Magnetic resonance imaging in breast cancer

Simultaneous ultrasound and MRI system for breast biopsy: compatibility assessment and demonstration in a dual modality phantom

Simultaneous capturing of ultrasound (US) and magnetic resonance (MR) images allows fusion of information obtained from both modalities. We propose an MR-compatible US system where MR images are acquired in a known orientation with respect to the US imaging plane and concurrent real-time imaging can be achieved. Compatibility of the two imaging devices is a major issue in the physical setup. Tests were performed to quantify the radio frequency (RF) noise introduced in MR and US images, with the US system used in conjunction with MRI scanner of different field strengths (0.5 T and 3 T). Furthermore, simultaneous imaging was performed on a dual modality breast phantom in the 0.5 T open bore and 3 T close bore MRI systems to aid needle-guided breast biopsy. Fiducial based passive tracking and electromagnetic based active tracking were used in 3 T and 0.5 T, respectively, to establish the location and orientation of the US probe inside the magnet bore. Our results indicate that simultaneous US and MR imaging are feasible with properly-designed shielding, resulting in negligible broadband noise and minimal periodic RF noise in both modalities. US can be used for real time display of the needle trajectory, while MRI can be used to confirm needle placement.

Inflammatory breast carcinoma in magnetic resonance imaging: a comparison with locally advanced breast cancer

RATIONALE AND OBJECTIVES

Although inflammatory breast carcinoma (IBC) accounts for 1%-4% of all breast cancer cases, the appearance of this highly malignant tumor in magnetic resonance imaging (MRI) is still not well characterized. The aim of this study was to identify typical imaging features of IBC in comparison with noninflammatory locally advanced breast carcinoma (LABC).

MATERIALS AND METHODS

MRIs of 48 patients with IBC were compared with an equivalent cohort of 52 subjects with LABC. Age and histopathologic subtype were equivalent between the two groups. To delineate characteristic features, a multitude of dynamic and morphologic parameters were evaluated using T1- and T2-weighted sequences.

RESULTS

No significant differences of prevalences could be found for the following criteria: dynamic tumor signal characteristics, prominent vessels, perifocal edema, axillary lymph node involvement, morphology of focal masses, and morphologic pattern of non-mass like enhancement. Otherwise, the quantity of focal masses and the spatial distribution of the tumoral infiltration significantly differed between the two cancer groups. The following parameters occurred more frequently in the IBC cases: edema (cutaneous/subcutaneous 81.3%, perimamillar 70.8%, diffuse 89.6%, prepectoral 72.9%, intramuscular pectoral 41.7%), thickening (75.0%) and pathologic enhancement (60.4%) of Cooper's ligaments, skin thickening (83.3%), punched-out sign (initially strong, focal increase of some dermal or subcutaneous parts followed by slow-continuous enhancement of the surrounding skin; 56.3%).

CONCLUSIONS

Inflammatory breast carcinoma seems to represent a specific biological entity resulting in typical MRI characteristics. Some of the parameters are supposed to visualize the characteristic extensive lymphovascular infiltration and therefore may improve the diagnosis of IBC.

A decade of change: an institutional experience with breast surgery in 1995 and 2005

INTRODUCTION

With the adoption of routine screening mammography, breast cancers are being diagnosed at earlier stages, with DCIS now accouting for 22.5% of all newly diagnosed breast cancers. This has been attributed to both increased breast cancer awareness and improvements in breast imaging techniques. How have these changes, including the increased use of image-guided sampling techniques, influenced the clinical practice of breast surgery?

METHODS

The institutional pathology database was queried for all breast surgeries, including breast reconstruction, performed in 1995 and 2005. Cosmetic procedures were excluded. The results were analysed utilizing the Chi-square test.

RESULTS

Surgical indications changed during 10-year study period, with an increase in preoperatively diagnosed cancers undergoing definitive surgical management. ADH, and to a lesser extent, ALH, became indications for surgical excision. Fewer surgical biopsies were performed for indeterminate abnormalities on breast imaging, due to the introduction of stereotactic large core biopsy. While the rate of benign breast biopsies remained constant, there was a higher percentage of precancerous and DCIS cases in 2005. The overall rate of mastectomy decreased from 36.8% in 1995 to 14.5% in 2005. With the increase in sentinel node procedures, the rate of ALND dropped from 18.3% to 13.7%. Accompanying the increased recognition of early-stage cancers, the rate of positive ALND also decreased, from 43.3% to 25.0%.

CONCLUSIONS

While the rate of benign breast biopsies has remained constant over a recent 10-year period, fewer diagnostic surgical image-guided biopsies were performed in 2005. A greater percentage of patients with breast cancer or preinvasive disease have these diagnoses determined before surgery. More preinvasive and Stage 0 cancers are undergoing surgical management. Earlier stage invasive cancers are being detected, reflected by the lower incidence of axillary nodal metastases.

