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Headlines
Leading the News
Research
Technology
Medical-Legal Issues
Clinical Practice
Leading the News
Rules Aim to Avoid Excess CT in Children with Head Injuries
Computed tomography (CT) scanning of children with head injuries carries a risk of radiation-induced malignancy. A team of researchers conducted a study to identify children at very low risk of clinically important traumatic brain injuries for whom the imaging procedure might not be necessary. The study involved the analysis of more than 42,000 children with head injuries, and CT scans were performed in almost 15,000 patients. Serious brain injuries were diagnosed in 376 children, and 60 patients underwent neurosurgery. Of this group, the researchers discovered that about 20 percent of children over age two years were at low risk of sustaining a serious brain injury, thus making the head CT they received unnecessary. Nearly 25 percent of children younger than two had a head CT that was not needed. The researchers developed guidelines for identifying minor injuries that require no CT scans, including when there is no scalp swelling, palpable skull fracture, or significant loss of consciousness in children under two. Children older than two who are at low risk can be identified as having normal mental status, no unconsciousness, no vomiting, no indications of fracture at the base of the skull, and no severe headache. These criteria were applied to data from a second group of more than 8,000 children, and the researchers learned that they were nearly 100 percent accurate at predicting low-risk injuries.
From "Identification of Children at Very Low Risk of Clinically-Important Brain Injuries After Head Trauma: A Prospective Cohort Study"
Lancet (09/15/09) Kuppermann, Nathan; Holmes, James F.; Dayan, Peter S.; et al.
Research
DTI Identifies Different Types of Parkinsonian Disorders
Patients with progressive supranuclear palsy (PSP) have been found to have an increased apparent diffusion coefficient average (ADCave) in several brain areas, according to a study that used diffusion tensor imaging (DTI) to image the brains of nine patients with probable PSP as well as 11 patients with probable corticobasal degeneration (CBD) and seven controls. Areas of heightened ADCave in PSP patients included the thalamus, cingulum, motor area, and the supplementary motor area (SMA). Researchers also found that fractional anisotropy (FA) was decreased in these patients in the fronto-orbital white matter, the anterior cingulum, and the motor area. Additionally, patients with CBD were found to have an increased ADCave in the motor thalamus, the precentral and postcentral gyri, and the bilateral SMA, while FA was primarily decreased in the precentral gyrus and the SMA. Based on these findings, the researchers believe DTI to be useful in the differential diagnosis of these parkinsonian disorders.
From "Diffusion Tensor Imaging Shows Different Topographic Involvement of the Thalamus in Progressive Supranuclear Palsy and Corticobasal Degeneration"
American Journal of Neuroradiology (09/09) Vol. 30, No. 8, P. 1482; Erbetta, A.; Mandelli, M. L.; Savoiardo, M.; et al.
Researchers Conduct Review of Possible Imaging Modalities to Visualize Hepatic Fat
There is a range of conditions - including simple hepatic steatosis, steatohepatitis with inflammatory changes, and end-stage liver disease with fibrosis and cirrhosis - encompassed in fatty liver disease. Hepatic steatosis is frequently affiliated with diabetes and obesity, and it may be a secondary effect of alcohol and drug use, toxins, viral infections, and metabolic diseases. Early detection is vital to implement appropriate management and block progression. Although histopathologic analysis is the reference standard for detecting and measuring the concentration of fat in the liver, results are susceptible to sampling error, while morbidity and complications can ensue. Moreover, the technique cannot be repeated frequently enough to monitor treatment response, but imaging is repeatable and permits evaluation of the entire liver, therefore avoiding sampling error. Imaging methods' advantages and limitations must be understood while the imaging setting must be suitable in order to determine which methods will be appropriate. Ultrasonography can effectively detect moderate or severe fatty infiltration but is constrained by a lack of interobserver reliability and intraobserver reproducibility. Computed tomography permits quantitative and qualitative assessment and boasts generally high reliability and accuracy, the trade-off being that the results may be confused by hepatic parenchymal changes owing to cirrhosis or depositional diseases. Magnetic resonance (MR) imaging with appropriate sequences also is characterized by high sensitivity, and MR spectroscopy offers unique benefits for some applications. But both methods are costly and too complicated for the monitoring of steatosis. The review is published in the September 2009 issue of RadioGraphics.
From "Imaging-Based Quantification of Hepatic Fat: Methods and Clinical Applications"
RadioGraphics (09/09) Vol. 29, No. 5, P. 1253; Ma, Xiaozhou; Holalkere, Nagaraj-Setty; Kambadakone, Avinash; et al.
