Machine Learning Detection and Characterization of Splenic Injuries on Abdominal Computed Tomography.

BACKGROUND: Multi-detector contrast-enhanced abdominal computed tomography (CT) allows for the accurate detection and classification of traumatic splenic injuries, leading to improved patient management. Their effective use requires rapid study interpretation, which can be a challenge on busy emergency radiology services. A machine learning system has the potential to automate the process, potentially leading to a faster clinical response. This study aimed to create such a system. METHOD: Using the American Association for the Surgery of Trauma (AAST), spleen injuries were classified into 3 classes: normal, low-grade (AAST grade I-III) injuries, and high-grade (AAST grade IV and V) injuries. Employing a 2-stage machine learning strategy, spleens were initially segmented from input CT images and subsequently underwent classification via a 3D dense convolutional neural network (DenseNet). RESULTS: This single-centre retrospective study involved trauma protocol CT scans performed between January 1, 2005, and July 31, 2021, totaling 608 scans with splenic injuries and 608 without. Five board-certified fellowship-trained abdominal radiologists utilizing the AAST injury scoring scale established ground truth labels. The model achieved AUC values of 0.84, 0.69, and 0.90 for normal, low-grade injuries, and high-grade splenic injuries, respectively. CONCLUSIONS: Our findings demonstrate the feasibility of automating spleen injury detection using our method with potential applications in improving patient care through radiologist worklist prioritization and injury stratification. Future endeavours should concentrate on further enhancing and optimizing our approach and testing its use in a real-world clinical environment.

Interrater Agreement of CT Grading of Blunt Splenic Injuries: Does the AAST Grading Need to Be Reimagined?

Introduction: The Revised Organ Injury Scale (OIS) of the American Association for Surgery of Trauma (AAST) is the most widely accepted classification of splenic trauma. The objective of this study was to evaluate inter-rater agreement for CT grading of blunt splenic injuries. Methods: CT scans in adult patients with splenic injuries at a level 1 trauma centre were independently graded by 5 fellowship trained abdominal radiologists using the AAST OIS for splenic injuries - 2018 revision. The inter-rater agreement for AAST CT injury score, as well as low-grade (IIII) versus high-grade (IV-V) splenic injury was assessed. Disagreement in two key clinical scenarios (no injury versus injury, and high versus low grade) were qualitatively reviewed to identify possible sources of disagreement. Results: A total of 610 examinations were included. The inter-rater absolute agreement was low (Fleiss kappa statistic 0.38, P < 0.001), but improved when comparing agreement between low and high grade injuries (Fleiss kappa statistic of 0.77, P < .001). There were 34 cases (5.6%) of minimum two-rater disagreement about no injury vs injury (AAST grade ≥ I). There were 46 cases (7.5%) of minimum two-rater disagreement of low grade (AAST grade I-III) versus high grade (AAST grade IV-V) injuries. Likely sources of disagreement were interpretation of clefts versus lacerations, peri-splenic fluid versus subcapsular hematoma, application of adding multiple low grade injuries to higher grade injuries, and identification of subtle vascular injuries. Conclusion: There is low absolute agreement in grading of splenic injuries using the existing AAST OIS for splenic injuries.

Evaluation of Adjuvant Chemotherapy-Associated Steatosis (CAS) in Colorectal Cancer.

Chemotherapy-associated steatosis is poorly understood in the context of colorectal cancer. In this study, Stage II-III colorectal cancer patients were retrospectively selected to evaluate the frequency of chemotherapy-associated steatosis and to determine whether patients on statins throughout adjuvant chemotherapy develop chemotherapy-associated steatosis at a lower frequency. Baseline and incident steatosis for up to one year from chemotherapy start date was assessed based on radiology. Of 269 patients, 76 (28.3%) had steatosis at baseline. Of the remaining 193 cases, patients receiving adjuvant chemotherapy (n = 135) had 1.57 (95% confidence interval [CI], 0.89 to 2.79) times the adjusted risk of developing steatosis compared to patients not receiving chemotherapy (n = 58). Among patients who underwent chemotherapy, those using statins for pre-existing hyperlipidemia (n = 37) had 0.71 (95% CI, 0.10 to 2.75) times the risk of developing steatosis compared to patients who were not prevalent users of statins (n = 98). Chemotherapeutic treatment of Stage II-III colorectal cancer appears to be consistent with a moderately increased risk of steatosis, although larger studies are necessary to assess the significance of this observation. Prospective trials should be considered to further explore the potential for protective use of statins in this curative patient population.

