Search

Clinical/methodical Issue: Magnetic resonance imaging (MRI) of the breast is an indispensable tool in breast imaging for many indications. Several functional parameters with MRI and positron emission tomography (PET) have been assessed for imaging of breast tumors and their combined application is defined as multiparametric imaging. Available data suggest that multiparametric imaging using different functional MRI and PET parameters can provide detailed information about the hallmarks of cancer and may provide additional specificity., Standard Radiological Methods: Multiparametric and molecular imaging of the breast comprises established MRI parameters, such as dynamic contrast-enhanced MRI, diffusion-weighted imaging (DWI), MR proton spectroscopy ((1)H-MRSI) as well as combinations of radiological and MRI techniques (e. g. PET/CT and PET/MRI) using radiotracers, such as fluorodeoxyglucose (FDG)., Methodical Innovations: Multiparametric and molecular imaging of the breast can be performed at different field-strengths (range 1.5-7 T). Emerging parameters comprise novel promising techniques, such as sodium imaging ((23)Na MRI), phosphorus spectroscopy ((31)P-MRSI), chemical exchange saturation transfer (CEST) imaging, blood oxygen level-dependent (BOLD) and hyperpolarized MRI as well as various specific radiotracers., Achievements: Multiparametric and molecular imaging has multiple applications in breast imaging. Multiparametric and molecular imaging of the breast is an evolving field that will enable improved detection, characterization, staging and monitoring for personalized medicine in breast cancer.

Purpose: To intra-individually compare the diagnostic image quality of Dixon and spectral fat suppression at 3 T., Methods: Fifty consecutive patients (mean age 55.1 years) undergoing 3 T breast MRI were recruited for this prospective study. The image protocol included pre-contrast and delayed post-contrast spectral and Dixon fat-suppressed T1w series. Two independent blinded readers compared spectral and Dixon fat-suppressed series by evaluating six ordinal (1 worst to 5 best) image quality criteria (image quality, delineation of anatomical structures, fat suppression in the breast and axilla, lesion delineation and internal enhancement). Breast density and size were assessed. Data analysis included Spearman's rank correlation coefficient and visual grading characteristics (VGC) analysis., Results: Four examinations were excluded; 48 examinations in 46 patients were evaluated. In VGC analysis, the Dixon technique was superior regarding image quality criteria analysed (P < 0.01). Smaller breast size and lower breast density were significantly (P < 0.01) correlated with impaired spectral fat suppression quality. No such correlation was identified for the Dixon technique, which showed reconstruction-based water-fat mixups leading to insufficient image quality in 20.8%., Conclusions: The Dixon technique outperformed spectral fat suppression in all evaluated criteria (P < 0.01). Non-diagnostic examinations can be avoided by fat and water image reconstruction. The superior image quality of the Dixon technique can improve breast MRI interpretation., Key Points: Optimal fat suppression quality is necessary for optimal image interpretation. Superior fat suppression quality is achieved using the Dixon technique. Lesion margin and internal enhancement evaluation improves using the Dixon technique. Superior image quality of the Dixon technique improves breast MRI interpretation.

Objective: The objective of our study was to evaluate the clinical application of bilateral high spatial and temporal resolution dynamic contrast-enhanced magnetic resonance imaging (HR DCE-MRI) of the breast at 7 T., Methods: Following institutional review board approval 23 patients with a breast lesion (BIRADS 0, 4-5) were included in our prospective study. All patients underwent bilateral HR DCE-MRI of the breast at 7 T (spatial resolution of 0.7 mm(3) voxel size, temporal resolution of 14 s). Two experienced readers (r1, r2) and one less experienced reader (r3) independently assessed lesions according to BI-RADS®. Image quality, lesion conspicuity and artefacts were graded from 1 to 5. Sensitivity, specificity and diagnostic accuracy were assessed using histopathology as the standard of reference., Results: HR DCE-MRI at 7 T revealed 29 lesions in 23 patients (sensitivity 100 % (19/19); specificity of 90 % (9/10)) resulting in a diagnostic accuracy of 96.6 % (28/29) with an AUC of 0.95. Overall image quality was excellent in the majority of cases (27/29) and examinations were not hampered by artefacts. There was excellent inter-reader agreement for diagnosis and image quality parameters (κ = 0.89-1)., Conclusion: Bilateral HR DCE-MRI of the breast at 7 T is feasible with excellent image quality in clinical practice and allows accurate breast cancer diagnosis., Key Points: • Dynamic contrast-enhanced 7-T MRI is being developed in several centres. • Bilateral high resolution DCE-MRI of the breast at 7 T is clinically applicable. • 7-T HR DCE-MRI of the breast provides excellent image quality. • 7-T HR DCE-MRI should detect breast cancer with high diagnostic accuracy.

