Justin P. McWilliams

Dual-energy CT for the assessment of contrast material distribution in the pulmonary parenchyma.

OBJECTIVE The purpose of this study was to assess the feasibility and diagnostic value of dual-energy CT iodine mapping at pulmonary CT angiography. SUBJECTS AND METHODS Ninety-three patients underwent CT angiography with the dual-energy technique on a dual-source CT scanner. Postprocessing was used to map iodine in the lung parenchyma on the basis of its spectral behavior, and image quality was assessed by two readers. Iodine distribution patterns were rated as homogeneous, patchy, or circumscribed defects. Conventional CT angiographic images reconstructed from the same data sets were reviewed for the presence and localization of pulmonary embolism, whether embolic occlusion was partial or complete, and the presence of changes in the lung parenchyma. Dual-energy perfusion findings were correlated with the CT angiographic and lung-window CT findings in per-patient and per-segment analyses. RESULTS Iodine distribution was homogeneous in 49 patients, of whom CT angiography showed no pulmonary embolism in 46 patients and nonocclusive pulmonary emboli in three patients. Images of 29 patients showed a patchy pattern; 24 of these patients had no pulmonary embolism, and five had nonocclusive pulmonary emboli with solely nonocclusive intravascular clots. Images of 15 patients showed segmental or subsegmental defects; four of these patients had evidence of pulmonary embolism, and 11 had occlusive pulmonary emboli with at least one occlusive clot in the pulmonary vasculature. CONCLUSION Dual-energy CT is reliable in the detection of defects in pulmonary parenchymal iodine distribution that correspond to embolic vessel occlusion.

A Biomechanical Comparison of Tibial Inlay and Tibial Tunnel Posterior Cruciate Ligament Reconstruction Techniques Graft Pretension and Knee Laxity

Background Most posterior cruciate ligament reconstruction techniques use a tibial bone tunnel, which results in an acute bend in the graft as it passes over the posterior portion of the tibial plateau. Hypothesis The tibial inlay technique will result in lower graft pretensions, less laxity, and less stretch-out after cyclic loading. Study Design Controlled laboratory study. Methods Graft pretensions necessary to restore normal laxity at 90° of knee flexion (laxity match pretension) and anteroposterior laxities at five knee flexion angles were recorded in 12 fresh-frozen knee specimens with bone-patellar tendon-bone posterior cruciate ligament graft reconstructions using both techniques and two femoral tunnel positions. Results When the graft was placed in a central femoral tunnel, the tibial tunnel reconstruction required an average 15.6 N greater laxity match pretension than the tibial inlay reconstruction. There were no significant differences in mean knee laxities between the tibial tunnel and tibial inlay techniques at any knee flexion angle; both reconstruction techniques restored mean knee laxity to within 1.6 mm of intact knee values over the entire flexion range. Conclusions There was no important advantage of one technique over the other with respect to the biomechanical parameters measured.

Biomechanical comparison of tibial inlay and tibial tunnel techniques for reconstruction of the posterior cruciate ligament. Analysis of graft forces.

Background: The tibial inlay technique of reconstruction of the posterior cruciate ligament offers potential advantages over the conventional transtibial tunnel technique, particularly with regard to the graft force levels that develop over a functional range of knee flexion. Abnormally high graft forces generated during rehabilitation activities could lead to stretch-out of the graft during the critical early healing period. The purpose of this study was to compare graft forces between these two techniques and with forces in the native posterior cruciate ligament. Methods: A load cell was installed at the femoral origin of the posterior cruciate ligament in twelve fresh-frozen cadaveric knees to measure resultant forces in the ligament during a series of knee loading tests. The posterior cruciate ligament was then excised, and the femoral ends of 10-mm-wide bone-patellar tendon-bone grafts were attached to the load cell to measure resultant forces in the grafts. For the tunnel reconstruction, the distal bone block of the graft was placed into a tibial tunnel and thin stainless-steel cables interwoven into the bone block were gripped in a split clamp attached to the anterior tibial cortex. With the inlay technique, the distal bone block was fixed in a tibial trough with use of a cortical bone screw with a washer and nut. The proximal ends of all grafts were pretensioned to a level of force that restored intact knee laxity at 90° of flexion, and loading tests were repeated. Results: There were no significant differences in mean graft forces between the two techniques under tibial loads consisting of 100 N of posterior tibial force, 5 N-m of varus and valgus moment, and 5 N-m of internal and external tibial torque. Mean graft forces with the tibial tunnel technique were approximately 10 to 20 N higher than those with the inlay technique with passive knee flexion beyond 95°. Mean graft forces with both reconstruction techniques were significantly higher than forces in the native posterior cruciate ligament with the knee flexed beyond approximately 90° for all but one mode of loading. Conclusions: In this cadaveric testing model, neither technique for reconstruction of the posterior cruciate ligament had a substantial advantage over the other with respect to generation of graft forces. Clinical Relevance: The relatively high graft forces (compared with the forces in the native posterior cruciate ligament) observed beyond 90° of knee flexion after reconstruction of the posterior cruciate ligament with either the tunnel or the inlay technique suggest that rehabilitation activities that involve loading of the knee while it is flexed beyond 90° (such as kneeling, squatting, or climbing high stairs) should be avoided in the early postoperative period.

