Administration Of Gadolinium-based Contrast Media Research Articles

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.

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 < 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 < 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 < 0.05 for both). The optimal angulation ranged from 6.20° to 13.6° (P < 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.

A retrospective cohort evaluation of the effect of multiple administrations of gadopentetate dimeglumine on brain magnetic resonance imaging T1-weighted signal.

Gadolinium deposition occurs following repeated administration of gadolinium-based contrast media. However, few studies have evaluated factors that lead to increased detection of deposition or the individual differences among patients. To measure the effect of repeated dosages of gadopentetate dimeglumine on pediatric brains and to determine the factors that influence signal intensity changes. A retrospective study evaluated magnetic resonance imaging (MRI) in patients <18years of age who received >5 doses of gadopentetate dimeglumine. Regions of interest were placed in 30 locations in the brain on axial precontrast T1 images. Signal intensity ratios were evaluated throughout the brain. The effect of increasing gadopentetate dimeglumine exposure on signal intensity ratios was assessed using linear mixed models adjusted for gender, age, imaging sequence type (fast spin echo or gradient echo), MRI manufacturer (General Electric, Philips or Siemens), and field strength (1.5 tesla [T] or 3T). Finally, the variance of the random slope in the linear mixed models was tested to determine if there were differences in the rate of signal intensity ratio change among individuals. Fifty patients (M:F=25:25; mean age at first imaging: 6.4years) with a mean of 21.5 gadopentetate dimeglumine administrations (range: 6-86) were included. There were significant increases in T1 signal in the globus pallidus, dentate nucleus and pulvinar with an increasing number of contrast administrations. Patient gender, age, and MRI field strength were not associated with changing signal intensity ratios. However, MRI sequence type and vendor significantly impacted some measured signal intensity ratios. Finally, significant differences in the slopes of the ratios were present among patients for multiple locations. Repeated administration of gadopentetate dimeglumine is associated with T1 hyperintense signal in the dentate nucleus, globus pallidus and pulvinar. Detection is significantly affected by MRI sequence type and scanner vendor. Even when accounting for these differences, there are individual differences in the slope of signal intensity change suggesting a patient-level effect influences gadolinium deposition.

Hiatal hernias in patients with GERD-like symptoms: evaluation of dynamic real-time MRI vs endoscopy.

To assess the diagnostic potential of real-time MRI for assessment of hiatal hernias in patients with GERD-like symptoms compared to endoscopy. One hundred eight patients with GERD-like symptoms were included in this observational cohort study between 2015 and 2017. Real-time MRI was performed at 3.0 Tesla with temporal resolution of 40ms, dynamically visualizing the esophageal transport of a pineapple juice bolus, its passage through the gastroesophageal junction, and functional responses during Valsalva maneuver. Hernia detection on MRI and endoscopy was calculated using contingency tables with diagnosis of hernia on either modality as reference. Of 108 patients, 107 underwent successful MRI without adverse events; 1 examination was aborted to inability to swallow pineapple juice in supine position. No perforation or acute bleeding occurred during endoscopy. Median examination time was 15min. Eighty-five patients (79.4%) were diagnosed with hiatal hernia on either real-time MRI or endoscopy. Forty-six hernias were visible on both modalities. Seventeen hernias were evident exclusively on MRI, and 22 exclusively on endoscopy. Sixteen of the 63 MRI-detected hernias (25.4%) were detectable only during Valsalva maneuver, which were smaller compared to hernias at rest (median - 13.5 vs - 33.0mm, p < 0.001). Diagnostic accuracy for hernia detection was comparable for MRI and endoscopy (sensitivity 74% vs 80%, p = 0.4223; specificity 100% vs 100%, p > 0.99). Real-time MRI is a fast and safe modality for assessment of the gastroesophageal junction, without radiation exposure or administration of gadolinium-based contrast media. Although MRI and endoscopy yield comparable diagnostic accuracy, dynamic MRI sequences are able to visualize hiatal hernias that were occult on static MRI sequences or endoscopy in a relevant number of cases. • Real-time MRI is a safe and fast imaging modality for examination of the gastroesophageal junction, combining anatomical and functional information for enhanced detection of hiatal hernias. • Real-time MRI and endoscopy yield comparably high diagnostic accuracy: real-time MRI visualizes hiatal hernias that were occult on endoscopy in a relevant number of patients; however, several hiatal hernias detected on endoscopy were occult on real-time MRI. • There is clinical potential of real-time MR imaging in patients with GERD-like symptoms and equivocal findings on endoscopy or pH-metry, for anatomical visualization in patients planned for surgical intervention, or those with suspected fundoplication failures.

