Abstracts/L.totg Gzncer 14 (19%) 377-408 393

demonstration of tumoural ACTH secretion, the levels of ACTH and l3- lipotrope hormone remained high suggesting lymph node and/or pulmonary metastasis. This observation emphasizes the long clinical course of carcinoid turnours despite their malignancy and the unusual response to the dexamethasone test.

Evaluation of solitary pulmonary nodules with dynamic contrast-enhanced MR imaging - A promising technique? Hittmair K, Bckersberger F, Klepetko W, Helbich T, Herold CJ. AKH, Univ.-Klinik F. Radiodiagnostik, Waehringer Guertel 18-20, A-1050 Vimna. Magn Reson Imaging 1995;13:923-33.

The evaluation of a solitary pulmonary nodule (SPN) is one of the mostfrequeatlyeacounteredchaUengesinthoracicrPdiology.Inaddition to a ‘state-of-the-art’ evaluation of SPNs with CT and biopsy techniques, recently theassessment ofthe enhancement characteristicswith iodinixed contrast agents has shown its potential to improve the characterization of SPNs. We investigated whether dynamic contrast-enhanced MRI is suitable to assess the degree and kinetics of MR contrast enhancement and whether this technique could help in the noninvasive specification of SPNs. We studied prospectively 21 patients with SPNs. T,-weighted and proton density-weighted spoiled gradient-echo breath-hold images (2D-FLASH) were obtained before and after the administration of Gd- DTPAinastandarddosageofO.1 mmol/kgbodyweight.Themaximum enhancement and the initial velocity of contrast uptake were assessed and correlated with pathohistological findings. To quantify contrast enhancement, we used the relative signal intensity increase (S(rel)) and the recently introduced enhancement factor (EF) and contrast uptake equivalent (CE). Dynamic contrast-enhanced MRI proved to be well suited for the assessment of the contrast enhancement characteristics of SPNs. Significant differences were found in the degree and kinetics of contrast enhancement for specific types ofnodules. Malignant neoplastic SPNs enhanced stronger and faster than benign neoplastic SPNs. The strongest and fastest enhancement, however, was found in a benign type of nodules where histology revesled inflammatory/fibrous lesions. These differences in contrast enhancement between the different pathohistological groups were more significant when EF and CE rather than S(rel) was used for the quantification of contrast enhancement. The results of this study indicate a potential role for dynamic contrast- enhanced MRI in the preoperative noninvasive evaluation ofSPNs using EF and CE as contrast uptake assessment parameters.

Multiplanar display of spiral CT data of the pulmonary hila in patients with lung cancer. Preliminary observations Padhani AR, Fishman EK, Heitmiller RF, Wang K-P, Wheeler JH, Kuhlman JE. Department of Rudiology, lhe Johns Hopkins Hospital, 6OON. WolfeStreet, Baltimore. MD21287. Clin Imaging 1995; 19:252- 7.

Spiral or helical computed tomography (q-generated multiplanar reconstluctionswereusediatheradiological assessmentofthepulmonary hila in patients with central lung cancer. Twelve patients with non- small-cell lung cancer and hilar abnormalities were examined with contrast-enhanced spiral CT. Studies were performed on a Siemens Somatom S or Plus-S scanner using either a 24- or 32-second spiral. The study volume was from the arch of the aorta to the inferior pulmonary veins done in a single breath-hold, using 4-mm collimation, and reconstructed at 2-mm intervals. We assessed the quality of vascular enhancement and of multiplanar reconstructions. Bronchoscopic, surgical, and pathological findings were correlated. Excellent vascular opacification and goodquality reconstructions were obtained in all patients. No interscan motion was detected. No problems were encountered with the breathholding technique or in the reconstruction of images, even in patients with poor respiratory function. Multiplanar reconstructions were uselid for the evaluation of mediastinal including

vascular and airways invasion, for optimal definition of lymph node groups, for the planning of bronchoscopically guided biopsy, aa well as forendobronchoscopic laser coagulation therapy and surgical treatment. Spiral CT-generated multiplanar reconstructions of the hila are helpful for staging, solving problems, guiding bronchoscopy, and planning surgery. Even patients with limited respiratory reserve can successfully complete the examination.

Clinical characteristics of synchronous multiple lung cancer associated with idiopathic pulmonary tibrosis: A review of Japanese cases Mixushima Y, Kobayashi M. 1st Department of Internal Medicine, Toyama Medical/Pharmaceutical Univ., 2630 Sugitani, Toyama 930 01. Chest 1995; 108:1272-7.

To define the clinical characteristics of multiple lung cancer (LC) associated with idiopathic pulmonary fibrosis (IPF), we reviewed 154 LC patients associated with IPF: 23 patients with synchronous multiple LC (IPF- multiple LC group) and 131 with single LC (IPF-single LC group), and these were compared with 4,931 patients with LC from 1975 to 1977 in Japan (whole LC group). In the IPF-single and IPF- multiple LC groups, most tumors were observed in male patients (91% and 96%), smokers (94% and lOO%), and in peripheral regions of the lung (91 R and 98%). The incidence of occmrence in the lower lobes, where a fibrotic shadow was prominent, was significantly higher in the IPF-LCgroups(%% and6746) thanforthewholeLCgroup(3796). The distribution of histologic types in the IPF-single LC group was similar to that of the whole LC group. However, the incidence of small cell carcinoma was significantly higher in the IPF-multiple LC group (33 5%) than for the IPF- single LC (14%) and whole LC (12 96) groups. These results indicate that the featmea characteristic to synchronous multiple LC in patients with IPF are as follows: (I) male patients: (2) smokers; (3) small cell carcinoma histologic type; (4) lower lobes; and (5) peripheral type, all of which show a high rate of occurrence.

Cost-effectiveness of head CT in patients with lung cancer without clinical evidence of metastases Colice GL, Birkmeyer JD, Black WC, Littenberg B, Silvestri G. Department of Medicine, Evaluative Clin. Sri. Program Center, Dartmouth-Hitchcock Medical Center. Lebanon, NH. Chest 1995;108:1264-71.

Objective: To estimate the cost-effectiveness of CT for detecting brain lesions in patients with lung cancer without clinical evidence of metastases. Design: Decision analysis model comparing two different strategies for detecting brain metestases: brain CT routinely (CT-first) or brain CT only when patients develop nemologic signs and/or symptoms (mdeferred). Patients: Hypothetical cohort ofpatients with long cancer with an unremarkable screening clinical evaluation for metastases. Measurements: Net costs are calculated as the difference in costs between the two limbs of the decision tree. Net benefits are expressed as the difference in calculated years of life expectancy between the two strategies. Net costs are divided by net benefits, yielding the marginal cost per quality adjusted year of added life expectancy (UQALY) for the CT-first strategy. Results: In the baseline analysis, the ClQALY for the CT-first strategy is about $70,090. Improving the clinical evaluation as a screen for detecting brain metastases markedly increases the UQALY. Increasing the cost ofbrain CT magnifies this effect. More effective treatment for asymptomatic brain metastasesandbetteraccuracyofCTfor identiljingresectableand unresectable brain metastasea lower ClQALY. Conclusions: Although a threshold cost-effectiveness has not been defined for identifying ‘cost- effective’ diagnostic procedures, the marginal C/QALY of the CT-first strategyissubstantiallyhigherthanmanyacceptedmedictd interventions.