Posts Tagged ‘Positron Emission Tomography’


FDA Recalls GE’s Infinia Hawkeye 4 Nuclear Medicine System used in Nuclear Medicine Imaging for Detection of Radioisotope Tracer Uptake in the Patient’s body

Reporter: Aviva Lev-Ari, PhD, RN

Hospital Death Forces Recall of GE Healthcare‘s Nuclear Medicine Machines

7/30/2013 7:36:26 AM

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Hospital patients face delays after 120 nuclear medicine machines were recalled across Australia following the death of a patient in the US. Authorities ordered hospitals across Australia to stop using the nuclear medicine imaging systems, preventing patients from being scanned while the machines are checked for safety. A 66-year-old patient being scanned in a veterans’ hospital in New York was crushed when a GE Healthcare Infinita Hawkeye 4 system collapsed when bolts securing the machine came loose.



Hospital death forces recall of nuclear medicine machines across Australia

HOSPITAL patients face delays after 120 nuclear medicine machines were recalled across Australia following the death of a patient in the US.

Authorities ordered hospitals across Australia to stop using the nuclear medicine imaging systems, preventing patients from being scanned while the machines are checked for safety.

A 66-year-old patient being scanned in a veterans’ hospital in New York was crushed when a GE Healthcare Infinita Hawkeye 4 system collapsed when bolts securing the machine came loose.

The recall notice was sent to Australian hospitals including the Women’s and Children’s Hospital more than a month later on July 9.

Six of 91 systems in Australian centres checked so far require repair to prevent a similar collapse, according to federal health officials, with 29 still to be checked.

Ten were operating in South Australian hospitals including two at the Royal Adelaide Hospital and one each at the Women’s and Children’s, the Queen Elizabeth Hospital and Lyell McEwin Hospital, with the others in private clinics.

GE Healthcare inspectors have inspected seven of these so far and not found any problems,.

SA Health, however, so far has only released one at the RAH and one at the QEH for use.

It released a statement to The Advertiser saying it had “a fleet of gamma cameras across South Australian public hospitals.”

“Five were identified as being in scope of the review,” the statement says. “Use of these five cameras was suspended immediately and GE is currently in the process of reviewing the machines. Two cameras have already been cleared and have resumed scanning.

“SA Health is working with GE Healthcare to minimise the impact on patients during this review.

“However some patient appointments have required rescheduling or rebooking on a different camera. There have been no incidents involving SA Health cameras.”

The systems, estimated to be worth from $300,000 to $800,000 depending on the model, track radiation emitted by radioactive fluids injected into patients to build images of organs and deep tissue to diagnose a range of diseases.

Information generated can pinpoint diseases before anatomical changes in organs and has some advantages over some other scanning techniques such as MRI and CAT scans.

Patients lie on their back with lead encased panels housing gamma cameras above and around them to track the radiation, and the entire machine can weigh in excess of 2000kg.

No deaths or injuries related to the safety issue have been reported in Australia.

The Therapeutic Goods Administration released a statement over the recall, advising patients to speak to their health professional if they have concerns.

“Due to the prevalence of affected nuclear medicine imaging systems in Australia and the need to have such systems inspected regarding this issue before use, there may be delays in accessing some diagnostic scan services,” the statement says.

In its letter to hospital officials GE Healthcare chief medical office Dr Douglas Hansell says: “Please be assured that maintaining a high level of safety and quality is our highest priority.’



GE Healthcare Nuclear Medicine Systems

Recall Class:  Class I

Date Recall Initiated: June 13, 2013

Products: Infinia Nuclear Medicine Systems, VG and VG Hawkeye Nuclear Medicine Systems, Helix Nuclear Medicine Systems, Brivo NM615, Discovery NM630, Optima NM/CT640, Discovery NM/CT670

Models: Infinia 3/8, Infinia-II 3/8, Infinia VC, Infinia II VC, Infinia 3/8 Hawkeye, Infinia VC Hawkeye, Infinia II 3/8 Hawkeye, Infinia II VC Hawkeye, Infinia II 3/8 HE4, Infinia II 5/8 HE4, Infinia II VC HE4, Varicam, Millennium VG 3/8, Millennium VG 5/8, Millennium VG 3/8 Hawkeye, Millennium VG 5/8 Hawkeye, Discovery VH, Helix nuclear medicine systems, Brivo NM615, Discovery NM630, Optima NM/CT640, Discovery NM/CT670

These affected products were distributed from October, 1992 through June, 2013.

