Radiocontrast medium induces histamine release in association with upregulation of miR‑19a‑3p and miR‑362‑3p expression

In Taiwan, the use of radiocontrast medium for clinical image diagnosis recently surpassed one million times and the overall prevalence of radiocontrast hypersensitivity was ~7%. A microRNA (miRNA/miRs) is a small non-coding RNA molecule that mostly plays a suppressor role in cells. However, the roles of miRNA expression in radiocontrast-induced mast cells activation remains to be elucidated. The aim of the present study was to investigate the role of miRNA on radiocontrast-induced mast cell activation. Computed tomography radiocontrast, ultravist and mouse mast cell line, P815, were used in the present study. Cell viability was detected by CCK-8 experiment. Levels of histamine and β-hexosaminidase were measured by ELISA. miRNA expression was detected by miRNA sequencing and reverse transcription-quantitative PCR. The results showed that ultravist could increase histamine release and reduce intracellular β-hexosaminidase levels of mast cells. A total of 102 miRNAs could be significantly upregulated by ultravist stimulation. Selected candidate miRNAs for the validation included miR-19a-3p and miR-362-3p which were also increased expression following stimulation with ultravist. In conclusion, ultravist could induce mast cell activation through upregulation of miR-19a-3p and miR-362-3p. Thus, miR-19a-3p and miR-362-3p could be promising candidates for development as novel targets for preventing radiocontrast-induced allergy in the future.

Long-term effects of iopamidol as a contrast medium for computed tomography in Cloudy Catsharks Scyliorhinus torazame

OBJECTIVE

The use of computed tomography (CT) in aquarium animals, including elasmobranchs, has increased dramatically. To take advantage of CT, contrast medium is used to enhance internal organs and provide contrast since elasmobranchs lack visceral fat. In this study, the contrast effects of iopamidol were examined for up to 260 days after intravenous administration to establish the time course of the CT values for the target organs in eight mature Cloudy Catsharks Scyliorhinus torazame.

METHODS

A micro-CT system was used to measure the CT values of the designated region of interest in the target organs (ventricular cavity, kidneys, liver, gallbladder, ovarian follicles, uterine horn cavity) over time and the eggs laid, following administration of iopamidol (700 mg of iodine/kg).

RESULT

The CT values of the ventricular cavity and kidneys peaked at 30 min and showed low values after day 22. The CT values for the liver increased over time and peaked at day 200, whereas values for the gallbladder and ovarian follicles peaked on day 6, with the gallbladder showing a low value and the ovarian follicles still showing a high value on day 260. Computed tomography images with identifiable enhancement within bilateral uterine horns were followed from days 1 to 35. The mean and maximum CT values of yolk and jelly in eggs laid after day 30 were significantly higher than the values for eggs laid up to day 29; embryonic development was confirmed in 88.7% of the eggs.

CONCLUSION

There was no mortality or morbidity of the sharks during the experiment, indicating that the administration of iopamidol at 700 mg of iodine/kg did not result in any adverse effects for 260 days. This is the first study to describe the long-term contrast effects of iopamidol, thus contributing new information about the application of contrast studies in Cloudy Catsharks.

Safe and Informed Use of Gadolinium-Based Contrast Agent in Body Magnetic Resonance Imaging: Where We Were and Where We Are

Gadolinium-based contrast agents (GBCAs) have helped to improve the role of magnetic resonance imaging (MRI) for the diagnosis and treatment of diseases. There are currently nine different commercially available gadolinium-based contrast agents (GBCAs) that can be used for body MRI cases, and which are classifiable according to their structures (cyclic or linear) or biodistribution (extracellular-space agents, target/specific-agents, and blood-pool agents). The aim of this review is to illustrate the commercially available MRI contrast agents, their effect on imaging, and adverse reaction on the body, with the goal to lead to their proper selection in different clinical contexts. When we have to choose between the different GBCAs, we have to consider several factors: (1) safety and clinical impact; (2) biodistribution and diagnostic application; (3) higher relaxivity and better lesion detection; (4) higher stability and lower tissue deposit; (5) gadolinium dose/concentration and lower volume injection; (6) pulse sequences and protocol optimization; (7) higher contrast-to-noise ratio at 3.0 T than at 1.5 T. Knowing the patient's clinical information, the relevant GBCAs properties and their effect on body MRI sequences are the key features to perform efficient and high-quality MRI examination.

Optimal Protocol for Contrast-enhanced Free-running 5D Whole-heart Coronary MR Angiography at 3T

Free-running 5D whole-heart coronary MR angiography (MRA) is gaining in popularity because it reduces scanning complexity by removing the need for specific slice orientations, respiratory gating, or cardiac triggering. At 3T, a gradient echo (GRE) sequence is preferred in combination with contrast injection. However, neither the injection scheme of the gadolinium (Gd) contrast medium, the choice of the RF excitation angle, nor the dedicated image reconstruction parameters have been established for 3T GRE free-running 5D whole-heart coronary MRA. In this study, a Gd injection scheme, RF excitation angles of lipid-insensitive binominal off-resonance RF excitation (LIBRE) pulse for valid fat suppression and continuous data acquisition, and compressed-sensing reconstruction regularization parameters were optimized for contrast-enhanced free-running 5D whole-heart coronary MRA using a GRE sequence at 3T. Using this optimized protocol, contrast-enhanced free-running 5D whole-heart coronary MRA using a GRE sequence is feasible with good image quality at 3T.

Towards a Simplified and Cost-Effective Diagnostic Algorithm for the Surveillance of Intraductal Papillary Mucinous Neoplasms (IPMNs): Can We Save Contrast for Later?

The increased detection of pancreatic cysts in recent years has triggered extensive diagnostic investigations to clarify their potential risk of malignancy, resulting in a large number of patients undergoing numerous imaging follow-up studies for many years. Therefore, there is a growing need for optimization of the current surveillance protocol to reduce both healthcare costs and waiting lists, while still maintaining appropriate sensibility and specificity. Imaging is an essential tool for evaluating patients with intraductal papillary mucinous neoplasms (IPMNs) since it can assess several predictors for malignancy and thus guide further management recommendations. Although contrast-enhanced magnetic resonance imaging (MRI) with magnetic resonance cholangiopancreatography (MRCP) has been widely recommended by most international guidelines, recent results support the use of unenhanced abbreviated-MRI (A-MRI) protocols as a surveillance tool in patients with IPMN. In fact, A-MRI has shown high diagnostic performance in malignant detection, with high sensitivity and specificity as well as excellent interobserver agreement. The aim of this paper is, therefore, to discuss the current available evidence on whether the implementation of an abbreviated-MRI (A-MRI) protocol for cystic pancreatic lesion surveillance could improve healthcare economics and reduce waiting lists in clinical practice without significantly reducing diagnostic accuracy.

Postoperative MRI Findings Following PELD and Their Correlations with Clinical Prognosis are Investigated by Injecting Contrast into Annulus Fibrosus Intraoperatively

Objective

To validate whether a residual mass demonstrated on early postoperative MR after percutaneous endoscopic lumbar discectomy (PELD) is indeed an intraoperatively retained annulus fibrosus, and explore the correlation between imaging changes in the residual mass and clinical prognosis of patients.

Methods

A prospective study of 118 patients were included. During surgery, a contrast medium, Gadopentetate Dimeglumine, was injected around the ruptured annulus fibrosus. The intensity of the T2 signal, the size of the remaining mass (SR), and the cross-sectional area of the spinal canal (SCSA), VAS, and ODI were assessed at preoperative, 1-h (7-day), 6-month, and 12-month postoperative intervals. Based on VAS at 7 days post-surgery, patients were classified into either a non-remission group (Group A, VAS > 3) or a remission group (Group B, VAS ≤ 3).

Results

Six patients who developed recurrent LDH were excluded. A residual mass was detected on MRI 1 h after surgery in 94.6% (106/112). During one year of follow-up, 90.1% (101/112) of the patients displayed fibrous annulus remodeling, although 68.7% (77/112) still exhibited herniation. Significant differences were found in the ODI between Groups A and B one week after surgery (p < 0.001). However, no significant differences were observed in T2 signal intensity, SR, and SCSA at 1-h, 6-month and 12-month post-surgery (p > 0.05) between the two groups. In a multiple linear regression analysis, early postoperative ODI changes were associated with T2 signal (B = -10.22, sig < 0.05), long-term changes were associated with alterations in SR (B = 5.63, sig < 0.05) and SCSA (B = -0.13, sig < 0.05).

Conclusion

The residual mass observed in early postoperative MR images after PELD was the retained annulus fibrosus intraoperatively. Short-term changes in clinical symptoms after PELD were linked to T2 signal intensity, while long-term changes were associated with changes in SR and SCSA.

