Balloon-Assisted Portal Vein Embolization Using n-Butyl-2-Cyanoacrylate-Lipiodol-Iopamidol Mixture in Swine: A Comparison of 2 Formulations.

PURPOSE: To compare 2 ratios of n-butyl-2-cyanoacrylate (nBCA)-ethiodized oil (Lipiodol)-iopamidol (NLI) in balloon-assisted portal vein embolization (PVE) in swine. MATERIALS AND METHODS: In an in vitro study, NLI prepared at a ratio of 2:3:1 (NLI231) or 1:4:1 (NLI141) was injected into 2.5- or 10-mL syringes filled with swine blood, and the viscosity of NLI was measured to determine an appropriate balloon occlusion time. Two portal vein branches in 8 female swine (n = 16 vein branches) were embolized with NLI231 (n = 8) or NLI141 (n = 8) under balloon occlusion. Portal venography was performed before, immediately after, and 3 days after PVE to evaluate the migration of NLI and the recanalization of embolized portal vein branches. Then, the livers were removed for histopathologic evaluation. RESULTS: The times to peak viscosity of NLI231 in the 2.5- and 10-mL syringes were 55.8 seconds (SD ± 7.0) and 85.2 seconds (SD ± 6.3), and those to peak viscosity of NLI141 were 129.2 seconds (SD ± 11.8) and 254.0 seconds (SD ± 21.8), respectively. No migration of NLI231 was observed in all 8 procedures immediately or 3 days after PVE. Migration of NLI141 was observed in 6 of 8 procedures within 3 days after PVE. The migration frequency of the embolic material was lower in the NI231 group than in the NLI141 group (0/8 vs 6/8; P = .051). Histologically, NLI231 occupied the portal veins without any thrombi, whereas NLI141 was accompanied by thrombi in the portal veins. CONCLUSIONS: NLI231 may be more suitable than NLI141 for balloon-assisted PVE in swine.

Transient pulmonary and gastric bleeding after iopamidol administration in a patient with marginal zone lymphoma: a case report.

BACKGROUND: Iopamidol is a non-ionic, water-soluble iodine contrast agent that is considered safe for intravenous or intra-arterial administration and is widely used both in the general population and in patients undergoing oncological treatment. While adverse reactions to iopamidol have been documented, to date, no pulmonary and gastric hemorrhages induced by iopamidol have been reported in oncology patients. We report the first case of this complication. CASE PRESENTATION: We report the case of a 60-year-old woman with marginal zone lymphoma who was receiving antineoplastic therapy. As part of the investigation for the condition, she underwent chest enhancement CT with iopamidol. Shortly thereafter(within five minutes), she experienced hemoptysis and hematemesis. She was intubated and admitted to the intensive care unit. Pre- and post-contrast images demonstrated the course of the hemorrhage. Flexible bronchoscopy and gastroscopy on the following day showed no active bleeding, and the patient recovered completely after antiallergy treatment. We speculate that contrast-induced hypersensitivity was the most likely cause of the transient pulmonary and gastric bleeding. CONCLUSION: Although rare, the complications of iopamidol, which may cause allergic reactions in the lungs and stomach, should be considered.

Monitoring Pharmaceuticals and Personal Care Products in Healthcare Effluent Wastewater Samples and the Effectiveness of Drug Removal in Wastewater Treatment Plants Using the UHPLC-MS/MS Method.

