Gadolinium-based Contrast Media Research Articles

A neuromuscular clinician's guide to magnetic resonance neurography.

Magnetic resonance neurography (MRN) is increasingly used in clinical practice for the evaluation of patients with a wide spectrum of peripheral nerve disorders. This review article discusses the technical aspects of MRN highlighting the core sequences performed for clinical care. A robust, high-resolution, heavily T2-weighted fluid-sensitive sequence performed on a 3.0 Tesla magnet system remains the main workhorse MRN sequence. In specific clinical scenarios, adjunct techniques such as diffusion-weighted imaging can be added to a protocol for disease characterization. In addition, gadolinium-based contrast material can also be administered for the purposes of image optimization (suppress adjacent vascular signal) and disease characterization. Technical modifications to field of view and planes of imaging can be made based on the clinical question and discussion with the radiologist(s). On fluid-sensitive MRN sequences, a normal peripheral nerve exhibits iso- to minimally hyperintense signal relative to skeletal muscle with a predictable trajectory, preserved "fascicular" architecture, and tapered caliber from proximal to distal. Peripheral nerve abnormalities on MRN include alterations in signal, caliber, architecture, diffusion characteristics as well as enhancement and provide information regarding the underlying etiology. Although some MRN findings including nerve hyperintensity and long-segmental enlargement are nonspecific, there are certain diagnoses that can be made with high certainty based on imaging including benign peripheral nerve tumors, high-grade peripheral nerve injury, and intraneural ganglia. The purpose of this article is to familiarize a neuromuscular clinician with fundamentals of MRN acquisition and interpretation to facilitate communication with the neuromuscular radiologist and optimize patient care.

Efficacy of native T1 mapping for patients with non-ischemic cardiomyopathy and ventricular functional mitral regurgitation undergoing transcatheter edge-to-edge repair

Abstract Background The objectives of this study were to investigate the efficacy of LV myocardial damage assessment by native T1 mapping obtained with cardiac magnetic resonance (CMR) for symptomatic heart failure (HF) patients with non-ischemic cardiomyopathy (NICM) and ventricular functional mitral regurgitation (VFMR) undergoing transcatheter edge-to-edge repair (TEER). Methods We studied 40 symptomatic HF patients with NICM and VFMR undergoing TEER. LV myocardial damage was defined as the native T1 Z-score which was converted from native T1 value obtained with CMR before TEER. The primary endpoint was defined as first re-hospitalization for HF or cardiovascular death over a median follow-up period of 12 months after TEER. Results Multivariable Cox-proportional hazards analysis showed that a native T1 Z-score was the only independent parameter associated with cardiovascular events (hazard ratio: 3.40, 95% confidential interval: 1.51-7.67), and patients with native T1 Z-score < 2.41 experienced significantly fewer cardiovascular events than those with a native T1 Z-score ≥ 2.41 (log-rank P = 0.001). Moreover, such a low native T1 Z-score and more severe VFMR in an effective regurgitant orifice area (EROA) ≥ 0.30 cm2 was associated with fewer cardiovascular events than for a high native T1 Z-score of ≥ 2.41 and less severe VFMR of EROA < 0.30 cm2 (log-rank P = 0.002). Conclusion Assessment of baseline LV myocardial damage by means of native T1 Z-score obtained with CMR without the use of gadolinium-based contrast media is a valuable additional parameter for better management of symptomatic NICM patients with reduced LVEF and VFMR following TEER.

A five-year-old boy with anaphylaxis reaction to gadolinium-based MR contrast medium: a case report

Magnetic resonance imaging (MRI) is one of the most widely used tests in orthopedic areas. Gadolinium-based magnetic resonance (MR) contrast media are commonly used for MRI tests. They are known to be safe with little side effects and low incidence of acute adverse reactions. Although not common, immediate hypersensitivity reaction can occur in some patients after administration of gadolinium-based MR contrast media, causing skin rash, vascular edema, dyspnea, abdominal pain, hypotension, altered mental status, cardiopulmonary arrest, and even death. During a knee joint MRI test in a 5-year-old boy, anaphylaxis, a serious symptom, occured after injecting gadolinium-based MR contrast medium. Here we report this case along with a literature review.

