Biomedical subjects

D Wormanns

Publications and source records attributed to D Wormanns.

At least 19 recordsLinked to original sources

PubMed2006

Tumor staging using whole-body high-resolution 16-channel PET-CT: does additional low-dose chest CT in inspiration improve the detection of solitary pulmonary nodules?

For optimal image fusion between CT and F-18-FDG-PET, the acquisition of CT images is performed in mild expiratory suspension, which might compromise the detection of lung metastases. This study aimed at evaluating the influence of expiration on the detection of solitary pulmonary nodules (SPN) and at assessing if additional inspiratory low-dose CT (I-LDCT) of the chest can improve the detection of potential lung metastases performing whole-body 16-channel PET-CT. Sixty-six patients with malignant tumors underwent PET-CT: contrast-enhanced CT was acquired during mild expiration and was used for fusion with PET images; additionally, chest I-LDCT was performed at deep inspiration. Two radiologists reported all SPN detected at I-LDCT and the expiratory CT scan independently. Overall, 53% of 128 SPN (mean: 3.8+/-0.2 mm) were detected at both respiratory states: 51 SPN only at I-LDCT, and 9 nodules only at expiratory CT. Of the SPN, 117/128 were classified as certain; 45 of those were additionally detected at I-LDCT, and 6 nodules at expiratory CT. A 100% detection rate was reached in SPN >4 mm at I-LDCT versus >8 mm at expiratory CT (all P<0.001). Additional I-LDCT of the chest significantly improves the detection of SPN at whole-body F-18-FDG-PET-CT and thus is recommended as part of the standard protocol for oncological patients.

Adult↗

PubMed2006

[CT-based software-supported prediction of the postoperative lung function after partial resection of the lung].

PURPOSE: The predicted postoperative forced exspiratory volume in one second (FEV (1)) is an important functional factor for predicting the operability of patients with bronchial carcinoma. A software tool that uses a preoperative chest MSCT and pulmonary function test (PFT) for largely automated prediction of the FEV (1) was evaluated. MATERIALS AND METHODS: Fifteen patients with surgically treated lung cancer were examined with a preoperative chest MSCT (1.25 mm slice thickness, 0.8 mm reconstruction increment) and PFT before and after surgery. CT scans were analyzed by the prototype software MeVisPulmo (MeVis gGmbH, Bremen) that predicted the postoperative FEV (1) as a percentage of the preoperative values measured by PFT. The automated segmentation and volumetry of lung lobes were performed either without or with minimal user interaction. Patients underwent lobectomy in twelve cases (6 upper lobes, 1 middle lobe, 5 lower lobes) and pneumectomy in three cases. The predicted FEV (1) values were compared to the observed postoperative values as a standard of reference. The additional functional parameters "total lung capacity" (TLC) and "forced vital capacity" (FVC) were compared to the FEV (1) results. RESULTS: Automated calculation of predicted postoperative lung function was successful in all cases. Due to an implausible PFT, two of the 15 patients were excluded from the collective. A mean postoperative FEV (1) value of 75 % (SD +/- 12 %) of the preoperative FEV (1) was calculated and 74 % (SD +/- 12 %) was actually measured. The deviations of the predicted value from the measured postoperative FEV (1) ranged between - 289 ml (-12 % of the measured postoperative FEV (1)) and + 294 ml (+ 15 % of the postoperative FEV (1)). The mean deviation (absolute value) was 137 +/- 77 ml/s. This corresponds to 7 +/- 3 % of the measured postoperative FEV (1). Bland-Altman-Statistics showed the 95 % "limits of agreement" for the predicted FEV (1) values to be between - 341 ml and + 301 ml, corresponding to - 17.5 % and + 15.8 of the measured postoperative FEV (1) value. Analysis of the TLC and FVC yielded similar results. CONCLUSION: In the present pilot study the software-assisted prediction of the postoperative FEV (1) using a preoperative MSCT and pulmonary function test corresponded satisfactorily with the observed postoperative values. The introduced approach may make it possible to obtain additional information for the prediction of functional operability prior to performing lung cancer surgery.

Adenocarcinoma↗

PubMed2005

Correlation between respiration-induced thoracic expansion and a shift of central structures.

