A novel technique for preoperative localization of pulmonary nodules using a mixture of tissue adhesive and iohexol under computed tomography guidance: A 140 patient single-center study.

BACKGROUND: The increase in the incidence of pulmonary nodules has made computed tomography (CT) screening a requirement for diagnosis and treatment. Small pulmonary nodule detection during video-assisted thoracoscopic surgery (VATS) or thoracotomy is frequently challenging; however, accurate and efficient localization of nodules is critical for precise resection. Herein, we introduce and evaluate the feasibility and safety of a novel technique for preoperative pulmonary nodule localization. METHODS: From March 2018 to December 2019, 140 patients with 153 pulmonary nodules measuring <2 cm in diameter were enrolled in this study. Preoperative, CT-guided localization was performed on each nodule with an injected mixture of tissue adhesive and iohexol. Patient and nodule characteristics, localization data, complications, surgical data, and pathological results were analyzed. RESULTS: All 153 nodules in 140 patients were successfully marked preoperatively and detected during surgery (n = 153/153). Mean nodule size was 8.7 ± 2.6 mm, and mean distance from nodule to pleura was 7.9 ± 8.2 mm. The mean procedural time was 8.7 ± 1.0 min. Nine patients (6.4%) underwent two simultaneous nodule localizations and two patients (1.4%) underwent three simultaneous nodule localizations. Pneumothorax (17/140, 12.1%), pain (6/140, 4.3%), and pungent odor (5/140, 3.6%) were the major complications. No patient required further treatment, and no allergic reactions or embolisms were observed. CONCLUSIONS: Preoperative CT-guided nodule localization using a mixture of tissue adhesive and iohexol is an efficient technique for localizing small and impalpable pulmonary lesions, including multiple pulmonary nodules. Our study demonstrates that this novel method is safe and straightforward to implement.

A randomized comparison of a novel iopromide-based paclitaxel-coated balloon Shenqi versus SeQuent Please for the treatment of in-stent restenosis.

BACKGROUND: Treatment of coronary in-stent restenosis (ISR) remains challenging in contemporary clinical applications. Drug-coated balloon (DCB) angioplasty offers an effective treatment for ISR. Shenqi is a novel iopromide-based paclitaxel-coated balloon and its clinical safety, effectiveness and angiographic efficacy in patients with ISR have not been investigated. METHODS: A total of 216 subjects with the first occurrence of ISR at 11 investigational sites in China were randomly allocated in a 1:1 fashion to treatment with DCB SeQuent Please or Shenqi. Clinical follow-up was planned at 1, 6, 9 and 12 months, and angiographic follow-up was planned at 9 months. The study was powered for the primary endpoint of 9-month in-segment late loss. RESULTS: At 9-month follow-up, the in-segment late loss was 0.29 ± 0.43 mm with Shenqi versus 0.30 ± 0.46 mm with SeQuent Please, and the one-sided 97.5% upper confidence limit of the difference was 0.14 mm, achieving noninferiority of Shenqi compared with SeQuent Please (P = 0.002). In total, 12 patients developed target lesion failure (TLF) in the Shenqi group compared with 16 patients in the SeQuent Please group (10.91% versus 15.09%; P = 0.42) within 1 year. TLF was mainly driven by target lesion revascularization (9.09%) followed by target vessel-related myocardial infarction (1.82%) and cardiovascular death (0.91%) in the Shenqi group. CONCLUSIONS: Shenqi DCB was noninferior to SeQuent Please DCB for the primary endpoint of 9-month in-segment late loss. Shenqi DCB may become an attractive alternative treatment for patients with coronary ISR, withholding the need for additional stent implantation.

Computed tomographic lymphangiography of the thoracic duct by subcutaneous iohexol injection into the metatarsal region.

