E. Grabbe

Classification of hypervascularized lesions in CE MR imaging of the breast

Abstract. The purpose of this paper is to define and evaluate a classification category for contrast-enhanced (CE) MR imaging of the breast based on the BI-RADS mammographic categories of the American College of Radiology. Using five evaluation criteria for MR findings (initial signal increase, postinitial signal behavior, shape, border, and contrast material distribution within enhancing tumors) 522 patients (1031 breasts) were analyzed. Scores were given from 0 to 8 points and classified into five categories (group I: 0 points, negative; group II: 1–2 points, benign; group III: 3 points, probably benign; group IV: 4–5 points, suspicious abnormality; group V: 6–8 points, highly suspicious for malignancy) to 265 focal hypervascularized breast lesions in 244 breasts (patient group A). These findings were correlated with histology or follow-up. Additionally, this classification was correlated to the contrast medium uptake within the parenchyma of the remaining 787 breasts without any focal lesion (patient group B). Two hundred sixty-five hypervascularized lesions in 238 patients (244 breasts, patient group A) were classified into group I: 0%; group II: 27.3%; group III: 22.3%; group IV: 18.6%; and group V: 31.8%. Histology revealed 115 benign and 134 malignant tumors in these groups. Sixteen benign lesions were controlled by follow-up. Sensitivity for the detection of malignancy using the presented multifactorial MRM classification was 92%, and specificity was 92%. Excluding cases of ductal carcinoma in situ specificity increased to 95%. Seven hundred eighty-seven breasts without any focal hypervascularized lesion (patient group B) were classified into groups I or II. Follow-up (n=771) or histology (n=14) confirmed the diagnosis in 785 of these breasts. Histopathology revealed, however, malignant tumors in the remaining two cases. The classification of lesions based on a multifactorial analysis is very helpful in the interpretation of CE MRI of the breast. The evaluation of all diagnostic imaging modalities, however, is essential in determining the correct diagnosis and/or in deciding on the appropriate therapeutic procedure.

CT OF RETAINED SURGICAL SPONGES (TEXTILOMAS): PITFALLS IN DETECTION AND EVALUATION

PURPOSE Our goal was to demonstrate possible pitfalls in the CT diagnosis of retained surgical sponges (textilomas) and to evaluate the impact of gas bubbles inside a textiloma. METHOD Thirteen patients with textilomas were investigated with CT 3 weeks to 8 years after surgery. Twelve of the 13 textilomas were removed within 3 weeks after the first CT examination. Eight samples of surgical sponges were placed in a water bath for 6 months. Serial CT was performed to document the presence and persistence of gas bubbles. RESULTS The radiopaque marker inside the textiloma was seen in nine patients but did not lead to the diagnosis in all patients. In seven patients gas bubbles were found inside the textiloma with a typical pattern. None of these patients had an abscess formation. In vitro studies demonstrated gas bubbles in all surgical sponges scanned 1 h afterward. The number of gas bubbles was not significantly reduced after 6 months. CONCLUSION The variable appearance of retained surgical sponges can lead to diagnostic misinterpretations. If present, typical spongiform pattern with gas bubbles is the most specific sign for the detection of textilomas but does not indicate an abscess formation.

Comparative study in patients with microcalcifications: full-field digital mammography vs screen-film mammography

Abstract. The goal of this prospective study was to compare a full-field digital mammography system (FFDM) to a conventional screen-film mammography system (SFM) for the detection and characterization of microcalcifications. Fifty-five patients with 57 isolated microcalcification clusters were examined using a FFDM system (Senographe 2000D, GE Medical Systems, Milwaukee, Wis.) and a SFM system (Senographe DMR, GE Medical Systems, Milwaukee, Wis.). A conventional screen-film mammogram and a digital contact mammogram were obtained of each cluster. The image quality and the number of calcification particles were evaluated, and a characterization (BI-RADS 1–5) of microcalcifications was given by four experienced readers. Histopathology revealed 16 benign lesions (sclerosing adenosis, dysplasia, hamartoma, radial scar) in 15 patients and 21 malignant tumors (in situ carcinoma, invasive carcinoma) in 20 patients. Twenty patients had benign changes verified by long-term follow-up. Image quality of FFDM was assessed as superior to SFM in more than 50% of the cases. The FFDM showed more calcifications in 41% of all cases. Sensitivity and specificity for FFDM vs SFM were 95.2 vs 91.9% and 41.4 vs 39.3%, respectively. Moreover, FFDM demonstrated a higher diagnostic accuracy (deviation: 0.86 BI-RADS steps) compared with FSM (deviation 0.93 BI-RADS steps). The FFDM system with a 100-µm pixel size provides better image quality than SFM in patients with mammographic microcalcifications. The FFDM has a higher sensitivity and a higher reliability in characterizing microcalcifications.

