adjusted odds radio. Clinical parameters were gender, age, anorexia, vomiting, duration of symptoms, right lower abdominal quadrant (RLQ) tenderness, rebound tenderness, body temperature, white blood cell (WBC) count, and neutrophil ratio. Radiological parameters were appendix diameter, appendicolith, caecal wall thickening, mesenteric lymphadenopathy, extraluminal air, abscess, fat stranding, and periappendicular fluid.

Results

Four features (body temperature＞37.2 °C, vomiting, appendicolith, and periappendiceal fluid) were included in the logistic regression model, and yielded an area under the curve (AUC) of 0.87 (95% confidence interval (CI), 0.80-0.93), sensitive of 88%, and specificity of 74%.

Conclusion

The logistic regression model makes an accurate and simple prediction of complicated appendicitis possible.

Abdominal peer learning: advantages and lessons learned

In 2017, our tertiary hospital-based imaging practice transitioned from score-based peer review to the peer learning methodology for learning and improvement. In our subspecialized practice, peer learning submissions are reviewed by domain experts, who then provide feedback to individual radiologists, curate cases for group learning sessions, and develop associated improvement initiatives. In this paper, we share lessons learned from our abdominal imaging peer learning submissions with the assumption that trends in our practice likely mimic others', and hope that other practices can avoid future errors and elevate the level of the quality of their own performance. Adoption of a nonjudgmental and efficient method to share peer "learning opportunities" and "great calls" has increased participation in this activity and increased transparency into our practice, thus allowing for visualization of trends in performance. Peer learning allows us to bring our own individual knowledge and practices together for group review in a collegial and safe environment. We learn from each other and decide how to improve together.

Portal vein aneurysm-etiology, multimodal imaging and current management

Portal vein aneurysm (PVA) is a rare vascular abnormality, representing 3% of all venous aneurysms in the human body, and is not well understood. It can be congenital or acquired, located mainly at the level of confluence, main trunk, branches and bifurcation. A PVA as an abnormality of the portal venous system was first reported in 1956 by Barzilai and Kleckner. A review from 2015 entitled “Portal vein aneurysm: What to know” considered fewer than 200 cases. In the last seven years, there has been an increase in the number of PVAs diagnosed thanks to routine abdominal imaging. The aim of this review is to provide a comprehensive update of PVA, including aetiology, epidemiology, and clinical assessment, along with an evaluation of advanced multimodal imaging features of aneurysm and management approaches.

Performance of threshold-based stone segmentation and radiomics for determining the composition of kidney stones from single-energy CT

PURPOSE

Knowledge of kidney stone composition can help in patient management; urine composition analysis and dual-energy CT are frequently used to assess stone type. We assessed if threshold-based stone segmentation and radiomics can determine the composition of kidney stones from single-energy, non-contrast abdomen-pelvis CT.

METHODS

With IRB approval, we identified 218 consecutive patients (mean age 64 ± 13 years; male:female 138:80) with the presence of kidney stones on non-contrast, abdomen-pelvis CT and surgical or biochemical proof of their stone composition. CT examinations were performed on one of the seven multidetector-row scanners from four vendors (GE, Philips, Siemens, Toshiba). Deidentified CT images were processed with a radiomics prototype (Frontier, Siemens Healthineers) to segment the entire kidney volumes with an AI-based organ segmentation tool. We applied a threshold of 130 HU to isolate stones in the segmented kidneys and to estimate radiomics over the segmented stone volume. A coinvestigator verified kidney stone segmentation and adjusted the volume of interest to include the entire stone volume when necessary. We applied multiple logistic regression tests with precision recall plots to obtain area under the curve (AUC) using a built-in R statistical program.

RESULTS

The threshold-based stone segmentation successfully isolated kidney stones (uric acid: n = 102 patients, calcium oxalate/phosphate: n = 116 patients) in all patients. Radiomics differentiated between calcium and uric acid stones with an AUC of 0.78 (p < 0.01, 95% CI 0.73-0.83), 0.79 sensitivity, and 0.90 specificity regardless of CT vendors (GE CT: AUC = 0.82, p < 0.01, 95% CI 0.740-0896; Siemens CT: AUC = 0.77, 95% CI 0.700-0.846, p < 0.01).

CONCLUSION

Automated threshold-based stone segmentation and radiomics can differentiate between calcium oxalate/phosphate and urate stones from non-contrast, single-energy abdomen CT.

Understanding abdominal pelvic computerized tomography scan usage amongst adolescent blunt trauma patients treated at adult trauma centers

INTRODUCTION

The algorithm for evaluating adolescent patients with blunt trauma includes abdominal pelvic CT (APCT). The aim of this study is to evaluate the utility of APCT in this context.

METHODS

We performed a retrospective review of adolescent (11 to 18 years of age) blunt trauma patients at an urban adult level 1 trauma center from January 2015 to December 2019. The primary outcome was the prevalence of positive findings on APCT scan.  Additionally, clinical risk factors concerning for intra-abdominal injury were analyzed.

RESULTS

There were 546 patients evaluated for blunt trauma and the prevalence of APCT within the population was 59.3% (95% CI 54.2%-64.9%). Of the patients who received APCT, 123 (37.9%) had positive findings on APCT. Only 25 patients (7.7% of those who underwent APCT) required abdominal surgery while 40 patients (12.3%) had intraabdominal injury that did not require surgery. Risk factors were present in 100% of patients with intraabdominal injury and absent in 28.7% of patients without intraabdominal injury. Abnormal abdominal exam, abnormal FAST, positive chest x-ray and elevated transaminases were independently associated with intraabdominal injury.

CONCLUSIONS

Our study found that adolescent blunt trauma patients treated at our trauma center had a higher rate of APCT usage, but a comparable rate of positive findings when compared with the most recent literature. Future studies should focus on reducing the number of patients who undergo APCT despite an absence of clinical risk factors.