A multi-residue UHPLC-MS/MS analytical method, previously developed for monitoring 52 pharmaceuticals in drinking water, was used to analyse these pharmaceuticals in wastewater originating from healthcare facilities in the Czech Republic. Furthermore, the methodology was expanded to include the evaluation of the effectiveness of drug removal in Czech wastewater treatment plants (WWTPs). Of the 18 wastewater samples analysed by the validated UHPLC-MS/MS, each sample contained at least one quantifiable analyte. This study reveals the prevalence of several different drugs; mean concentrations of 702 µg L-1 of iomeprol, 48.8 µg L-1 of iopromide, 29.9 µg L-1 of gabapentin, 42.0 µg L-1 of caffeine and 82.5 µg L-1 of paracetamol were present. An analysis of 20 samples from ten WWTPs revealed different removal efficiencies for different analytes. Paracetamol was present in the inflow samples of all ten WWTPs and its removal efficiency was 100%. Analytes such as caffeine, ketoprofen, naproxen or atenolol showed high removal efficiencies exceeding 80%. On the other hand, pharmaceuticals like furosemide, metoprolol, iomeprol, zolpidem and tramadol showed lower removal efficiencies. Four pharmaceuticals exhibited higher concentrations in WWTP effluents than in the influents, resulting in negative removal efficiencies: warfarin at -9.5%, indomethacin at -53%, trimethoprim at -54% and metronidazole at -110%. These comprehensive findings contribute valuable insights to the pharmaceutical landscape of wastewater from healthcare facilities and the varied removal efficiencies of Czech WWTPs, which together with the already published literature, gives a more complete picture of the burden on the aquatic environment.

A machine learning approach that measures pH using acidoCEST MRI of iopamidol.

Tumor acidosis is an important biomarker for aggressive tumors, and extracellular pH (pHe) of the tumor microenvironment can be used to predict and evaluate tumor responses to chemotherapy and immunotherapy. AcidoCEST MRI measures tumor pHe by exploiting the pH-dependent chemical exchange saturation transfer (CEST) effect of iopamidol, an exogenous CT agent repurposed for CEST MRI. However, all pH fitting methodologies for acidoCEST MRI data have limitations. Herein we present results of the application of machine learning for extracting pH values from CEST Z-spectra of iopamidol. We acquired 36,000 experimental CEST spectra from 200 phantoms of iopamidol prepared at five concentrations, five T1 values, and eight pH values at five temperatures, acquired at six saturation powers and six saturation times. We also acquired T1 , T2 , B1 RF power, and B0 magnetic field strength supplementary MR information. These MR images were used to train and validate machine learning models for the tasks of pH classification and pH regression. Specifically, we tested the L1-penalized logistic regression classification (LRC) model and the random forest classification (RFC) model for classifying the CEST Z-spectra for thresholds at pH 6.5 and 7.0. Our results showed that both RFC and LRC were effective for pH classification, although the RFC model achieved higher predictive value, and improved the accuracy of classification accuracy with CEST Z-spectra with a more limited set of saturation frequencies. Furthermore, we used LASSO and random forest regression (RFR) models to explore pH regression, which showed that the RFR model achieved higher accuracy and precision for estimating pH across the entire pH range of 6.2-7.3, especially when using a more limited set of features. Based on these results, machine learning for analysis of acidoCEST MRI is promising for eventual in vivo determination of tumor pHe.

Nephrotoxicity of iopamidol is associated with mitochondrial impairment in human cell and teleost models.

Iopamidol is a nonionic, low-osmolar iodinated contrast agent used for angiography. Its clinical use is associated with renal dysfunction. Patients suffering from preexisting kidney disease have an increased risk of renal failure upon iopamidol administration. Studies in animals confirmed renal toxicity, but the involved mechanisms remain unclear. Therefore, the aim of the present study was to use human embryonic kidney cells (HEK293T) as a general cell model of mitochondrial damage, as well as, zebrafish larvae, and isolated proximal tubules of killifish to investigate factors promoting renal tubular toxicity of iopamidol with a focus on mitochondrial damage. Results from in vitro HEK293T cell-based assays indicate that iopamidol affects mitochondrial function Treatment with iopamidol induces ATP depletion, reduces the mitochondrial membrane potential, and elevates mitochondrial superoxide and reactive oxygen species accumulation. Similar results were obtained with gentamicin sulfate and cadmium chloride, two well-known model compounds associated with renal tubular toxicity. Confocal microscopy confirms changes in mitochondrial morphology, such as mitochondrial fission. Importantly, these results were confirmed in proximal renal tubular epithelial cells using ex vivo and in vivo teleost models. In conclusion, this study provides evidence for iopamidol-induced mitochondrial damage in proximal renal epithelial cells. Teleost models allow studying proximal tubular toxicity with translational relevance for humans.

