Using a Dedicated Extremity MRI Scanner for Depicting Anatomic Structures of Common Wrist Pathologies: A Pilot Comparison with a 3-Tesla MRI Scanner.

Background This pilot study explored the value of a dedicated extremity magnetic resonance imaging (MRI) scanner by focusing on the qualitative depiction of important wrist structures in common wrist pathologies, the overall image quality, artifacts, and participant experience in undergoing the examinations. Methods Images of the right wrist of 10 healthy adult volunteers were acquired with a 0.31-Tesla (T) dedicated extremity MRI and a 3-T MRI system, using a dedicated wrist coil. Images were separately evaluated by three radiologists. Paired images were randomized and graded for the visibility of anatomical details, including the triangular fibrocartilage complex (TFCC; central disc, meniscus homolog, and ulnar attachment), carpal ligaments (scapholunate [SL] and lunotriquetral [LT] ligaments), intercarpal cartilage, and median and ulnar nerves. Mean values and standard deviations of evaluation results were calculated for each sequence. Participants' experience in undergoing the examination in both MRI scanners was explored using a questionnaire. Results The mean values of anatomic structures and overall image quality were significantly in favor of the 3-T MRI scanner, compared with the dedicated extremity MRI scanner. With respect to patient satisfaction in undergoing the examination, the overall trend suggested that patients were more in favor of the dedicated extremity MRI scanner. Conclusion For defining the real clinical value of the dedicated MRI scanner in the treatment of hand and wrist pathology, studies focused on pathologies are needed, which is certainly warranted, considering the important benefits of these devices including lower costs and higher accessibility for both patients and health care providers.

Dynamic contrast-enhanced and ultra-high-resolution breast MRI at 7.0 Tesla.

OBJECTIVE: To assess the feasibility of 7-T contrast-enhanced breast MRI in patients with suspicious masses. METHODS: Twenty patients with 23 suspicious breast masses on conventional imaging (mean size 13 mm, range 5-27 mm) were examined at 7 T. The MRI protocol included a dynamic series with injection of 0.1 mmol/kg gadobutrol (seven consecutive 3D T1-weighted gradient echo sequences, resolution 1 × 1 × 2 mm(3), temporal resolution 63 s) and ultra-high-resolution imaging (T1-weighted 3D gradient echo sequence, resolution 0.45 × 0.57 × 0.45 mm(3)). Two observers (R1 and R2) independently judged the examinations on image quality and classified lesions according to BI-RADS. The added value of ultra-high-resolution imaging was assessed. RESULTS: The image quality was deemed excellent in 1 and 0, good in 10 and 12, sufficient in 8 and 8, and insufficient in 1 and 0 for R1 and R2 respectively. Twenty of the 23 lesions were identified at 7-T MRI by both observers. All histopathologically proven malignant lesions (n = 19) were identified and classified as BI-RADS-MRI 4 or 5. Ultra-high-resolution imaging increased reader confidence in 88 % (R1) and 59 % (R2) of acquisitions. CONCLUSION: The study shows the feasibility of dynamic contrast-enhanced 7-T breast MRI, where all malignant mass lesions were identified by two observers. KEY POINTS: • Magnetic resonance imaging is important in the evaluation of breast cancer. • Recently, 7-T MRI has become available. • The 7-T dynamic contrast-enhanced breast MRI is feasible in patients. • The 7-T breast examinations are amenable to evaluation according to BI-RADS.

7 T versus 3T contrast-enhanced breast magnetic resonance imaging of invasive ductulolobular carcinoma: first clinical experience.

PURPOSE: Here we describe our first experience with contrast-enhanced (CE) MRI of breast cancer at 7 tesla (T), compared to 3T and histopathology. MATERIALS AND METHODS: A 52 year old female patient with a mammographically suspicious breast mass (BI-RADS V) underwent 7 T CE-MRI. Results were described according to the BI-RADS-MRI criteria and compared to 3T and histopathology. RESULTS: After contrast administration, a homogeneously enhancing, irregular spiculated mass was depicted at both 3T and 7 T; sizes were identical. The most malignant kinetic curve was characterized by a rapid initial rise followed by a wash-out pattern in the delayed phase, i.e. a type 3 curve, at both field strengths. Even though T1-effects of contrast agents are suggested to be reduced at higher fields, quantification of contrast enhancement-to-noise ratio showed a ratio of 4.6 at 7 T and 2.8 at 3T when comparing contrast-to-noise of the mass before and after contrast administration. Both examinations, using a single dose of gadolinium-based contrast agent, achieved good image quality. Final histopathological evaluation showed an invasive ductulolobular carcinoma with an intraductal component. CONCLUSION: This initial experience suggests that clinical contrast-enhanced 7 T MRI of the breast is technically feasible and may allow BI-RADS-conform analysis.