The fusion of computed tomography (CT) and positron emission tomography (PET) may improve diagnostic accuracy, but is limited by different breathing protocols. This study aimed at quantifying respiration-induced alignment errors. PET-CT was acquired in 24 patients. Contrast-enhanced whole-body CT was obtained in a single breath hold in the expiratory state of a normal breathing cycle. An inspiratory low-dose CT of the thorax was acquired in the same session, and comparison of the two CT scans was used to assess the potential mismatch of PET and CT fusion. The largest craniocaudal expansion was found in the area of the diaphragm. A considerable sagittal expansion was found in the anterior parts of the lungs. Central tracheo-bronchial structures were displaced during inspiration mainly in the anterior and caudal directions. The craniocaudal shift of central structures showed a linear correlation with the diaphragmatic expansion, whereas the sagittal shift correlated with the sagittal pleural expansion. There was, however, no correlation between craniocaudal and sagittal respiratory motion. Alignment errors are most severe in the base of the lung, but central structures are affected, too. Understanding of the main vectors of respiratory motion may help in image interpretation when PET and CT are acquired separately.

Artifacts↗

PubMed2005

Resolving small pulmonary nodules: CT features.

Our aim was to analyse the CT morphology of resolving nodules over time in order seek morphologic features helpful in initial nodule classification. The imaging characteristics of 133 consecutive resolving pulmonary nodules detected in 56 subjects in a screening trial for early lung cancer with low-dose CT were retrospectively reviewed by two readers in consensus. Nodule size ranged from 2 to 28 mm, with a mean diameter of 5.9 mm. The maximum diameter of resolving nodules was < or =5 mm in 71/133 (53%), 6-10 mm in 52/133 (39%), and >10 mm in 10/133 (8%). Their location was mainly peripheral, with a mean distance to the costal pleura of 10 mm. There was no lobe predominance of nodules. In 85% (113/133) of cases the nodules were solid, 77% (103/133) were well-defined, and 73% (97/133) were non-lobulated. Eighty percent (107/133) resolved completely within 14-1,671 (mean 492) days, 20% (26/133) resolved incompletely with residual abnormalities within 51-1,777 (mean 613) days. Resolving pulmonary nodules were mostly < or =10 mm, peripherally located, solid, well-defined, and non-lobulated. Most resolve completely within a variable interval ranging from several days to years.

Adult↗

PubMed2005

Staging in childhood lymphoma: differences between FDG-PET and CT.

AIM: The clinical value of positron emission tomography using fluorine-18 fluoro-deoxy-glucose (FDG-PET) in the staging of adult lymphoma has been shown in many studies. However, there are only few data regarding childhood lymphoma. The purpose of this retrospective study was to compare the staging of childhood lymphoma using FDG-PET and the established computed tomography (CT). METHOD: Whole-body FDG-PET was performed in 25 children with histologically proven Hodgkin's disease (n = 18) and non-Hodgkin's lymphoma (n = 7) using a dedicated PET. The findings were compared with the CT results. Both examinations, FDG-PET and CT, were assessed by two experienced physicians. In each patient, 30 regions were analysed (22 nodal, 8 extranodal). Each region was assessed using a five value scale (definitely/probably positive, equivocal, probably/definitely negative). RESULTS: 662 regions (470 nodal, 192 extranodal) were compared. 91 regions (81 nodal, 10 extranodal; 14%) were concordant positive and 517 regions (347 nodal, 170 extranodal; 78%) were concordant negative. In 47 regions, 48 discordant findings (7%) were described: 27 findings (22 nodal, 5 extranodal) were positive using FDG-PET and negative using CT whereas 21 findings (17 nodal, 4 extranodal) were positive using CT and negative using PET. A total of 7 regions (1%) were judged equivocal in one imaging modality (1 FDG-PET, 6 CT). Using FDG-PET as compared to CT, resulted in a higher staging in 4 of 25 patients and in a lower staging in 2 of 25 patients. CONCLUSION: Staging of childhood lymphoma using FDGPET shows differences compared with CT resulting in a different staging in 6 of 25 patients. Prospective studies are required to evaluate the impact of these discrepancies on the clinical management of pediatric patients.

Adolescent↗

PubMed2004

[Clinical evaluation of a software for automated localization of lung nodules at follow-up CT examinations].