Multisystem Imaging Manifestations of Kidney Failure.

Kidney failure (KF) refers to a progressive decline in glomerular filtration rate to below 15 ml/min per 1.73 m2, necessitating renal replacement therapy with dialysis or renal transplant. The hemodynamic and metabolic alterations in KF combined with a proinflammatory and coagulopathic state leads to complex multisystemic complications. The imaging hallmark of systemic manifestations of KF is bone resorption caused by secondary hyperparathyroidism. Other musculoskeletal complications include brown tumor, osteosclerosis, calcinosis, soft-tissue calcification, and amyloid arthropathy. Cardiovascular complications and infections are the leading causes of death in KF. Cardiovascular complications include accelerated atherosclerosis, cardiomyopathy, pericarditis, myocardial calcinosis, and venous thromboembolism. Neurologic complications such as encephalopathy, osmotic demyelination, cerebrovascular disease, and opportunistic infections are also frequently encountered. Pulmonary complications include edema and calcifications. Radiography and CT are used in assessing musculoskeletal and thoracic complications, while MRI plays a key role in assessing neurologic and cardiovascular complications. CT iodinated contrast material is generally avoided in patients with KF except in situations where the benefit of contrast-enhanced CT outweighs the risks and in patients already undergoing maintenance dialysis. At MRI, group II gadolinium-based contrast material can be safely administered in patients with KF. The authors discuss the extrarenal systemic manifestations of KF, the choice of imaging modality in their assessment, and imaging findings of complications. ©RSNA, 2024 Supplemental material is available for this article.

Contrast Media in Pregnant and Lactating Patients, From the AJR Special Series on Contrast Media.

IV contrast media improve the diagnostic power of radiology examinations. These media include gadolinium-based contrast media and iron-oxide nanoparticles for MRI, iodinated contrast material for CT, microbubbles for ultrasound, and radiopharmaceuticals for nuclear medicine. As for all medications, contrast media carry risks, which may be heightened in the conditions of pregnancy and lactation. Radiologists must understand the potential risks from contrast media exposure to the pregnant patient, fetus, and nursing infant, as well as understand these administrations' impact on examinations' clinical utility. This article reviews the available literature on these media, along with key regulatory bodies' and professional societies' current recommendations for their use, in the settings of pregnancy and lactation. This knowledge should help radiologists make well-reasoned risk-benefit analyses regarding contrast media administration and provide informed consent discussions with pregnant and nursing patients in whom contrast media administration is being considered. This information and analysis can also assist facilities in designing policies and standard operating procedures of possible clinical benefit to the pregnant patient, fetus, or nursing infant, balancing contrast media exposure considerations versus augmented diagnostic capabilities.

Influence of Gadolinium-based Contrast Media and Inter-reader Variation on the Estimation of Intravoxel Incoherent Motion (IVIM) Parameters in Breast MR Imaging.

Gadolinium-based contrast media (GBCM) may affect apparent diffusion coefficient measurements on diffusion-weighted imaging. We aimed at investigating the effect of GBCM and inter-reader variation on intravoxel incoherent motion (IVIM) parameters in breast lesions. A total of 89 patients referred to 3T breast MRI with at least one histologically verified lesion were included. IVIM data were acquired using a single-shot echo planar imaging sequence before and after GBCM administration. D (true diffusion coefficient), D* (pseudo-diffusion coefficient) and f (perfusion fraction) were calculated and measured by two readers (R1, R2). Inter-reader and intra-reader agreements were assessed by intraclass correlation coefficients (ICCs) and Bland-Altman plots. D was comparable before and after GBCM administration and between readers. D* and f decreased after GBCM administration and showed a lower agreement between readers. Intra-reader agreement before and after GBCM administration was almost perfect for D for both R1 and R2 (ICC 0.955 and 0.887). The intra-reader agreement was substantial to moderate for D* (ICC R1 0.708, R2 0.583) and moderate for f (ICC R1 0.529 and R2 0.425). Inter-reader agreement before GBCM administration was almost perfect for D (ICC 0.905), substantial for D* (ICC 0.733), and moderate for f (ICC 0.404); after contrast media administration, it was almost perfect for D (ICC 0.876) and substantial for D* (ICC 0.654) and f (ICC 0.606). Bland-Altman plots revealed no significant bias. Administration of GBCM seems to have a stronger effect on D* and f values than on D values. This should be considered when applying IVIM in clinical practice.