Applications and literature review of the BI-RADS classification.

The Breast Imaging Reporting and Data System (BI-RADS) of the American College of Radiology (ACR) is a tool created to reduce variability in the terminology used in mammographic reports. An illustration of mammographic examples from our institution interpreted according to the BI-RADS lexicon of the American College of Radiology (ACR) is presented. A literature review concerning the usefulness and limitations of the BI-RADS lexicon is given.

Magnetic resonance guided localization and biopsy of suspicious breast lesions.

Contrast-enhanced magnetic resonance imaging (MRI) is being used increasingly as a complementary diagnostic modality in breast imaging of preselected patients. The exclusion of multicentricity before surgery and the differentiation between a scar and a carcinoma are well-accepted indications of this method. Problems result when suspicious lesions found with MRI cannot be visualized with mammography or ultrasonography. In these cases, MRI-based guidance systems are needed to guide needle biopsy or allow localization of the lesion before surgery. At our institution. 167 MR-guided interventions (35 percutaneous biopsies and 132 preoperative localizations) have been performed with the use of different types of add-on devices during the past 3 years. Percutaneous biopsy (31 fine needle aspiration and four core biopsies) revealed 24 benign and 8 malignant lesions, 3 biopsies were insufficient. Histologic examination after MR-guided wire localization showed benign findings in 68 lesions (52%) and malignancy in 64 lesions (48%). Technical aspects, experiences, advantages, and disadvantages of our system as well as those of other devices are reported and discussed. MR-compatible equipment for interventions of the breast is demonstrated. In conclusion, we perform MR-guided interventions of the breast routinely in indicated cases at a rate of −3–5% for all patients undergoing diagnostic contrast-enhanced MRI of the breast.

Prognostic value of contrast-enhanced MR mammography in patients with breast cancer.

Abstract The objective of this study was to evaluate the prognostic value of contrast-enhanced MR mammography in patients with breast cancer. A total of 190 patients with breast cancer (37 noninvasive carcinomas, 153 invasive carcinomas) underwent dynamic contrast-enhanced MR mammography preoperatively. Using 1.5-T unit, T1-weighted sequences (2D FLASH) were obtained repeatedly one time before and five times after IV administration of 0.1 mmol gadopentetate-dimeglumine per kilogram body weight. The findings on MR imaging were correlated with histopathologically defined prognostic factors (histological type, tumor size, tumor grading, metastasis in lymph nodes). In addition, immunohistochemically defined prognostic factors (c-erbB-1,c-erbB-2, p53, Ki-67) were correlated with the signal increase on MR mammogram in 40 patients. There was no significant correlation between the findings on MR mammography and the histopathological type of carcinoma, the grading, and the lymphonodular status. Noninvasive carcinomas showed a higher rate of moderate (38 %) or low (27 %) enhancement on MR imaging than invasive carcinomas (6 and 3 %). The results on MR mammography and the results of immunohistochemical stainings did not correlate significantly. Noninvasive carcinomas showed significantly lower enhancement than invasive carcinomas. However, the signal behavior of contrast-enhanced MR mammography is not related to established histopathological prognostic parameters as subtyping, grading, nodal status, and the expression of certain oncogenes/tumor suppressor genes.