Clinical/methodical Issue: The aim of molecular imaging is to visualize and quantify biological, physiological and pathological processes at cellular and molecular levels. Molecular imaging using various techniques has recently become established in breast imaging., Standard Radiological Methods: Currently molecular imaging techniques comprise multiparametric magnetic resonance imaging (MRI) using dynamic contrast-enhanced MRI (DCE-MRI), diffusion-weighted imaging (DWI), proton MR spectroscopy ((1)H-MRSI), nuclear imaging by breast-specific gamma imaging (BSGI), positron emission tomography (PET) and positron emission mammography (PEM) and combinations of techniques (e.g. PET-CT and multiparametric PET-MRI)., Methodical Innovations: Recently, novel techniques for molecular imaging of breast tumors, such as sodium imaging ((23)Na-MRI), phosphorus spectroscopy ((31)P-MRSI) and hyperpolarized MRI as well as specific radiotracers have been developed and are currently under investigation., Practical Recommendations: It can be expected that molecular imaging of breast tumors will enable a simultaneous assessment of the multiple metabolic and molecular processes involved in cancer development and thus an improved detection, characterization, staging and monitoring of response to treatment will become possible.

Objective: To develop and assess a combined reading for contrast-enhanced magnetic resonance (CE-MRI) and diffusion weighted imaging (DWI) adapted to the BI-RADS for multiparametric MRI of the breast at 3 T., Methods: A total of 247 patients with histopathologically verified breast lesions were included in this IRB-approved prospective study. All patients underwent CE-MR and DWI at 3 T. MRIs were classified according to BI-RADS and assessed for apparent diffusion coefficient (ADC) values. A reading method that adapted ADC thresholds to the assigned BI-RADS classification was developed. Sensitivity, specificity, diagnostic accuracy and the area under the curve were calculated. BI-RADS-adapted reading was compared with previously published reading methods in the same population. Inter- and intra-reader variability was assessed., Results: Sensitivity of BI-RADS-adapted reading was not different from the high sensitivity of CE-MRI (P = 0.4). BI-RADS-adapted reading maximised specificity (89.4 %), which was significantly higher compared with CE-MRI (P < 0.001). Previous reading methods did not perform as well as the BI-RADS method except for a logistic regression model. BI-RADS-adapted reading was more sensitive in non-mass-like enhancements (NMLE) and was more robust to inter- and intra-reader variability., Conclusion: Multiparametric 3-T MRI of the breast using a BI-RADS-adapted reading is fast, simple to use and significantly improves the diagnostic accuracy of breast MRI. KEYPOINTS : • Multiparametric breast 3-T MRI with BI-RADS-adapted reading improves diagnostic accuracy. • BI-RADS-adapted reading of CE-MRI and DWI is based on established reporting guidelines. • BI-RADS-adapted reading is fast and easy to use in routine clinical practice. • BI-RADS-adapted reading is robust to intra- and inter-reader variability.

