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Christiane K Kuhl

Publications and source records attributed to Christiane K Kuhl.

17 recordsLinked to original sources
PubMed2006

Contrast-enhanced MR imaging of the breast at 3.0 and 1.5 T in the same patients: initial experience.

PURPOSE: To establish a pulse sequence for dynamic contrast material-enhanced magnetic resonance (MR) imaging of the breast at 3.0 T and to prospectively compare MR imaging at 3.0 T with MR imaging at 1.5 T in the same patients. MATERIALS AND METHODS: A prospective intraindividual internal review board-approved study was performed in 37 women with 53 lesions (25 breast cancers, 28 benign focal lesions) who underwent contrast-enhanced dynamic bilateral subtraction MR imaging twice, once at 1.5 T with a standard technique (voxel size, 1.44 mm3) and once at 3.0 T (voxel size, 0.45-0.72 mm3) with variable repetition time and flip angle settings. Written informed consent was obtained. Sagittal single breast high-spatial-resolution MR imaging was performed with active fat suppression. Image quality, number and features of enhancing lesions, and Breast Imaging Reporting and Data System categories were compared by using the Wilcoxon matched-pairs signed rank test and Student t test for matched pairs. Diagnostic confidence was compared by using a receiver operating characteristic (ROC) analysis. RESULTS: With repetition time prolonged to account for longer T1 relaxation times at 3.0 T and a flip angle of 60 degrees, enhancement rates at 3.0 T were substantially below those at 1.5 T. In two patients with benign lesions, enhancement was rated as insufficient to establish diagnosis. When parameter settings were kept equivalent, equivalent enhancement rates were observed with both systems. With these settings, 3.0-T MR imaging yielded homogeneous signal intensity over the entire field of view. No dielectric resonance effects were observed. Overall image quality scores for the dynamic series were slightly higher at 3.0 T (P<.01). A total of 49 lesions were prospectively identified with both systems. Owing to substantial patient motion at 1.5 T, two malignant lesions in one patient were visualized at 3.0 T only. At 3.0 T, differential diagnosis of enhancing lesions was possible with higher diagnostic confidence, as reflected by a larger area under the ROC curve (P<.05). CONCLUSION: Initial experiences indicate that contrast-enhanced MR imaging at 3.0 T is nearing readiness for clinical use.

Adult↗
PubMed2006

Diagnostic architectural and dynamic features at breast MR imaging: multicenter study.

PURPOSE: To prospectively determine the prevalence and predictive value of three-dimensional (3D) and dynamic breast magnetic resonance (MR) imaging and contrast material kinetic features alone and as part of predictive diagnostic models. MATERIALS AND METHODS: The study protocol was approved by the institutional review board or ethics committees of all participating institutions, and informed consent was obtained from all participants. Although study data collection was performed before HIPAA went into effect, standards that would be compliant with HIPAA were adhered to. Data from the International Breast MR Consortium trial 6883 were used in the analysis. Women underwent 3D (minimum spatial resolution, 0.7 x 1.4 x 3 mm; minimal temporal resolution, 4 minutes) and dynamic two-dimensional (temporal resolution, 15 seconds) MR imaging examinations. Readers rated enhancement shape, enhancement distribution, border architecture, enhancement intensity, presence of rim enhancement or internal septations, and the shape of the contrast material kinetic curve. Regression was performed for each feature individually and after adjustment for associated mammographic findings. Multivariate models were also constructed from multiple architectural and dynamic features. Areas under the receiver operating characteristic curve (Az values) were estimated for all models. RESULTS: There were 995 lesions in 854 women (mean age, 53 years +/- 12 [standard deviation]; range, 18-80 years) for whom pathology data were available. The absence of enhancement was associated with an 88% negative predictive value for cancer. Qualitative characterization of the dynamic enhancement pattern was associated with an Az value of 0.66 across all lesion architectures. Focal mass margins (Az = 0.76) and signal intensity (Az = 0.70) were highly predictive imaging features. Multivariate models were constructed with an Az value of 0.880. CONCLUSION: Architectural and dynamic features are important in breast MR imaging interpretation. Multivariate models involving feature assessment have a diagnostic accuracy superior to that of qualitative characterization of the dynamic enhancement pattern.

