Clinical outcomes and management of contrast hypersensitivity in patients requiring repeated computed tomography imaging.

Introduction: In collaboration with the Department of Rheumatology, Allergy and Immunology, our study aims to review the outcomes of and propose an improved workflow for the management of patients with prior hypersensitivity reactions to iodinated contrast media (ICM). Method: Outpatients coming for contrast-enhanced computed tomography (CECT) were stratified into 3 categories (definite, unconfirmed and inaccurate) based on likelihood of their contrast hypersensitivity label. Patients could be offered a different ICM, receive the same ICM, or be referred to an allergist for further evaluation. There were 4 outcomes: (1) alternative ICM tolerated; (2) same ICM tolerated again; (3) patient developed a hypersensitivity reaction to either alternative or original ICM; and (4) CECT was deferred until assessment by an allergist. Comparison was made pre- and post-intervention to see if patient outcomes were improved. Results: There were 132 patients who made a total of 154 visits (90.3% had documented contrast hypersensitivity). Post-intervention, the number of visits postponed for premedication decreased (81.0% to 34.7%). There was a reduction in hypersensitivity reactions (from 42.9% to 14.3%). Of the 12 patients assessed by the allergist, 6 could continue using the same or alternative ICM, 4 were advised to abstain from further contrast administration and 2 were pending testing with a third agent. Conclusion: Active intervention by the radiologist can decrease the number of postponed, converted or cancelled CECT studies as well as reduce the number of adverse allergic-like events. Direct collaboration between radiologist and allergist for specific cases may be helpful in patients who will likely need future/repeated CECTs.

Safety of a rapid outpatient hydration protocol for patients with renal impairment requiring intravenous iodinated contrast media for computed tomography.

INTRODUCTION: Patients receiving intravenous iodinated contrast media for computed tomography (CT) are predisposed to contrast-induced nephropathy. Chronic kidney disease is an important risk factor, and hydration is the mainstay of prevention. While inpatients can undergo intravenous hydration, limited knowledge exists regarding regimens for outpatients. We employed a rapid outpatient hydration protocol to reduce postponement of imaging appointments for patients with suboptimal estimated glomerular filtration rate (eGFR). METHODS: From June 2015, we amended our CT preparation protocol to mandate rapid hydration (oral, intravenous or both) for patients with an eGFR of 30-60 mL/min/1.73 m2. Patients receiving this hydration protocol from June to November 2015 were followed up for one month to monitor any admissions for fluid overload, and up to one year to determine the long-term effect on eGFR. RESULTS: 226 outpatients received the hydration protocol, which correlated with a 95% reduction in postponement of imaging appointments. No complications of fluid overload from hydration were encountered. A significant association was observed between age and decrease in eGFR, but this was not significant when stratified by drop in eGFR category. No statistical significance was found between decrease in eGFR and gender or race. Higher baseline eGFR was less likely to be associated with decrease in eGFR after imaging. Type of hydration was not related to a drop in eGFR category for patients with an eGFR of 45-59 mL/min/1.73 m2. CONCLUSION: We defined a shorter hydration regimen that is safe to use in the outpatient setting.

Isolated Systemic Arterial Supply to Normal Lung with Aneurysm Formation: A Rare Entity with An Even Rarer Complication.

BACKGROUND Isolated systemic arterial supply to normal (unsequestered) lung (ISSNL) without associated pulmonary malformation is rare, and lies towards the milder end of the spectrum of congenital lung abnormalities. Aneurysmal dilatation of the anomalous artery is an infrequent complication, with only 5 published cases thus far. CASE REPORT We present the case of a 61-year-old man whose screening chest radiograph showed a retrocardiac mass. Further evaluation with axial imaging demonstrated an ISSNL, complicated by aneurysmal dilatation. The genesis of this condition has been postulated to be due to persistence of primitive aortic branches to the developing lung bud. Initially reported in 1777, this entity is now more accurately classified within the spectrum of pulmonary and bronchovascular abnormalities, with refinement of the latter. The origin of an aberrant artery from the aorta implies that a higher-pressure systemic circulation is being shunted into a lower-pressure pulmonary circulation. While these supplying arteries are known to be large, aneurysmal dilation is exceptionally rare. Here, we review the cases published in the literature and present a case of our own. We aim to describe its pathogenesis, and touch on the classification systems and management. CONCLUSIONS ISSNL is usually first suspected on a screening chest radiograph, as many patients are asymptomatic. Based on contrast-enhanced axial imaging, the diagnosis can be established non-invasively. Definitive management includes surgical and endovascular techniques.

Clinics in diagnostic imaging (176). Acute embolic occlusion of the coeliac artery.

A 52-year-old man, who had a background of chronic heart disease and atrial fibrillation, as well as non-compliance with warfarin therapy, presented with a two-week history of worsening upper abdominal pain. Computed tomography mesenteric angiography showed complete embolic occlusion of the coeliac artery with resultant segmental splenic infarction, and thrombus within the left ventricle. A decision was made to proceed with catheter-directed thrombolysis. Subsequent follow-up angiogram at 12 hours showed successful treatment with complete dissolution of the coeliac embolus. The patient's symptoms resolved during his hospitalisation and he was subsequently discharged well on long-term oral anticoagulation therapy. Isolated acute embolic occlusion of the coeliac axis is a rare occurrence that may result in end-organ infarction. Treatment options include systemic anti-coagulation, mechanical thrombectomy, catheter thrombolysis or open surgery. Catheter-directed thrombolysis therapy is a feasible and effective option for treating acute thromboembolic occlusion of the coeliac artery.

