Educational Sessions Spread Knowledge, Clinical Insight

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Computed tomography was again the talk of the 94th Scientific Assembly and Annual Meeting of Radiological Society of North America (RSNA) educational and scientific sessions and posters—noteably cardiac CT angiography, CT radiation dose safety (namely in cardiac and pediatric studies) and CT colonography. But sharing the spotlight were sessions on IT informatics and integration and breast imaging such as breast MRI, sonoelastography and positron emission tomography. Altogether, some 1,803 scientific papers and 729 scientific posters were presented, while 1,606 abstracts offered insight for education exhibits. Some of the notable presentations are summarized here. For full-length stories of these presentations and more, visit RSNA360.HealthImaging.com.

CARDIAC CTA

Researchers outline expanded role for cardiac CT

Cardiac CT continues to demonstrate its clinical utility and is likely to replace TEE in a number of indications; however, additional research is necessary to more adequately define their roles. Xiao-Chun Zhang, MD, of Sichuan University in Chengdu, China, reported that 64-slice CT can assess right ventricular systolic and left ventricular diastolic function to quantify the severity of pure rheumatoid mitral stenosis. Zhang also said that in patients with mitral regurgitation, CT measurements agreed and correlated with 3D echo and MR, and CT produced highly accurate and reproducible results for patients with pure rheumatoid mitral stenosis.

Jin Hur, MD, of Yonsei University in Seoul, South Korea, said that cardiac CT angiography offers a non-invasive and sensitive modality for detecting left atrial appendage thrombus and differentiating between thrombus and spontaneous echo contrast in stroke patients.   

Troy LaBounty, MD, of Weill Cornell Medical College in New York City, reported high intraobserver agreement on CT studies and concluded that CT may be useful in evaluating valve functioning in patients with Medtronic Hall and St. Jude valves and concluded that CT may provide useful prognostic information in patients with aortic stenosis.

Another clinical cardiac application where CT could replace TEE is pre-operative characterization of aortic valve features in patients with aortic stenosis. Baskaran Sundaram, MD, of University of Michigan in Ann Arbor, and colleagues said that aortic valve assessment using dynamic CT is feasible and determines leaflet morphology precisely.

Myocardial bridging could be risk factor for arteriosclerosis?

“Myocardial bridging in the middle left anterior descending coronary artery (LAD) may be a significant risk factor for atherosclerosis in the proximal LAD,” said Takeshi Nakaura MD, from the Kumamoto University School of Medicine in Kumamoto, Japan.  By multivariate analysis, age, sex, the presence of hypertension and myocardial bridging were “statistically significantly associated with proximal LAD atherosclerosis.” Nakaura added that  middle LAD bridging represented the highest risk for the development of coronary plaques in the proximal segment of the LAD.

Contrast-enhanced cardiac MDCT, stress MRI help detect perfusion abnormalities

Adenosine stress multidetector CT (MDCT) myocardial perfusion imaging can be successfully performed in patients with coronary artery disease (CAD) with good agreement with stress myocardial perfusion MRI. The “ability of MDCT to perform both stress perfusion imaging and coronary angiography will significantly enhance the value of cardiac MDCT study in the diagnosis and treatment of patients with CAD,” said Shingo Kato, MD, of the National Institute of Radiological Sciences in Chiba, Japan.

Quantity of intracranial calcification is not an independent predictor of stroke

Philip Homburg, MD, from Erasmus Medical Center, University Medical Center in Rotterdam, the Netherlands, said that intracranial calcification in the symptomatic artery found on a multidetector CT angiography is not independently associated with infarcts in the symptomatic hemisphere. He said that the quantity of intracranial calcification was significantly higher in the symptomatic carotid artery of patients with infarcts in the symptomatic hemisphere than in patients without infarcts in the symptomatic hemisphere. However, he noted that in a multivariate analysis after adjustment for age and sex, no independent relationship was found between the quantity of intracranial calcification in the symptomatic artery and infarcts in the symptomatic hemisphere.  

IMAGING INFORMATICS

Advanced viz, image transmission critical to dealing with info overload

Bradley Erickson, MD, PhD, of Mayo Clinic in Rochester; Minn., Paul Chang, MD, of the University of Chicago, and Geoffrey D. Rubin, MD, of Stanford University, in Stanford, California, agree that multidetector isotropic volumetric CT and advanced MR sequences have created an explosion in the number of images to be reviewed for diagnostic interpretation. One strategy to combat image overload, Erickson suggested image alignment because it makes it easier to compare studies and sequences and reduces busy work—however, it does not reduce the amount of information. Change detection and segmentation are two other strategies. Chang detailed advanced visualization tools as well as the movement away from the hierarchical storage models for PACS toward on-demand archive. However, he noted that storage is not the problem—the fundamental problem with managing these large image data sets is the transmission to modalities and 3D workstation or to the server of the client-server environment.