Evaluation of hafnium oxide nanoparticles imaging characteristics as a contrast agent in X-ray computed tomography.

This research aimed to compare the quantitative imaging attributes of synthesized hafnium oxide nanoparticles (NPs) derived from UiO-66-NH2(Hf) and two gadolinium- and iodine-based clinical contrast agents (CAs) using cylindrical phantom. Aqueous solutions of the studied CAs, containing 2.5, 5, and 10mg/mL of HfO2NPs, gadolinium, and iodine, were prepared. Constructed within a cylindrical phantom, 15cc small tubes were filled with CAs. Maintaining constant mAs, the phantom underwent scanning at tube voltage variations from 80 to 140 kVp. The CT numbers were quantified in Hounsfield units (HU), and the contrast-to-noise ratios (CNR) were calculated within delineated regions of interest (ROI) for all CAs. The HfO2NPs at 140 kVp and concentration of 2.5mg/ml exhibited 2.3- and 1.3-times higher CT numbers than iodine and gadolinium, respectively. Notably, gadolinium consistently displayed higher CT numbers than iodine across all exposure techniques and concentrations. At the highest tube potential, the maximum amount of the CAs CT numbers was attained, and at 140 kVp and concentration of 2.5mg/ml of HfO2NPs the CNR surpassed iodine by 114%, and gadolinium by 30%, respectively. HfO2NPs, as a contrast agent, demonstrated superior image quality in terms of contrast and noise in comparison to iodine- and gadolinium-based contrast media, particularly at higher energies of X-ray in computed tomography. Thus, its utilization is highly recommended in CT.

Efficacy of Native T1 Mapping for Patients With Non-Ischemic Cardiomyopathy and Ventricular Functional Mitral Regurgitation Undergoing Transcatheter Edge-to-Edge Repair.

We investigated the efficacy of left ventricular (LV) myocardial damage by native T1mapping obtained with cardiac magnetic resonance (CMR) for patients undergoing transcatheter edge-to-edge repair (TEER). We studied 40 symptomatic non-ischemic heart failure (HF) patients and ventricular functional mitral regurgitation (VFMR) undergoing TEER. LV myocardial damage was defined as the native T1Z-score, which was converted from native T1values obtained with CMR. The primary endpoint was defined as HF rehospitalization or cardiovascular death over 12 months after TEER. Multivariable Cox proportional hazards analysis showed that the native T1Z-score was the only independent parameter associated with cardiovascular events (hazard ratio 3.40; 95% confidential interval 1.51-7.67), and that patients with native T1Z-scores <2.41 experienced significantly fewer cardiovascular events than those with native T1Z-scores ≥2.41 (P=0.001). Moreover, the combination of a native T1Z-score <2.41 and more severe VFMR (effective regurgitant orifice area [EROA] ≥0.30 cm2) was associated with fewer cardiovascular events than a native T1Z-score ≥2.41 and less severe VFMR (EROA <0.30 cm2; P=0.002). Assessment of baseline LV myocardial damage based on native T1Z-scores obtained with CMR without gadolinium-based contrast media is a valuable additional parameter for better management of HF patients and VFMR following TEER.