OBJECTIVE: To evaluate the efficacy of subcutaneous iohexol injection into the metatarsal region for thoracic duct lymphangiography in dogs and to determine the minimum effective dose. STUDY DESIGN: Experimental study and clinical report. ANIMALS: Five healthy beagle dogs and one dog with chylothorax. METHODS: For the experimental study, iohexol was injected subcutaneously into the metatarsal region of five dogs at three doses (0.5, 0.75, and 1 mL/kg), and the injection sites were massaged gently. Computed tomography (CT) was performed 1, 3, 5, 7, 10, 15, and 20 minutes after iohexol injection. Subjective quality was assessed, and Hounsfield unit values were measured at several regions of interest (T1, T4, T8, T13, and L3). In the dog with chylothorax, iohexol (1.0 mL/kg) was injected into the right metatarsal region prior to CT. RESULTS: The thoracic duct was visualized and enhanced by contrast in all dogs after injection of 0.75 and 1.0 mL/kg of iohexol, and in two dogs after injection of 0.5 mL/kg at 3, 5, and 7 minutes. The thoracic duct was gradually attenuated with increasing doses of iohexol. In the dog with chylothorax, the entire thoracic duct was well enhanced and dilated, and tortuous cranial mediastinal lymphatics were detected. CONCLUSION: The thoracic duct was visualized when at least 0.75 mL/kg of iohexol was injected subcutaneously into the metatarsal region of dogs. CLINICAL SIGNIFICANCE: Subcutaneous injection of iohexol into the metatarsal region offers a simple alternative to conventional thoracic duct lymphangiography.

Outcomes of a low-osmolar water-soluble contrast pathway in small bowel obstruction.

BACKGROUND: Adhesive small-bowel obstruction (SBO) is a common surgical condition accounting for a significant proportion of acute surgical admissions and surgeries. The implementation of a high-osmolar water-soluble contrast challenge has repeatedly been shown to reduce hospital length of stay and possibly the need for surgery in SBO patients. The effect of low-osmolar water-soluble contrast challenge however, is unclear. The aim of this study is to evaluate the outcomes of an SBO pathway including a low-osmolar water-soluble contrast challenge. METHODS: A prospective cohort of patients admitted for SBO were placed on an evidence-based SBO pathway including low-osmolar water-soluble contrast between January 2017 and October 2018 and were compared with a historical cohort of patients prior to the implementation of the pathway from September 2013 through December 2014. The primary outcome was length of stay less than 4 days with a secondary outcome of failure of nonoperative management. RESULTS: There were 140 patients enrolled in the SBO pathway during the study period and 101 historic controls. The SBO pathway was independently associated with a length of stay less than 4 days (odds ratio, 1.76; 95% confidence interval, 1.03-3.00). Median length of stay for patients that were successfully managed nonoperatively was lower in the SBO pathway cohort compared with controls (3 days vs. 4 days, p = 0.04). Rates of readmission, surgery, and bowel resection were not significantly different between the two cohorts. CONCLUSION: Implementation of an SBO pathway using a low-osmolarity contrast is associated with decreased hospital length of stay. Rates of readmission, surgery, and need for bowel resection for those undergoing surgery were unchanged. An SBO pathway utilizing low-osmolarity water-soluble contrast is safe and effective in reducing length of stay in the nonoperative management of adhesive small-bowel obstructions. LEVEL OF EVIDENCE: Therapeutic study, level IV.

Contrast-induced encephalopathy after percutaneous peripheral intervention.

Contrast-induced encephalopathy (CIE) is a rare complication of angiography. Presently reported is the case of a patient diagnosed with CIE following peripheral angioplasty with the non-ionic contrast agent, iohexol. A 66-year-old male patient described intermittent claudication and peripheral arterial disease was suspected. Lower extremity angiography was performed, and following dilation of a 7.0x150-mm balloon, a 9.0x57-mm stent was placed in the lesioned vessel. The patient subsequently developed confusion and cortical blindness, and a seizure occurred 1 hour after the procedure. An emergency cerebral computed tomography scan did not reveal any signs of intracerebral hemorrhage. The neurological symptoms disappeared within 24 hours after hydration and sedative medication. CIE was diagnosed based on the patient`s clinical course findings and cerebral imaging.

Iodixanol versus Iopromide at Coronary CT Angiography: Lumen Opacification and Effect on Heart Rhythm-the Randomized IsoCOR Trial.