Contrast Agent Selection to Prevent Recurrent Severe Hypersensitivity Reaction to Iodinated Contrast Media Based on Nationwide Database.

OBJECTIVE: To investigate the incidence of severe iodinated contrast media (ICM)-related hypersensitivity reaction (HSR) and to find the optimal alternative ICM to reduce the risk of severe HSR recurrence. METHODS: We retrospectively reviewed 23,383,183 cases of ICM administration between January 2015 and December 2019 from the nationwide health insurance database. We classified ICMs based on generic profiles and the presence of N-(2,3-dihydroxypropyl) carbamoyl side chains. The incidence of severe and recurrent severe HSRs was calculated, and χ2 tests were performed to compare the prevalence of severe HSR according to ICM groups. In addition, logistic regression analyses were used to assess differences between ICM groups. RESULTS: The incidence of severe HSRs was 1.92% (450,067 of 23,282,183). Among 1,875,245 individuals who received ICM twice on different days, severe HSR occurred in 40,850 individuals, and severe HSR recurred in 3319 individuals (8.12%). The risk of recurrence significantly decreased when the ICM changed (9.24% vs 7.08%, P < 0.001), especially when the ICM changed to one with a different side chain (6.74%, P < 0.001). In addition, compared with the reuse of the culprit agent, using combinations of iobitridol/iohexol (odds ratio [OR], 0.696; P = 0.04), iohexol/iopamidol (OR, 0.757; P = 0.007), iopamidol/iohexol (OR, 0.447; P < 0.001), and ioversol/iohexol (OR, 0.683; P = 0.04) reduced the risk of recurrence of severe HSR. CONCLUSIONS: Changing the culprit ICM to that with a different side chain can reduce severe HSR recurrence. The optimal choice of an alternative ICM depends on the causative agent.

Dual-Energy CT Perfusion of Invasive Tumor Front in Non-Small Cell Lung Cancers.

Background Active endothelial cell proliferation occurs at the tumor edge, known as the invading-tumor front. This study focused on perfusion analysis of non-small cell lung cancers. Purpose To analyze dual-phase, dual-energy CT perfusion according to the degree of tumor hypoxia. Materials and Methods This prospective study was performed 2016-2017. A two-phase dual-energy CT protocol was obtained for consecutive participants with operable non-small cell lung cancer. The first pass and delayed iodine concentration within the tumor and normalized iodine uptake, corresponding to the iodine concentration within the tumor normalized to iodine concentration within the aorta, were calculated for the entire tumor and within three peripheral layers automatically segmented (ie, 2-mm-thick concentric subvolumes). The expression of the membranous carbonic anhydrase (mCA) IX, a marker of tumor hypoxia, was assessed in tumor specimens. Comparative analyses according to the histologic subtypes, type of resected tumors, and mCA IX expression were performed. Results There were 33 mCA IX-positive tumors and 16 mCA IX-negative tumors. In the entire tumor, the mean normalized iodine uptake was higher on delayed than on first-pass acquisitions (0.35 ± 0.17 vs 0.13 ± 0.15, respectively; P < .001). A single layer, located at the edge of the tumor, showed higher values of the iodine concentration (median, 0.53 mg/mL vs 0.21 mg/mL, respectively; P = .03) and normalized iodine uptake (0.04 vs 0.02, respectively; P = .03) at first pass in mCA IX-positive versus mCA IX-negative tumors. Within this layer, a functional profile of neovascularization was found in 23 of 33 (70%) of mCA IX-positive tumors, and the median mCA IX score of these tumors was higher than in tumors with a nonfunctional profile of neovascularization (median mCA IX score, 20 vs 2, respectively; P = .03). Conclusion A two-phase dual-energy CT examination depicted higher perfusion between the tumor edge and lung parenchyma in hypoxic tumors. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Murphy and Ryan in this issue.

Non-immediate hypersensitivity reactions to iomeprol: Diagnostic value of skin tests and cross-reactivity with other iodinated contrast media.

