Prospective study of breast MRI in BRCA1 and BRCA2 mutation carriers: effect of mutation status on cancer incidence.

Annual MRI screening is recommended as an adjunct to mammography for BRCA1 and BRCA2 mutation carriers. Prophylactic oophorectomy has been shown to decrease breast cancer risk in BRCA1/2 mutation carriers. Here, we aimed to examine the combined effects of MRI and oophorectomy. For this purpose, 93 BRCA1/2 mutation carriers were screened with yearly mammograms and yearly MRI scans. Study endpoints were defined as date of breast cancer diagnosis, date of prophylactic mastectomy, or date of most recent contact. Of 93 women, with a median age of 47, 80 (86%) had prophylactic oophorectomy. Fifty-one women (55%) had BRCA1 mutations. A total of 283 MRI scans were performed. Eleven breast cancers (9 invasive, 2 ductal carcinoma in situ) were detected in 93 women (12%) with a median follow-up of 3.2 years (incidence 40 per 1,000 person-years). Six cancers were first detected on MRI, three were first detected by mammogram, and two were "interval cancers." All breast cancers occurred in BRCA1 mutation carriers (incidence 67 per 1,000 person-years). Apart from BRCA1 vs. BRCA2 mutation status, there were no other significant predictors of breast cancer incidence. Most invasive breast cancers were estrogen receptor negative (7 of 9) and lymph node negative (7 of 9). There have been no systemic recurrences with a median follow-up of 19 months after cancer diagnosis. Finally, it was concluded that all breast cancers occurred in BRCA1 mutation carriers, in most cases despite oophorectomy. These data suggest that surveillance and prevention strategies may have different outcomes in BRCA1 and BRCA2 mutation carriers.

Critical analysis of the ability of the endorectal coil magnetic resonance imaging scan to predict pathologic stage, margin status, and postoperative prostate-specific antigen failure in patients with clinically organ-confined prostate cancer.

PURPOSE: To determine whether there is a role for endorectal coil magnetic resonance imaging (erMRI) in the prediction of pathologic stage, margin status, and/or postoperative prostate-specific antigen (PSA) failure in patients with clinically organ-confined prostate cancer. PATIENTS AND METHODS: Using erMRI, the radiologic-pathologic correlation of extracapsular extension (ECE) and seminal vesicle invasion (SVI) was evaluated in 445 surgically managed patients. Logistic regression multivariable analysis was applied to the clinical stage, PSA, biopsy Gleason grade, and erMRI findings to assess the outcomes of ECE, SVI, positive surgical margins (PSM), and postoperative PSA failure. RESULTS: The accuracy of erMRI to predict for ECE and SVI numerically decreased with both increasing PSA and biopsy Gleason score because of the increasing false-negative scans in cases of microscopic transcapsular or seminal vesicle disease. Of patients who could not be categorized into low or high risk for postoperative PSA failure on the basis of clinical stage, preoperative PSA, and biopsy Gleason score, a negative or positive erMRI for ECE or SVI stratified these patients into groups with a 78% versus 21% (P < .0001) 3-year rate of actuarial freedom from PSA failure. In this subgroup, the overall accuracy of the erMRI was 70% +/- 6% and 94% +/- 2% for ECE and SVI, respectively. The most significant predictor on multivariable analysis of PSM was the erMRI finding of ECE (P = .0001). CONCLUSION: This initial report suggests that a preoperative erMRI can identify clinically organ-confined prostate cancer patients at high risk for having ECE, SVI, and PSM that otherwise would be missed on the basis of the clinical stage, preoperative PSA, and biopsy Gleason score. Confirmatory studies are needed.

Simultaneous 31P- and 1H-nuclear magnetic resonance studies of hypoxia and ischemia in the cat brain.

The objective of this study was to evaluate simultaneous 31P/1H nuclear magnetic resonance (NMR) spectroscopy as a technique for monitoring and correlating changes in brain energy metabolism during hypoxia and ischemia. Five cats were studied with a protocol that involved 20 min of hypoxia (PaO2 20 mm), 60 min of recovery, 10 min of hypoxia with relative ischemia (bilateral carotid occlusion, PaO2 20 mm), and 60 min of recovery. Bifrontal and biparietal electrocorticograms (ECoG) were monitored continuously during the entire protocol. The results demonstrate that the degree of metabolic response is different in individual cats, but a number of quantitative relationships between metabolic parameters are consistently observed for all cats. First, there is agreement between increases in lactate and changes in intracellular pH; the observed relationship corresponds to an in vivo cerebral buffer capacity of 29 mumol/g/pH unit. Second, the delayed recovery of PCr is due to the effect of metabolic acidosis on the creatine kinase equilibrium and not to a delayed recovery of the ATP/ADP ratio. Third, the observed rate of lactate clearance from the cell is zero-order (k = 0.36 mumol/g/min) for lactate levels greater than 5 microns/g and may be composed of both lactate efflux from the cell and lactate oxidation.