Purpose To show that equal coronary lumen opacification can be achieved with iso- and low-osmolar contrast media when it is injected at the same iodine delivery rate with contemporary cardiac computed tomographic (CT) protocols and to investigate the cardiovascular effect of iso-osmolar contrast media and the image quality achieved. Materials and Methods Institutional review board approval and written informed consent were obtained for the Effect of Iso-osmolar Contrast Medium on Coronary Opacification and Heart Rhythm in Coronary CT Angiography, or IsoCOR, trial. Between November 2015 and August 2016, 306 patients (167 [55%] women) at least 18 years old (weight range, 50-125 kg), were prospectively randomized to receive iso-osmolar iodixanol 270 or low-osmolar iopromide 300 contrast media. All coronary segments were assessed for intraluminal opacification and image quality and were compared by using the Student t test. Heart rate, arrhythmia, patient discomfort, and adverse events also were monitored. Results Mean measured coronary attenuation values ± standard deviation were comparable between the iodixanol 270 and iopromide 300 contrast media groups (469 HU ± 167 vs 447 HU ± 166, respectively [P = .241]; 95% confidence interval: -15.1, 60.0), including those from subanalyses. Adjusted for the lower iodine concentration, the mean iodixanol 270 bolus was larger compared with that of iopromide 300 (76.8 mL ± 11.6 vs 69.7 mL ± 10.8, respectively; P < .001). The higher injection rate was associated with higher pressure (777 kPa ± 308 vs 630 kPa ± 252, respectively; P < .001). Although in the iodixanol 270 group patients experienced less heat discomfort (72% vs 86%, respectively; P < .001), no differences in heart rate or rhythm were observed. Conclusion If injected at comparable iodine delivery rates, the iso-osmolar contrast medium iodixanol 270 is not inferior to low-osmolar contrast medium iopromide 300 for assessment of coronary opacification. Iodixanol 270 was associated with less heat discomfort, but did not affect heart rate differently compared with iopromide 300. © RSNA, 2017 Online supplemental material is available for this article.

The incidence and significance of acute kidney injury following emergent contrast administration in patients with STEMI and stroke.

The authors have investigated the incidence of acute kidney injury (AKI) and short-term mortality following an activated STEMI and stroke alert at a tertiary referral and academic center. A single center, retrospective chart review of STEMI and stroke activation patients from January 2010 to March 2012. Data was collected and reviewed from an institutional database following IRB-approval. Inclusion criteria were STEMI patients taken for cardiac catheterization, excluding patients receiving hemodialysis due to end-stage renal disease (ESRD). Primary outcome measures were the incidence of AKI using the RIFLE criteria and short-term mortality. 745 patients were included (488 stroke, 257 STEMI). The median age was 65, and 39 % were female. Overall inpatient mortality was 7.0 %. 5.4 % (40/745) of patients experienced some degree of AKI (8.6 % of STEMI, 3.7 % of stroke patients). Overall, 30 % of patients with AKI died during their hospitalization. AKI was associated with a 7.1-fold (95 % CI 3.4-15.1) increase in mortality in the entire cohort. Among STEMI patients, AKI was associated with a 66.6-fold (95 % CI 12.9-343.4) increase in mortality. These findings follow similar trends published among critically ill patients with AKI. The risk of death with concomitant AKI in this hospital population is significant and deserves future study. Early recognition and awareness in the emergency department is paramount to the patient's survival. Future studies should focus on modalities to improve early recognition and preventative therapies.

Chronic kidney disease after heart transplantation: a single-centre retrospective study at Skåne University Hospital in Lund 1988-2010.

We aimed to study the incidence, predictors and outcome of chronic kidney disease (CKD) after heart transplantation (HT). All our HT patients 1988-2010 were considered for inclusion. Of these, 134 came for annual follow-ups including evaluation of glomerular filtration rate (GFR) using iohexol clearance measurements, and the CKD-EPI (adults) or Schwartz (children) formulae. Median GFR (Q1-Q3) (ml/min/1.73 m(2) ) declined from 67.0 (50.0-82.0) during transplant assessment (TA) to 56.0 (45.0-69.0) at year 1, 53.0 (41.0-68.0) at year 5 and 44.5 (25.0-57.3) at year 10. The cumulative incidence of CKD ≥ stage 4 was 25% at 5 years and 41% at 10 years after transplantation. Proteinuria the first year post-HT was the only predictor related (P < 0.05) to a higher rate of GFR decline (HR 5.15, 95% CI 1.23-21.55). GFR ≥60 as compared to <60 before HT, or a first-year GFR decline <30% as compared to >30%, was moreover associated (P < 0.05) with a lower risk of death (HR 0.30, 95% CI 0.12-0.76 and HR 0.35, 95% CI 0.13-0.90, respectively). Notably, the CKD-EPI and Schwartz formulae overestimated GFR by 28 ± 29% and 26 ± 33%, respectively. In conclusion, CKD in HT patients is common and associated with worse outcome. To avoid diagnostic delay, GFR estimating equations' validity in HT patients needs further study.