Magnetic resonance imaging subtraction vs. pre- and post-contrast 3D gradient recalled echo fat suppressed imaging for evaluation of the canine and feline brain

Subtraction magnetic resonance imaging (MRI) has been reported to increase accuracy in the diagnosis of meningeal and inflammatory brain diseases in small animals. 3D T1W gradient recalled echo (GRE) techniques have been proposed as a suitable alternative to conventional spin echo sequences in imaging the canine brain. The aim of this study was to compare subtraction images and paired pre- and post-contrast 3D T1W GRE fat suppressed (FS) images in canine and feline MRI studies using clinical diagnosis as the gold standard. Paired pre- and post-contrast T1W 3D FS GRE images and individual subtraction images of 100 small animal patients were randomized and independently evaluated by 2 blinded observers. Diagnosis categories were "normal," "inflammatory," "neoplastic," and "other." Clinical diagnosis was made in the same categories and served as the gold standard. Image interpretation results were compared to the clinical diagnosis. Interobserver agreement was determined. Clinically, 41 studies were categorized as "normal," 18 as "inflammatory," 28 as "neoplastic," and 13 as "other." The agreement of the pre- and post-contrast GRE images with the gold standard was significantly higher than that of the subtraction images (k = 0.7491 vs. k = 0.5924; p = 0.0075). The largest sources of error were misinterpretation of "other" as "normal" and "normal" as "inflammatory." There was no significant difference between the two observers (p = 0.8820). Based on this study, subtraction images do not provide an advantage to paired pre- and post-contrast FS GRE images when evaluating the canine and feline brain.

Roadmap fusion imaging in percutaneous coronary intervention reduces contrast medium exposure irrespective of investigator's experience level

OBJECTIVES

Dynamic Coronary Roadmap (DCR) is a software tool that creates a real-time dynamic coronary artery overlay on fluoroscopic images. The efficacy of DCR in significantly reducing contrast medium use during percutaneous coronary interventions (PCI) has previously been shown. In this study, we aimed to determine if DCR is equally effective irrespective of the performing investigator's experience level.

METHODS

In this sub-analysis of a monocentric, open-label, randomized trial, 130 patients with hemodynamic relevant coronary type A and B lesions were randomized and contrast medium use was conducted with (+) or without (-) DCR software. PCI was randomly allocated and performed by an investigator with high (A) or medium (B) experience level.

RESULTS

Overall, contrast medium use was significantly reduced by both investigators in the +DCR group, and Investigator B used significantly less contrast medium with the software than Investigator A. The DCR software was not accompanied by increased radiation exposure for the patients or the teams. On the contrary, dose area product was reduced by both investigators, but was significantly reduced by the highly experienced investigator when using DCR. Fluoroscopy time was not different between investigators. Procedural success was 100%. Serious in-hospital adverse events were not observed. One of Investigator A's patients suffered from post-procedural acute kidney injury in the -DCR group.

CONCLUSIONS

DCR significantly reduces contrast medium use during PCI irrespective of investigator's experience level.

Roadmap fusion imaging in percutaneous coronary intervention reduces contrast medium exposure irrespective of investigator's experience level

OBJECTIVES

Dynamic Coronary Roadmap (DCR) is a software tool that creates a real-time dynamic coronary artery overlay on fluoroscopic images. The efficacy of DCR in significantly reducing contrast medium use during percutaneous coronary interventions (PCI) has previously been shown. In this study, we aimed to determine if DCR is equally effective irrespective of the performing investigator's experience level.

METHODS

In this sub-analysis of a monocentric, open-label, randomized trial, 130 patients with hemodynamic relevant coronary type A and B lesions were randomized and contrast medium use was conducted with (+) or without (-) DCR software. PCI was randomly allocated and performed by an investigator with high (A) or medium (B) experience level.

RESULTS

Overall, contrast medium use was significantly reduced by both investigators in the +DCR group, and Investigator B used significantly less contrast medium with the software than Investigator A. The DCR software was not accompanied by increased radiation exposure for the patients or the teams. On the contrary, dose area product was reduced by both investigators, but was significantly reduced by the highly experienced investigator when using DCR. Fluoroscopy time was not different between investigators. Procedural success was 100%. Serious in-hospital adverse events were not observed. One of Investigator A's patients suffered from post-procedural acute kidney injury in the -DCR group.

CONCLUSIONS

DCR significantly reduces contrast medium use during PCI irrespective of investigator's experience level.

Modified abaxial sesamoid nerve block provides enhanced proximal diffusion compared to basisesamoid block and lower proximal diffusion than traditional low plantar nerve block in equine hind limbs: ex vivo and in vivo study

OBJECTIVE

To determine the proximal diffusion distance of radiopaque contrast medium and mepivacaine/methylene blue solution and incidence of inadvertent intrasynovial and intravascular injections of modified sesamoid nerve block (MASB) when compared with traditional plantar nerve analgesia techniques of the equine distal hind limb.

SAMPLE

Ex vivo model: 18 hind limbs; and in vivo model: 5 horses in a crossover study.

METHODS

In the ex vivo model, a mepivacaine/methylene blue solution was used to compare the diffusion distance between MASB, basisesamoid block (BSB), and traditional low plantar block (TLPB). Ten minutes after injection, skin was dissected and proximal diffusion distance of the dye patch was measured. In the in vivo model, both hind limbs were injected with radiopaque contrast medium with either MASB or TLPB. Ten minutes after injection, a radiograph was acquired and the proximal diffusion of the contrast medium patch was measured.

RESULTS

In the ex vivo model, solution proximal diffusion distance for MASB was significantly longer than BSB (P < .050) and significantly shorter than TLPB (P < .050). Both techniques reached the proximal aspect of DFTS similarly (P = .289), and no difference in the incidence of intrasynovial or intravascular injections was observed (P = .292). In the in vivo model, contrast medium proximal diffusion of MASB was significantly shorter than TLPB (P < .050). The proportion of injections that diffused subcutaneously to the proximal aspect of the proximal pouch of the DFTS was not significantly different between techniques (P = .136). No difference in the incidence of DFTS intrasynovial or intravascular injections was observed (P = .305).

CLINICAL RELEVANCE

MASB presented significantly more proximal diffusion than BSB and less proximal diffusion than TLPB, consistently reached the proximal aspect of DFTS, and presented a very low risk of intrasynovial and intravascular injections.

[Contrast Induced Encephalopathy after carotid percutaneous transluminal angioplasty in a patient with end stage renal disease undergoing peritoneal Dialysis]

Introduction. Contrast Induced Encephalopathy (CIE) belongs to Major Adverse Renal and Cardiovascular Events (MARCE) after iodinated contrast medium (IOCM), especially for high-risk patients with several comorbidities such as hypertension, diabetes, heart failure, and Chronic Kidney Disease (CKD). We report a case of CIE in a Peritoneal Dialysis (PD)-patient. Case report. A 78-year-old, affected by diabetes, hypertension, chronic heart failure, and End Stage Renal Disease (ESRD) treated with PD, underwent a carotid Percutaneous Angioplasty (PTA). Immediately after the exam, he developed mental confusion and aphasia. Encephalic CT scan and MRI excluded acute ischemia or hemorrhage but showed cerebral oedema. Mannitol and steroids were administered and additional PD exchange was performed with depurative aim. Within 2 days the patient completely recovered. Discussion. CIE mimics severe neurological diseases. It should be considered as a differential diagnosis if symptoms occur immediately after administration of IOCM, especially in high-risk patients and in case of intra-arterial injection. Clinical presentation includes transient cortical blindness, aphasia, focal neurological defects, and confusion. CIE is often a diagnosis of exclusion, and imaging plays a significant role. Symptoms generally resolve spontaneously within 24-48h, rarely in few days. Symptomatic therapy, including mannitol and steroids could be considered. In literature, CIE is reported only in a few patients affected by ESRD treated with chronic HD, and our is the first available case of a patient treated with chronic PD who developed this rare complication.

Comparative diagnostic imaging in giant African land snails (Achatinidae)

Giant African land snails (GALS) have become increasingly popular, for example, as pets or in kindergartens in Europe, but little is known about their clinically relevant anatomy, diseases, or further details in diagnostic imaging. The present study focuses on the techniques and image interpretation of radiography, computed tomography, and sonography in GALS. The aim of the study is to find the most appropriate imaging tool to visualize the various organs within the mantle cavity (also known as visceral mass) in GALS. The detailed anatomy of GALS is presented with numerous figures of the different imaging techniques. The sensory organs and nervous system will not be part of the present study.

Incidences of and risk factors for clinical and subclinical contrast-associated acute kidney injury in patients who underwent neuroendovascular surgery

BACKGROUND

Contrast-associated acute kidney injury (CA-AKI) can develop after intravascular administration of iodinated contrast media. Neutrophil gelatinase-associated lipocalin (NGAL) is an early marker for AKI that helps to detect subclinical CA-AKI. We investigated the incidence of and risk factors for clinical and subclinical CA-AKI in patients who underwent neuroendovascular surgery.

METHODS

We retrospectively investigated 228 patients who underwent neuroendovascular surgery in 2020. Changes in serum creatinine and urine output were used to detect clinical CA-AKI. Urine NGAL concentration was used to detect subclinical CA-AKI in 67 out of 228 patients.

