CT-guided pericardiocentesis.

PURPOSE: Pericardial effusion in patients who have recently undergone cardiac surgery is often trapped in compartments. CT of the pericardium provides good information about the distribution of pericardial fluid in the postoperative period after cardiac surgery. Contrary to echocardiography, CT imaging is not affected by postoperative mediastinal emphysema and pain from the wound. A method for CT-guided pericardiocentesis was developed. MATERIAL AND METHODS: CT-guided pericardiocentesis was carried out with a stereotactic device in 10 patients. The pericardium was punctured with a 0.9-mm needle and a 0.46-mm guide wire was introduced through the needle. An indwelling catheter was introduced over the guide wire and was left in the pericardium. Both the subxiphoid and parasternal approaches were used. RESULTS: CT guidance facilitated placement of an indwelling catheter into the pericardial space in positions difficult to reach in patients with postoperative pericardial compartments, i.e. near the right atrium and adjacent to the cardiac apex/left ventricle. CONCLUSION: CT-guided pericardiocentesis offers a new possibility in patients where fluoroscopically or echocardiographically guided pericardiocentesis is difficult.

A biodegradable patch used as a pericardial substitute after cardiac surgery: 6- and 24-month evaluation with CT.

Biodegradable patches made of polyhydroxybutyrate (PHB) were recently shown to limit postoperative pericardial adhesions when inserted into the pericardium in sheep. The present study was carried out to evaluate the presence of post-operative retrosternal adhesions after cardiac surgery in patients operated on with the PHB patch compared with those operated on without the insertion of such a patch. 50 patients admitted for CABG and/or valvular replacement were randomised to treatment either with pericardial closure with a patch or with the pericardium left open. In 39 of these (19 with and 20 without a PHB patch) computerised tomography was carried out six and twenty-four months postoperatively. Computerised tomography indicated a lower incidence (p < 0.05) of postoperative adhesions between the patch and the cardiac surface in the patch group, compared with the corresponding area in the non-patch group. A reduction of patch size in 27% (p = 0.003) was also seen.

Aortic motion: a potential pitfall in CT imaging of dissection in the ascending aorta.

OBJECTIVE: Artefacts complicate the diagnosis of thoracic aortic dissection by CT. Aortic compliance and cardiac motion may be responsible but the precise cause of these artefacts remains unclear. MATERIALS AND METHODS: Fifty consecutive clinical thoracic CT examinations performed on a Siemens Somatom Plus scanner (8 mm slice thickness, 1 s scan time) were reviewed (mean patient age 56 years). For each examination, the presence, position, and displacement of motion artefact from the aortic wall were noted at three ascending aortic levels. Cine ultrafast CT on 10 volunteers (mean age 49 years) was used to assess aortic motion for the same three levels (8 mm slice thickness, 50 ms scan time). Digital subtraction of consecutive cine CT allowed the position of the aortic wall throughout the cardiac cycle to be tracked. RESULTS: Curvilinear motion artefacts were seen in the ascending aorta in 17 conventional CT scans, occurring left anterior and right posterior in all but one and maximally at the aortic root (mean amplitude 3.5 mm). Ultrafast CT, however, showed no motion artefact and no significant change in aortic area with systole. Aortic motion in the sagittal-oblique plane at the ascending aorta was confirmed. CONCLUSION: Motion artefacts simulating ascending aortic dissection occur frequently on conventional CT. Their position is predictable and is related to systolic aortic motion from the left anterior to the right posterior position.

Complications of percutaneous pericardiocentesis under fluoroscopic guidance.

Complications in 352 cases of fluoroscopy-guided percutaneous pericardiocentesis accomplished through an indwelling catheter were reviewed following surgery and non-surgery. Thirteen major complications were found, namely 3 cardiac perforations, 2 cardiac arrhythmias, 4 cases of arterial bleeding, 2 cases of pneumothorax in children, one infection, and one major vagal reaction. No significant difference in complications was found between pericardiocenteses for pericardial effusions after cardiac surgery (n = 208) and those for effusions of non-surgical (n = 144) origin. Fluoroscopy-guided pericardiocentesis by the subxiphoid approach with placement of an indwelling catheter is a safe method for achieving pericardial drainage in both surgical and non-surgical effusions. Accidental cardiac perforation with a fine needle is a minor complication as long as the needle is directed towards the anterior diaphragmatic border of the right ventricle and drainage is achieved with a reliable indwelling catheter.

