Biomedical subjects

Daniel T Boll

Publications and source records attributed to Daniel T Boll.

21 records · Page 2Linked to original sources

PubMedDate not supplied

Helical computed tomography of the pancreas: potential impact of higher concentrated contrast agents and multidetector technology.

The introduction of multidetector helical computed tomography (CT) has revolutionized the field of pancreatic imaging and has created a new dimension of temporal and spatial resolution. The speed of multidetector CT can either be used to reduce the time needed to cover a given volume or to increase the resolution along the z-axis, thereby resulting in nearly isotropic voxels. Pancreatic perfusion phases can thus be more clearly differentiated and small structures are better delineated, leading to an improvement in the diagnostic value of pancreatic CT. Contrast media with a higher iodine concentration seem to be superior to lower concentrated contrast agents, mainly because of the better evaluability of the vessels in the arterial examination phase. This manuscript reports current CT imaging strategies for patients with pancreatic cancer with emphasis on vascular invasion, lymph node metastasis, liver metastasis, and peritoneal carcinomatosis.

Contrast Media↗

PubMedDate not supplied

Assessment of automatic vessel tracking techniques in preoperative planning of transluminal aortic stent graft implantation.

OBJECTIVE: To evaluate automatic vessel tracking techniques in the course of preoperative planning prior to transluminal aortic endograft implantation by comparing accuracy, reproducibility, and postprocessing time with source image and volume-rendered analysis methods. METHODS: Multislice computed tomography datasets of 5 patients with abdominal aortic aneurysms were preoperatively examined, performing volumetric analysis of diameter and position of renal artery orifices, aneurysmal neck, maximal aneurysmal extension, aortic bifurcation, and iliac arteries and bifurcation. Analysis was realized by utilizing transverse datasets, volume rendering, and automated vessel tracking strategies (MxView, Philips, Best, The Netherlands). Measurement techniques were evaluated by 2 independent readers 3 times for each patient and measurement modality. Statistical analysis evaluated accuracy of the measurements and intra- and interobserver reliability. Postprocessing time was documented. RESULTS: Using transverse source datasets, intraobserver reliability ranged from 0.49 to 0.58. Intraobserver reliability improved to 0.7 to 0.98 when volume-rendered datasets were evaluated. Interobserver variability for transverse and volume-rendered datasets ranged from 0.49 to 0.76 and 0.70 to 0.96, respectively. Automated vessel tracking datasets did not demonstrate any intra- or interobserver variability. Based on transverse datasets, the length and diameter of iliac arteries and location and diameter of the aneurysmal neck were measured as statistically different in all cases in contrast to volume rendering and automated segmentation techniques. Postprocessing time consumption for measurements based on transverse, volume-rendered, and automated tracking segmentation datasets averaged 3.32 minutes, 25.43 minutes, and 2.24 minutes, respectively. CONCLUSIONS: Preoperative measurements improve significantly if datasets are evaluated based on volume-rendering techniques. This time-consuming procedure can be shortened, while further reducing observer variability, with automatic segmentation techniques.

Aged↗

PubMedDate not supplied

Spectral coronary multidetector computed tomography angiography: dual benefit by facilitating plaque characterization and enhancing lumen depiction.

OBJECTIVE: To assess ex vivo specimens of atherosclerotic coronary arteries by dual energy (DE) multidetector computed tomography (MDCT) imaging, and to correlate depicted vessel lumen morphology and detected tissue characteristics with histopathologic analysis. METHODS: Coronary arteries were imaged on a 16-slice MDCT using a DE protocol consisting of a 90- and 140-kV scan. Coronary arteries were perfused with iodine- and gadolinium-based contrast agents. The DE K-edge subtractions were performed. Regions-of-interest were placed on histopathologically/radiographically-matched vascular lumen and wall, fibromuscular and calcified plaque, and fat tissues. Vascular/tissue contrast-to-noise ratios (CNR) were calculated, and their dependence on tissue type and contrast agent type was statistically evaluated. RESULTS: Tissue CNR analysis confirmed that all tissue types were successfully distinguished. Vascular wall and fibromuscular plaque achieved a significant increase in CNR ratios when DE techniques were used compared with 140 kV protocols. CONCLUSIONS: Spectral DE MDCT imaging of ex vivo atherosclerotic coronary arteries allows successful tissue characterization and enhances depiction of coronary lumen.

Angiography, Digital Subtraction↗