RESULTS

In 228 patients, serum creatinine, hemoglobin, hematocrit, total protein, and blood urea nitrogen (BUN) decreased significantly (p < 0.001) after surgery. However, serum creatinine decreased less significantly (p < 0.05) than hemoglobin, hematocrit, total protein, and BUN on postoperative Day 3. Two patients out of 228 developed clinical CA-AKI, and seven patients out of 67 with urine NGAL measurements developed subclinical CA-AKI. Multivariate regression analysis revealed that diabetes mellitus and carotid artery stenosis were significantly (p < 0.05) associated with the development of clinical and/or subclinical CA-AKI.

CONCLUSION

There was a large difference between the incidences of clinical CA-AKI (0.88%) and subclinical CA-AKI (10.4%). The difference might have primarily resulted from the different sensitivities between serum creatinine and urine NGAL and possibly from underestimation of the incidence of clinical AKI due to a postoperative decrease in serum creatinine caused by hemodilution. In addition to diabetes mellitus, carotid artery stenosis could also be a risk factor for CA-AKI.

Development and Validation of a Risk Model for Predicting Contrast-Associated Acute Kidney Injury in Patients With Cancer: Evaluation in Over 46,000 CT Examinations

BACKGROUND. Patients with cancer undergo frequent CT examinations with iodinated contrast media and may be uniquely predisposed to contrast-associated acute kidney injury (CA-AKI). OBJECTIVE. The purpose of this study was to develop and validate a model for predicting the risk of CA-AKI after contrast-enhanced CT in patients with cancer. METHODS. This retrospective study included 25,184 adult patients (12,153 men, 13,031 women; mean age, 62.3 ± 13.7 [SD] years) with cancer who underwent 46,593 contrast-enhanced CT examinations between January 1, 2016, and June 20, 2020, at one of three academic medical centers. Information was recorded regarding demographics, malignancy type, medication use, baseline laboratory values, and comorbid conditions. CA-AKI was defined as a 0.3-mg/dL or greater increase in serum creatinine level from baseline within 48 hours after CT or a 1.5-fold or greater increase in the peak measurement within 14 days after CT. Multivariable models accounting for correlated data were used to identify risk factors for CA-AKI. A risk score for predicting CA-AKI was generated in a development set (n = 30,926) and tested in a validation set (n = 15,667). RESULTS. CA-AKI occurred after 5.8% (2682/46,593) of CT examinations. The final multivariable model for predicting CA-AKI included hematologic malignancy, diuretic use, angiotensin-converting enzyme inhibitor or angiotensin receptor blocker use, chronic kidney disease (CKD) stage 3a, CKD stage 3b, CKD stage 4 or 5, serum albumin level less than 3.0 g/dL, platelet count less than 150 × 103/μL, 1+ or greater proteinuria on baseline urinalysis, diabetes mellitus, heart failure, and contrast medium volume 100 mL or greater. A risk score (range, 0-53 points) was generated with these variables. The most points (13) were for CKD stage 4 or 5 and for albumin level less than 3 g/dL. The frequency of CA-AKI progressively increased in higher risk categories. For example, in the validation set, CA-AKI occurred after 2.2% of CT examinations in the lowest risk category (score ≤ 4) and after 32.7% of CT examinations in the highest risk category (score ≥ 30). The Hosmer-Lemeshow test result indicated that the risk score was a good fit (p = .40). CONCLUSION. A risk model in which readily available clinical data are used to predict the likelihood of CA-AKI after contrast-enhanced CT in patients with cancer was developed and validated. CLINICAL IMPACT. The model may help facilitate appropriate implementation of preventive measures in the care of patients at high risk of CA-AKI.

J wave dynamicity during coronary angiography and intracoronary acetylcholine administration

BACKGROUND

J-waves may be observed during coronary angiography (CAG) or intracoronary acetylcholine (ACh) administration, but their significance is unknown.

METHODS

Forty-nine patients, 59.1 ± 11.5 years old and 59% male, were studied on suspicion of vasospastic angina, and J wave dynamicity was compared between CAG and Ach administration.

RESULTS

Diagnostic (≥0.1 mV) or nondiagnostic (<0.1 mV) J waves in 9 and 3 patients, respectively, were augmented, and J waves were newly observed in 2 patients during CAG and Ach administration. Similar changes in the J-wave amplitude were observed: from 0.10 ± 0.09 mV to 0.20 ± 0.15 mV (p < .002) and from 0.10 ± 0.10 mV to 0.20 ± 0.16 mV (p < .001) during CAG and Ach administration, respectively. J waves were located in the inferior leads and changed only during the right coronary interventions. In the remaining 35 patients, J waves were absent before and during the coronary interventions. Augmentation of J waves was found when the RR interval was shortened in some patients. Injection of anoxic media into the coronary artery might induce a conduction delay from myocardial ischemia that manifests as augmentation or new occurrence of J waves.

CONCLUSIONS

Both CAG and intracoronary Ach administration affected J waves similarly in the same individuals. A myocardial ischemia-induced conduction delay may be responsible for the changes in J waves, but further studies are needed.

Dual-modality and Noninvasive Diagnostic of MNP-PEG-Mn Nanoprobe for Renal Fibrosis Based on Photoacoustic and Magnetic Resonance Imaging

To date, imaging-guided multimodality therapy is important to improve the accuracy of the diagnosis of renal fibrosis, and nanoplatforms for imaging-guided multimodality diagnosis are gaining more and more attention. There are many limitations and deficiencies in clinical use for early-stage diagnosis of renal fibrosis, and multimodal imaging can contribute more thoroughly and provide in-detail information for effective clinical diagnosis. Melanin is an endogenous biomaterial, and we developed an ultrasmall particle size melanin nanoprobe (MNP-PEG-Mn) based on photoacoustic (PA) and magnetic resonance (MR) dual-modal imaging. MNP-PEG-Mn nanoprobe, with the average diameter about 2.7 nm, can be passively targeted for accumulation in the kidney, and it has excellent free radical scavenging and antioxidant abilities without further exacerbating renal fibrosis. Using the normal group signal as a control, the dual-modal imaging results showed that the MR imaging (MAI) and PA imaging (PAI) signals reached the strongest at 6 h when MNP-PEG-Mn entered the 7 day renal fibrosis group via the left vein of the tail end of the mice; however, the strength of the dual-modal imaging signal and the gradient of signal change were significantly weaker in the 28 day renal fibrosis group than in the 7 day renal fibrosis group and normal group. The phenomenon preliminarily indicates that as a PAI/MRI dual-modality contrast medium candidate, MNP-PEG-Mn has outstanding ability in clinical application potential.

Oil-based or saline contrast for sono-hysterosalpingography in infertile women: a pilot randomized controlled double blind trial

Objective

To determine the feasibility, safety, and outcomes of an oil-based, iodinated contrast using office-based, ultrasound-imaged hysterosalpingography in women with infertility.

Design

Randomized Controlled Double Blind Clinical Trial.

Setting

Academic health center.

Interventions

Tubal flushing with oil-based contrast medium (Lipiodol UF) versus saline.

Main Outcome Measures

Ongoing pregnancy rate, pain, quality of life, and thyroid function.

Results

Forty-eight patients (24 in each group) were analyzed. The groups were well-matched at baseline. Ongoing pregnancy was noted in 17% (4/24) of the oil-contrast group versus 37% (9/24) in the saline group. Saline group patients more frequently initiated infertility therapy in the six-month follow-up period (saline, 67% vs. oil, 33%), and no serious adverse events in either group. There were no differences in pain from the procedure between groups. There were no differences in thyroid function tests postprocedure between groups, but within the oil-contrast group, there was a slight increase in thyroid-stimulating hormone (post vs. preratio of geometric means: 1.18; 95% confidence interval [CI], 1.02-1.38) and decrease in Free T4 (postdifference vs. predifference in means: 0.08 ng/dL; 95% CI, -0.14 to -0.01). Immediately after the test, the physicians correctly guessed 79% of oil and 71% of saline randomization assignments, whereas patients correctly guessed 63% of oil and 38% of saline.

Conclusions

This pilot study demonstrates the safety and feasibility of giving an oil-based contrast medium during ultrasound-imaged hysterosalpingography. Pregnancies were seen after oil-based administration, and this contrast is associated with minor thyroid function impairment.

Contrast-enhanced computed tomography and cross-sectional anatomy of the trunk in the brownbanded bamboo shark (Chiloscyllium punctatum)

Computed tomography (CT) is used in veterinary medicine for the diagnosis of bones and soft tissue diseases in various species. In addition, CT has recently been used to diagnose aquatic animals, including Selachimorpha, which are difficult to diagnose out of water. However, because Selachimorpha do not have adipose tissue in the coelomic cavity, the coelomic organs cannot be fully identified using non-contrast CT (NCCT). The aim of this study is to present the anatomical features of the cadaver, NCCT, and contrast-enhanced CT (CECT) as well as the change in CT values of the coelomic organs and musculature of the brownbanded bamboo shark. NCCT scans were performed under anaesthesia in one male and one female shark. CECT was performed 30 min after iopamidol was administered intravenously. The sharks were euthanized, frozen at -20°C, and sliced in the same position in which they were scanned. Using electric band saw, 10-mm transversal sections were obtained. The anatomical structures of both males and females were identified by transversal sections, and CT images homologous to transversal sections were then selected. Sagittal and coronal CECT images were also obtained to facilitate understanding of the location and size of coelomic organs. Although bone structure and air in organs could be sufficiently discriminated on NCCT image, the coelomic organs were almost indistinguishable. On the other hand, CECT images obtained sufficient contrast to identify most coelomic organs in addition to bone and air. The results provide an atlas of a cross-sectional anatomy and CECT images, which is useful information for the medical diagnosis of coelomic organs in live Selachimorpha.

