Impact of cardiac reverse remodeling after cardiac resynchronization therapy assessed by myocardial perfusion imaging on ventricular arrhythmia.

BACKGROUND: Although cardiac resynchronization therapy (CRT) has been a useful treatment of heart failure, patients with CRT are still in risk of sudden cardiac death due to ventricular arrhythmia. The aim of this study was to investigate the impact of cardiac reverse remodeling after CRT on the prevalence of ventricular tachycardia or fibrillation (VT/VF). METHODS AND RESULTS: Forty-one heart failure patients (26 men, age 66 ± 10 years), who were implanted with CRT for at least 12 months, were enrolled. All patients received myocardial perfusion imaging (MPI) under CRT pacing to evaluate left ventricle (LV) function, dyssynchrony, and scar. VT/VF episodes during the follow-up period after MPI were recorded by the CRT devices. Sixteen patients (N = 16/41, 39%) were found to have VT/VF. Multivariate Cox regression analysis and receiver operating characteristic curve analysis showed that five risk factors were significant predictors of VT/VF, including increased left ventricle ejection fraction (LVEF) by ≤7% after CRT, low LVEF after CRT (≤30%), change of intrinsic QRS duration (iQRSd) by ≤7 ms, wide iQRSd after CRT (≥121 ms), and high systolic dyssynchrony after CRT (phase standard deviation ≥45.6°). For those patients with all of the 5 risk factors, 85.7% or more developed VT/VF. CONCLUSIONS: The characteristics of cardiac reverse remodeling after CRT as assessed by MPI are associated with the prevalence of ventricular arrhythmia.

Impact of right-ventricular apical pacing on the optimal left-ventricular lead positions measured by phase analysis of SPECT myocardial perfusion imaging.

PURPOSE: The use of SPECT phase analysis to optimize left-ventricular (LV) lead positions for cardiac resynchronization therapy (CRT) was performed at baseline, but CRT works as simultaneous right ventricular (RV) and LV pacing. The aim of this study was to assess the impact of RV apical (RVA) pacing on optimal LV lead positions measured by SPECT phase analysis. METHODS: This study prospectively enrolled 46 patients. Two SPECT myocardial perfusion scans were acquired under sinus rhythm with complete left bundle branch block and RVA pacing, respectively, following a single injection of (99m)Tc-sestamibi. LV dyssynchrony parameters and optimal LV lead positions were measured by the phase analysis technique and then compared between the two scans. RESULTS: The LV dyssynchrony parameters were significantly larger with RVA pacing than with sinus rhythm (p ~0.01). In 39 of the 46 patients, the optimal LV lead positions were the same between RVA pacing and sinus rhythm (kappa = 0.861). In 6 of the remaining 7 patients, the optimal LV lead positions were along the same radial direction, but RVA pacing shifted the optimal LV lead positions toward the base. CONCLUSION: The optimal LV lead positions measured by SPECT phase analysis were consistent, no matter whether the SPECT images were acquired under sinus rhythm or RVA pacing. In some patients, RVA pacing shifted the optimal LV lead positions toward the base. This study supports the use of baseline SPECT myocardial perfusion imaging to optimize LV lead positions to increase CRT efficacy.

Therapeutic efficacy of 188Re-MN-16ET lipiodol in an animal model of hepatocellular carcinoma.

OBJECTIVE: In our recent study, we developed a new radiopharmaceutical (Re-188 MN-16ET lipiodol) with encouraging results for the treatment of liver malignancy. In this study, we further evaluated the therapeutic efficacy of this radiopharmaceutical by measuring tumor response and survival times in rats with liver tumors after intra-hepatic arterial injection of Re-188 MN-16ET lipiodol. METHODS: Twelve male rats bearing hepatic tumors were divided into three groups. Group 1 received an intra-hepatic arterial injection of 18.5 MBq Re-188 MN-16ET lipiodol; Group 2 received lipiodol and Group 3 received normal saline. Tumor size was measured by liver sonography before injection, at 2, 4, and 8 weeks after injection. Survival time and response rate were calculated. RESULTS: All rats showed good response and survived over 60 days in Group 1 while all rats showed poor response in Group 2 and Group 3 with only 25 % of rats in Group 2 and none (0 %) in Group 3 survived over 60 days. The p value was 0.0067 between Group 1 and Group 3; 0.04 between Group 1 and Group 2; and 0.034 between Group 2 and Group 3. CONCLUSION: Re-188 MN-16ET lipiodol has good potential for the treatment of hepatoma.