MRI of the breast in patients with metastatic disease of unknown primary

Abstract. The objective of this study was to assess the value of contrast-enhanced dynamic breast imaging in patients with carcinoma of unknown primary (CUP). Fourteen patients presenting with metastatic disease compatible with breast cancer (axillary lymph node metastasis: n = 6; supraclavicular lymph node metastasis: n = 1; bone metastasis: n = 3; liver metastasis: n = 3; lung metastasis: n = 1), who had no evidence of tumor in X-ray mammograms and ultrasound, underwent bilateral dynamic breast MR imaging. Suspicious lesions were localized preoperatively using a stereotactic device for MR-guided localization procedures. Magnetic resonance imaging revealed suspicious lesions in 9 of 14 patients. Histopathology revealed invasive carcinoma of the breast in 6 of these patients. Two enhancing lesions were fibroadenomas; one proved to be sclerosing adenosis. In 5 patients MR imaging showed no abnormality. Follow-ups performed up to 1 year after initial treatment revealed no breast cancers in these 5 patients. In patients with metastatic disease of unknown primary, MRI of the breast depicts the primary in a considerable number of cases with normal conventional evaluation.

3D virtual endoscopy of the upper airway: optimization of the scan parameters in a cadaver phantom and clinical assessment.

Our goal was to evaluate the influence of the scan parameters on the 3D virtual endoscopy of the larynx and trachea and the clinical assessment. Helical CT (HiSpeed Advantage; GE, Milwaukee, WI, U.S.A.) of a cadaver phantom was performed with increased collimation (1-10 mm) and pitch (0.5-3). Seventy-two patients with complaints of the upper airways were investigated by virtual endoscopy and their results were compared with the findings of regular endoscopy. Best correlation between virtual endoscopy and anatomical findings, diagnostic quality of the axial slices, and useful longitudinal coverage of the examination were obtained with a collimation of 3 mm and a pitch of 1.5. Space-occupying tumors and stenosis were detected correctly, but the mucous membrane could not be visualized. 3D virtual endoscopy proved to be a valuable method for displaying anatomical structures. For an optimal protocol, a collimation of 3 mm with a pitch of 1.5 is recommended.

MRI in the evaluation of müllerian duct anomalies.

OBJECTIVE Müllerian duct anomalies (MDAs) result from nondevelopment or nonfusion of the müllerian ducts and occur in 1-5% of women. Accurate diagnosis of the various subtypes is of great importance as MDAs are frequently associated with a broad variety of clinical symptoms. Recently, evidence arose that MRI might play a major role in diagnosis of MDAs. We present four cases of diverse subtypes of MDAs and the corresponding MRI findings. MATERIALS AND METHODS Patients (n = 4) with clinical suspicion of MDAs were examined with MRI. Coronal and transaxial T1- and T2-weighted images were acquired. Diagnosis was made and patients were grouped according to the American Fertility Societys classification. Patients underwent laparoscopy or laparotomy in order to confirm the diagnosis. RESULTS MRI revealed MDAs in all patients. In detail, one patient was diagnosed with hypoplastic uterus, one with unicornuate uterus with a noncommunicating rudimentary horn, one with bicornuate uterus bicollis with a double vagina and one with septate uterus. MRI diagnosis was correct in all cases, as confirmed by subsequent surgical intervention. CONCLUSION MRI is a valuable tool in diagnosis of MDA subtypes. Its use will help to spare patients mutilating surgery and to prevent pregnancy-associated complications.

Magnification mammography: a comparison of full-field digital mammography and screen-film mammography for the detection of simulated small masses and microcalcifications

Abstract. The objective of this study was a comparison of a full-field digital mammography (FFDM) system and a conventional screen-film mammography (SFM) system with respect to the detectability of simulated small masses and microcalcifications in the magnification mode. All images were obtained using 1.8 times magnification. The FFDM images were obtained at radiation dose levels of 1.39, 1.0, 0.7, 0.49 and 0.24 times that of the SFM images. A contrast-detail phantom was used to compare the detection of simulated lesions using a four alternative forced-choice reader study with three readers. The correct observation ratio (COR) was calculated as the fraction of correctly identified lesions to the total number of simulated lesions. Soft-copy reading was performed for all digital images. Direct magnification images acquired with the digital system showed a lower object contrast threshold than those acquired with the conventional system. For equal radiation dose, the digital system provided a significantly increased COR (0.95) compared with the screen-film system (0.82). For simulated microcalcifications, the corresponding difference was 0.90 to 0.72. The digital system allowed equal detection to screen-film at 40% of the radiation dose used for screen film. Digital magnification images are superior to screen-film magnification images for the detection of simulated small masses and microcalcifications even at a lower radiation dose.