CT and MRI findings of acute calculous cholecystitis and its complications in Singapore: A pictorial review.

INTRODUCTION: Acute cholecystitis (AC) is a common problem encountered in surgical practice. This occurs due to obstruction of the cystic duct by calculi resulting in inflammation of the gallbladder. Increasingly, contrast enhanced computed tomography (CECT) and Magnetic Resonance Imaging (MRI) scans are being used for assessment. While the imaging features of AC are well recognized and extensively described in the literature, radiological features of the rarer complications related to AC such as pseudoaneurysm formation and gallbladder volvulus are less well known. We aim to describe these rarer findings in our pictorial review, to better educate the clinician and radiologist, such that timely diagnoses can be reached, and relevant management can be affected. METHODS: A collection of cases showing the common acute gallbladder pathologies and complications such as acute cholecystitis, gangrenous cholecystitis, emphysematous cholecystitis, haemorrhagic cholecystitis, Mirizzi's syndrome, gallbladder perforation and abscess formation, were collected between July 2016 and March 2018 at two different medical institutions in Singapore. In addition, rarer cases of gallbladder volvulus and vascular complications such as cystic artery pseudoaneurysms and vessel erosions, were also followed up. RESULTS: The CT and MRI imaging features of these conditions were discussed, with key diagnostic imaging features emphasized. CONCLUSION: Acute gallbladder pathologies are commonly encountered in day-to-day radiology practice. Knowledge of the rarer gallbladder pathologies and their key imaging features will help the radiologist, in particular, the on call radiologist in training, improve diagnostic accuracy and allow for timely management.

A case of xanthogranulomatous appendicitis in the female pelvis.

Xanthogranulomatous inflammation is an uncommon form of chronic inflammatory process. Only a few isolated case reports of xanthogranulomatous appendicitis (XA) have been published. XA has nonspecific imaging findings and cannot be reliably differentiated on imaging from locally advanced malignancy. XA however follows a benign course and can potentially be treated with surgical resection.

Predicting early recurrence of hepatocellular carcinoma with texture analysis of preoperative MRI: a radiomics study.

AIM: To investigate the feasibility of using texture analysis in preoperative magnetic resonance imaging (MRI) to predict early recurrence (ER) in hepatocellular carcinoma (HCC) post-curative surgery. MATERIAL AND METHODS: Institutional review board was obtained. A retrospective review of all patients who underwent hepatectomy between 1 January 2007 and 31 December 2015 was performed. Inclusion criteria included preoperative MRI, tumour size ≥1 cm, new cases of HCC. Exclusion criteria included loss to follow-up, ruptured HCCs, movement artefacts, and previous hepatectomy or interval adjuvant therapy. Patients were divided into ER and late or no recurrence (LNR) groups. ER was defined as new foci of HCC within 730 days of curative surgery. Radiomics feature extraction was performed on T2, diffusion-weighted imaging (DWI), T1 arterial, and T1 portovenous acquisitions on MATLAB (Mathworks, Matick, MA, USA). The MaZda software was used to analyse 290 texture parameters and PRTools was used for feature selection. RESULTS: Fifty patients (43 male, mean age 67 years) were divided into ER (n=20) and LNR (n=30) groups. Serum alpha-fetoprotein level (p=0.026), serum É£-glutamyltranspeptidase (p=0.014), Child-Pugh score (p=0.02) and the presence of vascular invasion (gross and/or microvascular, p=0.025) were found to be statistically significant different between the two groups. Parameters S(4,0)SumVarnc, S(0,3)SumOfSqs, and S(1,1)DifVarnc of the equilibrium phase were most accurate, achieving 84%, 82%, and 78% accuracy, respectively. CONCLUSION: Texture analysis of preoperative MRI has the potential to predict ER of HCC with up to 84% accuracy using an appropriate, single texture analysis parameter. Future studies are needed to validate these findings.

Scrotal emergencies: An imaging perspective.

Acute scrotal pain is a common complaint in emergency or primary care practice. A myriad of pathologies need to be considered, and while the clinical history often leads the clinician to the correct diagnosis, radiologists are often called upon to provide further diagnostic information through ultrasonography. Here, we present the sonographic features of various scrotal emergencies, as well as a few pitfalls. Through this, we explore the breadth of urgent pathologies that may be encountered, both traumatic and non-traumatic. For the clinician who performs point-of-care ultrasound, whether in clinic or in the emergency department, we hope that this pictorial article will lay a good foundation for confident and accurate image interpretation.