MRI Used to Show Increasing Mural Inflammation in Crohn Disease
Researchers conducted a study to confirm proposed magnetic resonance imaging (MRI) features of Crohn disease activity against a histopathologic reference. The research involved MRI scanning applied to 18 consecutive patients with Crohn disease undergoing elective small-bowel resection, and the Harvey-Bradshaw index, the C-reactive protein level, and disease chronicity were recorded. A positive correlation was drawn between acute inflammatory score (AIS) with mural thickness and mural/cerebrospinal fluid (CSF) signal intensity ratios on T2-weighted fat-saturated images, but not with mural enhancement at 30 and 70 seconds. Research demonstrated a higher AIS with layered mural enhancement, which is also commonly affiliated with coexisting fibrostenosis. The mural/CSF signal intensity ratio on T2-weighted fat-saturated images was higher in histologically edematous bowel than in nonedematous bowel, and no correlation between any lymph node characteristic and AIS was determined. Researchers concluded that histologic features of acute small-bowel inflammation in Crohn disease are reflected by increasing mural thickness, high mural signal intensity on T2-weighted fat-saturated images, and a layered pattern of enhancement. The study is published in the September 2009 issue of Radiology.
From "Mural Inflammation in Crohn Disease: Location-Matched Histologic Validation of MR Imaging Features"
Radiology (09/01/09) Vol. 252, No. 3, P. 712; Punwani, Shonit; Rodriguez-Justo, Manuel; Bainbridge, Alan; et al.
Technology
CAD Boosts Breast MRI Specificity
Researchers carried out a study to assess the effectiveness of 3.0-T breast magnetic resonance imaging (MRI) interpretation using manual and fully automated kinetic analyses. They determined that false-positive findings can be reduced through the use of computer-aided detection (CAD) technology. The researchers retrospectively analyzed data from 426 women who received contrast-enhanced breast MRI scans between May 2005 and December 2006, and all patients were studied using both a manual kinetic analysis and CAD. Sixty-five of those patients had 71 breast lesions that were detected surgically or by core biopsy, and the diagnostic accuracy of CAD was assessed on all 65 patients. Forty-nine of the lesions were determined to be malignant, 12 were benign, and five were high-risk lesions. The researchers found the mean specificity of breast MRI scanning with CAD to be higher than with manual kinetic analysis. They demonstrated that automated analysis at 50 percent and 100 percent thresholds exhibited a high sensitivity and specificity for readers with varying levels of experience. The results were reported in the September online edition of European Radiology.
From "Computer-Aided Detection (CAD) for Breast MRI: Evaluation of Efficacy at 3.0 T"
European Radiology (09/02/09) Meeuwis, Carla; van de Ven, Stephanie M.; Stapper, Gerard; et al.
Iodinated Contrast Agents Have Effect on ADC in Diffusion Weighted MRI
A group of researchers assessed the impact of iodine contrast agent on diffusion signal intensity and apparent diffusion coefficient (ADC) in diffusion-weighted imaging (DWI) studies in magnetic resonance imaging (MRI) examination shortly after computed tomography (CT) contrast imaging. They reported that ADC was calculated from the signal intensity of DWI using phantoms filled with contrast agent on a 1.5 T MRI scanner. The signal intensities of DWI and ADC in 10 patients examined by MRI study were evaluated less than 40 minutes after injection of 100 mL of iopamidol for CT study. The researchers saw an increase until a CT value of 190 HU, but no changes above this value were demonstrated. The CT value increases were accompanied by a decline in ADC. The researchers observed that the signal intensity of DWI was significantly increased and ADC was significantly decreased less than 40 minutes after injection of iopamidol. They concluded that the rate of ADC decrease must be recognized because it is reliant on the density of iodine contrast agents.
From "Effects of Iodinated Contrast Agent on Diffusion Weighted Magnetic Resonance Imaging"
Academic Radiology (10/09) Vol. 16, No. 10, P. 1196; Ogura, Akio; Hayakawa, Katsumi; Miyati, Tosiaki; et al.
Medical-Legal Issues
Senate Bill Calls for 65 Percent Equipment Utilization Rate
The U.S. Senate Finance Committee has released a $856 billion health care reform bill that would set a 65 percent equipment utilization rate for Medicare reimbursement of imaging studies, which is 25 percent lower than the level proposed in original drafts of the legislation. "We're very pleased with this rate," says Josh Cooper with the American College of Radiology. "[The shift] is a direct result of negotiations conducted with the Senate Finance Committee by the American College of Radiology and our partner, the Access to Medical Imaging Coalition." If the bill is approved, the 65 percent utilization rate will be maintained for the first four years of the legislation's decade-long tenure, during which time an impact study will be performed to determine if the rate is cost-effective, according to Cooper. The Secretary of Health and Human Services is authorized to raise the rate an additional 10 percent if the study deems it not to be cost-effective. The Senate bill also includes a physician self-referral provision requiring any doctor who owns imaging equipment to report this fact to his or her patients and supply a list of alternative facilities that provide the service. In addition, the bill now follows the House legislation in regards to the adjustment in the technical component discount on single-session imaging of contiguous body parts, doubling the discount to 50 percent. The utilization rate would be set to 75 percent under the House bill.