A multivariable analysis of clinical factors predicting for pathological features associated with local failure after radical prostatectomy for prostate cancer.

PURPOSE: A multivariate analysis is used to determine the predictive value of pretreatment clinical indicators on pathologic features associated with local failure after radical prostatectomy in patients with prostate cancer. METHODS AND MATERIALS: A retrospective review of the pathologic findings of 235 patients with adenocarcinoma of the prostate treated between 1990 and 1993 with a radical retropubic prostatectomy was performed. The preoperative clinical data including the serum prostate specific antigen, clinical stage, Gleason sum, and endorectal magnetic resonance scan findings are used to identify patients prior to definitive treatment who would be at high risk for having pathologic features associated with local failure at radical prostatectomy. Outcome prediction curves are constructed from a logistic regression multivariate analysis displaying the probability of pathologic involvement of the seminal vesicle, extracapsular disease, or positive surgical margins as a function of the preoperative prostate specific antigen and Gleason sum for the cases when the endorectal magnetic resonance scan is positive, negative, or not included in the multivariate analysis. RESULTS: Factors identified on multivariate analysis as significant predictors of seminal vesicle invasion include endorectal magnetic resonance scan findings (p < 0.0001), and preoperative prostate specific antigen (p = 0.017). Endorectal magnetic resonance scan findings (p = 0.0016), preoperative prostate specific antigen (p = 0.0002), and Gleason sum (p < 0.0001) were significant predictors of extracapsular extension and preoperative prostate specific antigen (p < 0.0001) and Gleason sum (p = 0.03) were significant predictors of disease extending to the margins of resection. Clinical stage was not a significant predictor (p > 0.05) of pathologic features associated with local failure on multivariate analysis. As a single modality, endorectal surface coil magnetic resonance imaging was accurate 93%, 69%, and 72% of the time for predicting seminal vesicle invasion, transcapsular disease, and final pathologic stage, respectively. Failure to recognize microscopic penetration of the capsule found at the time of pathologic evaluation in a prostate gland with a grossly intact capsule accounts for the majority (70%) of the staging inaccuracies. CONCLUSIONS: The use of the endorectal surface coil magnetic resonance scan findings in conjunction with both the serum prostate specific antigen and Gleason sum improves the clinical accuracy of predicting those patients at high risk for clinically unsuspected extraprostatic disease. In particular, for the subgroup of patients with moderately elevated prostate specific antigen (> 10-20 ng/mL) and intermediate grade clinically organ confined prostate cancer [Gleason sum: 5-7] where the specificity of these tests to predict for occult extraprostatic disease is suboptimal, the additional information obtained from the endorectal coil magnetic resonance scan allows the physician to definitively subgroup these patients into low and high risk for seminal vesicle invasion or transcapsular disease.

Endorectal coil magnetic resonance imaging identifies locally advanced prostate cancer in select patients with clinically localized disease.

OBJECTIVES: Endorectal coil magnetic resonance imaging (erMRI) has been reported to improve the prediction of pathologic Stage T3 disease in patients with clinical Stage T1,2 disease, prostate-specific antigen (PSA) of 10 to 20 ng/mL, biopsy Gleason score of 7 or less, and at least 50% of the biopsy specimens positive from a sextant sampling. This study examines the performance characteristics of the erMRI to predict established extracapsular extension (ECE), seminal vesicle invasion (SVI), and PSA failure-free survival (bNED) in this subgroup. METHODS: The sensitivity, specificity, positive and negative predictive value, and accuracy of the erMRI to predict established ECE and SVI were calculated in the proposed subgroup. PSA failure-free survival stratified by the erMRI-defined stage was estimated by using the method of Kaplan and Meier. RESULTS: The sensitivity, specificity, positive and negative predictive value, and accuracy to predict established ECE and SVI in clinical Stage T1,2 patients was 65%, 100%, 100%, 79%, and 84%, respectively. No patient would have been excluded from surgery on the basis of a false-positive study. Moreover, the percent of patients with pathologic organ-confined disease would have increased from 32% to 61%, and the 3-year bNED rate would have increased from 12% to 45% (P = 0.07) if only patients with erMRI Stage T2 disease were selected for surgery. CONCLUSIONS: The erMRI may significantly improve the identification of established ECE and SVI in select patients with prostate cancer preoperatively. Further study of the erMRI in these select patients is warranted and ongoing.