PURPOSE: To evaluate a software algorithm for automated localization of pulmonary nodules at follow-up CT examinations of the chest and to determine factors influencing the rate of correctly matched nodules. MATERIALS AND METHODS: The "real-time automatic matching" (RAM) algorithm (Siemens LungCare trade mark software) was applied to 22 follow-up multirow-detector CT (MDCT) examinations in 11 patients (Siemens Somatom VolumeZoom, tube voltage 120 kVp; effective tube current 20 mAs (n = 18) or 100 mAs (n = 4); 4 x 1 mm detector configuration, 1.25 mm slice thickness; 0.8 mm reconstruction increment; standard lung kernel B50f) with a total of 190 lung nodules (mean diameter 6.7 +/- 3.5 mm, range 2 - 17 mm). The following nodule features were recorded: diameter, edge definition (well- or ill-defined), location (upper, middle or lower third; central or peripheral; right or left lung) and inspiration level (considered identical if the difference of diaphragm-apex distance between baseline and follow-up examination was < 5 %, otherwise it was considered different). A nodule was regarded as correctly localized if the marking box drawn by the software was visible on at least one slice together with the nodule and the center of the nodule was located inside the marking box. chi(2)-test was used to describe influence of nodule features on detection rate. Influence of nodule size was assessed using Mann-Whitney-U-Test. RESULTS: RAM correctly located 164 of 190 of all lung nodules (86.3 %). Detection rate did not depend on nodule location (left vs. right lung: p = 0.48; upper vs. middle vs. lower third: p = 0.96; peripheral vs. central: p = 0.47) or diameter (p = 0.30). Influence of inspiration level was highly significant (p < 0.001): nodules were detected in 100 % (146/146) for identical inspiration levels and in 40.9 % (18/44) for different inspiration levels. The observation of a significant better localization of ill-defined nodules (p = 0.028) corresponds to a statistical artifact due to the inhomogeneous distributions of this specific feature in our data. CONCLUSION: RAM is a valuable tool for follow-up of lung nodules at CT. Only very different inspiration levels influenced detection rate.

Algorithms↗

PubMed2004

Diagnostic performance of a commercially available computer-aided diagnosis system for automatic detection of pulmonary nodules: comparison with single and double reading.

OBJECTIVE: To assess the diagnostic performance of a commercially available computer-aided diagnosis (CAD) system for automatic detection of pulmonary nodules with multi-row detector CT scans compared to single and double reading by radiologists. MATERIALS AND METHODS: A CAD system for automatic nodule detection (Siemens LungCare NEV VB10) was applied to four-detector row low-dose CT (LDCT) performed on nine patients with pulmonary metastases and compared to the findings of three radiologists. A standard-dose CT (SDCT) was acquired simultaneously and used for establishing the reference data base. The study design was approved by the Institutional Review Board and the appropriate German authorities. The reference data base consisted of 457 nodules (mean size 3.9 +/- 3.1 mm) and was established by fusion of the sets of nodules detected by three radiologists independently reading LDCT and SDCT and by CAD. An independent radiologist used thin slices to eliminate false positive findings from the reference base. RESULTS: An average sensitivity of 54 % (range 51 % to 55 %) was observed for single reading by one radiologist. CAD demonstrated a similar sensitivity of 55 %. Double reading by two radiologists increased the sensitivity to an average of 67 % (range 67 % to 68 %). The difference to single reading was significant (p < 0.001). CAD as second opinion after single reading increased the sensitivity to 79 % (range 77 % to 81 %), which proved to be significantly better than double reading (p < 0.001). CAD produced more false positive results (7.2 %) than human readers but it was acceptable in clinical routine. CONCLUSION: Double reading with CAD as second reader offered a significantly increased sensitivity compared to conventional double reading. Thus, CAD is a valuable tool for the detection of pulmonary nodules and should be used as second opinion.

Adult↗

PubMed2003

Lung cancer screening with low-dose CT.

Screening for lung cancer is hoped to reduce mortality from this common tumour, which is characterised by a dismal overall survival, relatively well defined risk groups (mainly heavy cigarette smokers and workers exposed to asbestos) and a lack of early symptoms. In the past studies using sputum cytology and chest radiography have failed to demonstrate any reduction in lung cancer mortality through screening. One of the reasons is probably the relatively poor sensitivity of both these tests in early tumours. Low radiation dose computed tomography (CT) has been shown to have a much higher sensitivity for small pulmonary nodules, which are believed to be the most common presentation of early lung cancer. As, however, small pulmonary nodules are common and most are not malignant, non-invasive diagnostic algorithms are required to correctly classify the detected lesions and avoid invasive procedures in benign nodules. Nodule density, size and the demonstration of growth at follow-up have been shown to be useful in this respect and may in the future be supplemented by contrast-enhanced CT and positron emission tomography. Based on these diagnostic algorithms preliminary studies of low-dose CT in heavy smokers have demonstrated a high proportion of asymptomatic, early, resectable cancers with good survival. As, however, several biases could explain these findings in the absence of the ultimate goal of cancer screening, i.e. mortality reduction, most researchers believe that randomised controlled trials including several 10000 subjects are required to demonstrate a possible mortality reduction. Only then general recommendations to screen individuals at risk of lung cancer with low-dose CT should be made. It can be hoped that international cooperation will succeed in providing results as early as possible.

