Comparison of autograft and allograft aortic valve replacement in children

OBJECTIVE: This study was undertaken to compare the clinical and hemodynamic results following aortic valve replacement with a pulmonary valve autograft (Ross procedure) or an allograft valve in children. METHODS: The records of 107 pediatric aortic valve replacements from 1994 through 2001 were reviewed, including 78 autografts and 25 allografts. Four mechanical aortic valve replacements performed during this period were excluded from analysis. RESULTS: There were 3 perioperative deaths and 1 late death. Reoperations were required in 5 autograft recipients (with autograft preservation in 4) and in 3 allograft recipients (all requiring valve re-replacement). Seven-year survival (96% in both groups) and reoperation-free survival (88% in the autograft group; 73% in the allograft group, P =.5) were not significantly different. Serial echocardiographic studies showed that in the autograft group, left ventricular outflow tract maximal velocity (2.0-1.8 m/s, P =.02) and left ventricular thickness (10.1-8.4 mm, P <.0001) fell significantly. In the allograft group, maximal velocity (2.3-3.0 m/s, P =.03) increased significantly and left ventricular thickness (9.5-9.0 mm, P =.2) showed minimal change. Analysis according to preoperative physiology (aortic stenosis versus insufficiency), congenital cardiac anatomy, number or type of previous operations, age of patient, and use of balloon valvotomy did not predict outcomes. CONCLUSIONS: Aortic valve replacement with either the autograft or allograft provides excellent clinical results in children during an intermediate duration of observation. The Ross procedure achieves a superior hemodynamic result, which may be clinically important with longer follow-up.     

Phase II study of abarelix depot for androgen independent prostate cancer progression during gonadotropin-releasing hormone agonist therapy

PURPOSE: We determine the clinical efficacy of the gonadotropin-releasing hormone (Gn-RH) antagonist abarelix in patients with androgen independent prostate cancer, and measure its effect on serum follicle-stimulating hormone (FSH) and testosterone. MATERIALS AND METHODS: A total of 20 patients with prostate cancer progression during Gn-RH agonist therapy received 100 mg. abarelix depot by intramuscular injection on days 1, 15 and 29, and then every 28 days for up to 24 weeks. Gn-RH agonist therapy was not continued. Patients who met criteria for prostate specific antigen (PSA) response after 24 weeks of therapy could receive treatment for up to 52 weeks. PSA response was the primary end point and was defined as a 50% decrease confirmed 4 weeks later. Secondary end points of this study were the effect of therapy on serum FSH and testosterone. RESULTS: No patient met the criteria for PSA response. At the end of the 6 cycles of therapy 2 patients remained stable without PSA progression or other signs of disease progression. Median time to progression was 8 weeks (95% CI 5.7-10.3). Mean serum FSH decreased by more than 50% from a baseline of 5.7 IU/l. (95% CI 4.2-7.1) and remained suppressed throughout the observation period. Mean serum testosterone did not change after 4 and 8 weeks of therapy and remained in the anorchid range. Treatment was well tolerated with no grade 3 or higher toxicity. CONCLUSIONS: Treatment of androgen independent prostate cancer with abarelix decreases circulating FSH and maintains anorchid testosterone but does not result in clinical responses.     

Rapid 3D-T(1) mapping of cartilage with variable flip angle and parallel imaging at 3.0T

PURPOSE: To rapidly acquire T(1)-weighted images using a three-dimensional fast low angle shot (3D FLASH) sequence in combination with generalized autocalibrating partially parallel acquisitions (GRAPPA) and variable flip angle (VFA) method at 3.0T. MATERIALS AND METHODS: 3D T(1) maps of model systems (gadolinium [Gd] and agarose phantoms), bovine cartilage, and human subjects were constructed on a 3.0T clinical whole-body MR scanner. The T(1) values of model systems measured using the 2D inversion-recovery fast-spin-echo (IR-FSE) sequence were considered as a reference method to validate the rapid 3D method for comparison. RESULTS: The root mean square coefficient of variation percentage (RMS-CV%) of the median T(1) of agarose phantom across different acquisition methods was approximately 6.2%. The RMS-CV% of the median T(1) of bovine cartilage across different acquisition methods was approximately 4.1%. The RMS-CV% of median T(1) of the cartilages among the subjects was between approximately 7.3% to 11.1%. In our study, rapid 3D-T(1) mapping with VFA and parallel imaging with different acceleration factors (AFs) (AF = 1, 2, 3, and 4) seems to have no obvious influence on the T(1) mapping (before and after contrast agent administration). CONCLUSION: The preliminary results demonstrate that it is possible to quantify 3D-T(1) mapping of the whole knee joint (with 0.7 mm(3) isotropic resolution) under approximately five minutes with excellent in vivo reproducibility at 3.0T.     