Adolescent↗
PubMed2005

Dynamic contrast-enhanced breast MR imaging in men: preliminary results.

PURPOSE: To prospectively evaluate whether the descriptors of lesion features and the diagnostic criteria that have been established for breast magnetic resonance (MR) imaging in female patients may be used for differential diagnosis with breast MR imaging in male patients as well. MATERIALS AND METHODS: The study design was approved by the institutional review board; all patients gave informed consent. The Institutional Review Board and informed consent information applied to the prospective and any retrospective component of the study. Seventeen consecutive male patients (mean age, 53 years +/- 14) were referred for imaging of a palpable breast mass. In addition to mammography and high-frequency breast ultrasonography, patients underwent dynamic breast MR imaging in a prone position with a dedicated double-breast surface coil. The standardized protocol consisted of a T2-weighted turbo spin-echo sequence followed by a dynamic series. Findings were recorded by using the terminology and descriptors and by evaluating the diagnostic criteria (related to morphology and enhancement kinetics) that have been developed for breast MR imaging in female patients. Validation was achieved at biopsy (nine patients) or follow-up with clinical examination and conventional imaging (eight patients). Because of the small size of the patient cohort, statistical significance was not tested. RESULTS: A total of 24 breast abnormalities were diagnosed. Three patients had invasive breast cancer (five tumors), 11 had gynecomastia (six unilateral, five bilateral), two had pseudogynecomastia, and one had a benign solid tumor (angiolipoma). All malignant tumors appeared as irregular masses with heterogeneous internal architecture or rim enhancement and showed rapid initial enhancement (mean value, 137% +/- 23) followed by a washout time course (Breast Imaging Reporting and Data System [BI-RADS] category 5). Diffuse and nodular gynecomastia showed slow initial and persistent enhancement with normal-appearing parenchymal architecture (BI-RADS category 2; 15 of 16 breasts in 10 of 11 patients). In one patient with biopsy-proved bilateral gynecomastia, an area with segmental enhancement was classified as suspicious for ductal carcinoma in situ. Pseudogynecomastia did not enhance at all. The angiolipoma showed benign morphologic features and slow initial and persistent enhancement (BI-RADS category 2). CONCLUSION: In the small study cohort, the MR imaging features of benign breast diseases and breast cancers in male patients seemed to be comparable to those seen in female patients.

Adult↗
PubMed2005

Mammography, breast ultrasound, and magnetic resonance imaging for surveillance of women at high familial risk for breast cancer.

PURPOSE: To compare the effectiveness of mammography, breast ultrasound, and magnetic resonance imaging (MRI) for surveillance of women at increased familial risk for breast cancer (lifetime risk of 20% or more). PATIENTS AND METHODS: We conducted a surveillance cohort study of 529 asymptomatic women who, based on their family history and/or mutational analysis, were suspected or proven to carry a breast cancer susceptibility gene (BRCA). A total of 1,542 annual surveillance rounds were completed with a mean follow-up of 5.3 years. Diagnostic accuracies of the three imaging modalities used alone or in different combinations were compared. RESULTS: Forty-three breast cancers were identified in the total cohort (34 invasive, nine ductal carcinoma-in-situ). Overall sensitivity of diagnostic imaging was 93% (40 of 43 breast cancers); overall node-positive rate was 16%, and one interval cancer occurred (one of 43 cancers, or 2%). In the analysis by modality, sensitivity was low for mammography (33%) and ultrasound (40%) or the combination of both (49%). MRI offered a significantly higher sensitivity (91%). The sensitivity of mammography in the higher risk groups was 25%, compared with 100% for MRI. Specificity of MRI (97.2%) was equivalent to that of mammography (96.8%). CONCLUSION: Mammography alone, and also mammography combined with breast ultrasound, seems insufficient for early diagnosis of breast cancer in women who are at increased familial risk with or without documented BRCA mutation. If MRI is used for surveillance, diagnosis of intraductal and invasive familial or hereditary cancer is achieved with a significantly higher sensitivity and at a more favorable stage.

