1,721,108 research outputs found
Low-dose CT angiography: which contrast medium? Reply.
No full textAims: This prospective pilot study investigated the feasibility of perfusion computed tomography parameters as surrogate markers of angiogenesis and early response following sorafenib administration in patients with advanced hepatocellular carcinoma. Methods: Ten patients were evaluated with perfusion computed tomography before starting sorafenib and after 3 months. Blood flow, blood volume, mean transit time, hepatic arterial fraction, and permeability surface-product were compared in tumour lesions and in hepatic parenchyma at baseline and at follow-up. Correlation between these parameters and changes in alpha-fetoprotein levels was calculated. Results: At baseline, blood volume, blood flow, hepatic arterial fraction and permeability surface values were higher in lesions compared to those in hepatic parenchyma, while mean transit time was lower (p < 0.05). After sorafenib treatment, only mean transit time was significantly increased versus baseline (p < 0.05). At follow-up, plasma alpha-fetoprotein levels decreased in all patients. At follow-up, an inverse correlation was observed between baseline mean transit time and changes in alpha-fetoprotein (r = -0.6685, p = 0.0125), as well as a correlation between baseline blood flow and alpha-fetoprotein (r = 0.6476, p = 0.0167). Conclusion: This pilot study suggests that after sorafenib treatment an increase in mean transit time observed in tumour lesions is inversely correlated with alpha-fetoprotein reductions after therapy. Mean transit time may represent a possible marker of response irrespectively of alpha-fetoprotein values
CT Perfusion of Head and Neck Tumors: How We Do It
No full textOBJECTIVE:
Our purpose is to illustrate the pathophysiologic, physical, and technical principles of MDCT perfusion imaging of head and neck tumors. The rationale for data acquisition and the interpretation of perfusion parameters will be discussed in the context of results recently published in the literature.
CONCLUSION:
MDCT perfusion imaging of primary and recurrent head and neck tumors is feasible and can yield functional information that is useful for tumor grading and assessment of treatment response
CT Colonography Atlas: For the Practicing Radiologist (Medical Radiology / Diagnostic Imaging)
No full textTable of Contents
Normal colon.
Anatomical variants: positional anomalies of colon.
Pitfalls in imaging.
Diverticular disease.
Lipomatous lesions of the colon.
Inflammatory bowel disease.
Polyps: pedunculated.
Sessile polyps.
Flat lesion.
Colon cancer.
Rectal cancer.
The ileocecal valve.
Operated large bowel
Iodine Concentration and Optimization in Computed Tomography Angiography
No full textComputed tomography (CT) technology has seen a dramatic evolution in the recent past that has deeply changed the face of this diagnostic modality. Since the early days of helical single-slice and then multislice CT, CT angiography (CTA) has been one of the most technically demanding applications, both in terms of scanning technique and contrast medium (CM) injection protocol, due to the need to acquire a large amount of high-resolution data over a limited period corresponding to the peak contrast enhancement of the arterial system. Iodine concentration is one of the main determinants of arterial enhancement in CTA, and current low-osmolar and iso-osmolar nonionic CM for intravascular administration still come in a handful of molecules, but a relatively wide range of different iodine concentrations. This gives the opportunity to optimize CTA protocols as a function of several factors such as patient characteristics, CT technology, and CM features in an attempt to maximize the diagnostic yield of CTA examinations while considering patient safety and avoiding unnecessary extra costs. Our aim is to provide an up-To-date overview of the existing evidence on how changing iodine concentration can have an impact on CTA performance, especially with the use of state-of-The-Art CT and power injector technology, in the perspective of improving patient carewhileminimizing overall exposure to iodinated CM and ionizing radiation
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