The use of carbon dioxide angiography for renal sympathetic denervation: a technical report.

OBJECTIVE: Hypertension is the leading attributable cause of cardiovascular mortality worldwide. Patients with hypertension have multiple comorbidities including high rates of concomitant renal disease. Current pharmacological approaches are inadequate in the treatment of resistant hypertension. Renal sympathetic denervation (RDN) has been shown to effectively treat resistant hypertension. The traditional use of iodinated contrast in RDN is contraindicated in patients with significant renal insufficiency. In patients with renal impairment, carbon dioxide (CO2) can be used as an alternative contrast material for RDN. This article describes the technical aspects of RDN using CO2 angiography. METHODS: Our centre is experienced in the innovative RDN procedure using CO2 angiography. We describe the protocol for CO2 angiography for RDN using a home-made CO2 delivery system and the Symplicity™ (Minneapolis MN 55432 USA) catheter (Medtronic) device. RESULTS: CO2 angiography is an excellent alternative to iodinated contrast for RDN procedures. CONCLUSION: CO2 angiography for RDN is a safe and effective alternative to iodinated contrast. RDN using CO2 angiography is an easy and feasible procedure that can be used in patients with renal insufficiency or iodinated contrast allergies. Advances in knowledge: There is a paucity of descriptive reports for CO2 angiography for RDN and we provide details of the optimal protocol for the procedure. In particular, we describe the use of a Symplicity Spyral™ catheter (Medtronic), which has not been reported to date for use in this procedure.

Computed tomography and magnetic resonance imaging evaluation of pericardial disease.

Pericardial diseases are commonly encountered in clinical practice and may present as an isolated process or in association with various systemic conditions. Traditionally transthoracic echocardiography (TTE) has been the method of choice for the evaluation of suspected pericardial disease but increasingly computed tomography (CT) and magnetic resonance imaging (MRI) are also being used as part of a rational multi-modality imaging approach tailored to the specific clinical scenario. This paper reviews the role of CT and MRI across the spectrum of pericardial diseases.

Multi-detector CT assessment in pulmonary hypertension: techniques, systematic approach to interpretation and key findings.

Pulmonary arterial hypertension (PAH) may be suspected based on the clinical history, physical examination and electrocardiogram findings but imaging is usually central to confirming the diagnosis, establishing a cause and guiding therapy. The diagnostic pathway of PAH involves a variety of complimentary investigations of which computed tomography pulmonary angiography (CTPA) has established a central role both in helping identify an underlying cause for PAH and assessing resulting functional compromise. In particular CTPA is considered as the gold standard technique for the diagnosis of thromboembolic disease. This article reviews the CTPA evaluation in PAH, describing CTPA techniques, a systematic approach to interpretation and spectrum of key imaging findings.

Spontaneous spinal epidural haematoma mimicking acute coronary syndrome.

Spontaneous spinal epidural hematoma (SSEH) is an acute neurological emergency which carries significant morbidity unless diagnosed and treated in a timely fashion. Some cases of SSEH are idiopathic but there is a well-recognised association with deranged coagulation and abnormalities of clotting. In recent years there has been increasing availability of novel anti-platelet agents, often prescribed in the setting of suspected acute coronary syndromes (ACS) and following percutaneous coronary interventions and these agents also present an increased risk of SSEH. We present a case of SSEH following an acute presentation with chest pain and treatment with dual anti-platelet therapy.

Radiology training in United Kingdom: current status.

Clinical radiology has always been one of the most competitive specialties in UK. Due to the increasing demand for radiology services the number of training posts in the UK has been increased. Clinical radiology training takes 5 years and requires completion of the Fellowship of Royal College of Radiologists (FRCR) exams, adequate evidence to demonstrate completion of the curriculum and successful appraisals. On completing training and receiving the Certificate for Completion of Training (CCT) a select proportion of trainees choose to embark on a fellowship program. This gives trainees the opportunity to further develop their subspecialty interest generating a high level of confidence in diagnostic and procedural skills.

MRI assessment of cardiac tumours: part 1, multiparametric imaging protocols and spectrum of appearances of histologically benign lesions.