From "Senate Bill Calls for 65 Percent Equipment Utilization Rate"
AuntMinnie.com (09/16/09)
Clinical Practice
Dual-Energy Computed Tomography Proves Valuable for Visualizing Hand and Foot Tendons
Researchers at Shandong University in China conducted a study to evaluate the feasibility of visualizing hand and foot tendons by dual-energy computed tomography (CT) through analysis of 20 patients. A dozen patients were determined to be normal, while abnormality was detected in the remaining eight. Dual-energy methods are very helpful in visualizing hand and foot tendons, including the flexor pollicis longus tendon, the flexor digitorum superficialis/profundus tendon, the Achilles tendon, the extensor hallucis longus tendon, and the extensor digitorum longus tendon. Such techniques can clearly image the entire shape of the tendons and their fixation points. However, visualization was poor for the peroneus longus tendon in the sole of the foot as well as the distal ends of metacarpophalangeal joints with extensor digitorum tendons and extensor pollicis longus tendons. Visualization of lesions of tendons such as the circuitry, thickening, and adherence also was clear. The researchers concluded that dual-energy CT has great value as a technique for visualizing hand and foot tendons, and is capable of clearly depicting both anatomical structures and pathologic alterations of the tendons.
From "Initial Experience With Visualizing Hand and Foot Tendons by Dual-Energy Computed Tomography"
Clinical Imaging (10/09) Vol. 33, No. 5, P. 384; Deng, Kai; Sun, Cong; Liu, Cheng; et al.
MSCTA Is Effective for Risk Stratification of Patients With Suspected Coronary Artery Disease
Researchers performed a study to evaluate whether multislice computed tomography coronary angiography (MSCTA) has use for risk stratification of patients with suspected coronary artery disease (CAD) at intermediate pretest likelihood. The study entailed the assessment of MSCTA images for the presence of significant CAD in 316 patients with suspected CAD and an intermediate pretest likelihood, and follow-up was performed to ascertain the occurrence of an event. Twenty-eight percent of patients exhibited significant CAD, while the remaining 72 percent exhibited normal MSCTA or non-significant CAD. An event occurred in nearly 5 percent of patients during follow-up. The results of the study imply that MSCTA is very effective in re-stratifying patients into either a low or high post-test risk group for patients with an intermediate pretest likelihood.
From "Multislice Computed Tomography Coronary Angiography for Risk Stratification in Patients With an Intermediate Pretest Likelihood"
Heart (10/01/09) Vol. 95, No. 19, P. 1607; van Werkhoven, J.M.; Gaemperli, O.; Schuijf, J.D.; et al.
Small Variations Found Between Target Volume Shape in Supine and Prone Position During Irradiation of Rectal Cancer Patients
Scientists in the Netherlands measured the inter-fraction shape variation of the mesorectum for rectal cancer patients treated with 5 x 5 Gy in supine position and compared it to the variation in prone position. They report that a planning computed tomography (pCT) scan and five daily cone-beam CT (CBCT) scans were obtained for 28 patients in supine position, and the mesorectum was outlined on all scans. Shape variation was measured by the distance between the pCT and the CBCT delineations and stored in surface maps following online setup correction. The data for male and female patients was analyzed separately and compared to prone data. The researchers discovered a broad spectrum of systematic and random shape variation, comparable to prone patients. They conclude that the degree of variation between supine and prone orientation is small. The researchers advise that clinical margins should be differentiated in position along the cranio–caudal axis, in anterior–posterior direction, and for gender. Margins should also be increased, even with the employment of online setup correction. The setup option should be determined on dose to the organs at risk on account of small margin differences between prone and supine treatments, the researchers recommend.
From "Target Volume Shape Variation During Irradiation of Rectal Cancer Patients in Supine Position: Comparison With Prone Position"
Radiotherapy and Oncology (09/09) Vol. 92, No. 3, P. 202; Nijkamp, Jasper; de Jong, Rianne; Sonke, Jan-Jakob; et al.
RSNA Weekly is a briefing of the latest radiology-related news selected from hundreds of sources by the editors of Information, Inc. While care is taken to use good sources, inaccuracies in source material are not the responsibility of RSNA or Information, Inc.
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