Pa Baltzer

Clinical MR Mammography: Impact of Hormonal Status on Background Enhancement and Diagnostic Accuracy

PURPOSE Hormonal stimulation can induce background enhancement (BE) in MR mammography (MRM). This fact has been assumed to decrease the accuracy of MRM. Consequently, this report investigates: 1. The prevalence of BE in postmenopausal vs. premenopausal women in correlation to hormonal cycle phase (CP). 2. The impact of hormonal status (HS) and BE on diagnostic accuracy. MATERIALS AND METHODS Consecutive patients over 22 months with complete HS information (week of CP or postmenopausal) were included in this prospective investigation. Exclusion criteria were any hormonal therapy, hysterectomy as well as cancer proven by biopsy. The standard of reference was histopathology. All MRM scans were acquired using the same protocol (1.5 T, dynamic T 1w GRE after 0.1 mmol/kg bw Gd-DTPA i. v.). Two radiologists rated all examinations in consensus according to BI-RADS. BE was defined as: 0 = missing, 1 = moderate, 2 = distinct. RESULTS 224 patients (150 postmenopausal, 74 premenopausal, 45 in the second week of CP) were included in this study (83 benign and 141 malignant findings). BE was more frequent in premenopausal women (p = 0.006), but did not differ between CP (p = 0.460). Neither HS nor BE had a significant impact on the diagnostic parameters of MRM (p ≥ 0.375). However, regarding BE, the relative number of false positive (FP) findings was highest (5 / 10; 50 %) in the distinct BE group. Regarding HS, 17 % more FP findings were observed in premenopausal women examined outside the second week of CP. CONCLUSION In premenopausal women, HS leads to increased BE of breast tissue, independent of CP. Distinct BE and less pronounced, non-optimal CP may lead to an increased number of false positive findings.

Potential of MR mammography to predict tumor grading of invasive breast cancer.

PURPOSE Tumor grading (TG) is one of the most widely used prognostic factors in the case of breast cancer. This study aims to identify the potential of magnetic resonance mammography (MRM) to non-invasively assess TG. MATERIALS AND METHODS 399 invasive breast cancers were included (IRB approval; standardized clinical MRM protocols). All breast cancers were prospectively evaluated by two experienced (> 500 MRM) and blinded radiologists in consensus. In every cancer a set of 18 previously published MRM descriptors was assessed. These were assessed by univariate and multivariate analysis to identify the potential of MRM to predict TG (X2 statistics; binary logistic regression; area under the ROC curve [AUC]). RESULTS 8 of 18 MRM descriptors were associated with TG, e. g. internal structure, edema (p < 0.001), as well as skin thickening and destruction of the nipple line (p < 0.05). MRM was feasible to predict TG by multivariate analysis (p < 0.001). The highest potential could be identified to predict well differentiated breast cancers with good prognosis (AUC = 0.930). CONCLUSION MR mammography was able to non-invasively assess tumor grading in a standard protocol. Since tumor grading is a surrogate for overall survival, these results provide further evidence to the clinical application of MR mammography as a noninvasive prognostic tool.

Can Color-Coded Parametric Maps Improve Dynamic Enhancement Pattern Analysis in MR Mammography?

PURPOSE Post-contrast enhancement characteristics (PEC) are a major criterion for differential diagnosis in MR mammography (MRM). Manual placement of regions of interest (ROIs) to obtain time/signal intensity curves (TSIC) is the standard approach to assess dynamic enhancement data. Computers can automatically calculate the TSIC in every lesion voxel and combine this data to form one color-coded parametric map (CCPM). Thus, the TSIC of the whole lesion can be assessed. This investigation was conducted to compare the diagnostic accuracy (DA) of CCPM with TSIC for the assessment of PEC. MATERIALS AND METHODS 329 consecutive patients with 469 histologically verified lesions were examined. MRM was performed according to a standard protocol (1.5 T, 0.1 mmol/kgbw Gd-DTPA). ROIs were drawn manually within any lesion to calculate the TSIC. CCPMs were created in all patients using dedicated software (CAD Sciences). Both methods were rated by 2 observers in consensus on an ordinal scale. Receiver operating characteristics (ROC) analysis was used to compare both methods. RESULTS The area under the curve (AUC) was significantly (p=0.026) higher for CCPM (0.829) than TSIC (0.749). The sensitivity was 88.5% (CCPM) vs. 82.8% (TSIC), whereas equal specificity levels were found (CCPM: 63.7%, TSIC: 63.0%). CONCLUSION The color-coded parametric maps (CCPMs) showed a significantly higher DA compared to TSIC, in particular the sensitivity could be increased. Therefore, the CCPM method is a feasible approach to assessing dynamic data in MRM and condenses several imaging series into one parametric map.