Objective: To identify which breast lesion descriptors in the ACR BI-RADS® MRI lexicon are most strongly associated with the diagnosis of breast cancer when performing breast MR imaging at 3 T., Methods: 150 patients underwent breast MR imaging at 3 T. Lesion size, morphology and enhancement kinetics were assessed according to the BI-RADS® classification. Sensitivity, specificity and diagnostic accuracy were assessed. The effects of the BI-RADS® descriptors on sensitivity and specificity were evaluated. Data were analysed using logistic regression. Histopathological diagnoses were used as the standard of reference., Results: The sensitivity, specificity and diagnostic accuracy of breast MRI at 3 T was 99%, 81% and 93%, respectively. In univariate analysis, the final diagnosis of malignancy was positively associated with irregular shape (p < 0.001), irregular margin (p < 0.001), heterogeneous enhancement (p < 0.001), Type 3 enhancement kinetics (p = 0.02), increasing patient age (p = 0.02) and larger lesion size (p < 0.001). In multivariate analysis, significant associations with malignancy remained for mass shape (p = 0.06), mass margin (p < 0.001), internal enhancement pattern (p = 0.03) and Type 3 enhancement kinetics (p = 0.06)., Conclusion: The ACR BI-RADS® breast lesion descriptors that are mostly strongly associated with breast cancer in breast MR imaging at 3 T are lesion shape, lesion margin, internal enhancement pattern and Type 3 enhancement kinetics., Key Points: • 3 Tesla breast MRI allows an accurate diagnosis of breast cancer • The BI-RADS® descriptors help provide a confident diagnosis • The shape, margin, enhancement pattern and kinetics are the most important features • An irregular shape and margin, heterogeneous enhancement and type-3 kinetics indicate malignancy.

In recent years magnetic resonance imaging (MRI) has been increasingly established in the diagnosis of prostate cancer in addition to transrectal ultrasonography (TRUS). The use of T2-weighted imaging allows an exact delineation of the zonal anatomy of the prostate and its surrounding structures. Other MR imaging tools, such as dynamic contrast-enhanced T1-weighted imaging or diffusion-weighted imaging allow an inference of the biochemical characteristics (multiparametric MRI). Prostate cancer, which could only be diagnosed using MR imaging or lesions suspected as being prostate cancer, which are localized in the anterior aspect of the prostate and were missed with repetitive TRUS biopsy, need to undergo MR guided biopsy. Recent studies have shown a good correlation between MR imaging and histopathology of specimens collected by MR-guided biopsy. Improved lesion targeting is therefore possible with MR-guided biopsy. So far data suggest that MR-guided biopsy of the prostate is a promising alternative diagnostic tool to TRUS-guided biopsy.

Prostate cancer is biologically and clinically a heterogeneous disease which makes imaging evaluation challenging. Magnetic resonance imaging (MRI) has considerable potential to improve prostate cancer detection and characterization. Until recently morphologic MRI has not been routinely incorporated into clinical care because of its limitation to detect, localize and characterize prostate cancer. Performing prostate gland MRI using functional techniques has the potential to provide unique information regarding tumor behavior, including treatment response. In order for multiparametric MRI data to have an impact on patient management, the collected data need to be relayed to clinicians in a standardized way for image construction, analysis and interpretation. This will ensure that patients are treated effectively and in the most appropriate way. Scoring systems similar to those employed successfully for breast imaging need to be developed.

Women with an elevated risk for breast cancer require intensified screening beginning at an early age. Such high risk screening differs considerably from screening in the general population. After an expert has evaluated the exact risk a breast MRI examination should be offered at least once a year and beginning latest at the age of 30 depending on the patients risk category. Complementary mammograms should not be performed before the age of 35. An additional ultrasound examination is no longer recommended. To ensure a high sensitivity and specificity high risk screening should be performed only at a nationally or regionally approved and audited service. Adequate knowledge about the phenotypical characteristics of familial breast cancer is essential. Besides the common malignant phenotypes, benign morphologies (round or oval shape and smooth margins) as well as a low prevalence of calcifications have been described. Using MRI benign contrast media kinetics as well as non-solid lesions with focal, regional and segmental enhancement can often be visualized.

Our objective was to assess the ability of MR imaging in the detection of the normal appendix, and to describe the MR appearance of the normal appendix. There were 15 healthy volunteers (11 girls, 4 boys; mean age 12.3 years) who underwent MR imaging on a 1.0-T unit. The imaging protocol included axial and coronal T2-weighted ultra turbo spin-echo (UTSE)-weighted images, axial T1-weighted turbo spin-echo (TSE) and coronal short tau inversion recovery (STIR)/TSE sequences. Confidence regarding the detection was scored from 1 (high confidence) to 3 (low confidence). Thickness was measured and MR appearance described. Clinical control after 2 weeks revealed no signs or symptoms of acute appendicitis. The normal appendix was seen in 86% on T2/UTSE-weighted images and in 73% on T1/TSE-weighted images and in none on STIR/TSE images. On axial T2/UTSE-weighted images, normal appendix had a hyperintense center and a hypointense wall, and was mostly hypointense on T1/TSE-weighted images, with a mean thickness of 4.5 mm. Magnetic resonance imaging seems to be an accurate method for the assessment of the normal appendix in children; thus, MR imaging might be an alternative to CT if US examinations are inconclusive.