Predictive Value of Single or Combined Ultrasound Signs in the Diagnosis of Ovarian Torsion.

OBJECTIVES: To determine predictive values of isolated and combined ultrasound signs in the diagnosis of adnexal torsion. METHODS: This work was a retrospective study of 129 adult female patients who underwent an ultrasound examination followed by a definitive surgical procedure within a 24-hour period to determine whether adnexal torsion was present. RESULTS: The positive predictive value (PPV) of the ultrasound diagnosis of adnexal torsion was 82.2%. The statistically significant ultrasound signs in multivariate logistic regression with single-predictor analyses were relative enlargement of the ovary, an abnormal adnexal position, a twisted vascular pedicle, and the follicular edema "ring sign." Possible combinations of these ultrasound criteria showed high specificities (74%-100%), high PPVs (93%-100%), and lower sensitivities (29%-71%) and negative predictive values (24%-35%). Any combination that included a twisted vascular pedicle or the follicular ring sign as one of the signs had high odds ratios and positive likelihood ratios. CONCLUSIONS: Ultrasound has a high PPV as a first-choice imaging modality in the diagnosis of adnexal torsion. The combinations of the following 4 statistically significant ultrasound signs, consisting of an abnormal position, relative enlargement of the index ovary, a twisted vascular pedicle, and the follicular edema ring sign, substantially narrow the imaging differential diagnosis in such cases. The presence of vascular pedicle twisting and the follicular ring sign was highly associated with a positive ovarian torsion diagnosis, with 100% specificity.

Diagnostic Value of CT in Detecting Peripheral Zone Prostate Cancer.

OBJECTIVE. The purpose of this study was to identify the sensitivity of contrast-enhanced CT in detecting high-grade prostate adenocarcinoma. MATERIALS AND METHODS. A retrospective analysis included 100 patients with prostate cancer proven by biopsy between January 2010 and December 2017 who underwent staging CT of the abdomen and pelvis within 3 months of diagnosis. The control subjects were 100 randomly selected aged-matched male outpatients with no known history of malignancy who underwent contrast-enhanced CT of the abdomen and pelvis in the same time period as the patients with cancer. Two readers, blinded to both groups, independently assessed the likelihood of prostate cancer on the basis of the CT finding of focal abnormally increased peripheral enhancement in the prostate. Binary classification of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) was used to assess the diagnostic utility of CT versus the reference standard of transrectal ultrasound-guided biopsy. RESULTS. Eighty-three of 100 patients with biopsy-proven prostate cancer and 92 of 100 control subjects were correctly identified (sensitivity, 0.83; specificity, 0.92; PPV, 0.91; NPV, 0.84). There was no significant difference in diagnostic accuracy among subjects with different Gleason scores. Interrater agreement on both the cancer and control patients was 0.76 as assessed by Cohen kappa statistic. CONCLUSION. Incidental detection of a focal area of increased enhancement in the periphery of the prostate at contrast-enhanced CT may represent a clinically significant cancer and deserves further workup with prostate-specific antigen measurement and correlation with clinical risk factors for prostate cancer.

Focused CT for the evaluation of suspected appendicitis.

PURPOSE: To determine the diagnostic accuracy of focused appendiceal CT as a feasible alternative to the standard CT of the abdomen and pelvis (CT-AP) in patients with suspected acute appendicitis. METHODS: Retrospective review of 200 adults with suspected acute appendicitis between January and October 2016 were included in this study. Each patient underwent CT-AP with oral and intravenous (IV) contrast. A subset of axial images starting at the top of L4 vertebral body to the roof of the acetabula were obtained from each study which served as the focused appendiceal CT. After review of the focused CTs, the non-focused CT-AP scans were reviewed, each patient acting as their own control. Images were assessed for ability to identify the appendix, assess for appendicitis, or identify alternative diagnoses that could account for the presenting symptoms. RESULTS: Of 200 cases, the appendix was visualized in the focused CT in 191 patients. In nine studies, the appendix was not visualized in focused or standard CT-AP. Using focused CT, 42 cases were positive for acute appendicitis. This result was identical when reviewing standard CT-AP. Alternative diagnoses were present in 38 patients. Using focused CT, 14 of these were not fully covered but the readers were able to make the diagnoses confidently on the focused CTs. Only one patient had acute non-appendiceal pathology mostly outside of the field of view. CONCLUSIONS: Focused appendiceal CT with IV and oral contrast in the setting of clinically suspected appendicitis is a suitable alternative to conventional CT-AP.

Case 263: Malaysian Charm Needles (Susuk).