Abdominal splenosis mimicking peritoneal carcinomatosis of ovarian cancer

We present the clinical case of a 53-year-old woman referred for suspicion of recurrence of a mesonephric-like adenocarcinoma of the ovary. Abdominal and pelvic CT revealed multiple round/oval solid nodules with similar density scattered throughout the abdomen and pelvis, the biggest ones appearing in the left hypochondrium; no normal-appearing spleen or ascites were observed. These radiological findings and the absence of significant elevation of CA 125 levels made the radiologists hypothesize that these aspects were related to abdominal splenosis. They asked the patient about previous medical history of splenic injury, which she confirmed, referring it was a consequence of a remote major trauma. A ^99mTc-labeled heat-denatured erythrocytes (^99mTc-DRBC) scintigraphy/ hybrid SPECT/CT was then performed for definitive diagnosis; it showed spleen remnants as foci of increased radiopharmaceutical uptake in the same locations as the nodules appearing in the CT. This diagnostic work-up was consistent with abdominal splenosis, mimicking peritoneal carcinomatosis of ovarian cancer.

Imaging biomarkers to stratify lymph node metastases in abdominal CT - Is radiomics superior to dual-energy material decomposition?

Purpose

To assess the potential of radiomic features in comparison to dual-energy CT (DECT) material decomposition to objectively stratify abdominal lymph node metastases.

Materials and methods

In this retrospective study, we included 81 patients (m, 57; median age, 65 (interquartile range, 58.7-73.3) years) with either lymph node metastases (n = 36) or benign lymph nodes (n = 45) who underwent contrast-enhanced abdominal DECT between 06/2015-07/2019. All malignant lymph nodes were classified as unequivocal according to RECIST criteria and confirmed by histopathology, PET-CT or follow-up imaging. Three investigators segmented lymph nodes to extract DECT and radiomics features. Intra-class correlation analysis was applied to stratify a robust feature subset with further feature reduction by Pearson correlation analysis and LASSO. Independent training and testing datasets were applied on four different machine learning models. We calculated the performance metrics and permutation-based feature importance values to increase interpretability of the models. DeLong test was used to compare the top performing models.

Results

Distance matrices and t-SNE plots revealed clearer clusters using a combination of DECT and radiomic features compared to DECT features only. Feature reduction by LASSO excluded all DECT features of the combined feature cohort. The top performing radiomic features model (AUC = 1.000; F1 = 1.000; precision = 1.000; Random Forest) was significantly superior to the top performing DECT features model (AUC = 0.942; F1 = 0.762; precision = 0.800; Stochastic Gradient Boosting) (DeLong < 0.001).

Conclusion

Imaging biomarkers have the potential to stratify unequivocal lymph node metastases. Radiomics models were superior to DECT material decomposition and may serve as a support tool to facilitate stratification of abdominal lymph node metastases.

Interventional management and diagnostic follow-up of a large pancreatic pseudocyst: A case report

We present a case of a large pancreatic pseudocyst in a 69-year-old man following post biopsy pancreatitis. Radiological findings revealed a thick-walled, fluid filled mass in proximity to the pancreas. Although pancreatic pseudocysts generally self-resolve, extensive or complicated cysts may require surgical or interventional management. Pseudocyst size >6 cm, compression of the inferior vena cava or biliary duct, and severe symptoms often prognosticate the need for intervention.

Natural Language Processing for Imaging Protocol Assignment: Machine Learning for Multiclass Classification of Abdominal CT Protocols Using Indication Text Data

A correct protocol assignment is critical to high-quality imaging examinations, and its automation can be amenable to natural language processing (NLP). Assigning protocols for abdominal imaging CT scans is particularly challenging given the multiple organ specific indications and parameters. We compared conventional machine learning, deep learning, and automated machine learning builder workflows for this multiclass text classification task. A total of 94,501 CT studies performed over 4 years and their assigned protocols were obtained. Text data associated with each study including the ordering provider generated free text study indication and ICD codes were used for NLP analysis and protocol class prediction. The data was classified into one of 11 abdominal CT protocol classes before and after augmentations used to account for imbalances in the class sample sizes. Four machine learning (ML) algorithms, one deep learning algorithm, and an automated machine learning (AutoML) builder were used for the multilabel classification task: Random Forest (RF), Tree Ensemble (TE), Gradient Boosted Tree (GBT), multi-layer perceptron (MLP), Universal Language Model Fine-tuning (ULMFiT), and Google’s AutoML builder (Alphabet, Inc., Mountain View, CA), respectively. On the unbalanced dataset, the manually coded algorithms all performed similarly with F1 scores of 0.811 for RF, 0.813 for TE, 0.813 for GBT, 0.828 for MLP, and 0.847 for ULMFiT. The AutoML builder performed better with a F1 score of 0.854. On the balanced dataset, the tree ensemble machine learning algorithm performed the best with an F1 score of 0.803 and a Cohen’s kappa of 0.612. AutoML methods took a longer time for completion of NLP model training and evaluation, 4 h and 45 min compared to an average of 51 min for manual methods. Machine learning and natural language processing can be used for the complex multiclass classification task of abdominal imaging CT scan protocol assignment.

Ruptured endometrioma in a nonpregnant patient: a case report

Background

Endometriomas are a type of ovarian cyst composed of degenerated blood products from hemorrhage of ectopic endometrial tissue. Endometriomas can rupture, causing hemoperitoneum, and present with signs and symptoms similar to other, more common abdominal emergencies. Therefore, they are not often diagnosed preoperatively. Ultrasound and cross-sectional imaging can assist in diagnosis of endometriomas. We present a case of ruptured endometrioma causing massive hemoperitoneum that was initially suspected to represent malignancy with carcinomatosis.

