Cushioned-Density Gradient Ultracentrifugation (C-DGUC) improves the isolation efficiency of extracellular vesicles

Ultracentrifugation (UC) is recognized as a robust approach for the isolation of extracellular vesicles (EVs). However, recent studies have highlighted limitations of UC including low recovery efficiencies and aggregation of EVs that could impact downstream functional analyses. We tested the benefit of using a liquid cushion of iodixanol during UC to address such shortcomings. In this study, we compared the yield and purity of EVs isolated from J774A.1 macrophage conditioned media by conventional UC and cushioned-UC (C-UC). We extended our study to include two other common EV isolation approaches: ultrafiltration (UF) and polyethylene glycol (PEG) sedimentation. After concentrating EVs using these four methods, the concentrates underwent further purification by using OptiPrep density gradient ultracentrifugation (DGUC). Our data show that C-DGUC provides a two-fold improvement in EV recovery over conventional UC-DGUC. We also found that UF-DGUC retained ten-fold more protein while PEG-DGUC achieved similar performance in nanoparticle and protein recovery compared to C-DGUC. Regarding purity as assessed by nanoparticle to protein ratio, our data show that EVs isolated by UC-DGUC achieved the highest purity while C-DGUC and PEG-DGUC led to similarly pure preparations. Collectively, we demonstrate that the use of a high-density iodixanol cushion during the initial concentration step improves the yield of EVs derived from cell culture media compared to conventional UC. This enhanced yield without substantial retention of protein contaminants and without exposure to forces causing aggregation offers new opportunities for the isolation of EVs that can subsequently be used for functional studies.

Iodine Quantification Using Dual-Energy Computed Tomography for Differentiating Thymic Tumors

The aim of the study was to explore the efficacy of iodine quantification with dual-energy computed tomography (DECT) in differentiating thymoma, thymic carcinoma, and thymic lymphoma.

MATERIALS AND METHODS

Fifty-seven patients with pathologically confirmed low-risk thymoma (n = 16), high-risk thymoma (n = 15), thymic carcinoma (n = 14), and thymic lymphoma (n = 12) underwent chest contrast-enhanced DECT scan were enrolled in this study. Tumor DECT parameters including iodine-related Hounsfield unit (IHU), iodine concentration (IC), mixed HU (MHU), and iodine ratio in dual phase, slope of energy spectral HU curve (λ), and virtual noncontrast (VNC) were compared for differences among 4 groups by one-way analysis of variance. Receiver operating characteristic curve was used to determine the efficacy for differentiating the low-risk thymoma from other thymic tumor by defined parameters.

RESULTS

According to quantitative analysis, dual-phase IHU, IC, and MHU values in patients with low-risk thymoma were significantly increased compared with patients with high-risk thymoma, thymic carcinoma, and thymic lymphoma (P < 0.05/4).The venous phase IHU value yielded the highest performance with area under the curve of 0.893, 75.0% sensitivity, and 89.7% specificity for differentiating the low-risk thymomas from high-risk thymomas or thymic carcinoma at the cutoff value of 34.3 HU. When differentiating low-risk thymomas from thymic lymphoma, the venous phase IC value obtained the highest diagnostic efficacy with the area under the curve of 0.969, and sensitivity, specificity, and cutoff value were 87.5%, 100.0%, and 1.25 mg/mL, respectively.

CONCLUSIONS

Iodine quantification with DECT may be useful for differentiating the low-risk thymomas from other thymic tumors.

Image quality in coronary computed tomography angiography: influence of adaptive statistical iterative reconstruction at various radiation dose levels

Background Computed tomography (CT) technology is rapidly evolving and software solution developed to optimize image quality and/or lower radiation dose. Purpose To investigate the influence of adaptive statistical iterative reconstruction (ASIR) at different radiation doses in coronary CT angiography (CCTA) in detailed image quality. Material and Methods A total of 160 CCTA were reconstructed as follows: 55 scans with filtered back projection (FBP) (650 mA), 51 scans (455 mA) with 30% ASIR (ASIR30), and 54 scans (295 mA) with 60% ASIR (ASIR60). For each reconstruction, subjective image quality was assessed by five independent certified cardiologists using a visual grading analysis (VGA) with five predefined image quality criteria consisting of a 5-point scale. Objective measures were contrast, noise, and contrast-to-noise ratio (CNR). Results The CTDI_vol resulted in 10.3 mGy, 7.4 mGy, and 4.6 mGy for FBP, ASIR30, and ASIR60, respectively. Homogeneity of the left ventricular lumen was the sole aspect in which reconstruction algorithms differed with a decreasing effect for ASIR60 compared to FBP (estimated odds ratio [OR] = 0.49 [95% confidence interval (CI) = 0.32-0.76; P = 0.001]). Decreased sharpness and spatial- and low-contrast resolutions were observed when using ASIR instead of FBP, but differences were not statistically significant. Concerning objective measurements, noise increased significantly for ASIR30 (OR = 1.08; 95% CI = 1.02-1.14; P = 0.006) and ASIR60 (OR = 1.06; 95% CI = 1.01-1.12; P = 0.034) compared to FBP. Conclusion ASIR significantly decreased the subjectively assessed homogeneity of the left ventricular lumen and increased the objectively measured noise compared to FBP. Considering these results, ASIR at a reduced radiation dose should be implemented with caution.