MRI Gadolinium-Based Contrast Media: Meeting Radiological, Clinical, and Environmental Needs.

Gadolinium-based contrast agents (GBCAs) are routinely used in magnetic resonance imaging (MRI). They are essential for choosing the most appropriate medical or surgical strategy for patients with serious pathologies, particularly in oncologic, inflammatory, and cardiovascular diseases. However, GBCAs have been associated with an increased risk of nephrogenic systemic fibrosis in patients with renal failure, as well as the possibility of deposition in the brain, bones, and other organs, even in patients with normal renal function. Research is underway to reduce the quantity of gadolinium injected, without compromising image quality and diagnosis. The next generation of GBCAs will enable a reduction in the gadolinium dose administered. Gadopiclenol is the first of this new generation of GBCAs, with high relaxivity, thus having the potential to reduce the gadolinium dose while maintaining good in vivo stability due to its macrocyclic structure. High-stability and high-relaxivity GBCAs will be one of the solutions for reducing the dose of gadolinium to be administered in clinical practice, while the development of new technologies, including optimization of MRI acquisitions, new contrast mechanisms, and artificial intelligence may help reduce the need for GBCAs. Future solutions may involve a combination of next-generation GBCAs and image-processing techniques to optimize diagnosis and treatment planning while minimizing exposure to gadolinium. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY: Stage 3.

Single-Center Experience With Dynamic Contrast-Enhanced Magnetic Resonance Lymphangiography for Diagnosing Lymphatic Disorders and Guiding Percutaneous Embolization.

The pragmatic role of dynamic contrast-enhanced magnetic resonance lymphangiography (DCMRL) needs to be evaluated and compared across distinct lymphatic disorders. We aimed to evaluate the performance of DCMRL for identifying the underlying causes of lymphatic disorders and to define the potential benefit of DCMRL for planning lymphatic interventions. Patients who underwent DCMRL between August 2017 and July 2022 were included in this retrospective analysis. DCMRL was performed with intranodal injection of a gadolinium-based contrast medium through inguinal lymph nodes under local anesthesia. Technical success of DCMRL and feasibility of percutaneous embolization were assessed based on the lymphatic anatomy visualized by DCMRL. Based on the underlying causes, clinical outcomes were evaluated and compared. Seventy consecutive patients were included. The indications were traumatic chylothorax (n = 42), traumatic chylous ascites (n = 11), and nontraumatic lymphatic leak (n = 17). The technical success rate of DCMRL was the highest in association with nontraumatic lymphatic disorders (94.1% [16/17]), followed by traumatic chylothorax (92.9% [39/42]) and traumatic chylous ascites (81.8% [9/11]). Thirty-one (47.7%) patients among 65 patients who underwent technically successful DCMRL had feasible anatomy for intervention. Clinical success was achieved in 90.3% (28/31) of patients with feasible anatomy for radiologic intervention, while 62.5% (10/16) of patients with anatomical challenges showed improvement. Most patients with traumatic chylothorax showed improvement (92.9% [39/42]), whereas only 23.5% (4/17) of patients with nontraumatic lymphatic disorders showed clinical improvement. DCMRL can help identify the underlying causes of lymphatic disorders. The performance of DCMRL and clinical outcomes vary based on the underlying cause. The feasibility of lymphatic intervention can be determined using DCMRL, which can help in predicting clinical outcomes.

Gadolinium-Based Contrast Media Nephrotoxicity. Overview and Recommendations

Gadolinium-Based Contrast Media Nephrotoxicity. Overview and Recommendations

Hidden risk of gadolinium-based contrast agents during interventional pain medicine procedures: a retrospective chart review

IntroductionEpidural steroid injections and epidural blood patches commonly involve the injection of a small amount of radiocontrast media under fluoroscopy to properly identify the target tissue or anatomic space and...

