MR/PET: current status in clinical routine and market

Description of technology

Positron Emission Tomography combined with Magnetic Resonance Imaging (PET-MRI) is an emerging technology recently proposed to be used in oncology, neurology and cardiology for diagnostic purposes. The market offers three different PET-MRI systems, developed by three manufacturers (GE, Philips and Siemens). The GE system - "Trimodality PET-CT + MR" – is able to capture and correlate PET, CT and MR images based on two separate devices, a PET-CT and a MRI. The Philips system – “Ingenuity TF” - has PET and MR gantries arranged in the direction of the main scanner axis with a patient handling system mounted between the gantries. Siemens has developed a fully integrated PET-MRI system – Biograph mMR - with simultaneous acquisition with a single gantry. This is the only system capable of simultaneously acquiring the image PET-CT and  MR, instead the other two systems use special software to merge the two types of images. In oncology the expected benefits include the improvement of diagnostic accuracy compared to PET-CT, especially for soft tissue cancers, with a lower radiation exposure.

MR-PET: A new approach in molecular imaging

It is widely accepted that the superimposition of anatomical information improves the predictive value of functional and molecular imaging. This is reflected in the success of hybrid systems using combined PET and CT scanner . But the combination of positron tomography and magnetic resonance imaging can offer great advantages , such as higher contrast with the soft tissue anatomical MRI images with simultaneous exposure to a much lower radiation dose to the patient. Correlative imaging will open up exciting new applications in oncology, neurology and cardiology . At present,  magnetic fields compatibility with PET detectors remains a technical challenge and the restriction of space on the magnet has almost been resolved. There is no fully developed and mature clinical MR / PET system in this market, although this time the three largest manufacturers indicate system availability MR-PET.

Magnetic Resonance Imaging of the Breast

1.  Introduction

Magnetic resonance imaging (MRI) of the breast was first performed in the late 1980s. At first, differentiation between benign and malignant breast lesions was primarily based on their differences in T1 and T2 relaxations times (Rausch et al., 2006). Due to the large overlap in T1 and T2 relaxation times in benign and malignant breast lesions, it became apparent that contrast administration was mandatory for reliable breast MRI. Heywang et al. demonstrated that breast carcinomas showed significant enhancement within 5 minutes after contrast administration (Heywang et al., 1989). 

Since then, increasing field strengths, dedicated breast  coil designs, and improvements in sequence protocols have led to a large improvement in diagnostic accuracy of breast MRI. Currently, the sensitivity of contrast-enhanced MRI for detecting breast cancer reaches 88%, with a specificity of 68%. The positive predictive value is reported to be 72%, with a negative predictive value of 85% (Bluemke et al., 2004). The reported sensitivity and specificity may vary in different publications due to differences in study populations, and technical and diagnostic criteria used. Reported sensitivities therefore vary from 83-100%, with reported specificities varying from 29-100% (Rausch et al., 2006).

New dental MRI study yields best images yet

Dental researchers are making progress in their quest to develop a  practical magnetic resonance imaging (MRI) device that can be used in the operatory for  hard- and soft-tissue analysis and diagnosis.
For the first time ever—and only from Sirona—there's now a complete range of both digital  impressioning systems and single-visit chairside restoration systems to choose from, each  available in a wide range of configurations and price points to fit the framework of any practice and any budget.

SWIFT, a novel MRI technique, can simultaneously image both hard and soft dental tissue. Image courtesy of Djaudat Idiyatullin, Curt Corum, and Steen Moeller (CMRR).

New CT foot scanner at RNOH is transforming diagnosis and treatment

Despite the proliferation of wearable and fashionable health & wellness technologies in recent years, fashion and health are not often a harmonious couple. Most of our readers will be keenly aware of the sacrifices made in the name of sophisticated shoe-wear. High heels, more than any other shoe, are the bane of podiatrists who most deal with the corns, Morton’s neuroma and plantar fasciitis among the numerous conditions which can arise from excessive wear.

Traditionally, 2D X-rays were the tool of choice for podiatrists and orthopedic surgeons assessing foot injury. However, a relatively new product from CurveBeam of Warrington, PA is bringing 3D load-bearing CT scanning to the fight against harmful heels.

CurveBeam’s pedCAT  scanner enables office-based foot and ankle scanning in a load bearing posture. The scan takes just over a minute, and image reconstruction is complete within 2 minutes. The system was approved by the FDA in April 2012 and has made its way to the UK this summer.

Researchers at the Institute of Orthopaedics and Musculo-Skeletal Sciences at University College London in conjunction with the Royal National Orthopaedic Hospital are using the system to treat and manage shoe-related symptoms. The researchers have released a video which includes a wince-inducing CT scan of a foot in high heels. Commentary is provided by Mr Andy Goldberg, a consultant orthopedic surgeon who explains the advantages of the system and highlights the particular injuries that can arise from high heels.