Urinary NGAL, IGFBP-7, and TIMP-2: novel biomarkers to predict contrast medium-induced acute kidney injury in children

Background

Serum creatinine (SCr) is unreliable in detecting acute changes in kidney function. Early recognition of contrast-induced acute kidney injury (CI-AKI) can provide better opportunities for preventive interventions. Therefore, the purpose of this study is to examine the value of the combined detection of urinary neutrophil gelatinase-associated lipocalin (NGAL), insulin-like growth factor binding protein-7 (IGFBP-7), and tissue inhibitor of metalloproteinase-2 (TIMP-2) in the early diagnosis of children with CI-AKI.

Methods

A prospective, single-center clinical trial was performed and included 172 children aged 0–18 years. The dynamic changes of urinary NGAL, IGFBP-7, and TIMP-2 levels in children with intravascular injection of contrast medium were investigated to determine whether they can diagnose CI-AKI early.

Results

CI-AKI occurred in 20 of 137 enrolled patients, and the incidence was 14.59%. In the CI-AKI group, urinary levels of NGAL, IGFBP-7, TIMP-2, and [IGFBP-7]*[TIMP-2] were significantly increased 2 h after angiography and remained at high levels at 6 h. Using a cutoff value of 36.274 ng/mL, the specificity was 70.0%, and the sensitivity was 68.4% for the prediction of CI-AKI, which was excellent for urinary NGAL. When both urinary IGFBP-7 and TIMP-2 were used together, urinary [IGFBP-7]*[TIMP-2] at 0.417(ng/mL)²/1000 was regarded as the cutoff value. The specificity was 80.0%, and the sensitivity was 81.2%.

Conclusions

NGAL, IGFBP-7, and TIMP-2 concentrations in the urine of children after receiving injections of contrast medium increased faster than SCr and had good clinical value for the early diagnosis of CI-AKI in children. The combination of IGFBP-7 and TIMP-2 was better than either analyte alone.

Canadian Association of Radiologists Guidance on Contrast Associated Acute Kidney Injury

Iodinated contrast media (ICM) is one of the most frequently administered pharmaceuticals. In Canada, over 5.4 million computed tomography (CT) examinations were performed in 2019, of which 50% were contrast enhanced. Acute kidney injury (AKI) occurring after ICM administration was historically considered a common iatrogenic complication which was managed by screening patients, prophylactic strategies, and follow up evaluation of renal function. The Canadian Association of Radiologists (CAR) initially published guidelines on the prevention of contrast induced nephropathy in 2007, with an update in 2012. However, new developments in the field have led to the availability of safer contrast agents and changes in clinical practice, prompting a complete revision of the earlier recommendations. This revised guidance document was developed by a multidisciplinary CAR Working Group of radiologists and nephrologists, and summarizes changes in practice related to contrast administration, screening, and risk stratification since the last guideline. It reviews the scientific evidence for contrast associated AKI and provides consensus-based recommendations for its prevention and management in the Canadian healthcare context. This article is a joint publication in the Canadian Association of Radiologists Journal and Canadian Journal of Kidney Health and Disease, intended to inform both communities of practice.

Proposal of a novel protocol using estimated cardiac index fractional dose to improve aortic contrast enhancement for early-phase dynamic CT

Maximum aortic computed tomography value (CTV) is difficult to control because of variations in cardiac function and patient physique. Therefore, to improve early-phase aortic enhancement on dynamic computed tomography (CT), we developed an estimated cardiac index fractional dose (eciFD). The eciFD protocol is a novel and original protocol for administering fractional dose (FD), representing the amount of iodine per unit body weight per injection duration, based on cardiac index (cardiac output divided by body surface area) as estimated by age in early-phase dynamic CT. At the time of administration, by selecting FD based on the patient's age and selecting a parameter that can achieve this FD, an aortic CTV ≥300 HU (ACTV≥300) can be obtained. This study aimed to investigate aortic enhancement on CT angiography using the eciFD protocol.This retrospective study investigated 291 consecutive patients who underwent dynamic CT from neck to abdomen after recommendation of the eciFD protocol at our institution. We compared early-phase aortic CTV distributions by scan delay between an eciFD group (eciFD applied, n = 135) and a non-eciFD group (eciFD not applied, n = 80). The effect of eciFD on early-phase ACTV≥300 was evaluated using logistic regression analysis adjusted for several potentially meaningful clinical confounders related to aortic CTV, namely male sex, heart rate ≤80 beats/min, estimated glomerular filtration rate ≤40 mL/min, use of eciFD, bolus tracking (BT), history of myocardial infarction, and order from the emergency center.The eciFD protocol was a significant factor for early-phase ACTV≥300 after adjusting for several confounders (odds ratio 3.03; 95% confidence intervals 1.59-5.77; P = .001). No interaction was seen between BT and eciFD protocol (p for interaction = 0.76). In terms of CTV distribution, with both a fixed scan delay time and BT, the eciFD group showed a high aortic CTV. The combination of eciFD protocol with BT provided a particularly high percentage of patients with ACTV≥300 (86.4%).The eciFD protocol was useful for improving aortic contrast enhancement. These findings need to be validated in a randomized controlled study.

Pseudohemothorax induced by residual contrast medium mimicking aortic dissection rupture

Hemothorax is an urgent condition, and its accurate diagnosis and the identification of the cause are important. Herein, we report a case of a 74-year-old man with end-stage renal disease who was presented with high-concentration pleural effusion owing to residual contrast medium. The case required differentiation from hemothorax owing to an aortic dissection and its rupture. In patients with end-stage renal disease, noncontrast-enhanced computed tomography after contrast-enhanced computed tomography may result in high-concentration pleural effusion owing to the existence of residual contrast medium. This realization is important to determine whether high-concentration pleural effusion symptoms reflect an urgent hemothorax case possibly related to an imminent rupture of an aortic aneurysm or intrathoracic penetration of aortic dissection, and whether invasive procedures, such as thoracentesis, ought to be avoided.

[Can Echocardiography Adjust Corrected Contrast Injection Condition in Coronary CT Angiography?]

PURPOSE

The purposes were to search which factor of cardiac function in echocardiography correlates with the CT value, to correct contrast injection conditions with cardiac function in addition to suppress error in the contrast effect between patients, and to achieve the target CT value (350 HU) in coronary computed tomography angiography (CCTA).

METHODS

In 112 patients (conventional group), the contrast material was administered at a fractional dose (FD) of 21 mgI/kg/s. We measured the aortic CT value in the coronary origin part. In 112 patients (correction group), the contrast material was administered at corrected injection conditions with the most correlated functional factor and CT value.

RESULTS

The CT value of the conventional group was an average of 400.8±51.5 HU. The most correlated factor with the CT value was stroke volume [SV (r=-0.555)]. The CT value of the conventional group was an average of 360±46 HU. The case of the aim CT level was improved from 46% to 74%. In the correction group, the average value of FD was 18.5 mgI/kg/s. This enabled the reduction of the contrast material in 95% of patients.

CONCLUSION

The best correlation was obtained between the CT value of coronary arteries and SV. The contrast medium injection conditions were corrected for cardiac function in addition to body weight. As a result, we were able to control the CCTA target CT value of 300 to 400 HU at our hospital.

Advances in Myocardial Perfusion MR Imaging: Physiological Implications, the Importance of Quantitative Analysis, and Impact on Patient Care in Coronary Artery Disease

Stress myocardial perfusion imaging (MPI) is the preferred test in patients with intermediate-to-high clinical likelihood of coronary artery disease (CAD) and can be used as a gatekeeper to avoid unnecessary revascularization. Cardiac magnetic resonance (CMR) has a number of favorable characteristics, including: (1) high spatial resolution that can delineate subendocardial ischemia; (2) comprehensive assessment of morphology, global and regional cardiac functions, tissue characterization, and coronary artery stenosis; and (3) no radiation exposure to patients. According to meta-analysis studies, the diagnostic accuracy of perfusion CMR is comparable to positron emission tomography (PET) and perfusion CT, and is better than single-photon emission CT (SPECT) when fractional flow reserve (FFR) is used as a reference standard. In addition, stress CMR has an excellent prognostic value. One meta-analysis study demonstrated the annual event rate of cardiovascular death or non-fatal myocardial infarction was 4.9% and 0.8%, respectively, in patients with positive and negative stress CMR. Quantitative assessment of perfusion CMR not only allows the objective evaluation of regional ischemia but also provides insights into the pathophysiology of microvascular disease and diffuse subclinical atherosclerosis. For accurate quantification of myocardial perfusion, saturation correction of arterial input function is important. There are two major approaches for saturation correction, one is a dual-bolus method and the other is a dual-sequence method. Absolute quantitative mapping with myocardial perfusion CMR has good accuracy in detecting coronary microvascular dysfunction. Flow measurement in the coronary sinus (CS) with phase contrast cine CMR is an alternative approach to quantify global coronary flow reserve (CFR). The measurement of global CFR by quantitative analysis of perfusion CMR or flow measurement in the CS permits assessment of microvascular disease and diffuse subclinical atherosclerosis, which may provide improved prediction of future event risk in patients with suspected or known CAD. Multi-institutional studies to validate the diagnostic and prognostic values of quantitative perfusion CMR approaches are required.