Adult↗
PubMed2005

Brain tumors: full- and half-dose contrast-enhanced MR imaging at 3.0 T compared with 1.5 T--Initial Experience.

PURPOSE: To prospectively and intraindividually compare the effect of magnetic resonance (MR) imaging at a higher magnetic field strength (3.0 T) on contrast-to-noise ratio (CNR) at different doses of a T1-shortening contrast agent in patients with contrast-enhancing brain lesions, with 1.5-T MR imaging as a reference standard. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained for all patient and volunteer studies. Twelve patients (six women, six men; mean age, 58 years; range, 29-76 years) with 12 enhancing brain lesions (11 patients with primary brain tumors and one with a solitary cerebral metastasis) underwent contrast material-enhanced MR imaging three times, on three separate days: once at 1.5 T with a full dose of 0.10 mmol/kg gadopentetate dimeglumine, once at 3.0 T with a full dose, and once at 3.0 T with half that dose, 0.05 mmol/kg. The same contrast-enhanced T1-weighted spin-echo images (repetition time msec/echo time msec, 500/12; section thickness, 5 mm; matrix, 256 x 205) were obtained at both 3.0 T and 1.5 T after prior optimization of parameters at 3.0 T. The number and conspicuity of enhancing brain lesions were assessed with blinded clinical image reading. Signal-to-noise ratio and CNR were determined with region of interest analysis of enhancing lesions and normal contralateral white matter. For 3.0 T with half the standard dose and with the full dose, CNR of lesions was intraindividually compared with CNR at 1.5 T with the full dose by using the Wilcoxon matched-pairs signed rank test. RESULTS: At 3.0 T and full dose, CNR was 2.8-fold higher than that at 1.5 T and full dose (P < .001). At the same time, higher lesion conspicuity at clinical image reading was observed. With only half the standard dose, MR imaging at 3.0 T still yielded higher CNR (1.3-fold higher) than that with full dose at 1.5 T (P < .01). CONCLUSION: With the same amount of contrast agent, MR imaging at 3.0 T offered a significantly higher CNR of enhancing cerebral lesions, compared with that at 1.5 T; even with the dose reduced by half, CNR was still higher at 3.0 T.

Adult↗
PubMed2005

MRI detection of distinct incidental cancer in women with primary breast cancer studied in IBMC 6883.

BACKGROUND: Prior single institution studies suggest MRI may improve the assessment of the extent of cancer within the breast, and thus reduce the risk of leaving macroscopic disease in the breast following breast conservation therapy. We report on the rate of MRI and mammography detection of foci of distinct incidental cancer in a prospective, multi center trial involving 426 women with confirmed breast cancer at 15 institutions in the US, Canada, and Germany. METHODS: Women underwent mammography and MRI prior to biopsy of the suspicious index lesion. Additional incidental lesions (IL) greater than 2 cm from the index lesion that were detected by mammography and MRI were noted and characterized. Biopsy recommendations were associated with ILs given an assessment of suspicious or highly suspicous (BiRads 4 and 5). These assessments were considered a positive test. RESULTS: MRI had a significantly higher yield of confirmed cancer ILs than mammography (0.18 (95%CI: 0.142-0.214) for MRI versus 0.072 (95%CI: 0.050-0.100) for mammography). The cancer ILs detected by MRI alone appeared to be similar to those detected by mammography with respect to size and histology. The percentage of biopsies of ILs that resulted in a cancer diagnosis was similar between the modalities (MRI 0.72(95%CI: 0.6-0.81); Mammography 0.85 (95%CI: 0.62-0.96)). CONCLUSIONS: These results suggest that consideration needs to be given regarding the integration of breast MRI into the pretreatment evaluation of women seeking breast conservation therapy.