High-Signal Bladder Urine at T1-Weighted MR Imaging Performed 1-7 Days After a Prior Gadolinium-Enhanced MRI: Prevalence and Correlation with Renal Function.

Objective:To determine the prevalence of high-signal bladder urine at T 1 weighted MRI performed 1–7 days after injection of gadolinium-based contrast material and to assess for correlation with altered renal function.Methods:The study group consisted of 267 patients who underwent MRI that included the bladder 1–7 days after a prior gadolinium-enhanced MRI. A control group consisted of 200 patients who underwent pelvic MRI and had not received gadolinium-based contrast material within the prior month. One reader recorded the relative T 1 weighted signal intensity of bladder urine and calculated the estimated glomerular filtration rate (eGFR) for each patient. A positive scan was defined as one with bladder urine T 1 weighted signal higher than that of muscle.Results:25 (9%) of 267 study group scans were positive; this included 68% ( n = 19) of scans obtained 12–24 h after gadolinium-based contrast material administration, 21% ( n = 3) after 25–36 h, 7% ( n = 2) after 37–48 h, and 3% ( n = 1) after 49–72 h. No positive scan occurred after 72 h or in the control group. Mean eGFR in positive scans obtained more than 36 h after gadolinium-based contrast material administration was significantly lower than in negative scans in the same timeframe (37 vs 76 ml/min, respectively; p = 0.01).Conclusion:High T 1 weighted signal in bladder urine occasionally is present on MRI performed up to 3 days after gadolinium-based contrast material administration, presumably reflecting residual excreted gadolinium-based contrast material. When visible more than 36 hours after gadolinium-based contrast material administration, such increased signal is associated with low eGFR.Advances in knowledge:Increased signal is occasionally present in bladder urine at MRI performed up to 3 days after gadolinium-based contrast material administration. When higher signal is visible more than 36 hours after contrast administration, it is associated with decreased eGFR.

Real-time MRI for the dynamic assessment of fundoplication failure in patients with gastroesophageal reflux disease.

To assess the diagnostic potential of dynamic real-time MRI for fundoplication failure in patients with persistent or recurrent GERD-like (gastroesophageal reflux disease) complaints. Twenty-two consecutive patients (male n = 11; female n = 11; median age 59years) with recurrent or persistent GERD-like symptom after fundoplication were enrolled between 2015 and 2017. Median duration of GERD-like symptoms was 21months. Real-time MRI (3 Tesla) was performed at 40ms temporal resolution using undersampled radial fast low-angle shot acquisitions with nonlinear inverse image reconstruction. MRI movies dynamically visualized bolus transit of pineapple juice through the gastroesophageal junction, position of the fundoplication wrap and recurring hernia or reflux during Valsalva maneuver. MRI results were compared to endoscopic findings. Real-time MRI was successfully completed in all patients without adverse events (average examination time 15min). Morphological correlates for GERD-like symptoms were evident in 20 patients (90.1%) with gastric reflux in 19 cases. Nine patients (40.1%) had wrap disruption and recurrent gastric hernia. Wrap migration or telescoping hernia was detected in nine patients (40.1%). One patient presented with continued reflux despite intact fundoplication wrap. Esophageal dysmotility with delayed bolus passage was observed in one case. On endoscopy, gastric hernia or wrap disruption was diagnosed in seven cases, and esophagitis or Barret's metaplasia in nine cases. Real-time MRI is a fast and safe modality for dynamic imaging after fundoplication, without radiation exposure or administration of gadolinium-based contrast media. In a relevant number of cases, real-time MRI reveals correlates for GERD-like symptoms. • Real-time MRI reliably visualizes the gastroesophageal junction after fundoplication surgery. • Patients with recurring GERD-like symptoms have a high rate of morphological failure patterns that can be identified by real-time MRI. • Dynamic assessment of gastroesophageal junction by real-time MRI is a perspective diagnostic tool for detection of fundoplication failure.

