Road to RSNA 2016: CT Preview

By Eric Barnes, staff writer
November 1, 2016

At RSNA 2016, CT will mark another year of progress in grabbing useful information from anatomy scanned at ever-lower radiation doses. Clinicians will increasingly rely on CT as they search for the image data that will nail a difficult diagnosis or chart a course to treatment that will improve patient survival.

Physicians are being aided in their search by radiomics -- the science of extracting quantitative information from imaging data that has mined CT's fertile ground to the point where it can deliver information that might previously been reserved for MRI or nuclear medicine -- or simply not available at all.

Spectral imaging, iodine imaging, k-edge imaging, photon-counting CT, iterative reconstruction, and other quantitative imaging techniques are on display in this year's sessions, offering new ways to see data hidden inside images. To take just one example, metastatic epidural spinal cord compression is a critical finding impacting survival, and quantitative CT can find it.

Also boosting quality of care are new CT hardware and software techniques that portend a faster, higher-resolution future, with a new high-resolution CT detector, for example, that captures 0.25 mm of data rather than the standard 0.5 mm for image resolution of up to 140 microns. New model-based iterative reconstruction techniques continue to capture more information with less dose.

One group is waging the image information battle with photon-counting CT, aided by k-edge imaging, to get a better look at stents. There are automated tube current modulation schemes that can cover thicker anatomy without going overboard on dose. And there are myriad ways to detect liver lesions at ultralow doses. One session at RSNA 2016 will describe a contest in which no fewer than 90 groups vied to offer the best method for lesion detection.

Another team is using spectral-shaping CT with tin filtration to get more image data from low-dose scans of obese patients. Iodine quantification is finding more applications that measure material composition, and investigators are probing its accuracy in quantifying iodine.

Functional cine CT of the heart had been all but sidelined owing to its high radiation dose. But when the technique is modified to incorporate scan delays long enough to capture image data from recirculated contrast, a fraction of the standard dose is enough to give new life to cine studies of cardiac function in the ventricles. In chest CT, scans lasting less than a quarter of a second are being used to quiet squirming children, with scans free of motion artifacts in nearly 100% of cases.

So much remains to be done. Researchers have noted that osteoarthritis research could benefit greatly if there were a better technique than digital x-ray absorptiometry to evaluate the subchondral bone. Now there is. Bone mineral density may be key to understanding the disease because it is related to load transmission.

For radiologists in Brazil, Florida, and elsewhere facing a deadly and debilitating virus that strikes pregnant women and their infants, a session on what radiologists need to know about Zika will explain CT's growing role in the disease.

Lung cancer research is finding new answers in its quest to assess nodule malignancy as thoroughly as possible before intervention. One study finds new clues in nodule features, while another sees the time of detection as potentially integral to the diagnosis.

One study looks at scans of transferred trauma patients and finds them mostly unreliable. Other sessions look at dose registries, dose measurement schemes, and new ways to incorporate organ doses into daily practice.

To view RSNA's complete listing of abstracts for this year's program, click here. But we invite you to browse through the links below to learn more about a couple dozen sessions that caught our eye. To be sure, it's only a sliver of the iceberg you're sure to run into in your own exploration. But in our eyes, the vast range of potential discoveries is what keeps RSNA among the world's great medical meetings. Enjoy!

