January issue of RSNA News Now Available
Don't Miss the Latest News
The January issue of RSNA News is now available at RSNAnews.org
Highlights include:
Backlash Continues Against Breast Cancer Screening Guidelines
CT Reveals Pulmonary Embolism in Severely Ill Swine Flu Patients
International Panel Assesses Hybrid Imaging
Communication Key in Avoiding Malpractice Minefields
Headlines
Leading the News
Research
Technology
Medical-Legal Issues
Clinical Practice
Industry News
Leading the News
Brain Scan Used in Difficult Parkinson Disease Diagnoses
Idiopathic Parkinson disease can present with symptoms similar to multiple system atrophy or progressive supranuclear palsy. A recent study conducted by The Feinstein Institute for Medical Research assessed if metabolic brain imaging could be combined with spatial covariance analysis to accurately determine patients with parkinsonism with different underlying disorders. From January 1998 to December 2006, patents from the New York area with parkinsonian features and an uncertain clinical diagnosis underwent fluorine-18-labelled-fluorodeoxyglucose-PET at The Feinstein Institute for Medical Research. Researchers developed an automated image-based classification procedure to differentiate individual patients with idiopathic Parkinson disease, multiple system atrophy, and progressive supranuclear palsy. Each patient's likelihood of having each of the three diseases was calculated using multiple disease-related patterns with logistic regression and leave-one-out cross-validation. Patients were classified according to criteria defined by receiver-operating-characteristic analysis. Following imaging, patients were assessed by movement disorders specialists for a mean of two to six years before a final clinical diagnosis was made, after which the accuracy of the initial image-based classification was assessed by comparison to the clinical diagnosis. Image-based classification for idiopathic Parkinson disease had 84 percent sensitivity, 97 percent specificity, 98 percent positive predictive value (PPV), and 82 percent negative predictive value (NPV). Imaging classifications were also accurate for multiple system atrophy, with 85 percent sensitivity, 96 percent specificity, 97 percent PPV, and 83 percent NPV. Progressive supranuclear palsy was accurately identified, with 88 percent sensitivity, 94 percent specificity, 91 percent PPV, and 92 percent NPV. The study found that automated image-based classification has high specificity in distinguishing between parkinsonian disorders and could help in selecting treatment for early-stage patients and identifying participants for clinical trials.
From "Differential Diagnosis of Parkinsonism: A Metabolic Imaging Study Using Pattern Analysis"
Lancet Neurology (01/11/10) Tang, Chris C.; Poston, Kathleen L.; Eckert, Thomas; et al.
Research
Imaging Finds Problems With Visual Function in Alzheimer Patients
In patients with mild Alzheimer disease, neuronal function along the dorsal visual pathway may be altered before function along the ventral visual pathway, according to research published in the January 2010 issue of Radiology. Researchers analyzed data from 12 patients with mild Alzheimer disease and 14 age-matched healthy controls. Subjects underwent functional MRI while deciding whether two simultaneously presented faces were identical and whether two images were located in the same position within their surrounding rectangle. The researchers found that the control group had differential activation of the ventral and dorsal pathways during the facial- and location-matching tasks. Alzheimer patients recruited more regions in the dorsal visual pathway, particularly in the frontal and parietal lobes, for the location task.
From "Alzheimer Disease: Functional Abnormalities in the Dorsal Visual Pathway"
Radiology (01/01/10) Vol. 254, No. 1, P. 219; Bokde, Arun L. W.; Lopez-Bayo, Patricia; Born, Christine; et al.
Researchers Find Link Between Overlap Ratio and Orientation Measurements on Pelvic CT Scans
Researchers have concluded that a relationship between the overlap ratio and orientation measurements on pelvic CT scans could be found, but it was less strong than expected. Anteroposterior (AP) pelvic radiographs were examined for the presence of the cross-over sign, and the overlap ratio of the cross-over sign was measured. On CT scans of the same patients the "roof-edge angle" and the "equatorial-edge angle" were also calculated. A statistically significant but only weak relationship could be found between the overlap ratio of the cross-over sign and the "roof-edge angle" and between this ratio and the "equatorial-edge angle."