MR ENTEROGRAPHY: AN EMERGENT TECHNIQUE FOR CHARACTERIZATION OF SMALL BOWEL LESIONS IN ONCOLOGICAL AND NON-ONCOLOGY DISEASES

Small bowel is not easily accessed by endoscope and diagnosis of its pathology relies on clinical assessment and imaging. Traditional contrast studies have the disadvantage of not including the mural and extramural details. This is best seen with magnetic resonance enterography (MRE) which is rapidly replacing computed tomography enterography due to better soft tissue resolution and lack of ionizing radiation. Comprehensive MRE requires axial and coronal T1- and T2-WI, high-resolution diffusion-weighted images, fat-suppressed three-dimensional T1-W breath-hold gradient-echo images of the abdomen, and pelvis before and after intravenous gadolinium-based contrast material administration. MRE is the preferred imaging technique for small bowel pathology due to its ability to show mural and extramural details which allow differentiation in acute, active, and chronicity of changes. Being radiation free, there is no age limitation for its use.

Gadolinium-based Contrast Media, Cerebrospinal Fluid and the Glymphatic System: Possible Mechanisms for the Deposition of Gadolinium in the Brain.

After Kanda’s first report in 2014 on gadolinium (Gd) deposition in brain tissue, a considerable number of studies have investigated the explanation for the observation. Gd deposition in brain tissue after repeated administration of gadolinium-based contrast medium (GBCM) has been histologically proven, and chelate stability has been shown to affect the deposition. However, the mechanism for this deposition has not been fully elucidated. Recently, a hypothesis was introduced that involves the ‘glymphatic system’, which is a coined word that combines ‘gl’ for glia cell and ‘lymphatic’ system. According to this hypothesis, the perivascular space functions as a conduit for cerebrospinal fluid to flow into the brain parenchyma. The perivascular space around the arteries allows cerebrospinal fluid to enter the interstitial space of the brain tissue through water channels controlled by aquaporin 4. The cerebrospinal fluid entering the interstitial space clears waste proteins from the tissue. It then flows into the perivascular space around the vein and is discharged outside the brain. In addition to the hypothesis regarding the glymphatic system, some reports have described that after GBCM administration, some of the GBCM distributes through systemic blood circulation and remains in other compartments including the cerebrospinal fluid. It is thought that the GBCM distributed into the cerebrospinal fluid cavity via the glymphatic system may remain in brain tissue for a longer duration compared to the GBCM in systemic circulation. Glymphatic system may of course act as a clearance system for GBCM from brain tissue. Based on these findings, the mechanism for Gd deposition in the brain will be discussed in this review. The authors speculate that the glymphatic system may be the major contributory factor to the deposition and clearance of gadolinium in brain tissue.

Heterotopic Pancreas: Histopathologic Features, Imaging Findings, and Complications.

Heterotopic pancreas is a congenital anomaly in which pancreatic tissue is anatomically separate from the main gland. The most common locations of this displacement include the upper gastrointestinal tract-specifically, the stomach, duodenum, and proximal jejunum. Less common sites are the esophagus, ileum, Meckel diverticulum, biliary tree, mesentery, and spleen. Uncomplicated heterotopic pancreas is typically asymptomatic, with the lesion being discovered incidentally during an unrelated surgery, during an imaging examination, or at autopsy. The most common computed tomographic appearance of heterotopic pancreas is that of a small oval intramural mass with microlobulated margins and an endoluminal growth pattern. The attenuation and enhancement characteristics of these lesions parallel their histologic composition. Acinus-dominant lesions demonstrate avid homogeneous enhancement after intravenous contrast material administration, whereas duct-dominant lesions are hypovascular and heterogeneous. At magnetic resonance imaging, the heterotopic pancreas is isointense to the orthotopic pancreas, with characteristic T1 hyperintensity and early avid enhancement after intravenous gadolinium-based contrast material administration. Heterotopic pancreatic tissue has a rudimentary ductal system in which an orifice is sometimes visible at imaging as a central umbilication of the lesion. Complications of heterotopic pancreas include pancreatitis, pseudocyst formation, malignant degeneration, gastrointestinal bleeding, bowel obstruction, and intussusception. Certain complications may be erroneously diagnosed as malignancy. Paraduodenal pancreatitis is thought to be due to cystic degeneration of heterotopic pancreatic tissue in the medial wall of the duodenum. Recognizing the characteristic imaging features of heterotopic pancreas aids in differentiating it from cancer and thus in avoiding unnecessary surgery. © RSNA, 2017.

