Preparing IR for COVID-19: The Singapore Experience.

This paper describes country-wide special measures undertaken for interventional radiology staff during the current coronavirus disease 2019 (COVID-19) pandemic. Although each interventional radiology service around the world faces unique challenges, the principles outlined in this article will be useful when designing or strengthening individual practices and integrating them within wider hospital and national measures. Moving beyond the current outbreak, these measures will be useful for any future infectious diseases which are likely to arise.

Predicting late aortic complications after acute type A dissection surgery with volumetric measurements in a Singapore cohort.

Introduction: This study was conducted to evaluate the efficacy of postoperative computed tomography (CT) measurements of aortic lumen volumes in predicting aortic-related complications following acute type A aortic dissection (ATAAD) repair. Methods: We conducted a single-institution retrospective aortic volumetric analysis of patients after ascending aorta replacement performed during 2001-2015. The volumetric measurements of total lumen (total-L), true lumen (TL), false lumen (FL), as well as the TL:FL ratio from the first and second postoperative computer angiograms were obtained. A generalised structural equation model was created to analyse the predictive utility of TL:FL ratio. Results: One hundred and twenty-five patients underwent surgical intervention, of whom 97 patients were eventually discharged and analysed for postoperative complications. A total of 19 patients were included in the final analysis. Patients with late postoperative aortic complications had a significantly higher FL volume and total-L volume on the first (FL volume P = 0.041, total-L volume P = 0.05) and second (FL volume P = 0.01, total-L volume P = 0.007) postoperative scans. The odds of having aortic complications were raised by 1% with a 1 cm3 increase in total-L volume and by 2% with a 1 cm3 increase in FL volume. The TL:FL ratio was significantly lower in patients who developed complications. Conclusion: Postoperative CT volumetric measurements in patients who developed complications are characterised by a significant increase in the FL volume and total-L volume from the first postoperative scans. Patients with disproportionately expanded FL presenting with TL:FL ratios less than 1 were associated with aortic complications. Hence, the TL:FL ratio may be a reliable and useful parameter to monitor postoperative disease progression and to evaluate the risk of late complications in ATAAD patients.

Enzymatic reaction in droplets manipulated with liquid dielectrophoresis.

Droplet generation and transportation for biological reactions are conducted with liquid dielectrophoresis (LDEP), forming two hundred picoliter droplets and aligning them in an open environment above the micro-machined electrodes. The generation of the dielectrophoresis signals was critically examined to actuate droplets in biological solutions without excessive Joule heating. Enzymatic reactions between ß-galactosidase and fluorescein di-ß-D-galactopyranoside were succeeded in manipulated droplets, which was confirmed by fluorescence imaging. These results allow us to propose the integration of LDEP actuation in high throughput biomolecular assays.

Primary Hyperparathyroidism Causing Psychosis: A Case Report.

New-onset psychotic symptoms presenting late in life can be caused by various medical and psychiatric conditions. The index of suspicion for an organic cause for psychotic symptoms in an elderly person should be high, and every presenting patient should undergo a detailed history-taking and evaluation before attributing these symptoms to a primary psychiatric condition. Hyperparathyroidism is one condition that can present with psychiatric symptoms such as low mood and anxiety. While psychiatric symptoms are not uncommon in hyperparathyroidism, acute psychosis is rare. This case report highlights the importance of a thorough evaluation of an elderly person presenting with a new onset of psychosis.

The Role of Interventional Radiology in the Diagnosis and Treatment of Pulmonary Arteriovenous Malformations.

Pulmonary arteriovenous malformations (PAVMs) are uncommon, predominantly congenital direct fistulous connections between the pulmonary arteries and pulmonary veins, resulting in a right to left shunt. Patients with PAVMs are usually asymptomatic with lesions detected incidentally when radiological imaging is performed for other indications. In this review, we discuss the classification and radiological features of PAVMs as well as their treatment and follow-up options, with a particular focus on percutaneous endovascular techniques and the evolution of the available equipment for treatment.

How to do it: value-driven sharp recanalization of central vein occlusion.

Patients on haemodialysis are susceptible for central vein occlusions, which can result in debilitating clinical consequences. These may be resistant to conventional revascularization with guidewire and catheter technique. Value-driven sharp recanalization of central vein occlusion is depicted as a safe and affordable option.

Non-randomized safety and performance evaluation of the av-Guardian vascular access system.