Scientific and Educational Presentations
Are CT reports transferred with trauma patients unreliable?
Sunday, November 27 | 10:45 a.m.-10:55 a.m. | SSA06-01 | Room N226
Radiologists from a level I trauma center wondered if the CT reports they were getting for patients transferred to their emergency department were accurate. Their six-month investigation didn't deliver much confidence in the original reads.
Web-based CT protocol system untangles CT protocol knot
Sunday, November 27 | 10:45 a.m.-10:55 a.m. | SSA20-01 | Room S403B
Managing CT protocols, especially at a large institution, can be an unwieldy task. But researchers from the Mayo Clinic in Rochester, MN, tamed the beast with a web-based protocol management system.
FFR-CT is formidable in reducing unnecessary invasive angiography
Sunday, November 27 | 11:15 a.m.-11:25 a.m. | SSA04-04 | Room S504AB
Belgian radiologists tested noninvasive fractional flow reserve CT (FFR-CT) to find out if it really reduced unnecessary invasive angiographies in chest pain patients undergoing coronary CT angiography. Their answer was yes, emphatically.
Low-dose 4D cardiac CT protocol makes procedure viable
Sunday, November 27 | 11:35 a.m.-11:45 a.m. | SSA03-06 | Room S502AB
Is it time for another look at functional 4D cardiac CT? Researchers from Japan proposed a cine cardiac CT scheme that permits accurate assessment of left-ventricular function at an extraordinarily small dose.
90 sites compete in low-dose liver lesion detection
Sunday, November 27 | 11:35 a.m.-11:45 a.m. | SSA20-06 | Room S403B
Leading medical and physics societies created a contest to compare iterative reconstruction and denoising techniques in low-dose CT for liver lesion detection. Facilities in 26 countries took up the challenge, according to this presentation from the Mayo Clinic in Rochester, MN.
How does tube current modulation affect CT lung cancer screening dose?
Sunday, November 27 | 11:35 a.m.-11:45 a.m. | SSA21-06 | Room S404AB
Researchers from the University of California, Los Angeles designed a project to measure effective and organ radiation doses in lung cancer screening studies using tube current modulation. They found very low doses overall.
Canadians study changing approaches to suspected acute appendicitis
Sunday, November 27 | 12:05 p.m.-12:15 p.m. | SSA06-09 | Room N226
As imaging for suspected appendicitis continues to evolve, researchers in Ontario, Canada, sent questionnaires to centers across the country to find out how they were handling these patients. Among the findings: Ultrasound is often the first choice for diagnosing younger patients.
What radiologists need to know about the Zika virus
Monday, November 28 | 7:15 a.m.-8:15 a.m. | SPSH21 | Room E450B
This Hot Topic Session will consist of five presentations on topics such as the role of the radiologist in Zika infection, prenatal imaging findings of congenital Zika infection, pathological correlation with imaging findings, and an update on prevention and vaccination.
Deep learning can detect osteoporosis on CT exams
Monday, November 28 | 12:15 p.m.-12:45 p.m. | IN212-SD-MOA3 | Lakeside, IN Community, Station 3
Artificial intelligence based on deep-learning techniques may be able to automatically screen for osteoporosis in routine abdominal CT exams, according to this poster presentation.
The dubious value of lead aprons
Monday, November 28 | 3:10 p.m.-3:20 p.m. | SSE21-02 | Room S403A
Are lead aprons really helpful for reducing scatter radiation from CT? A study from the Mayo Clinic in Rochester, MN, casts doubt on the utility of shields placed outside the scan region.
Multispectral CT offers new clarity for cardiovascular imaging
Tuesday, November 29 | 7:15 a.m.-8:15 a.m. | SPSH30 | Room E352
This Tuesday Hot Topic Session will offer a comprehensive review of the technical and clinical aspects of various types of spectral CT imaging, including established techniques such as dual-source and rapid kVp switching, and emerging techniques such as split-beam CT, spectral detector CT, and photon counting.
Kids breathe freely without sedation for high-resolution chest CT
Tuesday, November 29 | 9:00 a.m.-9:10 a.m. | RC313-03 | Room N228
