By Eric Barnes, staff writer
November 3, 2015

As RSNA 2015 turns a sprightly 101 this year, CT continues to pull tricks out of what always seems like its bottomless hat. In 2015, the all-purpose modality is doing its old tricks better than ever, and it's pulling off some new ones that hadn't seen much play before.

This year, for example, x-ray phase-contrast CT is being highlighted along with its magician-like ability to detail soft-tissue structures that mere photons couldn't seem to generate before. Researchers are developing algorithms to extract phase image information more efficiently as well, such as a phase-stepping procedure to efficiently extract signals.

Other quantitative CT techniques are gaining prominence, too. An investigational photon-counting CT scanner has recently taken up residence at the Mayo Clinic in Rochester, MN, opening the door to scans that can highlight a single very specific material. Not incidentally, the new scanner has generated a number of studies for this year's RSNA 2015 meeting, including one presentation on a special iterative reconstruction technique that removes the extra image noise that photon counting adds.

Lung cancer screening with CT is always a big draw at the meeting. A new study from the Netherlands looks at improving the nodule risk-classification schemes such as Lung-RADS with morphological information. Researchers from Boston ponder how lung cancer screening has changed at top academic centers in just two short years. Another study looks at how many people never come back after their first CT scan -- and why. Finally, investigators from Japan put contrast-enhanced dual-energy CT (DECT) head to head with PET/CT to distinguish benign from malignant lung nodules.

In the heart, spectral CT is being combined with biomarkers in a bid to determine the composition of coronary artery plaque and to see if it's possible to predict which lesions are prone to rupture.

In pancreatic cancer, researchers are measuring treatment response based on iodine uptake, not just tumor volume changes, in dual-energy CT.

Another group is using material decomposition CT to distinguish myriad lung abnormalities, while a third group applied a material decomposition algorithm to distinguish hemorrhage from calcifications in small hyperdensities commonly seen on admission CT in stroke patients.

Throughout the body, iterative reconstruction keeps improving its performance in the task of minimizing dose and maximizing image quality in everything from radiofrequency ablation for atrial fibrillation to characterizing hepatic metastases with ever-smaller radiation doses.

Speaking of radiation, size-specific dose estimates have become the dose-optimization method of choice. But do these dose estimates work with tube current modulation? Find out in a CT physics scientific session.

Among the many general topics to be explored at RSNA 2015, Dr. Max Wintermark from Stanford University leads a discussion on stroke triage.

And radiology luminary Dr. James Thrall from Massachusetts General Hospital in Boston ties it all in a bow with his plenary talk on Tuesday afternoon on the future of radiology -- i.e., the peril and the promise poised to unfold before us.

To view RSNA's complete listing of abstracts for this year's scientific and educational program, click here.