Selection Strategies for Atlas-Based Mosaicing of Left Atrial 3-D Transesophageal Echocardiography Data

Three-dimensional transesophageal echocardiography (TEE) provides real-time soft tissue information, but its use is hampered by its limited field of view. The mosaicing of multiple TEE views makes it possible to visualize a large structure, like the left atrium, in a single volume. To this end, an automatic registration method is required. Similarly to atlas-based segmentation approaches, atlas-based mosaicing (ABM) uses a full volume atlas set to moderate the onerous registration of the individual TEE views. The performance of ABM depends both on the quality of the involved registrations and on the selection of the optimal transformation from the candidate transformations that result from the various atlases. The study described here explored the performance of different selection strategies on multiview TEE data of the left atrium. We found that by incorporating two stages of transformation selection, using the image similarity and the conformity between the candidate transformations as selection criteria, the average registration error dropped below 3 mm with respect to manual registration of these data. Finally, we used this method for the automatic construction of a wide-view TEE volume of the left atrium.

The combination of a reduction in contrast agent dose with low tube voltage and an adaptive statistical iterative reconstruction algorithm in CT enterography: Effects on image quality and radiation dose

To investigate the subjective and quantitative image quality and radiation exposure of CT enterography (CTE) examination performed at low tube voltage and low concentration of contrast agent with adaptive statistical iterative reconstruction (ASIR) algorithm, compared with conventional CTE.One hundred thirty-seven patients with suspected or proved gastrointestinal diseases underwent contrast enhanced CTE in a multidetector computed tomography (MDCT) scanner. All cases were assigned to 2 groups. Group A (n = 79) underwent CT with low tube voltage based on patient body mass index (BMI) (BMI < 23 kg/m, 80 kVp; BMI ≥ 23 kg/m, 100 kVp) and low concentration of contrast agent (270 mg I/mL), the images were reconstructed with standard filtered back projection (FBP) algorithm and 50% ASIR algorithm. Group B (n = 58) underwent conventional CTE with 120 kVp and 350 mg I/mL contrast agent, the images were reconstructed with FBP algorithm. The computed tomography dose index volume (CTDIvol), dose length product (DLP), effective dose (ED), and total iodine dosage were calculated and compared. The CT values, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) of the normal bowel wall, gastrointestinal lesions, and mesenteric vessels were assessed and compared. The subjective image quality was assessed independently and blindly by 2 radiologists using a 5-point Likert scale.The differences of values for CTDIvol (8.64 ± 2.72 vs 11.55 ± 3.95, P < .001), ED (6.34 ± 2.24 vs 8.52 ± 3.02, P < .001), and DLP (422.6 ± 149.40 vs 568.30 ± 213.90, P < .001) were significant between group A and group B, with a reduction of 25.2%, 25.7%, and 25.7% in group A, respectively. The total iodine dosage in group A was reduced by 26.1%. The subjective image quality did not differ between the 2 groups (P > .05) and all image quality scores were greater than or equal to 3 (moderate). Fifty percent ASIR-A group images provided lower image noise, but similar or higher quantitative image quality in comparison with FBP-B group images.Compared with the conventional protocol, CTE performed at low tube voltage, low concentration of contrast agent with 50% ASIR algorithm produce a diagnostically acceptable image quality with a mean ED of 6.34 mSv and a total iodine dose reduction of 26.1%.

Flip-angle based ratiometric approach for pulsed CEST-MRI pH imaging

Several molecules have been exploited for developing MRI pH sensors based on the chemical exchange saturation transfer (CEST) technique. A ratiometric approach, based on the saturation of two exchanging pools at the same saturation power, or by varying the saturation power levels on the same pool, is usually needed to rule out the concentration term from the pH measurement. However, all these methods have been demonstrated by using a continuous wave saturation scheme that limits its translation to clinical scanners. This study shows a new ratiometric CEST-MRI pH-mapping approach based on a pulsed CEST saturation scheme for a radiographic contrast agent (iodixanol) possessing a single chemical exchange site. This approach is based on the ratio of the CEST contrast effects at two different flip angles combinations (180°/360° and 180°/720°), keeping constant the mean irradiation RF power (B_{avg power}). The proposed ratiometric approach index is concentration independent and it showed good pH sensitivity and accuracy in the physiological range between 6.0 and 7.4.

Utility of (18) F-FDG PET/CT and CECT in conjunction with serum CA 19-9 for detecting recurrent pancreatic adenocarcinoma

PURPOSE

The roles of different cross-sectional imaging in evaluating the recurrence of pancreatic adenocarcinoma are not well established. We evaluated the utility of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) and contrast-enhanced computed tomography (CECT) in the diagnosis of recurrent pancreatic adenocarcinoma in conjunction with the tumor marker CA 19-9.

METHODS

We retrospectively reviewed the records of patients who underwent CECT and FDG PET/CT along with serum CA 19-9 measurement as a follow-up or on a clinical suspicion of recurrent disease after initial surgery for pancreatic adenocarcinoma. Two observers blinded to the other imaging modality results retrospectively reviewed and interpreted the images in consensus using a three-point scale (negative, equivocal, or positive). Pathologic analysis by biopsy or further clinical and radiologic follow-up determined the true status of the suspected recurrences. The imaging results were compared with CA 19-9 levels and true disease status.