Squirming children are a constant concern in the CT suite, but researchers from Lille, France, scanned more than 300 children with a low-dose free-breathing protocol that delivered excellent image quality.
Spectral photon-counting CT, k-edge imaging boost stent analysis
Tuesday, November 29 | 11:00 a.m.-11:10 a.m. | SSG12-04 | Room S403B
In this presentation, researchers will discuss the added value of spectral CT and k-edge imaging in the assessment of stented vessels to reduce artifacts.
Study measures accuracy of iodine quantification
Tuesday, November 29 | 11:20 a.m.-11:30 a.m. | SSG12-06 | Room S403B
The accuracy of iodine quantification is becoming a critical question as researchers rely increasingly on dual-energy CT to quantify the composition of scanned materials. Researchers tested three different scanners to find out how well they do the job.
Organ-based dose modulation tames a high-dose CT exam
Tuesday, November 29 | 11:30 a.m.-11:40 a.m. | SSG04-07 | Room E352
An organ-based dose modulation system enables reduction of CT liver doses by one-quarter or more, with no reduction in image quality, say researchers from France.
Technique uses CT to assess subchondral bone density
Tuesday, November 29 | 11:30 a.m.-11:40 a.m. | SSG09-07 | Room E450B
Researchers from Switzerland have found a way to evaluate bone mineral density in the subchondral bone using high-resolution CT, paving the way to better understanding of osteoarthritis, leading to treatment or a cure.
Myocardial fat offers protective shield
Tuesday, November 29 | 3:40 p.m.-3:50 p.m. | SSJ04-05 | Room S504AB
Myocardial fat on CT images has long been thought to be a bad thing, so researchers in New York City were surprised to find just the opposite in 1,000 patients: enhanced survival and potentially a readjusted risk profile.
Perfusion CT predicts treatment response, survival in HCC
Wednesday, November 30 | 10:30 a.m.-10:40 a.m. | SSK06-01 | Room E353A
CT perfusion imaging offers early biomarkers for hepatocellular carcinoma (HCC) patients being treated with the kinase inhibitor sorafenib, helping doctors quickly determine who will survive longer and who is not being helped by the drug, say researchers in Japan.
Time of detection matters in lung nodule malignancy
Wednesday, November 30 | 3:00 p.m.-3:10 p.m. | SSM05-01 | Room S404AB
In a study that analyzed the risk of malignancy of screen-detected solid lung nodules, researchers from the Netherlands found that nodule size remains by far the most important predictor of malignancy. But when a nodule is discovered also matters.
Volume wins again in epidural spine metastases
Wednesday, November 30 | 3:20 p.m.-3:30 p.m. | SSM18-03 | Room N229
Epidural spine metastases are defined as a radiologic critical finding because any delay in reporting may result in substantially increased morbidity. But how can imaging be optimized to find more of them?
Is SSDE best for tracking dose in low-dose CT lung cancer screening?
Thursday, December 1 | All day | PH107-ED-X | Lakeside, PH Community
Can size-specific dose estimates (SSDEs) be considered the preferred dose index for detectability in lung cancer screening? This collaborative exhibit between Japanese and U.S. researchers explores the suitability of SSDE for dose assessment in lung cancer screening.
How to image obstructive coronary artery disease
Thursday, December 1 | 8:30 a.m.-10:00 a.m. | RC603 | Room E351
This review course gets to the heart of coronary disease, the malady underlying most cardiac morbidity, mortality, and expense. It includes a state-of-the-evidence talk, a discussion of CT myocardial perfusion imaging, and even two talks on MRI of coronary disease.
Spectral shaping delivers low-dose diagnostic chest CT in obese patients
Thursday, December 1 | 10:30 a.m.-10:40 a.m. | SSQ03-01 | Room E351
Spectral shaping with tin beam filtration can improve thoracic CT in large adults weighing more than 90 kg, according to this Thursday morning presentation.
Lung nodule assessment model sorts benign from malignant
Friday, December 2 | 10:40 a.m.-10:50 a.m. | SST03-02 | Room E451B
Is there a better tool than the radiologist's eye to determine whether a CT-detected lung nodule is benign or malignant? There might be. In this study, researchers put a promising nodule discrimination model in a controlled observer study.