IMAGING NEWS
low dose cT-guided lung biopsy protocol maintains quality, minimizes exposure
New guidelines for CT-guided biop-
sies of lung nodules significantly reduce radiation exposure. According to research presented at the recent meeting of the Society of Interventional Radiology, this allows individuals to benefit from the pro- cedure, which may cut down on overall lung cancer deaths. “The published early results of a trial using computed tomogra- phy to detect lung nodules demonstrated that screening with low-dose CT reduced mortality from lung cancer by 20 percent compared to screening with chest X-rays alone,” said Jeremy Collins, M.D., professor of radiology at Northwestern University
in Chicago, Ill. “Statistically, many people who undergo screening will have nodules detected with CT and a biopsy may be rec- ommended. We want to minimize the side effects of the biopsy procedure,” he added. For this study, researchers implemented the new CT imaging protocol for lung- nodule biopsy and then reviewed data from 100 people, half of whom underwent CT-guided biopsies before the new proto- col was used and half after the protocol went into effect. The low dose protocol led to a dramatic 66 percent drop in radiation dose, and image quality was maintained for all of the CT-guided biopsies. The con- clusion is that the new protocol can be adopted immediately to reduce exposure, but interventional radiologists will still need to evaluate each person on a case- by-case basis, especially smaller people or those who have anatomy that is more dif- ficult to image. The dose can be reduced even further for children, but more studies need to be done to tailor the protocol.
http://tinyurl.com/Low-dose-lung-biopsy
vcaM-1 targetted Mri contrast agent enables early detection of brain metastases
Metastasis to the brain is a leading cause
of cancer mortality. The current diagnos- tic method of gadolinium-enhanced MRI is sensitive only to larger tumors, when therapeutic options are limited. Earlier detection of brain metastases is thus criti- cal for improved treatment. A targeted MRI contrast agent based on micropar- ticles of iron oxide has been developed by a research group from the CR-UK/MRC Gray Institute for Radiation Oncology and Biology at the University of Oxford, UK.
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The new contrast agent enables imaging of endothelial vascular cell adhesion mol- ecule-1 (VCAM-1). Research was carried out to determine whether VCAM-1 is up- regulated on vessels associated with brain metastases, and if so, whether VCAM-1– targeted MRI enabled early detection of these tumors. It was found that cerebro- vascular VCAM-1 expression was indeed evident on tumor-associated vessels in two separate murine models of brain metasta- sis. VCAM-1 expression detected by MRI increased significantly (P < 0.0001) with tumor progression, and tumors showed no gadolinium enhancement.
Impor-
tantly, expression of VCAM-1 was shown in human brain tissue containing both established metastases and micrometas- tases. Translation of this approach to the clinic could increase therapeutic options and change clinical management in a sub- stantial number of cancer patients.
http://tinyurl.com/Molecular-MRI
DI EUROPE
virtual colonos- copy now shown to be oK for over 65s
The 2008 US ACRIN National CT
colonography trial showed that virtual colonoscopy was comparable to standard colonoscopy in its ability — in patients over 50 years of age but younger than 65 — to accurately detect cancer and pre- cancerous polyps and could thus serve as a primary colorectal cancer screening option for patients in this age range. A paper just published in Radiology now reports that the results for virtual colonos- copy in over-65s were identical to those already found in the 50-65 age group. As Dr D Johnson of the Mayo Clinic, and lead author of the paper said “CT colo- nography is a perfectly viable colorectal cancer screening tool for the traditional pensioned or retired age population and may attract more seniors to be screened for colorectal cancer — which is so suc- cessfully treated when detected early”. In the ACRIN trial, 90 percent of the pol- yps 1 centimeter or larger — the polyps most likely to become cancerous — were detected by CT colonography. Polyps as small as one-half centimeter were also detected by CT colonography with a high degree of accuracy. In the recent trial, it was found that the percentage of partici- pants with large polyps was significantly greater among the over 65 group than in the under 65 group (6.9% vs 3.5% respec- tively); however, even if intermediate-sized polyps of 6mm or larger were targeted for removal with standard colonoscopy, the colonoscopy referral rate would not exceed 12.6 percent. Colorectal cancer is the third most frequently diagnosed cancer and second leading cause of cancer death in men and women in the Western world
http://radiology.rsna.org/
APRIL/MAY 2012
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