Canadian Association of Radiologists consensus guidelines for the prevention of contrast-induced nephropathy: update 2012.

PURPOSE: Contrast-induced acute kidney injury or contrast-induced nephropathy (CIN) is a significant complication of intravascular contrast medium (CM). These guidelines are intended as a practical approach to risk stratification and prevention. The major risk factor that predicts CIN is pre-existing chronic kidney disease. METHODS: Members of the committee represent radiologists and nephrologists across Canada. The previous guidelines were reviewed, and an in-depth up-to-date literature review was carried out. RESULTS: A serum creatinine level (SCr) should be obtained, and an estimated glomerular filtration rate (eGFR) should be calculated within 6 months in the outpatient who is stable and within 1 week for inpatients and patients who are not stable. Patients with an eGFR of ≥ 60 mL/min have an extremely low risk of CIN. The risk of CIN after intra-arterial CM administration appears be at least twice that after intravenous administration. Fluid volume loading remains the single most important measure, and hydration regimens that use sodium bicarbonate or normal saline solution should be considered for all patients with GFR < 60 mL/min who receive intra-arterial contrast and when GFR < 45 mL/min in patients who receive intravenous contrast. Patients are most at risk for CIN when eGFR < 30 mL/min. Additional preventative measures include the following: avoid dehydration, avoid CM when appropriate, minimize CM volume and frequency, avoid high osmolar CM, and discontinue nephrotoxic medications 48 hours before administration of CM.

Perception of radiation exposure and risk among patients, medical students, and referring physicians at a tertiary care community hospital.

BACKGROUND: It is important for physicians to be aware of the radiation doses as well as the risks associated with diagnostic imaging procedures that they are ordering. METHODS: A survey was administered to patients, medical students, and referring physicians from a number of specialties to determine background knowledge regarding radiation exposure and risk associated with commonly ordered medical imaging tests. RESULTS: A total of 127 patients, 32 referring physicians, and 30 medical students completed the survey. The majority of patients (92%) were not informed of the radiation risks associated with tests that they were scheduled to receive and had false perceptions about the use of radiation and its associated risks. Physicians and medical students had misconceptions about the use of ionizing radiation in a number of radiologic examinations; for example, 25% and 43% of physicians and medical students, respectively, were unaware that interventional procedures used ionizing radiation, and 28% of physicians were unaware that mammography used ionizing radiation. Computed tomographies and barium studies were thought to be associated with the least ionizing radiation among physicians. CONCLUSION: There is a need for educating the public, medical students, and referring physicians about radiation exposure and associated risk so that (1) patients receiving multiple medical imaging tests are aware of the radiation that they are receiving and (2) physicians and future physicians will make informed decisions when ordering such tests to limit the amount of radiation that patients receive and to promote informed consent among patients.

Behaviour and buoyancy regulation in the deepest-diving reptile: the leatherback turtle.

In the face of the physical and physiological challenges of performing breath-hold deep dives, marine vertebrates have evolved different strategies. Although behavioural strategies in marine mammals and seabirds have been investigated in detail, little is known about the deepest-diving reptile - the leatherback turtle (Dermochelys coriacea). Here, we deployed tri-axial accelerometers on female leatherbacks nesting on St Croix, US Virgin Islands, to explore their diving strategy. Our results show a consistent behavioural pattern within dives among individuals, with an initial period of active swimming at relatively steep descent angles (∼-40 deg), with a stroke frequency of 0.32 Hz, followed by a gliding phase. The depth at which the gliding phase began increased with the maximum depth of the dives. In addition, descent body angles and vertical velocities were higher during deeper dives. Leatherbacks might thus regulate their inspired air-volume according to the intended dive depth, similar to hard-shelled turtles and penguins. During the ascent, turtles actively swam with a stroke frequency of 0.30 Hz but with a low vertical velocity (∼0.40 ms(-1)) and a low pitch angle (∼+26 deg). Turtles might avoid succumbing to decompression sickness ('the bends') by ascending slowly to the surface. In addition, we suggest that the low body temperature of this marine ectotherm compared with that of endotherms might help reduce the risk of bubble formation by increasing the solubility of nitrogen in the blood. This physiological advantage, coupled with several behavioural and physical adaptations, might explain the particular ecological niche the leatherback turtle occupies among marine reptiles.

Role of radiology in geriatric care: a primer for family physicians.

OBJECTIVE: To present family physicians with the options available for diagnosing and treating a selection of common diseases in the elderly using diagnostic and interventional radiology. QUALITY OF EVIDENCE: Articles providing level I or II evidence were included in our review. Most articles presented results from randomized or other case-controlled studies. MAIN MESSAGE: Geriatric care has become a complicated, multidisciplinary effort, with the family physician often leading the team. The expanding cohort of patients is not only better informed than their predecessors, but also more demanding of better care through cutting-edge technology and treatment. Specifically, the role of radiology has expanded quickly in geriatric medicine. Because of complex clinical presentations and rising costs, it is essential for primary care physicians to understand the appropriate use of imaging and radiological intervention. CONCLUSION: There are a number of new and innovative radiological techniques and procedures available for elderly patients. This review aims to inform primary care physicians of a selected number of these techniques.

Imaging and transcatheter arterial embolization for traumatic splenic injuries: review of the literature.

