Early Detection Of Central Lung Cancer:preliminary Study With Low-dose Spiral CT

Part 1 Analysis of tumor location in lung cancerPurpose: To assess the frequency of central bronchogenic carcinoma in all lungcancer, analyze histopathologic type and clinical stage of central lung cancer andprovide evidence for designing clinical trials of screening early lung cancer.Materials and Methods: we retrospectively reviewed the clinical records of 815inpatients with bronchogenic carcinoma between 1999～2001. According to thelocation of tumor origin, lung cancer was classified into three types, includingcenitral, peripheral and diffuse or unknown cause. Rcsults: Among 815 patientswith bronchogenic carcinoma, there were 568(69.7%) patients with history ofsmoking, male 547(96.3%), 492 patients(86.6%) older than 45 years old. Insmoking patients, there were 328(58%) patients with central lung cancer(squamous cell carcinoma 198(60%), small ce1l lung cancer 85(26%)), 202patiens with peripheral lung cancer(adenocarcinoma 118(58%), squamous cellcarcinoma54(27%)). Clinical stage of central lung cancer included 16 cases withstage Ⅰ, 67 cases with stage Ⅱ, 98 cases with stage ⅢA and 234 cases withstageⅢ/Ⅳ. Conclusion: Centhel bronchogenic carcinoma accounted for 58%of all smoking paients with lung cancer and the majority of these patients wereadvanced stage at diagnosis. We put emphasis on the early detection of centrallung cancer in design of clinical screening trial.Part 2 Visualization of segmental and subsegmental bronchi:effect of different parameters with low dose multi-slicc CTPurpose: To delineate normal subsegmenta bronchi anatomy and varation onthin-section multi-slice CT (MSCT ) and compare the effect of visualization ofbronchi with different thickness and different tube currents so as to establish theoptimal protocol in depicting segrnental and subsegmental bronchi wth low dosemulti-slice CT Method8 and Materials: (l) Thin-section MSCT images of 50volunteers were evaluated on workstation monitor' CT scans were perfOrmedwith GE Lightspeed Plus multi-slice scanner using spiral mode, l20Kv, 50mA,l5mm/rotation, 0.8s/rotation, 2.5mm collimation and pitch 6:l to produce2.5mm thick image at 2.5mm increments. (2) 90 consecutive symPtom-freevolunteers were divided into 3 groups at random. GrouP A(n=30) was scannedwith protocol l, high quality mode, l5mtn/rotation, l0mm thicAnessreconstruction, 40mAs, group B(n=30) with protocol 2, high speed mode,30mm/rotation, 5mm thickness reconstruction, 40mAs, group C(n=30) withprotocol 3, high speed mode, l5mm/rotation, 2.5mm thickness reconsttuction.Monitor evalwtion was perfOrmed by three radiologists. Rcsults: 2038subsegmental bronchi of 50 volunteers were identified, which accounted for 95%of all subsegmental bronchi. The frequencies of visualization of segmentalbronchi were 74%, 98%, l00% and that of subsegmental bronchi were 28%,65%. 95% in group A, group B and group C, respectively. Group C hassignificantly higher percentage in visualization of subsegmental bronchicompared with group A and group B (P<0.0l ), Group B with significant higherpercentage in visuaIizing segmefltal bronchi than group A (P<0.0l ).Conclusion: Low dose MSCT with pitch 6, 40mAs, 2.5mm thick reconstructionscans can enhance our ability to evaluate the abnorn1ality of the segmental andsubsegmental bronchi wall and lumen, Which has a potential role as a screeningmethod fOr patients with hemoptysis and people at high risk of lung cancer.Part 3 Early lung cancer screening: preliminary study withlow-dose spiral CTPurpose: To evaluate prevalence rate of pulmonary malignant disease detectedby low-dose spiral CT screening in People at high risk of lung cancer. MatcriaIsand methods: Low-dose MSCT scans and chest radiograPhs of 300 symptom-free volunteers from an on-going screening Study were prospectively evaluated.The study has enrolled 240 smokers, aged 45 years or older, with at least l0pack-years of cigarettC smoking and 60 individu...