Use:  These Nuclear Medicine systems are used to perform general Nuclear Medicine imaging procedures for detection of radioisotope tracer uptake in the patient’s body, using a variety of scanning modes supported by various acquisition types and optional imaging features designed to enhance image quality in Oncology, Cardiology, Neurology and other clinical diagnostic imaging applications. The scanning modes include planar (Static, Multi-gated, Dynamic, Whole body scanning) and tomographic (SPECT, Gated SPECT, Whole body SPECT, Camera based PET – also known as Coincidence Detection). Acquisition types include single and multi-isotope/multi-peak frame/list mode single-photon and positron imaging. Optional imaging-enhancement features include assortment of collimators, gating by physiological signals, real-time automatic body contouring, and CT-based attenuation correction and functional anatomic mapping.

Recalling Firm: 
GE Healthcare, LLC
3000 N Grandview Blvd.
Waukesha WI 53188-1615

GE Medical System Israel Ltd
4 Hayozma St.
Tirat Hacarmel, Israel

Reason for Recall: GE Healthcare became aware of an incident at a VA Medical Center facility in the US. A patient died due to injuries sustained while being scanned on an Infinia Hawkeye 4 Nuclear Medicine System. On July 03, 2013 GE notified hospitals that they were recalling several Nuclear Medicine Imaging Systems because serious injuries or deaths could occur due to the failure mode associated with this recall. GE advised hospitals that they cease use of their Nuclear Medicine systems until GE can complete an inspection of the system. In the second notification, GE included all Nuclear Medicine Systems.

Public Contact: For questions about this recall contact GE Healthcare Service Representative at 1-800-437-1171

FDA District: Minneapolis District Office

FDA Comments:

On June 17, 2013 GE sent an Urgent Medical Device Correction letter to all affected customers. The letter identified the affected product, recommended that qualified service personnel maintain the equipment and that Preventative Maintenance procedures were executed according to labeling. In addition, the Safety Chapter Sections should be re-reviewed with personnel to ensure proper operation of the equipment.

On July 03, 2013 GE notified customers again via an Urgent Medical Device Recall letter (including confirmation of delivery for US customers) and follow-up telephone calls. Healthcare facilities are instructed to cease use of their Nuclear Medicine system until a GE Healthcare Field Engineer is able to do a complete inspection of the system and perform any necessary repairs at no cost. A GE Healthcare representative will contact the hospitals to arrange for the inspection.

Physicians: No action is required beyond the recommendations provided in the Urgent Medical Device Recall letter.

Health care professionals and consumers may report adverse reactions or quality problems they experienced using these products to MedWatch: The FDA Safety Information and Adverse Event Reporting Program either online, by regular mail or by FAX.

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Larry H Bernstein, MD, …   received

http://No dishonour in depression/2013/06/23

Nature | Editorial

No dishonour in depression

The stigma associated with mental illness discourages investment in finding cures — even though the burden of the disorders on society is immense.

Comedian and writer Ruby Wax, a regular on British television, has clinical depression. In her book published last week, Sane New World (Hodder & Stoughton, 2013), she describes her struggles with different therapies and her fear of being ‘found out’. She is not alone. A 2010 survey in Europe revealed that 38% of people had a diagnosed mental disorder — including 7% with major depression. The proportion is likely to be similar in all populations, even in Africa, where psychiatric disease barely features on the health agenda.

The stigma attached to such disorders means that many people do not admit to their illness. The same stigma discourages investment, so that research funding is not proportional to the distress these disorders cause. Why lobby for better treatments for depression or schizophrenia when there are ‘real’ diseases out there, such as cancer?