From "Correlation of the Cross-Over Ratio of the Cross-Over Sign on Conventional Pelvic Radiographs With CT Retroversion Measurements"
Skeletal Radiology (01/10) Werner, Clement M. L.; Copeland, Carol E.; Stromberg, Jeff; et al.
Imaging Studies Help Detect Underlying Cancers in Patients With Neurologic Symptoms
A combination of PET-CT scans of the whole body appears to detect cancer in individuals with related neurologic disorders more accurately than other common tests. Researchers analyzed the medical records of 56 consecutive patients with suspected paraneoplastic neurologic disorders whose standard evaluations, including CT alone, did not show cancer. These patients then all underwent PET-CT between 2005 and 2008. PET-CT detected abnormalities suggestive of cancer in 22 of the patients, of whom 10 had cancer diagnoses confirmed by biopsy or another method. Nine of the 10 were early stage cancers, and detection facilitated early treatment. Cancer remission was reported in seven patients and improvement in neurologic symptoms in five patients after a median of 11 months follow-up.
From "Positron Emission Tomography– Computed Tomography in Paraneoplastic Neurologic Disorders"
Archives of Neurology (01/10) McKeon, Andrew; Apiwattanakul, Metha; Lachance, Daniel H.; et al.
CT Scans Spot Many Kidney Abnormalities
Researchers report that approximately 25 percent of healthy people have abnormalities in the kidneys and their blood vessels but that most of these abnormalities are not serious enough to prevent a person from donating a kidney. In the study, researchers conducted CT scans of the kidneys and renal arteries of nearly 2,000 adults at the Mayo Clinic who volunteered to donate a kidney to a patient with kidney failure. The most common problem identified was kidney stones, which were present in about 10 percent of the participants. More than 73 percent of the abnormalities were not serious enough to prevent kidney donation.
From "Prevalence of Renal Artery and Kidney Abnormalities by Computed Tomography Among Healthy Adults"
Clinical Journal of the American Society of Nephrology (01/10) Lorenz, Elizabeth C.; Vrtiska, Terri J.; Lieske, John C.; et al.
Technology
Sliding-Thin-Slab Averaging Improves Depiction of Low-Contrast Lesions With Radiation Dose Savings at Thin-Section CT
The combination of thin-section scanning and thick-section display allows routing volumetric imaging without a general increase in radiation dose or a reduction in the detectability of low-contrast legions, finds a recent review published online in RadioGraphics on Jan. 12, 2010. Reviewers found this combination to be helpful in cases where multidetector CT must produce an image that has both high spatial resolution and low image noise. Typically, the combination of these needs would result in a high dose of radiation to the patient. The application of a sliding-thin-slab algorithm during imaging postprocessing and review helps overcome this limitation by reconstructing thicker sections with lower noise levels from thin-section data obtained using dose-saving protocols.
From "Sliding-Thin-Slab Averaging for Improved Depiction of Low-Contrast Lesions With Radiation Dose Savings at Thin-Section CT"
RadioGraphics (01/10) von Falck, Christian; Galanski, Michael; Shin, Hoen-oh
Medical-Legal Issues
New Breast Screening Limits Face Reversal
Federal guidelines released last year stated that annual mammograms may no longer be necessary. However, the final healthcare overhaul bill is likely to require coverage for more mammograms than the new guidelines recommend, largely due to women's groups, doctors, and imaging-equipment makers putting pressure on lawmakers. For years, many doctors and patient groups have supported early, frequent screening for breast cancer, and in recent years have worked with mammography companies to hold joint events to promote breast-cancer awareness. In November 2009, the U.S. Preventive Services Task Force said routine mammograms were unnecessary for women in their 40s with a normal cancer risk, arguing that the downsides of mammograms, like false positive results and exposure to low-level radiation, could outweigh the benefits for many women in this age group. In the Senate, lawmakers approved an amendment to the healthcare overhaul bill from Sen. Barbara Mikulski (D-Md.) that effectively nullifies the new guidelines and promises mammogram coverage for women starting at age 40. Just before Christmas, the House voted unanimously in approving a resolution stating that task-force guidelines should not be used by insurers to deny coverage for routine mammograms.
