Cartilage T2 assessment at 3-T MR imaging: in vivo differentiation of normal hyaline cartilage from reparative tissue after two cartilage repair procedures--initial experience

PURPOSE: To prospectively compare cartilage T2 values after microfracture therapy (MFX) and matrix-associated autologous chondrocyte transplantation (MACT) repair procedures. MATERIALS AND METHODS: The study had institutional review board approval by the ethics committee of the Medical University of Vienna; informed consent was obtained. Twenty patients who underwent MFX or MACT (10 in each group) were enrolled. For comparability, patients of each group were matched by mean age (MFX, 40.0 years +/- 15.4 [standard deviation]; MACT, 41.0 years +/- 8.9) and postoperative interval (MFX, 28.6 months +/- 5.2; MACT, 27.4 months +/- 13.1). Magnetic resonance (MR) imaging was performed with a 3-T MR imager, and T2 maps were calculated from a multiecho spin-echo measurement. Global, as well as zonal, quantitative T2 values were calculated within the cartilage repair area and within cartilage sites determined to be morphologically normal articular cartilage. Additionally, with consideration of the zonal organization, global regions of interest were subdivided into deep and superficial areas. Differences between cartilage sites and groups were calculated by using a three-way analysis of variance. RESULTS: Quantitative T2 assessment of normal native hyaline cartilage showed similar results for all patients and a significant trend of increasing T2 values from deep to superficial zones (P < .05). In cartilage repair areas after MFX, global mean T2 was significantly reduced (P < .05), whereas after MACT, mean T2 was not reduced (P > or = .05). For zonal variation, repair tissue after MFX showed no significant trend between different depths (P > or = .05), in contrast to repair tissue after MACT, in which a significant increase from deep to superficial zones (P < .05) could be observed. CONCLUSION: Quantitative T2 mapping seems to reflect differences in repair tissues formed after two surgical cartilage repair procedures. (c) RSNA, 2008.

Durability and outcome of initial antiretroviral treatments received during 2000--2005 by patients in the Swiss HIV Cohort Study

BACKGROUND: Little is known about time trends, predictors, and consequences of changes made to antiretroviral therapy (ART) regimens early after patients initially start treatment. METHODS: We compared the incidence of, reasons for, and predictors of treatment change within 1 year after starting combination ART (cART), as well as virological and immunological outcomes at 1 year, among 1866 patients from the Swiss HIV Cohort Study who initiated cART during 2000--2001, 2002--2003, or 2004--2005. RESULTS: The durability of initial regimens did not improve over time (P = .15): 48.8% of 625 patients during 2000--2001, 43.8% of 607 during 2002--2003, and 44.3% of 634 during 2004--2005 changed cART within 1 year; reasons for change included intolerance (51.1% of all patients), patient wish (15.4%), physician decision (14.8%), and virological failure (7.1%). An increased probability of treatment change was associated with larger CD4+ cell counts, larger human immunodeficiency virus type 1 (HIV-1) RNA loads, and receipt of regimens that contained stavudine or indinavir/ritonavir, but a decreased probability was associated with receipt of regimens that contained tenofovir. Treatment discontinuation was associated with larger CD4+ cell counts, current use of injection drugs, and receipt of regimens that contained nevirapine. One-year outcomes improved between 2000--2001 and 2004--2005: 84.5% and 92.7% of patients, respectively, reached HIV-1 RNA loads of <50 copies/mL and achieved median increases in CD4+ cell counts of 157.5 and 197.5 cells/microL, respectively (P < .001 for all comparisons). CONCLUSIONS: Virological and immunological outcomes of initial treatments improved between 2000--2001 and 2004--2005, irrespective of uniformly high rates of early changes in treatment across the 3 study intervals.