Wax has been through the catalogue of available therapies and says that she has settled on an approach known as ‘mindfulness’, which helps to keep her depression under control. It may seem that the various therapies are inadequate, given that initial treatment of depression fails in 60% or more of cases. It is true that more treatment options are badly needed. Yet evidence-based cognitive behavioural therapies and drugs already developed by the pharmaceutical industry can work splendidly for long periods — if they are given to the right patients.

How do you recognize the right patients? Treatment decisions tend to be based on the preferences of physicians or their patients, often with a missionary zeal that gives no credence to the idea that a personalized approach would be more appropriate. Some hold that drugs have unacceptable side effects, whereas others say that cognitive therapy wastes time if the depressed brain is not first chemically lifted. It is becoming increasingly common to offer patients both treatments at once in the belief that drugs can prepare the brain to respond to cognitive therapy. That may be so, but it is also possible that the improved response rates are simply the result of catching two different populations.

The situation would improve drastically if simple tests could be developed to predict treatment outcome. Many exploratory clinical trials are now under way to search for biomarkers in genes or in the brain itself that might be predictive. This week sees the description of the first potential biomarker for discriminating between responders and non-responders to drugs or cognitive therapy in major depressive disorder (C. L. McGrath et al. JAMA Psychiatry http://dx.doi.org/10.1001/jamapsychiatry.2013.143; 2013).

“The stigma attached to mental disorders will fade when treatment becomes more effective.”

The study, led by neurologist Helen Mayberg of Emory University in Atlanta, Georgia, used positron emission tomography (PET) scans to measure metabolic activity in various brain regions of people with untreated depression (see also Nature http://doi.org/mtc; 2013). Patients were randomized into groups and treated for 12 weeks with either a commonly used antidepressant drug or cognitive behaviour therapy. The study’s results were clear-cut. Below-average activity in a brain area called the right anterior insula — which is linked with depression-relevant behaviours such as emotional self-awareness and decision-making — was associated with the patient showing a good response to cognitive behavioural therapy and a poor response to the drug. Above-average insula activity was predictive of the opposite.

This potential biomarker must still be tested in prospective clinical trials, which will assign patients to a treatment on the basis of their insula activity. It may fail. But if the biomarker comes up trumps, it could be transformative for many patients who would not have to endure two or three months of treatment trial and error.

If attitudes to mental illness do not change, even a successful biomarker of this type will have a hard time being accepted by health systems that foot the bills. Unlike a simple blood test, a PET scan is inconvenient because not all physicians have easy access to the technology and, at up to US$2,000 a shot, the procedure is not cheap. Although expensive treatments for other diseases and arguments about how to fund them are nothing new, this rational debate is harder for mental illnesses because of the irrational stigma that is attached to them.

Fifty years ago, the stigma surrounding cancer meant that physicians would sometimes lie to patients about the diagnosis from kindness. That has now faded because cancer is not always the death sentence it once was — thanks in part to the development of biomarkers that guide therapy. The stigma attached to mental disorders will also fade when treatment becomes more effective. But to break out of a vicious circle of underinvestment in a stigmatized disease area will require continued effort to get the problem recognized. This is a good week for that.

Journal name:
Date published:
(13 June 2013)


PET at NIH Clinical Center. General Electric (...

PET at NIH Clinical Center. General Electric (GE) Advance positron emission tomography (PET) scanner. (Photo credit: Wikipedia)

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Acute and Chronic Myocardial Infarction: Quantification of Myocardial Perfusion Viability – FDG-PET/MRI vs. MRI or PET alone

Author, and Content Consultant to e-SERIES A: Cardiovascular Diseases: Justin Pearlman, MD, PhD, FACC


