The spot sign score in primary intracerebral hemorrhage identifies patients at highest risk of in-hospital mortality and poor outcome among survivors.

BACKGROUND AND PURPOSE: The spot sign score is a potent predictor of hematoma expansion in patients with primary intracerebral hemorrhage (ICH). We aim to determine the accuracy of this scoring system for the prediction of in-hospital mortality and poor outcome among survivors in patients with primary ICH. METHODS: Three neuroradiologists retrospectively reviewed CT angiograms (CTAs) performed in 573 consecutive patients who presented to our Emergency Department with primary ICH over a 9-year period to determine the presence and scoring of spot signs according to strict criteria. Baseline ICH and intraventricular hemorrhage volumes were independently determined by computer-assisted volumetric analysis. Medical records were independently reviewed for baseline clinical characteristics and modified Rankin Scale (mRS) at hospital discharge and 3-month follow-up. Poor outcome among survivors was defined as a mRS > or =4 at 3-month follow-up. RESULTS: We identified spot signs in 133 of 573 CTAs (23.2%), 11 of which were delayed spot signs (8.3%). The presence of any spot sign increased the risk of in-hospital mortality (55.6%, OR 4.0, 95% CI 2.6 to 5.9, P<0.0001) and poor outcome among survivors at 3-month follow-up (50.8%, OR 2.5, 95% CI 1.4 to 4.3, P<0.0014). The spot sign score successfully predicted an escalating risk of both outcome measures. In multivariate analysis, the spot sign score was an independent predictor of in-hospital mortality (OR 1.5, 95% CI 1.2 to 1.9, P<0.0002) and poor outcome among survivors at 3-month follow-up (OR 1.6, 95% CI 1.1 to 2.1, P<0.0065). CONCLUSIONS: The spot sign score is an independent predictor of in-hospital mortality and poor outcome among survivors in primary ICH.

Systematic characterization of the computed tomography angiography spot sign in primary intracerebral hemorrhage identifies patients at highest risk for hematoma expansion: the spot sign score.

BACKGROUND AND PURPOSE: The presence of active contrast extravasation (the spot sign) on computed tomography (CT) angiography has been recognized as a predictor of hematoma expansion in patients with intracerebral hemorrhage. We aim to systematically characterize the spot sign to identify features that are most predictive of hematoma expansion and construct a spot sign scoring system. METHODS: We retrospectively reviewed CT angiograms performed in all patients who presented to our emergency department over a 9-year period with primary intracerebral hemorrhage and had a follow-up noncontrast head CT within 48 hours of the baseline CT angiogram. Three neuroradiologists reviewed the CT angiograms and determined the presence and characteristics of spot signs according to strict radiological criteria. Baseline and follow-up intracerebral hemorrhage volumes were determined by computer-assisted volumetric analysis. RESULTS: We identified spot signs in 71 of 367 CT angiograms (19%), 6 of which were delayed spot signs (8%). The presence of any spot sign increased the risk of significant hematoma expansion (69%, OR=92, P<0.0001). Among the spot sign characteristics examined, the presence of > or =3 spot signs, a maximum axial dimension > or =5 mm, and maximum attenuation > or =180 Hounsfield units were independent predictors of significant hematoma expansion, and these were subsequently used to construct the spot sign score. In multivariate analysis, the spot sign score was the strongest predictor of significant hematoma expansion, independent of time from ictus to CT angiogram evaluation. CONCLUSIONS: The spot sign score predicts significant hematoma expansion in primary intracerebral hemorrhage. If validated in other data sets, it could be used to select patients for early hemostatic therapy.

Pulsed-high intensity focused ultrasound enhanced tPA mediated thrombolysis in a novel in vivo clot model, a pilot study.

