Adding non-contrast and delayed phases increases the diagnostic performance of arterial CTA for suspected active lower gastrointestinal bleeding.

OBJECTIVES: When assessing for lower gastrointestinal bleed (LGIB) using CTA, many advocate for acquiring non-contrast and delayed phases in addition to an arterial phase to improve diagnostic performance though the potential benefit of this approach has not been fully characterized. We evaluate diagnostic accuracy among radiologists when using single-phase, biphasic, and triphasic CTA in active LGIB detection. METHOD AND MATERIALS: A random experimental block design was used where 3 blinded radiologists specialty trained in interventional radiology retrospectively interpreted 96 CTA examinations completed between Oct 2012 and Oct 2017 using (1) arterial only, (2) arterial/non-contrast, and (3) arterial/non-contrast/delayed phase configurations. Confirmed positive and negative LGIB studies were matched, balanced, and randomly ordered. Sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, positive and negative predictive values, and time to identify the presence/absence of active bleeding were examined using generalized estimating equations (GEE) with sandwich estimation assuming a binary distribution to estimate relative benefit of diagnostic performance between phase configurations. RESULTS: Specificity increased with additional contrast phases (arterial 72.2; arterial/non-contrast 86.1; arterial/non-contrast/delayed 95.1; p < 0.001) without changes in sensitivity (arterial 77.1; arterial/non-contrast 70.2; arterial/non-contrast/delayed 73.1; p = 0.11) or mean time required to identify bleeding per study (s, arterial 34.8; arterial/non-contrast 33.1; arterial/non-contrast/delayed 36.0; p = 0.99). Overall agreement among readers (Kappa) similarly increased (arterial 0.47; arterial/non-contrast 0.65; arterial/non-contrast/delayed 0.79). CONCLUSION: The addition of non-contrast and delayed phases to arterial phase CTA increased specificity and inter-reader agreement for the detection of lower gastrointestinal bleeding without increasing reading times. KEY POINTS: • A triphasic CTA including non-contrast, arterial, and delayed phase has higher specificity for the detection of lower gastrointestinal bleeding than arterial-phase-only protocols. • Inter-reader agreement increases with additional contrast phases relative to single-phase CTA. • Increasing the number of contrast phases did not increase reading times.

Acute Lower Gastrointestinal Bleeding: Temporal Factors Associated With Positive Findings on Catheter Angiography After (99m)Tc-Labeled RBC Scanning.

OBJECTIVE: The objective of the study was to determine if time to positive (TTP), defined as the time from the start of (99m)Tc-labeled RBC scanning to the appearance of a radionuclide blush (considered to be a positive finding for acute lower gastrointestinal bleeding [LGIB]), and lag time (LT), defined as the time from the appearance of a radionuclide blush to the start of catheter angiography (CA), affected the yield of CA for the detection of acute LGIB. MATERIALS AND METHODS: TTP and LT were retrospectively evaluated in 120 patients who had positive findings for acute LGIB on (99m)Tc-labeled RBC scanning and subsequently underwent CA for the diagnosis and localization of gastrointestinal bleeding. Two nuclear medicine fellowship-trained radiologists independently reviewed the (99m)Tc-labeled RBC scans. Two fellowship-trained interventional radiologists independently reviewed the angiograms. All data were analyzed using SAS software. RESULTS: When a TTP threshold of ≤ 9 minutes was used, the sensitivity, specificity, positive predictive value, and negative predictive value for a positive CA study were 92%, 35%, 27%, and 94%, respectively. In addition, the odds of detecting bleeding on CA increased 6.1-fold with a TTP of ≤ 9 minutes relative to a TTP of > 9 minutes (p = 0.020). A significant inverse relationship was found between LT and a positive CA study (p = 0.041). CONCLUSION: TTP and LT impact the rate of positive CA studies. A TTP threshold of ≤ 9 minutes allows the detection of almost all patients who would benefit from CA for treatment and allows a reduction in unnecessary negative CA studies. The likelihood of positive findings on CA decreases with a delay in the performance of CA.

The preclose technique in percutaneous endovascular aortic repair: a systematic literature review and meta-analysis.