Patient photos spur radiologist empathy, eye for detail

Including a patient’s photo with imaging exam results may enable a more meticulous reading from the radiologist interpreting the images, as well as a more empathetic approach. Yehonatan N. Turner, MD, from Zedek Medical Center in Jerusalem, said it is important to counteract the anonymity that is common in radiologic exams, especially with the growth of teleradiology.

He and colleagues found that after interpreting the results of CT exams, radiologists admitted feeling more empathy towards the patients after viewing their photos. Most importantly, the results showed that radiologists provided a more meticulous reading of medical image results when a photo of the patient accompanied the file, Turner said.

Building a proactive IT support structure

Bringing IT and radiology to the same page serves as the starting point for effective IT support, which can be reactive or proactive, according to Paul Nagy, PhD, from the University of Maryland Medical Center in Baltimore. The IT department needs to build systems and processes to facilitate proactive support and system monitoring. Nagy’s department developed a web-based problem management system and uses a blog to streamline communication; all actions and resolutions are tracked and communicated to the submitter and IT staff, he added. “Proactive monitoring adds value to IT operations by extending problem management structure,” he said.

CaBIG delivers federated access to imaging informatics toolkit

A collection of imaging informatics tools developed by the National Cancer Institute’s caBIG (cancer Biomedical Informatics Grid) are demonstrating the potential for collecting, analyzing, integrating and disseminating information associated with cancer research and care, said Eliot L. Siegel, MD, from the University of Maryland School of Medicine in Baltimore. He reported that developers and researchers have made excellent progress over the past 12 months. The Network for Translational Research and Clinical Trial Tools Integration projects are adoption efforts that aim to show the efficacy of the tools and standards developed by the caBIG imaging workspace across the clinical continuum. “This year’s emphasis has been on practical implementations of the software for use in ongoing research projects,” Siegel said.

BREAST IMAGING & THERAPY

Positron emission mammography could be effective in detecting breast cancer

“The sensitivity of PEM [positron emission mammography] is equal to or better than breast MRI, and has fewer false-positive results,” said Kathy Schilling, MD, from the Center for Breast Care at Boca Raton Community Hospital in Florida.  In the study of 208 patients, 189 malignant lesions were imaged with PEM detecting 176 for an overall sensitivity rate of 93 percent. PEM successfully detected cancer in 100 percent of fatty breasts, 93 percent of dense breasts, 85 percent of extremely dense breasts, 93 percent of women both with and without a history of hormone replacement therapy, 90 percent of pre-menopausal women and 94 percent of post-menopausal women. PEM produces just 48 images that can be correlated with a mammogram.

New statistical model could help reduce breast lesion biopsies

Wendy DeMartini, MD, from the Seattle Cancer Care Alliance and colleagues have developed a preliminary statistical model that breast radiologists could use when deciding whether a lesion found on breast MRI is likely to be malignant or benign. This could be beneficial because MRI exams are so sensitive that they reveal cancerous and non-cancerous lesions that often look alike and behave similarly when contrast dye is injected, she said. Lesions found in women undergoing MRI to look for additional malignancy after new breast cancer diagnosis that were larger than 1 centimeter, and whose enhancement quickly washes out were the most likely to be malignant.

Brachytherapy offers alternative to breast cancer patients with implants

Women with early-stage breast cancer who have undergone breast augmentation may be treated successfully with brachytherapy, partial-breast radiation treatment. Patients treated with brachytherapy have better cosmetic outcomes and avoid the risk of the implant hardening, compared to patients who undergo whole-breast radiation therapy, according to Robert R. Kuske Jr., MD, from the University of Arizona Health Sciences Center and the Arizona Oncology Services in Scottsdale, Ariz. He said that one in eight women who undergo breast augmentation (347,500 women in 2007; a 64 percent increase since 2000) will develop breast cancer at some point in their lives.

Breast-specific gamma imaging could target hard-to-detect cancers

Breast-specific gamma imaging (BSGI) is effective in the detection of cancers not found on mammograms or by clinical exam, Rachel F. Brem, MD, of the George Washington University Medical Center in Washington, D.C.

“BSGI can identify the most difficult to detect breast cancer—invasive lobular carcinoma,” said Brem. “It also can help us detect additional lesions of all types of breast cancer in women whose mammograms show only one suspicious lesion.” While mammography findings are characterized by the difference in appearance between normal and suspicious breast tissue, BSGI findings are based on how cancerous cells function. BSGI is meant to be used as an adjunct to mammography.

CT COLONOGRAPHY

CT colonography could offer one-stop screening for cancer and osteoporosis

CT colonography (CTC) has the potential to screen for two diseases at once—colorectal cancer and osteoporosis—both of which commonly affect adults over age 50, according to study results.

The study’s lead author Rizwan Aslam, MB, from the University of California, San Francisco, said that by using CTC images, another software application can create 3D images of the spine, allowing bone mineral density, usually associated with osteoporosis, to be measured. “When an individual undergoes CT colonography, we can also obtain a bone density measurement with no additional radiation and at minimal cost,” Aslam said.