Combined modality staging of prostate carcinoma and its utility in predicting pathologic stage and postoperative prostate specific antigen failure.

OBJECTIVES: This study was performed to predict the factors that can optimize preoperative staging for clinically localized prostate cancer patients. METHODS: Logistic and Cox regression multivariable analyses were performed on 480 surgically-managed prostate cancer patients to evaluate the ability of clinical stage, prostate specific antigen (PSA), biopsy Gleason sum, percent positive biopsies, and endorectal coil magnetic resonance imaging (erMRI) results to predict for pathologic established extracapsular extension (ECE), seminal vesicle invasion (SVI), and time to postoperative PSA failure. RESULTS: The characteristics of clinically organ-confined prostate cancer patients at high risk (> 67%) for postoperative PSA failure within 3 years include: (A) PSA > 20 ng/mL; (B) Biopsy Gleason sum > or = 8; or (C) erMRI positive for extraprostatic disease and intermediate risk disease. For patients at intermediate risk (ie, either a PSA < 4 and biopsy Gleason sum of 7; PSA > 4 to 10 ng/mL and biopsy Gleason sum 5 to 7; or a PSA > 10 to 20 ng/mL and biopsy Gleason sum 2 to 7), despite 100% positive biopsies, 50% of patients had pathologic organ-confined disease. However, in the subset of intermediate-risk patients with a positive erMRI for either ECE or SVI and at least 50% positive biopsies, all had extraprostatic disease and failed biochemically by 47 months postoperatively. Intermediate-risk patients with < 50% positive biopsies had pathologic organ-confined disease in at least 77% of the cases. CONCLUSIONS: Combined modality staging using the PSA, biopsy Gleason sum, percent positive biopsies, and endorectal coil MRI findings in select patients can predict pathologic stage and postoperative PSA failure. Therefore, this combined modality staging may optimize patient selection for phase 3 trials examining the role of neoadjuvant androgen ablative therapy for patients with clinically localized disease.

An analysis of the time course of postoperative prostate-specific antigen failure in patients with positive surgical margins: implications on the use of adjuvant therapy.

OBJECTIVES: The role of adjuvant therapy in the postprostatectomy setting for positive margin patients is an unresolved issue. The purpose of this study is to provide the rationale for patient selection in Phase III trials that test the impact of adjuvant therapy on survival in positive margin prostate cancer patients. METHODS: Early (12 months or less) and delayed (more than 12 months) postoperative prostate-specific antigen (PSA) failure have been correlated with distant and local failure, respectively, as the site of first failure. In this study, a Cox regression multivariate analysis was used to determine the significant independent clinical and pathologic predictors of early and delayed postoperative PSA failure in 143 margin-positive prostate cancer patients. RESULTS: Margin-positive patients with positive pelvic lymph nodes, seminal vesicle invasion, or prostatectomy Gleason sum 8 or higher were excluded. For the remaining patients, a prostatectomy Gleason sum of 7, preoperative PSA more than 20 ng/mL, and an endorectal coil magnetic resonance imaging (erMRI) scan showing extensive disease were significant independent predictors of early postoperative PSA failure. Conversely, a prostatectomy Gleason sum of 6 or less, preoperative PSA 20 ng/mL or less, and an erMRI showing limited disease predicted delayed PSA failure. CONCLUSIONS: Preliminary data suggest that the pattern of first failure can be predicted by the time course of rise in the postoperative PSA. The preliminary results of this study suggest that patient selection for clinical trials examining the efficacy of postoperative adjuvant therapy in the positive margin patient may be determined on the basis of the clinical and pathologic characteristics that predict early versus delayed postoperative PSA failure.

Electrical stimulation of human muscle studied using 31P-nuclear magnetic resonance spectroscopy.

This study used phosphorous nuclear magnetic resonance (31P-NMR) spectroscopy to examine the metabolic demand resulting from electrical muscle stimulation (EMS) applied to human skeletal muscle. For each of six subjects, the forearm flexor muscle group was monitored with 31P-NMR during both maximum voluntary and 6-s EMS-induced contractions. A simple protocol using a tourniquet was added in one subject to assess the role of blood flow in this model. Eight hertz (nontetanic) EMS showed less (p less than 0.025) depletion of phosphocreatine (36%) than did tetanic 70-Hz EMS (60%), voluntary isometric (66%), and voluntary isokinetic (68%). The results of the tourniquet studies suggested that the nontetanic EMS allowed relatively increased muscle blood flow and oxygen supply during contraction. Tetanic EMS provided a similar metabolic demand to that of conventional resistive exercise, as measured by 31P-NMR spectroscopy.