PURPOSE: To establish the efficacy and safety of the preclose technique in total percutaneous endovascular aortic repair (PEVAR). METHODS: A systematic literature search of Medline database was conducted for series on PEVAR published between January 1999 and January 2012. RESULTS: Thirty-six articles comprising 2,257 patients and 3,606 arterial accesses were included. Anatomical criteria used to exclude patients from undergoing PEVAR were not uniform across all series. The technical success rate was 94 % per arterial access. Failure was unilateral in the majority (93 %) of the 133 failed PEVAR cases. The groin complication rate in PEVAR was 3.6 %; a minority (1.6 %) of these groin complications required open surgery. The groin complication rate in failed PEVAR cases converted to groin cutdown was 6.1 %. A significantly higher technical success rate was achieved when arterial access was performed via ultrasound guidance. Technical failure rate was significantly higher with larger sheath size (≥20F). CONCLUSION: The preclose technique in PEVAR has a high technical success rate and a low groin complication rate. Technical success tends to increase with ultrasound-guided arterial access and decrease with larger access. When failure occurs, it is unilateral in the majority of cases, and conversion to surgical cutdown does not appear to increase the operative risk.

Basic neuroangiography: review of technique and perioperative patient care.

Neuroangiography (NA) is an important part of diagnosis and treatment of patients with neurological disease. Although NA may be performed for diagnostic purposes, in many instances NA is performed with the intent to treat. Indications for NA range from extracranial diseases (vertebrobasilar insufficiency from subclavian steal, extracranial carotid stenosis, cavernous-carotid fistula, neck trauma, epistaxis, tumor invasion of the carotid artery, and tumor embolization) to intracranial diseases (nontraumatic subarachnoid hemorrhage, cerebral aneurysms, cerebral arteriovenous malformations, cerebral vasospasm, acute stroke, tumor embolization, and WADA test). Similar to peripheral angiography, appropriate preprocedural assessment and postprocedural care, along with understanding of anatomy, catheter technique, and disease processes, are vital to successful outcomes. This article will review the basic technique, equipment, and patient management in NA. With appropriate skill and knowledge, interventional radiologists can perform NA with safe and successful results.

Basic vascular neuroanatomy of the brain and spine: what the general interventional radiologist needs to know.

This article is intended to provide a review of clinically relevant neurovascular anatomy. A solid understanding of the vascular anatomy of the brain and spine are essential for the safe and effective performance of neurointerventional radiology. Key concepts to master include collateral pathways and anastomoses between the external and internal carotid circulation, the Circle of Willis as a route to otherwise inaccessible intracranial vascular distributions, and the origin of spinal arterial blood supply. These concepts will be highlighted using clinical angiographic examples with discussion of relevant embryology and pathology as needed.

Interventional management of vertebral body metastases.

Metastases to the vertebral column are often due to hypervascular primary tumors, the most common of which is renal cell carcinoma. Clinical symptoms attributed to vertebral body metastases include localized pain, mechanical instability of the vertebral column, and neurologic deficits resulting from mass effect. Treatment options include targeted radiotherapy, percutaneous vertebral augmentation with or without thermal ablation, and surgical resection with subsequent fusion. Overall, surgical resection of the tumor and stabilization of the vertebral column provide the best prognosis for the patient in terms of symptomatic improvement and long-term survival; however, resection of hypervascular vertebral body metastases can result in significant intraoperative blood loss that can add to the morbidity of the procedure. Preoperative embolization of hypervascular metastases of the vertebral column has been shown to significantly reduce intraoperative blood loss at the time of surgery. The goal of this manuscript is to describe the role of embolization therapy in the management of patients with vertebral body metastases.

Intra-arterial Stroke Management.

Acute ischemic stroke is a leading cause of death and the leading cause of disability in the United States. Cerebral neuronal death begins within minutes after threshold values of blood oxygen saturation are crossed. Prompt restoration of oxygenated blood flow into ischemic tissue remains the common goal of reperfusion strategies. This article provides a brief overview of acute ischemic stroke, a summary of the major intra-arterial stroke therapy trials, and comments on current training requirements for the performance of intra-arterial therapies.

Carotid artery stenting: review of technique and update of recent literature.

Stroke is the fourth leading cause of death and the number one cause of long-term disability in the United States. Carotid stenosis is an important cause of ischemic strokes, accounting for 20 to 25%. Previous studies have established carotid endarterectomy as standard of care of symptomatic patients with > 50% stenosis and asymptomatic patients with > 60% stenosis; recently, carotid artery stenting has emerged as an alternative treatment for carotid stenosis. Several studies have been published comparing carotid artery stenting with endarterectomy with mixed results. In this article, the authors discuss carotid artery stenting technique, the results from the most recent trials, and future directions.

Interventional spine procedures for management of chronic low back pain-a primer.

Chronic low back pain is a common clinical condition. Percutaneous fluoroscopic-guided interventions are safe and effective procedures for the management of chronic low back pain, which can be performed in an outpatient setting. Interventional radiologists already possess the technical skills necessary to perform these interventions effectively so that they may be incorporated into a busy outpatient practice. This article provides a basic approach to the evaluation of patients with low back pain, as well as a review of techniques used to perform the most common interventions using fluoroscopic guidance.