Percutaneous Ablation of Hepatocellular Carcinoma: Current Status

Hepatocellular carcinoma (HCC) is an increasingly common disease with dismal long-term survival. Percutaneous ablation has gained popularity as a minimally invasive, potentially curative therapy for HCC in nonoperative candidates. The seminal technique of percutaneous ethanol injection has been largely supplanted by newer modalities, including radiofrequency ablation, microwave ablation, cryoablation, and high-intensity focused ultrasound ablation. A review of these modalities, including technical success, survival rates, and complications, will be presented, as well as considerations for treatment planning and follow-up.

Inferior Vena Cava Filter Retrieval: Effectiveness and Complications of Routine and Advanced Techniques

PURPOSE To investigate the success and safety of routine versus advanced inferior vena cava (IVC) filter retrieval techniques. MATERIALS AND METHODS A retrospective review was performed of patients who underwent IVC filter placement and/or a retrieval attempt over a 10-year period. Retrieval technique(s), preretrieval computed tomography, preretrieval venography, and clinical/imaging follow-up for 30 days after retrieval were analyzed. Mean filter dwell time was 134 days (range, 0-2,475 d). RESULTS Filter retrieval was attempted 231 times in 217 patients (39% female, 61% male; mean age, 50.7 y), with success rates of 73.2% (169 of 231) and 94.7% (54 of 57) for routine and advanced filter retrieval techniques, respectively. The overall filter retrieval complication rate was 1.7% (four of 231); complications in four patients (with multiple complications in some cases) included IVC dissection, IVC intussusception, IVC thrombus/stenosis, filter fracture with embedded strut, IVC injury with hemorrhage, and vascular injury from complicated venous access. The rate of complications associated with filter retrievals that required advanced technique was significantly higher than seen with routine technique (5.3% vs 0.4%; P < .05). Longer dwell time, more transverse tilt, and presence of an embedded hook were associated with significantly increased rates of failed retrieval via routine technique (P < .05). CONCLUSIONS IVC filters can be retrieved with a high overall success rate (98.2%) and a low complication rate (1.7%) by using advanced techniques when the routine approach has failed; however, the use of advanced techniques is associated with a significantly higher complication rate.

Society of Interventional Radiology position statement: prostate artery embolization for treatment of benign disease of the prostate.

Prostatic artery embolization (PAE) is a promising new treatment for lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH). It has therefore garnered much interest in the interventional community. This article will review the scientific background for this therapy, describe the current devices available for treatment, and state the position of the Society of Interventional Radiology (SIR) with regard to the study and potential adoption of this therapy.

Coil-Assisted Retrograde Transvenous Obliteration (CARTO) for the Treatment of Portal Hypertensive Variceal Bleeding: Preliminary Results

OBJECTIVES:To describe the technical feasibility, safety, and clinical outcomes of coil-assisted retrograde transvenous obliteration (CARTO) in treating portal hypertensive non-esophageal variceal hemorrhage.METHODS:From October 2012 to December 2013, 20 patients who received CARTO for the treatment of portal hypertensive non-esophageal variceal bleeding were retrospectively evaluated. All 20 patients had at least 6-month follow-up. All patients had detachable coils placed to occlude the efferent shunt and retrograde gelfoam embolization to achieve complete thrombosis/obliteration of varices. Technical success, clinical success, rebleeding, and complications were evaluated at follow-up.RESULTS:A 100% technical success rate (defined as achieving complete occlusion of efferent shunt with complete thrombosis/obliteration of bleeding varices and/or stopping variceal bleeding) was demonstrated in all 20 patients. Clinical success rate (defined as no variceal rebleeding) was 100%. Follow-up computed tomography after CARTO demonstrated decrease in size with complete thrombosis and disappearance of the varices in all 20 patients. Thirteen out of the 20 had endoscopic confirmation of resolution of varices. Minor post-CARTO complications, including worsening of esophageal varices (not bleeding) and worsening of ascites/hydrothorax, were noted in 5 patients (25%). One patient passed away at 24 days after the CARTO due to systemic and portal venous thrombosis and multi-organ failure. Otherwise, no major complication was noted. No variceal rebleeding was noted in all 20 patients during mean follow-up of 384±154 days.CONCLUSIONS:CARTO appears to be a technically feasible and safe alternative to traditional balloon-occluded retrograde transvenous obliteration or transjugular intrahepatic portosystemic shunt, with excellent clinical outcomes in treating portal hypertensive non-esophageal variceal bleeding.