History A 58-year-old woman was seen in the rheumatology clinic for bilateral wrist and knee pain that was unresponsive to physiotherapy and intra-articular steroid injections. Remote fracture of the left tibia from a motor vehicle collision was reported and was previously treated with conservative management. Serologic work-up for inflammatory disease was negative. The patient reported no prior surgical or medical history. Social history revealed remote immigration from Malaysia. Radiographs of the hands and knees were obtained.

IgG4-related intracranial disease.

IgG4-related disease (IgG4-RD) is a multi-organ chronic inflammatory process caused by infiltration of IgG4-positive plasma cells in one or more organs. Intracranial involvement has only recently become better recognized. Our case series adds to the growing literature on the varying presentations of intracranial IgG4 by describing the clinical and imaging findings of three patients who presented to our institution with intracranial involvement. Our first patient presented with a mass-forming IgG4 pachymeningitis mimicking a sphenoid wing meningioma, which is to our knowledge the largest mass-forming pachymeningitis published in the literature. Our second case depicts another presentation of extensive IgG4 pachymeningitis involving both cavernous sinuses and surrounding Meckel's caves. The third case describes a patient with presumed lymphocytic hypophysitis, which was later determined to be IgG4-related hypophysitis with concomitant pachymeningitis and perineural spread along the optic nerves. The delayed diagnoses in our cases illustrates the diagnostic challenge that clinicians face in differentiating intracranial IgG4-RD from other infiltrative diseases such as sarcoidosis, granulomatous disease, tuberculosis and lymphoma. Earlier consideration of IgG4-related hypophysitis and hypertrophic pachymeningitis in the differential diagnosis can prevent significant morbidity including unnecessary surgical intervention and organ failure secondary to extensive fibrosis.

Case 263.

History A 58-year-old woman was seen in the rheumatology clinic for bilateral wrist and knee pain that was unresponsive to physiotherapy and intra-articular steroid injections. Remote fracture of the left tibia from a motor vehicle collision was reported and was previously treated with conservative management. Serologic work-up for inflammatory disease was negative. The patient reported no prior surgical or medical history. Social history revealed remote immigration from Malaysia. Radiographs of the hands and knees were obtained ( Figs 1 - 4 ). [Figure: see text][Figure: see text][Figure: see text][Figure: see text].

Computed tomography identified factors that preclude living kidney donation.

INTRODUCTION: The purpose of this study was to determine the variety and prevalence of renal and non-renal abnormalities detected on multidetector computed tomography (MDCT) that precluded patients from donating a kidney. METHODS: Institutional review board approval was obtained and the requirement for informed consent was waived. A retrospective, single-centre review of 701 patients (444 female, 257 male; age range 18-86 years; mean age 43.2±11.9 years) that underwent renal donor protocol MDCT was conducted. A systematic review of the CT report, records from multidisciplinary renal transplantation rounds, and electronic medical records was performed to determine which patients were approved or declined as live renal donors. If declined as a donor, CT-identified reasons were categorized as abnormalities of renal vasculature, renal parenchyma, collecting system, or extra-renal. RESULTS: A total of 81 patients were excluded as renal donors on the basis of CT findings. Abnormalities of the collecting system accounted for the most frequent cause of exclusion (n=41), with asymptomatic renal calculi being detected in 39 patients. Complex vascular anatomy and vascular abnormalities resulted in the exclusion of 29 patients. Supernumerary arteries and early arterial branching resulted in the exclusion of 20 patients, while renal vein anomalies leading to exclusion were uncommon (n=2). Abnormalities of renal parenchyma resulted in the exclusion of nine patients. Three patients were diagnosed with autosomal dominant polycystic kidney disease, two patients had renal cell carcinoma, and two patients had areas of cortical scarring. A complex cystic lesion requiring surveillance imaging was encountered in one patient and a large area of renal infarction related to prior adrenalectomy was demonstrated in one patient. Extra-renal abnormalities leading to exclusion were limited to two patients with pulmonary nodules. CONCLUSIONS: MDCT plays a critical role in the preoperative assessment of potential renal donors by identifying contraindications to donor nephrectomy and providing accurate vascular mapping. This study is anticipated to be informative for those involved in the workup of potential living renal donors by quantifying the incidence and reasons for donor exclusion identified on CT.

The role of thrombectomy and diffusion-weighted imaging with MRI in post-transplant renal vein thrombosis: a case report.

