Pulmonary nodules: experimental and clinical studies at low-dose CT.

PURPOSE To compare the number of pulmonary nodules detected at helical low- and standard-dose computed tomography (CT) and to investigate the diagnostic value of low-dose CT with a radiation exposure equivalent to that used at chest radiography. MATERIALS AND METHODS Two radiologists recorded pulmonary nodules at standard-dose (250 or 100 mA, pitch of 1; 200 mA, pitch of 2) or low-dose CT (50 or 25 mA, pitch of 1 or 2) in five postmortem specimens and 75 patients. Nodules were assessed by size (5 mm or smaller, 6-10 mm, or larger than 10 mm) and by diagnostic confidence ("definite nodule," "definite lesion, not classic nodule," or "questionable lesion, possibly representing a vessel") with the Wilcoxon signed rank test. Artifacts depicted at low-dose CT were recorded. RESULTS There were no statistically significant differences in the number of nodules detected at standard- or low-dose CT except in nodules 5 mm or smaller that were assessed as definite nodules at standard- or low-dose CT (25 mA, pitch of 2) (472 vs 397, P < .05). Artifacts that possibly interfered with nodule detection were observed exclusively at CT with 25 mA and a pitch of 2. CONCLUSION Pulmonary nodules were detected reliably at CT with 50 mA and pitch of 2 or with 25 mA and a pitch of 1. However, further reduction of the dose to that used at chest radiography was associated with a significant decrease in the number of nodules 5 mm or smaller that were detected, possibly due to artifacts.

[1]  D. McCauley,et al.  Low-dose CT of the lungs: preliminary observations. , 1990, Radiology.

[2]  J. J. Broerse,et al.  Comparison of two methods for assessing patient dose from computed tomography. , 1994, The British journal of radiology.

[3]  N. Müller,et al.  Low-dose high-resolution CT of lung parenchyma. , 1991, Radiology.

[4]  C J Bergin,et al.  Spiral CT of the lungs: optimal technique and resolution compared with conventional CT. , 1994, AJR. American journal of roentgenology.

[5]  Feng Li,et al.  Mass screening for lung cancer with mobile spiral computed tomography scanner , 1998, The Lancet.

[6]  A. Wright,et al.  Comparison of spiral-acquisition computed tomography and conventional computed tomography in the assessment of pulmonary metastatic disease. , 1994, The British journal of radiology.

[7]  D Blume,et al.  Pulmonary nodule: evaluation with spiral volumetric CT. , 1991, Radiology.

[8]  A. Dwyer,et al.  Matchmaking and McNemar in the comparison of diagnostic modalities. , 1991, Radiology.

[9]  J. Wade,et al.  CT standard protocols are of limited value in assessing actual patient dose. , 1997, The British journal of radiology.

[10]  J. Poletti.  Patient doses from CT in New Zealand and a simple method for estimating effective dose. , 1996, The British journal of radiology.

[11]  B. Wall,et al.  The Increasing Importance of X Ray Computed Tomography as a Source of Medical Exposure , 1995 .

[12]  [Postmortem high-resolution computed tomography of the lung. Radiologic-morphologic correlations]. , 1993, Der Radiologe.

[13]  C. Claussen,et al.  Pulmonary nodules in spiral volumetric and single slice computed tomography. , 1994, European journal of radiology.

[14]  T. Westermeier,et al.  Pulmonary nodules: detection with low-dose vs conventional-dose spiral CT , 1998, European Radiology.

[15]  D. Nosske,et al.  Effective doses to members of the public from the diagnostic application of ionizing radiation in Germany , 1997, European Radiology.

[16]  S. Coley,et al.  Pulmonary arteriovenous malformations. , 1998, Clinical radiology.

[17]  K S Lee,et al.  CT of the chest: minimal tube current required for good image quality with the least radiation dose. , 1995, AJR. American journal of roentgenology.

[18]  J E Aldrich,et al.  Chronic infiltrative lung disease: comparison of diagnostic accuracies of radiography and low- and conventional-dose thin-section CT. , 1994, Radiology.

[19]  J. J. Broerse,et al.  Survey of CT techniques and absorbed dose in various Dutch hospitals. , 1997, The British journal of radiology.

[20]  K S Pentlow,et al.  Radiation dose in CT. , 1992, Radiographics : a review publication of the Radiological Society of North America, Inc.

[21]  A. Leung,et al.  Simulated dose reduction in conventional chest CT: validation study. , 1997, Radiology.

[22]  J. Remy,et al.  Pulmonary nodules: detection with thick-section spiral CT versus conventional CT. , 1993, Radiology.

[23]  B. Wall,et al.  Revised radiation doses for typical X-ray examinations. Report on a recent review of doses to patients from medical X-ray examinations in the UK by NRPB. National Radiological Protection Board. , 1997, The British journal of radiology.

[24]  S. D. Davis,et al.  CT evaluation for pulmonary metastases in patients with extrathoracic malignancy. , 1991, Radiology.

[25]  H. Ohmatsu,et al.  Peripheral lung cancer: screening and detection with low-dose spiral CT versus radiography. , 1996, Radiology.

[26]  K. Nishizawa,et al.  Determinations of organ doses and effective dose equivalents from computed tomographic examination. , 1991, The British journal of radiology.