Breast conservation surgery and interstitial brachytherapy in the management of locally recurrent carcinoma of the breast: the Allegheny General Hospital experience

PURPOSE: To evaluate lumpectomy followed by interstitial brachytherapy as an acceptable salvage therapy for women who have developed localized recurrence of breast cancer after conservation surgery and postoperative external radiotherapy. METHODS AND MATERIALS: Between 1/1998 and 10/2006, 21 patients with T0 or T1 in-breast recurrence of carcinoma were offered interstitial low-dose rate brachytherapy after tumor re-excision as an alternative to salvage mastectomy. All patients had failed lumpectomy followed by standard postoperative external beam radiotherapy (range, 5000-6040cGy) as treatment for the initial breast carcinoma. Seven recurred as ductal carcinoma in situ, 2 as infiltrating lobular carcinoma, and 12 as recurrent invasive carcinoma. The recurrent tumors were excised with final margins of resection free of residual disease per National Surgical Adjuvant Breast and Bowel Project definition. Tumor bed implantation was then carried out with an interstitial technique using (192)Ir with the target volume consisting of the tumor bed plus a minimum 1.0-cm clinical margin. The required minimum dose delivered to the target volume was 4500-5000cGy (range, 4500-5530). RESULTS: Twenty of 21 patients were free of local disease with a median observation time of 40 months (range, 3-69). The single patient who developed a second local recurrence was treated successfully with simple mastectomy. Two patients succumbed to systemic disease at 17 and 24 months after salvage implant therapy. One patient developed a contralateral breast cancer. Cosmetic results defined by the National Surgical Adjuvant Breast and Bowel Project cosmesis scale were acceptable. One patient developed a localized seroma requiring multiple needle aspirations before complete resolution. Two patients developed localized skin breakdown in the tumor bed. One healed after 6 months of conservative treatment. The other healed 9 months later with Grade II cosmesis. This patient also developed a concurrent postoperative wound infection. CONCLUSIONS: Repeat lumpectomy followed by brachytherapy is feasible and may be an acceptable alternative to salvage mastectomy in patients who locally fail conservation breast therapy; however, longer followup and greater patient numbers may be needed to better define the role of salvage brachytherapy.     

Reconstruction of undersampled non-Cartesian data sets using pseudo-Cartesian GRAPPA in conjunction with GROG.

Most k-space-based parallel imaging reconstruction techniques, such as Generalized Autocalibrating Partially Parallel Acquisitions (GRAPPA), necessitate the acquisition of regularly sampled Cartesian k-space data to reconstruct a nonaliased image efficiently. However, non-Cartesian sampling schemes offer some inherent advantages to the user due to their better coverage of the center of k-space and faster acquisition times. On the other hand, these sampling schemes have the disadvantage that the points acquired generally do not lie on a grid and have complex k-space sampling patterns. Thus, the extension of Cartesian GRAPPA to non-Cartesian sequences is nontrivial. This study introduces a simple, novel method for performing Cartesian GRAPPA reconstructions on undersampled non-Cartesian k-space data gridded using GROG (GRAPPA Operator Gridding) to arrive at a nonaliased image. Because the undersampled non-Cartesian data cannot be reconstructed using a single GRAPPA kernel, several Cartesian patterns are selected for the reconstruction. This flexibility in terms of both the appearance and number of patterns allows this pseudo-Cartesian GRAPPA to be used with undersampled data sets acquired with any non-Cartesian trajectory. The successful implementation of the reconstruction algorithm using several different trajectories, including radial, rosette, spiral, one-dimensional non-Cartesian, and zig-zag trajectories, is demonstrated.     

Transosseous arthroscopic repair of partial articular-surface supraspinatus tendon tears

Partial articular-surface tendon avulsion (PASTA) lesions of the supraspinatus muscle represent a common cause for shoulder impairment and a preceding pathology for full-thickness tendon tears. Arthroscopic tendon repair is a possible surgical method of treatment. The purposes of cuff repair are anatomical tendon healing, prevention of tear size progression to completion and reduction of shoulder pain. In this report, we describe a transtendon arthroscopic technique of transosseous refixation of articular-side partial tears leaving the bursal layer of the supraspinatus tendon intact. A curved hollow needle is used to perform an all arthroscopic transosseous mattress suture. Thus, anatomical tendon-to-bone contact of the rotator cuff to the footprint is restored. Preliminary clinical results of 16 patients are convincing with significant pain relief and functional improvement.     