INTRODUCTION: The ability to successfully cannulate the arteriovenous fistula reliably is a critical step in the delivery of hemodialysis therapy. The av-Guardian vascular access system (Advent Access, Singapore) is designed to overcome the technical barrier to establishing reliable blunt needle access in patients with mature arteriovenous fistula. METHODS: This was a first-in-man, prospective, non-randomized trial (registered on the Australian New Zealand Clinical Trial Registry (ACTRN12617000501347)) performed to assess the safety and feasibility of achieving repeatable successful cannulation via av-Guardian vascular access system to facilitate blunt needling in patients with mature arteriovenous fistula. The primary endpoints of the study included rate of successful hemodialysis sessions via av-Guardian vascular access system cannulation over 3 months and safety of the implants. RESULTS: A total of six patients (four patients with brachiocephalic and two with radiocephalic arteriovenous fistula) were enrolled in the study. A pair of av-Guardian vascular access system were implanted, one each at the arterial and venous cannulation sites, under local anesthesia. Overall, the rate of successful cannulation through the av-Guardian vascular access system over 3 months in 216 hemodialysis sessions was 98.1% (212/216) at the arterial site and 94.4% (204/216) at the venous site. Significantly, 90% and 85.5% of the cannulations at the arterial and venous site, respectively, were successful at first attempt. Blood flow rates within the arteriovenous fistula were unaffected by the devices. CONCLUSION: The results demonstrated the safety and feasibility of a subcutaneously implanted, extravascular device in achieving repeatable successful cannulation via a constant site, to facilitate blunt needling in matured arteriovenous fistula in limited number of patients.

Whole Exome Sequencing of Multi-Regional Biopsies from Metastatic Lesions to Evaluate Actionable Truncal Mutations Using a Single-Pass Percutaneous Technique.

We investigate the feasibility of obtaining multiple spatially-separated biopsies from a single lesion to explore intratumor heterogeneity and identify actionable truncal mutations using whole exome sequencing (WES). A single-pass radiologically-guided percutaneous technique was used to obtain four spatially-separated biopsies from a single metastatic lesion. WES was performed to identify putative truncal variants (PTVs), defined as a non-synonymous somatic (NSS) variant present in all four spatially separated biopsies. Actionable truncal mutations-filtered using the FoundationOne panel-were defined as clinically relevant PTVs. Mutational landscapes of each biopsy and their association with patient outcomes were assessed. WES on 50 biopsied samples from 13 patients across six cancer types were analyzed. Actionable truncal mutations were identified in 9/13 patients; 31.1 ± 5.12 more unique NSS variants were detected with every additional multi- region tumor biopsy (MRTB) analyzed. The number of PTVs dropped by 16.1 ± 17.9 with every additional MRTB, with the decrease most pronounced (36.8 ± 19.7) when two MRTB were analyzed compared to one. MRTB most reliably predicted PTV compared to in silico analysis of allele frequencies and cancer cell fraction based on one biopsy sample. Three patients treated with actionable truncal mutation-directed therapy derived clinical benefit. Multi-regional sampling for genomics analysis is feasible and informative to help prioritize precision-therapy strategies.

Lumbar Artery Bleed as a Complication of Percutaneous Renal Biopsy and a Proposed Workflow for Massive Bleeding.

Injuries to extrarenal arteries caused by percutaneous biopsy needles are very rare but highly lethal due to delay in recognition. Here we report the case of an inadvertent lumbar artery puncture after native renal biopsy and provide a literature review and a proposed workflow for management of massive bleed after renal biopsy. This case highlights evidence-based management considerations regarding massive bleed after renal biopsy, including the first-line imaging modality and the need to consider extrarenal site bleed. While angiographic embolization is an effective method of control of haemorrhage, surgical exploration is required in a proportion of cases for control of bleeding. Centre-specific workflows should be adopted to minimize the mortality and morbidity associated with massive bleed after renal biopsy.

Coronary and arch hybrid surgery in a patient with infrarenal aortic occlusion.

A 65-year-old gentleman with claudication underwent contrast-enhanced computed tomography. The scan showed occlusion of the infrarenal abdominal aorta and a 6.0 × 3.7 cm saccular zone-3 arch aneurysm. The left ventricular ejection fraction was 35% and a coronary angiogram revealed triple-vessel disease. In view of the patient's high risk with EuroSCORE II 20.34%, coronary artery surgery was combined with hybrid type I arch aneurysm repair. An endovascular stent was delivered in an antegrade manner. Open heart surgery and a hybrid type I arch intervention can be performed simultaneously through a midline sternotomy approach.