Objective: The aim of our study was to evaluate prospectively the grades and patterns of gadopentetate-enhanced MR imaging in the radiocarpal joints of healthy subjects after IV contrast administration., Subjects and Methods: The study included 18 healthy subjects (nine men, nine women; age range, 24-34 years; mean age, 30.8 years). We obtained coronal T1-weighted spin-echo images with fat suppression before and after IV administration of gadopentetate dimeglumine and additional axial T1-weighted spin-echo images after contrast administration. Patterns of signal-intensity enhancement in and around the radiocarpal joints were evaluated qualitatively and quantitatively., Results: In eight (44.4%) of 18 healthy subjects, enhancement of the radiocarpal joints was seen and exclusively located in the region of the prestyloid recess. Enhancement patterns were bandlike in three (16.7%) of 18 healthy subjects, homogeneous in another three (16.7%) of 18, and nodular in two (11.1%) of 18., Conclusion: After IV administration of gadopentetate, signal-intensity enhancement in the radiocarpal joint is frequently seen in healthy subjects and is not predictive of inflammatory joint disease. If contrast enhancement is present, three distinct patterns are usually revealed, all invariably located in the region of the prestyloid recess.

Ductal carcinoma in situ (DCIS) represents a heterogenous group of lesions nowadays most commonly detected by mammography. The biological behaviour of ductal carcinoma in situ ranges from clinically occult, indolent, essentially benign lesions to precursors of invasive carcinoma. This work gives a review on the natural history of this disorder, and focuses on its imaging features. Stress is laid on the pivotal role of mammography in the management of ductal carcinoma in situ. The recent literature is reviewed.

Contrast-enhanced MRI of the breast has proved to be a valuable tool in the detection and work-up of breast lesions. Most of these lesions are small and not visible by other imaging modalities, such as mammography or US. Thus, only MR-guided preoperative localization techniques or MR-guided percutaneous biopsy can provide a histologic work-up of such lesions. MR-guided preoperative localization seems to be a well-established procedure. However, MR-guided biopsy is still problematic. Although prototypical biopsy systems have been developed, considerable progress is still required. Problems exist with MR-guided biopsy due to severe needle artifacts and tissue shift during the intervention. Thus, needle biopsy currently is not recommended for lesions smaller than 10 mm. This work reviews current techniques for MR-guided preoperative localization and percutaneous biopsy in breast lesions. The diagnostic accuracy achievable with these techniques will be discussed, as well as the potential for new research opportunities and directions. J. Magn. Reson. Imaging 2001;13:903-911., (Copyright 2001 Wiley-Liss, Inc.)

This study assessed several proposed imaging strategies and analytic methods based on gadopentetate-enhanced MRI to differentiate benign from malignant breast tumors in a blinded experimental animal study. Steady-state dynamic MRI and first-pass imaging, performed with either T(1)- or T*(2)- weighted sequences, were compared. Semiquantitative and quantitative analysis methods, based on empirical measures of the data or physiological models, were subsequently applied to the imaging datasets. Comparative measures provided pathologic distinction of benign from malignant tumors, tumor grading, and histologic determination of microvascular density. Of the eight tested methods, only one, an estimate of first-pass perfusion using T *(2)-weighted imaging, showed an almost significant (P = 0.05) difference between benign and malignant tumors and correlated almost significantly (r =.3, P = 0.06) with the tumor grade. All other tests, performed either with steady-state imaging or with T(1)-weighted first-pass imaging, failed to differentiate benign from malignant tumors. In addition, they yielded poor correlations with tumor grade and microvascular density.