The value of 3.0-tesla MRI in diagnosing scapholunate ligament injury.

Objective To determine the sensitivity and specificity of 3.0-tesla (T) magnetic resonance imaging (MRI) and a dedicated hand coil in diagnosing scapholunate ligament (SLL) injury compared with intraoperative findings. Methods From January 2006 until September 2010, 3.0-T MRI scans were performed on 38 wrists (37 patients) with clinically unclear but suspected lesions of the SLL. These scans were evaluated by two experienced radiologists. Radiological findings were compared with intraoperative findings during arthrotomy. Sensitivity, specificity, accuracy, and positive and negative predictive value were calculated. Results An SLL lesion was identified during arthrotomy in 37 wrists. The first radiologist identified an SLL lesion on MRI in 26 wrists, all of which were confirmed intraoperatively. The second radiologist identified SLL lesions in 31 patients; however, intraoperatively it was found that there was no lesion of the ligament in one patient. Sensitivity ranged from 70 to 81% with a specificity of 100% and a positive predictive value of 97 to 100%. Accuracy measured 71 to 79%. Conclusions 3.0-T MRI of the wrist is moderately sensitive and very specific for detection of SLL lesions. However, if there is a high clinical suspicion of an SLL rupture, a 3.0-T MRI does not often have an additional value. Level of Evidence Diagnostic, level II.

Quantitative 31P magnetic resonance spectroscopy of the human breast at 7 T.

This study presents quantified levels of phosphorylated metabolites in glandular tissue of human breast using (31)P magnetic resonance spectroscopy at 7 T. We used a homebuilt (1)H/(31)P radiofrequency coil to obtain artifact-free (31)P MR spectra of glandular tissue of healthy females by deploying whole breast free induction decay (FID) detection with adiabatic excitation and outer volume suppression. Using progressive saturation, the estimated apparent T(1) relaxation time of (31)P spins of phosphocholine and phosphoethanolamine was 4.4 and 5.7 s, respectively. Quantitative measures for phosphocholine and phosphoethanolamine levels in glandular tissue were established based on MR imaging. We used a 3D (1)H image of the breast to segment the glandular tissue; this was matched to a 3D (31)P image of the B1- field of the (31)P coil to correct for differences in glandular tissue volume and B(1) inhomogeneity of the (31)P coil. The (31)P MR spectra were calibrated using a phantom with known concentration. Average levels of phosphocholine and phosphoethanolamine in 11 volunteers were 0.84 ± 0.21 mM and 1.18 ± 0.41 mM, respectively. In addition, data of three patients with breast cancer showed higher levels of phosphocholine and phosphoethanolamine compared with healthy volunteers. This may indicate a potential role for the use of (31)P magnetic resonance spectroscopy for characterization, prognosis, and treatment monitoring in breast cancer.

Investigation of lipid composition of dissected sentinel lymph nodes of breast cancer patients by 7T proton MR spectroscopy.

PURPOSE: To determine lipid composition of excised healthy and metastatic sentinel lymph nodes of breast cancer patients, as lipids are a potential discriminatory marker for malignancy. MATERIALS AND METHODS: Ten breast cancer patients undergoing surgical nodal staging were included. (1)H-magnetic resonance spectroscopic images (MRSI) were acquired without water and lipid suppression (resolution 3.0 × 3.0 × 5.0 mm(3)). MRSI was compared to histopathology. Six groups of lipid resonances (5.4-5.2, 4.3-4.1, 2.8, 2.3-2.0, 1.6-1.3, 0.9 ppm) were identified. The intensity ratios of the total of these resonances to this total including the water resonance and of each lipid resonance to the total of all lipid resonances were determined. For statistical analysis, a mixed model was applied after logistic transformation. The results were expressed as ratios of the median values of these lipid compositions in metastatic to benign nodes. RESULTS: In all, 6/32 (19%) of the excised nodes contained metastases. The ratios of the lipid resonances 5.4-5.2, 4.3-4.1, 2.8, 2.3-2.0, 1.6-1.3, 0.9 ppm between metastatic vs. benign were 0.3, 1.2, 0.2, 0.2, 1.2, and 0.9, respectively. Only the ratios of signals from unsaturated fatty acids to the total lipid signal differed significantly. CONCLUSION: Metastatic axillary lymph nodes contained fewer unsaturated fatty acids than benign nodes. 7T (1)H-MRS may be useful for detecting axillary breast cancer metastases.