Reporter: Aviva Lev-Ari, PhD, RN

The Voice of  Justin Pearlman, MD, PhD, FACC

While working on angiogenesis imaging support at Harvard, the author discovered that injured heart muscle retains gadolinium-based contrast used for perfusion testing (1992). Whereas the gadolinium passes through normal tissue in less than 20 minutes and redistributes mostly to body fat, it stays where cell membranes are damaged, even if the damage is old. The gadolinium then “lights up” the damaged zone when normal heart muscle tissues appear dark by magnetic resonance imaging (MRI). Thus “scar mapping” was born. Prior to that discovery, the standard test for “viability” was a positron emission tomography (PET) scan reporting the presents of absence of normal sugar metabolism in damaged or ischemic heart muscle. PET relies on detection of a pair of gamma rays emitted by a radioactive label in a metabolite. The pair are emitted simultaneously at nearly 180 degrees apart, with a small angulation offset from the momentum of the emitter. The emission event requires a positron finds an electron, so it does not occur precisely where the metabolite sits, and thus has inherently a poor “resolution” (minimal distance where two distinct sources are identifiable as distinct).  The protocol for PET assessment of heart muscle viability utilized by the author and other investigators required intravenous infusion of glucose, insulin, and potassium, to assure good delivery of sugar to the healthy viable heart muscle, coupled to repeat blood tests to make sure the blood sugar and serum potassium levels were adequately maintained (otherwise the patient could suffer from low sugar or a potassium-related arrhythmia). Numerous investigatores followed up on this discovery, and determined that a gadolinium demarcated defect less than half the heart wall thickness corresponded clinically to viable myocardium (meaning one could expect improved function after revascularization of a blocked blood supply) whereas a defect more than half the wall thickness corresponded clinically to non-viable myocardium (no expected significant functional gain from revascularizing that region). Subsequently, a third option for assessment of viability was developed: combined PET and MRI.

PET/MRI device produced “high-quality cardiac MR imaging acquisitions,” overcoming any technical issues of having the PET detector within the MRI’s 3-tesla magnet field, Nensa and colleagues concluded.

“No negative side effects from the integrated imaging system design were observed,” they noted.

The researchers were able to show “a close match” between FDG-PET and MRI in assessing myocardial viability and infarct quantification among patients with acute and chronic myocardial infarction.

“These findings demonstrate the feasibility of clinical cardiac MR imaging with an integrated PET/MRI device,” they added. “However, to prove that the integrated design does not interfere with the performance of the device, a systematic intraindividual comparison with a comparable 3-tesla MRI system and identical sequence parameters is still needed.”

Future studies should investigate whether hybrid FDG-PET/MRI of myocardial infarction can provide additional information compared with MRI or PET alone, according to the authors.


Study shows feasibility of cardiac PET/MRI — with caveats

By Wayne Forrest, AuntMinnie.com staff writer
May 9, 2013

Cardiac FDG-PET/MRI is feasible on an integrated whole-body PET/MRI system, but the hybrid modality still must prove it adds clinical relevance to cases of ischemic heart disease, according to a study published online May 7 in Radiology.

The study from University Hospital Essen in Germany found good concordance with the simultaneous acquisition of FDG-PET and MR images regarding both cine and late gadolinium-enhanced imaging in patients with myocardial infarction.

However, despite the simultaneous MRI and PET acquisition, “consolidated cardiac PET/MRI protocols need to be established, as long examination times associated with fasting seem to compromise patient compliance” with the exams, wrote lead author Dr. Felix Nensa, from the department of diagnostic and interventional radiology and neuroradiology, and colleaguesRadiology, May 7, 2013).

Cardiac feasibility study

The purpose of the study was to determine the feasibility of simultaneous acquisition of cardiac images on an integrated 3-tesla PET/MRI system, and to determine if the placement of the PET detector within the MRI’s field of magnet strength would adversely affect clinical results.

The researchers evaluated 20 consecutive patients with ischemic heart disease who were referred for FDG-PET/MRI between May and December 2012. Among the 20 patients, 14 had confirmed acute ST-elevation myocardial infarction within four to 15 days after interventional revascularization, one had suspected non-ST-elevation myocardial infarction, and five had chronic myocardial infarction.

Ten of the 20 patients underwent additional cardiac PET/CT before their PET/MRI scan.

Individuals with contraindications for gadolinium-based contrast agents and general MRI conditions, such as claustrophobia, were excluded from the study. All patients were asked to detail any personal discomfort or side effects that occurred during the PET/MRI exam.

All imaging studies were performed with an integrated whole-body PET/MRI system with 3-tesla field strength (Biograph mMR, Siemens Healthcare) and the PET insert inside the MRI scanner. All MRI sequences were performed with phased-array body surface coils designed for the PET/MRI system.

