Ditch x-ray to diagnose COPD, study finds

May 26, 2017 -- In the quest to diagnose mild-stage chronic obstructive pulmonary disease (COPD), radiologists often use chest radiographs, but Dutch researchers of a new study advise that they shouldn't do so because it results in substantial overdiagnosis.

The researchers performed a retrospective, nested case-control study of patients who underwent both spirometry and chest radiography to compare the diagnostic accuracy of the latter. They compared only a subset of the controls from the cohort to the incident cases. The team, led by Dr. Annemarie den Harder, a radiologist and doctoral candidate at the University Medical Center Utrecht in the Netherlands, found chest radiographs resulted in a sensitivity of 10% (European Journal of Radiology, 9 May 2017 ).

Preoperative posteroanterior and lateral chest radiographs of a 79-year old woman scheduled for mitral valve replacement. All three observers scored this patient as having COPD, while the spirometry did not diagnose COPD. All images courtesy of Dr. Annemarie den Harder.

"This study has raised the awareness at our institution that it is very challenging to diagnose COPD based on a chest radiograph," she wrote in an email to AuntMinnieEurope.com. "Therefore, we discourage our colleagues and general radiologists to mention suspicion of COPD in chest radiograph reports. We did not quantify the influence on reporting, but from our experience we think that COPD is mentioned less often in the reports after this study."

Why chest x-ray?

Chronic obstructive pulmonary disease is usually diagnosed and classified by spirometry. However, in patients with respiratory symptoms, a chest radiograph is generally the first test performed, and, thus, radiologists often mention COPD, frequently as an incidental finding.

"The largest challenge is that chest radiographs are made very often for a large variety of indications," den Harder noted. "In our hospital, around 20% of all radiological examinations are a chest radiograph."

Could that use rate of routine, preoperative chest radiographs translate into detecting mild COPD without overdiagnosis? That's precisely what the researchers sought to determine.

Their study included 783 patients referred for cardiothoracic surgery who routinely received preoperative chest radiographs and spirometry on the same day. However, they included only patients with stage I and II COPD, leaving 155 cases.

The researchers defined COPD using the Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification system. They used a digital flat-panel detector system with a tube potential of 125 kV and determined the mAs value using automated exposure control. Both a posteroanterior (PA) and a lateral chest radiograph were acquired for each patient.

Two senior radiology residents and one board-certified chest radiologist with more than 10 years of experience in thoracic radiology assessed for COPD signs on the radiographs. Observers were blinded for COPD status and did not have access to clinical information. To assess interobserver variability, each of the three observers scored 30 randomly selected patients. All observers scored overall appearance of the chest radiographs specific for COPD.

The implications

The researchers found 20% (155/783) of the patients had mild-stage COPD. For the board-certified radiologist, the positive predictive value (PPV) for overall appearance of the chest radiograph specific for COPD was 55%, negative predictive value (NPV) was 84%, sensitivity was 27%, and specificity was 95%. Only 26% (41/155) of the COPD cases were detected, while a similar proportion of 22% (34/155) of the patients without COPD were wrongly classified as having COPD.

"In routine clinical practice, we think it is important in diagnosing COPD as an incidental finding to reach a high PPV to prevent substantial overdiagnosis," the authors wrote. "This can be achieved when only patients with a predicted probability of 0.97 or higher are classified as having COPD."

Doing so would result in a PPV of 100%, NPV of 82%, sensitivity of 10%, and a specificity of 100%, making it possible to detect 10% of patients with mild COPD without any false positives.

"However, as soon as more COPD patients are detected by also classifying patients with a lower predicted probability as having COPD, this results in a disproportionally large increase in the number of false positives because the PPV rapidly declines with smaller predicted probabilities," they added.

It's clear from the results that performance of chest radiography for diagnosing mild COPD is limited.

"Based on the findings of this study, specialists and general practitioners should be aware of the limited diagnostic value of chest radiographs for COPD," the authors wrote. "This should be discussed with patients to prevent unnecessary anxiety, and confirmation with spirometry should be obtained when COPD is mentioned in chest radiography reports."

Better still, don't mention suspicion of COPD in chest radiography reports at all: "It is possible to detect COPD patients in some extent; however, this will result in substantial overdiagnosis, which is associated with a waste of resources on unnecessary care," they added.

Den Harder and colleagues are performing several other studies on COPD imaging, but using CT instead of conventional imaging, including a large multicenter study that investigates the use of a chest CT instead of a conventional chest radiograph prior to cardiac surgery (the CRICKET study).

3D printed polymer stents evolve

May 30, 2017 -- A new 3D printed polymer stent overcomes many of the limitations of conventional nitinol stents for use with tissue-engineered heart valves, offering the potential of use in children, according to an article in 3D Printing and Additive Manufacturing.