Case presentation

A 32-year-old Hispanic woman presented with sharp abdominal pain and 15-pound unintentional weight loss over 6 months. Laboratory work was significant for a negative pregnancy test and elevated cancer antigen-125. Computed tomography of the abdomen and pelvis demonstrated a 13-cm complex cystic mass in the left adnexa with moderate hyperdense ascites and omental nodularity. Ultrasound demonstrated a large left adnexal complex cystic structure with internal echoes, and chest computed tomography showed no signs of intrathoracic neoplastic or infectious processes. Her presentation was concerning for malignancy with carcinomatosis. Fluid from a paracentesis was sent for culture and cytology. Diagnostic laparoscopy revealed that the left ovary had been completely replaced by an endometrioma, which had a small ruptured area superiorly. Brown deposits of endometriosis were present on the cyst, omentum, and various peritoneal linings. Tissue samples of the endometrium, myometrium, cervix, ovaries, fallopian tubes, peritoneum, omentum, and paracolic spaces were taken and showed no hyperplastic, dysplastic, or malignant cells on pathology.

Conclusions

Ruptured endometrioma and ruptured hemorrhagic cyst should be included in the differential diagnosis when a premenopausal female presents with hemoperitoneum in combination with complex adnexal cystic masses in the absence of trauma. Cancer antigen-125 and cancer antigen 19-9 can be falsely elevated in the setting of ruptured endometrioma.

Inflammatory bowel disease causing retroperitoneal varicosity mimicking a renal artery aneurysm: A novel case report and literature review

A 17-year-old female presented to our hospital complaining of bloody diarrhea 4-6 times per day for the past month. She was a known case of inflammatory bowel disease noncompliant to her medications. Abdominal computed tomography revealed an unusually dilated mass in the retroperitoneum at L2 vertebral level connecting the lumbar and left renal veins. The renal artery was visualized separately, and a diagnosis of communicating vein varicosity was made. This lesion can be misleading on imaging, hence our aim to disseminate our findings to practicing radiologists. The differential diagnosis of these lesions include retroperitoneal lymphadenopathy, renal artery aneurysms, and testicular cancers causing retroperitoneal lymphadenopathy. To our knowledge, this is the first case to be reported in association with inflammatory bowel disease, perhaps providing a novel insight into the pathogenesis of this lesion that has not been considered in the contemporary literature.

Deep Learning-Based Abdominal Muscle Segmentation on CT Images of Surgical Patient Populations

Computed tomography (CT) is commonly used for the characterization and tracking of abdominal muscle mass in surgical patients for both pre-surgical outcome predictions and post-surgical monitoring of response to therapy. In order to accurately track changes of abdominal muscle mass, radiologists must manually segment CT slices of patients, a time-consuming task with potential for variability. In this work, we combined a fully convolutional neural network (CNN) with high levels of preprocessing to improve segmentation quality. We utilized a CNN based approach to remove patients' arms and fat from each slice and then applied a series of registrations with a diverse set of abdominal muscle segmentations to identify a best fit mask. Using this best fit mask, we were able to remove many parts of the abdominal cavity, such as the liver, kidneys, and intestines. This preprocessing was able to achieve a mean Dice similarity coefficient (DSC) of 0.53 on our validation set and 0.50 on our test set by only using traditional computer vision techniques and no artificial intelligence. The preprocessed images were then fed into a similar CNN previously presented in a hybrid computer vision-artificial intelligence approach and was able to achieve a mean DSC of 0.94 on testing data. The preprocessing and deep learning-based method is able to accurately segment and quantify abdominal muscle mass on CT images.

Review of COVID-19, part 1: Abdominal manifestations in adults and multisystem inflammatory syndrome in children

The coronavirus disease 2019 (COVID -19) pandemic caused by the novel severe acute respiratory syndrome coronavirus (SARS-CoV-2) has affected almost every country in the world, resulting in severe morbidity, mortality and economic hardship, and altering the landscape of healthcare forever. Although primarily a pulmonary illness, it can affect multiple organ systems throughout the body, sometimes with devastating complications and long-term sequelae. As we move into the second year of this pandemic, a better understanding of the pathophysiology of the virus and the varied imaging findings of COVID-19 in the involved organs is crucial to better manage this complex multi-organ disease and to help improve overall survival. This manuscript provides a comprehensive overview of the pathophysiology of the virus along with a detailed and systematic imaging review of the extra-thoracic manifestation of COVID-19 with the exception of unique cardiothoracic features associated with multisystem inflammatory syndrome in children (MIS-C). In Part I, extra-thoracic manifestations of COVID-19 in the abdomen in adults and features of MIS-C will be reviewed. In Part II, manifestations of COVID-19 in the musculoskeletal, central nervous and vascular systems will be reviewed.

Current status of deep learning in abdominal image reconstruction

Abdominal magnetic resonance imaging (MRI) and computed tomography (CT) are commonly used for disease screening, diagnosis, and treatment guidance. However, abdominal MRI has disadvantages including slow speed and vulnerability to motions, while CT suffers from problems of radiation. It has been reported that deep learning reconstruction can solve such problems while maintaining good image quality. Recently, deep learning-based image reconstruction has become a hot topic in the field of medical imaging. This study reviews the latest research on deep learning reconstruction in abdominal imaging, including the widely used convolutional neural network, generative adversarial network, and recurrent neural network.

A Systematic Review of Abdominal Imaging Findings in COVID-19 Patients

OBJECTIVE

The objective of this systematic review was to evaluate key imaging manifestations of COVID-19 on abdominal imaging by utilizing a comprehensive review of the published literature.

METHOD

A systematic literature search from PubMed, Google Scholar, and Scopus was performed for studies mentioning abdominal imaging findings in COVID-19 patients. Studies published from inception to 15 March 2021 were included.