Electroanatomical Navigation to Minimize Contrast Medium or X-Rays During Stenting: Insights From an Experimental Model

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Contrast media and x-rays used in vascular interventional procedures have been linked to health hazards for patients and medical teams.

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Modified OCT and angioplasty catheters were successful navigated in coronary and carotid arteries using an impedance-sensitive navigation system and used to precisely deliver and implant stents in specified arterial targets without the need for x-ray or contrast medium. Our system achieved an accuracy of 90% and a precision of 1.4mm.

•

This proof-of-principle experiment opens the door to PCI with no contrast medium or X-ray in human through the integration of coronary CT scan and intracoronary imaging technologies within navigation systems.

Stents can be effectively implemented with no x-rays or contrast medium. Modified stents were successfully implanted in 9 of 11 attempted targets (82%) (7 carotid and 4 coronary arteries) using an impedance-sensitive navigation system and optical coherence tomography. Electroanatomical navigation systems can be used to assist interventionalists in performing arterial stenting while minimizing x-ray and contrast use, thereby potentially enhancing safety for both patients and catheterization laboratory staff members.

Comparing feasibility of different tube voltages and different concentrations of contrast medium in coronary CT angiography of overweight patients

OBJECTIVES

To compare image quality, radiation dose, and iodine intake of coronary computed tomography angiography (CCTA) acquired by wide-detector using different tube voltages and different concentrations of contrast medium (CM) for overweight patients.

MATERIALS AND METHODS

A total of 150 overweight patients (body mass index≥25 kg/m2) who underwent CCTA are enrolled and divided into three groups according to scan protocols namely, group A (120 kVp, 370 mgI/ml CM); group B (100 kVp, 350 mgI/ml CM); and group C (80 kVp, 320 mgI/ml CM). The CT values, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and figure-of-merit (FOM) of all images are calculated. Images are subjectively assessed using a 5-point scale. In addition, the CT dose index volume (CTDIvol) and dose length product (DLP) of each patient are recorded. The effective radiation dose (ED) is also calculated. Above data are then statistically analyzed.

RESULTS

The mean CT values, SNR, CNR, and subjective image quality of group A are significantly lower than those of groups B and C (P < 0.001), but there is no significant difference between groups B and C (P > 0.05). FOMs show a significantly increase trend from group A to C (P < 0.001). The ED values and total iodine intake in groups B and C are 30.34% and 68.53% and 10.22% and 16.85% lower than those in group A, respectively (P < 0.001).

CONCLUSION

The lower tube voltage and lower concentration of CM based on wide-detector allows for significant reduction in iodine load and radiation dose in CCTA for overweight patients comparing to routine scan protocols. It also enhances signal intensity of CCTA and maintains image quality.

[Neuroimaging of the endolymphatic hydrops of the labyrinth in severe and moderately severe Meniere's disease]

The results of magnetic resonance imaging (MRI) of the inner ear 24 hours after intratympanic administration of 1 ml of diluted (1:7) contrast substance for gadolinium-based MRI in 43 patients with moderate and severe Meniere's disease course are presented. It has been revealed that in case of severe and moderate course of Meniere's disease endolymphatic hydrops is presented in all departments of labyrinth: cochlea, vestibule, semicircular canals, but is most pronounced in vestibular department of labyrinth: horizontal semicircular canal and vestibule. The neuroimaging method according to the presented protocol is safe and can be applied in a wide practice both to assess the presence and localization, and the degree of expression of the endolymphatic hydrops.

Use of contrast-enhanced computed tomography to detect kidney infarction in dogs

Background

Kidney infarction is a renovascular disease diagnosed by contrast‐enhanced computed tomography (CECT) in humans.

Objectives

To describe the frequency of kidney infarction and to determine the detection of kidney infarction with CECT in dogs.

Animals

Eight hundred and twenty‐six abdominal CECT studies of 826 dogs.

Methods

A cross‐sectional retrospective study. Dogs with abdominal CT scans including CECT were retrospectively retrieved. Kidney infarction was classified into 3 grades based on the extent of infarction relative to total kidney area. The location and number of kidney infarctions in each kidney were expressed as number and percentage. The ability of visualization of kidney infarction in each multiplanar reconstruction (MPR) image plane was evaluated by agreement of 2 observers.

Results

The frequency of kidney infarction in dogs was 3.15% (26/826 dogs; 95% CI = 2.05‐4.61). Most kidney infarctions were classified as grade 1, or the lesions were less than 25% of the kidney (47/56, 83.93%) and most were detected at the caudal pole of the kidney (31/56, 55.35%) on the sagittal plane. On MPR image planes, the sagittal plane had the highest proportion (34/56, 60.71%) of excellent visual category to detect kidney infarction.

Conclusions and Clinical Importance

The CECT, especially the sagittal plane, is a useful diagnostic tool for the detection of kidney infarction in dogs.

Endovascular Treatment Using a Small Amount of Contrast Medium in a Patient with a Posterior Communicating Artery Ruptured Dissecting Aneurysm and Chronic Kidney Disease: A Case Report

Objective

We report a rare case of a patient with a ruptured posterior communicating artery (P-com A) dissecting aneurysm and chronic kidney disease (CKD) treated by endovascular embolization using a small amount of contrast medium.

Case Presentation

An 88-year-old female patient had sudden onset of headache and vomit due to subarachnoid hemorrhage. MRI revealed a ruptured dissecting aneurysm of the right P-com A. The patient had CKD of severity grade 4. Endovascular treatment was performed using only 10 mL of diluted contrast medium with injection through a microcatheter. The postoperative course was uneventful, and no deterioration of renal function occurred.

Conclusion

With minimal amount of contrast medium, endovascular treatment could be safely and effectively performed for patients with P-com A dissecting aneurysms and severe CKD.

Injection rate of contrast medium affects diagnostic ability of dynamic contrast-enhanced magnetic resonance imaging for endometrial carcinoma: a prospective cohort study

Background

Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) can obtain semi-quantitative or quantitative parameters of tumors by capturing the images before and after injection of contrast medium. However, there has been no further research on the effect of flow rate of contrast medium on image quality and parameter sensitivity of DCE-MRI in endometrial carcinoma (EC).

Methods

This was a prospective cohort study enrolling patients who were suspected of EC between January 2018 and June 2020. The baseline data of participants were collected. Post-surgical histological examination acted as the gold standard of EC diagnosis and some characteristics of tumors were recorded. We calculated 3 important parameters of DCE-MRI, including volume transfer constant (K^trans), flux rate constant (K_ep), and extravascular extracellular volume fraction (V_e), according to the MRI system. The image quality in DCE-MRI imaging was evaluated according to contrast, resolution, artifact, signal-to-noise ratio, and scanning time. To evaluate the diagnostic ability of DCE-MRI with different injection rate, receiver operating characteristic (ROC) curve was generated and the area under curve (AUC) was calculated.

Results

According to the different injection rate of contrast medium, participants were divided into three groups, including 2, 3, and 4 mL/s group. It was found that there were more grade 1 EC in the 3 mL/s group (52.4%) than other two groups (34.3% and 23.3%, respectively), and the difference was significant (P=0.021). No other significant differences were found among all other variables. It was found that K^trans was much higher in the 4 mL/s group than in other two groups (P<0.001). Also, V_e was much higher in the 4 mL/s group than in other two groups (P<0.001). However, no significant difference was found in K_ep between three groups (P=0.633). Besides, the 4 mL/s group had the highest quality of all three groups (P<0.001). The sensitivity, specificity, and accuracy were highest in 4 mL/s group. The AUC in three groups were 0.822, 0.832, and 0.888 in the 2, 3, and 4 mL/s group, respectively.

Conclusions

The DCE-MRI measurement is useful for the diagnosis of EC, and faster injection rate may be beneficial to improve diagnostic accuracy and image quality.

Computed tomography contrast enhancement pattern of the uterus in premenopausal women in relation to menstrual cycle and hormonal contraception

BACKGROUND

There are different types of computed tomography (CT) contrast enhancement patterns of the uterus. It is not known whether these are hormonally dependent.

PURPOSE

To assess the relationship between these patterns and the menstrual cycle in non-users of hormonal contraception, and the possible impact of hormonal contraception.