Temporary organ displacement coupled with image-guided, intensity-modulated radiotherapy for paraspinal tumors.

BACKGROUND: To investigate the feasibility and dosimetric improvements of a novel technique to temporarily displace critical structures in the pelvis and abdomen from tumor during high-dose radiotherapy. METHODS: Between 2010 and 2012, 11 patients received high-dose image-guided intensity-modulated radiotherapy with temporary organ displacement (TOD) at our institution. In all cases, imaging revealed tumor abutting critical structures. An all-purpose drainage catheter was introduced between the gross tumor volume (GTV) and critical organs at risk (OAR) and infused with normal saline (NS) containing 5-10% iohexol. Radiation planning was performed with the displaced OARs and positional reproducibility was confirmed with cone-beam CT (CBCT). Patients were treated within 36 hours of catheter placement. Radiation plans were re-optimized using pre-TOD OARs to the same prescription and dosimetrically compared with post-TOD plans. A two-tailed permutation test was performed on each dosimetric measure. RESULTS: The bowel/rectum was displaced in six patients and kidney in four patients. One patient was excluded due to poor visualization of the OAR; thus 10 patients were analyzed. A mean of 229 ml (range, 80-1000) of NS 5-10% iohexol infusion resulted in OAR mean displacement of 17.5 mm (range, 7-32). The median dose prescribed was 2400 cGy in one fraction (range, 2100-3000 in 3 fractions). The mean GTV Dmin and PTV Dmin pre- and post-bowel TOD IG-IMRT dosimetry significantly increased from 1473 cGy to 2086 cGy (p=0.015) and 714 cGy to 1214 cGy (p=0.021), respectively. TOD increased mean PTV D95 by 27.14% of prescription (p=0.014) while the PTV D05 decreased by 9.2% (p=0.011). TOD of the bowel resulted in a 39% decrease in mean bowel Dmax (p=0.008) confirmed by CBCT. TOD of the kidney significantly decreased mean kidney dose and Dmax by 25% (0.022). CONCLUSIONS: TOD was well tolerated, reproducible, and facilitated dose escalation to previously radioresistant tumors abutting critical structures while minimizing dose to OARs.

Contrast agent induced obliteration of a spinal arteriovenous malformation.

We present a patient undergoing spinal angiography and suspected of having an AVM. During the first injection of nonionic contrast, a nidal AVM supplied by the great anterior radiculomedullary artery at T9 left was found. The second injection at T9 left no longer showed the contrast filling of the AVM. Follow-up angiography showed persistent AVM obliteration with an intact arterial spinal axis. The patient's symptoms resolved. Interaction between nonionic contrast, blood, and vessel wall most likely induced the obliteration.

Assessment of EmboGel--a selectively dissolvable radiopaque hydrogel for embolic applications.

PURPOSE: To evaluate the embolic properties of an alginate-based embolic biomaterial (EmboGel) and its solvent (EmboClear) in treatment of aneurysms. MATERIALS AND METHODS: EmboGel is a mixture of iohexol and alginate that polymerizes into a hydrocoil when delivered through a coaxial catheter with a distal mixing tip, exposing alginate to a calcium chloride solution. In contrast to previously reported embolic agents, EmboGel can be selectively dissolved by EmboClear, a mixture of the enzyme alginate lyase and ethylenediaminetetraacetic acid (EDTA). The embolic and contrast properties of EmboGel were assessed in in vitro models of saccular aneurysm and an aortic aneurysm endoleak. The dissolvability of EmboGel with EmboClear was assessed further after endovascular delivery in the New Zealand white rabbit in the native aortoiliofemoral territory, a created saccular aneurysm, and the native carotid arteries. RESULTS: EmboGel effectively filled aneurysm cavities in the case of stent excluded saccular and fusiform aneurysms. EmboGel was readily dissolved by EmboClear in vitro and after in vivo embolization. When the distal abdominal aorta and pelvic arteries were occluded with EmboGel, within 1 minute of EmboClear infusion, patency of the aorta and most of the pelvic circulation was regained as noted by angiography. Embolization in the subclavian artery and numerous distal branches was rapidly dissolved by EmboClear. Finally, the carotid artery occluded with EmboGel regained patency after administration of EmboClear. CONCLUSIONS: EmboGel is a dissolvable alginate-based biomaterial that can be used for numerous embolic applications. EmboGel can be selectively dissolved with EmboClear, a solution of alginate lyase and EDTA.