RESULTS

Thirty-nine patients were included in the study. Thirty-three patients (85%) had proven recurrent cancer and six patients (15%) had no evidence of disease. Twenty-four patients had elevated CA 19-9 and 15 patients had normal CA 19-9. Sensitivity, specificity, and accuracy for recurrence were 90.9%, 100.0%, and 92.3% for PET/CT and 72.2%, 66.6%, and 71.7% for CECT, respectively. Sensitivity for locoregional recurrence was 94.4% for PET/CT but only 61.1% for CECT. PET/CT detected recurrence in 12 patients who had normal levels of CA 19-9. PET/CT showed lesions not visible on CECT in five (15%) patients. Although the sensitivity and specificity of PET/CT were higher than those of CECT, they were not statistically significant (p = 0.489 and p = 0.1489, respectively).

CONCLUSION

FDG PET/CT has a high sensitivity for pancreatic cancer recurrence. Normal CA 19-9 does not necessarily exclude these recurrences. FDG PET/CT is useful when CECT is equivocal and can detect recurrence in patients with normal CA 19-9.

Augmented-pressure distal colostogram: the most important diagnostic tool for planning definitive surgical repair of anorectal malformations in boys

There is little current literature on the augmented-pressure distal colostogram, the single most important diagnostic study performed in boys with imperforate anus prior to definitive repair. Accurate understanding of the anatomy of the anorectal malformation including an associated fistulous communication between the rectum and the urogenital tract is essential for optimal surgical management. Specifically, the position of the rectal pouch and recto-urinary fistula relative to posterior sagittal structures of the perineum, especially the sacral spine, dictates the operative approach. This pictorial essay is a guide for those who encounter such children with relative infrequency to become more comfortable with the technique. We report how to perform this radiologic exam and the potential pitfalls from our experience of performing the technique in our large pediatric colorectal practice.

Hydrothorax, ascites and an abdominal mass: not always signs of a malignancy - Three cases of Meigs' syndrome

This case report presents three cases of Meigs' syndrome: a benign ovarian tumor with ascites and a hydrothorax. After removal of the ovarian tumor, the symptoms resolved and the patients became asymptomatic. In daily practice, Meigs' syndrome is at first sight often mistaken for ovarian cancer. With this case report we would like to emphasize that the clinical presentation of an ovarian tumor might be ovarian cancer, but can masquerade as something uncommon like Meigs' syndrome. In a time span of two years we encountered three cases.

Diagnostic Accuracy of Noninvasive 64-row Computed Tomographic Coronary Angiography (CCTA) Compared with Myocardial Perfusion Imaging (MPI): The PICTURE Study, A Prospective Multicenter Trial

RATIONALE AND OBJECTIVES

Although multiple studies have shown excellent accuracy statistics for noninvasive angiography by coronary computed tomographic angiography (CCTA), most studies comparing nuclear imaging to CCTA were performed on patients already referred for cardiac catheterization, introducing referral and selection bias. This prospective trial evaluated the diagnostic accuracy of 64-row CCTA to detect obstructive coronary stenosis compared to myocardial perfusion imaging (MPI), using quantitative coronary angiography (QCA) as a reference standard.

MATERIALS AND METHODS

Twelve sites prospectively enrolled 230 patients (49% male, 57.8 years) with chest pain. All patients underwent MPI and CCTA (Lightspeed VCT/Visipaque 320, GE Healthcare, Milwaukee, WI, USA) prior to invasive coronary angiography (ICA). All patients were evaluated, and those found to have either an abnormal MPI or CCTA were clinically referred for ICA. CCTAs were graded on a 15-segment American Heart Association model by three blinded readers for presence of obstructive stenosis (>50% or >70%); MPI was graded by two blinded readers using a 17-segment model for estimation of the % myocardium ischemic or with stress defects. ICAs were independently graded for % stenosis by QCA. The efficacies of MPI and CCTA were assessed including all vessel segments for per-patient and per-vessel analyses.

RESULTS

The prevalence of stenosis ≥50% by ICA was 52.1% (25 of 48). The sensitivity of CCTA was significantly higher than nuclear imaging (92.0% vs 54.5%, P < 0.001), with similar specificity (87.0% vs 78.3%) when obstructive disease was defined as ≥50%. CCTA provided superior sensitivity (92.6% vs 59.3%, P < 0.001) and similar specificity (88.9% vs 81.5%) using QCA stenosis ≥70%. For ≥50% stenosis, the computed tomographic angiography odds ratio for ICA disease was 51.75 (95% CI = 8.50-314.94, P < 0.001). For summed stress score ≥5%, the odds ratio for ICA CAD was 12.73 (95% CI = 2.43-66.55, P < 0.001). Using receiver operating characteristic curve analysis, CCTA was better at classifying obstructive coronary artery disease when compared to MPI (area = 0.85 vs 0.71, P < 0.0001).