Several development trends have paved the way toward this new kind of cardiac stent, for which technology is aligning with the need for minimally invasive implantation techniques for decellularized tissue-engineered heart valves (DTEHV), according to a Dutch study team.

The proof-of-concept study from Eindhoven University of Technology in the Netherlands describes the design and manufacture of a polymer stent with mechanical performance properties similar to that of conventional nitinol stents that have been used for heart valve implantation in animal trials.

A 3D printed biodegradable stent for tissue-engineered heart valves, republished with permission of 3D Printing and Additive Manufacturing. Photo by Dr. B. Sanders and Dr. M.S. Cabrera, Eindhoven University of Technology.

The investigators created the computer-designed stents from a commercially available 3D polymer, conducted crush and crimping tests to validate the results predicted by the computational model, and used accelerated hydrolysis to assess degradability in the human body.

Computational-based 3D printed self-expandable and biodegradable polymer stents can be successfully designed, concluded Drs. María Sol Cabrera, Bart Sanders, and colleagues at Eindhoven.

"By adopting 3D printing as a manufacturing method, we were able to evaluate the crimpability and self-expandability of our stent designs in the lab just a few minutes after completing our simulations," Cabrera wrote in an email. "This allowed us to demonstrate that with a rational computational design, bioabsorbable polymers can be applied to produce strong stents that can ultimately replace the use of metals stents in pediatrics."

About 280,000 patients undergo heart-valve surgery every year, growing annually to an expected 1 million by 2050, the authors wrote. New DTEHV developments are promising in their capacity to remodel, based on sheep studies, which revealed rapid host cell repopulation and extracellular matrix production, two indicators of stent growth potential. Advances in valve development go hand in hand with the need for minimally invasive stent implantation, the team wrote 3D Printing and Additive Manufacturing March 2017, Vol. 4:1, pp. 19-29).

Limitations of current metal stent technology include a lack of growth capacity, which can lead to long-term complications such as hyperplasia. And bioabsorbable 3D printed stents would enable clinicians to avoid another round of surgery to remove the implants after the new valve has integrated itself into the heart tissue.

Unfinished work

The new polymer stent still lacks a key feature, however. If DTEHVs are to be used in children, they must be able to accommodate growth, which will require the development of new printing materials.

"The premise behind this opportunity is to eliminate the need for redo surgeries, to further expand the metal stent as the patient grows, and replace it with structures that disappear by themselves after doing their job," Cabrera told AuntMinnieEurope.com.

Polymers have several other potential benefits, including a low rate of late thrombus formation, and less interference with MRI than metal stents, according to the authors, who are aiming for equivalent performance to nitinol stents used with valve implantation in sheep.

A nitinol stent was used to design the polymer stent based on fused deposition modeling (FDM) technology combined with a commercially available thermoplastic copolyester elastomer (TPC). The polymer stent was composed of a repeating design with three rings of 40 struts, connected by tilted bridges.

Tensile tests were used to mechanically characterize the TPC and used as input for the computational model. The authors tested FlexiFil (Formfutura), a flexible TPC filament used for FDM applications, and 3D printed dog bone samples from the same material to assess the production procedure.

Design optimization

The optimization procedure is an iterative process that adjusts the polymer stent geometry to 1) allow crimpability of the stent to a diameter of 12 mm, and 2), obtain a [radial force] RF comparable to that of nitinol stents, Cabrera and colleagues explained. Parameters including width, thickness, and number of struts can be adjusted to modify the response of the polymer stent.

Based on the computationally engineered designs, 3D printed stents were created and subjected to crush, crimping, and self-expansion tests for mechanical validation using FE software (ABAQUS 6.14, Dassault Systèmes Simulia).

Low doses can make DSCT cardiac perfusion routine

April 25, 2017 -- The latest generation dual-source CT (DSCT) scanner cuts the radiation dose of cardiac CT perfusion enough to make it suitable for daily practice, according to new research. Expanded z-axis coverage and better signal-to-noise ratios can offer more information on myocardial blood flow.

A Japanese study presented at ECR 2017 compared image quality and radiation dose when going from second-generation DSCT (Somatom Flash, Siemens Healthineers) with a third-generation system (Somatom Force, Siemens). The group from Mie University Hospital in Tsu examined patients with known or suspected coronary artery disease undergoing stress CT perfusion on the second-generation system and then the third-generation DSCT scanner. Comparing contrast-to-noise ratio and radiation dose between the two, the results showed better enhancement combined with radiation dose reductions of about one-third.