Biopsy↗
PubMed2005

Three-dimensional dynamic susceptibility-weighted perfusion MR imaging at 3.0 T: feasibility and contrast agent dose.

PURPOSE: To prospectively investigate if T2*-weighted dynamic susceptibility-weighted first-pass perfusion magnetic resonance (MR) imaging is feasible at 3.0 T and which dose of contrast agent is suitable for high-field-strength imaging. MATERIALS AND METHODS: Informed consent was obtained from all participants; study protocol was approved by the institutional review board. Study included three volunteers (two men, one woman aged 35, 39, and 52 years) and 26 patients (mean age, 49 years +/- 12.8 [standard deviation]; range, 19-76 years). Volunteers underwent 3.0-T perfusion MR imaging with 0.20, 0.10, and 0.05 mmol per kilogram body weight of gadopentetate dimeglumine; patients underwent imaging with 0.10- and 0.05-mmol doses. Perfusion MR imaging was performed with three-dimensional echo-shifted echo-planar imaging (repetition time msec/echo time msec, 14/21; isotropic 4 mm3 voxels; 50 dynamic volumes with 30 sections each, covering entire brain at temporal resolution of 1.5 seconds per MR image). Quality of source echo-planar images and perfusion maps was assessed; perfusion maps obtained at studies with different contrast media doses were compared. Quantitative perfusion values and diagnostic sensitivity of perfusion studies with 0.10-mmol dose were compared with results with 0.05-mmol dose. Image quality scores were compared with marginal homogeneity test for multinomial variables (Mantel-Haenszel statistics for ordered categorized values). Signal-to-noise ratio and baseline signal intensity in perfusion studies were tested (Student t test for paired samples). Mean transit time (MTT), negative integral (NI), and maximum T2* effect from region-of-interest analysis were compared (one-tailed Student t test for paired samples). Quantitative data on number of gamma-fitted pixels were compared (t test for paired samples). Difference with P=.05 (t test for paired samples) was considered significant. RESULTS: Perfusion image quality was satisfactory even in areas close to skull base (47 of 52 images, minor distortions; remaining images, marked distortions). Perfusion imaging with 0.20-mmol dose caused almost complete signal cancellation during first pass, particularly in cortical gray matter, since mean maximum T2* effect of 98%, 99%, and 98% for gray matter was reached such that the accurate calculation of perfusion maps was impossible. With 0.10-mmol dose, the NI and maximum T2* effect were comparable to published data for 1.5-T perfusion imaging with 0.20- and 0.05-mmol doses; perfusion maps of sufficient diagnostic quality were obtained. For gray matter, mean maximum T2* effect was 25.4% +/- 9.8 with 0.10-mmol dose and 17.5% +/- 9.0 with 0.05-mmol dose. For white matter, mean maximum T2* effect was 15.2% +/- 4.5 with 0.10-mmol dose and 7.7% +/- 2.9 with 0.05-mmol dose. Difference in maximum signal intensity decrease was significant (P <.01). For NI, the difference between 0.10- and 0.05-mmol doses was significant: For gray matter, mean NI was 3.1 +/- 1.60 for 0.10-mmol dose and 1.56 +/- 1.16 for 0.05-mmol dose. For white matter, mean NI was 1.35 +/- 0.59 with 0.1-mmol dose and 0.59 +/- 0.30 with 0.05-mmol dose. CONCLUSION: With echo-shifted multishot echo-planar imaging, dynamic susceptibility-weighted perfusion MR imaging at high field strength is feasible without relevant image distortions. Compared with contrast agent dose for 1.5 T imaging, the dose for 3.0 T can be reduced to 0.10 mmol.

Adult↗
PubMed2005

Functional 3.0-T MR assessment of higher cognitive function: are there advantages over 1.5-T imaging?