RESULTS

A total of 116 studies comprising 1,198 patients were included. Abdominal pain was the most common indication for abdominal imaging in 50.2% of the patients. No abnormality was seen in 48.1% of abdominopelvic computed tomography scans. Segmental bowel wall thickening (14.7%) was the most common imaging abnormality, followed by bowel ischemia (7.1%), solid organ infarction (6.7%), vessel thrombosis (6.7%), and fluid-filled colon (6.2%). Other relevant findings were dilated air-filled bowel, pancreatitis, pneumatosis/portal venous gas, bowel perforation, and appendicitis. Other than abdominal findings, COVID-19-related basal lung changes were incidentally detected in many studies. Moreover, the presence of bowel imaging findings was positively correlated with the clinical severity of COVID-19 infection.

CONCLUSION

This review describes the abdominal imaging findings in COVID-19 patients. This is pertinent for the early diagnosis of COVID-19 in patients presenting solely with abdominal symptoms as well as in identifying abdominal complications in a known case of COVID-19.

RAVE-T2/T1 - Feasibility of a new hybrid MR-sequence for free-breathing abdominal MRI in children and adolescents

BACKGROUND

The new radial volumetric encoding RAVE-T₂/T₁ hybrid sequence is a modern three-dimensional sequence with multiparametric approach, which includes T₂- and T₁-weighted contrasts obtained in identical slice position during one measurement. However, the RAVE-T₂/T₁ hybrid sequence is not yet being used in clinical routine.

PURPOSE

The aim of this study was to evaluate the RAVE-T₂/T₁ hybrid sequence in a pediatric population with a clinical indication for an abdominal MRI examination to demonstrate that the hybrid imaging may be less challenging to perform on children.

MATERIALS AND METHODS

Our retrospective observational study included pediatric patients of all age groups and required for an abdominal MRI examination. Non-contrast standard axial T₁ DIXON and non-contrast RAVE-T₂/T₁ hybrid sequence were obtained at 3 T. MRI studies were analyzed independently by two pediatric radiologists using a 5-point Likert-type scale in five different categories. T₁- and T₂-weighted sequences were each compared with the RAVE-T₂/T₁-sequence using a Wilcoxon signed-rank test.

RESULTS

The analysis included 15 children (mean age, 11 years and 4 months, 7 girls and 8 boys). The Cohens Kappa of interrater agreement measured 0.62. The T₂ weighted part of the RAVE-T₂/T₁ sequence was significantly better than the standard T₂ HASTE sequence in four of five image quality categories: overall image quality (2.2 ± 0.7 vs 1.8 ± 0,7, p = 0.03), respiratory motion artefacts (3.8 ± 0.4 vs 2.0 ± 0.7, p <= 0.01), portal vein clarity (3.3 ± 0.8 vs 2.2 ± 0.7, p <= 0.01), hepatic margin sharpness (2.4 ± 1,0 vs 1.8 ± 0.7, p <= 0.01). The T₁ weighted part of the RAVE-T₂/T₁ sequence was significantly better than the standard T₁ DIXON weighted sequence in three of five image quality categories: respiratory motion artefacts (4.0 ± 0.2 vs 3.6 ± 0.8, p = 0.01), portal vein clarity (2.7 ± 0.9 vs 2.1 ± 0.7, p <= 0.01), hepatic margin sharpness (3.2 ± 0.7 vs 2.6 ± 0.9, p <= 0.01).

CONCLUSIONS

The RAVE-T₂/T₁ hybrid sequence is feasible and equal compared to standard T₁- and T₂-weighted sequences in the assessment of abdominal organs in a pediatric population. Due to non-inferiority to the current standard sequences for abdominal imaging, the RAVE-T₂/T₁ hybrid sequence is a good alternative for children who cannot be examined in breath-hold technique.

Ultrasound for Suspected Acute Appendicitis in Adult Women Under Age 40: An Evaluation of On-Call Radiology Resident Scanning

RATIONALE AND OBJECTIVES

At our institution, on-call radiology residents perform emergent ultrasounds (US) outside of departmental working hours. The aim of the study was to evaluate radiology resident-performed US for clinically suspected acute appendicitis in women under the age of 40.

MATERIALS AND METHODS

Retrospective review of 104 consecutive US scans outside of departmental working hours by radiology residents, and 104 consecutive US studies scanned during departmental working hours by sonographers, in women under the age of 40 for clinically suspected appendicitis .

RESULTS

Appendix visualization rate was 27% for the resident group (sonographer group: 30%, p = 0.759). The sensitivity and specificity of US for appendicitis were 63% (95% confidence interval: 41%-81%) and 98% (95% CI: 91%-100%), respectively for the resident group (sonographer group: 69% [95% CI: 41%-89 %] and 98% [95% CI: 92%-100%], respectively). An alternative cause for right lower quadrant pain was offered in 17% of resident group cases (sonographer group: 21%, p = 0.598). Follow-up CT or MRI was performed in 47% of resident cases (sonographer group: 44%, p = 0.781). Residents performed more focused US (i.e. not imaging the pelvic organs), at 34% (sonographer group: 1%, p < 0.001). When only focused scanning was performed by residents, there was a trend toward increased downstream imaging (CT or MRI), odds ratio = 2.76 (95% CI: 0.99-7.70).

CONCLUSIONS

Out-of-hours US scans performed by radiology residents had similar performance characteristics compared to departmental sonographers. We discovered an increased rate of downstream imaging in cases in which residents performed limited scans and did not document visualization of the pelvic organs.

