Susanne Wurdinger

Potential MRI Interpretation Model: Differentiation of Benign from Malignant Breast Masses

OBJECTIVE Our objective was to increase the accuracy of breast MRI using a semiquantitative analysis of typical MRI features and their diagnostic potential. The prevalence of recently reported MRI signs of breast lesions were analyzed and compared with other well-known signs. CONCLUSION New MRI features, especially from T2-weighted images, are promising for more reliable and accurate interpretation of breast lesions. Prospective studies of these findings are required to define cut-off values and test clinical practicality.

Comparison of written reports of mammography, sonography and magnetic resonance mammography for preoperative evaluation of breast lesions, with special emphasis on magnetic resonance mammography

Patients with abnormal breast findings (n = 413) were examined by mammography, sonography and magnetic resonance (MR) mammography; 185 invasive cancers, 38 carcinoma in situ and 254 benign tumours were confirmed histologically. Sensitivity for mammography was 83.7%, for sonography it was 89.1% and for MR mammography it was 94.6% for invasive cancers. In 42 patients with multifocal invasive cancers, multifocality had been detected by mammography and sonography in 26.2%, and by MR mammography in 66.7%. In nine patients with multicentric cancers, detection rates were 55.5, 55.5 and 88.8%, respectively. Carcinoma in situ was diagnosed by mammography in 78.9% and by MR mammography in 68.4% of patients. Combination of all three diagnostic methods lead to the best results for detection of invasive cancer and multifocal disease. However, sensitivity of mammography and sonography combined was identical to that of MR mammography (ie 94.6%).

Differentiation of Phyllodes Breast Tumors from Fibroadenomas on MRI

OBJECTIVE The purpose of our study was to evaluate the MRI appearance of phyllodes breast tumors and to differentiate them from fibroadenomas. MATERIALS AND METHODS MR images were obtained on a 1.5-T imager. T1- and T2-weighted sequences and dynamic 2D fast-field echo T1-weighted sequences were performed. MR images of 23 patients with 24 phyllodes breast tumors (one malignant, 23 benign) were analyzed with respect to morphology and contrast enhancement. The tumors were compared with the MRI appearance of 81 fibroadenomas of 75 patients. RESULTS Well-defined margins were seen in 87.5% of the phyllodes tumors and 70.4% of the fibroadenomas, and a round or lobulated shape in 100% and 90.1%, respectively. A heterogeneous internal structure was observed in 70.8% of phyllodes tumors and in 49.4% of fibroadenomas. Nonenhancing internal septations were found in 45.8% of phyllodes tumors and 27.2% of fibroadenomas. A significantly greater increase in signal was seen on T2-weighted images in the tissue surrounding phyllodes tumors (21%) compared with fibroadenomas (1.2%). Most of both lesions appeared with low signal intensity on T1- and T2-weighted images. After the administration of contrast material, 33.3% of phyllodes tumors and 22.2% of fibroadenomas showed a suspicious signal intensity-time course. CONCLUSION Phyllodes breast tumors and other fibroadenomas cannot be precisely differentiated on breast MRI. Phyllodes tumors have benign morphologic features and contrast enhancement characteristics suggestive of malignancy in 33% of cases.

Further signs in the evaluation of magnetic resonance mammography: a retrospective study.

Purpose:To increase accuracy and reliability of magnetic resonance breast imaging, a new evaluation method might be helpful. The recently suggested evaluation method (Fischer U, et al) resulted in a relevant number of equivocal cases (3 or 4 points). Additional morphologic and dynamic signs as an extension of this score were evaluated. Method and Materials:One hundred thirty-two histologically verified lesions were evaluated by 3 radiologists double-blinded using 2 evaluation methods: 1) method 1 (according to Fischer, et al): 2pt: initial signal increase >100%, washout, centripetal enhancement, 1pt: initial signal increase 50–100%, plateau phenomenon, centrifugal inhomogeneous enhancement, irregular borders, linear, stellar or dendritic structure; and 2) method 2 (according to Malich, et al): 3pt: hook sign (sign of pectoral invasion), 2pt: unifocal edema, blooming. 1pt: hypointensity in T2, lymph nodes >10 mm, skin thickening, adjacent vessels, a lesions distorted inner architecture, disruption of the mamillary edge; −1pt: isointensity in T2, no edema, enhancing septations; −3pt: hyperintensity in T2, non enhancing septations. Method 1 judged a lesion to be malignant if 5 or more points were given and benign if 2 or less points were given, respectively. Method 2 (mean value of 3 radiologists) was tested in those cases in which a clear possible decision using method 1 was not sufficiently possible. Results:Method 1 alone resulted in a negative predictive value of 96.8% and a positive predictive value of 90.8% (without carinoma in situ), a sensitivity of 83.1%, a specificity of 58.8%, and revealed uncertain results (3 and 4 points) in 29 cases (out of 132; 22%). Adding the new scoring system in these 29 equivocal cases and an increase of 2 or more points by using method 2 is supposed to be a sign of malignancy; findings suggest a sensitivity of 90.9% and a specificity of 60% if an increase of maximum 1 is observed in benign lesions. In conclusion, our results show that Göttingen score alone has a sensitivity of 83.1%, a specificity of 58.8%; the second evaluation method reveals a sensitivity of 90.9% and a specificity of 60% in equivocal cases of Göttingen score. Göttingen score then reaches in all cases and second, adding the second evaluation method in equivocal cases, a sensitivity of 97% and a specificity of 76.5%. Conclusion:The application of a second evaluation method in those cases remaining unclear in Göttingen score can lead to a decrease of uncertainty and a higher sensitivity and specificity of diagnosis in MR mammography. In this study, Göttingen score reaches a sensitivity of 83.1% and a specificity of 58.8%, increasing to a sensitivity of 97% and a specificity of 76.5% when being extended by a second evaluation method in unclear cases.