For late gadolinium-enhanced qualitative imaging, patients received gadobutrol (GadovistBayer HealthCare Pharmaceuticals) based on a dosage of 0.2 mmol/kg of body weight.

FDG-PET/MRI studies were performed after a fasting period of at least six hours, with FDG administered one hour before imaging with a mean of 202 (± 21) MBq. The scans began at a mean of 129 (± 41) minutes after FDG injection and included an electrocardiographically gated cardiac PET scan with one bed position and 3D image reconstruction.

For the FDG-PET/CT scans, an electrocardiographically gated cardiac PET/CT study was performed with a 128-slice CT unit (Biograph mCT, Siemens). PET scans began approximately 70 (± 12) minutes after FDG injection, with a mean of 211 (± 55) MBq.

Image comparisons

To compare the identification and characteristics of the infarcts between the two hybrid modalities, the researchers mapped the left ventricle with a 17-segment model, as recommended by the American Heart Association. Two-point scoring systems were used to assess myocardial tracer uptake, myocardial wall motion, and myocardial late enhancement in each segment.

In addition, the researchers measured the size of a patient’s infarct zone by drawing regions on the late gadolinium-enhanced MR images and PET images, and it was expressed as a percentage of the entire left ventricular myocardium.

Nensa and colleagues were able to complete 19 of 20 cardiac PET/MRI scans. One patient with ST-elevation myocardial infarction did not finish due to claustrophobia. Total PET/MRI scan time without patient preparation and positioning was 53 (± 3) minutes, and all cardiac MR images were rated as diagnostic in quality.

The analysis of FDG-PET and MRI with the 17-segment model found “good concordance” of the left ventricle with both cine imaging and late gadolinium-enhanced imaging in 18 of the 19 patients.

Of the 306 segments evaluated, 97 (32%) were rated as infarcted on PET images, compared with 93 (30%) rated as infarcted on late gadolinium-enhanced images and 90 (29%) on cine images.

Two-chamber views show “stunned myocardium” in a 66-year-old patient with ST-elevation myocardial infarction and acute occlusion of the left anterior descending artery. Cardiac PET/MRI was performed seven days after intervention. Late gadolinium-enhanced image (top left) shows no infarction zone. Fused late gadolinium-enhanced and PET images (top right) show that tracer uptake was reduced in segments 13-15 and 17. T2-weighted MR image (bottom left) shows myocardial edema (arrows) that corresponded well with the area of reduced tracer uptake on the bottom right image. All images courtesy of Radiology.

The size of the infarct zones averaged 22% of the entire left ventricular myocardium on PET images, compared with an average of 20% on late gadolinium-enhanced images.

Among the subgroup of 10 patients with an additional PET/CT scan, no significant difference in myocardial tracer uptake between PET/CT and PET/MR images was found.

In patient exit interviews, 16 patients cited long examination times (including patient preparation) as a source of discomfort. In addition, 11 patients cited the PET/MRI exam itself, i.e., noise, narrowness, and immobility, while 15 patients did not like having to fast.

Final conclusions

In summary, the PET/MRI device produced “high-quality cardiac MR imaging acquisitions,” overcoming any technical issues of having the PET detector within the MRI’s 3-tesla magnet field, Nensa and colleagues concluded.

“No negative side effects from the integrated imaging system design were observed,” they noted.

The researchers were able to show “a close match” between FDG-PET and MRI in assessing myocardial viability and infarct quantification among patients with acute and chronic myocardial infarction.

“These findings demonstrate the feasibility of clinical cardiac MR imaging with an integrated PET/MRI device,” they added. “However, to prove that the integrated design does not interfere with the performance of the device, a systematic intraindividual comparison with a comparable 3-tesla MRI system and identical sequence parameters is still needed.”

Future studies should investigate whether hybrid FDG-PET/MRI of myocardial infarction can provide additional information compared with MRI or PET alone, according to the authors.