Thymic carcinoma presenting with an unusual and delayed metastasis to the neural foramen, mimicking thoracic spinal radiculopathy.

We report a case of metastatic thymic carcinoma which presented as an enhancing mass located in the neural foramen of the thoracic spine. More common tumours which arise in the neural foramen would include a neurogenic tumour or developmental anomalies such as a foregut duplication cyst. This case is singular firstly because the lesion present as radiculopathy which mimics a neurogenic tumour. Secondly, the presentation was unusually delayed as the patient presented to our centre more than a decade after the resection of the primary tumour in another institution.

SVM-based prediction of the calpain degradome using Bayes Feature Extraction.

Calpains belong to a family of calcium-dependent cysteine proteases which are implicated in a myriad of pathologies such as cancer and neurodegeneration. Despite extensive experimental studies on these proteases, our knowledge of the calpain degradome is still limited. Using a dataset of 341 unique, experimentally verified calpain cleavage sites, we conducted extensive sequence analyses and discovered novel residue propensities in the region flanking the cleavage site which could be modeled for prediction using machine learning algorithms. We have developed a series of computational models incorporating support vector machines and Bayes Feature Extraction for the prediction of calpain cleavage sites. The best models achieved AROC and accuracy scores ranging from 0.79 to 0.93 and 71% to 86% respectively when tested on independent test sets. We predicted calpain cleavage sites on proteins from the receptor tyrosine kinase family and discovered potential sites of cleavage at critical regulatory domains. The results suggest a novel role of calpains as a direct regulator of receptor tyrosine kinase activity in cell survival and cell death pathways.

Management of severe toxic epidermal necrolysis in children.

Toxic epidermal necrolysis (TEN) is a severe form of erythema multiforme that results in extensive epidermal sloughing; the condition is associated with a mortality of up to 70%. From 1991 to 1998, 10 children with severe toxic epidermal necrolysis were referred to a regional pediatric burn facility. Wounds were managed with strategy involving prevention of wound desiccation and superinfection, including the frequent use of biologic wound coverings. Children unable to guard their airway because of extensive oropharyngeal involvement were prophylactically intubated. Enteral nutrition was stressed. Steroids were not used and antibiotics were administered to managed specific foci of infection only. The 2 boys and 8 girls had an average age of 7.2+/-1.8 years (range 6 months to 15 years) and sloughed surface area of 76+/-6% of the body surface (range 50 to 95%). Antibiotics (3 children), anticonvulsants (3 children), nonsteroidals (2 children), and viral syndrome or unknown agents (2 children) were felt to have triggered the syndrome. Six children (60%) required intubation for an average of 9.7+/-1.8 days (range 2 to 14 days). Buccal mucosal involvement occurred in 9 (90%) and ocular involvement in 9 (90%). Although infectious complications were common (2 pneumonias, 2 urinary infections, 1 bacteremia, 2 central line infections, and 2 candidemias), all children survived after lengths of stay in the burn unit averaging 19+/-3 (range 6 to 40) days. The most common long-term morbidity was keratitis sicca (2 children, 20%), finger nail deformities (3 children, 30%), and variegated skin pigment changes (5 children, 50%). Although having both a cutaneous and visceral wound that predispose them to infectious complications, most children with TEN will survive if managed with a strategy emphasizing biologic wound closure, intensive nutritional support, and early detection and treatment of septic foci. Burn units have the resource set required to manage severe TEN and early referral of such children may have a favorable impact on survival.

Hyponatraemia and death after "ecstasy" ingestion.

A 15-year-old girl collapsed with respiratory arrest after taking "ecstasy" at a "dance party". She presented to hospital with hyponatraemia and cerebral oedema and later died. We postulate that ingestion of large amounts of water contributed to the hyponatraemia. Advice to those using ecstasy at dance parties should be modified to suggest moderate fluid intake only and to emphasise the need to seek prompt medical attention for non-resolving symptoms.

Prosthetic restoration of a nasal defect--a case report.

Restoration of facial defect makes very special demands on the maxillofacial prosthodontist. The key to successful rehabilitation includes good cosmetic result, proper selection of materials and excellent retention qualities. This case report presents a face disfigured by cancer which is restored with a silicone nasal prosthesis. Steps of the clinical and technical procedures of how a light-weight hollow prosthesis is fabricated are described. This special feature enhances retention and by incorporating a polyurethane lining, both aesthetics and retention are further improved, rehabilitating the patient and improving the quality of life. The basic requirements necessary for a successful facial prosthesis are also discussed.