The spleen is the most commonly injured visceral organ in blunt abdominal trauma in both adults and children. Nonoperative management is the current standard of practice for patients who are hemodynamically stable. However, simple observation alone has been reported to have a failure rate as high as 34%; the rate is even higher among patients with high-grade splenic injuries (American Association for the Surgery of Trauma [AAST] grade III-V). Over the past decade, angiography with transcatheter splenic artery embolization, an alternative nonoperative treatment for splenic injuries, has increased splenic salvage rates to as high as 97%. With the help of splenic artery embolization, success rates of more than 80% have also been described for high-grade splenic injuries. We discuss the role of computed tomography and transcatheter splenic artery embolization in the diagnosis and treatment of blunt splenic trauma. We review technical considerations, indications, efficacy and complication rates. We also propose an algorithm to guide the use of angiography and splenic embolization in patients with traumatic splenic injury.

Interdisciplinary Canadian guidelines on the use of metal stents in the gastrointestinal tract for oncological indications.

OBJECTIVE: To provide evidence-based guidelines regarding the appropriate use of gastrointestinal stents for oncologic indications. This document describes the use of gastrointestinal stents by appropriately trained physicians. METHODS: This document is based on a review of the published evidence and supplemented by consensus expert opinion. Gastrointestinal stenting has been evaluated in terms of technical success, complications, patient satisfaction, clinical outcome, and cost-benefit analysis. This document was approved by the Canadian Interventional Radiology Association; approval from the other relevant Canadian societies is pending. CONCLUSION: Gastrointestinal stenting has a valuable role in the management of gastrointestinal malignancy. The decision to use such devices should be taken after comprehensive multidisciplinary clinical, endoscopic, and radiologic evaluation.

Safety and efficacy of gastrointestinal stents in cancer patients at a community hospital.

OBJECTIVE: Increasing scientific evidence supports the use of self-expanding metallic gastrointestinal (GI) stents. The commonly accepted primary indications are their usefulness as a bridge to surgery and for palliation to avoid surgery. These stents have been shown to have high technical success and low complication rates, leading to improved quality of life for patients. They have also been shown to be cost-effective when compared with alternative therapies. The objective of this study is to present a retrospective review of our local experience. METHODS: Attempts were made to place 23 GI stents in 16 patients for palliative cancer indications. RESULTS: Follow-up was 5-352 days (mean 81.9 d). Presenting symptoms included abdominal distention or pain (81%), nausea or vomiting (69%), constipation (31%) and weight loss (19%). Stents were placed in the colon (11 patients), duodenum (4 patients) or esophagus (1 patient). The technical success rate was 91.3%, the clinical success rate (defined as any improvement in symptoms in patients successfully receiving a stent) was 85.7%, and the complication rate was 21.4% among patients successfully receiving a stent, or 18.8% overall. Of 14 patients successfully receiving at least 1 stent, 10 (71%) were discharged home after a mean of 11.5 days (range 1-26 d). Of patients successfully receiving at least 1 stent, 12 (86%) had passed away at the time of last follow-up. Patients who successfully received a stent but who have since passed away (either in hospital or out of hospital) had their stent(s) in situ for a mean of 57 days (range 5-180 d). CONCLUSION: On the basis of our data, we believe that GI stents may be safely and effectively used in a community hospital setting and that they provide benefit in the palliative care population.

Awareness of interventional radiology among patients referred to the interventional radiology department: a survey of patients in a large Canadian community hospital.

PURPOSE: To quantify the level of knowledge about interventional radiology (IR) among patients referred for an IR procedure and to develop recommendations on how to increase public awareness of IR. MATERIALS AND METHODS: Paper surveys were prospectively administered to consecutive patients scheduled to undergo an IR procedure at a community hospital. The study was terminated at the accrual of 100 completed surveys. RESULTS: Totals of 28% and 6% knew generally the job of a diagnostic radiologist and interventional radiologist, respectively, and 6% had heard of the field of IR before their referral (despite 21% having undergone a procedure previously). Before their arrival in the IR department, 87% had not received any information about IR. Three percent, 0%, 4%, 82%, and 82% had heard about uterine artery embolization, radiofrequency ablation, vertebroplasty, biopsy (any type), and angioplasty, respectively. After the procedures, 84% had a clearer view of what interventional radiologists do, but 98% believed that most others did not know what IR was. When asked how best to educate the public about IR, the responses were: unsure (39%), other (19%), pamphlets (12%), information from physicians (9%), television (8%), and Internet (7%). Overall, the mean satisfaction rate was 8.8 (with 0 representing the minimum and 10 representing the maximum), and 97% would choose IR over surgery for future treatments. CONCLUSIONS: These data quantify and strongly support the views that (1) even among patients specifically referred to IR for a procedure, the majority of people are unaware of what the field is or may offer; and (2) most patients were satisfied with their IR experience. Six results-based recommendations are made to increase public awareness about IR.

Successful recanalization of a longstanding complete left subclavian vein occlusion by radiofrequency perforation with use of a radiofrequency guide wire.

Treatment with radiofrequency (RF) energy can be used to ablate or perforate tissues. The latter involves lower power, higher voltage, and much shorter treatment time, and it is thought to induce much less collateral tissue damage. To date, RF perforation has been successfully used for various cardiac interventions; however, to our knowledge, there has not been a report of its use for peripheral vascular disease. This report describes the successful recanalization of a longstanding occlusion of a left subclavian vein in a 73-year-old woman with polycystic kidney disease and end-stage renal disease undergoing chronic hemodialysis treatment via an upper-extremity arteriovenous fistula. Multiple previous attempts at mechanical recanalization were unsuccessful. Recanalization was achieved by RF perforation with use of a PowerWire RF guide wire.