Cardiac magnetic resonance imaging (MRI) is the reference standard technique for assessment and characterization of a suspected cardiac tumour. It provides an unrestricted field of view, high temporal resolution and non-invasive tissue characterization based on multi-parametric assessment of the chemical micro-environment. MRI exploits differences in hydrogen proton density in conjunction with T1 and T2 relaxation properties of different tissues to help differentiation normal from abnormal and benign from malignant lesions. In this article we review specific cardiac MRI techniques, tumour protocol design and the appearance of the spectrum of histologically benign tumours.

MRI assessment of cardiac tumours: part 2, spectrum of appearances of histologically malignant lesions and tumour mimics.

Cardiac magnetic resonance imaging (MRI) is the reference standard technique for assessment and characterization of a suspected cardiac tumour. It provides an unrestricted field of view, high temporal resolution and non-invasive tissue characterization based on multi-parametric assessment of the chemical micro-environment. Sarcomas account for around 95% of all primary malignant cardiac tumours with lymphoma, and primary pericardial mesothelioma making up most of the remainder of cases. By contrast cardiac metastases are much more common. In this article we review the MRI features of the spectrum of histologically malignant cardiac and pericardial tumours as well as some potential tumour mimics.

A comparative analysis of ECG-gated steady state free precession magnetic resonance imaging versus transthoracic echocardiography for evaluation of aortic root dimensions.

PURPOSE: Accurate and reproducible measurement of aortic root dimensions is essential to inform clinical decision making. Transthoracic echocardiography (TTE) is the first line test for assessment of the aortic root but has potential limitations due to its limited field of view and restricted acoustic windows. Cardiac magnetic resonance imaging (MRI) is considered the "gold standard" technique for assessment of cardiac morphology and recently MRI reference ranges for aortic root dimensions have been published. The purpose of this study was to retrospectively compare aortic root measurements obtained from TTE with those derived from cardiac MRI. MATERIALS AND METHODS: Sixty-eight patients (40 males, 28 females) who had undergone both cardiac MRI and TTE imaging within a 4-month interval (mean 62 days) were included. Steady-state-free precession MRI cine imaging was performed with an acquisition plane perpendicular to the aortic root and through the true cross sectional aortic valve plane. A cusp-commissure dimension from inside wall to inside wall in end-diastole was recorded and compared with standardized TTE derived Valsalva sinus measurements. Pearson correlation coefficients and a paired t-test were used for statistical analysis. RESULTS: Mean aortic root dimension by TTE was 3.2±0.5 cm and MRI was 3.4±0.4 cm with a Pearson correlation coefficient of >0.7. Mean difference between TTE and MRI was 0.2±0.3 (P<0.001) with MRI producing a consistently higher measure. In four patients with a dilated aortic root by MRI the TTE measurement was within the normal reference range. In patients with a dilated aortic root (n=19) the mean difference was 0.2±0.4 cm (P<0.05) with MRI consistently producing the larger measure. In patients with a non-dilated aortic root t (n=49) the mean difference was 0.2±0.3 cm (P<0.05) with MRI consistently producing the larger measure. CONCLUSIONS: There is a high level of correlation between TTE and MRI derived aortic root measurements at the Valsalva sinus level. MRI consistently measures the aortic root dimension higher than TTE which may under diagnose patients with a mildly dilated aortic root. Further investigation is required to properly integrate MRI into imaging assessment algorithms.

The role of magnetic resonance imaging in hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is the most common inheritable cardiac disorder, with an estimated prevalence of 1:500 in the general population. Most cases of HCM are phenotypically expressed in adolescence or early adulthood but age-related penetrance with certain phenotypes is increasingly recognized. Clinical manifestations of HCM are usually the result of systolic and/or diastolic dysfunction, left ventricular outflow tract (LVOT) obstruction, arrhythmias and sudden cardiac death (SCD). In recent years magnetic resonance imaging (MRI) has become established as an important tool for the evaluation of suspected HCM as it can reliably establish the diagnosis, help distinguish HCM from other causes of left ventricular hypertrophy (LVH) and identify those patients at greatest risk of SCD. This article reviews the current status of MRI in the evaluation of the HCM patient including imaging protocols, disease characterization and the emerging role of MRI for risk stratification and proband screening.

