Image quality and radiologists’ subjective acceptance using model-based iterative and deep learning reconstructions as adjuncts to ultrahigh-resolution CT in low-dose contrast-enhanced abdominopelvic CT: phantom and clinical pilot studies

Purpose In contrast-enhanced abdominopelvic CT (CE-APCT) for oncologic follow-up, ultrahigh-resolution CT (UHRCT) may improve depiction of fine lesions and low-dose scans are desirable for minimizing the potential adverse effects by ionizing radiation. We compared image quality and radiologists’ acceptance of model-based iterative (MBIR) and deep learning (DLR) reconstructions of low-dose CE-APCT by UHRCT. Methods Using our high-resolution (matrix size: 1024) and low-dose (tube voltage 100 kV; noise index: 20–40 HU) protocol, we scanned phantoms to compare the modulation transfer function and noise power spectrum between MBIR and DLR and assessed findings in 36 consecutive patients who underwent CE-APCT (noise index: 35 HU; mean CTDIvol: 4.2 ± 1.6 mGy) by UHRCT. We used paired t-test to compare objective noise and contrast-to-noise ratio (CNR) and Wilcoxon signed-rank test to compare radiologists’ subjective acceptance regarding noise, image texture and appearance, and diagnostic confidence between MBIR and DLR using our routine protocol (matrix size: 512; tube voltage: 120 kV; noise index: 15 HU) for reference. Results Phantom studies demonstrated higher spatial resolution and lower low-frequency noise by DLR than MBIR at equal doses. Clinical studies indicated significantly worse objective noise, CNR, and subjective noise by DLR than MBIR, but other subjective characteristics were better (P < 0.001 for all). Compared with the routine protocol, subjective noise was similar or better by DLR, and other subjective characteristics were similar or worse by MBIR. Conclusion Image quality, except regarding noise characteristics, and acceptance by radiologists were better by DLR than MBIR in low-dose CE-APCT by UHRCT. Graphical abstract

Relevance of Routine Abdominopelvic Ultrasound in Suspected Child Abuse in Children Under 2 years of Age: Review of 15 years of Experience

In France, the current recommendation is to perform a routine abdominopelvic ultrasound in any child under 2 years of age who is suspected to have been abused. We retrospectively studied the relevance of this practice in our center over the past fifteen years. This was a descriptive, retrospective study of all children under 2 years of age who had been subject to suspected abuse. Abdominal images and reports were reviewed and cross-referenced with possible clinical and biological signs. Four hundred and five children were included between 2006 and 2020, of whom 296 underwent abdominal imaging (2 initial abdominopelvic CT scans, 4 ultrasounds followed by CT scans, and 290 ultrasounds alone). Four examinations revealed traumatic abnormalities related to abuse. These four children all had clinical or biological anomalies. In the absence of clinical or biological signs, no imagery showed any abnormality related to abuse.

A deep Residual U-Net algorithm for automatic detection and quantification of ascites on the abdominopelvic computed tomography acquired in the emergency department (Preprint)

BACKGROUND Detection and quantification of intraabdominal free fluid (i.e., ascites) on computed tomography (CT) are essential processes to find emergent or urgent conditions in patients. In an emergent department, automatic detection and quantification of ascites will be beneficial. OBJECTIVE We aimed to develop an artificial intelligence (AI) algorithm for the automatic detection and quantification of ascites simultaneously using a single deep learning model (DLM). METHODS 2D deep learning models (DLMs) based on a deep residual U-Net, U-Net, bi-directional U-Net, and recurrent residual U-net were developed to segment areas of ascites on an abdominopelvic CT. Based on segmentation results, the DLMs detected ascites by classifying CT images into ascites images and non-ascites images. The AI algorithms were trained using 6,337 CT images from 160 subjects (80 with ascites and 80 without ascites) and tested using 1,635 CT images from 40 subjects (20 with ascites and 20 without ascites). The performance of AI algorithms was evaluated for diagnostic accuracy of ascites detection and for segmentation accuracy of ascites areas. Of these DLMs, we proposed an AI algorithm with the best performance. RESULTS The segmentation accuracy was the highest in the deep residual U-Net with a mean intersection over union (mIoU) value of 0.87, followed by U-Net, bi-directional U-Net, and recurrent residual U-net (mIoU values 0.80, 0.77, and 0.67, respectively). The detection accuracy was the highest in the deep residual U-net (0.96), followed by U-Net, bi-directional U-net, and recurrent residual U-net (0.90, 0.88, and 0.82, respectively). The deep residual U-net also achieved high sensitivity (0.96) and high specificity (0.96). CONCLUSIONS We propose the deep residual U-net-based AI algorithm for automatic detection and quantification of ascites on abdominopelvic CT scans, which provides excellent performance.