Dynamic perfusion CT of a 55-year-old man after coronary artery bypass grafting. Z-axis coverage of 10.5 cm in the third-generation scanner was sufficient to cover the entire left-ventricular myocardium. Left-ventricular atheroma at myocardium reveals similar perfusion on the anterior and inferior walls, but radiation dose was 30% lower (3.0 mSv) at third-generation DSCT. Images courtesy of Dr. Kakuya Kitagawa, PhD.

Dose length product per phase and of the entire exam was about 30% lower with the third-generation system than the second-generation scanner, said Dr. Masafumi Takafuji in his ECR talk.

Alerts to other physicians

Activation of the "expand action" facility does an efficient job of making referring physicians aware of missed reports, the authors said. This facility has proved particularly useful in the case of referring physicians who work part-time, who are retired, or who are on a lengthy vacation. It has also helped when referring physicians were not familiar with the operation of the alert system (e.g., when they only worked at the hospital for a short time).

The alert system can help avoid neglected reports of unexpected significant findings, and it is designed to make information more easily shared, they added. Separate qualitative audits may be useful to evaluate whether the practice is affected by the shared information. At Ofuna Chuo Hospital, currently staff check the contents of the medical record manually, but from now on the automation of qualitative audits and evaluation is under consideration.

"In Japan, it is important to communicate information within the EHR," Aoki and colleagues stated. "Overall clinical care from diagnosis to treatment is completed within one hospital, and the EHR is a common language in the Japanese medical environment."

Appropriate communication is an essential way of ensuring medical safety, and tools like alert systems contribute to good communication, they concluded. Follow-up of noncritical actionable findings is being examined by the Integrating the Healthcare Enterprise (IHE), raising hopes that greater standardization will occur.

PACS alerts can boost communication with referrers

May 10, 2017 -- A fatal accident due to an oversight by a referring physician has prompted staff at a radiology department to implement a PACS alert system, and it's already helping to improve communication and collaboration between radiologists and referring physicians.

The accident occurred at the Ofuna Chuo Hospital in Kamakura, Japan. A chest physician failed to recognize an abdominal aortic aneurysm (AAA) on a follow-up CT scan for lung cancer. The physician paid attention only to lung cancer, neglecting to view other images and the radiologist's report, after which the patient died due to the rupture of the AAA, according to Yousuke Aoki, a technologist in the Department of Radiology and Radiation Oncology Center, and colleagues.

"In our hospital, when radiologists detect unexpected significant and/or urgent findings, they attempt to inform the referring physician by telephone. In this case, however, the referring physician could not be reached, because he was out of hospital," they explained in an e-poster presentation at ECR 2017. "This experience motivated us to develop a system providing alert notices for significant and/or urgent findings to referring physicians."

How the system works

Under the alert system implemented at Ofuna Chuo Hospital, radiologists who detect an urgent finding select the examination from the PACS list view and activate the alert system on the examination, a function the system defines as "expand action." The PACS sends the accession number and the report of the examination to the electronic health record (EHR), which generates an urgent message from the information sent by the PACS. This message is displayed on the referring physician's screen.

If the referring physician does not log on to the EHR, the system activates at the next log on, and while this message is displayed, other functions are locked, and if the referring physician continues to avoid the message, the system issues further warnings at constant intervals. After three business days, the warning is sent to all the doctors in the physician's department.

Between October 2014 and October 2016, 204,957 reports were made at the hospital, Aoki and colleagues reported. Of these, 476 reports had significant and/or urgent unexpected findings and needed activation of the alert system. Reports with activation were confirmed more frequently within three days than those without activation (97.9% versus 9.0%; p < 0.05), and within seven days (100% versus 9.6%; p < 0.05).

"We found the reference point of evaluation, to achieve 100% communication between the radiologist and the referring physician, can be completed in seven days in this system," they noted. "This system can play a role in ensuring communication among medical staff."

They suggest not using the alert system for all reports, however. Using it often would risk making the referring physicians too accustomed to the alerts and lose interest, thereby not aiding communication. Limiting the system to significant and/or urgent findings means it would be used in about 0.2% of cases, and this rare frequency would strengthen the value of the warning, the authors wrote.

Weight Loss Can Slow Down Knee Joint Degeneration

May 2, 2017  OAK BROOK, Ill. — Overweight and obese people who lost a substantial amount of weight over a 48-month period showed significantly lower degeneration of their knee cartilage, according to a new study published online in the journal Radiology.