A comparison of Re-188-MN-16ET-lipiodol and transcatheter arterial chemoembolization in the treatment of hepatoma: an animal study.

INTRODUCTION: In patients with unresectable HCC, transcatheter arterial chemoembolization (TACE) is a widely used treatment. Recently, as an alternative treatment modality for HCC, transcatheter arterial embolization with radioisotopes has been investigated. In this study, we compared the therapeutic efficacy of an intra-hepatic arterial injection of Re-188-MN-16ET-lipiodol and the TACE method in rats with liver tumors. METHODS: Twelve male rats bearing hepatic tumors were divided into three groups to evaluate the efficacy of treatment (four in each group). Group 1 received an intra-hepatic arterial injection of 0.2mCi of Re-188-MN-16ET-lipiodol; group 2 received epirubicin (0.5mg/kg) and 0.1ml of lipiodol emulsion; group 3 received 0.1ml of normal saline and served as the control group. Tumor size was measured by liver sonography before injection, at two weeks, four weeks and eight weeks after injection. Survival time was calculated from the day of treatment to 56days after treatment by the life-table method. The response to treatment and the survival time in each group were evaluated and compared. RESULTS: All rats treated with Re-188 MN-16ET-lipiodol showed good response to the therapy. Their tumor size decreased and all rats survived over eight weeks. All rats treated with epirubicin plus lipiodol survived over 8weeks; however, two rats (50%) showed increased tumor size in the 8th week. As for the control group (rats treated with normal saline), all rats survived less than 37days with continuous tumor growth. CONCLUSION: Results showed that Re-188-MN-16ET-lipiodol can be a potential therapeutic pharmaceutical for the treatment of liver tumors.

Unexpected accumulation of F-18 FDG in the urinary bladder after bladder irrigation and retrograde filling with sterile saline: a possible pitfall in PET examination.

BACKGROUND: : Bladder irrigation and retrograde filling technique has been used to reduce urinary F-18 FDG (FDG) activity for better image interpretation in patients with pelvic tumors. Despite the zealous use of this technique, FDG accumulation in the urinary bladder has been reported and might cause false-positive or false-negative results. In this study, we analyzed the pattern and estimated the incidence of the unexpected accumulation of urinary FDG activity after bladder irrigation and retrograde filling with sterile saline. METHODS: : We reviewed 53 patients with pelvic malignancies who underwent FDG-PET scans. All of them had bladder irrigation and retrograde filling with sterile saline via triple lumen Foley Catheters. If there was high FDG activity, either focal or diffuse, in the urinary bladder on the standard 1-hour image, bladder irrigation and retrograde filling were repeated and the delayed 3-hour images were acquired. If delayed 3-hour scanning was not possible due to time restraint or the patient's inability to cooperate, pelvic images were immediately acquired while the patient changed to the prone position. RESULTS: : On the 1-hour images, 43 of the 53 (81.1%) patients showed low urinary FDG activities and satisfactory image quality for interpretation. However, 10 (18.9%) patients had high FDG activity in the urinary bladder, which could interfere with pelvic image interpretation. Of these 10 patients, 3 (5.7%) patients had diffuse FDG activity in the urinary bladder, which could obliterate a nearby FDG-avid lesion. All of the diffuse urinary FDG activity was cleared with repeated bladder irrigation and retrograde filling. The remaining 7 (13.2%) patients had focal FDG-accumulation in the bladder, which might cause false-positive result. Five of them had repeated bladder irrigation and retrograde filling and all of the focal FDG-accumulations disappeared on the delayed images. Bladder irrigation and retrograde filling could not be performed in 2 patients and pelvic images were acquired after the patients changed to the prone position. The urinary FDG accumulation changed from the posterior portion of the bladder in the supine position to the anterior portion of the bladder in the prone position. CONCLUSION: : Unexpected FDG activity in the urinary bladder, either focal or diffuse, may occur after bladder irrigation and retrograde filling and interfere with pelvic image interpretation. Great caution is required to avoid misdiagnosis: focal FDG accumulation may mimic tumor uptake of FDG whereas diffuse FDG activity may obliterate a FDG-avid pelvic lesion. Repeated bladder irrigation and retrograde filling, and prone-position imaging are useful techniques to ascertain the nature of the FDG accumulation.