In vitro assessment of EmboGel and UltraGel radiopaque hydrogels for the endovascular treatment of aneurysms.

PURPOSE: To describe two hydrogel embolic materials, the alginate-based EmboGel and the polyethylene glycol diacrylate-based UltraGel and examine their use as embolic agents in in vitro models of abdominal aortic aneurysm (AAA) endoleak and saccular aneurysms. MATERIALS AND METHODS: EmboGel is a mixture of iohexol and alginate, with a calcium chloride solution used to induce polymerization. UltraGel is a mixture of igracure, iohexol, and polyethylene glycol diacrylate and polymerizes in the presence of ultraviolet (UV) light. Modified microcatheter delivery systems were used in both cases to demonstrate use of the hydrogels in fusiform and saccular aneurysm models. RESULTS: Preliminary in vitro results suggest that EmboGel and UltraGel provide effective embolization in fusiform and saccular aneurysm models, respectively. Due to the rapid polymerization of EmboGel, the agent was delivered in a strand-like form. When used in conjunction with a stent in an AAA endoleak model, this form was able to effectively fill the aneurysmal cavity and occlude it from the central blood flow. UltraGel, conversely, was delivered as a liquid and slowly polymerized in the presence of UV light. This system in a saccular aneurysm model was able to form a solid cast inside the aneurysm wall, again showing complete occlusion from the parent flow. CONCLUSIONS: Preliminary results indicate these two novel hydrogel applications may prove effective for the treatment of saccular and fusiform aneurysms.

Comparison of delayed enhanced CT and chemical shift MR for evaluating hyperattenuating incidental adrenal masses.

PURPOSE: To retrospectively compare the accuracy of delayed enhanced computed tomography (CT) and chemical shift magnetic resonance (MR) imaging for characterizing hyperattenuating adrenal masses at CT, with either follow-up imaging or pathologic review as the reference standard. MATERIALS AND METHODS: The institutional review board approved this retrospective study with a waiver of patient informed consent. Forty-three hyperattenuating adrenal masses (>10 HU) on unenhanced CT images were found in 34 patients (23 men and 11 women; mean age, 52.7 years) by reviewing radiologic reports. These lesions were retrospectively analyzed with delayed enhanced CT and chemical shift MR. The diagnostic accuracy of CT by using absolute percentage loss of enhancement (PLE) and relative PLE and of chemical shift MR by using adrenal-to-spleen ratio (ASR) or signal intensity index (SII) were obtained to determine which modality was more accurate for lipid-poor adenoma. For CT, an adenoma was diagnosed if a mass had an absolute PLE greater than 60% and a relative PLE greater than 40%. For MR, an adenoma was diagnosed if a mass had an ASR of 0.71 or an SII greater than 16.5%. McNemar test was used to compare diagnostic performance of CT and MR. RESULTS: Hyperattenuating adrenal masses included 37 adenomas and six nonadenomas. The sensitivity, specificity, and accuracy for adenoma at CT were 97% (36 of 37), 100% (six of six), and 98% (42 of 43), respectively, and at MR were 86% (32 of 37), 50% (three of six), and 49% (21 of 43), respectively. CT helped confirm five more adenomas and three more metastatic tumors than did MR. However, there was no significant difference for diagnostic accuracy between these two imaging modalities (P>.05) CONCLUSION: Delayed enhanced CT can characterize additional hyperattenuating adrenal masses that cannot be characterized with chemical shift MR.

