A proposed acute craniocervical trauma scoring system could be used as a guide to select blunt trauma patients for multidetector CT angiographic evaluation. In a retrospective study of 830 consecutive patients who presented to an emergency department with acute blunt head and neck trauma over 9 years, Delgado Almandoz and colleagues discovered that multidetector CT angiography depicted injury in 12.8% of those patients. A proposed scoring system based on independent predictors of arterial injury—cervical subluxations/dislocations, fracture lines reaching an arterial structure, and high-impact mechanisms of injury—could aid in identifying patients at highest risk of arterial injury and in selecting blunt trauma patients for multidetector CT angiographic evaluation to assess for arterial injury, the authors concluded.

Patients with mild Alzheimer disease (AD) demonstrate impaired neuronal function along the dorsal visual pathway. Using functional MR imaging, Bokde and colleagues measured brain activation in 12 patients with mild AD and 14 age-matched healthy control subjects as they performed face-matching and location-matching tasks. In the control group, the researchers found that the visual perception tasks selectively activated the visual pathways, while there was no selective activation in the patients with AD. Along the dorsal visual pathway, the brains of patients with AD recruited additional regions for the location-matching tasks, primarily in the parietal and frontal lobes. The researchers propose that the increased activation in the patients with AD may represent a compensatory mechanism for decreased effectiveness in frontal visual processing and that neuronal function along the dorsal visual pathway is affected by AD earlier than that of the ventral visual pathway.

The extent of delayed gadolinium enhancement, as assessed with cardiac MR imaging, may significantly diminish during the 1st week after myocardial infarction and successful reperfusion therapy; hence, to properly estimate the infarct size, contrast-enhanced cardiac MR imaging should be performed about 7 days after reperfusion therapy. Ibrahim and colleagues studied 17 patients with reperfused acute myocardial infarction who underwent cine and contrast-enhanced MR imaging 1, 7, 35, and 180 days after reperfusion. The researchers found that the infarct size significantly decreased between days 1 and 7, particularly within the epicardial region. The results demonstrate that timing of contrast-enhanced cardiac MR imaging is crucial for accurate measurement of myocardial infarct size.

MR imaging may not be an acceptable screening tool for some women at elevated risk for breast cancer. In a study of a group of women who had completed 0-, 12-, and 24-month screenings with mammography plus US as part of the American College of Radiology Imaging Network 6666 US Screening Protocol at 21 institutions, Berg and colleagues found that of 1215 women with elevated breast cancer risk who could, according to protocol guidelines, undergo breast MR imaging, only 58% (95% CI: 55%, 61%) agreed to participate. Claustrophobia was the most common reason given for nonparticipation, followed by time constraints and financial concerns. The results suggest that there may be a large group of women at elevated risk for breast cancer for whom MR imaging would not be acceptable, and alternative screening strategies should be considered.

Early increases in apparent diffusion coefficients (ADCs) in rectal carcinoma obtained 1 week after the start of chemotherapy and radiation therapy (CRT) correlate with tumor histopathologic downstaging after preoperative CRT. In a prospective study of 37 patients with primary rectal carcinoma undergoing preoperative CRT, Sun and colleagues performed diffusion-weighted MR imaging in all patients before therapy, at the end of the 1st and 2nd week of therapy, and before surgery. During the long-course CRT, earlier increases in ADC were seen in the tumor-downstaged group than in the nondownstaged group. Early temporal changes in ADCs and pretherapy ADCs measured at diffusion-weighted MR imaging can depict patients with locally advanced rectal carcinomas that are resistant to preoperative CRT, allowing for prompt modification in treatment protocols, the authors concluded.

Among commercially available software packages provided by various CT manufacturers, CT perfusion imaging maps have proven to be significantly different, presumably because of differences in tracer-delay sensitivity. In a study examining CT perfusion data from 10 stroke patients that were postprocessed by using five commercial software packages—each of which had a different algorithm—Kudo and colleagues discovered significant differences in the abnormal areas and quantitative values of cerebral blood flow and mean transit time, while values for cerebral blood volume were almost identical among the software packages. The authors concluded that overestimation of abnormalities in cerebral blood flow and mean transit time occurred in software utilizing delay-sensitive algorithms and that these variations should be minimized to improve the reliability of software analysis.

Adrenal adenomas can be differentiated from nonadenomas at 3T MR imaging with either a 2D or 3D single-breath-hold, dual gradient-echo (GRE) technique. In a retrospective study of 34 patients with 37 adrenal lesions, Marin and colleagues compared the signal intensity index and adrenal-to-spleen, adrenal-to-liver, and adrenal-to-muscle signal intensity ratios for each lesion between the 2D and 3D techniques using repeated-measures analysis of variance. By sampling the first opposed-phase echo followed by the first in-phase echo during the same breath hold, the 3D dual GRE technique can minimize the effects of T2* decay when compared with a standard 2D dual GRE technique, without a penalty in the signal-to-noise ratio obtained at 3T MR imaging, the authors concluded.

Aortic arch stiffness on MR images may help identify patients at risk for hypertensive cardiovascular disease. In a study of 50 patients undergoing treatment for hypertension, Brandts and colleagues found that aortic arch pulse wave velocity was significantly associated with left ventricular mass and lacunar brain infarcts, independent of age, sex, and hypertension duration. MR could be useful in identifying high-risk hypertensive patients who could benefit from more aggressive therapy, the researchers concluded.

Photon-counting spectral CT could substantially improve characterization of focal cystic high-attenuation lesions in a renal phantom. Boll and colleagues developed a renal phantom containing cystic lesions grouped in nonenhancing cyst and hemorrhage series and an iodine-enhancing series. Spectral CT is based on new detector designs that may possess energy-sensitive photon-counting abilities, thereby facilitating the assessment of quantitative information about the elemental and molecular composition of tissue or contrast materials. Spectral CT has the potential to distinctly characterize hyperattenuating fluids by identifying proeteinaceous and hemorrhagic lesions through assessment of their distinct levels of attenuation and by demonstrating iodine-containing lesions through analysis of their specific k-edge discontinuities, the authors concluded.

In some patients, adjusting iodine dose proportionally to total body weight may overestimate the amount of contrast medium needed for aortic and liver CT. In a study of 120 patients, Kondo and colleagues found that lean body weight, instead of total body weight or estimated blood volume, allowed more precise dose calculations. To achieve consistent hepatic enhancement, the iodine dose required may be estimated more precisely and with reduced patient-to-patient variability when lean body weight is used, the researchers concluded.