Dean Nakamoto

Increased carotid intima media thickness and cardiac biomarkers in Hiv infected children

Objectives:To assess carotid intima media thickness (IMT) and cardiac biomarkers in HIV infected children on antiretroviral therapy (ART). Methods:This was a single site, cross sectional, controlled observational study. We assessed carotid IMT, homocysteine, high-sensitivity C-reactive protein and myeloperoxidase levels in HIV infected children on stable ART for ≥ 6 months. Carotid IMT was reported as internal carotid artery (ICA) and common carotid artery (CCA) thickness; left and right sides were measured separately. Groups were compared using appropriate two-sample tests. Results:Of the 62 subjects enrolled, 31 were HIV positive (50%), 66% were female, and 69% were African–American. Median CD4% was 32% and 26 patients (84%) had HIV-1 RNA< 400 copies/ml. Sixteen patients had been taking protease inhibitors for a median duration of 27 months. None had hypertension or smoked. HIV infected children had higher HOMA-IR, waist-to-hip ratio, cholesterol, triglycerides, myeloperoxidase and lower homocysteine levels. Left and right CCA IMT, and left and right ICA IMT were significantly higher in the HIV infected group. Significant predictors of carotid IMT measurements in uninfected controls were body mass index and homocysteine, but only the duration of ARV therapy was predictive of IMT in the HIV infected group. Conclusion:Higher levels of carotid IMT and some cardiac markers were found in ART treated HIV infected children when compared to matched uninfected controls. These results suggest that HIV infected children receiving ART may be at increased risk of cardiovascular disease.

Percutaneous Cryoablation of Renal Masses: Impact of Patient Selection and Treatment Parameters on Outcomes

OBJECTIVES To evaluate whether the trend in patient selection or perioperative parameters were associated with treatment outcomes after percutaneous cryoablation (PCA) of renal masses. METHODS We retrospectively analyzed our urological oncology database and identified 52 patients treated for a total of 54 renal masses. Univariate analysis was performed to evaluate whether the variables of age, gender, tumor size, number of probes used, total freezing time, preoperative creatinine, American Society of Anesthesia class, body mass index, or age-adjusted Charlson comorbidity index (CCI) score had an impact on the outcomes of treatment failure or the complication rate. RESULTS During a mean follow-up of 21 months, recurrence-free, overall, and disease-specific (based on radiographic follow-up and biopsy) survival were 96.2%, 98.1% and 100%, respectively. The mean age-adjusted CCI score for patients with postoperative complications was 6.5, compared with a mean score of 3.0 in patients without postoperative complications (P = .02). The complication rate was also significantly higher when a greater number of cryoprobes were used during PCA (P < .005). None of the variables analyzed were predictive of treatment failure. CONCLUSIONS Of the pre- and intraoperative variables studied, age-adjusted CCI score and number of cryoprobes used were the only variables with predictive value for outcomes in regard to treatment failure or complications. As investigators continue using cryoablation to treat renal masses, it is important to be able to completely and honestly counsel patients regarding the likelihood of complications and need for subsequent therapy in the setting of treatment failure.

Clinical evaluation of CAIPIRINHA: Comparison against a GRAPPA standard

To evaluate image quality when using a CAIPIRINHA sampling pattern in comparison to a standard GRAPPA sampling pattern in patients undergoing a routine three‐dimensional (3D) breathheld liver exam. CAIPIRINHA uses an optimized phase encoding sampling strategy to alter aliasing artifacts in 3D acquisitions to improve parallel imaging reconstruction.

Simultaneous magnetic resonance angiography and perfusion (MRAP) measurement: initial application in lower extremity skeletal muscle.

To obtain a simultaneous 3D magnetic resonance angiography and perfusion (MRAP) using a single acquisition and to demonstrate MRAP in the lower extremities. A time‐resolved contrast‐enhanced exam was used in MRAP to simultaneously acquire a contrast‐enhanced MR angiography (MRA) and dynamic contrast‐enhanced (DCE) perfusion, which currently requires separate acquisitions and thus two contrast doses. MRAP can be used to assess large and small vessels in vascular pathologies such as peripheral arterial disease.

Free-breathing liver perfusion imaging using 3-dimensional through-time spiral generalized autocalibrating partially parallel acquisition acceleration.

Objectives The goal of this study was to develop free-breathing high–spatiotemporal resolution dynamic contrast-enhanced liver magnetic resonance imaging using non-Cartesian parallel imaging acceleration, and quantitative liver perfusion mapping. Materials and Methods This study was approved by the local institutional review board and written informed consent was obtained from all participants. Ten healthy subjects and 5 patients were scanned on a Siemens 3-T Skyra scanner. A stack-of-spirals trajectory was undersampled in-plane with a reduction factor of 6 and reconstructed using 3-dimensional (3D) through-time non-Cartesian generalized autocalibrating partially parallel acquisition. High-resolution 3D images were acquired with a true temporal resolution of 1.6 to 1.9 seconds while the subjects were breathing freely. A dual-input single-compartment model was used to retrieve liver perfusion parameters from dynamic contrast-enhanced magnetic resonance imaging data, which were coregistered using an algorithm designed to reduce the effects of dynamic contrast changes on registration. Image quality evaluation was performed on spiral images and conventional images from 5 healthy subjects. Results Images with a spatial resolution of 1.9 × 1.9 × 3 mm3 were obtained with whole-liver coverage. With an imaging speed of better than 2 s/vol, free-breathing scans were achieved and dynamic changes in enhancement were captured. The overall image quality of free-breathing spiral images was slightly lower than that of conventional long breath-hold Cartesian images, but it provided clinically acceptable or better image quality. The free-breathing 3D images were registered with almost no residual motion in liver tissue. After the registration, quantitative whole-liver 3D perfusion maps were obtained and the perfusion parameters are all in good agreement with the literature. Conclusions This high–spatiotemporal resolution free-breathing 3D liver imaging technique allows voxelwise quantification of liver perfusion.