CONCLUSIONS

This study represents one of the first prospective multicenter, controlled clinical trials comparing 64-row CCTA to MPI in the same patients, demonstrating superior diagnostic accuracy of CCTA over myocardial perfusion single photon emission computed tomography (MPS) to reliably detect >50% and >70% stenosis in stable chest pain patients.

Currarino Syndrome and the Effect of a Large Anterior Sacral Meningocele on Distal Colostogram in an Anorectal Malformation

Currarino syndrome is a congenital disorder, consisting of a triad of anomalies including an anorectal malformation, sacral anomaly, and a presacral mass. Anterior sacral meningoceles are the most common presacral mass. A young child presented to our institution with an unrepaired anorectal malformation and a large anterior sacral meningocele. We describe how the anterior meningocele affected the imaging work-up.

Trichoderma asperellum Induces Maize Seedling Growth by Activating the Plasma Membrane H+-ATPase

Although Trichoderma spp. have beneficial effects on numerous plants, there is not enough knowledge about the mechanism by which they improves plant growth. In this study, we evaluated the participation of plasma membrane (PM) H⁺-ATPase, a key enzyme involved in promoting cell growth, in the elongation induced by T. asperellum and compared it with the effect of 10 μM indol acetic acid (IAA) because IAA promotes elongation and PM H⁺-ATPase activation. Two seed treatments were tested: biopriming and noncontact. In neither were the tissues colonized by T. asperellum; however, the seedlings were longer than the control seedlings, which also accumulated IAA and increased root acidification. An auxin transport inhibitor (2,3,5 triiodobenzoic acid) reduced the plant elongation induced by Trichoderma spp. T. asperellum seed treatment increased the PM H⁺-ATPase activity in plant roots and shoots. Additionally, the T. asperellum extracellular extract (TE) activated the PM H⁺-ATPase activity of microsomal fractions of control plants, although it contained 0.3 μM IAA. Furthermore, the mechanism of activation of PM H⁺-ATPase was different for IAA and TE; in the latter, the activation depends on the phosphorylation state of the enzyme, suggesting that, in addition to IAA, T. asperellum excretes other molecules that stimulate PM H⁺-ATPase to induce plant growth.

Use of C-Arm Cone Beam CT During Hepatic Radioembolization: Protocol Optimization for Extrahepatic Shunting and Parenchymal Enhancement

PURPOSE

To optimize a C-arm computed tomography (CT) protocol for radioembolization (RE), specifically for extrahepatic shunting and parenchymal enhancement.

MATERIALS AND METHODS

A prospective development study was performed per IDEAL recommendations. A literature-based protocol was applied in patients with unresectable and chemorefractory liver malignancies undergoing an angiography before radioembolization. Contrast and scan settings were adjusted stepwise and repeatedly reviewed in a consensus meeting. Afterwards, two independent raters analyzed all scans. A third rater evaluated the SPECT/CT scans as a reference standard for extrahepatic shunting and lack of target segment perfusion.

RESULTS

Fifty scans were obtained in 29 procedures. The first protocol, using a 6 s delay and 10 s scan, showed insufficient parenchymal enhancement. In the second protocol, the delay was determined by timing parenchymal enhancement on DSA power injection (median 8 s, range 4-10 s): enhancement improved, but breathing artifacts increased (from 0 to 27 %). Since the third protocol with a 5 s scan decremented subjective image quality, the second protocol was deemed optimal. Median CNR (range) was 1.7 (0.6-3.2), 2.2 (-1.4-4.0), and 2.1 (-0.3-3.0) for protocol 1, 2, and 3 (p = 0.80). Delineation of perfused segments was possible in 57, 73, and 44 % of scans (p = 0.13). In all C-arm CTs combined, the negative predictive value was 95 % for extrahepatic shunting and 83 % for lack of target segment perfusion.

CONCLUSION

An optimized C-arm CT protocol was developed that can be used to detect extrahepatic shunts and non-perfusion of target segments during RE.

Effect of Temperature-Sensitive Poloxamer Solution/Gel Material on Pericardial Adhesion Prevention: Supine Rabbit Model Study Mimicking Cardiac Surgery

Objective

We investigated the mobility of a temperature-sensitive poloxamer/Alginate/CaCl₂ mixture (PACM) in relation to gravity and cardiac motion and the efficacy of PACM on the prevention of pericardial adhesion in a supine rabbit model.

Methods

A total of 50 rabbits were randomly divided into two groups according to materials applied after epicardial abrasion: PACM and dye mixture (group PD; n = 25) and saline as the control group (group CO; n = 25). In group PD, rabbits were maintained in a supine position with appropriate sedation, and location of mixture of PACM and dye was assessed by CT scan at the immediate postoperative period and 12 hours after surgery. The grade of adhesions was evaluated macroscopically and microscopically two weeks after surgery.

Results

In group PD, enhancement was localized in the anterior pericardial space, where PACM and dye mixture was applied, on immediate post-surgical CT scans. However, the volume of the enhancement was significantly decreased at the anterior pericardial space 12 hours later (P < .001). Two weeks after surgery, group PD had significantly lower macroscopic adhesion score (P = .002) and fibrosis score (P = .018) than did group CO. Inflammation score and expression of anti-macrophage antibody in group PD were lower than those in group CO, although the differences were not significant.