Malignant Tumours Mimicking Complicated Appendicitis and Discovered upon Follow-Up after Percutaneous Drainage: A Case of Two Patients.

The conservative management of periappendiceal abscesses is gaining favour due to decreased morbidity and improved clinical outcomes for patients. Occasionally however an abscess can mask underlying sinister pathology. In this article, we highlight two cases of appendiceal adenocarcinoma that were initially diagnosed as periappendiceal abscesses and managed conservatively with percutaneous drainage. We also discuss clinical and imaging features that may assist with identifying a hidden malignancy when presented in these situations.

Congenital incomplete fusion of superior mesenteric artery mimicking dissection.

BACKGROUND: Both spontaneous SMA dissection and anatomical variants of GIT vasculature are well known entities. We present a case initially diagnosed as an SMA dissection on CT, but upon detailed review of the imaging findings was considered to be incompletely fused ventral segmental arteries--a rare anatomic variant not well described before. This finding is clinically significant, as it can mimic a vascular dissection and such a wrong diagnosis will lead to unnecessary investigation and intervention. CASE REPORT: A 62-year-old male patient presented with abdominal pain of uncertain etiology. The initial CT revealed an abnormal appearance of the superior mesenteric artery (SMA) which was diagnosed as SMA dissection. However, the appearance of this 'dissection' was unusual and there was a mismatch between the clinical presentation and radiological findings. The scan was reviewed and a 3D reconstruction of the abdominal aortal and visceral arteries was performed. The abnormal appearance of the SMA was deemed to be from a congenital anatomical variant. A review of the embryological origin of gut vasculature provides a likely explanation for this appearance. CONCLUSIONS: Ours is an unusual case of a developmental variant that has not been well described hitherto. Attention to the ancillary radiological signs and understanding the embryological origin of the abdominal vasculature is important to distinguish such variants from pathology.

Angioplasty of the anterior tibial artery through an incidentally discovered persistent sciatic artery.

The persistent sciatic artery (PSA) is a rare arterial variant. Patients may present with a spectrum of atherosclerotic disease, but aneurysm formation with thromboembolic complications is more common. Although no intervention is required for asymptomatic individuals, stenting for stenosis, thrombolysis for occlusion and even utilisation of the PSA for intrapelvic embolisation have been reported. Angioplasty via an incidentally discovered PSA has rarely been described.

An uncommon case of haemorrhagic enteric fever treated successfully with super-selective embolisation using polyvinyl alcohol particles and coils.

Lower gastrointestinal haemorrhage due to enteric fever is uncommon and potentially fatal. The majority of patients recover with conservative treatment, with surgery reserved for life-threatening bleeding. Given the advances in radiologically guided procedures, there have been numerous reports of successful embolisation for gastrointestinal haemorrhage, although few of these involved enteric fever as the causative agent. We report an uncommon case of haemorrhagic enteric fever treated successfully with embolisation using polyvinyl alcohol particles and coils.

Improved method of double-J ureteric stenting.

Double-J ureteral stents and antegrade stenting have been performed by radiologists for years. Various methods have been described, dependent on available equipment as well as technical expertise. As such, there is no definite consensus with regards to deployment of these stents. We describe an innovative technique, which would improve this procedure and highlight its advantages.

Effectiveness of an algorithm in reducing the number of unnecessary ultrasound scans for deep vein thrombosis: an evaluation report.

INTRODUCTION: Patients with suspected deep vein thrombosis (DVT) pose a diagnostic dilemma to the Emergency Department (ED) clinician. This study aimed to implement a known algorithm incorporating the modified Wells criteria and D-dimer testing to guide the ED clinician, thus reducing unnecessary ultrasound scans (USS). METHODS: Patients who presented to the ED between August 2008 and April 2009 with suspected DVT underwent Wells scoring. Those with scores < 2 were deemed unlikely to have DVT and underwent D-dimer testing first. Patients with scores ≥ 2 were regarded as likely to have DVT and underwent urgent USS. USS findings were tabulated as positive or negative/indeterminate for DVT. The latter group was followed up for one year to check whether DVT was missed during the initial USS. RESULTS: 75 patients presented with suspected DVT and underwent USS. Of these, 14 results were positive and 61 were negative. 37 patients had Wells scores < 2, with three (8.1%) having DVT. Another 38 patients had Wells scores ≥ 2, with 11 (28.9%) having DVT. D-dimer testing was performed on 27 of the 75 patients. Those with DVT had higher average values compared to those without DVT (1.305 vs. 0.595 µg/ml). The majority of patients with raised D-dimer values had cellulitis, although three also had DVT (with values ≥ 0.99 µg/ml). CONCLUSION: We managed to reduce the number of unnecessary USS and increase the pick-up rate of DVT. A cut-off score ≥ 2 in our algorithm is suitable for use in the ED setting.