Live from the operating theatre - via Google Glass: First ever live stream of surgery while U.S. doctor uses wearable computer

This is the first ever U.S. live stream of an operation via Google Glass

It showed doctor's vantage point via the internet to audiences miles away

It also allowed the doctor to consult in real-time with a distant colleague

The surgeon used Google Glass to consult with a distant colleague using live, point-of-view video from the operating room.

The live stream was part of the exclusive Google Glass Explorer Program, which invited only 1,000 people in the U.S to test the device. 

A surgeon at The Ohio State University Wexner Medical Center is the first in the United States to consult with a distant colleague using live, point-of-view video from the operating room via Google Glass

GE recalls gamma cameras after fatal accident - Patient at Bronx VA Hospital Killed After Equipment Collapses

A patient at a veteran's hospital in the Bronx was killed Wednesday when a large piece of diagnostic equipment fell on him in what experts called a rare accident.

The 66-year-old victim was undergoing a procedure using a gamma camera at the James J. Peters VA Medical Center when the apparatus apparently collapsed and crushed him, officials said.

In a statement, a spokesman for the medical center said the camera was installed in 2006 and was maintained by its manufacturer. "This is a very tragic and unusual event and the details are still unfolding," said Jim Connell, a hospital spokesman.

He declined to identify the patient, citing privacy laws.

According to the New York Fire Department, a 911 call for an ambulance came from the hospital on West Kingsbridge Road at about 12:30 p.m. on Wednesday, but was quickly called off. A spokeswoman for the New York City Medical Examiner said an autopsy hadn't yet been completed and that the victim hasn't been formally identified by next of kin.

An official with knowledge of the matter said the camera was a Infinia Hawkeye 4 model, manufactured by General Electric Co. The Hawkeye line is one of the largest on the market and can weigh more than 5,000 pounds.

Mr. Connell said the camera had been used in diagnostic procedures "without incident."

fMRI of brain at rest reveals early signs of Alzheimer's

Functional MRI (fMRI) scans of the brain at rest show disruptions in neural networks in patients with early Alzheimer's disease at about the same time as chemical markers of the disease begin to appear in cerebrospinal fluid, according to a study published online August 19 in JAMA Neurology.

The researchers from Washington University in St. Louis assessed resting-state brain fMRI along with the presence of beta-amyloid plaque and tau protein in the cerebrospinal fluid to detect the early onset of Alzheimer's disease.

The findings are among the first to show how resting-state fMRI may be an equally effective and less invasive way to detect early development of the disease, according to Dr. Liang Wang, from the department of neurology, and colleagues.

A set of brain areas that are active at rest and share a similar timecourse of activity is shown. The top row represents the average “resting state network” from a group of 15 healthy controls, the middle row 14 schizophrenia patients, and the bottom row 17 bipolar disorder patients. It is clear that there are broad similarities in the brain areas in this network across conditions, but there are also subtle differences, which we are currently investigating.

PET/MRI helps with pulmonary nodule detection -- to a point

Simultaneous PET/MRI performs better than PET and MRI performed separately for the detection of FDG-avid pulmonary nodules and lesions at least 0.5 cm in size. However, it has problems with non-FDG-avid nodules and smaller lesions, researchers report in the September issue of Radiology.

Simultaneous PET/MRI identified 86 (96%) of 90 FDG-avid pulmonary nodules and 78 (89%) of 88 nodules with a diameter of 0.5 cm or larger, in the study from NYU Langone Medical Center in New York City.

PET/MRI was less proficient in finding lesions smaller than 0.5 cm, achieving a sensitivity of only 38% (19 of 50 nodules), and it had a sensitivity of only 23% (11 of 48) for nodules that were not FDG-avid (Radiology, Vol. 268:3, pp. 874-881).

PET/MRI of a 63-year-old man with a history of lung cancer who underwent diagnostic PET/CT to assess tumor burden. Image shows a left upper lobe lesion (large arrow). A right upper lobe lesion was also found due to FDG avidity. Image courtesy of Radiology.

Functional Maps of Fetal Brain Activity Created Using RSfMRI

Researchers from Wayne State University and the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the NIH reported the success- ful mapping of the functional connectivity (FC) networks of fetal brains. Using rest- ing state functional MRI (fMRI) techniques, the team imaged 25 pregnant women during the second and third trimesters. With these techniques, researchers are for the first time able to observe the networks within the brain as they develop.

Breast MRI

In the detection of breast cancer, MRI offers high sensitivity while exposing the patient to no ionizing radiation. It is a painless exam, as minimal or no compression is needed, yet it provides both morphological and functional data.

MR is commonly indicated to:

■ Identify clinically or mammographically occult tumor

■ Stage and plan treatment

■ Detect recurrent tumor

■ Screen high-risk women

■ Evaluate the integrity of breast implants

It is also a valuable tool for guided breast biopsy.