BACKGROUND: Iodinated contrast media produce non-immediate hypersensitivity reactions (NIHR). The goal of this prospective study was to determine the utility of skin tests and the subsequent tolerance to negative skin-tested iodinated contrasts in patients with NIHR caused by iomeprol. METHODS: Prick and intradermal tests with iomeprol, iopamidol, iopromide, and iobitridol were performed in all patients. IV challenge with the causative contrast (iomeprol in 90%) was made if skin tests were negative. In case of a positive skin test with the causal contrast, or a positive challenge test with it, IV challenge test with an alternative, negative skin-tested contrast was performed in all patients. RESULTS: Skin tests were positive in 47.6% (20/42) of patients with NIHR induced by iomeprol. Of the 66 challenge tests performed with negative skin-tested iodinated contrasts, tolerance was confirmed in 35 (53%): 32 iomeron, 2 iobitridol, 1 iopamidol. Cross-reactivity between iomeprol and iopamidol was 22% (4/20 in patients with positive skin tests and 5/21 in patients with negative skin tests). CONCLUSIONS: Sensitivity of the skin tests was less than 50% NIHRs due to iomeprol, while the negative predictive value of skin tests in patients who tolerated challenges with alternative contrasts (mainly iopamidol) was 53% (35 tolerated out of 66 performed). The cross-reactivity between iomeprol and iopamidol is high.

Optimized Bolus Threshold for Dual-Energy CT Angiography with Monoenergetic Images: A Randomized Clinical Trial.

Background The bolus-tracking technique from single-energy CT has been applied to dual-energy CT (DECT) without optimization or validation. Further optimization is imperative because of a paucity of literature and differences in the attenuation profile of virtual monoenergetic images (VMIs). Purpose To determine the optimal trigger threshold with bolus-tracking technique for DECT angiography (DECTA) in a phantom study and assess the feasibility of an optimized threshold for bolus-tracking technique in DECTA at 40 keV with a 50% reduced iodine dose in human participants. Materials and Methods A phantom study with rapid kilovoltage-switching DECT was performed to determine the optimal threshold for each kiloelectron-volt VMI. In a prospective study, consecutive participants who underwent whole-body CT angiography (CTA) from August 2018 to July 2019 were randomized into three groups: single-energy CTA (SECTA) with standard iodine dose (600 mg of iodine per kilogram), DECTA with 50% reduced iodine dose (300 mg of iodine per kilogram) by using a conventional threshold, and DECTA with 300 mg of iodine per kilogram by using an optimized threshold. A trigger threshold of 100 HU at 120 kVp was used as a reference for comparison. Injected iodine doses and aortic CT numbers were compared among the three groups using Kruskal-Wallis test. Results Ninety-six participants (mean age ± standard deviation, 72 years ± 9; 80 men) were evaluated (32 participants in each group). The optimized threshold for VMIs at 40 keV was 30 HU. The median iodine dose was lower in the optimized DECTA group (13 g) compared with conventional DECTA (19 g) and SECTA (26 g) groups (P < .017 for each comparison). The median aortic CT numbers were higher in the order corresponding to conventional DECTA (655-769 HU), optimized DECTA (543-610 HU), and SECTA (343-359 HU) groups (P < .001). Conclusion The optimized trigger threshold of 30 HU for bolus-tracking technique during dual-energy CT angiography at 40 keV achieved lower iodine load while maintaining aortic enhancement. ©RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Malayeri in this issue.

Case 290: Intravascular Cystic Synovial Sarcoma.