PURPOSE: To compare cortical activation patterns associated with manual motor decision tasks at 1.5- and 3.0-T functional magnetic resonance (MR) imaging. MATERIALS AND METHODS: The local ethics committee approved this study, and informed written consent was obtained. Ten right-handed healthy volunteers (eight men and two women; mean age, 35 years +/- 7 [standard deviation]) underwent functional MR imaging twice, once at 1.5 T and once at 3.0 T, while performing cognitive tasks that demanded manual motor decisions (letter-finger matching and lexical and semantic decisions). While stimulus presentation was blocked, an event-related model was employed to analyze subjects' individual responses. A group analysis of functional data was performed with a t test of 1.5- and 3.0-T results in the 10 subjects. RESULTS: Manual motor decisions activated a widespread network of motor- (primary motor, posterior parietal) and decision-related areas (superior frontal cortex or anterior cingulate) at both field strengths (P <.05, corrected). Moreover, additional functional activation was detected in medial (supplementary motor area) and dorsal premotor regions (P <.05, corrected) at 3.0-T functional MR imaging, which was not detectable with corresponding 1.5-T imaging. The mean t value for peak voxels in activated areas detectable with both systems was 1.3 times larger at 3.0 T than that at 1.5 T. CONCLUSION: Functional 3.0-T MR imaging allows detection of additional activation in cortical areas involved in higher executive motor functions compared with functional 1.5-T MR imaging.

Adult↗
PubMed2005

Sensitivity encoding (SENSE) for contrast-enhanced 3D MR angiography of the abdominal arteries.

PURPOSE: To assess sensitivity encoding (SENSE) for contrast-enhanced MR angiography (CE-MRA) of the abdominal arteries in comparison with standard MRA protocols. MATERIALS AND METHODS: In 22 patients MRA of the abdominal arteries was performed twice (once using a standard protocol, and once with the additional use of SENSE). In 10 patients all examination parameters were kept constant (TR/TE/FA = 3.8 msec/1.3 msec/30 degrees ), and a reduction in scan time from 22 to 11 seconds was realized with the use of SENSE. In 12 patients, using SENSE the acquisition matrix was increased from 208 to 416, keeping the scan time constant. Image quality was scored on a five-point scale by three radiologists. Additionally, ROI-based measurements of CNR were performed. RESULTS: For both protocols, image quality was significantly improved using SENSE. The time-reducing SENSE protocol yielded an average score of 4.2 points vs. 3.1 for the standard protocol. Using SENSE to increase the acquisition matrix, an average score of 4.3 was reached vs. 3.2 for the standard protocol (P < 0.05). The number of depictable small vessels and their bifurcations was significantly increased by either of the two SENSE protocols as compared to the standard imaging procedure. CONCLUSION: SENSE for MRA of the abdominal arteries significantly increases image quality and permits a substantial reduction in breath-hold time or a significantly improved spatial resolution.

Abdomen↗
PubMed2005

Sensitivity encoding for diffusion-weighted MR imaging at 3.0 T: intraindividual comparative study.

