Molecular MRI Adds Certainty to Cancer Diagnosis

MRI has become an important tool in the detection, diagnosis, and treatment planning for many cancers, especially solid tumors. However, up until now, a lack of specificity has held back the full potential of MRI.  

While MRI is very good at identifying areas of interest, factors such as infection, benign tumors, post-traumatic areas, and inflammation can all increase vascularity and, therefore, enhancement of contrast and signal changes.  

  • As a result, MRI has a high rate of false positives – findings that may be flagged as something of concern but that are not necessarily malignant lesions.  

This lack of accuracy results in clinical care teams performing too many confirmatory biopsies, with most being benign.

Now a novel class of molecular imaging contrast agents developed by Imagion Biosystems brings a new level of specificity to MRI. 

  • The company’s MagSense imaging agents have the potential to improve the clinical utility of the large installed base of MRI systems across the globe through improved accuracy of interpretation, avoiding biopsies of benign lesions, driving earlier intervention and improving outcomes and quality of life.

Unlike gadolinium-based agents that non-specifically enhance tissue vascularity regardless of cause, MagSense imaging agents target receptors on cancer cells.  

  • By combining magnetic nanoparticles that have high susceptibility and r2 relaxivity with cancer-specific biomarkers, molecular MRI becomes possible.

Imagion’s superparamagnetic iron oxide nanoparticles are coated with a cancer-specific targeting moiety, such as an antibody or peptide.

  • The cancer biomarker molecule causes the particles to bind to target-specific cancer cells, if present. If the lesion in question is not the target cancer, the particles do not bind.

Where the imaging agent has become attached to the tissue, the nanoparticles produce an identifiable change in MRI signal. 

  • This signal is easily detected by radiological review and can be quantitatively assessed.

Imagion has developed cancer-specific contrast imaging agents for HER2 breast cancer, prostate cancer, and ovarian cancer, and the MagSense platform can be adapted for any type of cancer for which there is a targeting moiety.  

  • Imagion is now preparing to initiate a multisite phase 2 study in the U.S. in HER2+ breast cancer patients to optimize imaging parameters and compare MagSense imaging to the standard of care.  

The Takeaway

Molecular-specific imaging agents like the MagSense technology from Imagion Biosystems create the opportunity for molecular MRI to fundamentally change how radiologists detect and monitor cancers. 

The company is publicly traded (ASX:IBX) and is looking to expand its U.S. investor base as it advances through its clinical programs. To become involved as an investigator or investor or to learn more visit their website.

ACR Grants NPPs’ Contrast Supervision

The American College of Radiology (ACR) rolled out a significant change to its imaging contrast guidelines, allowing non-radiologists and non-physician practitioners (NPPs) to supervise intravenous CT and MRI contrast administration at accredited imaging centers.

A range of NPPs (NPs, PAs, RNs) and qualifying non-radiologist physicians will be able to directly supervise contrast administration under the “general supervision” of on-site radiologists, as long as it’s supported by state scope of practice laws. 

  • Superving radiologists must be available for “assistance or direction” and trained to handle acute contrast reactions/situations, but they won’t have to be in the same room as the patient.

These guidelines mirror the ACR’s new practice parameters for contrast supervision (adopted in May), and follow CMS’ recent efforts to expand more diagnostic tasks to non-physicians.

  • CMS granted radiology assistants the ability perform a range of imaging tasks in 2020 and permitted NPPs to directly supervise Level 2 tests in 2021 (like contrast-enhanced CT and MRI), in both cases requiring “general” radiologist supervision (on-site, but not in room… and virtual during the pandemic).

Although NPPs’ radiology expansion has historically sparked heated debates, the new ACR contrast supervision guidelines hasn’t faced many public objections so far. 

  • That’s potentially because some (busy) radiologists don’t view directly supervising contrast administration as a practical or efficient use of their time (even if they still have to drive to the imaging center), especially considering that technologists often spot adverse reactions before anyone else.
  • However, there’s surely plenty of radiologists who are concerned about whether these new guidelines might exacerbate scope creep, cut their earning potential (especially trainees), reduce radiologists’ patient-facing opportunities, and undermine patient care.

The Takeaway

The ACR’s decision to grant NPPs greater contrast supervision rights and loosen radiologists’ contrast supervision requirements might not be surprising to folks paying attention to recent ACR and CMS policies. That said, it’s still a notable step (and potential contributor) in the NPPs’ expanding role within radiology – and opinions might differ regarding whether that’s a good thing.

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