INTRODUCTION: Thrombotic disease continues to account for significant morbidity and mortality. Ultrasound energy has been investigated as a potential primary and adjunctive treatment for thrombotic disease. We have previously shown that pulsed-high intensity focused ultrasound (HIFU) enhances thrombolysis induced by tissue plasminogen activator (tPA) in vitro, including describing the non-destructive mechanism by which tPA availability and consequent activity are increased. In this study we aimed to determine if the same effects could be achieved in vivo. MATERIALS AND METHODS: In this study, pulsed-HIFU exposures combined with tPA boluses were compared to treatment with tPA alone, HIFU alone and control in a novel in vivo clot model. Clots were formed in the rabbit marginal ear vein and verified using venography and infrared imaging. The efficacy of thrombolytic treatment was monitored via high resolution ultrasonography for 5 h post-treatment. The cross-sectional area of clots at 4 points along the vein was measured and normalized to the pre-treatment size. RESULTS: At 5 h the complete recanalization of clots treated with pulsed-HIFU and tPA was significantly different from the partial recanalization seen with tPA treatment alone. tPA treatment alone showed a significant decrease in clot versus control, where HIFU was not significantly different than control. Histological analysis of the vessel walls in the treated veins showed no apparent irreversible damage to endothelial cells or extravascular tissue. CONCLUSIONS: This study demonstrates that tPA mediated thrombolysis can be significantly enhanced when combined with non-invasive pulsed-HIFU exposures.

Radiofrequency ablation of renal tumors.

Radiofrequency ablation (RFA) of renal tumors is a promising technique that plays a unique and increasingly important role in urologic oncology practices. RFA is appealing as a minimally invasive therapy that may be performed on an outpatient basis. It enables treatment of an area 3 to 5 cm in diameter, with relatively low morbidity and mortality rates. Most interventional radiologists (IRs) are familiar with RFA of liver tumors, and several principles and techniques used in the liver may be extrapolated for use in the kidney. However, it is crucial to bear in mind that local tumor ablation in the kidney presents unique challenges, secondary to the kidney's unique anatomic and physiologic features. Clinical and technical considerations, risks, and complications pertaining to RFA of renal tumors are reviewed here, including approaches commonly used in our practice.

CT angiography spot sign predicts in-hospital mortality in patients with secondary intracerebral hemorrhage.

BACKGROUND AND OBJECTIVE: The presence of active contrast extravasation during CT angiography, the spot sign, is a potent predictor of in-hospital mortality in patients with primary intracerebral hemorrhage (ICH). However, its predictive value in patients with ICH due to a vascular abnormality, secondary ICH (SICH), is unknown. The aim of this study was to determine the clinical and radiological predictors of a spot sign and in-hospital mortality in patients with SICH. METHODS: Two experienced readers independently reviewed CT angiograms performed on 215 consecutive patients presenting to the emergency department with SICH over a 10-year period to assess the presence of spot signs according to strict radiological criteria. Differences in reader interpretation were resolved by consensus. Medical records were reviewed for baseline clinical characteristics and in-hospital mortality. Univariate and multivariate logistic regression analyses were performed to determine the clinical and radiological predictors of a spot sign and in-hospital mortality in patients with SICH. RESULTS: Spot signs were identified in 31 of 215 patients with SICH (14.4%), four of which were delayed spot signs (12.9%). Spot signs were most common in patients with arteriovenous fistulas (42%), Moyamoya (40%), elevated admission blood glucose (23%) and large intraventricular hemorrhage volumes (29%). Spot signs were most predictive of in-hospital mortality in patients with aneurysms of the anterior cerebral artery (100%) and anterior communicating artery (75%). In univariate analysis, the presence of a spot sign significantly increased the risk of in-hospital mortality in patients with SICH (38.7%, OR 2.2, 95% CI 1.0 to 4.9, p=0.0497). However, in multivariate logistic regression analysis the admission Glasgow Coma Scale was the only independent predictor of in-hospital mortality in patients with SICH (OR 2.8, 95% CI 1.6 to 5.1, p=0.0004). CONCLUSION: The spot sign identifies patients with SICH at increased risk of in-hospital mortality. However, the admission Glasgow Coma Scale was the only independent predictor of in-hospital mortality in this cohort of patients with SICH.