Related Reading

MRI motion correction improves PET/MR image quality, July 6, 2012

SNM: PET/MRI for myocardial perfusion feasible but challenging, June 11, 2012

SNM: Hybrid PET/MRI study among top 5 research papers, June 7, 2011

Copyright © 2013 AuntMinnie.com



SNM: Hybrid PET/MRI study among top 5 research papers

By Wayne Forrest, AuntMinnie.com staff writer

June 7, 2011 — SAN ANTONIO – The first-ever study on the clinical use of PET/MRI and a breakthrough on the use of FDG-PET to detect fevers of unknown origin were among the top research papers outlined Monday at this week’s Society of Nuclear Medicine (SNM) annual meeting.

More than 1,000 papers were submitted for consideration and presentation at this year’s meeting, with many studies showing how molecular imaging is gaining influence in the early detection of Alzheimer’s disease. Other submissions included a first-of-its-kind study on the use of near-infrared fluorescence and a new synthesized imaging agent to discover hidden blood clots in veins and arteries.

Hybrid PET/MRI

Early results from the clinical use of PET/MRI indicate that the hybrid modality can provide important diagnostic information about soft tissues and physiological functions throughout a patient’s body. The technology’s ability to find suspicious lesions and potential cancer already appears comparable to that of conventional molecular imaging methods.

In a German study, 11 patients with cancer underwent single-injection PET/CT followed by PET/MRI (Biograph mMR, Siemens Healthcare). Simultaneous PET/MRI acquisition was feasible and offered good-quality PET and MRI diagnostic data.

The analysis found that all 13 lesions detected at PET/CT were also identified by PET/MRI, with no significant difference between PET/CT and PET/MRI regarding the uptake ratios.

The study “demonstrates for the first time that newly introduced integrated whole-body MR/PET technology allows simultaneous acquisition of high-quality MR and PET data in a clinical setting within an acceptable time frame,” wrote lead study author Dr. Alexander Drzezga from TU München.

The hybrid technology could result in the development of new imaging agents that combine the diagnostic prowess of PET and MRI, Drzezga said. With the ability to image physiologic and pathophysiologic processes at the same time, the technology could open a new imaging discipline within nuclear medicine.

Carcinoma is compared in a patient who received a PET/CT scan 80 minutes after contrast injection (above), followed by a PET/MRI scan 160 minutes after contrast injection (below). All images courtesy of SNM.

FDG-PET and fever of unknown origin

Japanese researchers broke new ground in their study, which concluded that FDG-PET provided additional diagnostic information in cases of fever of unknown origin. The use of FDG-PET also had a high clinical impact, especially among patients with infectious diseases.

The retrospective study evaluated 81 consecutive patients with fever of unknown origin. They underwent FDG-PET at six Japanese institutions between July 2006 and December 2007.

Results were divided into four groups for final diagnoses: infection, arthritis/vasculitis/autoimmune/collagen disease, tumor/granuloma, and other/unknown.

The analysis found that sensitivity was highest in the tumor/granuloma group at 100% (seven of seven cases), followed by infection at 89% (24 of 27 cases) and arthritis/vasculitis/autoimmune/collagen disease at 65% (11 of 17 cases). Sensitivity was 0% (zero of one case) in the other/unknown category. Overall sensitivity was 81% and overall specificity was 75%.

Additional information provided by FDG-PET was highest in the infection group, at 76% of the cases (22 of 29), followed by tumor/granuloma at 75% (six of eight), arthritis/vasculitis/autoimmune/collagen disease at 43% (nine of 21), and other/unknown at 23% (five of 22).

The other/unknown group showed a high specificity of 84% (16 of 19 cases) and accurately excluded active focal inflammatory diseases and malignancy.

Lead study author Dr. Kozuo Kubota, PhD, chief of nuclear medicine at the National Center for Global Health and Medicine in Tokyo, said that until now, conventional modalities have produced low imaging resolution and very poor detectability for the fever’s cause.

“If the CT scan, ultrasound, or other conventional imaging technique fails, it is very difficult to find ways to find the focus of the fever,” Kubota said. “If we use FDG-PET, we can scan from head to thigh in only one scan to detect where the truly active lesion is. FDG is very sensitive both for inflammation and the tumor.”

With the addition of FDG-PET, physicians discovered a graft infection in a 50-year-old male with kidney failure and fever of unknown origin, with high FDG uptake illustrating the malady.

