Nuclear magnetic resonance in the diagnosis of breast cancer
Department of Diagnostic Radiology and Nuclear Medicine, Rush Medical College, Chicago, Illinois.Radiologic Clinics of North America (Impact Factor: 1.98). 06/1988; 26(3):673-87.
We believe that the preponderance of evidence suggests that MRI is less accurate than conventional mammography in the diagnosis of primary cancer of the breast. Thus, it currently has no established place in algorithms for the evaluation of patients suspected of having breast cancer. MRI could be used to evaluate masses with mammographically smooth, well-defined margins, since high signal intensity (greater than fat) in a T2-weighted image is a highly specific indicator of benignancy in such lesions. However, most of these masses are cysts and can be reliably and less expensively identified as such by sonography. Nonetheless, MRI might be used to re-evaluate a smooth, well-defined mass if sonography has failed to identify the lesion as a cyst. MRI might be particularly useful in this regard if a lesion is difficult to evaluate by other modalities because it is located adjacent to the chest wall, is deep within a very large breast, or is obscured by a breast prosthesis. MRI with Gd-DTPA may be useful in evaluating radiographically dense breasts or in differentiating breast malignancies from irregular dysplastic or scar tissue. However, further investigation of this technique is needed. It has been hoped that in vivo measurement of T1 and T2 or in vivo NMR spectroscopy might improve the accuracy of noninvasive diagnosis of cancer of the breast. However, there is currently no credible evidence that in vivo measurements of relaxation times provide useful indexes for the diagnosis of breast cancer. In vivo NMR spectroscopy of nuclei other than P may ultimately provide reliable criteria for noninvasive diagnosis of breast cancer in humans, but the technique is currently in its infancy.
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ABSTRACT: Gd-DOTA contrast enhancement of MR images was evaluated on induced mammary tumors in female rats. A single intravenous injection of the carcinogenic N-nitrosourea ENU was administered to Wistar rats; this simple treatment led to a high percentage of mammary tumors without causing death. All the induced tumors were adenocarcinoma and their heterogeneousness depended on their size. The induced tumors did not have intra- or extravascular inflammatory spaces caused by heterotopic lesions, as is the case with implanted tumors. Before injection of Gd-DOTA, appearance of the patchy internal structure was clearly demonstrated on spin-echo images performed with long repetition times. Three doses of the paramagnetic contrast agent (0.1, 0.2, and 0.5 mmol/kg) were evaluated on two different T1-weighted MR sequences. Images were recorded before and repeatedly after intravenous injection of Gd-DOTA, and signal intensities and relaxation times were measured. On images acquired with the spin-echo 500/28 as well as the inversion-recovery 928/26/300 sequences, the results showed that 0.2 mmol/kg Gd-DOTA was the optimal dose for contrast enhancement and for clear visualization of the heterogeneousness of the mammary tumor.Magnetic Resonance Imaging 02/1990; 8(1):71-7. DOI:10.1016/0730-725X(90)90215-N · 2.09 Impact Factor
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ABSTRACT: Single slice MR images were obtained from 9 normal breasts, 17 breasts with benign tumors, and 11 breasts with malignant tumors using an interleaved (mixed) spin echo (SE) inversion-recovery (IR) imaging sequence. SE and IR MR images were synthesized with variable repetition, echo and inversion times from the mixed sequence data. These images were used to qualitatively evaluate the contrast possibilities available when imaging the breast with MR imaging. Proton T1 and T2 relaxation times were determined for normal breast tissues and malignant and benign breast tumors from pure T1 and T2 images calculated using the mixed sequence data. The mean T1 value in benign tumors of 1,049.02 +/- 40.31 was found to be significantly longer (p < 0.0001) than the mean value of malignant tumors (876.09 +/- 27.83) and normal tissues (795.64 +/- 21.12). The value of T2 in benign tumors (89.15 +/- 8.33) was significantly longer (p < 0.01) than the value of T2 in normal tissues (62.82 +/- 4.06). The mixed sequence can be applied to improve image contrast between malignant tumors, benign tumors, and normal tissues of the breast and can potentially differentiate between these tissues in vivo.Acta Radiologica 07/1993; 34(4):356-61. DOI:10.1080/02841859309173257 · 1.60 Impact Factor
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ABSTRACT: A dynamic contrast-enhanced MRI technique for whole breast examinations is presented. The fast kinetics of tissue response during and after constant-rate intravenous infusion of gadolinium diethylenetriaminopentaacetic acid was resolved using a strongly T1-weighted saturation recovery TurboFLASH sequence that makes it possible to acquire signal-time courses sequentially from 15 adjacent slices with a temporal sampling rate of 21 s. On the basis of the mathematically established and experimentally verified linear relationship between the measured saturation recovery TurboFLASH signal variation and the gadolinium diethylenetriaminopentaacetic acid concentration in the tissue, the signal-time courses were analyzed within the framework of pharmacokinetic modeling. In our study, the tissue response was parameterized adequately using an open linear two-compartment model. With this approach, the tissue specific information contained in the signal-time course can be described using only two parameters: an amplitude A, reflecting the degree of MR signal enhancement, and an exchange parameter k21, characterizing vascular permeability and perfusion of the tissue. A clearly arranged representation of the large amount of data (480 saturation recovery TurboFLASH breast images/examination) was accomplished by means of color coding of the computed parameters, resulting in one color-coded pharmacokinetic parameter map/cross-section.Magnetic Resonance in Medicine 04/1995; 33(4):506-14. DOI:10.1002/mrm.1910330408 · 3.57 Impact Factor
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