From "New Breast Screening Limits Face Reversal"
Wall Street Journal (01/12/10) Mundy, Alicia
Clinical Practice
CT Used to Assess Severity of Chronic Obstructive Pulmonary Disease
Researchers set out to assess the relationship between measurements of lung volume (LV) on inspiratory/expiratory computed tomography (CT) scans, pulmonary function tests (PFT), and CT measurements of emphysema in patients suffering from chronic obstructive pulmonary disease. PFT and chest CT were performed on 46 smokers at full inspiration and expiration. Open-source software automatically quantified inspiratory and expiratory LV values, and the expiratory/inspiratory (E/I) ratio of LV was calculated. Mean lung density (MLD) and low attenuation area percent were gauged as well, and the Spearman rank correlation test was employed to evaluate correlations of LV measurements with lung function and other CT indices. The results of the study indicate that LV E/I ratio can be considered equal to MLD E/I ratio and to mirror airflow limitation and air-trapping. Higher collapsibility of lung volume, exhibited by inspiratory/expiratory CT, is indicative of less severe conditions in chronic obstructive pulmonary disease.
From "Collapsibility of Lung Volume by Paired Inspiratory and Expiratory CT Scans: Correlations with Lung Function and Mean Lung Density"
Academic Radiology (01/10) Yamashiro, Tsuneo; Matsuoka, Shin; Bartholmai, Brian J.; et al.
Six Sigma Practices Improve Patient Flow for Bone Densitometry Practice
Lean Six Sigma process improvement methodologies may prove useful to radiology as a way to identify opportunities for improvement in patient care delivery settings. This conclusion is based on a 100-day quality improvement project with the guidance of a quality advisor, which was published online on January 12 in Radiographics. A multidisciplinary team used the define, measure, analyze, improve, and control (DMAIC) framework to perform time studies for all aspects of patient and technologist involvement. From these studies, value stream maps for the current state and for the future were developed, and tests of change were implemented. Comprehensive value stream maps showed that before implementation of process changes, an average time of 20.95 minutes was required for completion of a bone densitometry study. First, the location for completion of a patient assessment form was moved from inside the imaging room to the waiting area, enabling patients to complete the form while waiting for the technologist. Second, the patient was instructed to sit in a waiting area immediately outside the imaging rooms, rather than in the main reception area, which is far removed from the imaging area. These steps resulted in a 15 percent reduction in the initial patient cycle time with no change in staff or costs.
From "Improving Patient Flow for a Bone Densitometry Practice: Results from a Mayo Clinic Radiology Quality Initiative"
RadioGraphics (01/10) Aakre, Kenneth T.; Valley, Timothy B.; O'Connor, Michael K.
Industry News
FDA Warns of Excessive CT Radiation Doses
An ongoing investigation by the U.S. Food and Drug Administration shows that more than 250 patients treated at four or more facilities in two states received up to eight times the expected dose of radiation during computer-assisted tomography perfusion scans. In early October, the FDA warned health care workers that it had received reports of 206 patients receiving excess doses of radiation from computed tomographic (CT) scans over an 18-month period at Cedars-Sinai Medical Center. Since then, the agency and local health officials have identified at least 50 more affected patients, with additional cases being found at Cedars-Sinai, two other California hospitals, and at least one hospital in Alabama. FDA Center for Devices and Radiological Health (CDRH) Acting Director Jeffrey Shuren says it is unclear whether human error or design flaws in the General Electric and Toshiba machines resulted in the overdoses. Shuren says he would not be surprised to see similar incidents in other states. Some of the patients who were overexposed developed skin redness or experienced hair loss, and all of the patients may be at an increased risk of developing certain cancers or cataracts in the months or years following their scan, according to Charles Finder, associate director of the division of mammography quality and radiation programs at the FDA's CDRH. To prevent similar incidents from occurring, the FDA is urging facilities and CT technicians to redouble their efforts to ensure proper radiation levels are used. The FDA recommends facilities determine if any of their patients have received inappropriate doses, review their dosing protocols, and implement quality control measures to ensure dosing protocols are followed for every scan.
From "FDA Warning: CT Scans Exceeded Proper Doses"
Journal of the American Medical Association (01/01/10) Vol. 303, No. 2, P. 124; Kuehn, Bridget M.
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.
Abstract News © Copyright 2010 INFORMATION, INC.
Radiological Society of North America, Inc.,
820 Jorie Blvd, Oak Brook, IL 60523-2251
|