Who should do NOTES? Initial endoscopic performance of laparoscopic surgeons compared to gastroenterologists and untrained individuals

INTRODUCTION: Natural orifice transluminal endoscopic surgery (NOTES) is a multidisciplinary surgical technique. If conventional endoscopic instrumentation can be easily mastered, surgeons with laparoscopic experience could head NOTES interventions. MATERIALS AND METHODS: Thirty individuals were tested for endoscopic dexterity. Group 1 included seven gastroenterologists, group 2 included 12 laparoscopically experienced surgeons lacking endoscopic experience, and group 3 included 11 interns who had no hands-on endoscopic or surgical experience. Each individual repeated an easy (T1), medium (T2), and difficult (T3) task ten times with endoscopic equipment on a NOTES skills-box. RESULTS: Group 3 had significantly poorer performances for all three tasks compared to the other groups. No significant differences were seen between groups 1 and 2 for T1 and T2. The initial T3 performance of group 1 was better than that of group 2, but their performance after repetition was not statistically different. Groups 2 and 3 improved significantly with repetition, and group 2 eventually performed as well as group 1. CONCLUSIONS: The data indicate that laparoscopic surgeons quickly learned to handle the endoscopic equipment. This suggests that a lack of endoscopic experience does not handicap laparoscopic surgeons when performing endoscopic tasks. Based on their knowledge of anatomy and the complication management acquired during surgical education, surgeons are well equipped to take the lead in interdisciplinary NOTES collaborations.

Cardioverter-defibrillator implantation in the catheterization laboratory: initial experiences in 48 patients

The exponential increase in cardioverter-defibrillator implantations has resulted in a need for safe implantations that do not require long waiting periods. We report intraoperative and follow-up results in 48 patients with ventricular tachyarrhythmias who underwent cardioverter-defibrillator implantation in the catheterization laboratory. Twenty-six (54%) patients had their first cardioverter-defibrillator implant (group 1), and 22 (46%) patients underwent pulse-generator replacement (group 2). In all patients, cardioverter-defibrillator implant or pulse-generator replacement was performed with the patient under general anesthesia. In 25 (96%) of 26 patients in group 1, cardioverter-defibrillator implantation was possible with a mean defibrillation threshold of 13 +/- 8 J. One patient had a defibrillation threshold of > 25 J, and therefore cardioverter-defibrillator implant was not achieved. This patient underwent epicardial device implantation 1 day later. Another patient in group 1 had vessel rupture (vena subclavia) intraoperatively. During a mean follow-up of 2 +/- 1 months, two patients died from congestive heart failure 2 and 4 months after device implantation. An infection occurred in one patient in group 2, 3 months after generator replacement. In conclusion, these data show that in the majority of patients cardioverter-defibrillator implantation in the catheterization laboratory is safe and has a low complication rate and therefore can generally be recommended.

Initial results of in vivo high-resolution morphological and biochemical cartilage imaging of patients after matrix-associated autologous chondrocyte transplantation (MACT) of the ankle

OBJECTIVE: The aim of this study was to use morphological as well as biochemical (T2 and T2* relaxation times and diffusion-weighted imaging (DWI)) magnetic resonance imaging (MRI) for the evaluation of healthy cartilage and cartilage repair tissue after matrix-associated autologous chondrocyte transplantation (MACT) of the ankle joint. MATERIALS AND METHODS: Ten healthy volunteers (mean age, 32.4 years) and 12 patients who underwent MACT of the ankle joint (mean age, 32.8 years) were included. In order to evaluate possible maturation effects, patients were separated into short-term (6-13 months) and long-term (20-54 months) follow-up cohorts. MRI was performed on a 3.0-T magnetic resonance (MR) scanner using a new dedicated eight-channel foot-and-ankle coil. Using high-resolution morphological MRI, the magnetic resonance observation of cartilage repair tissue (MOCART) score was assessed. For biochemical MRI, T2 mapping, T2* mapping, and DWI were obtained. Region-of-interest analysis was performed within native cartilage of the volunteers and control cartilage as well as cartilage repair tissue in the patients subsequent to MACT. RESULTS: The overall MOCART score in patients after MACT was 73.8. T2 relaxation times (approximately 50 ms), T2* relaxation times (approximately 16 ms), and the diffusion constant for DWI (approximately 1.3) were comparable for the healthy volunteers and the control cartilage in the patients after MACT. The cartilage repair tissue showed no significant difference in T2 and T2* relaxation times (p > or = 0.05) compared to the control cartilage; however, a significantly higher diffusivity (approximately 1.5; p < 0.05) was noted in the cartilage repair tissue. CONCLUSION: The obtained results suggest that besides morphological MRI and biochemical MR techniques, such as T2 and T2* mapping, DWI may also deliver additional information about the ultrastructure of cartilage and cartilage repair tissue in the ankle joint using high-field MRI, a dedicated multichannel coil, and sophisticated sequences.

