Magnetic resonance imaging mri radiology mri scan lchsreunionfo
Thoracic computed tomography (CT) is considered the gold standard for detection lung pathology, yet its efficacy as a screening tool in regards to cost and radiation dose continues to evolve. Chest radiography (CXR) remains a useful and ubiquitous tool for detection and characterization of pulmonary pathology, but reduced sensitivity and specificity compared to CT. This prospective, blinded study compares the sensitivity of digital tomosynthesis (DTS), to that of CT and CXR for the identification and characterization of lung nodules. Ninety-five outpatients received a posteroanterior (PA) and lateral CXR, DTS, and chest CT at one care episode. The CXR and DTS studies were independently interpreted by three thoracic radiologists. The CT studies were used as the gold standard and read by a fourth thoracic radiologist. Nodules were characterized by presence, location, size, and composition. The agreement between observers and the effective radiation dose for each modality was objectively calculated. One hundred forty-five nodules of greatest diameter larger than 4 mm and 215 nodules less than 4 mm were identified by CT. DTS identified significantly more >4 mm nodules than CXR (DTS 32 % vs. CXR 17 %). CXR and DTS showed no significant difference in the ability to identify the smaller nodules or central nodules within 3 cm of the hilum. DTS outperformed CXR in identifying pleural nodules and those nodules located greater than 3 cm from the hilum. Average radiation dose for CXR, DTS, and CT were 0.10, 0.21, and 6.8 mSv, respectively. Thoracic digital tomosynthesis requires significantly less radiation dose than CT and nearly doubles the sensitivity of that of CXR for the identification of lung nodules greater than 4 mm. However, sensitivity and specificity for detection and characterization of lung nodules remains substantially less than CT. The apparent benefits over CXR, low cost, rapid acquisition, and minimal radiation dose of thoracic DTS suggest that it may be a useful procedure. Work-up of a newly diagnosed nodule will likely require CT, given its superior cross-sectional characterization. Further investigation of DTS as a diagnostic, screening, and surveillance tool is warranted.
Digital tomosynthesis in breast imaging. | Radiology
Digital Breast Tomosynthesis; ..
N2 - Two simulated sets of digital tomosynthesis images of the lungs, each acquired at a 90 degree angle from the other, with 19 projection images used for each set and SART iterative reconstructed, gives dual tomosynthesis slice image quality approaching that of spiral CT, and with a data acquisition time that is 3% of that of cone beam CT. This fast kV acquisition, should allow near real time tracking of lung tumors in patients receiving SBRT, based on a novel TumoTrakTM multi-source X-ray tube design. Until this TumoTrakTM prototype is completed over the next year, its projected performance was simulated from the DRR images created from a spiral CT data set from a lung cancer patient. The resulting dual digital tomosynthesis reconstructed images of the lung tumor were exceptional and approached that of the gold standard Feldkamp CT reconstruction of breath hold, diagnostic, spiral, multirow, CT data. The relative dose at 46 mAs was less than 10% of what it would have been if the digital tomosynthesis had been done at the 472 mAs of the CT data set. This is for a 0.77 fps imaging rate sufficient to resolve respiratory motion in many free breathing patients during SBRT. Such image guidance could decrease the magnitudes of targeting error margins by as much as 20 mm or more in the craniocaudal direction for lower lobe lesions while markedly reducing dose to normal lung, heart and other critical structures. These initial results suggest a wide range of topics for future work.
Image processing in the digital tomosynthesis for pulmonary imaging
Digital chest tomosynthesis (DTC) may provide a solution, according to two scientific session presentations made at the RSNA this week. Radiologists from Italy and the United States both agreed that a DTC exam could become a feasible alternative for a portion of at-risk individuals needing lung cancer screening.