ABSTRACT
OBJECTIVES: Evaluate the improvement in detecting lung nodules when using multidetector CT (MDCT) computer-assisted diagnosis (CAD). MATERIAL AND METHODS: Three radiologists (R1, R2, R3) with different levels of experience independently interpreted 30 MDCT examinations of the thorax taken for screening purposes, first without and then with CAD. The diagnosis was established by two of the three radiologists interpreting the images together, assisted by the CAD. RESULTS: The consensus reading identified 133 nodules, 61 (46%) of which were 4 mm or larger. The sensitivity values in the detection of nodules before and after using the CAD were 54% and 80% (R1), 38% and 71% (R2), and 70% and 88% (R3), respectively. When considering only the nodules that were 4 mm or larger, the sensitivity values varied before and after using the CAD, from 62% to 95% (R1), from 41% to 84% (R2), and from 74% to 92% (R3). By combining two by two the three radiologists' results obtained without the CAD, the sensitivity values were 65%, 83%, and 77%, respectively, for all the nodules, and 70%, 85%, and 77% for the nodules that were 4 mm or larger. The CAD induced a total of 105 false-positive results, with a mean of 3.5 per examination. CONCLUSION: The lung nodules missed by the radiologist can be detected if the CAD is used as a second reader. The CAD can be at least as beneficial as the use of a second independent reader.
Subject(s)
Diagnosis, Computer-Assisted , Image Processing, Computer-Assisted/methods , Lung Neoplasms/diagnostic imaging , Radiology/standards , Tomography, X-Ray Computed/methods , Adult , Aged , False Positive Reactions , Feasibility Studies , Female , Humans , Male , Mass Screening , Middle Aged , Observer Variation , Pilot Projects , Prospective Studies , Radiography, Thoracic , Sensitivity and Specificity , Smoking , Solitary Pulmonary Nodule/diagnostic imaging , Tomography, Spiral ComputedABSTRACT
The increasing demand for real-time applications requires the use of variable-rate quantizers having good performance in the low bit rate domain. In order to minimize the complexity of quantization, as well as maintaining a reasonably high PSNR ratio, we propose to use an entropy-coded lattice vector quantizer (ECLVQ). These quantizers have proven to outperform the well-known EZW algorithm's performance in terms of rate-distortion tradeoff. In this paper, we focus our attention on the modeling of the mean squared error (MSE) distortion and the prefix code rate for ECLVQ. First, we generalize the distortion model of Jeong and Gibson (1993) on fixed-rate cubic quantizers to lattices under a high rate assumption. Second, we derive new rate models for ECLVQ, efficient at low bit rates without any high rate assumptions. Simulation results prove the precision of our models.
Subject(s)
Advertising , Bibliographies as Topic , Consumer Product Safety , Adolescent , Child , Curriculum , Health Education , Humans , United StatesABSTRACT
The authors report a case of leiomyomatosis peritonealis disseminata in a non pregnant woman. The numerous nodules were first considered by the surgeon as a disseminated abdominal carcinoma, fact which often happens in the literature. Diagnosis was changed on frozen section showing histologically benign appearing smooth muscle cells, consistent with leiomyomatosis peritonealis disseminata this diagnosis was confirmed by examination of. Paraffin sections. Though electron microscopic studies favor the smooth-muscle nature of the cells, the proper origin of this disease is still unknown : the role of oestrogens and metaplasia of the subcoelomic mesenchyme are discussed.