PURPOSE: To prospectively evaluate whether diffusion-weighted (DW) magnetic resonance (MR) imaging with sensitivity encoding (SENSE) at 3.0 T can help to improve image quality and confidence in and accuracy of diagnosis of ischemic lesions, compared with DW MR imaging with conventional phase encoding, in patients. MATERIALS AND METHODS: Patients provided informed consent after the study had been explained, and the institutional review board approved the study protocol. Eighty-five patients (46 male and 39 female patients; age range, 13-86 years; mean age, 52 years) underwent single-shot spin-echo echo-planar DW MR imaging at 3.0 T twice, in a randomized order: once with conventional phase encoding (repetition time msec/echo time msec, 4283/79) and once with SENSE (3141/69, with a reduction factor of three). With both, 128 x 128 matrix, 24 4-mm-thick sections, and two b values of 0 and 1000 sec/mm(2) were used. An eight-element SENSE-compatible receive-only surface coil was used; the built-in body coil served for radiofrequency transmission and generation of the coil sensitivity profile. SENSE and conventional phase encoding were compared for image quality, signal-to-noise ratio, relative signal intensity (SI), and lesion contrast. Two neuroradiologists read images. Diagnostic accuracy of and confidence in detection of apparent diffusion coefficient (ADC) lesions with conventional phase encoding and SENSE at MR imaging were compared; matched-pairs Wilcoxon signed rank test was used to test statistical significance. RESULTS: No major SENSE-related artifacts were seen. At MR imaging with SENSE, consistently and significantly (P < .001) higher image quality scores were achieved because of substantial reduction of image distortions and blurring. Lesion contrast was equivalent with both techniques. Diagnostic confidence for demonstration and exclusion of lesions was significantly (P < .001) higher at MR imaging with SENSE. In three patients, small microembolic lesions were only prospectively diagnosed at MR imaging with SENSE, whereas they were masked by adjacent susceptibility effects and therefore overlooked at MR imaging with conventional phase encoding. CONCLUSION: Parallel MR imaging with SENSE is feasible at 3.0 T. It significantly improves image quality, particularly by reducing or even preventing susceptibility-induced SI changes and image blurring. There was a significantly improved diagnostic confidence with which ADC changes were identified or excluded.

Adolescent↗
PubMed2005

Dynamic bilateral contrast-enhanced MR imaging of the breast: trade-off between spatial and temporal resolution.

PURPOSE: To investigate prospectively the trade-off between temporal and spatial resolution in dynamic contrast material-enhanced bilateral magnetic resonance (MR) imaging of the breast. MATERIALS AND METHODS: Informed consent and institutional review board approval were obtained. An intraindividual comparative study was performed in 30 patients (mean age, 53 years; age range, 27-70 years) with a total of 54 enhancing lesions (28 benign and 26 malignant) who underwent dynamic MR imaging of the breast twice, once with a standard dynamic protocol (256 x 256 matrix, 69 seconds per acquisition) and once on a separate day with a modified dynamic protocol (400 x 512 matrix, 116 seconds per acquisition). Systematic qualitative analysis of morphologic features and region-of-interest-based analysis of enhancement kinetics were performed. RESULTS: A statistically significant difference (generalized linear modeling) in enhancement rates of benign versus malignant lesions was lost when moving from the standard to the modified dynamic protocol. Kinetic information on signal intensity time course patterns was preserved. Delineation of lesion margins and internal architecture was clearly superior with the modified dynamic protocol, which allowed identification of lesion features associated with high positive predictive value or high negative predictive value for breast cancer. Ten benign lesions classified as Breast Imaging Reporting and Data System (BI-RADS) category 3 with the standard protocol were correctly downgraded to BI-RADS category 2 with the modified protocol owing to visualization of internal septations. Thirteen malignant lesions categorized as BI-RADS category 3 or 4 with the standard protocol were correctly upgraded to BI-RADS category 4 or 5 with the modified protocol owing to visualization of spicules or rim enhancement. Receiver operating characteristic analysis revealed a significantly larger area under the curve for results obtained with the modified dynamic protocol. CONCLUSION: Increased spatial resolution significantly improves diagnostic confidence and accuracy at dynamic MR imaging, even if this improvement occurs at the expense of temporal resolution. Loss of kinetic information regarding enhancement rates proved to be not diagnostically relevant because enhancement rates showed broad overlap between benign and malignant lesions and were therefore of only limited diagnostic use in the individual patient. Kinetic information regarding time course pattern was preserved and confirmed as having high specificity and high positive predictive value.

Adult↗
PubMed2004

Acute and subacute ischemic stroke at high-field-strength (3.0-T) diffusion-weighted MR imaging: intraindividual comparative study.