Abdominopelvic CT-scan in emergency departments for patients with suspected complications of Crohn’s disease: a single tertiary center experience

Background Crohn’s disease (CD) is a chronic disorder with frequent complications. The objective of this study was to assess the predictive factors of finding a complication of CD using abdominopelvic CT-scan in patients with a visit to the emergency department. Methods Patients with at least one visit to the gastroenterology department of our University hospital during the year with a CD were retrospectively included. All visits to the emergency department of the hospital during the follow-up of these patients were identified. Results A total of 638 patients were included and 318 (49.8%) had at least one visit to the emergency department since the beginning of their follow-up. Abdominopelvic CT-scan was performed in 141 (23.7%) of the 595 visits for digestive symptoms. Only 4.3% of these CT-scans were considered as normal; there was luminal inflammation without complication in 24.8%, abscess, fistula or perforation in 22.7%, mechanical bowel obstruction in 36.9% and diagnosis unrelated to CD in 11.3%. In univariate analysis, stricturing phenotype (OR, 2.48; 95% CI, 1.16–5.29; p = 0.02) and previous surgery (OR, 2.90; 95% CI, 1.37–6.14; p = 0.005) were predictive factors of finding a complication of CD using abdominopelvic CT-scan, whereas no independent predictive factor was statistically significant in multivariate analysis. Conclusion In CD patients consulting in emergency department, CT-scan examination was performed in 24% of visits for digestive symptoms and complications of CD were found in 60%. Complications were more frequent in patients with stricturing phenotype and previous surgery.

Diagnostic performance and image quality of deep learning image reconstruction (DLIR) on unenhanced low-dose abdominal CT for urolithiasis

Background Patients with urolithiasis undergo radiation overexposure from computed tomography (CT) scans. Improvement of image reconstruction is necessary for radiation dose reduction. Purpose To evaluate a deep learning-based reconstruction algorithm for CT (DLIR) in the detection of urolithiasis at low-dose non-enhanced abdominopelvic CT. Material and Methods A total of 75 patients who underwent low-dose abdominopelvic CT for urolithiasis were retrospectively included. Each examination included three reconstructions: DLIR; filtered back projection (FBP); and hybrid iterative reconstruction (IR; ASiR-V 70%). Image quality was subjectively and objectively assessed using attenuation and noise measurements in order to calculate the signal-to-noise ratio (SNR), absolute contrast, and contrast-to-noise ratio (CNR). Attenuation of the largest stones were also compared. Detectability of urinary stones was assessed by two observers. Results Image noise was significantly reduced with DLIR: 7.2 versus 17 and 22 for ASiR-V 70% and FBP, respectively. Similarly, SNR and CNR were also higher compared to the standard reconstructions. When the structures had close attenuation values, contrast was lower with DLIR compared to ASiR-V. Attenuation of stones was also lowered in the DLIR series. Subjective image quality was significantly higher with DLIR. The detectability of all stones and stones >3 mm was excellent with DLIR for the two observers (intraclass correlation [ICC] = 0.93 vs. 0.96 and 0.95 vs. 0.99). For smaller stones (<3 mm), results were different (ICC = 0.77 vs. 0.86). Conclusion For low-dose abdominopelvic CT, DLIR reconstruction exhibited image quality superior to ASiR-V and FBP as well as an excellent detection of urinary stones.

POS0035 ONE IN TWENTY INFLAMMATORY BOWEL DISEASE PATIENTS WHO UNDERWENT ABDOMINOPELVIC COMPUTED TOMOGRAPHY HAVE UNDIAGNOSED AXIAL SPONDYLOARTHRITIS