A Survey of Practicing Radiologists on the Use of Premedication Before Intravenous Iodinated Contrast Medium Administration

ObjectiveTo determine whether updated guidance by the ACR in 2017 advocating use of intravenous (IV) premedication in emergency department (ED) patients and inpatients with reported iodinated contrast allergy was associated with a change in clinical practice. MethodsAn anonymous survey was distributed via e-mail in October 2020 to practicing radiologist members of the ACR interrogating use of corticosteroid premedication for two clinical vignettes: an indicated routine (perform within 24 hours) inpatient contrast-enhanced CT (CE-CT) and an indicated urgent (perform within 6 hours) ED CE-CT. In both scenarios, the patient had a prior moderate hypersensitivity reaction to iodinated contrast media. Clinical management was evaluated. Data were compared to historical controls from 2009. ResultsThe response rate was 11% (724 of 6,616). For the inpatient scenario, 72% (518 of 724) would use corticosteroid premedication with CE-CT, and 28% (200 of 724) would perform noncontrast CT. For the ED scenario, 67% (487 of 724) would use corticosteroid premedication with CE-CT, and 30% (217 of 724) would perform noncontrast CT. Oral premedication (85%, 439 of 518) was preferred for routine inpatients, and rapid IV premedication (89%, 433 of 487) was preferred for urgent ED patients. Of those who provided rapid IV dosing data in the ED, two doses of corticosteroids were used by 53% (216 of 410) and one dose was used by 45% (185 of 410), with academic radiologists more likely than private or hybrid practice radiologists to administer two doses (74% [74 of 100] versus 48% [151 of 312], P < .001, odds ratio, 3.03; 95% confidence interval, 1.84-5.00). Rapid IV premedication was more commonly used in 2020 than in 2009 (60% [433 of 724] versus 29% [20 of 69], P < .001, odds ratio, 3.65; 95% confidence interval, 2.12-6.26). Antihistamine use was common in both inpatient (93%, 480 of 518) and ED settings (92%, 447 of 487). Only 32% (229 of 721) of radiologists practiced in accordance with ACR guidelines, suggesting no need for routine premedication before CE-CT in patients with prior severe hypersensitivity reaction to gadolinium-based contrast media. Nonetheless, most (93%, 670 of 724) said the ACR Manual on Contrast Media was a major determinant of their practice. ConclusionsUse of rapid IV premedication in urgent settings has increased since 2009, following updated ACR guidelines, but there is disagreement over whether one or two corticosteroid doses is required. Despite reported high reliance on ACR guidelines, deviations from those guidelines remain common. In general, when ACR guidelines were not followed, it was in a risk-averse direction.

#4168 RISK FACTORS FOR POST-CONTRAST AKI IN PATIENTS MIXEDLY ADMINISTERED BOTH IODINE- AND GADOLINIUM-BASED CONTRAST MEDIA ON VISITING EMERGENCY ROOM

Abstract Background and Aims This study aimed to investigate the incidence of post-contrast acute kidney injury (PC-AKI) and its risk factor in patients administered iodine-based contrast media alone and mixed use of iodine-based contrast media and gadolinium-based contrast media. Method This retrospective study analyzed the data from 2016 to 2021. Patients who had end-stage of renal disease or missing data for estimating renal function were excluded. The primary outcome was the development of PC-AKI, i.e., an increase in creatinine of ≥25% or 0.5 mg/dL over the baseline or reduction in eGFR of ≥25% within 72 h. We compared the primary outcomes between the iodine-based contrast media alone and Mixed groups using a propensity score matching (PSM) analysis, and its risk factors were assessed from multivariable logistic regression. Results Of the 29,635 patients administrated iodine-based contrast media, 6,318 were included. There were 139 patients who mixedly administered iodine-based contrast media and GBCA. Mixed group showed significant higher rate of development of PC-AKI compared with iodine-based contrast media alone group in total cohort (adjusted OR, 3.09 [95% CI, 2.09 – 4.58]) and PSM cohort (adjusted OR, 2.38 [95% CI, 1.25 – 4.55]). On multivariate analysis to investigate risk factors in Mixed group, osmolality (adjusted aOR, 1.05 [95% CI, 1.01–1.10]) and eGFR (adjusted OR, 0.931; 95% CI, 0.883–0.983) were associated with PC-AKI. Conclusion Mixed administration of iodine-based contrast media and GBCA on same day at ED visit may be a risk factor for PC-AKI compared with single administration of iodine-based contrast media alone. Osmolality and eGFR may be independently associated with PC-AKI after mixed administration of iodine-based contrast media and GBCA

What you need to know about: imaging in patients with renal failure.