Metastatic breast cancer to the rectum: A case report with emphasis on MRI features.

RATIONALE: Less than 1% of breast carcinomas metastasize to the gastrointestinal tract. The diagnosis is frequently not recognized especially when the history of breast carcinoma is remote. PATIENT CONCERNS: A 61-year-old female with a remote history of breast carcinoma presented with a 3-month history of change in bowel habits. Colonoscopy showed a circumferential rectal mass with initial impression of primary rectal cancer. MRI of the rectum showed findings that are atypical for primary rectal cancer. DIAGNOSES: Deep biopsy of the rectal mass confirmed lobular breast carcinoma metastasis to the rectum. INTERVENTION AND OUTCOMES: The patient was treated with radiotherapy and hormonal therapy. She is symptomatically well 2 years after presentation and remains on hormonal therapy. LESSONS: Lobular breast cancer which metastasizes to the rectum can mimic primary rectal cancer clinically. The unique MRI features described in our case when present with a concordant history of lobular breast carcinoma should alert the radiologist to the possibility of this diagnosis which has important treatment implications.

CT features in surgically proven cases of ovarian torsion-a pictorial review.

Ovarian torsion is a surgical emergency characterized by a partial or complete rotation of the ovarian vascular pedicle, causing obstruction to venous outflow followed by arterial inflow. Clinically, ovarian torsion frequently mimics other causes of acute pelvic pain such as appendicitis, diverticulitis, renal colic etc. Ultrasonography is the first-line imaging modality of choice for evaluation of ovarian torsion. MRI is useful as a problem-solving tool in patients with equivocal or non-diagnostic ultrasonography studies. CT is ordinarily not utilized in a young female with suspected ovarian torsion due to the radiation dose. However, the significant expansion in use of CT imaging in emergency departments for female patients presenting with acute abdominal pain has increased the likelihood that ovarian torsion may be first seen on CT. In addition, a non-specific clinical presentation may lead to an initial imaging with CT rather than ultrasonography. Ultrasound features of the ovarian torsion are well known and sufficiently described across literature as compared with the CT scan findings. In view of the increasing usage of CT as the modality of choice in emergency settings, it is imperative for the radiologist to familiarize with the CT features of ovarian torsion. An early correct diagnosis by the radiologist in clinically unsuspected cases, facilitating a prompt surgery to restore the ovarian blood flow can prevent permanent irreversible damage. There is limited published data available on the CT features of ovarian torsion. This pictorial essay illustrates CT findings with histological correlation of surgically proven ovarian torsion in our institution. These patients were primarily investigated with CT scan for acute pelvic pain ascribed to non-gynaecological causes such as bowel or urinary tract lesions.

The role of cranial CT in the investigation of meningitis.

OBJECTIVE: To assess the usage of cranial computed tomography (CT) in patients admitted with meningitis. DESIGN: Retrospective study. SETTING: Heart of England NHS foundation trust, a teaching hospital in the West Midlands. PARTICIPANTS: Two groups of adult patients admitted with meningitis between April 2001 and September 2004 and from September 2006 until September 2009. MAIN OUTCOME MEASURES: The numbers of patients having cranial CT and lumbar puncture and whether any complications had arisen following lumbar puncture. The appropriateness of the CT request according to local criteria. RESULTS: A total of 111 patients were admitted in the initial time period and 47 patients in the second time period. In the first group, 67 patients underwent CT (61%), compared with 36 patients (80%) in the second group. There were eight abnormal scans (12%) in the initial group including three patients with radiological features of cerebral oedema. Of these patients, one underwent lumbar puncture and had no neurological sequelae. In the second group, there were five abnormal scans (14%) with one presenting a contraindication for lumbar puncture due to mild ventricular dilatation. A lumbar puncture was performed in this patient without complication. All patients with abnormal scans had clinical features to suggest raised intracranial pressure. CT scan requests were considered inappropriate in 26% of patients in the initial study period and 56% of patients in the second study period. CONCLUSION: More patients with meningitis are undergoing CT and the number of inappropriate requests are increasing. There are few abnormal CT scans presenting a contraindication for lumbar puncture and the majority of these patients usually have clinical signs to suggest raised intracranial pressure.