COVID-19 and the digestive system: A comprehensive review

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is spreading at an alarming rate, and it has created an unprecedented health emergency threatening tens of millions of people worldwide. Previous studies have indicated that SARS-CoV-2 ribonucleic acid could be detected in the feces of patients even after smear-negative respiratory samples. However, demonstration of confirmed fecal-oral transmission has been difficult. Clinical studies have shown an incidence rate of gastrointestinal (GI) symptoms ranging from 2% to 79.1% in patients with COVID-19. They may precede or accompany respiratory symptoms. The most common GI symptoms included nausea, diarrhea, and abdominal pain. In addition, some patients also had liver injury, pancreatic damage, and even acute mesenteric ischemia/thrombosis. Although the incidence rates reported in different centers were quite different, the digestive system was the clinical component of the COVID-19 section. Studies have shown that angiotensin-converting enzyme 2, the receptor of SARS-CoV-2, was not only expressed in the lungs, but also in the upper esophagus, small intestine, liver, and colon. The possible mechanism of GI symptoms in COVID-19 patients may include direct viral invasion into target cells, dysregulation of angiotensin-converting enzyme 2, immune-mediated tissue injury, and gut dysbiosis caused by microbiota. Additionally, numerous experiences, guidelines, recommendations, and position statements were published or released by different organizations and societies worldwide to optimize the management practice of outpatients, inpatients, and endoscopy in the era of COVID-19. In this review, based on our previous work and relevant literature, we mainly discuss potential fecal-oral transmission, GI manifestations, abdominal imaging findings, relevant pathophysiological mechanisms, and infection control and prevention measures in the time of COVID-19.

TB or not TB: A comprehensive review of imaging manifestations of abdominal tuberculosis and its mimics

The ever-growing prevalence of tuberculosis is a cause for concern among both developing and developed countries. Abdominal tuberculosis is the most common site of extrapulmonary tuberculosis and involves almost all of the visceral organs. Clinical presentation of abdominal tuberculosis is often non-specific. Thus, having a high index of clinical suspicion is necessary to aide early diagnosis and guide prompt initiation of appropriate treatment. In this review, we focus on the entire spectrum of abdominal tuberculosis and other diseases mimicking it with an emphasis on their imaging findings.

Generative multi-adversarial network for striking the right balance in abdominal image segmentation

Purpose The identification of abnormalities that are relatively rare within otherwise normal anatomy is a major challenge for deep learning in the semantic segmentation of medical images. The small number of samples of the minority classes in the training data makes the learning of optimal classification challenging, while the more frequently occurring samples of the majority class hamper the generalization of the classification boundary between infrequently occurring target objects and classes. In this paper, we developed a novel generative multi-adversarial network, called Ensemble-GAN, for mitigating this class imbalance problem in the semantic segmentation of abdominal images.Method The Ensemble-GAN framework is composed of a single-generator and a multi-discriminator variant for handling the class imbalance problem to provide a better generalization than existing approaches. The ensemble model aggregates the estimates of multiple models by training from different initializations and losses from various subsets of the training data. The single generator network analyzes the input image as a condition to predict a corresponding semantic segmentation image by use of feedback from the ensemble of discriminator networks. To evaluate the framework, we trained our framework on two public datasets, with different imbalance ratios and imaging modalities: the Chaos 2019 and the LiTS 2017.Result In terms of the F1 score, the accuracies of the semantic segmentation of healthy spleen, liver, and left and right kidneys were 0.93, 0.96, 0.90 and 0.94, respectively. The overall F1 scores for simultaneous segmentation of the lesions and liver were 0.83 and 0.94, respectively.Conclusion The proposed Ensemble-GAN framework demonstrated outstanding performance in the semantic segmentation of medical images in comparison with other approaches on popular abdominal imaging benchmarks. The Ensemble-GAN has the potential to segment abdominal images more accurately than human experts.

Single source split filter dual energy: Image quality and liver lesion detection in abdominal CT

PURPOSE

Aim of this study was to evaluate image quality of single source dual energy CT (SSDE-CT) using split filter technique in oncologic abdominal CT.

METHOD

51 consecutive patients with newly diagnosed breast carcinoma were prospectively enrolled in this study and underwent a staging examination of the abdomen using SSDE-CT (120 kV, split filter technique, 400 ref. mAs). Inline default images (DI) and post-processed virtual monoenergetic images at 40 keV, 50 keV, 60 keV, 70 keV and 80 keV were reconstructed. Objective image quality was evaluated as contrast to noise ratio (CNR) for liver parenchyma, portal vein, spleen, pancreas, aorta and hypoattenuating liver lesions. Subjective image quality was rated on a 5-point scale. Image quality at different keV settings was analyzed in paired t-tests.

RESULTS

CNR was highest at 40 keV for vessels (portal vein: 9.0, aorta: 8.8, all p < 0.001) and for upper abdominal organs (spleen: 4.8, all p < 0.001; pancreas: 2.7, all p < 0.01 except p = 0.93 for 50 keV; liver parenchyma: 3.4, all p < 0.01). Highest CNR values for hypoattenuating liver lesions were found at 40 keV (7.7, all p < 0.001). Overall subjective image quality was highest with 80 keV and DI (both 4.8, all p < 0.001). Artifacts were most pronounced at 40 keV.

CONCLUSIONS

High image quality can be obtained with SSDE-CT of the abdomen. Lowest monoenergetic reconstructions provide the highest image contrast and should be used for vessel evaluation. The best trade-off between artifacts and parenchymal contrast can be obtained with 80 keV images.

Torso injuries after fall from standing-empiric abdominal or thoracic CT imaging is not indicated

PURPOSE

Falls from standing (FFS) have become the most common mechanism of injury at many trauma centers. Liberal imaging of low energy trauma has questionable value. We hypothesize that torso trauma intervention is rare in the FFS population, and physical examination sufficiently screens for torso injuries needing intervention.

METHODS

We queried our ACS-verified Level 1 trauma center registry for falls from standing from 1/1/14 to 12/31/16. Exclusion criteria were: falls from height, falls associated with penetrating trauma, lack of an abdominal or chest CT, a Glasgow Coma Scale Score (GCS) less than 15, and surgical intervention at another facility prior to arrival at our center. Demographics, historical details, hemodynamics, injuries, injury severity, procedures, initial vital signs, and outcome were recorded.