MATERIAL AND METHODS

Prospective observational study of abdominal CT scans of 53 premenopausal women of whom 28 were non-users and 25 users of hormonal contraception. The non-users were divided according to menstrual cycle phase: follicular (n = 12); ovulatory (n = 1); and luteal (n = 12). The pattern and intensity of contrast enhancement of the uterine myometrium were assessed.

RESULTS

The dominant pattern of contrast enhancement of the myometrium was the diffuse homogeneous type in both non-users and users. The intensity of the enhancement measured in Hounsfield units (HU) was higher in the follicular phase (median 102, range 73-130) compared to the luteal phase in non-users (median 92, range 57-130); however this was not statistically significant (P = 0.2). The HU values observed in users (median 95, range 45-160) were at the same levels compared to those of the luteal phase in non-users.

CONCLUSION

The dominant pattern of contrast enhancement in the portal venous phase of the myometrium in fertile ages is the diffuse homogeneous type and is independent of menstrual cycle phase or the use of hormonal contraception. However, these factors seem to play a role in the intensity of contrast enhancement, with a tendency of higher HU values in the follicular phase of non-users.

A preprocedural risk score predicts acute kidney injury following primary percutaneous coronary intervention

BACKGROUND

Reliable preprocedural risk scores for the prediction of Contrast-Induced Acute Kidney Injury (CI-AKI) following Percutaneous Coronary Intervention (pPCI) in patients with ST-elevation myocardial infarction (STEMI) are lacking. Aim of this study was to derive and validate a preprocedural Risk Score in this setting.

METHODS

Two prospectively enrolled patient cohorts were used for derivation and validation (n = 3,736). CI-AKI was defined as creatinine increase ≥0.5 mg/dl <72 h postpPCI. Odds ratios from multivariable logistic regression model were converted to an integer, whose sum represented the Risk Score.

RESULTS

Independent CI-AKI predictors were: diabetes, Killip class II-III (2 points each), age > 75 years, anterior MI (3 points), Killip class IV (4 points), estimated GFR < 60 ml/min/1.73m² (5 points). The Risk Score c-statistic was 0.84 in both cohorts. Compared with patients with Risk Score ≤ 4, the relative risks of CI-AKI among patients scoring 5-9 were 6.2 (derivation cohort) and 7.1 (validation cohort); among patients scoring ≥10, 19.8, and 21.4, respectively.

CONCLUSIONS

Among STEMI patients, a simple preprocedural Risk Score accurately and reproducibly predicted the risk of CI-AKI, identifying ¼ of patients with a seven-fold risk and 1/10 of patients with a 20-fold risk. This knowledge may help tailored strategies, including delaying revascularization of nonculprit vessels in patients at high risk of CI-AKI.

Contrast-induced early repolarization pattern and ventricular fibrillation

Malignant arrhythmias during coronary angiography consist a complication of the procedure. Clinicians should be aware that intracoronary infusion of contrast medium can lead to physiological changes that lower the ventricular fibrillation threshold.

Accuracy of abbreviated multiparametric MRI-derived protocols in predicting local staging of prostate cancer in men undergoing radical prostatectomy

BACKGROUND

Abbreviated magnetic resonance imaging (aMRI) protocols have emerged as an alternative to multiparametric MRI (mpMRI) to reduce examination time and costs.

PURPOSE

To compare multiple aMRI protocols for predicting pathological stage ≥T3 (≥pT3) prostate cancer (PCa).

MATERIAL AND METHODS

One hundred and eight men undergoing staging mpMRI before radical prostatectomy (RP) were retrospectively evaluated. 3.0-T imaging was performed with a 32-channel surface coil and a protocol including diffusion-weighted imaging (DWI), transverse T2-weighted (tT2W) imaging, coronal T2W (cT2W) imaging, sagittal T2W (sT2) imaging, and dynamic contrast-enhanced (DCE) imaging. Two readers independently assessed whether any MRI observation showed stage ≥T3 on each sequence (reading order: DWI, cT2W, tT2W, sT2W, DCE). Final stage was assessed by matching readers' assignments to pathology, and combining them into eight protocols: DWI + tT2W, DWI + cT2W + tT2W, DWI + tT2W + sT2W, DWI + cT2W + tT2W + sT2W, DWI + tT2W + DCE, DWI + cT2W + tT2W + DCE, DWI + tT2W + sT2W + DCE, and mpMRI. Diagnostic accuracy and inter-reader agreement for aMRI protocols were calculated.

RESULTS

Prevalence of ≥pT3 PCa was 31.5%. Sensitivity, specificity, positive (PPV) and negative predictive value (NPV) of aMRI protocols were comparable to mpMRI for R1. Sensitivity was 74.3% (95% confidence interval [CI] 64.8-72.0) to 77.1% (95% CI 67.9-84.4), and NPV 86.8% (95% CI 78.6-92.3) to 88.1% (95% CI 80.1-93.3). All accuracy measures of the various aMRI protocols were similar to mpMRI also for R2, albeit all slightly lower compared to R1. On a per-protocol basis, there was substantial inter-reader agreement in predicting stage ≥pT3 (k 0.63-0.67).

CONCLUSION

When comparing the diagnostic accuracy of multiple aMRI protocols against mpMRI for predicting stage ≥pT3 PCa, the protocol with the fewest sequences (DWI + tT2W) is apparently equivalent to standard mpMRI.

Contrast Administration Impacts CT-Based Radiomics of Colorectal Liver Metastases and Non-Tumoral Liver Parenchyma Revealing the "Radiological" Tumour Microenvironment

The impact of the contrast medium on the radiomic textural features (TF) extracted from the CT scan is unclear. We investigated the modification of TFs of colorectal liver metastases (CLM), peritumoral tissue, and liver parenchyma. One hundred and sixty-two patients with 409 CLMs undergoing resection (2017–2020) into a single institution were considered. We analyzed the following volumes of interest (VOIs): The CLM (Tumor-VOI); a 5-mm parenchyma rim around the CLM (Margin-VOI); and a 2-mL sample of parenchyma distant from CLM (Liver-VOI). Forty-five TFs were extracted from each VOI (LIFEx^®®). Contrast enhancement affected most TFs of the Tumor-VOI (71%) and Margin-VOI (62%), and part of those of the Liver-VOI (44%, p = 0.010). After contrast administration, entropy increased and energy decreased in the Tumor-VOI (0.93 ± 0.10 vs. 0.85 ± 0.14 in pre-contrast; 0.14 ± 0.03 vs. 0.18 ± 0.04, p < 0.001) and Margin-VOI (0.89 ± 0.11 vs. 0.85 ± 0.12; 0.16 ± 0.04 vs. 0.18 ± 0.04, p < 0.001), while remaining stable in the Liver-VOI. Comparing the VOIs, pre-contrast Tumor and Margin-VOI had similar entropy and energy (0.85/0.18 for both), while Liver-VOI had lower values (0.76/0.21, p < 0.001). In the portal phase, a gradient was observed (entropy: Tumor > Margin > Liver; energy: Tumor < Margin < Liver, p < 0.001). Contrast enhancement affected TFs of CLM, while it did not modify entropy and energy of parenchyma. TFs of the peritumoral tissue had modifications similar to the Tumor-VOI despite its radiological aspect being equal to non-tumoral parenchyma.

Injection of contrast medium through a delivery sheath reveals interventricular septal vascular injury in a case of left bundle branch pacing

A 70-year-old woman with symptomatic bradycardia caused by persistent atrial fibrillation and atrioventricular block was referred to our institution for pacemaker implantation. After we failed to obtain adequate His bundle capture thresholds (>2.5 V at 1.0 ms) at three pacing sites, left bundle branch pacing was attempted as an alternative technique. The tip of the 3830 lead was screwed towards the left side of the interventricular septum. Contrast medium was injected through the C315 sheath, which was placed close to the right side of the interventricular septum to determine the exact depth of the 3830 lead inside the septum. Unexpectedly, the vessels in the interventricular septum were revealed by the contrast, which showed that the lead had penetrated one of the septal vessels. To the best of our knowledge, this is the first reported case of a patient in whom injection of a contrast agent through a delivery sheath showed damage to the interventricular septal vessels. Findings from this case suggest that injection of contrast medium through a C315 sheath that is placed close to the interventricular septum is a potential method for excluding damage to interventricular septal vessels.

Application of 70 kVp in abdominal CT angiography to reduce both radiation and contrast dosage and improve patient comfort for children

BACKGROUND

Low-tube voltage scanning improves CT attenuation value of contrast medium (CM). Thus, we hypothesized that 70 kVp in pediatric abdominal CT angiography (CTA) could be used to reduce both radiation and CM dose and improve patient comfort at the same time.

OBJECTIVE

To evaluate the feasibility of using 70 kVp in pediatric abdominal CTA to reduce radiation dose and CM dose and improve patient care for children.