Background:The diagnosis of axial spondyloarthritis (axSpA) is challenging and hindered by delay. There may be an opportunity to identify sacroiliitis for further rheumatology review in inflammatory bowel disease (IBD) patients who undergo Computed Tomography (CT) for non-musculoskeletal (MSK) indications.Objectives:To identify what proportion of IBD patients who underwent abdominopelvic CT for non-MSK indications have axSpA and to explore the role of an imaging strategy for identifying axSpA.Methods:Abdominopelvic CT scans of verified IBD patients were identified retrospectively from eight years of imaging archive. Patients between 18-55 yrs. were selected as having the highest diagnostic yield for axSpA. CT review (using criteria from a validated CT screening tool developed by Chan1) was undertaken by a trained radiology team for presence of CT-defined sacroiliitis (CTSI). All CTSI patients were sent a screening questionnaire. Those with self-reported chronic back pain (CBP), duration > 3 months, onset < 45 years were invited for rheumatology review. This included a medical interview, physical examination (joint count, MASES, dactylitis count, BASMI), patient reported outcomes (BASDAI, BASFI, BASGI, Harvey-Bradshaw-Index, Partial-Mayo-Index), relevant laboratory tests (CRP, ESR, HLA-B27), axSpA protocol MRI, and remote review by a panel of experienced rheumatologists with a special interest in axSpA.Results:CTSI was identified in 60 of 301 patients. Thirty-two (53%) responded to the invitation to participate and 27 (84%) were enrolled. Of these, eight had a pre-existing axSpA diagnosis and five did not report chronic back pain. Fourteen patients underwent rheumatological assessment; three of 14 (21.4% [95% CI: 4.7%, 50.8%]) had undiagnosed axSpA. In total, 11 of 27 (40.7% [95% CI: 22.4%, 61.2%]) patients had a rheumatologist verified diagnosis of axSpA.Conclusion:One in five patients (60/301) with IBD who underwent abdominopelvic CT for non-MSK indications have CTSI and at least one in five (11/60) have axSpA. Five percent (3/60) were previously undiagnosed. This highlights a hidden disease burden and a potential strategy for identifying new cases.References:[1]Chan J, Sari I, Salonen D, Inman RD, Haroon N. Development of a Screening Tool for the Identification of Sacroiliitis in Computed Tomography Scans of the Abdomen. J Rheumatol 2016; 43(9); 1687-94.Acknowledgements:We are indebted to Baljeet Dhillon and Shin Azegami for their assistance in the scoring of the CTSI.Disclosure of Interests:Chong Seng Edwin Lim Grant/research support from: AbbVie, Louise Hamilton: None declared, Samantha Low: None declared, Andoni Toms: None declared, Alex MacGregor: None declared, Karl Gaffney Speakers bureau: AbbVie, Eli Lilly, Novartis, UCB Pharma, Consultant of: AbbVie, Eli Lilly, Novartis, UCB Pharma, Grant/research support from: AbbVie, Gilead, Eli Lilly, Novartis, UCB Pharma.

Graves’ Disease Induced Severe Hypercalcemia

Introduction: Hyperthyroidism is a well-known non-parathyroid hormone-mediated cause of hypercalcemia. Hypercalcemia associated with thyrotoxicosis is usually asymptomatic. Increased osteoclastogenesis is one of the mechanisms underlying this etiology. Hyperthyroidism is associated with mild to moderate levels of hypercalcemia in approximately 20% of patients, but severe hypercalcemia is rare. We report a case of a male with Grave’s disease-induced symptomatic severe hypercalcemia. Clinical Case: A 36-year-old male with type 2 diabetes mellitus and arterial hypertension who was transferred from another institution to our Emergency Department due to suspected primary hyperparathyroidism for Endocrinology Services evaluation. Family history is non-contributory. Patient reports palpitations, irritability, and unintentional weight loss of approximately fifty pounds in nine months. One month ago, he started with constipation, anxiety, depression, abdominal discomfort, nausea, and vomiting for which decided to seek medical attention. Physical examination was remarkable for tachycardia, dry mucous membranes, and goiter. Laboratory tests showed lipase 69 U/L (13-60U/L), albumin-corrected calcium 14.3 mg/dL (8.8-10.3mg/dL), phosphorus 3.30 mg/dL (2.4-4.2mg/dL), magnesium 1.58 mg/dL (1.8-2.2mg/dL), creatinine 1.38 mg/dL (0.90-1.30 mg/dL), alkaline phosphatase 77 IU/L (43-115IU/L), iPTH 4 pg/mL (11-67pg/mL), PTHrp &lt;0.4 pmol/L (≤4.2pmol/L), 25-OH vitamin D 32.1 ng/mL (30-100ng/mL), 1,25-dihydroxyvitamin D &lt;5.0 pg/mL(19.9-79.3pg/mL), hemoglobin 11.6 g/dL (14-18g/dL), negative serum and urine protein electrophoresis, TSH 0.003 uIU/mL (0.45-5.33 uIU/mL), free T4 2.80 ng/dL (0.71-1.85ng/dL), total T3 2.57 ng/mL (0.80-2.00ng/mL), TSI: 486% (&lt;140%), urine calcium 24hr 525mg/day (100-300mg/day). Thoracic and abdominopelvic CT scan without contrast was unremarkable for masses, adenopathies, osseous lesions, or acute abdominal processes. Patient was treated with IV isotonic saline and methimazole 10mg oral daily with resolution of symptoms. Finally, diagnosed with Graves’ disease as the cause of hypercalcemia after ruling out other etiologies. He was discharged home with calcium levels 10.8 mg/dL, normal renal function, methimazole, and follow up with Endocrinology Services. Conclusion: This is a case of an atypical presentation of hyperthyroidism-induced symptomatic hypercalcemia. It is important to consider hyperthyroidism in the differential diagnoses of severe hypercalcemia. Prompt suspicion is essential due to the effective treatments available for Graves’ disease. Early treatment of hypercalcemia is important for quick resolution of symptoms and decreased associated mortality.