Humans↗

PubMed2002

[Early lung cancer detection with low-dose CT: an update].

Lung cancer is the leading cause of death from malignancy. Due to a lack of early symptoms patients usually undergo therapy at advanced tumor stages when prognosis is poor. Feasibility studies of low-dose spiral CT screening of heavy smokers have shown that many small, resectable lung cancers can be diagnosed at early stages using simple diagnostic algorithms based on size and attenuation of detected pulmonary nodules with a small proportion of invasive procedures for benign lesions. Preliminary results of repeat screening confirms small size and favourable stage distribution of detected cancers, using even simpler diagnostic algorithms: additional diagnostic procedures are only required in new or growing nodules whereas follow-up with low-dose CT is sufficient in nodules that appear unchanged to exclude slow growth. However, mortality reduction by lung cancer screening with low-dose CT has yet to be demonstrated. Several randomised controlled trials are under way to assess possible mortality reduction by comparison of mortalities in a screening group and a control group. It is hoped that through international cooperation data from these trials can be pooled to allow for statistically significant conclusions as early as possible.

Aged↗

PubMed2002

[Selenium-based digital radiography of the cervical spine: comparison with screen-film radiography for the depiction of anatomic details].

PURPOSE: To compare selenium-based digital radiography with conventional screen-film radiography of the cervical spine. MATERIALS AND METHODS: In a prospective study X-ray images of the cervical spine were obtained in 25 patients using selenium- based digital radiography and conventional screen-film radiography. All images were clinically indicated. Selenium-based digital radiography and conventional screen-film radiography were used in a randomized order. Four radiologists independently evaluated all 50 examinations for the visibility of 76 anatomic details according to a five-level confidence scale (1 = not visible, 5 = very good visibility). From the evaluation of these anatomic details scores for the upper and middle cervical spine, the cervicothoracic junction and the cervical soft tissues were calculated. The scores for selenium-based digital radiography and conventional screen-film radiography were compared using Wilcoxon's signed rank test. RESULTS: From a total of 15,200 observations (608 per patient) the following scores were calculated for selenium-based digital radiography and for screen-film radiography, respectively: Upper cervical spine 3.88 and 3.94; middle cervical spine 4.60 and 4.48; cervico-thoracic junction 3.64 and 2.62; cervical soft tissue 4.47 and 3.46. The differences between the last two scores were statistically significant (p < 0.05). CONCLUSION: The use of selenium-based digital radiography is superior to conventional screen-film radiography in the depiction of anatomic details of the cervicothoracic junction and the cervical soft tissues.

Cervical Vertebrae↗

PubMed2002

[Early recognition of bronchial carcinoma with computerized tomography].

Bronchial carcinoma is the most common cause of tumor induced death worldwide. Because of the lack of clinical symptoms and signs the diagnosis of this tumor is generally established in advanced stages. With computed tomography (CT) pulmonary nodules can be detected with high sensitivity. Nodules are, because they are surrounded by aerated lung tissue, high-contrast objects and can be investigated with low-dose computed tomography technique. The reduction of mortality is the central issue in the ongoing discussion about early diagnosis of bronchial carcinoma with computed tomography. To date, no medical society or governmental body has expressed recommendations because randomized controlled trials have not been performed yet. It is expected that such trials are started in the near future in the USA and in several European countries.

Carcinoma, Bronchogenic↗

PubMed2001

[Bronchial carcinoma screening with low dosage CT. Current status].

Lung cancer is the most common cause of death from malignancy. It is characterized by a favourable prognosis when treated in early stages and a poor prognosis in advanced stages. Populations at risk are relatively well defined, i.e. heavy smokers and workers exposed to asbestos and radon. Therefore, early detection using diagnostic techniques promises reduction of mortality from this tumor. Previous studies using chest radiography and sputum cytology were, however, disappointing due to poor sensitivity of these tests for early tumor stages. The new technique of low-dose computed tomography provides both high sensitivity for small tumors and a comfortable examination. As small benign pulmonary nodules are common reliable non-invasive diagnostic algorithms are required for classification of nodules. Preliminary studies using low-dose CT screening in smokers have provided promising results. Prior to a wide application of the technique in clinical routine more data are required as to inclusion criteria, examination intervals and the effect of screening on mortality reduction.