Magnetization transfer imaging of the head and neck: normative data.

PURPOSE: To determine magnetization transfer ratios for normal head and neck structures so that evaluation of disease will be possible. METHODS: Two-dimensional magnetization transfer imaging was performed in 12 healthy volunteers and 20 patients. We used a repetition time of 500, echo time of 12, 20 degrees flip angle, and a magnetization transfer pulse offset from the resonance frequency of water by 2000 Hz (pulse duration 19 milliseconds, waveform area approximately 10 times greater than that of a 90 degree pulse). Magnetization transfer ratios (1 - [intensity after suppression/intensity before suppression]) were calculated for normal structures. RESULTS: The magnetization transfer ratio of facial muscles (0.54) was equivalent to that of tongue muscles (0.54). These values exceeded those of parotid (0.39) and submandibular glands (0.41). Fat (0.07) and cerebrospinal fluid (0.05) had negligible transfer. CONCLUSION: Magnetization transfer imaging is a simple and effective means of studying the contribution of macromolecular protons to the MR image. Normal neck structures show a wide range of magnetization transfer rates, maximal for muscle and minimal for cerebrospinal fluid and fat.

The low sensitivity of fluid-attenuated inversion-recovery MR in the detection of multiple sclerosis of the spinal cord.

PURPOSE: To confirm the expected superiority of fluid-attenuated inversion-recovery (FLAIR) over conventional fast spin-echo MR imaging in the detection of multiple sclerosis (MS) of the spinal cord. METHODS: Fifteen subjects with known MS involving the spinal cord and brain were studied prospectively. The entire cord was imaged with a phased-array coil on a 1.5-T MR system. Sagittal T1-weighted and fast spin-echo proton density- and T2-weighted images were followed by fast FLAIR images. FLAIR parameters were varied to optimize lesion conspicuity with optimal inversion times (TIs) ranging from 2400 to 2600. Lesion conspicuity and detection were compared between the fast spin-echo and FLAIR images by three radiologists who reached agreement by consensus. RESULTS: The FLAIR technique effectively suppressed cerebrospinal fluid (CSF) signal and reduced CSF pulsation and truncation artifacts in all cases. Shorter imaging parameters (repetition time of 4000 to 6000, TI of 1500 to 2000) uniformly decreased lesion conspicuity in all subjects. Of 11 cord lesions in five subjects imaged with the longer parameters (repetition time of 8000 to 11,000, TI of 2400 to 2600), three were not seen on FLAIR images, four were less conspicuous on FLAIR images, and four were seen equally or better on FLAIR images. CONCLUSION: Although successful in suppressing CSF signal and reducing imaging artifacts, fast FLAIR imaging appears unreliable in the detection of MS lesions in the spinal cord.

An in vitro study of magnetization transfer and relaxation rates of hematoma.

PURPOSE: To assess, in an in vitro model of acute hematoma, whether hemoglobin immobilization by clot and red cell membrane aging can account for the T2 shortening usually attributed to deoxyhemoglobin. METHODS: Clotted and heparinized blood samples were packed (100% hematocrit). The apparent magnetization transfer rate (AMTR), T1 and T2 relaxation rates of the samples, and images with a volunteer's head were obtained at 1.5 T. RESULTS: The AMTR and T1 and T2 relaxation rates were unaffected by the presence of clot. The AMTR was unaffected by red cell aging. The diamagnetic packed blood samples, which are much denser than brain, were isointense to gray matter on T2-weighted images and had about one-fifth the AMTR of white matter. CONCLUSIONS: Hemoglobin immobilization by clot structure or red cell contraction with aging is insignificant and does not contribute to the T2 shortening of acute hematoma. The low AMTR and T2 relaxation rates of diamagnetic blood appear to be caused by the mobility of hemoglobin and by the red cell's lack of immobile macromolecular structures such as those associated with nucleated brain cells.

Magnetization transfer effects in MR imaging of in vivo intracranial hemorrhage.