In vitro investigations into enhancement of tPA bioavailability in whole blood clots using pulsed-high intensity focused ultrasound exposures.

Investigations were carried out on the manner by which pulsed-high intensity focused ultrasound (HIFU) enhances the effectiveness of tissue plasminogen activator (tPA) in whole blood clots, in vitro. Scanning electronic microscope (SEM) of the surface of the clots showed that the exposures increased exposed fibrin, as well as the number of openings to more interior regions. These findings were supported by fluorescent antibody labeling of tPA in frozen sections of clots treated post-HIFU. Here, improved accumulation at the surface and penetration of the tPA into the clots were observed in those treated with HIFU. Fluorescence recovery after photobleaching was also performed, indicating that the diffusion coefficient increased 6.3-fold for fluorescently labeled dextrans, comparable in size to tPA, in the HIFU-treated clots. Improved understanding of the manner by which pulsed--HIFU exposures can improve the effectiveness of thrombolytics will help optimize the exposures for this application and potentially facilitate translation to the clinic.

Emerging local ablation techniques.

Local ablation technologies for hepatic malignancy have developed rapidly in the past decade, with advances in several percutaneous or externally delivered treatment methods including radiofrequency ablation, microwave ablation, laser ablation, and high-intensity focused ultrasound. Research has focused on increasing the size of the ablation zone and minimizing heat-sink effects. More recent developments include improvements in treatment planning and navigation with integration of several imaging modalities, as well as automated delivery of the ablation through robotics. These improvements will allow increased consistency in treatment delivery and will facilitate translation to the community setting. Combination therapies with multimodality guidance are on the cutting edge of image-guided, minimally invasive cancer therapies. Local ablation is being combined with regional therapies, such as arterial chemoembolization and local activation of systemically administered drugs, with promising results. Potential combinations with local ablation also include external radiation therapy and antitumor immune modulation. Image-guided oncology is emerging as an important part of the interventional radiology practice, thanks in part to the innovation and imaging background that lies at the roots of our discipline.

Pulsed high-intensity focused ultrasound enhances thrombolysis in an in vitro model.

PURPOSE: To evaluate the use of pulsed high-intensity focused ultrasound exposures to improve tissue plasminogen activator (tPA)-mediated thrombolysis in an in vitro model. MATERIALS AND METHODS: All experimental work was compliant with institutional guidelines and HIPAA. Clots were formed by placing 1 mL of human blood in closed-off sections of pediatric Penrose tubes. Four experimental groups were evaluated: control (nontreated) clots, clots treated with pulsed high-intensity focused ultrasound only, clots treated with tPA only, and clots treated with pulsed high-intensity focused ultrasound plus tPA. The focused ultrasound exposures (real or sham) were followed by incubations of the clots in tPA with saline or in saline only. Thrombolysis was measured as the relative reduction in the mass of the clot. D-Dimer assays also were performed. Two additional experiments were performed and yielded dose-response curves for two exposure parameters: number of pulses per raster point and total acoustic power. Radiation force-induced displacements caused by focused ultrasound exposures were simulated in the clots. A Tukey-Kramer honestly significant difference test was performed for comparisons between all pairs of experimental groups. RESULTS: The clots treated with focused ultrasound alone did not show significant increases in thrombolysis compared with the control clots. The clots treated with focused ultrasound plus tPA showed a 50% ([30.2/20.1]/20.1) increase in the degree of thrombolysis compared with the clots treated with tPA only (P < .001), further corroborating the d-dimer assay results (P < .001). Additional experiments revealed how increasing both the number of pulses per raster point and the total acoustic power yielded corresponding increases in the thrombolysis rate. In the latter experiment, simulations performed at a range of power settings revealed a direct correlation between increased displacement and observed thrombolysis rate. CONCLUSION: The rate of tPA-mediated thrombolysis can be enhanced by using pulsed high-intensity focused ultrasound exposure in vitro.