Dissected sentinel lymph nodes of breast cancer patients: characterization with high-spatial-resolution 7-T MR imaging.

PURPOSE: To investigate the association of 7-T magnetic resonance (MR) imaging characteristics with metastatic nodal invasion, determined with histopathologic assessment in dissected sentinel lymph nodes of breast cancer patients. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. From November 2008 to July 2010, 114 dissected lymph nodes from 33 women (mean age, 57 years; range, 31-80 years) with breast cancer were included. For morphological analysis, three-dimensional (3D) T1-weighted fat-suppressed fast field- (gradient-) echo (isotropic resolution, 180 µm) MR was performed; 3D nodal dimensions, maximum cortical thickness, and presence of fatty hilum were noted. For quantitative parametric analysis, two-dimensional T1-weighted and 3D T2-, T2*-, and diffusion-weighted images were acquired. Statistical analysis included generalized estimating equations (GEEs), forward and backward stepwise regression analyses, and calculation of positive predictive value (PPV) and negative predictive value (NPV). RESULTS: Of 114 nodes, 26 (23%) were malignant. Morphological criteria showed weak discriminatory power: A fatty center was absent in 35% of malignant nodes and 30% of benign nodes (P = .9). Nodal volume and length-width ratio were not significantly different (P = .11 and .75, respectively). Cortical thickness (threshold level, 3 mm; P = .02) showed 91% NPV for malignancy and 95% NPV for presence of macrometastases. Quantitative parametric analyses showed comparable mean T1, T2, and T2* relaxation time constants and apparent diffusion coefficient for metastatic and benign nodes: 991 msec, 30 msec, and 18 msec and 0.17 mm²/sec versus 1035 msec (P = .14), 31 msec (P = .001; not significant after GEE), and 15 msec (P = .002) and 0.20 mm²/sec (P = .38), respectively. Mean T2* alone offered an additive discriminatory effect for identification of metastatic nodes. Consistent with the notion of pannodal changes accompanying tumor infiltration, mean T2* differed significantly even if only micrometastases were present. The interindividual differences were small, precluding easy clinical implementation. CONCLUSION: Morphological criteria showed poor discriminatory power, even with very-high-spatial-resolution imaging. T2* quantification allowed identification of metastatic nodal invasion.

31P MRSI and 1H MRS at 7 T: initial results in human breast cancer.

This study demonstrates the feasibility of the noninvasive determination of important biomarkers of human (breast) tumor metabolism using high-field (7-T) MRI and MRS. (31) P MRSI at this field strength was used to provide a direct method for the in vivo detection and quantification of endogenous biomarkers. These encompass phospholipid metabolism, phosphate energy metabolism and intracellular pH. A double-tuned, dual-element transceiver was designed with focused radiofrequency fields for unilateral breast imaging and spectroscopy tuned for optimized sensitivity at 7 T. T(1) -weighted three-dimensional MRI and (1) H MRS were applied for the localization and quantification of total choline compounds. (31) P MRSI was obtained within 20 min per subject and mapped in three dimensions over the breast with pixel volumes of 10 mL. The feasibility of monitoring in vivo metabolism was demonstrated in two patients with breast cancer during neoadjuvant chemotherapy, validated by ex vivo high-resolution magic angle spinning NMR and compared with data from an age-matched healthy volunteer. Concentrations of total choline down to 0.4 mM could be detected in the human breast in vivo. Levels of adenosine and other nucleoside triphosphates, inorganic phosphate, phosphocholine, phosphoethanolamine and their glycerol diesters detected in glandular tissue, as well as in tumor, were mapped over the entire breast. Altered levels of these compounds were observed in patients compared with an age-matched healthy volunteer; modulation of these levels occurred in breast tumors during neoadjuvant chemotherapy. To our knowledge, this is the first comprehensive MRI and MRS study in patients with breast cancer, which reveals detailed information on the morphology and phospholipid metabolism from volumes as small as 10 mL. This endogenous metabolic information may provide a new method for the noninvasive assessment of prognostic and predictive biomarkers in breast cancer treatment.