Strangulation signs: initial correlation of MRI, MSCT, and forensic neck findings

PURPOSE: To evaluate multislice spiral computed tomography (MSCT) and magnetic resonance imaging (MRI) findings in hanging and manual strangulation cases and compare them with forensic autopsy results. MATERIALS AND METHODS: Postmortem MSCT and MRI of nine persons who died from hanging or manual strangulation were performed. The neck findings were compared with those discovered during forensic autopsy. In addition, two living patients underwent imaging and clinical examination following severe manual strangulation and near-hanging, respectively. For evaluation, the findings were divided into "primary" (strangulation mark and subcutaneous desiccation (i.e., soft-tissue thinning as a result of tissue fluids being driven out by mechanical compression) in hanging, and subcutaneous and intramuscular hemorrhage in manual strangulation) and "collateral" signs. The Wilcoxon two-tailed test was used for statistical analysis of the lymph node and salivary gland findings. RESULTS: In hanging, the primary and most frequent collateral signs were revealed by imaging. In manual strangulation, the primary findings were accurately depicted, with the exception of one slight hemorrhage. Apart from a vocal cord hemorrhage, all frequent collateral signs could be diagnosed radiologically. Traumatic lymph node hemorrhage (P = 0.031) was found in all of the manual strangulation cases. CONCLUSION: MSCT and MRI revealed strangulation signs concordantly with forensic pathology findings. Imaging offers a great potential for the forensic examination of lesions due to strangulation in both clinical and postmortem settings.

PET-CT-guided interventions in the management of FDG-positive lesions in patients suffering from solid malignancies: initial experiences

Positron emission tomography-computed tomography (PET-CT) has gained widespread acceptance as a staging investigation in the diagnostic workup of malignant tumours and may be used to visualize metabolic changes before the evolution of morphological changes. To make histology of PET findings without distinctive structural changes available for treatment decisions, we developed a protocol for multimodal image-guided interventions using an integrated PET-CT machine. We report our first experience in 12 patients admitted for staging and restaging of breast cancer, non-small cell lung cancer, cervical cancer, soft tissue sarcoma, and osteosarcoma. Patients were repositioned according to the findings in PET-CT and intervention was planned based on a subsequent single-bed PET-CT acquisition of the region concerned. The needle was introduced under CT guidance in a step-by-step technique and correct needle position in the centre of the FDG avid lesion was assured by repetition of a single-bed PET-CT acquisition before sampling. The metabolically active part of lesions was accurately targeted in all patients and representative samples were obtained in 92%. No major adverse effects occurred. We conclude that PET-CT guidance for interventions is feasible and may be promising to optimize the diagnostic yield of CT-guided interventions and to make metabolically active lesions without morphological correlate accessible to percutaneous interventions.

Cutting edge: Natalizumab blocks adhesion but not initial contact of human T cells to the blood-brain barrier in vivo in an animal model of multiple sclerosis

The humanized anti-alpha(4) integrin Ab Natalizumab is an effective treatment for relapsing-remitting multiple sclerosis. Natalizumab is thought to exert its therapeutic efficacy by blocking the alpha(4) integrin-mediated binding of circulating immune cells to the blood-brain barrier (BBB). As alpha(4) integrins control other immunological processes, natalizumab may, however, execute its beneficial effects elsewhere. By means of intravital microscopy we demonstrate that natalizumab specifically inhibits the firm adhesion but not the rolling or capture of human T cells on the inflamed BBB in mice with acute experimental autoimmune encephalomyelitis (EAE). The efficiency of natalizumab to block T cell adhesion to the inflamed BBB was found to be more effective in EAE than in acute systemic TNF-alpha-induced inflammation. Our data demonstrate that alpha(4) integrin-mediated adhesion of human T cells to the inflamed BBB during EAE is efficiently blocked by natalizumab and thus provide the first direct in vivo proof of concept of this therapy in multiple sclerosis.