BACKGROUND: Surgical thrombectomy in the context of acute renal vein thrombosis (RVT) post-transplantation has had limited success, with considerable variation in the surgical techniques used. Unfortunately, it is usually followed by allograft nephrectomy within a few days if rapid allograft recovery does not ensue. We report a case of acute RVT in which nephrectomy was not performed despite a prolonged requirement for dialysis post-thrombectomy, but with recovery of renal function 2 weeks later. We also report the findings of serial MRI with diffusion-weighted imaging (DW-MRI) throughout the patient's recovery, which provided novel insights into allograft microvascular perfusion changes post-thrombectomy. CASE PRESENTATION: A 65-year old patient underwent living-unrelated kidney transplantation complicated by acute RVT. Surgical thrombectomy and irrigation led to a delayed, but significant, recovery of renal function. Serial non-contrast DW-MRI scanning was used to non-invasively assess microvascular renal blood flow post-operatively. Unlike standard Doppler ultrasonography, DW-MRI documented reduced microvascular perfusion initially, with gradual but incomplete recovery that mirrored the partial improvement in renal function. CONCLUSIONS: Our findings suggest that surgical thrombectomy may be more effective than previously described if followed by careful patient observation. Moreover, diffusion-weighted MRI appears to provide important insights into the pathophysiology of delayed graft function and deserves further investigation.

Effect of a Biopsy Center on Adequacy Rates of Thyroid Nodule Fine-Needle Aspiration.

OBJECTIVE: The purpose of this study was to investigate the effect of a biopsy center-a dedicated space with a dedicated ultrasound machine and technologist, staffed daily by a radiologist responsible for performing ultrasound-guided procedures only-on the rate of non-diagnostic or unsatisfactory thyroid fine-needle aspiration (FNA). MATERIALS AND METHODS: Three radiologists performed FNA on 1200 nodules in 998 patients between September 2010 and November 2015. We compared rates of nondiagnostic or unsatisfactory FNA before and after implementation of a biopsy center in September 2014 as part of a quality improvement initiative. Before the establishment of our biopsy center, ultrasound-guided procedures were scheduled between diagnostic studies in the main ultrasound department and were performed by a radiologist responsible for both. Multivariate logistic regression analysis was performed to assess the effect of the biopsy center on the odds of obtaining an adequate sample. RESULTS: Rates of nondiagnostic or unsatisfactory FNA decreased significantly from 15.1% to 8.5% (p < 0.001) after implementation of the biopsy center. The odds of obtaining an adequate sample were higher in the biopsy center (odds ratio, 2.07; 95% CI, 1.43-3.01), even after adjusting for patient age, nodule size, the radiologist performing the procedure, and time over the study period. CONCLUSION: The implementation of a biopsy center was associated with significantly lower rates of nondiagnostic or unsatisfactory thyroid FNA, suggesting target rates of 10% or lower are achievable with quality improvement measures.

A case of recurrent, multifocal anastomosing haemangiomas.

Anastomosing haemangiomas are relatively rare lesions, with a renal predilection, and which, given their imaging and pathologic appearance, mimic aggressive malignancies such as angiosarcoma. The imaging characteristics of this case are informative when evaluating a vascular lesion of the adrenal gland.

Non-Alcoholic Fatty Liver Disease in Early Pregnancy Predicts Dysglycemia in Mid-Pregnancy: Prospective Study.

OBJECTIVES: Non-alcoholic fatty liver disease (NAFLD) is mediated by insulin resistance, as is gestational diabetes mellitus (GDM). NAFLD has not been studied in relation to GDM. The objective of this study was to assess the association between first-trimester sonographic findings of NAFLD, and both dysglycemia and GDM in mid-pregnancy. METHODS: We followed a prospective cohort design at a large obstetrics clinic in Toronto, Ontario with 476 women enrolled in early pregnancy. NAFLD was assessed by ultrasound at 11-14 weeks gestation, and standardized images were independently scored by two ultrasonographers for the presence of hepatorenal contrast (one finding) and/or blurring of the intrahepatic vessels (one finding), relative to neither being present. Logistic regression analysis was used to generate odds ratios (ORs) and 95% confidence interval (CI) for the relation between 0, 1, or 2 sonographic findings of NAFLD and the composite outcome of impaired fasting glucose, impaired glucose tolerance, or GDM at 24-28 weeks gestation, determined by a fasting 75-g oral glucose tolerance test. ORs were adjusted (aOR) for maternal age, ethnicity, first-degree relative with type 2 DM, body mass index (BMI) at 11-14 weeks gestation, and change in BMI from 11-14 to 24-28 weeks gestation. RESULTS: Fifty out of 476 women (10.5%) developed the composite outcome. The presence of 1 (aOR 2.0, 95% CI: 1.0-4.1) or 2 (aOR 2.9, 95% CI: 1.0-18.4) sonographic features of NAFLD predicted the composite outcome. Limiting the analysis to ≥1 feature vs. none, the aOR was 2.2 (95% CI: 1.1-4.3). CONCLUSIONS: Sonographic assessment of NAFLD is a semiquantitative measure, with limited ability to detect small amounts of hepatic steatosis, or to distinguish various stages of NAFLD. First-trimester sonographic evidence of NAFLD predicts dysglycemia in mid-pregnancy.

