ARRS: Breast MRI proves its merit
CHICAGO—Studies presented May 3 at the annual meeting of the American Roentgen Ray Society (ARRS) demonstrated the utility of breast MRI for multiple applications, including presurgical evaluation of ductal carcinoma in situ (DCIS), biopsy guidance and axillary lymph node staging.
Preoperative bilateral MRI for DCIS
Researchers at Elizabeth Wende Breast Clinic (EWBC), a community-based women’s clinic in Rochester, N.Y., designed a retrospective study to assess the diagnostic performance of bilateral preoperative MRI among patients with DCIS.
They analyzed 278 exams acquired from 2005 to 2009 and considered multiple parameters, including the extent of known cancer and suspicious findings, explained Patricia Somerville, MD, of EWBC.
MRI results matched surgical pathology in 86 percent of cases, reported Somerville, discovering an overestimate of disease in 10 percent of cases and an underestimate of disease in 2.5 percent of cases.
In 30 patients, MRI results indicated additional carcinoma, resulting in surgical management changes. In six patients requiring additional biopsies, MRI data were used to determine the site of the second biopsy.
“It’s very helpful to do MRI presurgically in patients with DCIS,” concluded Somerville.
3T MRI-guided biopsy
University of California, San Diego upgraded from a 1.5T MRI to a 3T MRI for breast biopsies in 2008. After the deployment, Haydee Ojeda-Fournier, MD, of the radiology department, designed a retrospective study to evaluate outcomes of performing MRI-guided biopsies on the 3T system.
Historical data have indicated cancer detection rates ranging from 18 percent to 29 percent on 1.5T systems; however, data evaluating breast MRI-guided biopsy in the 3T environment are sparse, offered Ojeda-Fournier.
The study entailed a retrospective review of initial data, biopsy images, biopsy results and surgical pathology for 115 patients referred for MRI-guided biopsy between June 1, 2008 and June 30, 2010.
Twenty percent of the lesions were determined to be malignant, shared Ojeda-Fournier, with contrast-enhanced MRI finding lesions not visible on other modalities. Average biopsy time in the 3T system was 22 minutes.
“MRI-guided biopsy can be performed safely, quickly and efficiently in both the 1.5T and 3T environment,” summed Ojeda-Fournier, who added, “Improved resolution of 3T MRI may have led to lower rates of biopsy referral.”
Axillary lymph node staging
Radiologists have leveraged both ultrasound and MRI for axillary lymph node staging of women diagnosed with invasive breast cancer.
Hiroyuki Abe, MD, from the University of Chicago, and colleagues sought to compare both modalities and undertook a retrospective review of imaging and clinical data for 50 patients diagnosed with invasive breast cancer.
Two radiologists without knowledge of pathology or lymph node staging independently reviewed the imaging data. Sixteen patients had positive lymph nodes.
Ultrasound images yielded two false positives, compared with five via MRI. In addition, ultrasound produced seven false negatives compared with five on MRI datasets.
Ultimately, ultrasound detected nine of 16 true positives, while MRI detected 11 of 16 true positives. Findings were concordant for 42 cases, which yielded higher positive predictive value than discordant cases.
“Sensitivity was higher in MRI datasets, but specificity was higher in ultrasound images,” noted Abe. “Although there is no statistical difference between the two modalities, MRI may be more sensitive.” Abe hypothesized that MRI may be more sensitive because the whole axilla is scanned and image data can be compared with the contralateral breast.
Abe further conjectured that ultrasound may offer higher specificity because of higher resolution, real-time scanning capabilities and inclusion of vascular scanning with Doppler scan.
Preoperative bilateral MRI for DCIS
Researchers at Elizabeth Wende Breast Clinic (EWBC), a community-based women’s clinic in Rochester, N.Y., designed a retrospective study to assess the diagnostic performance of bilateral preoperative MRI among patients with DCIS.
They analyzed 278 exams acquired from 2005 to 2009 and considered multiple parameters, including the extent of known cancer and suspicious findings, explained Patricia Somerville, MD, of EWBC.
MRI results matched surgical pathology in 86 percent of cases, reported Somerville, discovering an overestimate of disease in 10 percent of cases and an underestimate of disease in 2.5 percent of cases.
In 30 patients, MRI results indicated additional carcinoma, resulting in surgical management changes. In six patients requiring additional biopsies, MRI data were used to determine the site of the second biopsy.
“It’s very helpful to do MRI presurgically in patients with DCIS,” concluded Somerville.
3T MRI-guided biopsy
University of California, San Diego upgraded from a 1.5T MRI to a 3T MRI for breast biopsies in 2008. After the deployment, Haydee Ojeda-Fournier, MD, of the radiology department, designed a retrospective study to evaluate outcomes of performing MRI-guided biopsies on the 3T system.
Historical data have indicated cancer detection rates ranging from 18 percent to 29 percent on 1.5T systems; however, data evaluating breast MRI-guided biopsy in the 3T environment are sparse, offered Ojeda-Fournier.
The study entailed a retrospective review of initial data, biopsy images, biopsy results and surgical pathology for 115 patients referred for MRI-guided biopsy between June 1, 2008 and June 30, 2010.
Twenty percent of the lesions were determined to be malignant, shared Ojeda-Fournier, with contrast-enhanced MRI finding lesions not visible on other modalities. Average biopsy time in the 3T system was 22 minutes.
“MRI-guided biopsy can be performed safely, quickly and efficiently in both the 1.5T and 3T environment,” summed Ojeda-Fournier, who added, “Improved resolution of 3T MRI may have led to lower rates of biopsy referral.”
Axillary lymph node staging
Radiologists have leveraged both ultrasound and MRI for axillary lymph node staging of women diagnosed with invasive breast cancer.
Hiroyuki Abe, MD, from the University of Chicago, and colleagues sought to compare both modalities and undertook a retrospective review of imaging and clinical data for 50 patients diagnosed with invasive breast cancer.
Two radiologists without knowledge of pathology or lymph node staging independently reviewed the imaging data. Sixteen patients had positive lymph nodes.
Ultrasound images yielded two false positives, compared with five via MRI. In addition, ultrasound produced seven false negatives compared with five on MRI datasets.
Ultimately, ultrasound detected nine of 16 true positives, while MRI detected 11 of 16 true positives. Findings were concordant for 42 cases, which yielded higher positive predictive value than discordant cases.
“Sensitivity was higher in MRI datasets, but specificity was higher in ultrasound images,” noted Abe. “Although there is no statistical difference between the two modalities, MRI may be more sensitive.” Abe hypothesized that MRI may be more sensitive because the whole axilla is scanned and image data can be compared with the contralateral breast.
Abe further conjectured that ultrasound may offer higher specificity because of higher resolution, real-time scanning capabilities and inclusion of vascular scanning with Doppler scan.