Contrast-enhanced medical imaging is commonly requested in clinical practice. Contrast media provide better differentiation of tissue enhancement, improves the soft tissue contrast resolution, and enhances the ability to study the physiology and function of the organs and/or systems. However, contrast media may cause complications, especially in patients with renal failure. This article discusses the use of contrast media in common imaging modalities and the relationship between contrast media and renal function. Administration of iodinated contrast media in computed tomography may cause contrast-associated acute kidney injury; the risk factors and preventive strategies for this are elaborated in this article. Administration of gadolinium-based contrast media in magnetic resonance imaging may lead to nephrogenic systemic fibrosis. Therefore, precautions should be taken when planning for medical imaging for patients with pre-existing acute kidney injury or end-stage chronic kidney disease, for whom contrast media administration in computed tomography or magnetic resonance imaging may be relatively contraindicated. Alternatively, ultrasound contrast agents can be safely used in patients with acute kidney injury or chronic kidney disease. Clinical teams should discuss these patients with radiologists, taking into account the risk-benefits of contrast media, to determine the optimal imaging protocol or modality to answer the clinical query.

Risk factors for post-contrast acute kidney injury in patients sequentially administered iodine- and gadolinium-based contrast media on the same visit to the emergency department: a retrospective study.

This study compares the incidence of post-contrast acute kidney injury (PC-AKI) in patients who received a single administration of iodine-based contrast medium (ICM) with that in patients who received a sequential administration of ICM and gadolinium- based contrast agents (GBCA) in a single visit to an emergency department (ED) to determine the risk factors for PC-AKI. Patients who received one or more contrast media in the ED from 2016 to 2021 were included in this retrospective study. They were divided into the ICM alone and ICM + GBCA groups, and the incidence of PC-AKI was compared between the groups. The risk factors were assessed using a multivariable analysis after propensity score matching (PSM). Overall, 6,318 patients were analyzed, of whom 139 were in the ICM + GBCA group. The incidence of PC-AKI was significantly higher in the ICM + GBCA group than in the ICM alone group (10.9% vs. 27.3%, p &lt; 0.001). In the multivariable analysis, sequential administration was a risk factor for PC-AKI, and single administration was not (adjusted odds ratio [95% confidence interval] in the 1:1, 2:1, and 3:1 PSM cohorts: 2.38 [1.25-4.55], 2.13 [1.26-3.60], and 2.28 [1.39-3.72], respectively). In subgroup analyses of the ICM + GBCA group, osmolality (1.05 [1.01-1.10]) and estimated glomerular filtration rate (eGFR, 0.93 [0.88-0.98]) were associated with PC-AKI. Compared with a single administration of ICM alone, sequential administration of ICM and GBCA during a single ED visit might be a risk factor for PC-AKI. Osmolality and eGFR might be associated with PC-AKI after sequential administration.

WCN23-1001 Risk factors for post-contrast acute kidney injury in patients mixedly administered both iodine- and gadolinium-based contrast media on the same visit to the emergency department

WCN23-1001 Risk factors for post-contrast acute kidney injury in patients mixedly administered both iodine- and gadolinium-based contrast media on the same visit to the emergency department

Can I Diagnose a Vestibular Schwannoma Using Non-Contrast Imaging?