Use of Fibrinolytic Agents to Coat Wire Implants to Decrease Infection: An Animal Model

RATIONALE AND OBJECTIVES. Infection is a serious complication of metallic prosthesis implantation and may necessitate removal of the prosthesis. This study uses an animal model to evaluate the effects of coating stainless steel wire implants with fibrinolytic agents to prevent infection after bacterial contamination. METHODS. Three types of steel wire implants were used: plain stainless steel, heparin-coated steel, and urokinase-heparin- coated steel. Wire implants were incubated in a known concentration of Staphylococcus epidermidis and placed into the subcutaneous tissues of three groups of anesthetized hamsters. The implants and surrounding tissues were excised after 1 week and submitted for quantitative cultures. RESULTS. Using 100 organisms as the upper allowable limit to categorize abscesses as noninfected, the following rates of noninfectivity were observed: group 1 (control), 0% noninfected; group 2 (heparin-coated wire), 40% noninfected; and group 3 (urokinasc-heparin-coated wire), 50% noninfected. The noninfectivity rates of groups 2 and 3 were significantly higher than the rate of group 1 (P < 0.001). There was no significant difference between groups 2 and 3 (P=0.19). CONCLUSIONS.Both the heparin-coated and urokinase-heparin-coated wire exhibited significantly decreased infection rates compared with uncoated wire; the heparin coating may inhibit bacterial adherence. The urokinase coating of the heparin-coated to further decrease the infection rate, but not to a statistically significant degree.

Image‐guided biopsy of small renal masses in the era of ablative therapies

To further evaluate the accuracy, safety, and impact of image‐guided renal biopsies on clinical decision making and management of the indeterminate small renal masses.

Young Investigator Award. In vivo treatment of infected prosthetic graft material with urokinase: an animal model.

PURPOSE Pyogenic infection of vascular grafts represents a serious complication that may necessitate graft removal. If better treatment methods could be developed, perhaps some infected grafts could be salvaged and not removed. This study reports an animal model that evaluates the sterilization of contaminated vascular graft material implants with urokinase and antibiotics. MATERIALS AND METHODS Polytetrafluoroethylene (PTFE) implants were incubated overnight in a known concentration of bacteria (Staphylococcus epidermidis) and were then implanted subcutaneously into four groups of anesthetized hamsters. The first group (control) received no treatment. The second group received urokinase injections twice daily into each abscess. The third group received intraabscess urokinase and systemic gentamicin twice daily. The fourth group received only systemic gentamicin. The hamsters were killed after 1 week. The graft implants and surrounding tissues were excised and submitted for quantitative cultures. RESULTS With use of a cutoff value of 100 organisms per milliliter, below which the abscesses were considered noninfected, the following rates of noninfectivity were observed: group 1 (control), 5% noninfected; group 2 (urokinase only), 19.4%; group 3 (urokinase and gentamicin), 63.2%; and group 4 (gentamicin only), 32.5%. The noninfectivity rate of group 3 was significantly higher than that of all other groups combined (P < .001) and was significantly better than that of group 4 alone (P = .013). CONCLUSION The combination of intraabscess urokinase and systemic gentamicin is very synergistic in graft sterilization. Urokinase may assist in the degradation of both fibrin and the biofilm produced by S epidermidis, thus improving penetration of antibiotics and local host defense mechanisms.

Inflammatory Pseudotumor of the Spleen: Review of clinical presentation and diagnostic methods

We describe a 91-year-old woman with a clinical history of invasive ductal carcinoma of the breast diagnosed in 1991 who was admitted because of dizziness, poor appetite, and some swelling and tenderness over her cheeks. The patients initial work up revealed a 5-cm well-demarcated hypodense solid lesion in her spleen with abnormally intense uptake on PET/CT scan raising suspicion for malignancy i.e. breast metastasis versus lymphoma. Further review demonstrated the presence of this splenic lesion, though slightly smaller, on a CT scan from ten years earlier (2000). An ultrasonographic guided core needle splenic biopsy was performed and the pathology result revealed histological findings compatible with inflammatory pseudotumor of the spleen. As a result, unnecessary splenectomy was avoided.

Percutaneous computed tomography guided cryoablation of the celiac plexus as an alternative treatment for intractable pain caused by pancreatic cancer

Computed Tomography (CT)-guided percutaneous cryoablation was performed in a 43-year-old patient with intractable epigastric abdominal pain caused by advanced adenocarcinoma of the pancreas and extensive celiac trunk involvement. Initial treatment with celiac plexus nerve neurolysis using local ethanol injection was unsuccessful. A 17-gauge 17-cm cryoablation probe (Galil Medical Inc. Plymouth Meeting, PA) was placed into the expected location of the celiac plexus through a left paraspinal approach under CT guidance and two cycles of freeze-thaw were performed. Patients pain decreased from 10 of 10 (subjective pain scoring using a visual analog scale; VAS; 0-10) to 3. No post-procedure complication was observed. His pain has remained stable after 6 months of follow up. Percutaneous cryoablation appears to be an effective alternative to neurolytic celiac plexus block for palliative treatment of celiac plexus involvement. Further study with larger number of patients is needed to evaluate the safety and efficacy.