(Radiology Review) Multidetector-row computed tomography (MDCT) enables precise volumetric assessment of small pulmonary nodules by identifying the underlying cardiac phase, according to U.S. radiologists.
In the November issue of the American Journal of Roentgenology, Dr Daniel T. Boll and colleagues at University Hospitals of Cleveland note that "cardiovascular motion was disproportionately conveyed to various pulmonary segments and led to changes in the volume of pulmonary nodules, especially in small pulmonary nodules." Assessing nodule growth rate is an important consideration for differentiating benign and malignant nodules, and requires accurate measurement of nodule volume, they wrote.
To investigate further, the researchers employed 16-row MDCT to image 73 small noncalcified pulmonary nodules in 30 patients. Computer-aided automatic segmentation algorithms were used to assess the volume of each nodule throughout the cardiac cycle. The measurements were calculated three times to improve accuracy.
"To ensure the validity of the subtle changes in volume that were detected, we determined the volume and signal attenuation in phantom data sets and patient nodules without temporal or spatial differentiation," they wrote. Volume changes were correlated to "cardiac phases, nodular location, and mean nodular size."
According to the authors, a general tendency toward overestimating nodular volume was demonstrated. True deformation and compression of small pulmonary nodules was demonstrated, and resulted in a statistically significant volume variation. "Differentiating pulmonary nodules in cardiac phases, pulmonary locations, and mean nodular volumes, we found that one single effect did not determine the amount of cardiovascular motion conveyed to pulmonary parenchyma and subsequently led to nodule deformation," they wrote.
Advances in imaging technology that enhance temporal and spatial resolution will rely on parameters such as cardiac phase, to correlate anatomical and physiological information, they stated. The study results supported the use of ECG-gated MDCT units "to allow visualization of pulmonary nodules in specific cardiac phases for reliable assessment of volume," they concluded.
"Volumetric Assessment of Pulmonary Nodules with ECG-Gated MDCT"
Daniel T. Boll et al
Department of Radiology, University Hospitals of Cleveland
Case Western Reserve University
11100 Euclid Ave, Cleveland, OH 44106-5056 USA
Am J Roentgen 2004 (November); 183:1217-1223
By Radiology Review
November 24, 2004
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