Transudative vs exudative pleural effusions: differentiation using Gd-DTPA-enhanced MRI.

The aim of this study was to investigate the capability of Gd-DTPA-enhanced MRI to differentiate between exudative and transudative pleural effusions. An MRI examination was performed on 22 patients with different types of pleural effusion (10 transudative and 12 exudative effusions). T1-weighted SE images were obtained before and 20 min after administration of Gd-DTPA (0.1 mmol/kg). The degree of enhancement of pleural effusions was evaluated both by visual assessment and by quantitative analysis of images. None of 10 transudative effusions showed significative enhancement, whereas 10 of 12 exudative effusions showed enhancement (sensitivity 83 %, specificity 100 %, positive predictive value 100 %). The postcontrast signal intensity ratios (SIRs) of exudates were significantly higher than corresponding precontrast ratios (P = 0. 0109) and the postcontrast SIRs of exudates were significantly higher than those of transudates (P = 0.0300). Exudative pleural effusions show a significant enhancement following administration of Gd-DTPA. We presume that this may be caused by increased pleural permeability and more rapid passage of a large amount of Gd-DTPA from the blood into the pleural fluid in case of exudative effusions. In our limited group of patients, signal enhancement proved the presence of an exudative effusion. Absence of signal enhancement suggests a transudate, but does not exclude an exudate.

CT findings of atrophy of chest wall muscle after thoracotomy: relationship between muscles involved and type of surgery.

OBJECTIVE: Postthoracotomy atrophy of chest wall muscles results from nerve injury during surgery. After encountering patients with different patterns of chest wall muscular atrophy postthoracotomy, we performed this study to determine the relationship between type of thoracotomy and atrophic muscles as seen on CT scans. MATERIALS AND METHODS: CT scans of 58 patients who had previously undergone unilateral thoracotomy were reviewed. Forty patients had a posterolateral thoracotomy, and 18 had an anterolateral thoracotomy. In two cases, the incision extended posteriorly. Atrophy seen on CT scans was defined as a marked decrease in size or thickness of a muscle compared with the muscle on the other side. RESULTS: Atrophy of the latissimus dorsi muscle and of the inferior portion of the serratus anterior muscle was detected on CT scans in 40 patients. No atrophy was found in 16 patients. The remaining two displayed atrophy only in the serratus anterior muscle. Atrophy of the latissimus dorsi muscle and of the inferior portion of the serratus anterior muscle developed in all patients who had a posterolateral thoracotomy. Atrophy developed in only two of the 18 patients who had an anterolateral thoracotomy, and in these two, the incision had been extended posteriorly. CONCLUSION: A direct correlation was found between type of thoracotomy and site of atrophy of the chest wall muscles seen on CT scans. This finding may account for different CT appearances of the thoracic wall in patients who have had thoracic surgery.

Case report: bowel infarction with splenic air embolism: computed tomography findings.

Computed tomography (CT) is used increasingly as an early radiological examination in patients with suspected bowel infarction because it provides information about the intestinal wall, mesenteric circulation and peritoneal cavity [1, 2]. Other disorders that present with similar symptoms such as intraabdominal abscess, pancreatitis and ulcerative colitis can be excluded [3]. CT can demonstrate small amounts of air within the bowel wall, in the spleno-mesenteric-portal venous system and in the peritoneal cavity, making it possible to differentiate portal venous gas from pneumobilia. The authors describe a patient in whom a specific diagnosis of bowel infarction was made on the characteristic CT findings. Furthermore, air embolism was observed in the splenic parenchyma. This finding has not been previously reported in bowel infarction or in any other abdominal disorder.