Objective: Magnetic resonance imaging enhanced with macromolecular contrast medium was used to monitor effects of angiogenesis inhibition on tumor microvascular permeability and ascites volume in an athymic rat model of human ovarian cancer., Study Design: Groups of 6 athymic rats implanted intraperitoneally with SKOV-3, a human ovarian cancer cell line, were treated through a 14-day course with antibody to vascular endothelial growth factor or with saline solution for control animals. Dynamic magnetic resonance imaging was performed with a 92,000-d contrast agent, albumin-(gadolinium-diethylenetriaminepentaacetic acid)(30). Vascular permeability was estimated from dynamic enhancement data that were analyzed with a unidirectional 2-compartment kinetic model., Results: Animals treated with vascular endothelial growth factor antibody accumulated significantly smaller volumes of peritoneal ascites (P <.05) and showed significantly lower magnetic resonance imaging-assayed tumor microvascular permeabilities (P <.05) than did control animals., Conclusion: Magnetic resonance imaging enhanced with a macromolecular contrast agent in an athymic rat model of human ovarian cancer treated with anti-vascular endothelial growth factor antibody can be used to measure a reduction in tumor microvascular permeability, corresponding to a reduction in ascites production.

Objective: Interstitial pregnancy occurs in 2-4% of ectopic pregnancies and is defined as implantation of the trophoblast in the interstitial part of the tuba uterina. Therefore the term intramural pregnancy can also be found in the literature. In 20% of the cases that progress beyond 12 weeks of amenorrhea a potentially life-threatening rupture of the uterus occurs, leading to a maternal mortality rate of 2.5%. According to the literature until a few years ago diagnosis was mainly made intraoperatively, and resulted in cornual resection or hysterectomy per laparotomy. Better methods of diagnosis and treatment of interstitial pregnancy can help to decrease morbidity and mortality associated with this condition., Patients: We describe two cases of interstitial pregnancies that were eventually diagnosed and also monitored by magnetic resonance imaging (MRI) after systemic methotrexate treatment. Both patients were uniparous and experienced their second spontaneous pregnancy., Methods: Treatment consisted of four doses (50 mg/m2 body surface area) of systemic intramuscular methotrexate alternating with four doses (6 mg) of intramuscular folic acid. When beta-hCG levels were undetectable, MRI results were compared with pre-therapeutic MRI findings., Results: In patients A and B, beta-hCG levels were undetectable 64 and 88 days after initiation of methotrexate treatment, while magnetic resonance imaging revealed nearly equally persisting interstitial pregnancies. They initially presented as hyperintense lesions with hypointense zones and changed into a hypointense lesion with a central hyperintense area for patient A, and a completely hyperintense lesion for patient B at the time of negative beta-hCG levels in follow-up MRI., Conclusion: Systemic methotrexate treatment with an intramuscular regimen is effective in the treatment of interstitial pregnancy. MRI has the ability of correct tissue differentiation and objective three-dimensional measuring of interstitial pregnancy. We therefore propose this imaging modality as a valuable tool for monitoring systemic methotrexate treatment of interstitial pregnancy that should be used additionally to beta-hCG clearance curves.

Objective: Our study was undertaken to develop diagnostic rules and to assess the reproducibility of dynamic and morphologic parameters for the characterization of suspicious breast lesions using dynamic high-spatial-resolution MR imaging., Materials and Methods: Fifty-seven patients with suspicious mammographic or palpable findings underwent preoperative contrast-enhanced MR imaging of the breast using a three-time-point method of acquisition. Each lesion was prospectively analyzed by two independent radiologists for morphologic and visual dynamic enhancement characteristics. A classification and regression tree was used to examine the optimal order, cutoff points, and combination of imaging parameters to build a diagnostic rule separating benign from malignant lesions using histopathology findings as the standard of reference. Kappa statistics were used to determine observer variability., Results: Among 23 benign and 34 malignant lesions (12 invasive, three ductal carcinoma in situ, and 19 mixed cancer), margin morphology (p = 0.001) and enhancement pattern (p = 0.001) were the most significant MR imaging findings for lesion characterization. Focal mass lesions were classified as malignant when spiculated margins or both the washout enhancement pattern and "nonsmooth" margins were present. Interobserver agreement was almost perfect for washout pattern and substantial for margin assessment. In the limited population tested retrospectively, the diagnostic rule yielded a sensitivity and positive predictive value of 97% each and a specificity and negative predictive value of 96% each., Conclusion: The washout enhancement pattern combined with lesion margin assessment on dynamic contrast-enhanced high-resolution MR imaging of the breast allows reproducible lesion characterization and may be a highly specific diagnostic tool.