A systematic comparison of two pulse sequences for edema assessment in MR-mammography

OBJECTIVE Perifocal edema, defined as high T2w signal intensity around an enhancing lesion has been described as a specific feature of malignancy. In clinical MR-mammography (MRM), both fatsat and non-fatsat T2w sequences are available. However, there is no consensus on which technique should be used for edema assessment. Consequently, this investigation was performed to compare two commonly used pulse sequences for edema assessment in MRM. MATERIALS AND METHODS 321 consecutive patients from a 22 month period were included in this investigation. Further selection criteria were histopathological verification of enhancing lesions and absence of presurgical chemotherapy or biopsy, resulting in 108 malignant and 107 benign lesions. All underwent MRM according to international guidelines including a non-fatsat T2w-TSE sequence (TR/TE: 8900/207 ms) and a short tau inversion recovery fatsat sequence (STIR, TR/TE: 8420/70 ms). All images were acquired in the same orientation (axial) and slice thickness. Two experienced radiologists in consensus rated presence of perifocal edema according to an ordinal scale: 0 = not present, 1 = little, 2 = intermediate, and 3 = distinct. Data analysis was performed using crosstabs and Visual Grading Characteristics (VGC) analysis. RESULTS Overall sensitivity/specificity was calculated with 53.7%/94.4% (T2w-TSE) and 52.8%/95.3% (STIR). VGC revealed an area under the VGC curve of 0.502 (standard error 0.026), P = 0.814. CONCLUSION Perifocal edema is a specific feature of malignancy with moderate sensitivity. VGC analysis did not reveal significant differences between both pulse sequences analysed. Consequently, both T2w-TSE and STIR images are suitable for assessment of perifocal edema.

Zukünftige Entwicklungen in der Bildgebung

Die Zukunft technischer Entwicklungen vorhersagen zu wollen ist immer auf einer subjektiven Einschatzung begrundet und daher naturgemas schwierig. Um die Zukunft der Bildgebung abschatzen zu konnen, wird jeweils die aktuelle Situation beleuchtet und davon ausgehend mogliche Entwicklungen dargestellt. Dabei ist ein zentraler Punkt die heute mithilfe von Computersystemen erhobene umfangreiche Menge von Patientendaten, die mit bestehenden Techniken neu verknupft werden.

MRT einschließlich Intervention

Die MRT der Mamma ist das sensitivste Verfahren zur Detektion von Brustkrebs. Ihre hohe Sensitivitat wird uber die Visualisierung der Perfusion des untersuchten Gewebes erreicht. Neuere Studien attestieren der MRT der Mamma durchweg eine hohe, konventionellen Verfahren gleichwertige Spezifitat. Voraussetzung fur gute Ergebnisse in der MRT der Mamma sind einwandfreie Indikationsstellung, technische Durchfuhrung und Erfahrung des Untersuchers.

Differentiation of ductal carcinoma in situ versus fibrocystic changes by magnetic resonance imaging: are there pathognomonic imaging features?

Background In breast magnetic resonance imaging (MRI), the diagnosis of ductal carcinoma in situ (DCIS) remains controversial; the most challenging cause of false-positive DCIS diagnosis is fibrocystic changes (FC). Purpose To search for typical and pathognomonic patterns of DCIS and FC using a standard clinical MRI protocol. Material and Methods Consecutive patients scheduled for breast MRI (standardized protocols @ 1.5T: dynamic-T1-GRE before/after Gd-DTPA [0.1 mmol/kg body weight (BW)]; T1-TSE), with subsequent pathological sampling, were investigated. Sixteen MRI descriptors were prospectively assessed by two experienced radiologists in consensus (blinded to pathology) and explored in patients with DCIS (n = 77) or FC (n = 219). Univariate and multivariate statistics were performed to identify the accuracy of descriptors (alone, combined). Furthermore, pathognomonic descriptor-combinations with an accuracy of 100% were explored (χ2 statistics; decision trees). Results Six breast MRI descriptors significantly differentiated DCIS from FC (Pcorrected < 0.05; odds ratio < 7.9). Pathognomonic imaging features were present in 33.8% (n = 100) of all cases allowing the identification of 42.9% of FC (n = 94). Conclusion Pathognomonic patterns of DCIS and FC were frequently observed in a standard clinical MRI protocol. Such imaging patterns could decrease the false-positive rate of breast MRI and hence might help to decrease the number of unnecessary biopsies in this clinically challenging subgroup.

Trennung von Perfusion und Diffusion in Herdbefunden der Leber – klinische Anwendung zur Differenzierung metastasensuspekter Befunde.

