Percutaneous transfemoral repositioning of malpositioned central venous catheters

Central venous catheters inserted by blind surgical placement may not advance into a satisfactory position and may require repositioning. Malpositioning via surgical insertion is common in patients in whom central venous catheters have previously been placed, as these patients are more likely to have central venous thrombosis and distortion of central venous anatomy. This is less of a problem when catheter placement is guided by imaging; however, even when insertion is satisfactory, central venous catheters may become displaced spontaneously after insertion (Fig. 1). Repositioning can be effected by direct manipulation using guidewires or tip-deflecting wires [1, 2], by manipulation via a transfemoral venous approach [3-5], and by injection of contrast material or saline [6]. Limitations of the direct approach include (1) the number and type of maneuvers that can be performed to effect repositioning when anatomy is distorted, (2) difficulty in accessing the catheter, and (3) the risk of introducing infection. Moreover, these patients are often immunosuppressed, and there is a risk of introducing infection by exposing and directly manipulating the venous catheter. Vigorous injection of contrast material or saline may be unsuccessful for the same reasons: It seldom exerts sufficient force to reposition large-caliber central venous catheters and may cause vessel damage or rupture if injection is made into a small or thrombosed vessel. We illustrate several alternative methods for catheter repositioning via a transfemoral venous approach.

Do hydrophilic guidewires affect the technical success rates of percutaneous angioplasty?

To determine whether the use of hydrophilic guidewires has influenced the success of peripheral percutaneous transluminal angioplasty (PTA), the results of PTA performed before and after the introduction of such guidewires (end of 1989) were analyzed. Before hydrophilic guidewires became generally available, the technical success rates for iliac stenosis PTA were 96%, for femoral stenosis PTA 84%, and for femoral occlusion 78%. After the introduction of hydrophilic guidewires, technical success rates were 100% (NS), 97% (P = 0.018), and 97% (P = 0.011), respectively. A prospective study of 33 patients randomly selected for PTA of femoropopliteal occlusion using either conventional or hydrophilic guidewires was performed. In this group, the technical success rate was 14/15 in the hydrophilic group, and 18/18 in the conventional group (NS). Since the introduction of hydrophilic guidewires, the technical success rates of PTA have improved and are now approaching 100%.

Nonatherosclerotic coronary artery disease: more than just stenosis

Coronary angiography is most commonly performed to evaluate atherosclerotic coronary artery stenosis. However, it is important to be aware of the spectrum of coronary anomalies, including congenital and acquired nonatherosclerotic conditions. Potentially fatal congenital coronary anomalies may manifest at any age. If not recognized, such anomalies may prevent complete assessment of coronary anatomy in patients evaluated for atherosclerotic disease. Detection of coronary anomalies associated with congenital conditions, such as transposition of the great arteries, a single ventricle, or tetralogy of Fallot, is important prior to surgery to prevent complications and allow appropriate bypass during surgery. Acquired nonatherosclerotic coronary disease may occur as a primary abnormality or as part of a multisystem disorder and may mimic atherosclerotic disease. Although most nonstenosing coronary anomalies are uncommon or rare, they are individually important and many are treatable. Knowledge of variant coronary anatomy and the appearances of nonatherosclerotic coronary anomalies is essential for good patient care.

Steps in the evolution of extracranial time-of-flight MR angiography

Magnetic resonance (MR) angiography is not a set technique but is constantly evolving. This article illustrates changes in image quality in extracranial MR angiography that have been achieved over the past few years by the introduction of several technical developments. Images from patients examined at intervals of 12 months or more demonstrate the improvements in image quality that have resulted from these technical changes. These include bandwidth optimization for operation at 1.0 T and changes in flip angle section thickness, repetition time, and echo time. Improved image quality was assessed with objective measures of contrast-to-noise and signal-to-noise ratios. The cases illustrated show the use of MR angiography to evaluate the portal or systemic veins in patients being evaluated for liver transplantation, venous occlusion, and other venous disease. Improvements in image quality are subjectively apparent and emphasize the importance of keeping pace with technical improvements in MR angiography.

Ebstein's anomaly presenting in adulthood: the role of cine magnetic resonance imaging in diagnosis

Three adult patients with late presentation of Ebstein's anomaly were studied using MRI, including cine MRI. Spin-echo MRI demonstrated a large right atrium in each case and suggested an abnormal tricuspid valve in two. Systolic signal loss, on cine MRI, deep within the right ventricular cavity correctly indicated the presence of an abnormally positioned and incompetent tricuspid valve, and the diagnosis of Ebstein's anomaly in each patient. Selective presaturation MRI demonstrated an associated atrial septal defect in one patient. The diagnosis was confirmed by echocardiography in each case and cardiac catheterization with contrast angiography in one case. Cine MRI clearly demonstrates abnormal tricuspid valve morphology and function in Ebstein's anomaly and is a useful technique when other imaging is unclear.