RESULTS

1,654 patients had a FFS during our study period. 728 had an abdominal or chest CT and a GCS of 15 and comprised the evaluable population. Mean age was 56.5 years. 55.8% were female. The mortality rate was 8%. There were 179 chest injuries in 121 patients, and 54 abdominal injuries in 43 patients. 379 patients had a GCS of 15 and underwent thoracic CT, yet only 11 (3%) underwent intervention. The negative predictive value for physical exam was 100% for chest intervention. 349 patients had a GCS of 15 and abdominal CT, yet only 13 (3.7%) underwent procedural intervention. Abdominal physical exam had a negative predictive value of 99.7% for intervention, but when combined with vital signs, the value was 100%.

CONCLUSION

Torso injuries in FFS are rare. Of our study population, 13 abdominal injuries underwent intervention, and 11 chest injuries underwent intervention. Screening patients by physical examination and vital signs is sufficient and safely allows for the use of selective abdominal and chest CT.

Teratoma involving adrenal gland - A case report and review of literature

Teratomas are germ cell tumors which are mainly gonadal in origin. Other common extra-gonadal sites are mediastinal, sacro-coccygeal and pineal regions. Adrenal teratomas are extremely rare and primary adrenal teratomas are even rarer. We reported a case of primary adrenal teratoma in a 60-year-old male. We reviewed literature from 2000 to till date, and found 29 adult cases and 6 paediatric cases of adrenal teratoma. Usually, they are asymptomatic and identified as an incidental finding. Imaging modality such as USG, CT and MRI are useful in diagnosis. Though these tumors are mostly benign, malignant transformation may occur. Treatment includes surgical removal.

Implementation of patient-tailored contrast volumes based on body surface area and heart rate harmonizes contrast enhancement and reduces contrast load in small patients in portal venous phase abdominal CT

PURPOSE

The aim of this study was to evaluate the impact of a patient-tailored contrast volume protocol on portal venous phase abdominal CT-images compared to a fixed volume protocol in daily radiological practice.

METHOD

Data of 77 patients who underwent two contrast-enhanced CT-examinations were collected. The first examination was performed with a fixed contrast volume (95 ml), the follow-up examination was performed with a patient-tailored contrast volume based on patient's BSA and heart rate. The patient-tailored volume was calculated by a software application integrated in the interface of the injection pump. Two independent radiologists assessed subjective and objective image quality. Differences in enhancement and contrast volumes between both protocols were analysed.

RESULTS

Despite a significant contrast volume reduction in women and in patients with low to normal BMI, enhancement was more consistent over different BMI-categories in the patient-tailored contrast volume protocol and there was no significant difference in subjective image quality between both injection protocols.

CONCLUSIONS

A patient-tailored contrast volume protocol based on BSA and heart rate can be considered in daily radiological practice to decrease contrast volumes in women and in low to normal BMI patients and to achieve more consistent contrast enhancement across different BMI-categories in venous phase abdominal CT.

Comparison of image noise and image quality between full-dose abdominal computed tomography scans reconstructed with weighted filtered back projection and half-dose scans reconstructed with improved sinogram-affirmed iterative reconstruction (SAFIRE*)

PURPOSE

To retrospectively compare the image noise, signal-to-noise ratio (SNR), and subjective image quality between CT images acquired with a dual-source, split-dose imaging protocol reconstructed at full and half doses with weighted filtered back projection (wFBP) and an improved sinogram-affirmed iterative reconstruction algorithm (SAFIRE*).

METHODS

Fifty-three consecutive patients underwent contrast-enhanced CT of the abdomen using a standardized dual-source, single energy CT protocol. Half-dose images were retrospectively generated using data from one detector only. Full-dose datasets were reconstructed with wFBP, while half-dose datasets were reconstructed with wFBP and SAFIRE* strengths 1-5. Region of interest analysis was performed to assess SNR and noise. Diagnostic acceptability, subjective noise, and spatial resolution were graded on a 10-point scale by two readers. Statistical analysis was carried out with repeated measures analysis of variance, Wilcoxon signed rank test, and Cohen's κ test.

RESULTS

With the increasing strengths of SAFIRE*, a progressive reduction in noise and increase in SNR (p < 0.01) was observed. There was a statistically significant decrease in objective noise and increase in SNR in half-dose SAFIRE* strength 4 and 5 reconstructions compared to full-dose reconstructions using wFBP (p < 0.01). Qualitative analysis revealed a progressive increase in diagnostic acceptability, decrease in subjective noise and increase in spatial resolution for half-dose images reconstructed with the increasing strengths of SAFIRE* (p < 0.01).

CONCLUSIONS

Half-dose CT images reconstructed with SAFIRE* at strength 4 and 5 have superior image quality compared to full-dose images reconstructed with wFBP. SAFIRE* potentially allows dose reductions in the order of 50% over wFBP.

Review of the role of abdominal imaging in irritable bowel syndrome

The role of radiologic imaging in the investigation of irritable bowel syndrome (IBS) remains a subject of debate and there is some evidence, from recent studies of utilization of imaging in IBS, which focused on associated costs and radiation exposure, that imaging is being used relatively widely in these patients. This review aims to assess current best evidence to accurately define the role of radiologic imaging in IBS patients. Primary and secondary literature searches were performed. Evidence suggests that the lack of "red flag" or alarm features in IBS patients should reassure the clinician that the diagnosis of IBS is correct and United States and United Kingdom guidelines recommend no radiologic imaging for IBS patients if alarm features are not present. In patients presenting with IBS symptoms and alarm features, radiologic testing may be used to exclude an alternative diagnosis and the imaging modality should be chosen based on the most likely alternative diagnosis.

Classification of Error in Abdominal Imaging: Pearls and Pitfalls for Radiologists

Peer review for radiologists plays an important role in identifying contributing factors that can lead to diagnostic errors and patient harm. It is essential that all radiologists be aware of the multifactorial causes of diagnostic error in radiology and the methods available to reduce it. This pictorial review provides readers with an overview of common errors that occur in abdominal radiology and strategies to reduce them. This review aims to make readers more aware of pitfalls in abdominal imaging so that these errors can be avoided in the future. This essay also provides a systematic approach to classifying abdominal imaging errors that will be of value to all radiologists participating in peer review.