History A 26-year-old man presented with a 1-month history of chest pain, a palpable and painful right inguinal mass, and edema in the right lower extremity. One month earlier, he started to experience left chest pain with no cough. Pulmonary CT angiography (CTA) revealed a left lower lobe segmental pulmonary embolus. The local hospital made a diagnosis of pulmonary embolism. He received anticoagulants, and his chest pain was gradually relieved. At the time of current presentation, the patient was experiencing right lower extremity swelling and pain. Physical examination revealed a 4 × 3 cm palpable right inguinal mass with no redness. His medical history and family history were negative. The results of laboratory work-up were normal, with a d-dimer level of 0.16 mg/L fibrinogen equivalent units (reference range, <0.46 mg/L) and an international normalized ratio of 2.45 (therapeutic range, 2.0-3.0 for a patient taking warfarin), except the prothrombin time was 28.2 seconds (reference range, 9.6-12.8 seconds) and the activated partial thromboplastin time was 52.2 seconds (reference range, 24.8-33.8 seconds). Echocardiography, chest radiography, chest CT, and contrast-enhanced (CE) CT revealed no abnormalities. The patient underwent right lower extremity vascular conventional US (Philips IU22; Philips) with an L9-3 probe (3-9 MHz, venous condition) and contrast-enhanced US (1.5-2.0 mL, SonoVue; Bracco) with an intravenous bolus injection at the initial evaluation. Two days later, noncontrast and contrast-enhanced CT images of the lower abdomen (1.5 mL per kilogram of body weight, 300 mg/mL iomeprol, Iomeron; Bracco) were acquired for further evaluation.

A fast multislice sequence for 3D MRI-CEST pH imaging.

PURPOSE: Chemical exchange saturation transfer MRI can provide accurate pH images, but the slow scan time (due to long saturation periods and multiple offsets sampling) reduce both the volume coverage and spatial resolution capability, hence the possibility to interrogate the heterogeneity in tumors and organs. To overcome these limitations, we propose a fast multislice CEST-MRI sequence with high pH accuracy and spatial resolution. METHODS: The sequence first uses a long saturation pulse to induce the steady-state CEST contrast and a second short saturation pulse repeated after each image acquisition to compensate for signal losses based on an uneven irradiation scheme combined with a single-shot rapid acquisition with refocusing echoes readout. Sequence sensitivity and accuracy in measuring pH was optimized by simulation and assessed by in vitro studies in pH-varying phantoms. In vivo validation was performed in two applications by acquiring multislice pH images covering the whole tumors and kidneys after iopamidol injection. RESULTS: Simulated and in vivo data showed comparable contrast efficiency and pH responsiveness by reducing saturation time. The experimental data from a homogeneous, pH-varying, iopamidol-containing phantom show that the sequence produced a uniform CEST contrast across slices and accurate values across slices in less than 10 minutes. In vivo measurements allowed us to quantify the 3D pH gradients of tumors and kidneys, with pH ranges comparable with the literature. CONCLUSION: The proposed fast multislice CEST-MRI sequence allows volumetric acquisitions with good pH sensitivity, accuracy, and spatial resolution for several in vivo pH imaging applications.

Evaluation of a similarity anisotropic diffusion denoising approach for improving in vivo CEST-MRI tumor pH imaging.

PURPOSE: Chemical exchange saturation transfer MRI provides new approaches for investigating tumor microenvironment, including tumor acidosis that plays a key role in tumor progression and resistance to therapy. Following iopamidol injection, the detection of the contrast agent inside the tumor tissue allows measurements of tumor extracellular pH. However, accurate tumor pH quantifications are hampered by the low contrast efficiency of the CEST technique and by the low SNR of the acquired CEST images, hence in a reduced detectability of the injected agent. This work aims to investigate a novel denoising method for improving both tumor pH quantification and accuracy of CEST-MRI pH imaging. METHODS: An hybrid denoising approach was investigated for CEST-MRI pH imaging based on the combination of the nonlocal mean filter and the anisotropic diffusion tensor method. The denoising approach was tested in simulated and in vitro data and compared with previously reported methods for CEST imaging and with established denoising approaches. Finally, it was validated with in vivo data to improve the accuracy of tumor pH maps. RESULTS: The proposed method outperforms current denoising methods in CEST contrast quantification and detection of the administered contrast agent at several increasing noise levels with simulated data. In addition, it achieved a better pH quantification in in vitro data and demonstrated a marked improvement in contrast detection and a substantial improvement in tumor pH accuracy in in vivo data. CONCLUSION: The proposed approach effectively reduces the noise in CEST images and increases the sensitivity detection in CEST-MRI pH imaging.