Carcinoma, Bronchogenic↗

PubMed2001

Detection of pulmonary nodules at spiral CT: comparison of maximum intensity projection sliding slabs and single-image reporting.

The aim of this study was to compare numbers of pulmonary nodules detected with maximum intensity projections using a slab thickness of 15 mm (MIP 15) and 30 mm (MIP 30) with single image (SI) presentation of chest CT scans. Two readers reviewed MIP 15, MIP 30, and SI presentations of 10-mm (n = 8) and 5-mm collimation (n = 10) helical CT scans and recorded size, location, and diagnostic confidence (definite, probable) of pulmonary nodules. Readers 1 and 2 recorded more nodules with MIP 15 than with SI: 10-mm collimation, 77/64 and 60/56; 5-mm collimation, 64/60 and 40/36; and more "definite" nodules (10-mm collimation: 68/57 and 51/42; 5-mm collimation: 43/36 and 34/30). MIP 15 also detected more nodules than MIP 30 at 10-mm collimation: 77/72 and 60/50; with no major differences at 5-mm collimation: 64/66 and 40/38; and more "definite" nodules (10-mm collimation: 68/58 and 51/36; 5-mm collimation: 43/39 and 34/29). There were only minor differences between SI and MIP 30. Reading time and image number per study were reduced with MIP presentations by a factor of 1.4-5.3. There were no significant differences in the number of nodules detected with SI, MIP 15, and MIP 30, but MIP presentation reduced reporting time and filming cost when compared with SI reporting. For detection of nodules MIP 15 was slightly superior to MIP 30.

Adolescent↗

PubMed2001

Pulmonary manifestations of Hodgkin's disease: radiographic and CT findings.

The aim of this study was to assess the radiological and CT findings in patients with pulmonary Hodgkin's disease and to analyse to what extent CT provides more diagnostic information. In 37 patients with 41 episodes of pulmonary manifestation of Hodgkin's disease (histological diagnosis: 11, clinical diagnosis: 30) 39 radiographs and 33 CT scans were analysed by two readers in consensus. Pulmonary nodules were recorded in 77% of radiographs (CXR) and 88% of CT scans. Nodules were multiple in 67% (CXR) and 86% (CT) and bilateral in 43% (CXR) and 66% (CT) of cases, respectively. Nodule size ranged from 2 to 100 mm. Of the nodules, 83% at radiography and CT, respectively, were < or =30 mm, and again 83% at radiography and CT, respectively, were irregularly marginated. Diffuse infiltration with and without nodules was less common. With pulmonary manifestations at initial diagnosis of Hodgkin's disease there was always hilar or mediastinal lymphadenopathy. Of 20 episodes, in which radiograph and CT had been obtained within 8 days, CT demonstrated pulmonary involvement when chest radiography was normal in 3 cases and demonstrated more lesions in 12 cases. The typical appearance of pulmonary HD consisted of multiple, irregularly marginated pulmonary nodules. Diffuse infiltration was less common. Computed tomography was superior to radiography not only in characterization of lesions but could also demonstrate pulmonary involvement when the radiograph was normal and should, therefore, be used liberally in addition to radiography.

Adolescent↗

PubMed2001

Low-dose CT: new tool for screening lung cancer?

Lung cancer is the leading cause of death from malignant tumours as it is very common and has a poor prognosis at advanced tumour stages. Prognosis could be improved by treatment at early stages. As these stages are usually asymptomatic, a diagnostic test that would allow detection of early tumour stages in a population at risk could potentially reduce mortality from lung cancer. Previous approaches using chest radiography and sputum cytology in smokers have been disappointing. Fluorescent bronchoscopy and molecular markers are not yet applicable in clinical routine. Because of its high sensitivity for small pulmonary nodules, which are the most common manifestation of early lung cancer, CT appears suitable as a screening test. Low-dose examination parameters can and should be used for this purpose. From clinical practice it is well known that chest CT often demonstrates small pulmonary nodules, which do not represent lung cancer. Therefore, non-invasive diagnostic algorithms are required to avoid unnecessary biopsies in benign lesions. In preliminary studies of low-dose CT using algorithms based on size and density of detected nodules a large proportion of asymptomatic lung cancers and a large proportion of early, resectable tumour stages were found with a small proportion of invasive procedures for benign nodules. Before this technology can be recommended for broad application, however, further information is required regarding appropriate inclusion criteria (smoking habits, age groups) and screening intervals. Most importantly, further data are required to clarify whether lung cancer screening using low-dose CT can actually reduce mortality from lung cancer.