MATERIALS AND METHODS

Forty-six children needing abdominal CTA were enrolled in the study group using low-dose scanning protocol with 70 kVp and 0.7-1.1 ml/kg contrast dose, and reconstructed with 50%ASIR-V. They were compared with other 46 children in control group with matching body weight and underwent conventional CT scans with 100 kVp, 1.2-1.8 ml/kg contrast dose and reconstructed using 50%ASIR. Image quality of large vessels was evaluated using a 5-point scale. CT value and standard deviation of descending aorta (Ao) was measured, and signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Radiation dose, contrast dose, the maximum injection pressure between the two groups were also compared.

RESULTS

Score for displaying large vessels by 70 kVp images was 3.91±0.28, lower than that (4.17±0.38) of the control group (p < 0.05), but fully met the diagnostic requirements. CT value of Ao was 390.87±86.79HU in study group, which is higher than 343.93±49.94HU in control group, while there was no difference in SNR and CNR between two groups; the radiation dose, contrast dosage and injection pressure of the study group were 1.23±0.39mGy, 12.67±7.27 ml and 43.83±17.16psi, respectively, which are significantly lower than the 1.95±0.37mGy, 22.67±7.39 ml, and 77.59±19.68psi of control group.

CONCLUSION

Use of 70 kVp in pediatric abdominal CTA provides diagnostic quality images while significantly reduce radiation and contrast dose, as well as injection pressure to improve patient comfort for children.

Value of multi-detector computed tomography during intra-arterial infusion of contrast medium for locating insulinomas

Objective

This study aimed to evaluate the accuracy of multi-detector computed tomography (CT) during intra-arterial infusion of contrast medium (MDCT-IA) for locating insulinomas.

Methods

This retrospective study included patients with insulinomas who underwent surgery at the Chinese PLA General Hospital in 2013 to 2014. The patients’ case notes and investigation results were reviewed. Preoperative tumor localization was carried out by MDCT-IA and noninvasive methods including MDCT, magnetic resonance imaging (MRI), and contrast-enhanced ultrasound (CEUS). Insulinoma localization using these methods was compared with the histologically confirmed location following surgical excision.

Results

Twelve insulinomas were identified in 12 patients, all of which were treated surgically. All patients received MDCT-IA (100%), 11 patients also underwent MRI (91.7%), seven underwent CT (58.3%), and all 12 underwent CEUS (100%). Tumor localization was determined successfully in 12/12 patients by MDCT-IA (100%), in 9/11 by MRI (81.8%), 4/7 by CT (57.1%), and 7/12 by CEUS (58.3%). Overall, MDCT-IA correctly localized 100% of the lesions.

Conclusions

MDCT-IA can be used to determine the preoperative localization of insulinomas.

Assessment of intrasynovial injection in horses by contrast-enhanced ultrasonography using air bubbles created by agitation of solution

BACKGROUND

Accuracy of intrasynovial injections can be challenging to assess in a clinical setting in horses. Contrast-enhanced ultrasonography (CEUS) using injectate agitated with air has been used to determine the success rates of synovial injections in human rheumatology.

OBJECTIVES

To assess the diagnostic sensitivity and specificity of CEUS and to describe its clinical use.

STUDY DESIGNS

Cadaveric study followed by a prospective descriptive observational study.

METHODS

Part 1: CEUS was performed following injection of agitated methylene-blue solution targeting 13 different anatomical synovial structures from three equine cadavers. Contrast was seen as hyperechoic dots, patches or lines on ultrasonography. CEUS was classified as positive if contrast was considered to be intrasynovial and negative if contrast was considered to be extrasynovial. A second synoviocentesis was performed to determine if the injection was intrasynovial based on the presence or absence of methylene-blue. Estimates of sensitivity and specificity were calculated. Part 2: CEUS was performed following injection of agitated solutions targeting synovial structures as part of routine investigation and treatment of clinical cases.

RESULTS

Part 1: CEUS was correctly classified as positive or negative in all intrasynovial and extrasynovial injections respectively. The sensitivity estimate was 100% (CI 93%-100%) and the specificity estimates was 100% (CI 16%-100%). Part 2: The technique was used safely for 26 injections (14 horses; 19 different synovial structures) administered to localise or treat lameness. Traumatic intersynovial communications or synovial membrane defects were identified using CEUS in 3 horses.

MAIN LIMITATIONS

The low number of extrasynovial injections in Part 1 resulted in an imprecise specificity estimate.

CONCLUSIONS

In horses, CEUS performed following intended intrasynovial injection can be useful for identifying unsuccessful injections.

MicroRNA as an early diagnostic biomarker for contrast-induced acute kidney injury

Contrast-induced acute kidney injury (CI-AKI) is a common clinical complication and an important cause of increased mortality, prolonged hospitalization, and increased medical costs. For taking effective interventions in CI-AKI, early diagnosis and active prevention are of key importance. Currently, early CI-AKI detection depends on serum creatinine (Scr) levels, which lags behind the actual time of renal injury and seriously affects early diagnosis and interventions. MicroRNA (miRNA) has been found to be a useful biomarker in early CI-AKI diagnosis. Several studies have reported on tissue and time-specific miRNAs in AKI as effective diagnostic biomarkers and potential therapeutic targets, but there are only a few studies on miRNA in CI-AKI. However, these studies are preliminary exploratory investigations on changes in miRNA expression in CI-AKI, and whether these specific miRNAs can be used as biomarkers for early CI-AKI diagnosis and as clinical therapeutic targets requires systematic and in-depth studies. Therefore, more sensitive and specific miRNAs of CI-AKI could be discovered, providing newer options and development directions for early diagnosis and intervention in clinical CI-AKI practice. This review evaluates the research progress on specific miRNAs in the early diagnosis of CI-AKI with an aim of providing basic data for the clinical application of these molecular markers in CI-AKI.

Evaluating the Association between Contrast Medium Dosage and Acute Kidney Injury in Transcatheter Aortic Valve Replacement Using Different Predictive Models

Recent studies have suggested that contrast medium (CM) volume is associated with acute kidney injury (AKI) after transcatheter aortic valve replacement (TAVR). However, in a high-risk elderly TAVR population, the prognostic value and ideal threshold of CM dosage for AKI is unclear. Data of 532 successive TAVR patients (age 81.1 ± 6.8 years, EuroSCORE II 4.8% ± 6.0%) were therefore retrospectively analyzed. Based on a recently published formula, the renal function (preprocedural serum creatinine: SCr) corrected ratio of CM and body weight (CM*SCr/BW) was calculated to determine the risk of postprocedural contrast-associated AKI. AKI occurred in 94 patients (18.3%) and significantly increased 1-year all-cause mortality (23.4% vs. 13.1%; p = 0.001). A significant correlation between AKI and 30-day as well as 1-year all-cause mortality was observed (p = 0.001; p = 0.007). However, no association between CM dosage or the CM*SCr/BW ratio with the occurrence of AKI was seen (p = 0.968; p = 0.442). In our all-comers, all-access cohort, we found no relationship between CM dosage, or the established risk ratio model and the occurrence of postprocedural AKI. Further research needs to be directed towards different pathophysiological causes and preventive measures as AKI impairs short- and long-term survival.

Evaluation of a Tube Voltage-Tailored Contrast Medium Injection Protocol for Coronary CT Angiography: Results From the Prospective VOLCANIC Study

OBJECTIVE. The purpose of this study was to prospectively evaluate, using software support, the feasibility and the quantitative and qualitative image quality parameters of a tube voltage-tailored contrast medium (CM) application protocol for patient-specific injection during coronary CT angiography (CCTA). SUBJECTS AND METHODS. In the Voltage-Based Contrast Media Adaptation in Coronary Computed Tomography Angiography (VOLCANIC-CTA) study, a single-center trial, 120 patients referred for CCTA were prospectively assigned to a tube voltage-tailored CM injection protocol. Automated tube voltage levels were selected in 10-kV intervals and ranged from 70 to 130 kV, and the iodine delivery rate (IDR) was adapted to the tube voltage level using dedicated software. The administered CM volume (370 mg I/mL) ranged from 33 mL at 70 kV (IDR, 0.7 g I/s) to 65 mL at 130 kV (IDR, 1.7 g I/s). Attenuation was measured in the aorta and coronary arteries to calculate quantitative signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), and 5-point scales were used to evaluate overall image quality. Radiation metrics were also assessed and compared among the protocols. RESULTS. The mean age of the study patients was 62.5 ± 11.9 (SD) years. Image quality was rated as diagnostic in all patients. Contrast attenuation peaked at 70 kV (p < 0.001), whereas SNR and CNR parameters showed no significant differences between tube voltage levels (p ≥ 0.085). Additionally, no significant differences in subjective image quality parameters were found among the different protocols (p ≥ 0.139). The lowest radiation dose values were observed in the group assigned to the 70-kV protocol, which had a median radiation effective dose of 2.0 mSv (p < 0.001). CONCLUSION. The proposed tube voltage-tailored injection protocol allows individualized scanning of patients undergoing CCTA and significantly reduces CM and radiation dose while maintaining a high diagnostic image quality.