Referring physician input guides CT colon report format

When it comes to clinician-to-clinician service offerings, simply asking what they want can provide a better quality of medical communication, as well as deliver improved patient care, according to a Mayo Clinic initiative that set out to develop a structured report format to communicate CT colonography (CTC) results to referring clinicians. Using “C-RAD” proposals from the Working Group on Virtual Colonoscopy as a starting point, the team reconfigured the C-RAD report format to present colonic findings, in all capital letters, first. A paragraph break followed and extracolonic findings were presented next. Technique followed another paragraph break, and comprised the third element presented in the report. The new format was then sent out, along with the traditional format currently in place at the facility to a broad group of referring clinicians.

Panoramic 3D offers new CT colon efficiencies

As CT colonography (CTC) gains wider acceptance as an effective and less-invasive exam for colon cancer screening, advanced visualization tool development is keeping pace by offering applications that will allow interpreting clinicians the ability to efficiently and effectively manage the virtual colonoscopy workflow. Dipti K. Lenhart, MD, of New York University Medical Center in New York City assessed the evaluation times and accuracy of unidirectional panoramic 3D interpretation to traditional 2D and bi-directional 3D endoluminal techniques.

Among the three readers, 2D interpretation had a mean time of 8.85 minutes; endoluminal 3D clocked in at 14.74 minutes; and panoramic 3D took 12.19 minutes. “Primary 2D interpretations are quicker than 3D, but sensitivity for 2D is significantly lower,” Lenhart noted. “Panoramic and traditional 3D techniques have similar sensitivity and specificity, with panoramic interpretation requiring significantly less time.”

Low-dose protocol doesn’t affect 3D CTC

Although the diagnostic quality of 2D images produced by ultra low-dose CT colonography (CTC) is not affected by the radiation-lowering protocol, questions have remained as to its applicability with 3D advanced visualization software tools. Mehdi Cadi, MD, of the Saltpietre Hosipital in Paris, said that the quality of images for CTC 3D interpretation (polyps and masses) is not affected by low-dose protocols.

Training could ease perception errors with CTC virtual dissection

“Optimal CTC interpretation incorporates both 2D and 3D search techniques as some polyps are more conspicuous using one display method,” said Kevin Christensen, MD, of Mayo Clinic in Rochester, Minn. “3D virtual dissection allows a 360 degree view of the flattened colonic lumen, providing a rapid 3D visualization method, but is associated with anatomic distortion.” He observed that the most common cause for false-negative interpretations at both primary 2D and 3D virtual dissection search is perceptual error; and the most commonly missed finding was an adenoma of less than 1 cm on both visualizations. However, the researchers believe that false-negatives on 3D virtual dissection can be reduced with proper interpretative training on the application.

MOLECULAR IMAGING

FDG PET/CT outperforms whole-body MRI in staging cancer patients

FDG PET/CT improves staging accuracy in cancer (colorectal, breast, lung cancer and lymphomas) patients compared with whole-body 3T MRI (WBMR), according to a study presented by Ettore Squillaci, MD., of the University of Rome. In comparing the accuracy of PET/CT with whole-body MRI in staging different malignant diseases, fused PET/CT proved significantly more accurate in assessing the overall TNM stage compared to CT alone, side-by-side CT plus PET and WBMR. The researchers found that of all 60 patients, 90 percent were correctly staged with PET/CT; 70 percent with side-by-side CT plus PET; 63 percent with CT alone and 60 percent with WBMR. No statistically significant difference could be detected between PET/CT and CT plus PET in assessing M-staging. Combined PET/CT had an impact on the treatment plan in three patients compared with whole-body MRI.

FDG PET/CT brings accuracy to staging, restaging of prostate cancer

FDG PET/CT may add significant value in patients with prostate cancer by accurately identifying primary lesions and/or metastases at initial staging and detecting recurrent disease according to research by Nghi C. Nguyen, MD, PhD, of St. Louis University in Missouri. “FDG PET/CT may add significant value in patients with prostate cancer by accurately identifying primary lesions and/or metastases in 48 percent at initial staging, detecting recurrent disease in PSA+ patients in 42 percent as well as incidentally diagnosing a second primary in at least 2 percent,” the authors concluded.

Needed: Nuclear medicine advanced associates

Nuclear medicine has grown tremendously in the last 15 years, creating the need for a new clinical specialty—nuclear medicine advanced associates, said David Gilmore, from Beth Israel Deaconess Medical Center in Boston. The new title—nuclear medicine advanced associate—represents an advanced practice level.

The master’s degree program is designed to prep participants to serve as a physician extender with duties ranging from radiopharmaceutical administration, performing stress tests and ordering complementary exams to clinical leadership. The initial program is a collaboration among University of Arkansas School for Medical Sciences, St. Louis University and University of Missouri.