Diagnosis, Differential↗

PubMed2001

Abdominal spiral CT in children: which radiation exposure is required?

We decided to test to what extent dose reduction is possible in abdominal spiral computed tomography (CT) in young children without loss of anatomic diagnostic information. A retrospective study was performed of 30 abdominal CT examinations of children aged 3 months to 7 years. These were divided into two groups: group A with reduced radiation exposure (tube current 50 mA, CT dose index CTDIFDA < or =0.83 mGy) and group B with standard radiation exposure (tube current > or =100 mA, CTDIFDA > or =1.66 mGy). Image quality was assessed using a four-part scale ('excellent', 'good', 'sufficient', 'poor') on visual image impression and visibility of 32 anatomical details. Five experienced radiologists read the CT scans independently who were blinded to the examination parameters. Differences in ranked data were evaluated with Wilcoxon's rank sum test. No difference between groups A and B was observed in visual image impression. Detail visibility was significantly lower in group A, but the differences were limited to right upper quadrant structures (portal vein, common bile duct, pancreatic head, adrenals) and to arterial branches. Significant differences in visibility rated as 'poor' were only found for the hepatic, splenic and renal arteries; all other structures showed no difference between groups A and B. A protocol with reduced radiation exposure (50 mA, CTDIFDA < or =0.83 mGy) allowed the demonstration of most anatomic structures in abdominal spiral CT in young children. For the precise demonstration of small details (e.g. structures of the right upper quadrant), a protocol with standard radiation exposure (> or =100 mAs) was superior.

Child↗

PubMed2001

[Radiologic screening for lung cancer: present status and future perspectives].

Radiologic screening for lung cancer: present status and future perspectives. Lung cancer is the most common cause of death from malignancy. This is predominantly due to the poor prognosis of the mostly advanced tumor stages at the time of presentation. Prognosis of early, usually asymptomatic stages is more favourable, particularly in non-small-cell histologic types. Therefore, early detection using diagnostic tests promises reduction of mortality from lung cancer. Due to its high sensitivity for small pulmonary nodules - the most common manifestation of early lung cancer - computed tomography appears suitable as a screening test particularly as the high radiation exposure associated with standard examination protocols can be significantly reduced for this purpose. Due to the high prevalence of benign small pulmonary nodules diagnostic algorithms are required for non-invasive classification of detected nodules. Preliminary studies of low-dose CT using algorithms based on size and density of detected nodules revealed a high proportion of asymptomatic lung cancers and early resectable tumor stages with a small number of invasive procedures for benign nodules. Prior to a wide application of this technique in clinical routine more data is required as to appropriate inclusion criteria, screening intervals and most importantly the effect of screening on reduction of mortality from lung cancer.

Adult↗

PubMed2000

Screening for asymptomatic early bronchogenic carcinoma with low dose CT of the chest.

BACKGROUND: Survival of patients with lung carcinoma is very poor, particularly for patients with advanced disease. There are no early clinical symptoms, and screening with chest radiography has not been recommended. Computed tomography (CT) is superior to radiography for detection of pulmonary nodules but usually is associated with relatively high radiation exposure. Recently, accuracy of low dose CT has been shown to be similar to conventional dose CT. The goal of the current study was to assess the findings of low dose CT of the chest in heavy smokers. METHODS: More than 700 heavy smokers (> 20 pack years; age: > 40 years) underwent unenhanced low dose CT of the chest. Detected nodules were classified according to their density (soft tissue, calcified, fat) and size (< 6 mm, 6-10 mm, > 10 mm). In nodules larger than 10 mm with no CT features to suggest a benign lesion, histology was obtained. RESULTS: In approximately 40% of smokers, nodules smaller than or equal to 10 mm were detected. None was resected. In less than 3% of individuals, lesions larger than 10 mm were detected; 8 were bronchogenic carcinoma. All eight carcinomas were resectable. Lesions for which no histology was obtained were followed with low dose CT. CONCLUSIONS: Low dose CT detected 8 bronchogenic carcinomas in more than 700 heavy smokers. All eight were resectable. Pulmonary nodules measuring up to 10 mm were found in 40% of smokers. The significance of these small lesions has remained unclear.

Adult↗