Biomechanical effects of medial–lateral tibial tunnel placement in posterior cruciate ligament reconstruction

With most posterior cruciate (PCL) reconstruction techniques, the distal end of the graft is fixed within a tibial bone tunnel. Although a surgical goal is to locate this tunnel at the center of the PCLs tibial footprint, errors in medial–lateral tunnel placement of the tibial drill guide are possible because the position of the tip of the guide relative to the PCLs tibial footprint can be difficult to visualize from the standard arthroscopy portals. This study was designed to measure changes in knee laxity and graft forces resulting from mal‐position of the tibial tunnel medial and lateral to the center of the PCLs tibial insertion. Bone–patellar tendon–bone allografts were inserted into three separate tibial tunnels drilled into each of 10 fresh‐frozen knee specimens. Drilling the tibial tunnel 5 mm medial or lateral to the center of the PCLs tibial footprint had no significant effect on knee laxities: the graft pretension necessary to restore normal laxity at 90° of knee flexion (laxity match pretension) with the medial tunnel was 13.8 N (29%) greater than with the central tunnel. During passive knee flexion–extension, graft forces with the medial tibial tunnel were significantly higher than those with the central tunnel for flexion angles greater than 65° while graft forces with the central tibial tunnel were not significantly different than those with the lateral tibial tunnel. Graft forces with medial and lateral tunnels were not significantly different from those with a central tunnel for 100 N applied posterior tibial force, 5 N m applied varus and valgus moment, and 5 N m applied internal and external tibial torque. With the exception of slightly higher graft forces recorded with the medial tunnel beyond 65° of passive knee flexion, errors in medial–lateral placement of the tibial tunnel would not appear to have important effects on the biomechanical characteristics of the reconstructed knee.

Knee Function after Anterior Cruciate Ligament Injury in Elite Collegiate Athletes

Background Anterior cruciate ligament injuries are common in athletes, but there are few studies of long-term outcomes. Hypothesis Long-term knee function of anterior cruciate ligament-injured athletes is inferior to that of their uninjured teammates. Study Design Retrospective cohort study. Methods Thirty-three Division I-A athletes who had sustained an anterior cruciate ligament injury during their college career completed a series of questionnaires that assessed knee function and quality of life 2 to 14 years after injury. Their responses were compared with those of a matched cohort of their uninjured teammates. Results There were no differences in the mean Tegner scores, modified Lysholm scores, or in the scores of the SF-36 between groups. Sixteen anterior cruciate ligament-injured athletes scored A or B in the subjective portion of the International Knee Documentation Committee score and 17 scored C or D, whereas 24 control subjects scored A or B and 9 scored C or D, a statistically significant difference between groups. Five injured and 14 control athletes had participated at a professional or national team level after college. Conclusions Quality of life of elite collegiate athletes who sustained an anterior cruciate ligament injury was not significantly different from that of their uninjured teammates, but knee function differed between groups.

Effect of Topical Intranasal Therapy on Epistaxis Frequency in Patients With Hereditary Hemorrhagic Telangiectasia: A Randomized Clinical Trial

IMPORTANCE Epistaxis is a major factor negatively affecting quality of life in patients with hereditary hemorrhagic telangiectasia (HHT; also known as Osler-Weber-Rendu disease). Optimal treatment for HHT-related epistaxis is uncertain. OBJECTIVE To determine whether topical therapy with any of 3 drugs with differing mechanisms of action is effective in reducing HHT-related epistaxis. DESIGN, SETTING, AND PARTICIPANTS The North American Study of Epistaxis in HHT was a double-blind, placebo-controlled randomized clinical trial performed at 6 HHT centers of excellence. From August 2011 through March 2014, there were 121 adult patients who met the clinical criteria for HHT and had experienced HHT-related epistaxis with an Epistaxis Severity Score of at least 3.0. Follow-up was completed in September 2014. INTERVENTIONS Patients received twice-daily nose sprays for 12 weeks with either bevacizumab 1% (4 mg/d), estriol 0.1% (0.4 mg/d), tranexamic acid 10% (40 mg/d), or placebo (0.9% saline). MAIN OUTCOMES AND MEASURES The primary outcome was median weekly epistaxis frequency during weeks 5 through 12. Secondary outcomes included median duration of epistaxis during weeks 5 through 12, Epistaxis Severity Score, level of hemoglobin, level of ferritin, need for transfusion, emergency department visits, and treatment failure. RESULTS Among the 121 patients who were randomized (mean age, 52.8 years [SD, 12.9 years]; 44% women with a median of 7.0 weekly episodes of epistaxis [interquartile range {IQR}, 3.0-14.0]), 106 patients completed the study duration for the primary outcome measure (43 were women [41%]). Drug therapy did not significantly reduce epistaxis frequency (P = .97). After 12 weeks of treatment, the median weekly number of bleeding episodes was 7.0 (IQR, 4.5-10.5) for patients in the bevacizumab group, 8.0 (IQR, 4.0-12.0) for the estriol group, 7.5 (IQR, 3.0-11.0) for the tranexamic acid group, and 8.0 (IQR, 3.0-14.0) for the placebo group. No drug treatment was significantly different from placebo for epistaxis duration. All groups had a significant improvement in Epistaxis Severity Score at weeks 12 and 24. There were no significant differences between groups for hemoglobin level, ferritin level, treatment failure, need for transfusion, or emergency department visits. CONCLUSIONS AND RELEVANCE Among patients with HHT, there were no significant between-group differences in the use of topical intranasal treatment with bevacizumab vs estriol vs tranexamic acid vs placebo and epistaxis frequency. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01408030.