AJR: PEM studies emphasize ease of use
The American Journal of Roentgenology has published two separate studies this month demonstrating the clinical acceptance of Naviscan’s Positron Emission Mammography (PEM) scanner. The first study concluded that breast radiologists can achieve a high level of diagnostic performance in interpreting PEM images after a two-hour tutorial. The second study established a standard lexicon for the evaluation of PEM images.
PEM scanners are high-resolution breast PET systems that can show the location as well as the metabolic phase of a lesion. The purpose of the interpretative skills study was to prospectively validate how easy it is to learn and standardize the interpretation of PEM by breast radiologists.
Thirty-six observers from 15 sites completed both PEM and MRI interpretive skills tasks. All participants underwent a two-hour training program for interpreting PEM images.
The median sensitivity and specificity for PEM assessment tasks were 100 percent and 83 percent, respectively, compared to the median sensitively and specificity of MRI at 82 percent and 69 percent, respectively, according to Deepa Narayanan, MS, from San Diego-based Naviscan, and colleagues. “The results indicate that, with minimal training, experienced breast imagers showed high performance in interpreting PEM images,” wrote Narayanan and colleagues.
Complementing this study, the lexicon paper outlined a standardized terminology to report PEM findings, similar to the Breast Imaging Reporting and Data System (BI-RADS) developed by the American College of Radiology.
Twenty investigators reviewed 404 malignancies in 388 women with newly diagnosed breast cancer anticipating breast-conserving surgery and compared PEM to MRI in the assessment of disease extent. PEM imaging features of known malignancies and additional PEM lesions were recorded and correlated with outcome. The reference standard was biopsy or a follow-up of six months or longer.
Of 166 additional lesions located via PEM, 54 proved malignant, with a median invasive tumor size of 8 mm. Among 43 round or oval masses, 16 were malignant, compared with 16 of 21 of lobulated or irregular masses. Among 14 findings of focal or regional nonmass uptake, two were malignant compared with four of 12 findings of linear-ductal or segmental uptake. On the basis of modeling, irregular or lobulated morphology was the strongest predictor of malignancy, noted the researchers.
"Use of standardized terminology to report PEM findings will facilitate effective communication of results and consistent management. A probably benign category 3 assessment carried a substantial rate of malignancy for lesions seen on PEM, and biopsy may be more appropriate than follow-up,” concluded Narayanan and colleagues.
"PEM interpretation is relatively simple," concluded Priscilla Slanetz, MD, director of breast imaging research and education at Beth Israel Deaconess Medical Center in Boston. "Assessing for areas of focal uptake typically is straightforward and takes just 1 to 3 minutes at most. In comparison, interpreting breast MR can take anywhere between five and 20 minutes, depending upon the complexity of the case and the number of sequences acquired."
PEM scanners are high-resolution breast PET systems that can show the location as well as the metabolic phase of a lesion. The purpose of the interpretative skills study was to prospectively validate how easy it is to learn and standardize the interpretation of PEM by breast radiologists.
Thirty-six observers from 15 sites completed both PEM and MRI interpretive skills tasks. All participants underwent a two-hour training program for interpreting PEM images.
The median sensitivity and specificity for PEM assessment tasks were 100 percent and 83 percent, respectively, compared to the median sensitively and specificity of MRI at 82 percent and 69 percent, respectively, according to Deepa Narayanan, MS, from San Diego-based Naviscan, and colleagues. “The results indicate that, with minimal training, experienced breast imagers showed high performance in interpreting PEM images,” wrote Narayanan and colleagues.
Complementing this study, the lexicon paper outlined a standardized terminology to report PEM findings, similar to the Breast Imaging Reporting and Data System (BI-RADS) developed by the American College of Radiology.
Twenty investigators reviewed 404 malignancies in 388 women with newly diagnosed breast cancer anticipating breast-conserving surgery and compared PEM to MRI in the assessment of disease extent. PEM imaging features of known malignancies and additional PEM lesions were recorded and correlated with outcome. The reference standard was biopsy or a follow-up of six months or longer.
Of 166 additional lesions located via PEM, 54 proved malignant, with a median invasive tumor size of 8 mm. Among 43 round or oval masses, 16 were malignant, compared with 16 of 21 of lobulated or irregular masses. Among 14 findings of focal or regional nonmass uptake, two were malignant compared with four of 12 findings of linear-ductal or segmental uptake. On the basis of modeling, irregular or lobulated morphology was the strongest predictor of malignancy, noted the researchers.
"Use of standardized terminology to report PEM findings will facilitate effective communication of results and consistent management. A probably benign category 3 assessment carried a substantial rate of malignancy for lesions seen on PEM, and biopsy may be more appropriate than follow-up,” concluded Narayanan and colleagues.
"PEM interpretation is relatively simple," concluded Priscilla Slanetz, MD, director of breast imaging research and education at Beth Israel Deaconess Medical Center in Boston. "Assessing for areas of focal uptake typically is straightforward and takes just 1 to 3 minutes at most. In comparison, interpreting breast MR can take anywhere between five and 20 minutes, depending upon the complexity of the case and the number of sequences acquired."