PURPOSE: To compare signal-to-noise ratios (SNRs), contrast-to-noise ratios (CNRs), image quality, and confidence in diagnosis between 1.5- and 3.0-T diffusion-weighted (DW) magnetic resonance (MR) imaging of ischemic stroke lesions. MATERIALS AND METHODS: The study design was approved by the institutional review board, and all patients gave informed consent. In a prospective intraindividual study, 25 patients who had clinical symptoms consistent with ischemic stroke underwent DW MR imaging at both 1.5 T and 3.0 T. The 3.0- or 1.5-T examination was performed immediately one after the other, in random order. Two readers in consensus recorded the presence and number of ischemic lesions and rated image quality and lesion conspicuity. The image SNR and the CNR of the ischemic lesions were quantified. Paired Student t and Wilcoxon matched-pairs signed rank tests were used to test for statistical significance. RESULTS: Image quality at 3.0-T DW MR imaging was consistently lower than that at 1.5-T DW MR imaging owing to greater image distortions (P < .05). Yet, overall SNR and lesion CNR at 3.0 T increased significantly; mean increases were 48.8% (P < .001) and 96.3% (P < .01), respectively. The higher overall SNR and lesion CNR translated into a significantly higher sensitivity in the detection of ischemic lesions at 3.0 T than at 1.5 T. Of the total of 48 lesions that were identified in 19 of the 25 patients, 47 (98%) were diagnosed at 3.0 T and 36 (75%) were diagnosed at 1.5 T. In addition, the conspicuity of the lesions that were visible with both systems was significantly higher at 3.0 T (P < .001). CONCLUSION: Although 3.0-T DW MR imaging generates greater image distortions, it yields increased SNR and CNR compared with DW MR imaging at 1.5 T. The increased CNR at 3.0 T translates into a significantly improved diagnostic confidence in the detection of focal apparent diffusion coefficient changes in the setting of subacute and acute ischemic stroke.

Acute Disease↗
PubMed2004

Magnetic resonance imaging of the breast prior to biopsy.

CONTEXT: Breast magnetic resonance imaging (MRI) has been shown to have high sensitivity for cancer detection and is increasingly used following mammography to evaluate suspicious breast lesions. OBJECTIVE: To determine the accuracy of breast MRI in conjunction with mammography for the detection of breast cancer in patients with suspicious mammographic or clinical findings. DESIGN, SETTING, AND PATIENTS: Prospective multicenter investigation of the International Breast MR Consortium conducted at 14 university hospitals in North America and Europe from June 2, 1998, through October 31, 2001, of 821 patients referred for breast biopsy for American College of Radiology category 4 or 5 mammographic assessment or suspicious clinical or ultrasound finding. INTERVENTIONS: MRI examinations performed prior to breast biopsy; MRI results were interpreted at each site, which were blinded to pathological results. MAIN OUTCOME MEASURES: Area under the receiver operating characteristic curve (AUC), sensitivity, and specificity of breast MRI. RESULTS: Among the 821 patients, there were 404 malignant index lesions, of which 63 were ductal carcinoma in situ (DCIS) and 341 were invasive carcinoma. Of the 417 nonmalignant index lesions, 366 were benign, 47 showed atypical histology, and 4 were lobular carcinoma in situ. The AUC pooled over all institutions was 0.88 (95% confidence interval [CI], 0.86-0.91). MRI correctly detected cancer in 356 of 404 cancer cases (DCIS or invasive cancer), resulting in a sensitivity of 88.1% (95% CI, 84.6%-91.1%), and correctly identified as negative for cancer 281 of 417 cases without cancer, resulting in a specificity of 67.7% (95% CI, 62.7%-71.9%). MRI performance was not significantly affected by mammographic breast density, tumor histology, or menopausal status. The positive predictive values for 356 of 492 patients was 72.4% (95% CI, 68.2%-76.3%) and of mammography for 367 of 695 patients was 52.8% (95% CI, 49.0%-56.6%) (P<.005). Dynamic MRI did not improve the AUC compared with 3-dimensional MRI alone, but the specificity of a washout pattern for 123 of 136 patients without cancer was 90.4% (95% CI, 84%-95%). CONCLUSIONS: Breast MRI has high sensitivity but only moderate specificity independent of breast density, tumor type, and menopausal status. Although the positive predictive value of MRI is greater than mammography, MRI does not obviate the need for subsequent tissue sampling in this setting.