Catheter-based arterial sympathectomy: hypertension and beyond.

Transluminal ablation of renal artery sympathetic nerves has been shown to provide a significant and durable reduction in blood pressure with very low complication rates. Additional publications have documented improvement in insulin sensitivity, obstructive sleep apnea indices, and frequency and severity of congestive heart failure in subgroups undergoing the procedure. This technology may provide effective management of other diseases in which there is autonomic imbalance. Available data are reviewed with the intent to provoke interest within the interventional radiology community in this novel technology, which may allow minimally invasive treatment of many important chronic medical conditions.

Angiographically documented hemorrhagic conversion of a left middle cerebral artery embolic stroke during intra-arterial thrombolysis.

BACKGROUND AND PURPOSE: The clinical benefits of intra-arterial thrombolysis for ischemic stroke must be weighed against the risks, including hemorrhagic conversion. SUMMARY OF CASE: A case of angiographically documented hemorrhagic conversion of an ischemic stroke during intra-arterial thrombolysis is presented. Discussion focuses on recognition and management of risk factors for hemorrhagic conversion during performance of stroke thrombolysis. CONCLUSIONS: Recognition and modification of risk factors for hemorrhagic conversion may not prevent this complication during stroke thrombolysis. Identification of the angiographic appearance of hemorrhagic conversion should alert the interventionalist to the likelihood of a poor clinical outcome regardless of vessel patency status.

The prevalence and clinical significance of noncardiac findings on cardiac MRI.

OBJECTIVE: This study aims to evaluate the prevalence, nature, and clinical significance of noncardiac findings (NCFs) at cardiac MRI. MATERIALS AND METHODS: We retrospectively reviewed 240 consecutive, clinically indicated cardiac MRI examinations conducted over a 21-month period. All noncardiac findings (NCFs) were recorded. Those findings that were included in the report impressions were regarded as clinically important (INCF). Electronic medical records and related imaging studies were then reviewed for all patients having INCFs to determine their actual clinical significance. A finding was significant (SNCF) if it was associated with a new diagnosis, treatment, or intervention. The prevalences of findings in the neck, chest, and abdomen were determined. RESULTS: We found 162 NCFs in 104 studies (43%), of which 94 (58%) were INCFs, and 16 (10%) were SNCFs. There was at least one INCF in 65 studies (27%)--67% of which were new--and at least one SNCF in 13 studies (5%). Compared with younger patients, patients 60 years and older were much more likely to have INCFs (43% vs 17%) and SNCFs (12% vs 1%). Overall, 29% of NCFs were in the abdomen, 70% in the chest, and 1% in the neck. The most common INCFs were pleural effusion (n = 26), air-space disease or atelectasis (n = 13), and adenopathy (n = 9). Five new cases of cancer were diagnosed, including lung (n = 2), lymphoma (n = 2), and thyroid (n = 1). CONCLUSION: NCFs are commonly encountered on cardiac MRI studies, many of which are clinically relevant. Proper recognition of NCFs is critical to the comprehensive management of patients referred for cardiac MRI.

Impact of laser fiber design on outcome of endovenous ablation of lower-extremity varicose veins: results from a single practice.

The design of laser fibers used for endovenous laser ablation (EVLA) in the management of lower-extremity varicose vein disease may affect treatment success. The purpose of this investigation is to report our experience using the gold-tip NeverTouch VenaCure laser fiber (AngioDynamics, Queensbury, NY) and to compare that to our experience with standard bare-tip fibers. A retrospective chart review of 363 consecutive EVLA treatments using the gold-tip laser fiber was performed. Demographic data including patient age, sex, history of previous varicose vein stripping, vein identity, laterality, treatment length, total applied energy in joules (J), use of adjuvant sclerotherapy and ambulatory phlebectomy, treatment-related complications, and treatment failure, which was defined as recanalization of any portion of the treated vein during follow-up as assessed by duplex ultrasound examination-were entered into a spreadsheet. These data were compared with a control group of 471 EVLA treatments performed with a standard bare-tip laser fiber. Data were analyzed using independent-samples Student's t test, chi-square test, and multivariate analysis. Demographic data were similar between the two groups. Treatments with the gold-tip fiber had a failure rate of 11.1%, whereas treatment with a bare-tip fiber had a failure rate of 2.3% during a similar follow-up period. This difference was highly statistically significant (p<0.0001). Multivariate analysis showed fiber type as the most significant factor associated with treatment failure. We conclude that laser fiber design has a significant effect on treatment success in the performance of EVLA.

Use of self-expanding intracranial stents in the treatment of acute ischemic stroke.