Conclusions

In a supine rabbit model study, the anti-adhesion effect was maintained at the area of PACM application, although PACM shifted with gravity and heart motion. For more potent pericardial adhesion prevention, further research and development on the maintenance of anti-adhesion material position are required.

Evaluation of urine fibrinogen level in a murine model of contrast-induced nephropathy

OBJECTIVE

The mechanisms of contrast-induced nephropathy are not fully understood and sensitive biomarkers of contrast-induced nephropathy are yet to be found. We investigated whether urinary fibrinogen could be a potential biomarker for contrast-induced nephropathy.

METHODS

To create a contrast-induced nephropathy model, mice received a prostaglandin synthesis inhibitor (indomethacin) and a nitric oxide synthase inhibitor (Nω-Nitro-L-arginine methyl ester) intraperitoneally followed by a different dose of iodixanol. In the control group, normal saline was administered. Urinary fibrinogen and serum creatinine were analyzed using enzyme-linked immunosorbent assay. Kidneys were used to quantify fibrinogen using qRT-PCR and Western blot and for histopathological examination.

RESULTS

Histopathological examination demonstrated mild renal injury in the low-dose group, and moderate renal injury in the high-dose group. Urinary fibrinogen levels were significantly increased in an iodixanol dose-dependent manner (control vs. low-dose group, P < 0.05; control vs. high-dose group P < 0.01). Serum creatinine levels were only increased in the high-dose group (P < 0.01 compared to control), but not in the low-dose group. For fibrinogen-gene expression, in the low-dose group, Fgγ increased (qRT-PCR, Western blot, P < 0.05) in the high-dose group, Fgβ and Fgγ decreased (qRT-PCR, P < 0.01; Western blot, P < 0.05), and Fgα increased (qRT-PCR, P < 0.05; Western blot, P < 0.05).

CONCLUSIONS

We propose that urinary fibrinogen could be used as a potential biomarker for early contrast-induced nephropathy diagnosis.

[Application feasibility of low tube voltage and lower iodine concentration contrast medium as well as iterative reconstruction in coronary computed tomography angiography]

OBJECTIVE

To investigate the feasibility of using lower iodine concentration (270 mgI/ml) contrast medium, lower X-ray tube voltage (100 kVp) and iterative reconstruction (IR) to reduce both iodine load and radiation dose but keep the image quality of coronary CT angiography (CCTA).

METHODS

A total of 80 consecutive patients with suspected coronary artery disease were prospectively assigned to one of two groups via computer central system from January to May 2013. The control group (n = 40) was scanned using dual-source CCTA protocols of 120 kV, 370 mgI/ml Iopromide and filtered back projection reconstruction with a vascular algorithm (B26f). The study group (n = 40) was scanned using 100 kV, 270 mgI/ml Iodixanol and sinogram affirmed iterative reconstruction with a vascular algorithm (I26f). Other scan parameters and contrast injection protocol were similar between the two groups. Attenuation in the ascending aorta and coronary arteries along with image noise were measured. Images were reconstructed, measured and graded, and iodine load and effective radiation dose were calculated.

RESULTS

The body mass index ((25.3 ± 3.0) kg/m² vs. (25.4 ± 3.0)kg/m², P = 0.852), image quality scores (4.70 ± 0.52 vs. 4.63 ± 0.59, P = 0.545), mean signal-to-noise ratios (22.2 ± 5.5 vs. 23.6 ± 5.8, P = 0.277), and contrast-to-noise ratios (35.6 ± 17.6 vs. 41.1 ± 17.6, P = 0.163) were similar between the control group and study group. Mean iodine loads were significantly reduced in the study group ((18.49 ± 0.75)g) compared to control group ((25.27 ± 0.94)g), P< 0.001). Mean effective radiation doses were also significantly reduced in the study group ((2.31 ± 0.73) mSv) compared to that in control group ((3.52 ± 1.16) mSv), P< 0.001).

CONCLUSION

Use of low X-ray tube voltage and iterative reconstruction allows lower iodine load and effective radiation dose application at CCTA without image quality reduction.

The potential utility of iodinated contrast media (ICM) skin testing in patients with ICM hypersensitivity

Both immediate and delayed hypersensitivity reactions to iodinated contrast media (ICM) are relatively common. However, there are few data to determine the clinical utility of immunologic evaluation of ICM. To evaluate the utility of ICM skin testing in patients with ICM hypersensitivity, 23 patients (17 immediate and 6 delayed reactions) were enrolled from 3 university hospitals in Korea. With 6 commonly used ICM including iopromide, iohexol, ioversol, iomeprol, iopamidol and iodixanol, skin prick (SPT), intradermal (IDT) and patch tests were performed. Of 10 patients with anaphylaxis, 3 (30.0%) and 6 (60.0%) were positive respectively on SPTs and IDTs with the culprit ICM. Three of 6 patients with urticaria showed positive IDTs. In total, 11 (64.7%) had positive on either SPT or IDT. Three of 6 patients with delayed rashes had positive response to patch test and/or delayed IDT. Among 5 patients (3 anaphylaxis, 1 urticaria and 1 delayed rash) taken subsequent radiological examinations, 3 patients administered safe alternatives according to the results of skin testing had no adverse reaction. However, anaphylaxis developed in the other 2 patients administered the culprit ICM again. With 64.7% (11/17) and 50% (3/6) of the sensitivities of corresponding allergic skin tests with culprit ICM for immediate and delayed hypersensitivity reactions, the present study suggests that skin tests is useful for the diagnosis of ICM hypersensitivity and for selecting safe ICM and preventing a recurrence of anaphylaxis caused by the same ICM.