Pseudoaneurysm of the common femoral vein as a late complication of right heart catheterization

Complications following venous punctures are unusual. We describe a case of a false common femoral vein aneurysm following right heart catheterization in a patient with systemic venous hypertension due to tricuspid regurgitation. The initial interpretation of the Doppler ultrasound study lead to a digital subtraction femoral arteriogram which was normal. Magnetic resonance venography demonstrated a femoral venous pseudoaneurysm.

MR angiography as the sole method in evaluating abdominal aortic aneurysms: correlation with conventional techniques and surgery

PURPOSE

To compare magnetic resonance (MR) angiography with conventional preoperative imaging techniques and surgical findings in the evaluation of abdominal aortic aneurysms (AAAs).

MATERIALS AND METHODS

MR angiography was performed in 40 patients with an AAA. Two-dimensional time-of-flight MR angiography with maximum intensity projections was compared with conventional angiography, ultrasound, computed tomography, and surgery.

RESULTS

In 18 of 20 patients, MR angiography demonstrated more extensive disease than did angiography. MR angiography depicted 41 of 43 renal arteries and seven of eight renal artery stenoses (one false-negative finding of mild stenosis) identified at angiography. When iliac arteries were imaged (30 patients), good correlation with angiography was seen in all but one patient (resulting from surgical clip artifact). Ten iliac stenoses were seen at both studies. Angiography caused underestimation of the extent of seven iliac aneurysms.

CONCLUSION

MR angiography can provide all of the necessary preoperative information for evaluation of AAA and can replace conventional angiography in many cases.

MR imaging of the thoracic aorta: comparison of spin-echo, angiographic, and breath-hold techniques

PURPOSE

To compare magnetic resonance (MR) angiography and fast MR imaging with spin-echo (SE) and non-MR imaging techniques in examination of the thoracic aorta.

MATERIALS AND METHODS

Eighty-nine patients underwent breath-hold or cine MR angiography; SE was used in 67 patients and fast MR imaging in 28. A comparison was made with non-MR imaging (transthoracic echocardiography in 49 patients, transesophageal echocardiography in 18, and arteriography in 33) findings and those from surgery or autopsy (16 patients).

RESULTS

MR angiography enabled differentiation of slow flow from thrombus, demonstrated aortic valve anatomy and aortic regurgitation, and accurately showed anatomy with only one error. It demonstrated two communications, flaps, and three branch stenoses better than SE, which produced some artifacts that mimicked thrombus or flaps. Fast MR imaging often produced artifacts or poor image quality (10 of 28 patients).

CONCLUSION

Compared with SE MR imaging, MR angiography provides additional useful anatomic and functional information concerning diseases of the thoracic aorta, usually gained only with echocardiography or arteriography.

Developments in echocardiography

Over the last 25 years, echocardiography has progressed from being an interesting technical achievement to a major cardiac diagnostic tool. Echocardiography has many advantages, including widespread availability, safety, and low cost. These features, combined with its accuracy in providing structural and functional information, have led to its introduction into many areas of cardiac diagnosis. Recent technologic developments have further increased the amount of information provided by echocardiography.

MRI of right atrial pseudomass: is it really a diagnostic problem?

OBJECTIVE

To determine whether the high proportion of patients reported to have prominence of normal right atrial structures by MRI may lead to inappropriate diagnosis of intracardiac tumors.

MATERIALS AND METHODS

One hundred forty-nine subjects were examined by spin-echo MRI: patients with cardiac (no. 40), pericardial (no. 30), or thoracic aortic disease (no. 40) and mediastinal tumor (no. 15), and normal volunteers (no. 24). Imaging was reviewed to determine the frequency of a prominent crista terminalis/Chiari network and the likelihood of misdiagnosis of cardiac tumor.

RESULTS

Prominent intraatrial structures were seen in 59% of subjects, a single prominent nodule in 36%, an intraatrial strand in 13%, and both in 10%. In no case were these findings originally or on review thought to represent a pathological mass or was it felt likely that they could reasonably be misinterpreted as such.

CONCLUSION

Normal structures within the right atrium, such as the crista terminalis and Chiari network, may be seen more commonly with MRI than with other imaging modalities. An appreciation of the frequency with which these findings are seen should prevent inappropriate misdiagnosis of pathological masses when none is present.

Mediastinal Castleman disease: MR and MRA features

Castleman disease is a rare lymphproliferative disorder that most commonly occurs in the mediastinum. The tumor is very vascular, and biopsy is dangerous. We report magnetic resonance angiography findings, to our knowledge previously undescribed, of prominent feeding vessels; this might draw attention to the possible diagnosis and avoid inappropriate biopsy.