Infiltrating spinal angiolipoma.

Infiltrating angiolipomas are rarely encountered in the spine. We present a case involving a 71-year-old man with a dorsal epidural angiolipoma at the T5-T7 level. The tumor involved the T5-T6 vertebral bodies and left pedicle. The patient presented with acute paraparesis and MRI showed a homogeneously hyphointense lesion on T1-weighted images. The epidural component of the tumor was removed via laminectomy to achieve adequate cord decompression. The patient was symptom-free at a 2-year follow-up. This report emphasizes the unusual clinical presentation and MRI features of an infiltrating spinal angiolipoma and discusses therapeutic management options.

Highly efficient and recyclable Au nanoparticle-supported palladium(II) interphase catalysts and microwave-assisted alkyne cyclotrimerization reactions in ionic liquids.

The gold nanoparticles with core diameter of 3.9-4.7 nm were stabilized with octanethiolate and dipyridylphosphinicamido undecanethiolate. Without varying the size of central Au cores, palladium complexes were immobilized onto these Au nanoparticles through chelation to the surface-bound dipyridyls. Hybrid catalysts of this type were dissolvable and precipitable, and their structures and reactions were investigated by solution nuclear magnetic resonance (NMR) spectroscopy with a resolution typically attained for soluble systems. These surface-bound Pd(II) complexes were highly effective catalysts for [2+2+2] alkyne cyclotrimerization reactions to give highly congested benzene rings with fairly good selectivity. The catalytic reactivity of these interphase catalysts was even higher than that of their unbound counterparts. In addition, they can be easily separated and quantitatively recovered by simple filtration. The recovered catalysts can be effectively recycled many times and their electron microscopy images and NMR spectra showed negligible difference from those of freshly prepared. The complete transformation by Au-bound Pd(II) catalyst with a loading of 4 mol % can be achieved within 1 h for most alkynes. The same catalysis can be further accelerated in ionic liquid under microwave conditions to give nearly 100% of cyclotrimerized products in minutes.

Kinetics study and theoretical modeling of the Diels-Alder reactions of cyclopentadiene and cyclohexadiene with methyl vinyl ketone. The effects of a novel organotungsten catalyst.

The Diels-Alder reaction rate constants of methyl vinyl ketone with cyclopentadiene and cyclohexadiene in the presence of a novel organotungsten catalyst, [P(2-py)(3)W(CO)(NO)(2)](2+), have been measured experimentally and modeled theoretically at several temperatures. The uncatalyzed systems were also studied for direct comparison. When 0.0022 M of catalyst is present at room temperature, the rate constants were found to be approximately 5.3 and 5300 times higher than the corresponding uncatalyzed reactions for cyclopentadiene and cyclohexadiene systems, respectively. Experimental data suggested that the catalyst reduced the activation energies by 5-10 kcal/mol. However, the preexponential factors showed reduction of more than 3 orders of magnitude upon catalysis due to the entropic effects. The energy barriers and the rate constants of the uncatalyzed systems were accurately modeled by correlated electronic structure and dual-level variational transition state theory calculation. The calculated endo selectivity is in good agreement with the observed product distribution. Theoretical calculation also suggested the catalyzed reactions proceeded in a highly asynchronous or even stepwise fashion.