Adaptations in trabecular bone microarchitecture in Olympic athletes determined by 7T MRI

PURPOSE: To produce in vivo high-resolution images of the knee and to determine the feasibility of using 7T MR to detect changes in trabecular bone microarchitecture in elite athletes (Olympic fencers) who undergo high impact activity. MATERIALS AND METHODS: The dominant knees of four males from the U.S. Olympic Fencing Team and three matched healthy male controls were scanned in a 7T whole-body scanner using a quadrature knee coil with three-dimensional (3D) fast low angle shot (FLASH): 50 axial images at the distal femur (0.156 mm x 0.156 mm) and 80 axial images at the knee joint (0.195 mm x 0.195 mm). Bone volume fraction (BVF) and marrow volume fraction (MVF) images were computed and fuzzy distance transform (FDT) and digital topological analysis (DTA) were applied to determine: trabecular number (Tb.N), trabecular thickness (Tb.Th), and trabecular separation (Tb.Sp); BVF (BV/TV); trabecular and marrow space surface-to-curve ratio (SC, marker of plate to rod ratio); and trabecular and marrow space erosion index (EI, inverse marker for network connectivity). Quadriceps muscle volume (MV) was calculated as well. We calculated group means and performed two-tailed t-tests to determine statistical significance. RESULTS: Compared to controls, fencers had: decreased Tb.Sp (P = 0.0082 at femur, P = 0.051 at joint); increased Tb.N (P < 0.05 at both femur and joint) and BV/TV (P < 0.001 at both femur and joint); increased trabecular SC and decreased marrow space SC (P < 0.01 at both femur and joint); decreased trabecular EI and increased marrow space EI (P < 0.01 at both femur and joint); and increased MV (P = 0.038). There was no difference in Tb.Th at the distal femur (P = 0.92) or joint (P = 0.71) between groups. CONCLUSION: To our knowledge, this is the first study to perform 7T MRI of the knee in vivo. Elite athletes who undergo high impact activity have increased MV and improved trabecular bone structure compared to controls.     

Prostate MR imaging at 3T with a longitudinal array endorectal surface coil and phased array body coil

PURPOSE: To demonstrate the feasibility of using a double loop phased array endorectal coil combined with a phased array body coil to image the prostate at 3T. MATERIALS AND METHODS: We designed and constructed a novel prostate coil employing two arrayed 4.0 x 5.0 cm loops, tuned the device for optimal performance at 3T, and characterized the signal-to-noise ratio (SNR) associated with it. RESULTS: The coil Q factor was calculated to be approximately 50 unloaded, and 30 when loaded on human tissue. SNR maps at multiple orientations were constructed and images were acquired on both a phantom and a human. As expected, SNR was highest along the midpoint of the array and demonstrated strong signal even at 4 cm from the coil. CONCLUSION: The double loop phased array endorectal coil combined with a phased array body coil at 3T is feasible in vivo and compelling enough to warrant future clinical trials to evaluate its efficacy. These trials are currently under way.     

MR-guided liver biopsy within a short, wide-bore 1.5 Tesla MR system

The purpose of this study was to evaluate the diagnostic efficacy of magnetic resonance (MR)-guided biopsy of focal liver lesions within a short, wide-bore 1.5-T MR system and to determine the duration and accuracy of needle placement using MR fluoroscopy guidance in 25 patients. Accuracy of needle placement was evaluated in two orthogonal planes, and the out-of-plane angle of needle deflection was measured. Needle positioning was characterised subjectively as centred, peripheral, or exterior relative to the lesion. Exterior positioning was corrected by a step-by-step procedure. Surgical resection (n = 6), previous histologies (n = 8), or clinical/radiological follow-up (n = 11) served as the ‘gold standard’. The guidance needle could be placed successfully using MR fluoroscopy in 20 of 25 patients (80%). Needle placement was rated as ‘centred’ in 11 and as ‘peripheral’ in nine patients. Median needle deflection was 2.6 degrees, with a median deviation of 3.4 mm. In five patients, the direct approach failed or was rated as ‘exterior’; therefore, repositioning after needle stabilisation with a stainless-steel stylet was necessary. The diagnostic yield of all biopsies was: sensitivity 95.5%, specificity 100.0% and accuracy 96.0%. In conclusion, MR-guided biopsies in a short, wide-bore MR system yielded highly reliable biopsy results, and in most cases the direct approach with MR fluoroscopy guidance proved to be fast and accurate.     

Breast tomosynthesis and digital mammography: a comparison of breast cancer visibility and BIRADS classification in a population of cancers with subtle mammographic findings

The main purpose was to compare breast cancer visibility in one-view breast tomosynthesis (BT) to cancer visibility in one- or two-view digital mammography (DM). Thirty-six patients were selected on the basis of subtle signs of breast cancer on DM. One-view BT was performed with the same compression angle as the DM image in which the finding was least/not visible. On BT, 25 projections images were acquired over an angular range of 50 degrees, with double the dose of one-view DM. Two expert breast imagers classified one- and two-view DM, and BT findings for cancer visibility and BIRADS cancer probability in a non-blinded consensus study. Forty breast cancers were found in 37 breasts. The cancers were rated more visible on BT compared to one-view and two-view DM in 22 and 11 cases, respectively, (p < 0.01 for both comparisons). Comparing one-view DM to one-view BT, 21 patients were upgraded on BIRADS classification (p < 0.01). Comparing two-view DM to one-view BT, 12 patients were upgraded on BIRADS classification (p < 0.01). The results indicate that the cancer visibility on BT is superior to DM, which suggests that BT may have a higher sensitivity for breast cancer detection.