Fluorine-18 fluorodeoxyglucose positron emission tomography in thyroid cancer: results of a multicentre study.

The aim of this multicentre study was to evaluate the clinical significance of fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) in differentiated thyroid carcinoma and to compare the results with both iodine-131 whole-body scintigraphy (WBS) and technetium-99m 2-methoxyisobutylisonitrile (MIBI) or thallium-201 chloride (Tl) scintigraphy. Whole-body PET imaging using FDG was performed in 222 patients: 134 with papillary tumours, 80 with follicular tumours and 8 with mixed-cell type tumours. Finally, for each case an overall clinical evaluation was done including histology, cytology, thyroglobulin level, ultrasonography, computed tomography and subsequent clinical course, to allow a comparison with functional imaging results. Sensitivity of FDG-PET was 75% and 85% for the whole patient group (n = 222) and the group with negative radioiodine scan (n = 166), respectively. Specificity was 90% in the whole patient group. Sensitivity and specificity of WBS were 50% and 99%, respectively. When the results of FDG-PET and WBS were considered in combination, tumour tissue was missed in only 7%. Sensitivity and specificity of MIBI/Tl were 53% and 92%, respectively (n = 117). We conclude that FDG-PET is a sensitive method in the follow-up of thyroid cancer which should be considered in all patients suffering from differentiated thyroid cancer with suspected recurrence and/or metastases, and particularly in those with elevated thyroglobulin values and negative WBS.

[Continuous pH registration in the coronary sinus in vivo in ischemic and normoxic lactic acidosis using an ion sensitive field effect transistor catheter]. / Kontinuierliche pH-Registrierungen im Koronarsinus in vivo bei ischämischer und normoxischer Laktazidose mittels eines ISFET-Katheters.

A new catheter with an Ion Sensitive Field Effect Transistor (ISFET) for continuous measurements of blood pH in vivo was employed. In canine heart preparations (n = 15), two catheters were positioned in the coronary sinus and in the abdominal aorta, respectively. A close agreement between pH-measurements with the pH-ISFET-sensor and the corresponding pH-determinations on blood samples by conventional means (r = 0.97; pH-range 7.15-7.50) was found. The ISFET-sensor revealed a sensitivity of 50-55 mV/pH, a long-term drift rate of 1-2 mV/h, as well as a response time shorter than 100 ms. The ISFET-sensor was sensitive for the detection of respiratory and metabolic acidosis and alkalosis (hypo-, hyperventilation, myocardial ischemia, intracoronary infusion of 0.3-M lactic acid). There was a close correlation between the changes of coronary venous pH and lactate concentrations during myocardial ischemia (r = 0.83; n = 9). During ischemic acidosis there was a drastic reduction of left ventricular dp/dtmax, whereas contractility changes during normoxic lactacidosis were moderate. The pH-decrease (pH = 7.1) was identical in both interventions. The observed data suggest that the newly developed ISFET-pH-catheter is working precisely and enables respiratory and metabolic control of the whole organism as well as of individual organs.