Mamma Magnetic Resonance Imaging

Heat Magnetic resonance imaging (MRI) of the mamma (synonyms: Mamma MRI; magnetic resonance mammography (MRM; magnetic resonance imaging – mamma; mammary magnetic resonance imaging; mammary MRI; MR mammography; MRI mammography) – or also called nuclear magnetic resonance imaging (NMR) of the mamma – refers to a radiological examination procedure in which a magnetic field is used to image the structures of the female breast, axilla, and thoracic wall. However, MRI is usually not the diagnostic tool of first choice. Before that, in many cases, other diagnostics such as sonography (ultrasound) or a mammogram are performed.

Indications (areas of application)

  • High-risk patients with familial breast carcinoma* (breast cancer).
  • Clarification of suspicious mammography findings (X-ray examination of the breast).
  • Women younger than 40 years (to optimize locoregional spread diagnosis)/high parenchymal density.
  • Zust. n. implantation of breast implants (especially with prepectoral inserted silicone pads) and after breast-conserving surgery.
  • Primary tumor search in CUP (“carcinoma of unknown primary”) syndrome: In distant metastases – daughter tumors outside the mammary glands or detection of cancer cells in the axilla – , in which no detection of the tumor by mammography or mammasonography has occurred.
  • Follow-up (phase after surgery has been performed): for differential diagnosis.between surgical scars and possible, regrowing tumor foci.

* Detectability limit: > 3 mm: if MRM does not detect a malignant (breast-like) tumor, then in fact in 99% there is no invasive malignant tumor in a size greater than three millimeters.

Contraindications

The usual contraindications apply to a breast MRI as they do to any MRI examination:

  • Cardiac pacemakers (with exceptions).
  • Mechanical artificial heart valves (with exceptions).
  • ICD (implanted defibrillator)
  • Metallic foreign body in dangerous localization (e.g., in close proximity to vessels or eyeball)
  • Other implants such as: Cochlear/ocular implant, implanted infusion pumps, vascular clips, Swan-Ganz catheters, epicardial wires, neurostimulators, etc.

Contrast administration should be avoided in cases of severe renal insufficiency (renal impairment) and existing pregnancy.

The procedure

Magnetic resonance imaging is one of the non-invasive imaging procedures, meaning that it does not penetrate the body. By using the magnetic field, protons (primarily hydrogen) are excited in the body to produce nuclear magnetic resonance. This is a change in the orientation of the particle due to a magnetic field. This is picked up as a signal by the coils placed around the body during the examination and sent to the computer, which calculates the exact image of the body region from the many measurements that take place during an examination. In these images, the differences in the shades of gray are thus caused by the distribution of hydrogen ions. In MRI, one can distinguish between different imaging techniques, such as T1-weighted and T2-weighted sequences. MRI provides very good visualization of soft tissue structures. A contrast agent can be administered for even better differentiation of tissue types. Thus, the radiologist can obtain even more detailed information about any disease processes that may be present through this examination. The examination usually takes about half an hour and is performed with the patient lying down. During the examination, the patient is in a closed room in which there is a strong magnetic field. Since the MRI machine is relatively loud, headphones are placed on the patient. In the presence of breast carcinoma, the intravenous contrast agent can be used to detect pathological enhancement (“pathological accumulation of contrast agent in the examined structures”) caused by tumor angiogenesis (new vessel formation by the tumor) and increased vascular permeability of malignant (“malignant”) lesions. Magnetic resonance imaging can distinguish scarring from recurrence (recurrence of tumor disease). The sensitivity for detecting invasive carcinoma with MR mammography is greater than 98%. The MRI examination is performed in the prone position and takes approximately 30 minutes. In fast-track MRI, the examination takes just under 3 minutes.Note: Learn to recognize possible changes through regular attentive observation of the breast and self-palping of the breast and armpit. You will learn to take care of yourself and your female body and feel more confident, comfortable and attractive and beautiful for a long time to come.

Possible complications

Ferromagnetic metal bodies (including metallic makeup or tattoos) can lead to local heat buildup and possibly cause paresthesia-like sensations (tingling). Further notes

  • Scientists at the German Cancer Research Center (DKFZ) in Heidelberg compared MRI images with biopsy (specimen collection) results and demonstrated that additional breast MRI correctly classified more than 90% of abnormal findings. This is compared to the rate of 50% as achieved with mammography (X-ray examination of the breast) and subsequent mammary ultrasound (breast ultrasound), a big increase.
  • MRI sensitivity (percentage of diseased patients in whom the disease is detected by the use of the test, i.e., a positive test result occurs) for breast carcinomas reaches values up to 100%. On the other hand, an MRI of the breast has a relatively low specificity (probability that actually healthy people who do not have the disease in question will be detected as healthy in the test), resulting in a high rate of false-positive findings, i.e., benign (benign) rather than malignant (malignant) changes.
  • According to one study (based on MRI results of 2,316 abnormalities of the breast), a breast MRI for suspected breast cancer achieves a sensitivity of 99%, a specificity of 89%, a positive predictive value of 56%, and a negative predictive value of 100%, meaning that negative findings can be relied upon and positive findings are less informative.
  • Additional magnetic resonance imaging (MRI) halved the number of interval cancers in a randomized mammography study of women with extremely radiopaque mammary glands (grade 4 in the Volpara software classification). A drawback was the high rate of false-positive findings on MRI:
    • Positive predictive value (proportion of women “suspected” on MRI who actually had breast cancer): 17.4% (based on biopsies (tissue samples): 26.3%, meaning that in 73.7% of cases, the biopsy was performed unnecessarily)
  • One study examined the frequency with which women within a high-screening program were diagnosed with breast carcinomas that were not apparent on previous MRI. This involved reevaluating the MRI images of 131 women who had previously been diagnosed with breast tumors (76 by MRI, 13 by mammography; 16 interval carcinomas and 26 incidental carcinomas). Follow-up by experienced radiologists revealed that 34% of previous MRI images had no evidence of breast carcinoma, 34% had minimal signs (BI-RADS-2: 49%; BI-RADS-3: 51%), and 31% (BI-RADS-3: 5%, BI-RADS-4: 85%, BI-RADS-5: 10%) had visible lesions. At reevaluation, 49% of MRI scans previously assessed as negative were assessed as ≥ BI-RADS-% (= high probability of carcinoma presence). An interesting aspect of the study is that BRCA-positive patients were significantly less likely to be missed than BRCA-negative patients (19 versus 46%).Note: BI-RADS classification see below Mammography.
  • In a retrospective analysis of breast MRIs, incisional (incidental) MRI findings in extramammary (outside the mammary gland) areas were found in nearly 11% of cases, distributed as follows: Liver (60%), thoracic cavity (34.3%), musculoskeletal system (9%), neck (3%), and kidney (3%). In no case was it a metastasis of the previously diagnosed breast carcinoma or any other malignancy.
  • An abbreviated and focused form of magnetic resonance imaging (MRI; abbreviated breast magnet resonance imaging, AB-MR) can detect significantly more invasive breast tumors than digital tomosynthesis in women with dense mammaries. AB-MR detected all invasive tumors in 17 women, whereas tomosynthesis did so in only 7; factor of 2.5 better detection rate (detection rate); for precursors of invasive carcinomas (ductal carcinomata in-situ or DCIS), AB-MR was three times more sensitive than tomosynthesis.
  • A supplemental MRI scan in women with very dense breast tissue may reduce the rate of interval carcinomas.Note: Interval carcinomas are carcinomas that occur between the index mammogram and the scheduled follow-up interval.