PURPOSE: Recent papers have hypothesized that diamagnetic effects of clotting and conformational changes in aging red blood cells immobilize the hemoglobin protein and thus are responsible for the marked hypointensity of acute hematomas on T2-weighted spin-echo MR images. To test that hypothesis, the authors evaluated 24 hemorrhagic components of intracranial hemorrhagic lesions using accepted criteria based on spin-echo images as the definitions of the stage of the hemorrhage. METHODS: As a measure of the effects of macromolecular (hemoglobin protein) immobility, magnetization transfer contrast was elicited using a pulsed saturation magnetization transfer experiment. The apparent magnetization transfer contrast (AMTC) was determined by comparing the signal intensities of saturated with unsaturated images and quantified for acute isolated hemorrhages, acute nonisolated hemorrhagic lesions, and subacute-to-chronic hemorrhages. RESULTS: The AMTC of isolated acute hemorrhage was significantly less than that of normal, white matter and gray matter, indicating the lack of significant magnetization transfer and therefore the lack of effects of restriction of hemoglobin mobility on the signal intensity of acute hemorrhage. Acutely hemorrhagic tissue (nonisolated acute hemorrhage) has significantly more AMTC than isolated acute hemorrhage, but still not exceeding that of brain parenchyma. CONCLUSION: This in vivo data concurs with in vitro data and reinforces the concept that the marked hypointensity of acute hematomas is mainly a magnetic susceptibility effect.

Effects of increased ICP on brain phosphocreatine and lactate determined by simultaneous 1H and 31P NMR spectroscopy.

In order to study the metabolic events surrounding ischemia induced by the graded increase of cerebrospinal fluid (CSF) pressure, the technique of simultaneous phosphorus-31- and hydrogen-1-enhanced nuclear magnetic resonance spectroscopy was applied to five cats as intracranial pressure (ICP) was gradually raised by the instillation of mock CSF. Threshold lactate rose at an average cerebral perfusion pressure (CPP) of 49 torr, and, in general, preceded a threshold decrease in phosphocreatine, which was observed at an average CPP of 29 torr. There was considerable variation among cats in the CPP at which failure of brain energy metabolism occurred, however, suggesting differences in the autoregulatory curves. It is concluded that, with elevated ICP, there is no universally "safe" CPP at which brain energy metabolism may be assumed to be uncompromised.

Role of magnetic resonance imaging and magnetic resonance imaging--guided surgery in the evaluation of patients with early-stage breast cancer for breast conservation treatment.

Magnetic resonance imaging (MRI) may be more sensitive than mammography for detecting breast cancer and may have an adjunctive role in assessing patients with early-stage disease for breast conservation treatment. This study was performed to analyze the impact of breast MRI on the clinical management of 83 patients being considered for breast conservation treatment. Eighty-three consecutive cases of patients undergoing breast MRI during standard workup and evaluation for breast conservation treatment from 1993 to 1996 were retrospectively reviewed. Records were reviewed for patient and tumor characteristics, mammographic findings, MRI findings, timing of MRI study, findings from MRI-guided surgery (when done), and whether the patient underwent breast conservation treatment. MRI definitely altered management in 15 patients (18%), may have affected management in 4 patients (5%), and did not change management in 64 patients (77%). Thirteen patients underwent additional surgery because of MRI findings; the positive predictive value for MRI-guided surgery was 38% (5 of 13). Ultimately, 82% of the patients received breast conservation treatment. No predictive factor was identified to characterize the patients most likely to have management affected by MRI findings. These findings suggest that breast MRI may be useful in the evaluation of patients with early-stage breast cancer for breast conservation treatment. A larger study population and outcome data will be required to confirm these findings and to define those patients most likely to benefit from breast MRI.

A deformable finite element model of the breast for predicting mechanical deformations under external perturbations.

RATIONALE AND OBJECTIVES: Live guidance during needle breast procedures is not currently possible with high-field-strength (1.5-T), superconducting magnetic resonance (MR) imaging. The physician can calculate only the approximate location and extent of a tumor in the compressed patient breast before inserting the needle, and the tissue specimen removed at biopsy may not actually belong to the lesion of interest. The authors developed a virtual reality system for guiding breast biopsy with MR imaging, which uses a deformable finite element model of the breast. MATERIALS AND METHODS: The geometry of the model is constructed from MR data, and its mechanical properties are modeled by using a nonlinear material model. This method allows the breast to be imaged with or without mild compression before the procedure. The breast is then compressed, and the finite element model is used to predict the position of the tumor during the procedure. Three breasts of patients with cancer were imaged with and without compression. Deformable models of these breasts were built, virtually compressed, and used to predict tumor positions in the real compressed breasts. The models were also used to register MR data sets of the same patient breast imaged with different amounts of compression. RESULTS: The model is shown to predict reasonably well the displacement by plate compression of breast lesions 5 mm or larger. CONCLUSION: A deformable model of the breast based on finite elements with nonlinear material properties can help in modeling and predicting breast deformation. The entire procedure lasts less than half an hour, making it clinically practical.