Detection of Perfusion Deficits in Multiphase Computed Tomography Angiography-A Stroke Imaging Technique Based on Iodine Mapping on Spectral Computed Tomography: Initial Findings.

OBJECTIVE: The purpose of this study was to explore a novel method for brain tissue differentiation using quantitative analysis of multiphase computed tomography (CT) angiography (MP-CTA) on spectral CT, to assess whether it can distinguish underperfused from normal tissue, using CT perfusion (CTP) as reference. METHODS: Noncontrast CT and MP-CTA images from 10 patients were analyzed in vascular regions through measurements of Hounsfield unit (HU) at 120 kV, HU at 40 keV, and iodine density. Regions were categorized as normal or ischemic according to CTP. Hounsfield unit and iodine density were compared regarding ability to separate normal and ischemic tissue, the difference in maximum time derivative of the right over left hemisphere ratio. RESULTS: Iodine density had the highest maximum time derivatives and generated the largest mean separation between normal and ischemic tissue. CONCLUSIONS: The method can be used to categorize tissue as normal or underperfused. Using iodine quantification seems to give a more distinct differentiation of perfusion defects compared with conventional HU.

Imaging features of sentinel lymph node mapped by multidetector-row computed tomography lymphography in predicting axillary lymph node metastasis.

INTRODUCTION: Accurately assessing axillary lymph node (ALN) status in breast cancer is vital for clinical decision making and prognosis. The purpose of this study was to evaluate the predictive value of sentinel lymph node (SLN) mapped by multidetector-row computed tomography lymphography (MDCT-LG) for ALN metastasis in breast cancer patients. METHODS: 112 patients with breast cancer who underwent preoperative MDCT-LG examination were included in the study. Long-axis diameter, short-axis diameter, ratio of long-/short-axis and cortical thickness were measured. Logistic regression analysis was performed to evaluate independent predictors associated with ALN metastasis. The prediction of ALN metastasis was determined with related variables of SLN using receiver operating characteristic (ROC) curve analysis. RESULTS: Among the 112 cases, 35 (30.8%) cases had ALN metastasis. The cortical thickness in metastatic ALN group was significantly thicker than that in non-metastatic ALN group (4.0 ± 1.2 mm vs. 2.4 ± 0.7 mm, P < 0.001). Multi-logistic regression analysis indicated that cortical thickness of > 3.3 mm (OR 24.53, 95% CI 6.58-91.48, P < 0.001) had higher risk for ALN metastasis. The best sensitivity, specificity, negative predictive value(NPV) and AUC of MDCT-LG for ALN metastasis prediction based on the single variable of cortical thickness were 76.2%, 88.5%, 90.2% and 0.872 (95% CI 0.773-0.939, P < 0.001), respectively. CONCLUSION: ALN status can be predicted using the imaging features of SLN which was mapped on MDCT-LG in breast cancer patients. Besides, it may be helpful to select true negative lymph nodes in patients with early breast cancer, and SLN biopsy can be avoided in clinically and radiographically negative axilla.

Standardization of conventional chemoembolization for hepatocellular carcinoma.

INTRODUCTION AND OBJECTIVES: Conventional transarterial chemoembolization (cTACE) has several limitations due to the lack of standardization. The aim of this study was to evaluate the chemical and physical characteristics and behaviors over time of emulsions for cTACE and to assess intra- and inter-operator variabilities in the preparation processes. MATERIALS AND METHODS: This in vitro study involved evaluation of emulsions for cTACE prepared using two methods: water-in-oil (WiO) and chemotherapeutic-in-oil (CiO). Three emulsions were prepared with each method and obtained after 20, 50, and 100 pumping exchanges. A drop from each final mixture was analyzed via light microscopy (time 1) and after 5, 10, 15, and 20min since the end of preparation. After 20min, all preparations were re-mixed and new drops were re-evaluated. The intra- and inter-operator variabilities were analyzed. RESULTS: The mean droplet diameter decreased non-significantly when the number of pumping exchanges increased and increased significantly over time for both WiO and CiO. The droplets returned to their initial diameters after re-mixing. There were no significant differences in the intra- and inter-operator variabilities (P>0.01). CONCLUSIONS: Any interventional radiologist, regardless of their experience, may prepare these emulsions. These data may represent a set of instructions to standardize cTACE.