Conventional endovascular therapy for acute ischemic stroke includes intraarterial pharmacologic thrombolysis with tissue plasminogen activator (TPA) administration with or without mechanical thrombectomy with a variety of devices. The present report describes two cases of stroke refractory to TPA administration in which successful recanalization was accomplished by the use of a self-expanding intracranial stent. Stent-assisted recanalization may be a viable option for patients with acute ischemic stroke refractory to thrombolysis or thrombectomy.

An investigation of the relationship between energy density and endovenous laser ablation success: does energy density matter?

PURPOSE: To assess the relationship between energy density and the success of endovenous laser ablation (EVLA) treatment. MATERIALS AND METHODS: A total of 586 EVLAs were performed in a period of 35 months. Retrospective chart review was performed, and data collected included the patients' age, sex, and history of venous stripping procedures, as well as the name, laterality, and length of the treated vein segment(s) and the total energy delivered. Energy density was calculated by dividing total energy delivered (in J) by the length of vein (in cm). Energy density selection was based on the treating interventionalist's preference. Ablated segments were grouped into those treated with less than 60 J/cm, 60-80 J/cm, 81-100 J/cm, and more than 100 J/cm. Failure of EVLA was defined by recanalization of any portion of the treated vein during follow-up as assessed by duplex Doppler ultrasound examination. Failure rates were compared with the chi(2) test and Wilcoxon rank-sum test. RESULTS: A total of 471 segments were included in the analysis with an average follow-up period of 5 months (range, 0.2-28.7 months). Overall, 11 failures were encountered, including four in the group treated with less than 60 J/cm (n = 109; 4%), two in the 60-80-J/cm group (n = 77; 3%), four in the 81-100-J/cm group (n = 169; 3%), and one in the group treated with more than 100 J/cm (n = 116; 1%). There was no statistically significant difference in failure rates among energy density ranges. CONCLUSION: EVLA has a low failure rate that is not affected by energy density.

Evaluation and management of patients with peripheral artery disease by interventional radiologists: current practices.

PURPOSE: Traditionally, surgeons have served as primary consultants for patients with peripheral vascular disease for whom revascularization is considered. An important component of care for patients with peripheral artery disease (PAD) is risk factor management. The present study was undertaken to determine current management practices of interventional radiologists for patients with PAD and compare them to published data for vascular surgeons. If PAD patient management practices are similar, this would support direct referral of PAD patients who are considered for revascularization from primary care doctors to interventional radiologists. MATERIALS AND METHODS: An online survey was administered to full members of the Society of Interventional Radiology with e-mail addresses on file. Filtering was done to examine and compare interactions among several responses. The margin of error for the survey was +/-2%, based on 95% CIs for the entire surveyed population (N=2,371). RESULTS: Seventy-five percent of respondents see PAD patients in ambulatory office settings. Only eight percent see themselves as the physician responsible for risk factor management, similar to reported results of vascular surgeons (10%). Other variables examined, such as frequency of inquiring about Framingham risk factors, indicate similar practices to those previously reported for vascular surgeons. CONCLUSIONS: For interventional radiologists who accept direct referrals for medical management of patients with PAD, disease management by interventional radiologists is similar to that previously reported for vascular surgeons. This supports the role of interventional radiologists who accept direct referrals of patients with PAD as primary consultants to primary care doctors.

Referrals to a dedicated cardiac MRI service: who sends what?

The purpose of this study was to retrospectively evaluate the referral patterns to the authors' cardiac magnetic resonance imaging service in its first 28 months of operation. In late November 2003, the authors' radiology practice established a cardiac magnetic resonance imaging service for a 719-bed teaching hospital and a 247-bed community hospital. Data relevant to referrals were reviewed. Between December 1, 2003, and April 1, 2006, 780 patients were imaged, 556 (71%) at the teaching hospital. Referrals came from 157 physicians in 17 different medical specialties, including adult cardiology (64%), cardiothoracic surgery (15%), pediatric cardiology (8%), internal medicine (6%), and others (7%). Overall, primary indications were function and viability evaluation (29%), aorta and valve assessment (24%), congenital heart disease (17%), arrhythmogenic right ventricular dysplasia exclusion (13%), cardiac masses (9%), pericardial disease (4%), and others (4%). Referrals for function and viability represented a much greater percentage of cases at the community hospital (53%) than at the teaching hospital (19%). The reverse was true for congenital heart disease (7% vs 21%). This study demonstrates that cardiac specialists generate the vast majority of referrals (87%) to the authors' cardiac magnetic resonance imaging service and that there are substantial differences in the referral patterns between a large teaching hospital and a smaller community hospital.