Multidetector CT assessment of partial anomalous pulmonary venous return in association with sinus venosus type atrial septal defect.

Sinus venosus defects account for 15% of all atrial septal defects. They are frequently associated with partial anomalous pulmonary venous drainage of the right superior pulmonary vein into the superior vena cava (SVC). These defects require surgical correction and accurate pre-operative imaging assessment is critical. We present a case of sinus venosus atrial septal defect in which multidetector computed tomography (MDCT) angiography identified separate sites of pulmonary venous return.

Multidetector CT angiography characterisation of Type 4 dual left anterior descending coronary artery.

Duplication of the left anterior descending (LAD) coronary artery is a rare anomaly (incidence 1%) characterized by a short LAD that terminates high in the anterior interventricular groove and a long LAD that has a proximal course outside the anterior interventricular groove and returns to the groove in its distal course. The Type 4 variant of this anomaly is extremely rare whereby a long LAD arises from the right coronary sinus with a short LAD arising from the left mainstem. We present a case of Type 4 dual LAD which was characterised with multi-detector computed tomography (CT).

Safety of an i.v. ß-adrenergic blockade protocol for heart rate optimization before coronary CT angiography.

OBJECTIVE: The purpose of this study was to assess the safety of heart rate optimization by use of ß-adrenergic blockade solely by the i.v. route before coronary CT angiography. MATERIALS AND METHODS: The records of 679 patients undergoing CT coronary angiography after receiving i.v. ß-adrenergic blockade were retrospectively analyzed. Health screening was completed before scanning, and heart rate was optimized by administration of i.v. metoprolol titrated to a maximum of 70 mg to achieve a heart rate less than 65 beats/min. RESULTS: The median i.v. dose was 20 mg (range, 5-70 mg). The 679 patients analyzed had a total of 10 complications (1.47%). Major complications, defined as not resolving with observation and analgesia alone, occurred in only three patients (0.44%). These complications included a second-degree atrioventricular block. A total of 299 patients (44.0%) needed more than 20 mg of i.v. metoprolol to achieve target heart rate. Only three patients needed the maximum i.v. dose of 70 mg metoprolol. Target heart rate was reached successfully in 666 patients (98.1%) with doses of less than 70 mg. This study did not show a statistically significant association between increasing complication frequency and increasing dose. CONCLUSION: This study showed that high doses of i.v. metoprolol can be used effectively and with a low rate of major complications to control heart rate before coronary CT angiography in correctly screened patients.

Multi-detector CT angiography of the aortic valve-Part 1: anatomy, technique and systematic approach to interpretation.

The aortic valve and adjacent structures should be routinely evaluated on all thoracic cross-sectional imaging studies. Echocardiography and magnetic resonance imaging (MRI) are the main imaging techniques used for assessment of the aortic valve and related pathology but multi-detector computed tomography (MDCT) can offer valuable complimentary information in some clinical scenarios. Radiologists should be familiar with the indications, advantages and limitations of MDCT for assessment of the aortic valve. This article reviews aortic valve anatomy and relevant terminology, technical aspects of MDCT image optimisation and describes a suggested approach to interpretation.

Multi-detector CT angiography of the aortic valve-Part 2: disease specific findings.

The aortic valve and adjacent structures should be routinely evaluated on all thoracic cross-sectional imaging studies. Echocardiography and magnetic resonance imaging (MRI) are the main imaging techniques used for assessment of the aortic valve and related pathology but multi-detector computed tomography (MDCT) can offer valuable complimentary information in some clinical scenarios. MDCT is the definite means of assessing aortic valvular calcification, acute aortic syndrome and for non-invasive assessment of the coronary arteries. MDCT also has an emerging role in the planning and follow-up of trans-catheter aortic valve replacement. This article reviews the spectrum of aortic valve disease highlighting the key MDCT imaging features.

The role of imaging in hypertensive heart disease.