Do we really need the arterial phase on CT in pelvic trauma patients?

PURPOSE: To evaluate whether an arterial phase scan improves the diagnostic performance of computed tomography to identify pelvic trauma patients who received angiographic intervention on demand of the trauma surgeon. METHODS: This retrospective single-center study was performed at an academic Scandinavian trauma center with approximately 2000 trauma admissions annually. Pelvic trauma patients with arterial and portal venous phase CT from 2009 to 2015 were included. The patients were identified from the institutional trauma registry. Images were interpreted by two radiologists with more than 10 years of trauma radiology experience. Positive findings for extravasation on portal venous phase alone or on both arterial and portal venous phase were compared, with angiographic intervention as clinical outcome. RESULTS: One hundred fifty-seven patients (54 females, 103 males) with a median age of 45 years were enrolled. Sixteen patients received angiographic intervention. Positive CT findings on portal venous phase only had a sensitivity and specificity of 62% and 86%, vs. 56% and 93% for simultaneous findings on arterial and portal venous phase. Specificity was significantly higher for positive findings in both phases compared with portal venous phase only. Applying a threshold > 0.9 cm of extravasation diameter to portal venous phase only resulted in sensitivity and specificity identical to those of both phases. CONCLUSION: Arterial phase scan in addition to portal venous phase scan did not improve patient selection for angiography. Portal venous phase extravasation size alone may be used as an imaging-based biomarker of the need for angiographic intervention.

Incidence and clinical impact of lower extremity vascular injuries in the setting of whole body computed tomography for trauma.

PURPOSE: The aims of this study are to determine the incidence of lower extremity fractures and/or vascular injuries in the setting of whole body computed tomography (WBCT) for trauma and to determine lower extremity injury outcomes in this patient population. METHODS: This is a retrospective observational study performed at a large urban Level 1 trauma center. Our institutional trauma registry was queried for patients who were evaluated with WBCT and lower extremity CT angiography (CTA) as a part of their initial imaging evaluation over a 43-month period. Patients with lower extremity fractures and/or vascular injuries were identified. Those patients with both lower extremity vascular injury and fracture were then analyzed to determine the physical relationship of the fracture to the vascular injury. Physical exam findings were extracted from the medical record. Interventions and long-term outcomes were determined from the medical record. RESULTS: A total of 370 patients met the inclusion criteria, with 98% experiencing blunt trauma. Of these, 290 (78.4%) were positive for lower extremity injury, including 266 (71.9%) with isolated fractures, 2 (0.6%) with isolated vascular injury, and 22 (5.9%) with vascular injury associated with long bone fracture. Of the 22 patients with combined fracture and vascular injury, 8 received vascular intervention and 10 had long-term complications as a result of their injuries. Physical exam findings were insufficient to diagnose 57% of the vascular injuries. CONCLUSIONS: The inclusion of lower extremity CTA as part of a WBCT imaging exam for trauma allows for the identification of vascular injuries that otherwise may have gone undetected or resulted in delayed diagnosis. Clinically occult lower extremity vascular injuries may be associated with poor outcomes.

MR imaging of cerebral involvement of Rosai-Dorfman disease: a single-centre experience with review of the literature.

Rosai-Dorfman disease (RDD) is a rare, benign, non-Langerhans cells histiocytosis with massive lymphadenopathy of uncertain aetiology. It is commonly characterized by massive, painless, non-tender, bilateral cervical lymphadenopathy. Extra-nodal involvement is usually seen in 50% of patients, with the brain being affected in only 5% of cases, usually as dural-based lesions. Clinical presentation is heterogeneous and strongly dependent on the localization of the lesions. Although the histopathological findings are essential for the final diagnosis, brain magnetic resonance imaging (MRI) currently represents the first-line strategy for the detection of the lesions across the central nervous system (CNS); moreover, it may provide additional elements for the differential diagnosis versus other more common lesions. We performed a case-based literature review to highlight possible aetiologic and pathogenetic theories of this disease, along with imaging features of RDD, with a particular focus on the MRI characteristics of the CNS involvement (CNS-RDD). Finally, we provided a novel insight on the current therapeutic approaches, either surgical or medical.