Scientific and Educational Presentations
Certain COPD phenotypes more often associated with lung cancer
Sunday, November 29 | 10:45 a.m.-10:55 a.m. | SSA04-01 | Room S404CD
Chronic obstructive pulmonary disease (COPD) is a well-known risk factor for lung cancer. But do some COPD phenotypes carry a greater risk of malignancy?
Photon-counting CT: Dose comparison with conventional CT
Sunday, November 29 | 10:55 a.m.-11:05 a.m. | SSA19-02 | Room S403B
In this talk, researchers will discuss their efforts to compare dose efficiency between an investigational photon-counting CT scanner and conventional CT.
Can lung nodule scoring systems do better?
Sunday, November 29 | 11:05 a.m.-11:15 a.m. | SSA04-03 | Room S404CD
The rise of CT lung cancer screening has been accompanied by a few published lung nodule scoring systems, including Lung-RADS and the McWilliams model. But could the models be tweaked to perform better?
Spectral CT works for analyzing plaque composition
Sunday, November 29 | 11:35 a.m.-11:45 a.m. | SSA02-06 | Room S502AB
Can spectral CT determine the type of coronary plaque and even its vulnerability to rupture? It can, according to researchers in China.
DECT measures treatment response in pancreatic cancer
Sunday, November 29 | 11:45 a.m.-11:55 a.m. | SSA06-07 | Room E353A
Tumor volume often falls significantly after chemotherapy, but the drop in iodine uptake may be more significant for prognosis. A group from Johns Hopkins University measured treatment response using iodine uptake with dual-energy CT (DECT) before and after treatment of pancreatic cancer.
3D CT with advanced iterative recon aids ablation procedures
Sunday, November 29 | 12:30 p.m.-1:00 p.m. | CA210-SD-SUA1 | Lakeside Learning Center, Station 1
In this study, Dr. Gianluca Pontone and colleagues from Centro Cardiologico Monzino in Milan compared two demographically similar groups using CT of the left atrium with first- and second-generation iterative reconstruction.
Storing raw CT data may cut unnecessary repeat studies
Sunday, November 29 | 12:30 p.m.-1:00 p.m. | IN205-SD-SUA6 | Lakeside Learning Center, Station 6
Researchers from Yale University will show in their poster presentation how retaining raw CT data may enable radiologists to reduce the number of unnecessary repeat CT scans being performed on patients.
Refresher course tackles pulmonary embolism CT optimization
Monday, November 30 | 8:30 a.m.-8:55 a.m. | RC208-01 | Room S102AB
This refresher course on optimizing CT for pulmonary embolism will review a number of practical radiation dose reduction techniques.
How many CT lung cancer screening patients return after the 1st scan?
Monday, November 30, 2015 |10:50 a.m.-11:00 a.m. | RC201-09 | S406B
In this study, researchers assessed patient compliance with follow-up recommendations in a CT lung cancer screening program.
Tube current modulation vs. size-specific dose estimates
Monday, November 30 | 10:50 a.m.-11:00 a.m. | SSC10-03 | Room S504CD
Size-specific dose estimates (SSDEs) are credited with bringing new levels of accuracy to radiation dose estimates by allowing dose to be tailored to patient size in a straightforward way. But how well SSDE works with automated tube current modulation, another mainstay of CT imaging, is still up for debate.
CT lung cancer screening evolves at major academic centers
Monday, November 30 | 11:20 a.m.-11:30 a.m. | RC201-11 | Room S406B
Major changes have come to CT lung cancer screening in the past two years, and the results of a survey of major academic centers highlights both modest increases in screening volumes and a move away from self-pay screening.
What does YouTube say about radiation safety?
Monday, November 30 | 12:15 p.m.-12:45 p.m. | HP208-SD-MOA3 | Lakeside Learning Center, Station 3
Cat videos, daredevils, style mavens: You'll find them all on YouTube. But what does the wildly popular video site have to say about radiation safety and risks?
Multiphase CT enterography finds obscure GI bleeds
Monday, November 30 | 3:00 p.m.-3:10 p.m. | SSE08-01 | Room E353C
Multiphase CT enterography is an effective option for detecting the source of gastrointestinal (GI) bleeds, according to this study to be presented on Monday afternoon.
Photon-counting CT algorithm cuts noise in multienergy CT
Monday, November 30 | 3:00 p.m.-3:10 p.m. | SSE22-01 | Room S403B
In this scientific session, researchers from the Mayo Clinic in Rochester, MN, will discuss their use of a new algorithm to reduce noise in multienergy CT scans.
Review course: Today's stroke triage tools
Tuesday, December 1 | 8:30 a.m.-8:55 a.m. | RC305-01 | Room N230
How are today's neuroradiologists handling stroke triage? Perfusion CT and perfusion-weighted MRI can assess for ischemic stroke, hemorrhage, vasospasm, brain tumors, seizures, and traumatic brain injury. But not everything is appropriate for every case, according to Dr. Max Wintermark from Stanford University.
DECT differentiates lung lesions with material decomposition
Tuesday, December 1 | 11:10 a.m.-11:20 a.m. | SSG03-05 | Room S404CD
In this study, researchers from Boston investigated the characteristics of lung abnormalities seen on material decomposition images from dual-energy CT (DECT).
What's the minimum CT dose for hepatic metastasis detection?
Tuesday, December 1 | 11:20 a.m.-11:30 a.m. | SSG05-06 | Room E352
How low can the CT radiation dose go for hepatic metastasis detection when using advanced iterative reconstruction? Investigators from the Mayo Clinic in Rochester, MN, wanted to see how low advanced iterative reconstruction would take them.
Phase-contrast CT technique reveals hidden image information
Tuesday, December 1 | 11:40 a.m.-11:50 a.m. | SSG14-08 | Room S403B
New developments in phase-contrast CT imaging have some investigators intrigued about the potential of x-ray-based techniques to reveal previously unseen information. Researchers from Emory University will share their thoughts in this Tuesday session.
DECT technique separates benign from malignant lung nodules
Tuesday, December 1 | 11:50 a.m.-12:00 p.m. | SSG03-09 | Room S404CD
While CT is good at detecting lung nodules, PET/CT is better at determining whether they are malignant or benign. Researchers from Kobe, Japan, wanted to see if their CT technique, known as dual-point contrast-enhanced dual-energy CT (DECT), could rival PET/CT for predicting malignancy.
Radiology's future combines tech innovation and productivity tools
Tuesday, December 1 | 1:30 p.m.-2:45 p.m. | PS30C | Arie Crown Theater
What does the future hold for radiology? Get ready for a cascade of sometimes conflicting trends -- all leading toward a more complex and better diagnosed future, according to a Tuesday plenary talk by radiology luminary Dr. James Thrall.
For ischemic stroke, CT perfusion boosts detection in posterior circulation
Tuesday, December 1 | 3:10 p.m.-3:20 p.m. | SSJ18-02 | Room N226
There is still no consensus about the best way to image the posterior circulation in the setting of ischemic stroke, but researchers in Münster, Germany, have found significant value in CT perfusion.
Monoenergetic images vs. calcium blooming in CCTA
Wednesday, December 2 | 11:50 a.m.-12:00 p.m. | SSK04-09 | Room S504AB
Calcium blooming in coronary CT angiography (CCTA) images makes calcium appear larger than its actual size, exaggerating the extent of luminal stenosis and producing false-positive tests, which can lead to inappropriate clinical management, according to this study to be presented on Wednesday.
Noncontrast head CT takes on small hyperdensities
Wednesday, December 2 | 3:50 p.m.-4:00 p.m. | SSM07-06 | Room S403B
In the emergency room, noncontrast head CT scans often reveal hyperdensities that could represent small parenchymal hemorrhages or calcifications. Much of the time, but not always, the two can be differentiated by morphology and location. But is the standard practice of waiting six hours to repeat the head CT scan to assess stability the best way to solve the remaining mysteries?
Tin filters and lung nodule CT at x-ray exposure levels: Accurate?
Thursday, December 3 | 11:10 a.m.-11:20 a.m. | SSQ19-05 | Room S403B
How well does CT equipped with a tin filter measure lung nodule volumes at radiation dose levels similar to those of a chest x-ray? Pretty well, most of the time, Mayo Clinic researchers will report in this Thursday presentation.
Gaze tracking uncovers nodule detection patterns
Thursday, December 3 | 11:30 a.m.-11:40 a.m. | SSQ04-07 | Room E351
In this scientific session, researchers from Duke University will share their findings on how radiologists detect lung nodules while reading CT studies.