Transbrachial approach to the treatment of uterine leiomyomas with embolization of the uterine arteries: a preliminary technical experience

INTRODUCTION

Uterine leiomyomas are benign tumours; recently they have been managed with embolization of the uterine arteries. We analysed the technical feasibility, safety and efficacy of this treatment performed via an innovative transbrachial approach, rather than the traditional transfemoral approach.

MATERIALS AND METHODS

Between 2009 and 2013, 115 patients were treated with embolization of the uterine arteries for one or more symptomatic leiomyomas. In 20 of these 115 patients, a transbrachial approach was used. Under ultrasound guidance, the left brachial artery was punctured. After having placed the tip of the angiography catheter at the level of L4 to check the aortic bifurcation, the uterine arteries were catheterised and embolized with calibrated particles. Data concerning exposure to radiation and the duration of the intervention were recorded for comparison between the two groups of subjects. Clinical controls and magnetic resonance imaging were complemented with echo-colour Doppler of the brachial artery to confirm the integrity and function of the vessel.

RESULTS

The uterine arteries were catheterised easily in a mean time of 25″, compared to 72″ using the femoral approach. As far as exposure to radiation was concerned, the mean fluoroscopy time for the femoral approach was 21.7' [range 14.4-42.7'] compared to 17.6' [range 7.7-25.5'] for the transbrachial approach. The time of occupation of the angiography suite was 118' (range 95-155') with the femoral approach, compared to 92' (range 65-123') with the transbrachial approach. No immediate complications involving the brachial artery were recorded.

DISCUSSION

In the treatment of symptomatic uterine fibromas, embolization of the uterine arteries performed via a transbrachial approach was shown to be safe and technically valid with regard to reducing the overall time of the intervention, ease of selective catheterisation, and shorter times spent in hospital, as well as being better accepted by patients.

CT texture analysis of renal masses: pilot study using random forest classification for prediction of pathology

RATIONALE AND OBJECTIVES

Computed tomography texture analysis (CTTA) allows quantification of heterogeneity within a region of interest. This study investigates the possibility of distinguishing between several common renal masses using CTTA-derived parameters by developing and validating a predictive model.

MATERIALS AND METHODS

CTTA software was used to analyze 20 clear cell renal cell carcinomas (RCCs), 20 papillary RCCs, 20 oncocytomas, and 20 renal cysts. Regions of interest were drawn around each mass on multiple slices in the arterial, venous, and delayed phases on renal mass protocol CT scans. Unfiltered images and spatial band-pass filtered images were analyzed to quantify heterogeneity. Random forest method was used to construct a predictive model to classify lesions using quantitative parameters. The model was externally validated on a separate set of 19 unknown cases.

RESULTS

The random forest model correctly categorized oncocytomas in 89% of cases (sensitivity = 89%, specificity = 99%), clear cell RCCs in 91% of cases (sensitivity = 91%, specificity = 97%), cysts in 100% of cases (sensitivity = 100%, specificity = 100%), and papillary RCCs in 100% of cases (sensitivity = 100%, specificity = 98%).

CONCLUSIONS

CTTA, in conjunction with random forest modeling, demonstrates promise as a tool to characterize lesions. Various renal masses were accurately classified using quantitative information derived from routine scans.

[Preliminary study on CT retrograde intubation dacryosystography (CT-RIDC) and its impact factors]

OBJECTIVE

To observe practicality and safety of CT-RIDC for the patients with presaccular lacrimal obstruction and study the related factors. To provide guidance for the diagnosis and treatment of the patients with presaccular lacrimal obstruction.

METHODS

Fifty-four patients (75 eyes) with presaccular lacrimal obstruction, including 3 cases (5 eyes) of upper and lower lacrimal punctum atresia, 15 cases (24 eyes) of superior and inferior canalicular obstruction, 18 cases (28 eyes) of common canaliculus obstruction, 18 cases (18 eyes) of old laceration of superior and inferior canalicular, were recruited. All patients underwent the examination by using 0° and 30° ear endoscope and the imaging characteristics of the inferior orifice of nasolacrimal duct were obtained. Fifty-three cases (65 eyes) with the opening inferior orifice were randomly divided into four groups (15 eyes, 17 eyes, 17 eyes, 16 eyes) according to different angle of head hypsokinesis in the supine position. The OM lines back along the sagittal plane of the head back 10°, 20°, 30°, 40° were measured. The angles of head hypsokinesis were set in accordance with the OM line measurement results.Intubation was successful when the intubation guided needle within the set of epidural anesthetic catheter aided with endoscopy was inserted into the inferior orifice of nasolacrimal duct and then the epidural anesthetic catheter was inserted into the lacrimal duct 6 mm. The angle (θ) between the long axis of the curved part of the intubation guided needle and the long axis of the guided needle was measured. The numbers of intubation success cases in each group were recorded.χ² test was used to compare intubation success rate under the different angle of head hypsokinesis.Scheffe method was used to compare intubation success rate between each group. Contrast medium was then injected into lacrimal duct through the epidural anesthetic catheter for patients with successful intubation and CT scan was carried out. 3D model of lacrimal passage was reconstructed with CT axial scanning.