&#x0D; &#x0D; &#x0D; &#x0D; “I have an adult patient with new-onset unilateral sensorineural hearing loss. I would like to rule out a vestibular schwannoma by performing an MRI exam. However, the patient has a kidney problem that prevents him from receiving contrast material. Can I still diagnose a vestibular schwannoma using a non-contrast imaging study?”&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; The answer to this question is ... YES! At the current time, gadolinium-enhanced T1-weighted magnetic resonance imaging (MRI) is considered the gold standard for the diagnosis of vestibular schwannomas.1 However, the use of gadolinium-based contrast material may be contraindicated in patients with impaired renal function, in those who have had an allergic reaction to such contrast material, and in patients who are or may be pregnant.&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; High-resolution T2-weighted MR sequences as a means of visualizing the fluid-filled inner ear and the 7th and 8th cranial nerves in the internal auditory canal and cerebellopontine angle cistern was described in the early 1990’s.2 These steady-state imaging sequences currently include various manufacturer-specific sequences such as CISS (Constructive Interference into Steady State, Siemens), FIESTA-C (Fast Imaging Employing Steady-state Acquisition Cycled Phases, GE), DRIVE (Driven Equilibrium Radiofrequency Reset Pulse, Philips), bFFE (Balanced Fast Field Echo, Philips) and SPACE (Sampling Perfection with Application optimized Contrasts using different flip angle Evolutions, Siemens).3 The submillimeter-resolution images from these sequences can be manipulated on computer-based DICOM imaging software to provide reformatted images in non-orthogonal planes that allow visualization of the entire 8th cranial nerve, from the brainstem to the fundus of the internal auditory canal. In these sequences, cerebrospinal fluid (CSF) displays a high signal intensity that provides an excellent contrasting background to the inherent low signal intensity of the 7th and 8th cranial nerves. (Figure 1)&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; Similar to the nerves, a vestibular schwannoma will appear as a low-intensity (dark) filling defect that may be nodular, oblong, or ice cream cone-shaped, and located in the internal auditory canal and/or the cerebellopontine angle cistern immediately adjacent to it. (Figure 2)&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; In evaluating a patient for the presence of a vestibular schwannoma, the current medical literature indicates that high-resolution T2- weighted imaging sequences have a high sensitivity and specificity compared to gadolinium-enhanced T1-weighted imaging. However, T2-weighted imaging alone may not detect inflammatory, infectious or malignant conditions that may also present with sensorineural hearing loss.1 As such, a gadolinium-enhanced T1-weighted sequence will be needed when such conditions are suspected.&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; Finally, local experience with institutions that perform imaging of the internal auditory canal and cerebellopontine angle shows that not all centers routinely perform the high-resolution T2-weighted imaging sequences. Therefore, it would be prudent to specifically indicate the need for “a T2-weighted imaging sequence with submillimeter- resolution, such as the CISS or FIESTA-C sequence” in the imaging request, in order to ensure the performance of the appropriate imaging strategy.&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D;

Contrast-Enhanced Three-Dimensional Fluid-Attenuated Inversion Recovery Imaging with an Optimal Scan Interval and Angulation to Visualize Endolymphatic Hydrops