In vivo comparative antithrombotic effects of ioxaglate and iohexol and interaction with the platelet antiaggregant clopidogrel.

RATIONALE AND OBJECTIVES: Experiments were designed to (1) compare the effects of iodinated contrast media (CM) on a rat model of arterial thrombosis, (2) evaluate which element of the ioxaglate solution supports its antithrombotic activity, and (3) investigate the interaction of ionic and non-ionic CM with the antiplatelet agent clopidogrel. MATERIALS AND METHODS: Carotid thrombosis was induced in rats by extravascular application of a filter paper soaked in FeCl3 (35% vol/wt), proximal to an ultrasonic flow probe. (1) The antithrombotic potential of low-osmolar ionic (ioxaglate Na/meglumine) or nonionic contrast media (iohexol and iodixanol) (all 1600 mg iodine/kg, IV) was assessed by measuring the time to occlusion (TTO) of the carotid artery and the thrombus weight (TW). (2) Isotonic saline and iso-osmolar (280 mOsm/kg) and hyperosmolar (560 mOsm/kg) solutions of meglumine hydrochloride, meglumine ioxaglate (560 mOsm/kg), sodium ioxaglate (600 mOsm/kg) and sodium and meglumine ioxaglate (commercial solution) were tested under similar conditions. (3) Interaction with clopidogrel was tested by injecting lower dose of CM (960 mg iodine/kg) 2 hours after clopidogrel (2 mg/kg per os). RESULTS: (1) Ioxaglate prolonged TTO when compared with saline (30.0 +/- 1.1 minute vs. 19.6 +/- 2.4 minutes, P< 0.001), whereas iohexol had no effect (21.3 +/- 1.3 minutes). Ioxaglate's effect was associated with a reduction in TW with ioxaglate versus saline (2.6 +/- 0.4 mg and 4.7 +/- 0.7 mg, respectively, P< 0.05) whereas TW remained unchanged in the iohexol group (4.2 +/- 0.4 mg). The nonionic dimer iodixanol induced a direct vasoconstrictor effect on the carotid artery and was consequently excluded from the study. (2) Neither iso-osmolar nor hyperosmolar solutions of meglumine had any effect on TTO whereas both sodium and meglumine salts of ioxaglic acid prolonged TTO, suggesting that the antithrombotic effect of ioxaglate is mediated by the ioxaglic acid moiety alone as neither meglumine, osmolality or sodium played a significant role. (3) A synergistic effect on TTO was found when ioxaglate was associated with clopidogrel whereas no such effect was observed with iohexol. CONCLUSIONS: These data show a greater in vivo antithrombotic potential for the ionic contrast medium ioxaglate than for the non-ionic contrast medium iohexol and, for the first time, a synergistic effect between a contrast medium and a platelet antiaggregant drug in vivo.

Application of transarterial embolization of renal artery in rabbits with experimental hydronephrosis.

This study was performed to validate the procedure of transarterial embolization of the renal artery (TAE-RA) using iohexol-ethanol solution in rabbits with unilateral experimental hydronephrosis and to evaluate the embolized kidney and contralateral normal kidney using B-mode ultrasonography and color Doppler ultrasonography. Experimental hydronephrosis was induced at 17 days after ligation of unilateral ureter in 13 rabbits. Renal artery embolization was performed using selective catheterization in the hydronephrotic kidney of eight rabbits and electrocardiography, oxygen saturation, body temperature, pulse, and respiratory rate were within normal ranges during procedures. Iohexol-ethanol solution was used as embolic material. Average ethanol dose for renal artery embolization was 1.4 +/- 0.7 ml/kg. There were no rabbits expired after TAE-RA and no side effects associated with regurgitation of iohexol-ethanol solution. In color Doppler ultrasonographic findings, there was no blood flow into the embolized kidneys treated by TAE-RA, however, blood flow signal was found in hydronephrotic kidney not treated by TAE-RA. Ultrasonographically, the mean longitudinal length of the embolized kidney significantly decreased at 2 and 3 months after TAE-RA. No significant difference of resistive index values was found between contralateral normal kidney of rabbits treated by TAE-RA and contralateral normal kidneys of rabbits treated with nephrectomy. We may conclude that TAE-RA with iohexol-ethanol solution is a viable alternative to nephrectomy in rabbits with unilateral hydronephrosis.