“I view this [study] as extraordinary,” said Dr. Michael Graham, PhD, director of nuclear medicine at the University of Iowa, who announced the top five papers. “This is in a setting where modern medicine is unable to come up with the answer, even after weeks. In about an hour-and-a-half, an FDG-PET scan came up with the answer with excellent sensitivity. We don’t get it every single time, but if it weren’t done, it would be mysterious what the patient had. It would be treated with antibiotics and hope for the best.”

“This is a huge step forward and I think it will change how we approach this problem,” he said.

PET and Alzheimer’s detection

Three studies presented at SNM 2011 added to the growing evidence that PET is an effective method to detect Alzheimer’s disease in its early stages, and that it provides a pathway to future clinical screening and treatments.

One lead study author, Dr. Kevin Ong, research scientist at Austin Hospital in Heidelberg, Australia, said that amyloid imaging with PET scans can help ascertain the likelihood that individuals will deteriorate cognitively within a few years, enabling more efficient channeling of healthcare resources.

Molecular imaging of Alzheimer’s disease has focused on detecting and analyzing the formation of the protein beta amyloid in the brain, which researchers say is directly involved in the pathology of Alzheimer’s. The presence of significant amyloid buildup is also linked to more rapid memory decline and brain atrophy.

Increased amyloid is bad for cognition even in the healthy elderly, noted lead study author Michael Devous Sr., PhD, director of neuroimaging for the Alzheimer’s Disease Center at the University of Texas Southwestern Medical Center.

The three ongoing studies involve several years of research based on hundreds of participants ranging widely in age, cognitive ability, and stage of disease.

Collective results showed that amyloid plaques build up at an estimated rate of 2% to 3% per year, and they often are already present in healthy older individuals. Amyloid plaque was present in 12% of people in their 60s, 30% of those in their 70s, and 55% of those older than 80.

In one study, approximately 25% of subjects older than 60 had amyloid plaques.

For individuals who have already developed a measurable memory decline, a positive scan for amyloid is the most accurate predictor of progression to Alzheimer’s disease, said Dr. Christopher Rowe, a lead investigator for the Australian Imaging, Biomarkers, and Lifestyle study of aging and professor of nuclear medicine at Austin Hospital.

Amyloid imaging with PET scans, he added, will be an important new tool in the assessment of cognitive decline.

Several studies have used carbon-11-labeled Pittsburgh Compound B (C-11 PIB), a PET imaging agent that binds to beta amyloid in brain tissue, but two of the current studies are assessing the benefit of F-18 florbetaben and F-18 florbetapir, which are designed for routine clinical use.

Both F-18 florbetaben and F-18 florbetapir are showing promise as reliable predictors of progression to Alzheimer’s disease, and F-18 amyloid imaging agents are considered most likely to move into clinical practice in the near future, perhaps as soon as next year.

NIRF for blood clot detection

In another novel study at SNM 2011, researchers from Massachusetts General Hospital are using near-infrared fluorescence (NIRF) and a new synthesized imaging agent to detect blood clots inside elusive veins, often within the deep tissues of the thighs and pelvis.

The agent uses a biomarker that seeks out a peptide — called fibrin — that is actively involved in the formation of blood clots. Combined with NIRF, which uses light energy to gather information from cells and tissues, the technique could also be used for coronary arteries. The fibrin peptide agent (EP-2104R) has already been tested in phase II clinical trials.

Lead study author Dr. Tetsuya Hara, PhD, noted that the availability of a high-resolution fibrin sensor is important for two reasons: intravascular NIRF imaging of coronary-sized arteries is now possible, and coupling the fibrin peptide with this technique may allow researchers to study coronary artery plaques and stents, which could potentially help identify patients at increased risk of heart attack.

The researchers were able to successfully detect fibrin-rich deep vein thrombosis with both intravital fluorescence microscopy and noninvasive fluorescence molecular tomography, allowing information to be acquired about tissues by analyzing how light is absorbed and scattered.

By coupling the fibrin peptide agent with intravascular NIRF imaging, researchers can now study microthrombi on coronary artery plaques and coronary stents that are at high risk for thrombosis and vessel occlusion.