Discrimination of MR images of breast masses with fractal-interpolation function models.

RATIONALE AND OBJECTIVES: The authors evaluated the feasibility of using statistical fractal-dimension features to improve discrimination between benign and malignant breast masses at magnetic resonance (MR) imaging. MATERIALS AND METHODS: The study evaluated MR images of 32 malignant and 20 benign breast masses from archived data at the University of Pennsylvania Medical Center. The test set included four cases that were difficult to evaluate on the basis of border characteristics. All diagnoses had been confirmed at excisional biopsy. The fractal-dimension feature was computed as the mean of a sample space of fractal-dimension estimates derived from fractal interpolation function models. To evaluate the performance of the fractal-dimension feature, the classification effectiveness of five expert-observer architectural features was compared with that of the fractal dimension combined with four expert-observer features. Feature sets were evaluated with receiver operating characteristic analysis. Discrimination analysis used artificial neural networks and logistic regression. Robustness of the fractal-dimension feature was evaluated by determining changes in discrimination when the algorithm parameters were perturbed. RESULTS: The combination of fractal-dimension and expert-observer features provided a statistically significant improvement in discrimination over that achieved with expert-observer features alone. Perturbing selected parameters in the fractal-dimension algorithm had little effect on discrimination. CONCLUSION: A statistical fractal-dimension feature appears to be useful in distinguishing MR images of benign and malignant breast masses in cases where expert radiologists may have difficulty. The statistical approach to estimating the fractal dimension appears to be more robust than other fractal measurements on data-limited medical images.

A combined architectural and kinetic interpretation model for breast MR images.

RATIONALE AND OBJECTIVES: The purpose of this study was to integrate contrast material kinetic and architectural data from magnetic resonance (MR) images and to assess the improvement in diagnostic accuracy. MATERIALS AND METHODS: MR imaging data from a diagnostic cohort of 100 patients (50 malignant and 50 benign cases) were analyzed. RESULTS: Qualitative classification of the enhancement curve was the most predictive kinetic feature. Receiver operating characteristic (ROC) curves were calculated for the architectural model alone and for the architectural model combined with the qualitative kinetic classification. The results demonstrated a statistically significant increase in ROC area (P = .03) of the combined model compared with that of the architectural model alone. CONCLUSION: The addition of qualitative classification of the time-signal intensity curve to an architectural interpretation model results in significant improvement in model performance as measured by the area under the ROC curve.

An overview of interpretation strategies for breast MR imaging.

This article provides an overview of the different approaches to the interpretation of breast MR imaging. It provides an overview of the use of architectural features for breast MR imaging interpretation. It also includes a discussion of the various types of contrast kinetic data that are used for breast MR imaging interpretation. Approaches to combine architectural and kinetic features are also discussed. This article serves as an introduction to the other articles in this issue that discuss specific interpretation and strategies.

MR imaging: its current and potential utility in the diagnosis and management of breast cancer.

The rapid evolution of the treatment of breast cancer has been paralleled by a similar rapid improvement in the imaging of breast cancer. High-resolution contrast-enhanced MR imaging of the breast has recently emerged as a sensitive instrument for the detection of breast cancer. The sensitivity of MR imaging makes it an excellent tool in specific clinical situations, such as the detection of local recurrence in patients who have received breast-conservation therapy. Furthermore, MR imaging of the breast has the potential to be a powerful aid in presurgical planning and to be a useful adjunct to mammography in selected patients. MR imaging, however, has a significant false-positive rate, is not readily available in all areas, and is more expensive than mammography and sonography. It also remains unclear if alterations of management plans based on MR imaging findings actually benefit affected patients. Therefore rigorous clinical trials are needed to define precisely the exact role that MR imaging should play in the diagnosis and management of breast cancer patients.

Contrast-enhanced MR imaging of the bladder and prostate.

The staging of both bladder and prostate carcinoma is important to determine appropriate therapy. Routine clinical staging of these tumors, however, has only limited accuracy. This article reviews the literature on contrast-enhanced MR of both bladder and prostate cancer, including technique optimization and potential benefits of contrast-enhanced studies.