RESULTS

The intubation guided needle was successfully inserted into the inferior orifice of nasolacrimal duct in 44 eyes among 65 eyes with the opening orifice. The number of successful intubation cases were 4 eyes, 15 eyes, 13 eyes, 12 eyes and the intubation success rate was 26.67%, 88.24%, 76.74%, 75.00% according the angle of head hypsokinesis 10° group (15 eyes), 20° group (17 eyes), 30° group (17 eyes), 40° group (16 eyes). The intubation success rate of head hypsokinesis 10° group was significantly lower than that of the other groups. Multiple Comparison by Scheffe Test demonstrated that there was a remarkable difference (P < 0.05) in the intubation success rate between head hypsokinesis 10° group and the other three groups. There were no significant differences in the intubation success rate among head hypsokinesis 20° group, head hypsokinesis 30° group and head hypsokinesis 40° group. The mean of θ was 108° with a range of 93.2°-120.5° by measuring the angle θ of the successful intubation cases. According to the frequency distribution plot, most θ was in 104°-115°. The successful intubation cases (44 eyes) underwent CT scan in the same position immediately after injected contrast medium (Optiray) through the epidural anesthetic catheter. CT images of 28 eyes showed retained contrast medium in the nasolacrimal duct and lacrimal sac. The findings from CT-DCG images were basically agreed with the operation.

CONCLUSIONS

CD-RIDC may apply to pre-operative examination for the patients with the opening orifice and presaccular lacrimal obstruction.It provideed imaging evidence for diagnosis and therapy and it was safe and practical. Many factors could affect CD-RIDC. The main verified facors were the shape of the inferior orifice of nasolacrimal duct, head position of the patient and the bending angle of the tip of intubation guided needle.

Left atrial function and maximum volume as determined by MDCT are independently associated with atrial fibrillation

RATIONALE AND OBJECTIVES

To assess whether left atrial (LA) volume, function, and diameter as determined by multidetector computed tomography (MDCT) are associated with the presence and chronicity of atrial fibrillation (AF).

MATERIALS AND METHODS

A total of 232 subjects, 156 with AF (43 with chronic and 113 with paroxysmal) and 76 normal subjects, formed the study population. AF subjects underwent MDCT of the pulmonary veins and LA, and normal subjects underwent coronary computed tomography (CT), on which LA volume, function, and diameter were measured. Associations between each MDCT LA parameter and presence and chronicity of AF were assessed using logistic regression analysis.

RESULTS

The indexed LA maximum volume (odds ratio [OR]=2.42; 95% confidence interval [CI], 1.43-4.08; P=.0009) was significantly associated with chronicity and presence of AF (OR=1.06; 95% CI, 1.03-1.10; P=.0003) after adjustment for traditional risk factors. The LA function was associated with presence of AF (OR=0.93; 95% CI, 0.89-0.97; P=.0005), but not with AF chronicity (OR=1.12; 95% CI, 0.93-1.33; P=.21).

CONCLUSIONS

Decreased LA function is associated with presence of AF, and increased LA maximum volume is associated with presence and chronicity of AF, independent of traditional risk factors.

[Low concentration of iodixanol used in CT angiography of lower extremity arteriosclerosis obliterans]

OBJECTIVE

To evaluate the clinical diagnostic value of low concentration of iodixanol used in CT angiography (CTA) of lower extremity arteriosclerosis obliterans (LEASO).

METHODS

42 patients which were suspect diagnosed with LEASO were divided to A group (270 mgI/ml iodixanol, tube voltage 100 kV) and B group (350 mgI/ml iohexol, tube voltage 120 kV), 21 patients in each group. Measure the body mass index (BMI) before the CTA of lower extremity. CTA results were analyzed with the digital subtraction angiography (DSA) as the "gold standard".

RESULTS

There were no statistical difference of age, gender, BMI and CT value of the bifurcation of profunda femoral artery and superficial femoral artery, upper segment of anterior tibial artery and posterior tibial artery between A and B group. The diagnostic sensitivity and specificity of A and B groups of CTA were 97.0%, 99.1% and 98.3%, 99.5% for occlusion. Regard artery more than moderate stenosis (include moderate stenosis) as the overall statistics, the diagnostic sensitivity and specificity of A and B groups of CTA were 99.2%, 99.3% and 99.1%, 99.3%, the accuracy were 92.9% and 93.0%, the positive predictive and negative predictive value were 96.9%, 99.3% and 96.6%, 99.3%, respectively. The kappa value of A and B groups of CTA and DSA consistency test were 0.930 and 0.927, respectively.

CONCLUSION

The CTA with low concentration of iodixanol combine with low tube voltage can achieve superior conventional scanning imaging features, and has great clinical value in the diagnosis of LEASO, also is an effective method for the inspection, evaluation and follow-up.