This advance could help clinicians predict potential heart attacks and other major cardiovascular events, potentially saving more patients’ lives.

Related Reading

SNM exceeds fundraising goal, June 6, 2011

SNM: PET/MRI must prove its worth to ensure clinical adoption, June 6, 2011

PET/CT with NaF bone agent takes SNM’s Image of the Year, June 6, 2011

SNM proposes name change, May 3, 2011

SNM’s Clinical Trials Network: Progress despite growing pains, April 29, 2011



Copyright © 2011 AuntMinnie.com

Other related articles published on this Open Access Online Scientific Journal, Include the following:

Sudden Cardiac Death invisible at Autopsy: Forensic Power of Postmortem MRI

Aviva Lev-Ari, PhD, RN 4/18/2013


Hypervascular Hepatocellular Carcinoma: Important clues from Gadoxetic acid-based MRI imaging

Ritu Saxena, PhD 4/10/2013


Nanotechnology and MRI imaging

Tilda Barliya PhD 10/17/2012


MRI Cortical Thickness Biomarker Predicts AD-like CSF and Cognitive Decline in Normal Adults

Aviva Lev-Ari, PhD, RN 7/18/2012


Early Detection of Prostate Cancer: American Urological Association (AUA) Guideline

Dror Nir, PhD 5/21/2013


 Whole-body imaging as cancer screening tool; answering an unmet clinical need?

Dror Nir, PhD 1/3/2013


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Reporter: Prabodh Kandala, PhD

The U.S. Food and Drug Administration today approved the production and use of Choline C 11 Injection, a Positron Emission Tomography (PET) imaging agent used to help detect recurrent prostate cancer.

Choline C 11 Injection is administered intravenously to produce an image that helps to locate specific body sites for follow-up tissue sampling and testing in men with recurrent prostate cancer.

PET imaging with Choline C 11 Injection is performed in patients whose blood prostate specific antigen (PSA) levels are increasing after earlier treatment for prostate cancer. An elevated PSA result suggests that prostate cancer may have returned, even though conventional imaging tests, such as computerized tomography (CT), have not shown any signs of cancer. PET imaging is not a replacement for tissue sampling and testing.

Choline C 11 Injection must be produced in a specialized facility and administered to patients shortly after its production. While PET imaging with Choline C 11 Injection has been performed at a few facilities over the past several years, none of these facilities were approved by the FDA to manufacture the agent. The Food and Drug Administration Modernization Act directed the agency to establish appropriate approval procedures and current good manufacturing practice requirements for all PET products marketed and used in the United States. The Mayo Clinic is now the first FDA-approved facility to produce Choline C 11 Injection.

“Choline C 11 Injection provides an important imaging method to help detect the location of prostate cancer in patients whose blood tests suggest recurrent cancer when other imaging tests are negative,” said Charles Ganley, M.D., director of the Office of Drug Evaluation IV in FDA’s Center for Drug Evaluation and Research. “The FDA’s approval of Choline C 11 Injection at the Mayo Clinic provides assurance to patients and health care professionals they are using a product that is safe, effective, and produced according to current good manufacturing practices.”

The safety and effectiveness of Choline C 11 Injection were verified by a systematic review of published study reports. Four independent studies examined a total of 98 patients with elevated blood PSA levels but no sign of recurrent prostate cancer on conventional imaging. After PET imaging with Choline C 11, the patients underwent tissue sampling of the abnormalities detected on the PET scans.

In each of the four studies, at least half the patients who had abnormalities detected on PET scans also had recurrent prostate cancer confirmed by tissue sampling of the abnormal areas. PET scan errors also were reported. Depending on the study, falsely positive PET scans were observed in 15 percent to 47 percent of the patients. These findings underscore the need for confirmatory tissue sampling of abnormalities detected with Choline C 11 Injection PET scans.

Aside from an uncommon, mild skin reaction at the injection site, no side effects to Choline C 11 Injection were reported.

Choline C 11 Injection is manufactured and distributed by the Mayo Clinic PET Radiochemistry Facility in Rochester, Minn

Ref: http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm319201.htm


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