Pre- and postoperative CT and MR in pseudoaneurysms of the heart.

Pseudoaneurysms of the heart have a propensity to rupture and surgery is indicated. Usually in these cases diagnostic imaging is based on angiographic and/or echocardiographic studies. We have attempted to determine in pre- and postoperative studies the value of CT and ECG-gated MRI in patients with pseudoaneurysm. Seven patients with a pseudoaneurysm and/or dyskinesia of the posterolateral or diaphragmatic wall of the left ventricle were investigated with CT and/or ECG-gated MR studies, in addition to angiography, echocardiography, and radionuclide studies, prior to cardiac surgery. Postoperative follow-up studies with CT in six and MR in five patients were also carried out. Both CT and ECG-gated MRI allowed us to visualize the neck and CT also confirmed the communication between the cavities with or without demonstrating the conduit. In addition, disruption of the epicardial fat layer by the pseudoaneurysm was seen on both CT and MR, and the presence of intrapericardial adhesions was visualized on MR. Finally, CT and MRI, in postoperative follow-up studies, may indicate a myocardial discontinuity adjacent to the surgical patch.

Epicardial fat causing pitfalls in CT and MR imaging of the pericardium.

To study the complex anatomy of the pericardium and the pericardial recesses, notably the transverse sinus and the recess behind and under the common pulmonary artery, cryomicrotomy sections of 4 frozen cadaver specimens were correlated with CT and MR imaging in multiple planes. In addition, CT chest studies of 254 patients and MR chest studies from 78 patients were reviewed. Epicardial fat interposed between the transverse sinus of the pericardium and the ascending aorta was a normal finding confirmed by cryomicrotomy studies and seen by CT in 23 of 245 patients and in MR imaging in 3 of 78 patients. Epicardial fat indenting the pericardial sac below the common pulmonary artery caused an inhomogeneous signal, mimicking lymphadenopathy on coronal T1 weighted MR images in 4 patients.

CT and MR evaluation of pericardial and retrosternal adhesions after cardiac surgery.

The visibility of the pericardium as well as of the space between the dorsal aspect of the sternal surface and the pericardial surface after cardiac surgery was determined by CT and/or MR with electrocardiographic (ECG)-gated spin-echo (SE) and gradient-echo sequences. Seventeen patients who had undergone cardiac operations and who were admitted for cardiac reoperation were investigated with CT and/or MR prior to sternal reentry. Five patients were investigated with CT alone, ten with both CT and MR, and two with MR only. At reoperation, retrosternal adhesions were classified as present or absent, and intrapericardial adhesions were classified as absent, minimal, moderate, or severe. A similar classification was applied to the CT and MR findings. In 14 of 15 patients, the CT findings were in agreement with those found at operation regarding postoperative retrosternal extrapericardial adhesions in the cranial retrosternal space and in 12 of 15 in the caudal retrosternal space. Computed tomography could not detect intrapericardial adhesions. Magnetic resonance was sensitive to metal artifacts from sternal sutures in both sequences and could therefore not be used to detect postoperative retrosternal extrapericardial adhesions. On the other hand, MR with ECG-gated SE sequences confirmed intrapericardial adhesions in 44 of 57 locations.

Pericardial effusion and pericardial compartments after open heart surgery. An analysis by computed tomography and echocardiography.

Thirty-three patients with pericardial effusion after open heart surgery were investigated with computed tomography (CT). Twelve of the 33 patients also underwent echocardiography prior to pericardiocentesis. The effusions were typed according to the results of the CT investigation. Because of postoperative adhesions, typical patterns of localized pericardial effusions were found in 16 patients. The localized compartments were seen on the right and left side of the heart and around the aorta and the pulmonary artery. CT was therefore shown to be of value for selecting the approach for drainage with catheter pericardiocentesis.