Feasibility of 7 Tesla breast magnetic resonance imaging determination of intrinsic sensitivity and high-resolution magnetic resonance imaging, diffusion-weighted imaging, and (1)H-magnetic resonance spectroscopy of breast cancer patients receiving neoadjuvant therapy.

OBJECTIVES: To evaluate the feasibility of 7T breast magnetic resonance imaging (MRI) by determining the intrinsic sensitivity gain compared with 3T in healthy volunteers and to explore clinical application of 7T MRI in breast cancer patients receiving neoadjuvant chemotherapy (NAC). MATERIALS AND METHODS: In 5 volunteers, the signal-to-noise ratio (SNR) was determined on proton density MRI at 3T using a conventional 4-channel bilateral breast coil and at 7T using a dedicated 2-channel unilateral breast coil, both obtained at identical scan parameters. Subsequently, consecutive breast cancer patients on NAC were included. The 7T breast MRI protocol consisted of diffusion-weighted imaging, 3D high-resolution (450 µm isotropic) T1-weighted fat-suppressed gradient-echo sequences and quantified single voxel (1)H-magnetic resonance spectroscopy. Morphology was scored according to the MRI Breast Imaging-Reporting and Data System (BI-RADS)-lexicon, and the images were compared with 3T and histopathologic findings. Image quality was evaluated using a 5-point scale. RESULTS: A 5.7-fold higher SNR was measured at 7T than at 3T, which reflects the advantages of a higher field strength and the use of optimized radiofrequency coils. Three breast cancer patients were included and received a total of 13 7T MRI examinations. The image quality of the high-resolution examinations was at least satisfactory, and good to excellent in 9 of the 13 examinations performed. More anatomic detail was depicted at 7T than at 3T. In 1 case, a fat plane between the muscle and tumor was visible at 7T, but not at the clinically performed 3T examination, suggesting that there was no muscle invasion, which was confirmed by pathology. Changes in tumor apparent diffusion coefficient values could be monitored in 2 patients and were found to increase during NAC, consistent with published results from studies at lower field strengths. Apparent diffusion coefficient values increased respectively from 0.33 × 10(-3) mm(2)/s to 1.78 × 10(-3) mm(2)/s after NAC and from 1.20 × 10(-3) mm(2)/s to 1.44 × 10(-3) mm(2)/s during NAC. Choline concentrations as low as 0.77 mMol/kg(water) could be detected. In 1 patient, choline levels showed an overall decrease from 4.2 mMol/kw(water) to 2.6 mMol/kg(water) after NAC and the tumor size decreased correspondingly from 3.9 × 4.1 × 5.6 cm(3) to 2.0 × 2.7 × 2.4 cm(3). All 7T MRI findings were consistent with pathology analysis. CONCLUSION: Dedicated 7T breast MRI is technically feasible, can provide more SNR than at 3T, and has diagnostic potential.

Cryoplasty for occlusive disease of the femoropopliteal arteries: 1-year follow-up.

Atherosclerosis of femoropopliteal arteries is an important cause of morbidity and mortality. Percutaneous transluminal angioplasty (PTA) has only limited success in treating these arteries, mainly because of the high rate of recurrent stenosis. Cryoplasty has been proposed as a technique which might improve treatment outcome. This study reports our single-center experience with cryoplasty. Thirty-two claudicants, 33 arteries, in whom conservative therapy failed, were consecutively included. Duplex ultrasound (US), angiography, and ankle-brachial index (ABI) measurement were performed before the procedure; ABI and duplex US, 2 weeks and 3, 6, and 12 months after the procedure. Patients' symptoms were categorized according to the Rutherford classification. Lesions were classified as TASC A, B, or C according to angiographic appearance. Differences in ABI before and after the procedure were defined as significant at p < 0.05 by paired t-test. Patency was evaluated using duplex US by determining the peak systolic velocity ratio. Sixteen TASC A lesions, 13 TASC B lesions, and 4 TASC C lesions were included. ABI improved significantly for TASC A lesions 2 weeks and 3 months postprocedure. Patency after 2 weeks, 6 months, and 12 months was 93%, 67%, and 64% for TASC A lesions, 83%, 31%, and 31% for TASC B lesions, and 100%, 50%, and 33% for TASC C lesions, respectively. In conclusion, cryoplasty has good immediate success rates and patency rates similar to the results of conventional PTA in the literature.