Signal intensity of normal breast tissue at MR mammography on midfield: applying a random coefficient model evaluating the effect of doubling the contrast dose

PURPOSE

To prospectively investigate the effect on signal intensity (SI) of healthy breast parenchyma on magnetic resonance mammography (MRM) when doubling the contrast dose from 0.1 to 0.2 mmol/kg bodyweight.

MATERIALS AND METHODS

Informed consent and institutional review board approval were obtained. Twenty-five healthy female volunteers (median age: 24 years (range: 21-37 years) and median bodyweight: 65 kg (51-80 kg)) completed two dynamic MRM examinations on a 0.6T open scanner. The inter-examination time was 24 h (23.5-25 h). The following sequences were applied: axial T2W TSE and an axial dynamic T1W FFED, with a total of seven frames. At day 1, an i.v. gadolinium (Gd) bolus injection of 0.1 mmol/kg bodyweight (Omniscan) (low) was administered. On day 2, the contrast dose was increased to 0.2 mmol/kg (high). Injection rate was 2 mL/s (day 1) and 4 mL/s (day 2). Any use of estrogen containing oral contraceptives (ECOC) was recorded. Post-processing with automated subtraction, manually traced ROI (region of interest) and recording of the SI was performed. A random coefficient model was applied.

RESULTS

We found an SI increase of 24.2% and 40% following the low and high dose, respectively (P<0.0001); corresponding to a 65% (95% CI: 37-99%) SI increase, indicating a moderate saturation. Although not statistically significant (P=0.06), the results indicated a tendency, towards lower maximal SI in the breast parenchyma of ECOC users compared to non-ECOC users.

CONCLUSION

We conclude that the contrast dose can be increased from 0.1 to 0.2 mmol/kg bodyweight, if a better contrast/noise relation is desired but increasing the contrast dose above 0.2 mmol/kg bodyweight is not likely to improve the enhancement substantially due to the moderate saturation observed. Further research is needed to determine the impact of ECOC on the relative enhancement ratio, and further studies are needed to determine if a possible use of ECOC should be considered a compromising factor, if an MRM is indicated in a young woman.

Intra-operative sonography: a valuable aid during breast-conserving surgery for occult breast cancer

BACKGROUND

Breast cancer is increasingly detected during an early non-palpable stage. Together with pre-operative marking of the mass, intra-operative imaging provides invaluable clues. This study was designed to evaluate the usefulness of intra-operative sonography in the hands of the surgeon.

METHODS

Between July 2001 and October 2006, 567 patients underwent treatment for operable breast cancer at the landeskrankenhaus (LHK) Feldkirch. Three hundred and sixty lesions were not palpable. Two hundred and ninety-nine patients with poorly definable or non-definable lesions well seen by ultrasound imaging underwent intra-operative sonography (group 1), while 61 patients with non-palpable lesions only seen on mammography (group 2) were subjected to pre-operative needle localization. The study was non-randomized with prospective data acquisition

RESULTS

All lesions were identified by both sonography and pre-operative needle localization. In the ultrasound group (group 1) 81% of the lesions were successfully removed by primary intention without metachronous secondary surgery versus 62% in group 2 (p < 0.00228). Eighty-eight percent of the lesions in group 1 were eligible for breast-conserving surgery versus 75% in group 2. The mean clear margin in group 1 was substantially smaller (4.8 mm) than in group 2 (7.2 mm) (p < 0.0001).

CONCLUSION

Intra-operative sonography proved to be a reliable and helpful tool in the hands of the surgeon, not only for tumor localization, but also for orientation during tumor excision. It simplifies organizational work and spares the patient the discomfort of pre-operative needle localization.

[Upper limb lymphedema revealing breast cancer]

INTRODUCTION

Upper limb lymphedema occurs in 15 to 20% of patients after breast cancer treatment. Upper limb lymphedema without any history of neoplasia is an unusual situation. In this situation, breast cancer should be suspected.

EXEGESIS

We reported two women, 53 and 67 years old, who developed upper limb lymphedema, 18 and 8 months before the diagnosis of breast cancer. In the two cases, clinical examination (breast and axillary palpation) was normal. In one case, mammography led to the diagnosis and in the other breast MRI was required to confirm the cancer.

DISCUSSION

Upper limb lymphedema may be the presenting clinical feature of breast cancer. Breast cancer should be actively sought despite normal clinical and radiological findings. Breast MRI is required in this situation.

Breast Cancer: Pre- and Postoperative Imaging for Staging

Mammography is considered the "gold standard" in the evaluation of the breast from an imaging perspective. Multiple studies have demonstrated the benefit of mammography in detecting smaller cancers, leading to identification of early-stage breast cancers, which largely accounts for decreased mortality from breast cancer and the increased rate of breast conservation. Identification of a suspicious lesion on a mammogram prompts further evaluation including additional mammographic views, ultrasound examination, and biopsy. Recently, MRI and positron emission tomography are being offered as adjuncts to the preoperative workup to better stage the patient; however, there is still controversy over the most appropriate use of these modalities.