Background: There is no gold standard diagnostic test for endolymphatic hydrops (EH). Three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) imaging has been reported to depict EH with administration of gadolinium-based contrast media (GBCM). However, the optimal scan interval and angulation remain unknown in 3D-FLAIR labyrinthine imaging following double-dose injections of a gadolinium-based contrast agent in patients with vertigo and sensorineural hearing loss. Objectives: This study aimed to determine the optimal parameters of 3D-FLAIR labyrinthine imaging, including the optimal scan angulation and scan interval, for patients with sensorineural hearing loss and vertigo. Patients and Methods: In this cross-sectional clinical study, following the double-dose administration of a gadolinium contrast agent, 3D-FLAIR labyrinthine images were acquired from 22 patients with unilateral vertigo and sensorineural hearing loss at different intervals after injection. The corresponding contrast-to-noise ratios (CNRs) and signal-intensity ratios (SIRs) of these images, acquired at different intervals, were measured. Moreover, separate visualization of endolymphatic and perilymphatic spaces was scored, and angulation of the anterior skull base scan was investigated in the sagittal position. Results: The 3D-FLAIR images showed the strongest image contrast in the cochlea with a double-dose gadolinium-based contrast injection at six hours post-injection. Significantly higher SIR and CNR values were reported at six hours post-injection in both unaffected and affected ears compared to other intervals (4 h vs. 6 h in the affected side, SIR: 1.65 ± 0.24 vs. 2.09 ± 0.47, CNR: 13.88 ± 5.54 vs. 19.17 ± 6.81; in the unaffected side, SIR: 1.58 ± 0.27 vs. 1.82 ± 0.34, CNR: 12.20 ± 3.88 vs. 15.42 ± 4.58, P &lt; 0.001 for all; 6 h vs. 8 h in the affected side: SIR: 2.09 ± 0.47 vs. 1.72 ± 0.43, CNR: 19.17 ± 6.81 vs. 12.22 ± 4.96; in the unaffected side, SIR: 1.82 ± 0.34 vs. 1.57 ± 0.30, CNR: 15.42 ± 4.58 vs. 10.61 ± 3.87, P &lt; 0.001 for all). Visualization of the endo- and perilymphatic spaces for both the cochlea and vestibule was significantly better at six hours post-injection compared to four hours post-injection in both affected sides (P &lt; 0.05 for both). The optimal angulation ranged from 6.20° to 13.6° (P &lt; 0.001). Conclusion: By using an optimal scan interval, together with an optimal scan angulation, 3D-FLAIR imaging can reliably visualize the endolymphatic space and sensitively indicate cochlear blood-labyrinth barrier disruptions without requiring extra image reconstruction.

The feasibility of superparamagnetic iron oxide-enhanced magnetic resonance imaging for assessing liver lesions in patients with contraindications for iodine CT contrast media or gadolinium-based MR contrast media: a retrospective case-control study.

BackgroundThe detection and characterization of liver lesions are problematic in patients with bronchial asthma, renal dysfunction, or a history of allergy to gadolinium-based magnetic resonance contrast media or iodine-computed tomography contrast media because these contrast media cannot be used. Hence, the information on the lesion vascularity cannot be obtained. Therefore, this retrospective case-control study evaluated the feasibility of superparamagnetic iron oxide (SPIO) in patients with one or more of these contraindications who underwent SPIO-enhanced magnetic resonance imaging for the assessment of liver lesions.MethodsTwenty-six patients with a total of 48 lesions were analyzed. SPIO was used in the case of all patients because each patient had at least one reason not to use iodine contrast or gadolinium-based contrast media. Additionally, all patients were subjected to the perfusion study. A total volume of 1.3 mL of SPIO was injected via the cubital vein at a rate of 3 mL per second, followed by 40 mL saline at the same speed. The scanning of the perfusion study was started 4 s after the beginning of superparamagnetic iron oxide injection and scanning took 50 s. Two radiologists independently evaluated whether the lesion was malignant or benign. Receiver operating characteristic analysis (ROC) was performed to determine the additional benefit of the perfusion study.ResultsThere were no adverse effects associated with SPIO. The area under the curve (AUC) value without perfusion study for observers 1 and 2 were 0.473 (P=0.794, 95% CI: 0.275–0.672) and 0.602 (P=0.305, 95% CI: 0.407–0.798), respectively, whereas the Az values with perfusion study for observers 1 and 2 were 0.782 (P=0.011, 95% CI: 0.565–0.998) and 0.784 (P=0.004, 95% CI: 0.591–0.977), respectively. Az value became significantly better when the perfusion study has added (P=0.001 and 0.012 by observers 1 and 2).ConclusionsSPIO can be used safely in patients with bronchial asthma, renal dysfunction, or a history of contrast media allergy. Furthermore, the diagnostic accuracy of SPIO was acceptable.