Effects of a High Dose of the Contrast Medium Iodixanol on Renal Function in Patients Following Percutaneous Coronary Intervention

Iodixanol is associated with lower rates of contrast-induced acute kidney injury (CI-AKI). However, the effects of high volumes of iodixanol on renal function after percutaneous coronary intervention (PCI) have not been fully elucidated. This study evaluates the effects of high-dose (>300 mL) iodixanol on renal function within 72 hours of PCI. We retrospectively reviewed 676 consecutive patients who received high-dose (>300 mL) iodixanol during PCI between October 2015 and December 2017 in 4 centers. Logistic regression analysis was used to identify significant independent predictors for CI-AKI. The incidence of CI-AKI was 3.5% (23/651). In patients administered 300 to 500 mL and >500 mL iodixanol, the incidence of CI-AKI was 3.9% and 1.7%, respectively. In patients with an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m², the incidence of CI-AKI was 2.6%. In high-risk and very high-risk patients, stratified by the Mehran risk score, the incidence of CI-AKI was 3.3% and 4.3%, respectively. In patients received high-dose iodixanol (>300 mL), logistic regression analysis demonstrated that female sex, chronic kidney disease, and eGFR were independent risk factors for CI-AKI, but contrast volume was not. The administration of high (300-500 mL) and very high (>500 mL) dose of iodixanol is associated with low rates of CI-AKI.

Use of Contrast-Enhanced Ultrasonography for the Characterization of Tumor Thrombi in Seven Dogs

Simple Summary

Some neoplasia—such as adrenal and thyroid glands tumors—have been associated with “tumor thrombi” both in humans and dogs. The detection and characterization of these venous tumor thrombi is important for both surgical planning and prognosis. In human medicine, contrast-enhanced ultrasonography (CEUS) is considered an accurate diagnostic technique for differentiating malignant from benign portal vein thrombosis in hepatocellular carcinomas. Data regarding the characteristics of tumor thrombi in dogs are currently lacking. Therefore, the aim of this study was to assess the feasibility of CEUS for the characterization of malignant venous thrombosis in dogs. On the basis of our results, CEUS appeared to be useful in the detection of malignant intravascular invasion; contrast uptake of the thrombus was present in all cases. In addition, CEUS may clearly detect newly formed vessels within the thrombus, and arterial-phase enhancement and washout in the venous phase were the main features in malignant thrombosis in our dogs. As CEUS is an easy to perform, noninvasive technique, its application in the detection of malignant thrombosis in dogs may be used to improve the diagnosis in oncological canine patients.

Abstract

Tumors of adrenal and thyroid glands have been associated with vascular invasions—so-called tumor thrombi, both in humans and dogs. The detection and characterization of venous thrombi is an important diagnostic step in patients with primary tumors for both surgical planning and prognosis. The aim of this study was to describe the use of contrast-enhanced ultrasonography (CEUS) for the characterization of tumor thrombi. Dogs with tumor thrombus who underwent bi-dimensional ultrasound (B-mode US) and CEUS were included. Seven dogs were enrolled in this retrospective case series. On B-mode US, all thrombi were visualized, and vascular distension and thrombus-tumor continuity were seen in three and two cases, respectively. On color Doppler examination, all thrombi were identified, seemed non-occlusive and only two presented vascularity. On CEUS, arterial-phase enhancement and washout in the venous phase were observed in all cases. Non-enhancing areas were identified in the tumor thrombi most likely representing non-vascularized tissue that could potentially be embolized in the lungs after fragmentation of the tumor thrombi. On the basis of these preliminary study, CEUS appeared to be useful for the characterization of malignant intravascular invasion.

[New strategies for prevention and early diagnosis of iodinated contrast-induced nephropathy: a systematic review]

Iodinated contrast-induced nephropathy is one of the most feared complications of percutaneous coronary interventions and is associated with increased cardio-vascular mortality and a faster progression towards end stage renal disease. The effects of the iodinated contrast medium on intra-renal hemodynamics and its direct cytotoxic action on proximal tubular cells contribute synergistically to the pathophysiology of renal damage. Since the therapeutic options are extremely limited, the rapid identification of risk factors and the timely implementation of preventive strategies are mandatory to reduce the incidence of iodinated contrast-induced nephropathy. To date, the criteria for defining and staging contrast medium nephropathy are still based on the increase of serum creatinine and/or contraction of diuresis, which are lacking in specificity and therefore do not allow early diagnosis. The aim of this review is to report the latest evidence on the pathophysiological mechanisms that contribute to renal damage by iodinated contrast medium, on the risk stratification tools and on the new early biomarkers of contrast-induced nephropathy, while also focusing on the most validated prevention strategies.

Accuracy of abbreviated multiparametric MRI-derived protocols in predicting local staging of prostate cancer in men undergoing radical prostatectomy

BACKGROUND

Abbreviated magnetic resonance imaging (aMRI) protocols have emerged as an alternative to multiparametric MRI (mpMRI) to reduce examination time and costs.

PURPOSE

To compare multiple aMRI protocols for predicting pathological stage ≥T3 (≥pT3) prostate cancer (PCa).

MATERIAL AND METHODS

One hundred and eight men undergoing staging mpMRI before radical prostatectomy (RP) were retrospectively evaluated. 3.0-T imaging was performed with a 32-channel surface coil and a protocol including diffusion-weighted imaging (DWI), transverse T2-weighted (tT2W) imaging, coronal T2W (cT2W) imaging, sagittal T2W (sT2) imaging, and dynamic contrast-enhanced (DCE) imaging. Two readers independently assessed whether any MRI observation showed stage ≥T3 on each sequence (reading order: DWI, cT2W, tT2W, sT2W, DCE). Final stage was assessed by matching readers' assignments to pathology, and combining them into eight protocols: DWI + tT2W, DWI + cT2W + tT2W, DWI + tT2W + sT2W, DWI + cT2W + tT2W + sT2W, DWI + tT2W + DCE, DWI + cT2W + tT2W + DCE, DWI + tT2W + sT2W + DCE, and mpMRI. Diagnostic accuracy and inter-reader agreement for aMRI protocols were calculated.

RESULTS

Prevalence of ≥pT3 PCa was 31.5%. Sensitivity, specificity, positive (PPV) and negative predictive value (NPV) of aMRI protocols were comparable to mpMRI for R1. Sensitivity was 74.3% (95% confidence interval [CI] 64.8-72.0) to 77.1% (95% CI 67.9-84.4), and NPV 86.8% (95% CI 78.6-92.3) to 88.1% (95% CI 80.1-93.3). All accuracy measures of the various aMRI protocols were similar to mpMRI also for R2, albeit all slightly lower compared to R1. On a per-protocol basis, there was substantial inter-reader agreement in predicting stage ≥pT3 (k 0.63-0.67).

CONCLUSION

When comparing the diagnostic accuracy of multiple aMRI protocols against mpMRI for predicting stage ≥pT3 PCa, the protocol with the fewest sequences (DWI + tT2W) is apparently equivalent to standard mpMRI.

Ultrasonographically-guided stent placement at the vertebral artery origin without contrast medium: A case report

Although ultrasonographically-guided carotid interventions without contrast medium have been reported in the literature, we found no report regarding stenting of the vertebral artery origin for treatment of stenosis. Here, we report the case of an iodine-allergic patient in whom a stenosis at the origin of the vertebral artery was successfully treated with ultrasonographically-guided stent placement without contrast medium. B-mode longitudinal images were monitored during the insertion of the embolism-protection device, when positioning the stent, and for the evaluation of the stent opening. This technique can be an alternative option in selected patients, especially those allergic to the contrast medium.

DDAH-2 alleviates contrast medium iopromide-induced acute kidney injury through nitric oxide synthase

BACKGROUND

Contrast medium-induced acute kidney injury (CI-AKI) is one of the most common causes of hospital-acquired acute renal failure. However, the pathogenesis of CI-AKI remains unclear. Asymmetric dimethylarginine (ADMA) is an endogenous nitric oxide synthase (NOS) inhibitor that is largely metabolised by dimethylarginine dimethylaminohydroxylase (DDAH) in humans. Two isoforms of DDAH exist, namely, DDAH-1 and DDAH-2. In the present study, we examined whether the DDAH-2/ADMA/NOS pathway is involved in the pathogenesis of CI-AKI.

METHODS AND RESULTS

Exposure to the contrast medium iopromide led to increase in creatinine and blood urea nitrogen (BUN) levels, accumulation of ADMA, increase in reactive oxygen species (ROS) generation, and an inflammatory response in mice kidney tissue. The injection of adenovirus-harbouring DDAH-2 lowered renal ADMA levels and had a reno-protective effect against contrast-medium injury by decreasing cell apoptosis, ROS, and fibrosis. By contrast, contrast medium-induced renal injury was exacerbated in heterozygous DDAH-2 knockout mice. In the in vitro study, overexpression of DDAH-2 increased the levels of nitrite and intracellular cGMP, while the DDAH-2 knockdown induced the opposite effect. These findings were also observed in the in vivo sample.

CONCLUSIONS

Our findings provide the first evidence that the DDAH-2/ADMA/NOS pathway is involved in the pathogenesis of CI-AKI and that the protective effect of DDAH-2 probably arises from the modulation of NOS activity, oxidative stress, and the inflammatory process.