Contrast-enhanced magnetic resonance (MR) imaging is increasingly used as a complementary diagnostic modality in breast imaging. The sensitivity of MR imaging of the breast for malignancy has consistently been reported to be excellent. The specificity has been rather variable. Study methods and imaging techniques are not standardized and there is still a great deal of uncertainty about MR imaging's place in clinical practice. Nevertheless, radiologists should be familiar with the current technique and the varying MR appearance of breast tumors to improve the accuracy of this method. This paper reviews the techniques for breast MR imaging, the pathopysiologic basis of contrast enhancement in breast tumors, and the current knowledge about detection and differentiation of breast tumors. In addition, future directions for breast MR imaging are discussed.

The aims of this study were to characterize certain physicochemical, pharmacokinetic, and enhancement properties of a new macromolecular contrast agent, carboxymethyl hydroxyethyl starch-(Gd-DO3A)(35) [CMHES-(Gd-DO3A)(35)], consisting of a polysaccharide backbone covalently derivatized with multiple macrocyclic chelating groups for gadolinium. CMHES-(Gd-DO3A)(35) has an average molecular weight of 72 kD and a plasma half-time of 8.4 hours. T1 and T2 relaxivities are 14.1 +/- 0.1 L mmol(-1) * sec(-1) and 17.8 +/- 0.9 L mmol(-1) * sec(-1), respectively, for each gadolinium ion measured at 39 degrees C and 20 Mhz; this T1 relaxivity is more than 4 times that of gadopentetate. Seven days after intravenous administration only relatively small amounts of gadolinium could be detected in blood or other tissues of rats. The compound was well tolerated in diagnostic dosages by all experimental animals. Magnetic resonance angiography performed within 1 hour of CMHES-(Gd-DO3A)(35) administration showed a near-constant and strong enhancement of blood in arteries and veins. Analysis of dynamic enhancement patterns of experimental tumors (MAT-LyLu prostate cancer implanted in rats) following intravenous CMHES-(Gd-DO3A)(35) administration yielded quantitative estimates of tumor plasma volume and microvessel permeability; the demonstrated hyperpermeability of tumor microvessels was easily distinguished from the absence of measurable microvascular permeability in non-neoplastic soft tissues., (Copyright 2000 Wiley-Liss, Inc.)

Purpose: To differentiate prostate cancers of different histopathologic grades with dynamic gadolinium-enhanced magnetic resonance (MR) imaging. Results with a conventional small-molecular contrast medium (CM) were compared to those with a prototypic macromolecular CM., Materials and Methods: High- and low-grade tumors, sublines of the Dunning R3327 rat prostate cancer line, were subcutaneously implanted into the flanks of 12 male Copenhagen rats. Dynamic contrast material-enhanced MR imaging was performed with small-molecular CM and macromolecular CM at an interval of 1 day. Microvascular permeability, as estimated with the endothelial transfer coefficient, and fractional plasma volume were calculated for each tumor and each CM by means of a two-compartmental, bidirectional kinetic model., Results: Mean endothelial transfer coefficient values for both macromolecular CM and small-molecular CM were significantly different between the two tumor sublines (P = .0004 and P = .01, respectively). For the high- and low-grade tumors, no overlap of values was seen with macromolecular CM, but a broad overlap was seen with small-molecular CM despite a significant difference in mean values., Conclusion: Dynamic contrast-enhanced MR imaging permits differentiation of histopathologic prostatic tumor types. Quantitative microvascular permeability characteristics estimated from macromolecular CM-enhanced data were significantly superior to those derived from small-molecular CM-enhanced data.

MRI can be a valuable technique in patients with silicone-granulomas to screen for cancers which are not visible on mammography and/or sonography.

Purpose: To compare the accuracies of magnetic resonance (MR) imaging and scintimammography in differentiating benign from malignant breast lesions., Materials and Methods: MR imaging was performed in 66 women with 75 lesions during intravenous administration of gadopentetate dimeglumine. Planar and single photon emission computed tomographic (SPECT) scintimammography were performed (with 740 MBq technetium-99m sestamibi administered intravenously) in all 66 patients with 75 lesions and in 64 patients with 73 lesions, respectively. MR imaging and scintimammographic studies were independently evaluated by using signal intensity measurements versus time or focal tracer uptake to differentiate benign from malignant lesions. Histopathologic proof was obtained in 63 lesions. Twelve lesions were monitored with follow-up., Results: MR imaging was false-negative in one and false-positive in nine lesions. Planar scintimammography was false-negative in 10 and false-positive in six lesions. SPECT scintimammography was false-negative in four and false-positive in 10 lesions. Sensitivities and specificities for malignancy were, respectively, 96% and 82% for MR imaging, 62% and 88% for planar scintimammography, and 83% and 80% for SPECT scintimammography., Conclusion: Both MR imaging and scintimammography are useful in the evaluation of breast cancer. MR imaging is more sensitive and as specific as scintimammography.