Peer Review in Radiology: A Resident and Fellow Perspective.

PURPOSE: The purpose of this study was to explore Canadian radiology residents' and fellows' understanding, attitudes, opinions, and preferences toward peer review. METHODS: An Internet-based anonymous questionnaire designed to understand one's familiarity, attitudes, opinions, and preferences toward peer review was distributed to radiology residents and fellows across Canada. Data were analyzed using descriptive statistics, and answers were stratified by level of training. RESULTS: A total of 136 trainees responded to the survey with 92 completed survey responses available for descriptive statistics. Approximately half of respondents are familiar with peer review (49%), and 39% of trainees are involved in peer review. Most respondents (92%) expressed an interest in learning more about peer review; believe that it should be incorporated into the residency training curriculum (86%), be mandatory (72%), and that current participation will increase odds of future participation (91%). Most trainees (80%) are comfortable advising one another about errors, but less comfortable advising staff (21%). CONCLUSIONS: Residents and fellows welcome the opportunity to learn more about peer review and believe it should be incorporated into the residency training curriculum. Understanding the attitudes and perceptions held by trainees regarding peer review is important, as a means to optimize education and maximize current and future participation in peer review.

An unconventional therapeutic approach to a migratory IUD causing perforation of the rectum.

Intrauterine devices (IUDs) are a commonly used form of contraception. The risk of perforation and migration of these devices have been reported to be 1 in 1000. Migration into the rectum is even more uncommon. The following case illustrates a previously healthy 37-year-old woman who experienced a perforation and migration of an IUD into the rectum necessitating endoscopic removal. To our knowledge, this complication of IUD and subsequent endoscopic removal has not been previously described and presents a viable first-line therapeutic option in a stable patient.

Small bowel obstruction following computed tomography and magnetic resonance enterography using psyllium seed husk as an oral contrast agent.

The authors report a case series describing four patients who developed small bowel obstruction following the use of psyllium seed husk as an oral contrast agent for computed tomography or magnetic resonance enterography. Radiologists who oversee computed tomography and magnetic resonance enterography should be aware of this potential complication when using psyllium seed husk and other bulking agents, particularly when imaging patients with known or suspected small bowel strictures or active inflammation.

Comparison of 3% sorbitol vs psyllium fibre as oral contrast agents in MR enterography.

OBJECTIVE: To compare the degree of small bowel distension achieved by 3% sorbitol, a high osmolarity solution, and a psyllium-based bulk fibre as oral contrast agents (OCAs) in MR enterography (MRE). METHODS: This retrospective study was approved by our institutional review board. A total of 45 consecutive normal MRE examinations (sorbitol, n = 20; psyllium, n = 25) were reviewed. The patients received either 1.5 l of 3% sorbitol or 2 l of 1.6 g kg(-1) psyllium prior to imaging. Quantitative small bowel distension measurements were taken in five segments: proximal jejunum, distal jejunum, proximal ileum, distal ileum and terminal ileum by two independent radiologists. Distension in these five segments was also qualitatively graded from 0 (very poor) to 4 (excellent) by two additional independent radiologists. Statistical analysis comparing the groups and assessing agreement included intraclass coefficients, Student's t-test and Mann-Whitney U-test. RESULTS: Small bowel distension was not significantly different in any of the five small bowel segments between the use of sorbitol and psyllium as OCAs in both the qualitative (p = 0.338-0.908) and quantitative assessments (p = 0.083-0.856). The mean bowel distension achieved was 20.1 ± 2.2 mm for sorbitol and 19.8 ± 2.5 mm for psyllium (p = 0.722). Visualization of the ileum was good or excellent in 65% of the examinations in both groups. CONCLUSION: Sorbitol and psyllium are not significantly different at distending the small bowel and both may be used as OCAs for MRE studies. ADVANCES IN KNOWLEDGE: This is the first study to directly compare the degree of distension in MRE between these two common, readily available and inexpensive OCAs.