[Low-concentration contrast material for dual-source computed tomography coronary angiography by a combination of iterative reconstruction and low-tube-voltage technique: feasibility study]

OBJECTIVE

To assess the impact of low concentration contrast media on the degree of vascular enhancement, image quality and radiation dose in coronary CT angiography (cCTA) studies when using a combination of iterative reconstruction and low tube voltage.

METHODS

120 patients who underwent cCTA were randomly divided into two groups. The patients in group A received iopromide 370 were scanned using the conventional tube output, and images were reconstructed using filtered back projection (FBP). The patients in group B received iodixanol 270 were scanned using the low tube output, and images were reconstructed using iterative reconstruction technique (SAFIRE, Siemens Healthcare). CT attenuation was measured in the coronary arteries, great arteries, interventricular septum and left ventricular cavity. Noise, subjective image quality scores and effective radiation dose were compared between the two groups.

RESULTS

There was no significant difference in the mean CT attenuation achieved, image noise and mean image quality score at each anatomic site between iomeprol 270 group and iopromide 370 group. The effective radiation dose were 0.44 ± 0.25 mSv and 0.94 ± 0.42 mSv for iomeprol 270 and iopromide 370 in low weight subgroups, and 1.17 ± 0.30 mSv and 2.37 ± 0.66 mSv in high weight subgroups, respectively, reflecting dose savings of 53.2% (P < 0.01) and 50.6% (P < 0.01), respectively.

CONCLUSION

The results demonstrate that with a combination of iterative reconstruction and a low tube voltage , a low iodine concentration of 270 mgI/ml still improves the contrast enhancement without impairing image quality, as well as significantly lowers effective radiation dose.

Dual-phase CT findings of groove pancreatitis

PURPOSE

Groove pancreatitis is a rare focal form of chronic pancreatitis that occurs in the pancreaticoduodenal groove between the major and minor papillae, duodenum and pancreatic head. Radiologic appearance and clinical presentation can result in suspicion of malignancy rendering pancreaticoduodenectomy inevitable. This study reports dual phase CT findings in a series of 12 patients with pathology proven groove pancreatitis.

MATERIALS AND METHODS

Retrospective review of preoperative CT findings in 12 patients with histologically proven groove pancreatitis after pancreaticoduodenectomy. Size, location, attenuation, presence of mass or cystic components in the pancreas, groove and duodenum, calcifications, duodenal stenosis and ductal changes were recorded. Clinical data, laboratory values, endoscopic ultrasonographic and histopathological findings were collected.

RESULTS

Soft tissue thickening in the groove was seen in all patients. Pancreatic head, groove and duodenum were all involved in 75% patients. A discrete lesion in the pancreatic head was seen in half of the patients, most of which appeared hypodense on both arterial and venous phases. Cystic changes in pancreatic head were seen in 75% patients. Duodenal involvement was seen in 92% patients including wall thickening and cyst formation. The main pancreatic duct was dilated in 7 patients, with an abrupt cut off in 3 and a smooth tapering stricture in 4. Five patients had evidence of chronic pancreatitis with parenchymal calcifications.

CONCLUSION

Presence of mass or soft tissue thickening in the groove with cystic duodenal thickening is highly suggestive of groove pancreatitis. Recognizing common radiological features may help in diagnosis and reduce suspicion of malignancy.

Impact of contrast agent viscosity on coronary balloon deflation times: bench testing results

OBJECTIVES

To assess the impact of viscosity on angioplasty balloon deflation times.

BACKGROUND

Lower contrast viscosity could result in more rapid coronary balloon deflation times.

METHODS

We performed a bench comparison of coronary balloon deflation times using 2 contrast agents with different viscosity (ioxaglate and iodixanol), 3 contrast dilutions, and 2 inflation syringe filling volumes. Ten identical pairs of coronary angioplasty balloons were used to conduct each comparison after balloon inflation to 12 atmospheres. Simultaneous deflations were performed under cineangiography. The time to full contrast extraction and the area of contrast remaining after 5 seconds of deflation (quantified by opaque pixel count) were compared between groups.

RESULTS

The mean time to full contrast extraction during balloon deflation was 8.3 ± 2.5 seconds for ioxaglate (lower viscosity) versus 10.1 ± 2.9 seconds for iodixanol (higher viscosity) (17.4% decrease, P = 0.005), with a 35.6% (P = 0.004) reduction in contrast area at 5 seconds. Compared to 1:1 ioxaglate-saline mixture, 1:2 and 1:3 ioxaglate/saline mixes resulted in 26.7% (P < 0.001) and 39.0% (P < 0.001) reduction in mean balloon deflation time, respectively, but at the expense of decreased balloon opacity. Filling the inflation syringe with 5 versus 15 ml of contrast/saline solution was associated with 7.5% decrease in balloon deflation time (P = 0.005), but no difference in contrast area at 5 seconds (P = 0.749).

CONCLUSIONS

Use of a lower viscosity contrast agent and higher contrast dilution significantly reduced coronary balloon deflation times, whereas use of lower syringe filling volume had a modest effect. Rapid coronary balloon deflation could improve the safety of interventional procedures.