“Density Mask”: An Objective Method to Quantitate Emphysema Using Computed Tomography

Evaluation of patients with pulmonary nodules: when is it lung cancer?: ACCP evidence-based clinical practice guidelines (2nd edition).

https://www.researchgate.net/profile/Anne_Dy_Buncio/publication/20858141_Quantitation_of_emphysema_by_computed_tomography_using_a_density_mask_program_and_correlation_with_pulmonary_function_tests/links/0fcfd511a8442e5cbd000000.pdf

Quantitation of emphysema by computed tomography using a "density mask" program and correlation with pulmonary function tests.

Nearly one-third of solitary pulmonary nodules are radiographically indeterminate for the presence of malignancy. Methods: FDG-PET imaging was used to differentiate benign and malignant solitary pulmonary nodules in 61 patients with radiographically indeterminate nodules. After confirmation of the histological diagnosis, the probability for cancer was established for positive and negative PET scans and compared to the risk estimates calculated using other patient variables. Results: FDG-PET had a sensitivity, specificity and positive predictive value of 93%, 88% and 92%, respectively, for detecting malignancy in indeterminate solitary pulmonary nodules. The probability of malignancy with a positive PET scan is 83%, which increases with the patient9s age (90% in >60 yr) and the size of the nodule. A negative PET scan is associated with only a 4.7% risk of malignancy. FDG-PET also accurately characterized hilar/mediastinal lymphadenopathy in 12 patients with associated lymph node lesions. Conclusion: FDG-PET imaging can be a useful noninvasive test to determine the risk estimate or probability of cancer as well as preoperative staging in patients with radiographically indeterminate solitary pulmonary nodules.

https://jnm.snmjournals.org/content/jnumed/37/6/943.full.pdf

Probability of Malignancy in Solitary Pulmonary Nodules Using Fluorine-18-FDG and PET

Purpose: To determine the dependence of absolute computed tomographic (CT) attenuation values on multi–detector row CT scanner type, convolution kernel, and tube current by using an anthropomorphic phantom. Materials and Methods: A customized phantom was designed with tissue-equivalent materials to simulate contrast material–enhanced liver, spleen, pancreas, aorta, kidney, 0- and 50-HU cylindric renal cysts, muscle, and fat. The phantom was scanned with five multi–detector row CT scanners (LightSpeed QXi, GE Healthcare, Milwaukee, Wis; MX8000, Philips Medical Systems, Best, the Netherlands; and Volume Zoom, Sensation 16 and Sensation 64, Siemens Medical Solutions, Forchheim, Germany) on five separate occasions with 120 kVp, low and high tube current settings, 3.00–3.75-mm section thickness, 50% overlap, and standard and high-spatial-resolution kernels. Standardized regions of interest (ROIs) were used to obtain 3510 attenuation measurements. Attenuation dependence on scanner, kernel, and tube current was ...

Multi-detector row CT attenuation measurements: assessment of intra- and interscanner variability with an anthropomorphic body CT phantom.

The CT density of the same pulmonary nodule can vary significantly between scanners or with the same scanner because several independent factors besides partial volume averaging can affect its determination. Hence a single CT number cannot be used to distinguish calcified from noncalcified nodules, ruling out direct extrapolation of quantitative data between scanners. The authors designed a phantom that simulates CT measurements in patients and permits comparison of CT density of each nodule with a physical standard derived from clinical experience. Tests on 35 patients using a GE 8800 showed that no malignant nodules and 65% of benign lesions were more dense than the phantom nodule. This method is independent of inter- and intra-scanner variation and facilitates standardized quantitative analysis of pulmonary nodules with current scanners.

E A Zerhouni

Papers

A standard phantom for quantitative CT analysis of pulmonary nodules.