Antithrombotic effects of ionic and non-ionic contrast media in nonhuman primates.

Thromboembolic complications have been attributed to the use of radiographic contrast media (CM) during interventional procedures for arterial revascularization. However, due to the low frequency of adverse events, comparisons between different CM have been difficult to perform, although it has been suggested that ionic (vs. non-ionic) CM may be associated with fewer thrombotic events. The present study was undertaken using well-characterized baboon thrombosis models in order to compare different CM under physiologically relevant and controlled conditions of blood flow, exposure time, and CM concentration. Three CM were studied: ioxaglate, iohexol, and iodixanol. CM were locally infused into the proximal segment of femoral arteriovenous shunts. Palmaz-Schatz stents (4 mm i.d.) and expanded tubular segments (9 mm i.d.), which exhibited venous-type flow recirculation and stasis, were deployed into the shunts distally. Saline was infused in identical control studies. Blood flow was maintained at 100 ml/min. Thrombosis was measured over a blood exposure period of 2 hours by gamma camera imaging of 111In-platelets and by gamma counting of deposited 125I-fibrin. CM concentrations within the flowfield were predicted using computational fluid dynamics. At infusion rates of 0.1 and 0.3 ml/min, the low-osmolar ionic CM ioxaglate reduced both platelet and fibrin deposition on the stents by 75-80% (p <0.005), while both iohexol and iodixanol reduced platelet deposition by 30-50% (p <0.05). In the regions of low shear flow, ioxaglate (0.3 ml/min) also reduced platelet deposition significantly (by 52% vs. control results; p <0.05). Thus the three agents evaluated--ioxaglate, iohexol, and iodixanol--all produced anticoagulant and antiplatelet effects and were inherently antithrombotic in vivo. The most striking effects were seen with the low osmolarity, ionic contrast agent ioxaglate.

[Splenectomy by celioscopy. Experience of 20 cases]. / Splénectomie par voie coelioscopique. Expérience de vingt cas.

We describe the clinical course of 20 patients considered for laparoscopic splenectomy. One patient was excluded on the basis of preoperative angiography findings and two (10.5%) were converted to open surgery. The first patient in the series was converted for a hemorrhagic incident and the eight patient, who had a 34 cm spleen, for dissection difficulties. In the remaining 17 patients who successfully underwent laparoscopic splenectomy, no mortality was reported and there were four postoperative complications (23.5%). Mean operating time was 3 h 40 min (135-300 min). After a mean postoperative stay of four days, all patients, except two, were back to normal activities within 2 weeks of hospital discharge. Preoperative splenic artery embolization was begun with the third patient and was found to significantly reduce operative blood loss and make the procedure easier to perform. Laparoscopic splenectomy has become our procedure of choice for elective removal of normal-sized or moderately enlarged spleens.

Intraocular radiation blocking.

Iodine-based liquid radiographic contrast agents were placed in normal and tumor-bearing (Greene strain) rabbit eyes to evaluate their ability to block iodine-125 radiation. This experiment required the procedures of tumor implantation, vitrectomy, air-fluid exchange, and 125I plaque and thermoluminescent dosimetry (TLD) chip implantation. The authors quantified the amount of radiation attenuation provided by intraocularly placed contrast agents with in vivo dosimetry. After intraocular insertion of a blocking agent or sham blocker (saline) insertion, episcleral 125I plaques were placed across the eye from episcleral TLD dosimeters. This showed that radiation attenuation occurred after blocker insertion compared with the saline controls. Then computed tomographic imaging techniques were used to describe the relatively rapid transit time of the aqueous-based iohexol compared with the slow transit time of the oil-like iophendylate. Lastly, seven nontumor-bearing eyes were primarily examined for blocking agent-related ocular toxicity. Although it was noted that iophendylate induced intraocular inflammation and retinal degeneration, all iohexol-treated eyes were similar to the control eyes at 7 and 31 days of follow-up. Although our study suggests that intraocular radiopaque materials can be used to shield normal ocular structures during 125I plaque irradiation, a mechanism to keep these materials from exiting the eye must be devised before clinical application.