Adult↗
PubMed2003

Sensitivity encoding for fast MR imaging of the brain in patients with stroke.

PURPOSE: To evaluate sensitivity encoding (SENSE) technique in a clinical setting for magnetic resonance (MR) imaging in patients who are suspected of having infarction. MATERIALS AND METHODS: This intraindividual comparative study included 62 patients suspected of having cerebral ischemia. Patients underwent T2-weighted fluid-attenuated inversion-recovery (FLAIR) (n = 62), T2-weighted turbo spin-echo (TSE) (n = 48), and single-shot echo-planar diffusion-weighted imaging (n = 27) with standard sequential and SENSE MR acquisitions with a 1.5-T magnet and phased-array coil. With SENSE, acquisition time was reduced from 1 minute 12 seconds to 35 seconds for FLAIR and from 1 minute 18 seconds to 39 seconds for T2-weighted TSE imaging. For diffusion-weighted imaging, echo train length was shortened (78 vs 71 msec) to reduce susceptibility effects while acquisition time was maintained. Two radiologists scored quality of standard and SENSE images with a five-point scale and assessed presence of artifacts (motion, susceptibility) and lesion conspicuity. To assess statistical significance, Wilcoxon signed rank and chi2 tests were used. RESULTS: Statistical analysis revealed no significant difference in terms of image quality and presence of artifacts between standard and SENSE T2-weighted TSE (image quality, P =.724; presence of artifacts, P =.378) and FLAIR (image quality, P =.127; presence of artifacts, P =.275) images. Image quality at SENSE diffusion-weighted imaging was scored significantly higher compared with that at standard diffusion-weighted imaging (P =.002). Susceptibility artifacts were significantly reduced at SENSE diffusion-weighted imaging when compared with those at standard diffusion-weighted imaging (P <.001). Conspicuity of 84 lesions was rated equivalent with both standard and SENSE protocols. CONCLUSION: SENSE allowed acquisition of T2-weighted TSE and FLAIR images with image quality and lesion conspicuity that did not differ from those of standard acquisition techniques but in only half the acquisition time. Use of SENSE with diffusion-weighted imaging significantly reduces susceptibility artifacts while lesion conspicuity is maintained.

Adolescent↗
PubMed2003

Implications of SENSE MR in routine clinical practice.

Sensitivity encoding (SENSE) uses multiple MRI receive coil elements to encode spatial information in addition to traditional gradient encoding. Requiring less gradient encodings translates into shorter scan times, which is extremely beneficial in many clinical applications. SENSE is available to routine diagnostic imaging for the past 2 years. This paper highlights the use of SENSE with scan time reduction factors up to 6 in contrast-enhanced MRA, routine abdominal imaging, mammography, cardiac and neuro imaging. It is shown that SENSE has opened new horizons in both routine and advanced MR imaging.

Contrast Media↗
PubMed2002

Randomly segmented central k-space ordering in high-spatial-resolution contrast-enhanced MR angiography of the supraaortic arteries: initial experience.

Contrast material-enhanced three-dimensional (3D) magnetic resonance (MR) angiography of the supraaortic arteries with randomly segmented central k-space ordering (ie, contrast-enhanced timing-robust angiography [CENTRA]) was performed in 16 patients. CENTRA enabled reliable depiction of the aortic arch up to the circle of Willis at high spatial resolution (true voxel size, 0.81 x 0.81 x 1.0 mm(3)). With CENTRA, the divergent demands of high spatial resolution, wide anatomic coverage, and arterial phase imaging have been reconciled. The random order of central k-space acquisition may minimize artifacts in contrast-enhanced 3D MR angiography caused by unstable contrast material opacification at the initiation of sampling.

Adult↗