Magnetic resonance angiography of systemic thoracic and abdominal veins

The development of MR angiography has greatly expanded the use of MR imaging for investigating the systemic veins both in the thorax and in the abdomen. With its multiplanar imaging capabilities and three-dimensional image acquisition, MR angiography is the definitive method for imaging the systemic veins in the vast majority of patients.

Magnetic resonance angiography of the thoracic aorta

The development of MR angiography techniques has improved the quality of information available from MR of the thoracic aorta. With current cine techniques and three-dimensional MR angiography, the thoracic aorta can be examined noninvasively with a high degree of accuracy.

3D image reconstruction of right subclavian artery aneurysms

OBJECTIVE

Three-dimensional (3D) image reconstruction methods allied to spiral CT (SCT) or MR angiography (MRA) are used in clarifying the anatomy of complex aortic anatomy.

MATERIALS AND METHODS

Two patients with superior mediastinal masses suggestive of aneurysms of the anomalous right subclavian artery were examined. Both patients were examined using breath-hold SCT and one by breath-hold MRA. Three-dimensional images were reconstructed using a surface rendering technique for the SCT examinations and by a maximum intensity projection technique for MRA.

RESULTS

Two cases of aneurysmal anomalous right subclavian artery were diagnosed by SCT with 3D image reconstruction. One case was also examined by MRA with 3D image reconstruction which confirmed the findings of SCT. The use of the 3D techniques clarified the complicated anatomy and avoided the need for angiography.

CONCLUSION

Two cases are illustrated of 3D imaging of complicated aortic branch anatomy due to aneurysms of anomalous right subclavian artery. Image quality was good and no further imaging by more invasive techniques was required.

Case report: unsuspected pericarditis diagnosed with gallium67 scan

Gallium67 scanning may be used to localize disease activity in pyrexia of unknown origin. In this patient the finding of unsuspected pericarditis also provided a pointer to the correct diagnosis.

Embolization in the treatment of acquired and congenital abnormalities of the heart and thorax

Embolization is well suited to the treatment of a range of vascular abnormalities found only in the thorax. This includes congenital arteriovenous fistulas or malformations affecting the chest wall and the pulmonary and coronary arteries. Acquired bronchial artery anomalies and some types of congenital heart disease are also suitable for embolization. Embolization in the thorax presents problems related to the need to work through or in the heart or to the risk to important branches of the intrathoracic aorta, such as the carotid arteries. The choice and use of different catheters and embolic materials for thoracic embolization depend on the nature and configuration of the lesion and the experience of the operator. Selection must also be based on consideration of the risk of inadvertent embolization of adjacent structures such as the spinal arteries. With embolization experience elsewhere in the body and an understanding of the particular problems presented by thoracic embolization, various important, even if uncommon, conditions can be effectively treated.

Correct positioning for cardiac angiography: insights from MRI

The recommended angiographic projections for optimally demonstrating various cardiac structures vary, and do not always achieve their aim. To determine the most appropriate radiographic projections to optimally demonstrate cardiac structures, we reviewed the orientations of major cardiac structures and the associated great vessels, as demonstrated by axial MRI. Measurements were made from 187 MRI examinations of the heart. These measurements confirmed that the optimum angiographic projections for various cardiac structures are at variance with a number of the recommended views. Recommendations for the angiographic projections most likely to provide optimum display of various cardiac structures and associated great vessels in different patient populations are presented.

Are routine chest radiographs prior to angiography of any value?

Chest radiographs are frequently requested prior to diagnostic angiography, though there is no published evidence of their clinical utility. This study was undertaken to evaluate their contribution to patient management. The routine chest radiographs obtained prior to peripheral and coronary angiography in 240 patients were prospectively reviewed for abnormalities likely to affect management. Two hundred and twenty (91.7%) examinations were performed, of which 164 were obtained within 24 h of angiography. Previous radiographs were available in 154 patients (64.2%). One hundred and sixteen radiographs were normal. There were 117 abnormalities on the radiographs of 104 patients, mainly cardiac enlargement and heart failure. No angiogram was postponed or cancelled because of abnormalities detected on a routine radiograph, although radiographic findings led to a change in the volume of contrast medium injected into dilated aortic roots in 10 patients undergoing cardiac catheterization. Pre-angiography radiographs had no effect on the practice of peripheral angiography. In only one patient were further investigations and therapy instigated because of findings, but even in this case these findings were present on previous studies. We conclude that routine pre-angiography chest radiographs are not necessary in the absence of specific clinical indications.