Contribution of the amount of contrast media used in pulmonary CT angiography to assess the diagnostic value of CT venography; comparison of 100 and 150ml of contrast media.

AIM: To prospectively compare the vascular attenuation achieved with 100ml iohexol (350mgI/ml) 75% with that achieved with 150ml iohexol (350mgI/ml) 75% for computed tomography (CT) venography, which was performed after CT pulmonary angiography. MATERIALS AND METHODS: A total of 122 patients were included in the study. Group A, comprising 52 patients (mean age 64.8 years, mean body weight 70.8kg) received 150ml iohexol (350mgI/ml) contrast media. Group B, comprising 70 patients (mean age 61.2 years, mean body weight 71.4kg) received 100ml iohexol (350mgI/ml) contrast medium. RESULTS: Venous opacification values measured at all levels were significantly higher in group A than those in group B (p<0.001). In group B the mean HU values were between 87 and 115 and only three of the patients had HU values less than 60 at the level of femoral vein. Assuming a venous enhancement of 80HU as the cut-off value for accurate diagnosis of deep venous thrombosis, 22.8% (16/70) in group B and 7.6% (4/52; p=0.028) in group A had non-diagnostic CT venography of left femoral vein. CONCLUSION: One hundred millilitres of contrast medium with a concentration of 350mgI/ml may produce sufficient enhancement, but 150ml of contrast medium provides better accuracy for the diagnosis of deep venous thrombosis diagnosis. For better enhancement of lower extremity deep veins, the concentration of the contrast medium and the patient's body weight may also have significance.

Synchronous bilateral typical carcinoid tumors of the lung.

A 44-year-old man was admitted to our hospital with cough and sputum symptoms. After observing bilateral masses in the chest X-ray, a tomography scan of the thorax revealed bilateral tumors. Bronchoscopic biopsies were performed. The histopathological examination showed bilateral typical carcinoid tumors. A left lower lobectomy and a right upper sleeve lobectomy were carried out subsequently. No pathological lesions were observed one year after the operation.

Tracheobronchial foreign bodies in children: importance of accurate history and plain chest radiography in delayed presentation.

AIM: To evaluate the factors associated with delayed diagnosis of foreign body aspiration (FBA) in children and to compare clinical, radiological and bronchoscopic findings in the patients with suspected FBA. MATERIAL AND METHODS: The medical records of 214 children who underwent bronchoscopy for suspected FBA were reviewed. The data were analysed in three groups: the patients with negative bronchoscopy for FBA (group I), early (group II) and delayed diagnosis (group III). RESULTS: The majority of the patients with FBA were between 1 and 3 years of age. Choking episodes, coughing and decreased breath sounds were determined in a significantly higher number of the patients with FBA. The plain chest radiography revealed radio-opaque foreign bodies (FBs) in 19.7% of all patients with FBA. Emphysema was more common in children with FBA. Clinical and radiological findings of pneumonia and atelectasis were significantly more common in the groups with negative bronchoscopy and with delayed diagnosis (p < 0.01). The FBs were most frequently of vegetable origin, such as seeds and peanuts. A significant tissue reaction with inflammation was more common in the delayed cases. CONCLUSION: To prevent delayed diagnosis, characteristic symptoms, signs and radiological findings of FBA should be checked in all suspected cases. As clinical and radiological findings of FBA in delayed cases may mimic other disorders, the clinician must be aware of the likelihood of FBA. Regardless of radiological findings, bronchoscopy should be considered in patients with an appropriate history.

Changes in electrical resistivity of swine liver after occlusion and postmortem.

The resistivity of swine liver tissue was measured in vivo, during induced ischaemia and post-mortem, so that associated changes in resistivity could be quantified. Plunge electrodes, the four-terminal method and a computer-automated measurement system were used to acquire resistivities between 10Hz and 1 MHz. Liver resistivity was measured in vivo in three animals at 11 locations. At 10 Hz, resistivity was 758 +/- 170 ohm x cm. At 1 MHz, the resistivity was 250 +/- 40 ohm x cm. The resistivity time course was measured during the first 10 min after the liver blood supply in one animal had been occluded. Resistivity increased steadily during occlusion. The change in resistivity of an excised tissue sample was measured during the first 12h after excision in one animal. Resistivity increased during the first 2h by 53% at 10 Hz and by 32% at 1 MHz. After 2h, resistivity decreased, probably owing to membrane breakdown. The resistivity data were fitted to a Cole-Cole circle, from which extracellular resistance Re, intracellular resistance Ri and cell membrane capacitance Cm were estimated. Re increased during the first 2h by 95% and then decreased, suggesting an increase in extracellular volume. Cm increased during the first 4 h by 40%, possibly owing to closure of membrane channels, and then decreased, suggesting membrane breakdown. Ri stayed constant during the initial 6h and then increased.

Hydrogen bonding and dimeric self-association of 2-pyrrolidinone: an ab initio study.

Ab initio calculations on the different associated structures of 2-pyrrolidinone with water and with itself were carried out using 3-21G and 6-31G* basis sets at the Hartree-Fock level, including electron correlation using second-order Møller-Plesset perturbation theory. The calculated free energy changes for the intermolecular hydrogen bonded dimer and hydrated species indicated that the molecular systems with cyclic dimerization and association with two water molecules are dominant. The results are compared to the available experimental data in the literature.