The Establishment of an Optimal Protocol for Contrast-Enhanced Micro-Computed Tomography in the Cloudy Catshark Scyliorhinus torazame.

The purpose of this study was to determine the optimal imaging protocol for contrast-enhanced computed tomography (CECT) using micro-CT (µ-CT) for the posterior cardinal vein (PCV), dorsal aorta (DA), hepatic portal vein (HPV), kidney, liver, cephalic arteries (CAs), and gills of Cloudy Catsharks Scyliorhinus torazame. Additionally, we examined the availability of CECT screening for the coelomic organs. Different doses of iopamidol (100, 300, 500, and 700 mg iodine [mgI]/kg) were administered intravenously for 20 s in six sharks. The CT scans from the pectoral girdle to the pelvic girdle were performed at 0-600 s after administration. Contrast-enhanced CT imaging of the CAs, gills, and coelomic organs was examined. Assessment of the signal enhancement value revealed that the PCV was easily visualized with all contrast doses at 25 s. The CAs, gills, and DA were visible at a slightly higher dose (CAs and gills: 200 mgI/kg at 40 s; DA: 300 mgI/kg at 50 s). The HPV was obvious at a dose of at least 500 mgI/kg after a 150-s delay. The parenchyma of the kidney had a contrast effect at 300 mgI/kg, 150 s after the contrast effect of the renal portal system disappeared. The liver, which stores a lot of lipids, had poor overall contrast enhancement that was optimized at the highest dose of 700 mgI/kg. Contrast-enhanced CT screening at 700 mgI/kg and 150 s is likely to obtain the optimal imaging of the reproductive organs, such as the ovary, oviducal gland, uterus, and testis. The present findings can be applied not only to clinical practice but also to academic research and education on elasmobranchs in aquariums.

INTRAVENOUS IOPAMIDOL PHARMACOKINETICS IN COMMON CARP (CYPRINUS CARPIO).

Koi carp (Cyprinus carpio), a variety of common carp, has gained popularity as an ornamental fish worldwide. Their high monetary and sentimental value has necessitated the development of antemortem diagnostic options. Contrast-enhanced computed tomography (CT) scanning with intravenous iopamidol has been shown to be safe and diagnostically effective at a minimum dose of 480 mg iodine (I)/kg in koi. The purpose of this study was to evaluate the pharmacokinetic parameters of this dose of iopamidol, as well as excretory mechanisms specific to fish, using common carp as a model. Blood, posterior kidney, gill, and bile were collected, necessitating sacrificial sampling. Thirty-five adult fish were randomly divided into six sampling groups. Five sampling groups (n = 6/group) received 480 mg I/kg; the control group (n = 5) received an equivalent volume of saline. The iopamidol groups were sampled at the following time points postinjection: 5 min, 1 hr, 6 hr, 24 hr, and 48 hr. The control group was sampled at 48 hr. Concentrations of iopamidol were determined using liquid chromatography tandem mass spectrometry; noncompartmental analysis was used to calculate pharmacokinetic parameters. Total clearance (3.04 ml/hr per kilogram) was slower, the volume of distribution smaller (79.92 ml/ kg), and the elimination half-life (20.39 hr) prolonged compared to similar studies in mammals. The time-concentration profiles of kidney and gill were similar; these organs appear to be responsible for the majority of iopamidol excretion. However, that of bile was much different, showing slower, low-level accumulation with time, suggesting that in fish, multiple organ systems play a role in elimination beyond just the kidney. In particular, they may rely more heavily upon biliary excretion, which thus far has been noted only in mammals with renal impairment. Further research is warranted to investigate if the slower elimination allows diagnostic CT images to be acquired at different time points postinjection.