MRI of the pelvic ring joints postpartum: Normal and pathological findings

To assess the joints of the pelvic ring postpartum and to discern normal postpartum findings and pathologic lesions using MRI.

Changes in magnetic resonance mammography due to hormone replacement therapy

BackgroundThe aim of the present article is to investigate effects of hormone replacement therapy (HRT) on contrast medium enhancement patterns in postmenopausal patients during magnetic resonance mammography (MRM).Materials and methodsTwo hundred and fifteen patients receiving hormonal medication were divided into four groups: 150 patients with 1 MRM during HRT (group A), 13 patients with 2 MRMs under HRT (group B), 30 patients with 1 MRM during HRT and 1 MRM after HRT withdrawal (group C), and 22 women with 1 MRM after HRT withdrawal (group D). Dynamic MRM was performed at 1.5 Tesla. Signal intensity changes were characterized by five time curves: minimal enhancement (type I), weak continuous enhancement (type II), strong continuous enhancement (type III), and a steep initial slope followed by a plateau phenomenon (type IV) or a washout effect (type V).ResultsOf all 193 patients under HRT (group A + group B + group C), 60 patients (31.1%) showed curve type I, 88 patients (45.6%) showed type II and 45 patients (23.3%) showed type III. There were significant differences to 52 patients after HRT withdrawal (group C + group D) (P < 0.0001), with 42 patients (80.8%) for curve type I, 8 patients (15.4%) for type II, and 2 patients (3.8%) for type III. In both MRM sessions in group B, 69% of the patients showed identical curve types without significant differences (P = 0.375). In group C, 28 of 30 patients (93%) dropped to lower curve types with significant differences in curve types during and after HRT (P < 0.0001).ConclusionThe majority of patients receiving postmenopausal HRT showed bilateral symmetrical, continuous enhancement without evidence of a plateau phenomenon or a washout effect due to HRT in MRM. Hormonal effects could be proven and were reproducible and reversible.

The Adjacent Vessel on Dynamic Contrast-Enhanced Breast MRI

OBJECTIVE The purpose of this study was to investigate whether an adjacent vessel leading to an enhancing lesion seen on subtraction images can help differentiate malignant from benign breast lesions and therefore increase the specificity of breast MRI. MATERIALS AND METHODS The study included 132 histologically verified lesions (71 malignant lesions, 10 pure carcinoma in situ, and 51 benign lesions) enhancing on dynamic breast MRI before biopsy. The lesions were evaluated by three radiologists in a double-blinded manner. The presence of an adjacent vessel was supposed if at least two observers voted positively. RESULTS Sixty-one (85.9%) of 71 malignant lesions, six (60%) of 10 carcinomas in situ, and 10 (19.6%) of 51 benign lesions were associated with an adjacent vessel, which differed significantly (p < 0.001) between benign and malignant lesions (the latter with and without including pure carcinoma in situ), leading to a positive predictive value of 85.9% (87% including pure carcinomas in situ), a negative predictive value of 80.4% (74.5% including pure carcinomas in situ), an accuracy of 83.2% (81.6% including pure carcinomas in situ), a sensitivity of 85.9% (82.7% including carcinomas in situ), and a specificity of 80.4% for this sign concerning malignancy. CONCLUSION The presence of an adjacent vessel seen on subtraction images promises to be a good marker for malignancy and can therefore help increase the specificity of breast MRI.

Two cases of metastases to the breast on MR mammography

Abstract We report appearance of two cases of metastases to the breast on MR mammography. Metastasis from cervical cancer displayed a hypointense tumor with a central area of high signal intensity on T2-weighted images and rapid annular enhancement with persistent central contrast enhancement. The metastases from rhabdomyosarcoma were characterized by multiple tumors with high signal intensity on T2-weighted images and fast annular contrast enhancement. We show unusual malignant breast lesions for possible identification in dynamic MR mammography.

Comparison of artifacts produced from carbon fiber and titanium alloy needles at 1.5 T MR imaging.

A novel coaxial carbon fiber‐based biopsy needle set was investigated in phantom experiments and compared with a commercially available, magnetic resonance (MR)‐compatible titanium alloy set using MR imaging at 1.5 T. Image artifacts observed with different MR sequences were assessed. It was found that the carbon fibers produced distinctly smaller image artifacts compared with the titanium needle. Depending on the type of MR sequence, the relative range of artifact size ratios between the carbon and titanium needles was between 0.7 (spin‐echo sequence) and 0.4 (gradient‐echo sequence) with the needles oriented perpendicular to the main magnetic field. Carbon fiber composites are promising materials for the design and construction of MR‐compatible instruments. J. Magn. Reson. Imaging 2000;11:69–74.

Application and assessment of a robust elastic motion correction algorithm to dynamic MRI

The purpose of this study was to assess the performance of a new motion correction algorithm. Twenty-five dynamic MR mammography (MRM) data sets and 25 contrast-enhanced three-dimensional peripheral MR angiographic (MRA) data sets which were affected by patient motion of varying severeness were selected retrospectively from routine examinations. Anonymized data were registered by a new experimental elastic motion correction algorithm. The algorithm works by computing a similarity measure for the two volumes that takes into account expected signal changes due to the presence of a contrast agent while penalizing other signal changes caused by patient motion. A conjugate gradient method is used to find the best possible set of motion parameters that maximizes the similarity measures across the entire volume. Images before and after correction were visually evaluated and scored by experienced radiologists with respect to reduction of motion, improvement of image quality, disappearance of existing lesions or creation of artifactual lesions. It was found that the correction improves image quality (76% for MRM and 96% for MRA) and diagnosability (60% for MRM and 96% for MRA).