Dual-head gamma cameras operated in coincidence mode are a new approach for tumour imaging using fluorine-18 fluorodeoxyglucose (FDG). The aim of this study was to assess the diagnostic accuracy of such a camera system in comparison with a full-ring positron emission tomography (PET) system in patients with lung cancer. Twenty-seven patients (1 female, 26 males, age 62+/-9 years) with lung cancer or indeterminate pulmonary nodules were studied on the same day with a full-ring PET scanner (Siemens ECAT EXACT) and a coincidence gamma camera system (ADAC Vertex MCD). Sixty minutes after injection of 185-370 MBq FDG, a scan of the chest was performed with the full-ring system. Approximately 2 h p.i., the coincidence camera study was performed. Coincidence gamma camera (CGC) and PET images with (PETac) and without attenuation correction (PETnac) were analysed independently by two blinded observers. In addition, FDG uptake in primary tumours and involved lymph nodes was quantified relative to normal contralateral lung (T/L ratios). All primary tumours were histologically proven. The lymph node status was histologically determined in 23 patients. In four patients, no lymph node sampling was performed because of extensive disease or concurrent illnesses. In the 27 patients, 25 primary lung cancers and two metastatic lesions were histologically diagnosed. The number of coincidences per centimetre axial field of view was 3.33+/-0. 93x10(5) for the CGC and 1.09+/-0.36x10(6) for the dedicated PET system. All primary tumours (size: 4.6+/-2.6 cm) were correctly identified in the CGC and dedicated PET studies. T/L ratios were 4. 7+/-2.5 for CGC and 6.9+/-2.8 for PETnac (P <0.001). Histopathological evaluation revealed lymph node metastases in 11 of 88 sampled lymph node stations (size: 2.3+/-1.0 cm). All lymph node metastases were identified in the PETac studies, while PETnac detected 10/11 and CGC 8/11. For positive lymph nodes that were visible in CGC and PETnac studies, T/L ratios were 3.7+/-2.3 for CGC and 6.6+/-3.1 for PETnac (P=0.02). The diameters of false-negative lymph nodes in the CGC studies were 0.75, 1.5 and 2 cm. False-positive FDG uptake in lymph nodes was found in two patients with all three imaging methods. For all lesions combined, T/L ratios in CGC relative to PETnac studies decreased significantly with decreasing lesion size (r=0.62; P<0.001). In conclusion, compared with a full-ring PET system the sensitivity of CGC imaging for detection of lung cancer is limited by a lower image contrast which deteriorates with decreasing lesion size. Nevertheless, the ability of CGC imaging to detect pulmonary lesions with a diameter of at least 2 cm appears to be similar to that of a full-ring system. Both systems provide a similar specificity for the evaluation of lymph node involvement.

Experimental sutureless colonic anastomosis was evaluated under various conditions during the first 24 postoperative hours. Adaptation of large bowel segments was achieved by interrupted inverting sutures, which were removed after one hour. This short adaptation period was sufficient for fibrinous contact of bowel segments. Breaking strength of intestinal anastomosis was determined under normal conditions, in peritonitis, complete ischemia and unilateral ischemia of one bowel segment. As control parameter breaking strength of conventional anastomosis was determined under normal conditions. We obtained the following results: 1) Sutureless anastomosis exhibited significantly lower breaking strength than conventional anastomosis. 2) Sutureless anastomosis showed a significant increase in breaking strength under normal conditions after the first 6 h, on the contrary breaking strength remained at lower levels in peritonitis. 3) In complete ischemia anastomotic failure was observed even after 3 h of adaptation. Therefore breaking strength was not measurable. 4) Under unilateral ischemia breaking strength of intestinal anastomosis was significantly lower than under normal conditions.

Healing of intestinal anastomoses was found to be effective in rat, rabbit and pig even after temporary approximation by sutures for one hour. Approximation of bowel segments was achieved by interrupted inverting sutures. After one hour a fibrinous connection of inverted serosa segments was to be observed. Bursting pressure was determined on the 1st, 3rd and 7th postoperative day. There was no significant difference between sutureless and regular anastomoses. Determination of breaking strength of approximated anastomoses one hour and twenty-four hours after removal of sutures was found to be 0.19 N and 0.8 N, respectively. Extent of adhesions was similar in conventional and sutureless anastomoses. Histologic analyses revealed areas of necrosis in sutured anastomoses, whereas in sutureless anastomoses no necrosis could be detected.

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The effect of fibrin sealant on breaking strength of colonic anastomosis was evaluated in peritonitis and ischemia. (1) Under normal conditions, breaking strength of sutureless anastomosis (SLA) increased up to the 24th postoperative hour, while breaking strength of fibrin-glued anastomosis (FGA) remained on continuously low levels. (2) In peritonitis, breaking strength of FGA was significantly higher than that of SLA after 6 and 24 h. (3) In ischemia, SLA failed completely, even after temporary adaptation for more than 3 h. Breaking strength of FGA of ischemic bowel was as high as SLA under normal conditions.