According to the National Institutes of Health, obesity is a risk factor for osteoarthritis. Being overweight or obese can place extra pressure on joints and cartilage, causing them to wear away. In addition, people with more body fat may have higher blood levels of substances that cause inflammation in the joints, raising the risk for osteoarthritis.
“For this research, we analyzed the differences between groups with and without weight loss,” said the study’s lead author, Alexandra Gersing, M.D., from the Department of Radiology and Biomedical Imaging at the University of California, San Francisco. “We looked at the degeneration of all knee joint structures, such as menisci, articular cartilage and bone marrow.”
The research team investigated the association between weight loss and the progression of cartilage changes on MRI over a 48-month period in 640 overweight and obese patients (minimum body mass index [BMI] 25 kg/m²) who had risk factors for osteoarthritis or MRI evidence of mild to moderate osteoarthritis. Data was collected from the Osteoarthritis Initiative, a nationwide research study focused on the prevention and treatment of knee osteoarthritis. Patients were categorized into three groups: those who lost more than 10 percent of their body weight, those who lost five to 10 percent of their body weight, and a control group whose weight remained stable.
The results showed that patients with 5 percent weight loss had lower rates of cartilage degeneration when compared with stable weight participants. In those with 10 percent weight loss, cartilage degeneration slowed even more.
Not only did the researchers find that weight loss slowed articular cartilage degeneration, they also saw changes in the menisci. Menisci are crescent-shaped fibrocartilage pads that protect and cushion the joint.
“The most exciting finding of our research was that not only did we see slower degeneration in the articular cartilage, we saw that the menisci degenerated a lot slower in overweight and obese individuals who lost more than 5 percent of their body weight, and that the effects were strongest in overweight individuals and in individuals with substantial weight loss,” Dr. Gersing said.
Light to moderate exercise is also recommended to protect against cartilage degeneration in the knee.
“Our study emphasizes the importance of individualized therapy strategies and lifestyle interventions in order to prevent structural knee joint degeneration as early as possible in obese and overweight patients at risk for osteoarthritis or with symptomatic osteoarthritis,” Dr. Gersing said.

The good news is that intensive international research, including work by German radiological bodies, has significantly improved the situation for pacemaker and ICD patients over recent years: people with conventional pacemakers or ICDs can now be examined using "off-label" procedures, subject to certain safety precautions. And we now have MRI-safe pacemakers and ICDs that are certified and authorized for use under specific conditions.

That sounds like a positive development. But what's the catch?

The problem is that it is still very difficult for most pacemaker and ICD patients to get an MRI scan -- even for those fitted with the new devices that are conditionally MRI-safe. This is partly because referrers, cardiologists, and radiologists don't know enough about this new and complex subject, and also because no clear procedures and responsibilities have been defined for radiologists and cardiologists working together.

We do have publications by individual associations: the 2013 European Society for Cardiology (ESC) guidelines and the DRG's 2015 position paper. Where does the DGK and DRG consensus paper fit in?

I have great respect for cardiology guidelines. However, the relevant chapter of the ESC publication deals with the whole subject in just two pages of highly simplified recommendations that don't reflect the complexity of the issue. For example, it leaves out key safety aspects such as pulse oximetry monitoring of patients, and nearly all the controllable risk management aspects of MRI technology. These include the ability to reduce high-frequency energy input by modifying MRI sequence parameters.

And what was the purpose of the DRG's 2015 paper?

The DRG's 2015 position paper was a response to the ESC publication and provided a detailed description of the radiology and physics of MRI in pacemaker patients. It reinforced, expanded, and in some cases, corrected, the ESC paper.

The new DGK and DRG consensus paper is the logical next step after these publications, setting out the two associations' objectives and ratified by both bodies. It clearly defines the interfaces between radiology and cardiology, provides harmonized and jointly ratified risk assessment and patient monitoring procedures, and presents specific reprogramming options for pacemaker and ICD systems that have been optimized for patient safety and clinical practicability.

What was it like working with your cardiology colleagues?

There were some tensions and political turf wars at first, and we exchanged a few strongly worded emails. But later on, as we discussed the issues involved and shared our specialist expertise in cardiology, electrophysiology, MRI physics, and radiology, we developed a very good, fruitful, and professional relationship.

As the authors, we're delighted the consensus paper has been brought to a successful conclusion. It's taken two years of work and five approval bodies, but there has been no significant friction or editing cuts!

March 10, 2017 -- In a stunning development, a European Union regulatory body on March 10 recommended that four gadolinium-based contrast agents (GBCAs) for MRI scans be pulled off the market due to concerns about gadolinium remaining in the body years after scans occur. The agents affected include some of the most widely used contrast products in medical imaging.

April 4, 2017 -- The German Cardiology Society (DGK) and the German Radiological Society (DRG) have published a joint consensus paper on carrying out MRI examinations on patients with pacemakers and implantable cardioverter defibrillators (ICDs). In this interview, lead author Dr. Torsten Sommer, head of the Diagnostic and Interventional Radiology Department at the German Red Cross Hospital in Neuwied, Germany, explains the aim of this initiative and why it can improve MRI access for this patient group.