PET/MR beats PET/CT at imaging suspected occult tumors

PET/MR has proven more precise than PET/CT in a prospective study comparing the modalities on their in-practice utility for clarifying the workup of cancers of unknown primary origin, according to research published online Dec. 3 in Clinical Nuclear Medicine.

Tetsuro Sekine, MD, PhD, of the University of Zurich in Switzerland and Nippon Medical School in Japan and colleagues performed sequential PET/CT and PET/MR in 43 patients who were referred for suspected occult primary tumors.

The team assessed the patients (22 males, 21 females; median age, 58 years; range, 20-86 years) with the two modalities augmented by the contrast agent fludeoxyglucose (FDG), seeking the presence or absence of a primary tumor, lymph node metastases and/or distant metastases.

They found a primary lesion 14 patients. In 16 patients, the primary lesion remained occult, and, in the remaining 13, the lesions proved benign.

As for the comparison, PET/MR beat PET/CT at primary tumor detection (sensitivity/specificity, 0.85/0.97 vs. 0.69/0.73; P = 0.020).

It was comparable to PET/CT for the detection of lymph node metastases (sensitivity/specificity, 0.93/1.00 vs. 0.93/0.93; P = 0.157) and distant metastases (sensitivity/specificity, 1.00/0.97 vs. 0.82/1.00; P = 0.564).

And PET/CT “tended to misclassify physiologic uptake of FDG as malignancy compared with PET/MR (8 patients vs. 1 patient),” write the authors, whose specialties included nuclear medicine and neuroradiology as well as diagnostic and interventional radiology.

“PET/MR may replace PET/CT to improve clinical workflow,” they conclude. 

Dave Pearson

Dave P. has worked in journalism, marketing and public relations for more than 30 years, frequently concentrating on hospitals, healthcare technology and Catholic communications. He has also specialized in fundraising communications, ghostwriting for CEOs of local, national and global charities, nonprofits and foundations.

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