Ziele: Die DWI ermoglicht die quantitative Abschatzung von Gewebecharakteristika. Zu den messbaren Signalveranderungen tragt nach der IVIM Theorie (le Bihan 1988) neben der extrazellularen Bewegung von Wassermolekulen auch die kapillare Perfusion bei. Es lassen sich so Perfusion und Diffusion nichtinvasiv differenzieren. Wir untersuchten die klinische Anwendung dieser Methode zur Differenzierung metastasensuspekter Leberbefunde. Methode: Eingeschlossen wurden Patienten, welche in einem Zeitraum von 12 Monaten mit der Fragestellung Metastasen zu einer MRT der Leber uberwiesen wurden. Patienten unter Chemotherapie wurden ausgeschlossen. Das Protokoll schlos eine DWI Sequenz (EPI, fatsat, TR/TE 2000/65ms, freie Atmung, 12 Mittelungen, 5 b-Werte (0, 100, 300, 600, 1000s/mm^2)) ein. Signalintensitaten der DWI bei entsprechenden b-Werten wurden durch zwei Radiologen im Konsensus gemessen. Die Messwerte wurden einer biexponentiellen (y=(1-f)*e^(-b*D)+f*e^(-b*D*)) nichtlinearen Regression zugefuhrt. Die Modellparameter f (Perfusionsfraktion), D (Diffusivitat) und D*(Pseudodifussionskoeffizient) wurden einer univariaten ROC und multivariaten logistischen Regressionsanalyse zugefuhrt. Referenzstandard bildeten Histologie oder Verlaufskontrolle >12 Monate. Ergebnis: 41 eingeschlossene Patienten (mittleres Alter 58J) zeigten 95 Herdbefunde (61 maligne, 34 benigne). Gemas univariater ROC Analyse zeigte D die hochste Genauigkeit zur Differenzierung von benignen und malignen Herdbefunden (ROC 0,706, P<0,05). Die Kombination von f und D zeigte die hochste ROC (0,851, P<0,05). Schlussfolgerung: Die Perfusion und Diffusion berucksichtigende Abschatzung nichtkoharenter Bewegung unter Verwendung eines Mehrkompartmentmodells unter klinischen Bedingungen ergab eine hohe diagnostische Genauigkeit zur Differenzierung zwischen metastasenverdachtigen Befunden. Keywords: Leber, DWI, IVIM, Primovist, Metastasen Korrespondierender Autor: Baltzer PA Universitatsklinikum Jena, IDIR, Erlanger Allee 101, 07740 Jena E-Mail: pascal.baltzer@med.uni-jena.de

Asymmetrisch segmentale Anreicherungen in der MR-Mammographie (MRM). Histopathologisches Korrelat

Ziele: Die Detektion schon fruher, nicht invasiver Tumorformen gilt als Vorraussetzung fur eine effiziente Therapie von Brustkrebs. Asymmetrisch segmentale Anreicherungen gelten als ein Hinweis auf ein duktales Carcinoma in situ (DCIS) in der MR-Mammographie. Die vorliegende Untersuchung wurde durchgefuhrt um mittels histopathologischer Korrelation die diagnostische Wertigkeit derselben zu evaluieren. Methode: 316 Patientinnen mit nach einer MR-Mammographie (1,5 T, Bolusinjektion von 0,1 mmol/kg Gd-DTPA mit 3ml/s, 7 Postkontrastmessungen in einminutigem Intervall) operativ gesicherten Herdbefunden wurden prospektiv durch zwei geblindete, in der MRM erfahrene Radiologen analysiert. Asymmetrisch segmental auf die Mamille hin konfigurierte Anreicherungsmuster wurden dabei als verdachtig gewertet. Die gefundenen Lasionen wurden anschliesend mit klinischen und pathologischen Angaben korreliert. Ergebnis: Die Korrelation mit der Pathologie ergab 46 segmentale Anreicherungen, davon 38 mit und und 8 ohne Assoziation mit soliden Herdbefunden. Von ersterer Gruppe zeigten 34 Befunde (89,5%) eine Assoziation mit Malignitat (25 invasiv duktal, 4 invasiv lobular, 3 Tumoren vom Mischtyp und 2 reine DCIS, es fanden sich in 15 Fallen DCIS-Anteile in der Umgebung invasiver Tumoren), die ubrigen Befunde (4; 11,5%) ergaben eine benigne Histologie (2 Fibroadenome, einmal Papillome sowie einmal proliferative mastopathische Veranderungen). 4 (50%) der segmentalen Anreicherungen ohne Herdassoziation zeigten ein DCIS, 4 (50%) benigne Befunde (in 3 Fallen proliferative mastopathische Veranderungen, eine fokale Mastitis). Die gesamte Sensitivitat betrug 82,6% bezuglich Malignitat, fur DCIS oder DCIS Komponenten invasiver Tumoren 45,7%. Schlussfolgerung: Die gefundenen Ergebnisse zeigen eine deutliche Assoziation von segmentalen Anreicherungen mit Malignitat auf der einen und DCIS auf der anderen Seite. Zur Ermittelung der Spezifitat sollten erganzend nichtinvasive Komponenten invasiver Tumoren und DCIS in Fallen ohne segmentales Anreicherungensmuster evaluiert werden. Korrespondierender Autor: Baltzer PA Institut fur Diagnostische und Interventionelle Radiologie/Uniklinik Jena, Gynakologische Radiologie, Erlanger Allee 101, 07740 Jena E-Mail: pascal.baltzer@med.uni-jena.de