Principles of three-dimensional printing and clinical applications within the abdomen and pelvis

Improvements in technology and reduction in costs have led to widespread interest in three-dimensional (3D) printing. 3D-printed anatomical models contribute to personalized medicine, surgical planning, and education across medical specialties, and these models are rapidly changing the landscape of clinical practice. A physical object that can be held in one's hands allows for significant advantages over standard two-dimensional (2D) or even 3D computer-based virtual models. Radiologists have the potential to play a significant role as consultants and educators across all specialties by providing 3D-printed models that enhance clinical care. This article reviews the basics of 3D printing, including how models are created from imaging data, clinical applications of 3D printing within the abdomen and pelvis, implications for education and training, limitations, and future directions.

Acute appendicitis: Factors associated with inconclusive ultrasound study and the need for additional computed tomography

PURPOSE

To identify variables associated with inconclusive ultrasound examination and the need for further abdominopelvic computed tomography (CT) examination for the diagnosis of acute appendicitis.

MATERIALS AND METHODS

A total of 105 adult patients with acute appendicitis were included. There were 55 patients (38 men, 17 women; mean age, 23±9 [SD] years; range: 15-58 years) with a diagnosis of acute appendicitis using ultrasound alone and 50 patients (30 men, 20 women; mean age, 31±14 [SD] years; range: 16-83 years) who required further CT. Demographic, clinical, and biological criteria and appendix location were compared between the two groups to search for variables associated with the need of further CT.

RESULTS

Patients who required further CT were older (31.1±14 [SD] years) and had a greater body mass index (BMI) (26.7±4.3 [SD]kg/m²) than those who did not require CT (23±9 [SD] years and 22.9±3.4 [SD]kg/m²), respectively (P<0.01). A greater proportion of patients with complicated acute appendicitis was observed in patients who required further CT (9/50; 18%) than in those who had only ultrasound (1/55; 2%) (P=0.012). Atypical appendix location was more frequent in patients who required CT (19/50; 36%) than in those who had only ultrasound (6/55; 11%) (P<0.001). There were no significant differences regarding gender, inflammatory syndrome and hours of imaging (on call vs. working hours) between the two groups.

CONCLUSION

Advanced age, high BMI, atypical appendix location, and complicated appendicitis are associated with inconclusive ultrasound and the need for further CT to diagnose acute appendicitis.

Pearls, Pitfalls, and Problems in Dual-Energy Computed Tomography Imaging of the Body

Dual-energy computed tomography (DECT) is an exciting technology that is increasing in routine use and has the potential for significant clinical impact. With the advancement of DECT, it is important for radiologists to be aware of potential challenges with DECT acquisition and postprocessing, and to have a basic knowledge of unique artifacts and diagnostic pitfalls that can occur when interpreting DECT scans and DECT postprocessed images. This article serves as a practical overview of potential problems and diagnostic pitfalls associated with DECT, and steps that can be taken to avoid them.

Added value of diffusion-weighted imaging in hepatic tumors and its impact on patient management

Background

To investigate the added diagnostic value of diffusion-weighted imaging (DWI) of the liver and its impact on therapy decisions in patients with hepatic malignancy.

Methods

Interdisciplinary gastrointestinal tumorboard cases concerning patients with hepatic malignancies discussed between 11/2015 and 06/2016 were included in this retrospective, single-center study. Two radiologists independently reviewed the respective liver MR-examination first without, then with DWI. The readers were blinded regarding number, position and size of hepatic malignancies. Cases in which DWI revealed additional findings concerning the hepatic tumor status as compared to conventional sequences alone were presented to experienced members of the interdisciplinary tumor board. In this retrospective setting changes in treatment decisions based on these additional findings in the DWI sequences were recorded.

Results

A total of 87 patients were included. DWI revealed additional findings in 12 patients (13,8%). These new findings had a direct effect on the therapy in 8 patients (9,2%): In 6 patients (6,9%) the surgical/interventional treatment was adapted (n = 5: extended resection, n = 1: with transarterial chemoembolization of a single hepatocellular carcinoma only detectable in DWI); 2 patients (2,3%) received systemic therapy (n = 1: neo-adjuvant, n = 1: palliative) based on the additional findings in DWI. In 4 patients (4.6%) additional DWI findings did not affect the therapeutic decision.

Conclusions

DWI is a relevant diagnostic tool in oncologic imaging of the liver. By providing further information regarding tumor load in hepatic malignancies it can lead to a significant change in treatment.

Documentation, coding, and billing: what abdominal radiologists need to know

This article reviews basic concepts of report documentation for abdominal imaging examinations, focusing on practical elements for ensuring appropriate physician reimbursement. Nuances of abdominal radiography, CT, MRI, and ultrasonography codes are highlighted. Special considerations for the coding of 3D-rendering and contrast administration are also described. Greater abdominal radiologist awareness of these codes and their reporting requirements can help ensure proper documentation within radiology reports, thereby optimizing legitimate reimbursement.

Evaluation of Large-Aperture Imaging Through the ex Vivo Human Abdominal Wall

Current clinical abdominal imaging arrays are designed to maximize angular field of view rather than the extent of the coherent aperture. We illustrate, in ex vivo experiments, the use of a large effective aperture to perform high-resolution imaging, even in the presence of abdominal wall-induced acoustic clutter and aberration. Point and lesion phantom targets were imaged through a water path and through three excised cadaver abdominal walls to create different clinically relevant clutter effects with matched imaging targets. A 7.36-cm effective aperture was used to image the targets at a depth of 6.4 cm, and image quality metrics were measured over a range of aperture sizes using synthetic aperture techniques. In all three cases, although degradation compared with the control was observed, lateral resolution improved with increasing aperture size without loss of contrast. Spatial compounding of the large-aperture data drastically improved lesion detectability and produced contrast-to-noise ratio improvements of 83%-106% compared with the large coherent aperture. These studies indicate the need for the development of large arrays for high-resolution abdominal diagnostic imaging.