Hypertensive heart disease (HHD) describes a spectrum of target organ response that includes left ventricular hypertrophy, systolic, and diastolic dysfunction. A variety of imaging techniques can be used to assess the various aspects of HHD. Echocardiography has for many years been the main imaging technique in the evaluation of HHD, but there is an increasing role for cardiovascular magnetic resonance (CMR) imaging due to its ability to provide an unrestricted field of view and noninvasive tissue characterization. This article reviews the current role of imaging for HHD with particular focus on echocardiography and CMR applications.

Assessment of right heart dilatation with magnetic resonance imaging and multidetector computed tomography angiography: spectrum of disease findings.

Right heart chamber enlargement can be caused by a diverse and heterogeneous group of conditions with highly varied clinical symptoms and signs. An appreciation of the pathophysiology, causes, and imaging features of right heart enlargement is paramount in recognizing and potentially ameliorating the development of right heart dysfunction or adverse cardiac events. Chest x-ray and transthoracic echocardiography have traditionally been, and still are, the mainstay in initial evaluation of right heart dilatation; however, recent advances in both multidetector computed tomography and cardiovascular magnetic resonance imaging now permit a comprehensive assessment of the causes and consequences of right heart dilatation.

A comparative analysis of noncontrast flow-spoiled versus contrast-enhanced magnetic resonance angiography for evaluation of peripheral arterial disease.

PURPOSE: This feasibility study aimed to obtain initial data to assess the performance of a novel noncontrast spoiled magnetic resonance (MR) angiography technique (fresh-blood imaging [FBI]) compared to gadolinium-enhanced MR (Gd-MR) angiography for evaluation of the aorto-iliac and lower extremity arteries. MATERIALS AND METHODS: Thirteen patients with suspected lower extremity arterial disease that had undergone Gd-MR angiography and FBI at the same session were randomly included in the study. FBI was performed using an ECG-gated ow-spoiled T2-weighted half-Fourier fast spin-echo sequence. For analysis, the aortoiliac and lower limb arteries were divided into 18 anatomical segments. Two blinded readers individually graded image quality of FBI and also assessed the presence and severity of any stenotic lesions. A similar analysis was performed for the Gd-MR angiography images. RESULTS: A total of 385 arterial segments were analyzed; 34 segments were excluded due to degraded image quality (1.3% of Gd- MR vs. 8% of FBI-MR angiography images). FBI-MR angiography had comparable accuracy to Gd-MR angiography for assessment of the above knee vessels with high kappa statistics (large arteries, 0.91; small arteries, 0.86) and high sensitivity (large arteries, 98.1%; small arteries, 88.6%) and specificity (large arteries, 97.2%; small arteries, 97.6%) using Gd-MR angiography as the gold standard. CONCLUSION: Initial results show good agreement between FBI-MR angiography and Gd-MR angiography in the diagnosis of peripheral arterial disease, making FBI a potential alternative in patients with renal impairment. FBI showed highest accuracy in the above knee vessels. Technological refinements are required to improve accuracy for assessing the calf and pedal vessels.

Aortic intramural haematoma: pathogenesis, clinical features and imaging evaluation.

Intramural haematoma (IMH) is a localised haemorrhage within the aortic wall. Imaging plays a central role in diagnosing IMH, differentiating it from aortic dissection (AD) and assessing for complications. Imaging is also important for prognostication and to help guide clinical decision making as a number of imaging characteristics have been correlated with increased mortality rates including location, mural thickness and aortic diameter. Multidetector CT is the leading technique for diagnosis and classification of IMH owing to speed of image acquisition, multiplanar capabilities and excellent spatial resolution. MRI is rarely used to investigate the initial presentation of IMH but is frequently used for serial follow-up studies. The clinical outcome of IMH may be favourable, with spontaneous regression over time, or it may be complicated by pericardial tamponade, aortic regurgitation and development of AD. Early surgical management is the treatment of choice for patients with Stanford type A IMH whereas most patients with Stanford type B IMH have a good short-term outcome with aggressive control of hypertension. This article reviews the pathogenesis, clinical features and complications of IMH as well as the role of advanced imaging techniques in its evaluation.