Purpose: To assess whether a radiomics and machine learning (ML) model combining quantitative parameters and radiomics features extracted from simultaneous multiparametric 18F-FDG PET/MRI can discriminate between benign and malignant breast lesions. Methods: A population of 102 patients with 120 breast lesions (101 malignant and 19 benign) detected on ultrasound and/or mammography was prospectively enrolled. All patients underwent hybrid 18F-FDG PET/MRI for diagnostic purposes. Quantitative parameters were extracted from DCE (MTT, VD, PF), DW (mean ADC of breast lesions and contralateral breast parenchyma), PET (SUVmax, SUVmean, and SUVminimum of breast lesions, as well as SUVmean of the contralateral breast parenchyma), and T2-weighted images. Radiomics features were extracted from DCE, T2-weighted, ADC, and PET images. Different diagnostic models were developed using a fine Gaussian support vector machine algorithm which explored different combinations of quantitative parameters and radiomics features to obtain the highest accuracy in discriminating between benign and malignant breast lesions using fivefold cross-validation. The performance of the best radiomics and ML model was compared with that of expert reader review using McNemar's test. Results: Eight radiomics models were developed. The integrated model combining MTT and ADC with radiomics features extracted from PET and ADC images obtained the highest accuracy for breast cancer diagnosis (AUC 0.983), although its accuracy was not significantly higher than that of expert reader review (AUC 0.868) (p = 0.508). Conclusion: A radiomics and ML model combining quantitative parameters and radiomics features extracted from simultaneous multiparametric 18F-FDG PET/MRI images can accurately discriminate between benign and malignant breast lesions. [ABSTRACT FROM AUTHOR]

Purpose: Risk classification of primary prostate cancer in clinical routine is mainly based on prostate-specific antigen (PSA) levels, Gleason scores from biopsy samples, and tumor-nodes-metastasis (TNM) staging. This study aimed to investigate the diagnostic performance of positron emission tomography/magnetic resonance imaging (PET/MRI) in vivo models for predicting low-vs-high lesion risk (LH) as well as biochemical recurrence (BCR) and overall patient risk (OPR) with machine learning. Methods: Fifty-two patients who underwent multi-parametric dual-tracer [18F]FMC and [68Ga]Ga-PSMA-11 PET/MRI as well as radical prostatectomy between 2014 and 2015 were included as part of a single-center pilot to a randomized prospective trial (NCT02659527). Radiomics in combination with ensemble machine learning was applied including the [68Ga]Ga-PSMA-11 PET, the apparent diffusion coefficient, and the transverse relaxation time-weighted MRI scans of each patient to establish a low-vs-high risk lesion prediction model (MLH). Furthermore, MBCR and MOPR predictive model schemes were built by combining MLH, PSA, and clinical stage values of patients. Performance evaluation of the established models was performed with 1000-fold Monte Carlo (MC) cross-validation. Results were additionally compared to conventional [68Ga]Ga-PSMA-11 standardized uptake value (SUV) analyses. Results: The area under the receiver operator characteristic curve (AUC) of the MLH model (0.86) was higher than the AUC of the [68Ga]Ga-PSMA-11 SUVmax analysis (0.80). MC cross-validation revealed 89% and 91% accuracies with 0.90 and 0.94 AUCs for the MBCR and MOPR models respectively, while standard routine analysis based on PSA, biopsy Gleason score, and TNM staging resulted in 69% and 70% accuracies to predict BCR and OPR respectively. Conclusion: Our results demonstrate the potential to enhance risk classification in primary prostate cancer patients built on PET/MRI radiomics and machine learning without biopsy sampling. [ABSTRACT FROM AUTHOR]