Utilization of virtual mono-energetic images (MonoE) derived from a dual-layer spectral detector CT (SDCT) for the assessment of abdominal arteries in venous contrast phase scans

OBJECTIVES

To investigate the utilization of virtual mono-energetic images (MonoE) at low kiloelectron volt (keV) levels derived from a dual-layer spectral detector CT (SDCT) for the assessment of abdominal arteries in venous contrast phase scans using arterial phase imaging as an internal reference standard.

MATERIALS AND METHODS

A total of 50 patients who received arterial and venous phase imaging of the abdomen on a SDCT system were included in this study. Absolute attenuation, noise, signal- and contrast to noise ratios (SNR; CNR) as well as arterial diameters in defined landmarks were assessed. In arterial phase, conventional reconstructions (CR_ART) as well as MonoE_ART at 40keV and in venous phase, conventional reconstructions (CR_VEN) as well as MonoE_VEN at 70 and 40keV were investigated and intra-individual comparisons were performed. If an artery stenosis (10 patients) was present, the degree of stenosis was assessed according to the system of the North American Symptomatic Carotid Endarterectomy Trial (NASCET).

RESULTS

MonoE 40keV yielded significantly higher attenuation values (in arterial as well as in venous phase) compared to CR_ART (p<0.001) while noise levels were substantially low. This resulted in markedly superior SNR and CNR in large vessel compared to CR_ART. Luminal diameters were significantly smaller in MonoE 40keV in both contrast phases compared to CR_ART (p<0.001), whereas no significant differences were found between both MonoE reconstructions (p≥0.92). The degree of vessel stenosis was significantly higher in MonoE 40keV of both contrast phases compared to CR_ART (p≥0.02).

CONCLUSION

MonoE at low keV of venous contrast phase scans derived from a novel SDCT are suitable for the assessment of arteries in the abdomen and subsequent stenosis assessment. However, MonoE at 40keV constantly showed significant smaller luminal diameters than the corresponding conventional reconstructions (including the reference standard). This is possibly due to an improved differentiation of the vessel lumen from the wall and raises the question, which imaging technique should be used as an appropriate reference standard for vascular SDCT imaging studies.

Radiology report "disclaimers" increase the use of abdominal CT in the work-up of pediatric abdominal pain

OBJECTIVE

Pediatric abdominal pain is commonly evaluated in the emergency department (ED) initially by ultrasonography (U/S). Radiology reports often include commentary about U/S limitations and possible need for additional testing or evaluation independent of study interpretation. We sought to determine if presence of a "disclaimer" is associated with additional imaging.

METHODS

Design: Retrospective cohort.

SETTING

Community ED with volume of 85,000 annual visits.

POPULATION

Consecutive ED patients <21-years-old with appendix U/S over 12-months. Radiologist reports were assessed for disclaimers and if definitive diagnoses of appendicitis were made. The incidence of subsequent CT imaging was determined and group differences between categories were calculated.

RESULTS

441 eligible patients were identified with average age 11.7years. Of all U/S studies, 26% were definitive for appendicitis and 74% were non-definitive. Disclaimers were included on 60% of all studies, including 13% of definitive studies and 76% of non-definitive studies. 25% of all studies including a disclaimer had follow-up CT versus 10% of studies without a disclaimer (15% difference; 95% CI: 9-21). For patients with definitive interpretations, 6% had follow-up CT with no significant difference between groups with or without a disclaimer. For patients with non-definitive studies, 26% with a disclaimer had follow-up CT scans versus 13% without a disclaimer (13% difference; 95% CI: 4-22).

CONCLUSIONS

Appendix ultrasound interpretations often include a disclaimer, which leads to a 150% increase in follow-up CT imaging. We suggest that radiologists consider the impact of including such a disclaimer, knowing that this may contribute to possible unnecessary imaging.

Abdominal imaging ordering patterns by referring provider specialty

PURPOSE

Prior work has demonstrated marked growth in the volume of abdominal imaging performed by radiologists. However, decisions to pursue imaging are largely driven by referring providers. In this study, we take the novel approach of investigating abdominal imaging utilization patterns by referring provider specialty.

METHODS

Data on imaging services were obtained from the 2014 DocGraph Medicare Referring Provider Utilization for Procedures (MrPUP) public use file. MrPUP contains aggregated transaction data for combinations of unique referring provider and service code. Imaging services were classified by modality and body region using the Neiman Institute Types of Service (NITOS). Each referring provider's specialty was determined using Medicare Physician Compare. Abdominal imaging ordering patterns were summarized by referring specialty.

RESULTS

The final dataset included 5,824,754 abdominal imaging transactions. The most common ordering specialties of abdominal imaging were as follows: (1) internal medicine; (2) urology; (3) emergency medicine; (4) family practice; and (5) gastroenterology. The most common ordering specialties by abdominal imaging modality were emergency medicine for CT; gastroenterology for MRI and nuclear medicine; and internal medicine for ultrasound and radiography. While numerous specialties commonly ordered abdominal radiography and CT, urologists also commonly ordered retroperitoneal ultrasound and retrograde urography, and gastroenterologists also commonly ordered abdominal ultrasound, abdominal MRI, and esophagrams. Internal medicine, family practice, and emergency medicine providers ordered a much broader mix of imaging, including many non-abdominal imaging examinations.

CONCLUSION

Referring specialty abdominal imaging ordering patterns are varied but distinct. Awareness of these patterns may facilitate focused educational and policy initiatives to improve abdominal imaging appropriateness and utilization.