Contrast-enhanced magnetic resonance pancreatography with gadoteridol by heavily T2-weighted three-dimensional fluid-attenuated inversion recovery: preliminary results in healthy subjects.

The purpose of this study was to investigate the feasibility of contrast-enhanced magnetic resonance (MR) pancreatography with intravenously administered gadolinium-based contrast material (GBCM) in healthy subjects. Eight healthy male subjects (age: 29-53 years old, median: 37 years old) were enrolled. Contrast-enhanced MR pancreatography was scanned with heavily T2-weighted three-dimensional fluid-attenuated inversion recovery (hT2W-3D-FLAIR) before and after intravenous GBCM administration. Two radiologists evaluated the images, referring to three-dimensional MR pancreatography by consensus. Scanning was performed five times at 1.5-h intervals (at 0.5, 2, 3.5, 5, and 6.5 h) after GBCM administration. In all subjects, pre-contrast-enhanced hT2W-3D-FLAIR images demonstrated no visualization of the main pancreatic duct. After GBCM administration, the main pancreatic duct was visualized in all subjects at 0.5 h (n=4, 50%) and/or 2 h (n=7, 88%). The mean signal intensity of the main pancreatic duct was 3.17 ± 0.78 at pre-contrast enhancement, 7.96 ± 4.60 at 0.5 h, and 8.08 ± 4.64 at 2 h. The signal intensity ratio of the main pancreatic duct against the pancreatic parenchyma was statistically higher (P < 0.01) at the 0.5-h and 2-h scans than that of pre-contrast-enhanced scan. Intravenously administered GBCM seeped into the pancreatic duct in sufficient concentration to alter the appearance of the main pancreatic duct by hT2W-3D-FLAIR in healthy subjects.

Novel cardiac magnetic resonance biomarkers: native T1 and extracellular volume myocardial mapping.

Cardiac magnetic resonance (CMR) is a non-invasive diagnostic tool playing a key role in the assessment of cardiac morphology and function as well as in tissue characterization. Late gadolinium enhancement is a fundamental CMR technique for detecting focal or regional abnormalities such as scar tissue, replacement fibrosis, or inflammation using qualitative, semi-quantitative, or quantitative methods, but not allowing for evaluating the whole myocardium in the presence of diffuse disease. The novel T1 mapping approach permits a quantitative assessment of the entire myocardium providing a voxel-by-voxel map of native T1 relaxation time, obtained before the intravenous administration of gadolinium-based contrast material. Combining T1 data obtained before and after contrast injection, it is also possible to calculate the voxel-by-voxel extracellular volume (ECV), resulting in another myocardial parametric map. This article describes technical challenges and clinical perspectives of these two novel CMR biomarkers: myocardial native T1 and ECV mapping.

Ratio of Vestibular Endolymph in Patients with Isolated Lateral Semicircular Canal Dysplasia.

Isolated vestibular-lateral semicircular canal dysplasia (LSCCD) is one of the most common anomalies of the inner ear. However, endolymphatic size in LSCCD is unknown. We measured the size of the endolymph in the vestibule of patients with LSCCD and compared it with that measured in patients without LSCCD. We extracted 1102 magnetic resonance (MR) studies for the evaluation of endolymphatic hydrops (EH) from our database of radiology reports. Among these, we found 15 ears from 11 patients with LSCCD; 4 patients had bilateral abnormalities. Seven of the 15 ears demonstrated aplasia and 8 ears, hypoplasia of the lateral semicircular canal (LSCC). The control group consisted of 26 ears from 13 randomly selected patients without LSCCD. We measured the area of endolymph in the vestibule (ELA), total area of vestibular lymph fluid (TLA), and area of the central bony island (CBI) of the LSCC from axial MR images obtained after intratympanic or intravenous administration of gadolinium-based contrast material. The ratio of endolymphatic area to total lymphatic area (%EL) was defined as %EL = ELA/TLA × 100.We evaluated the correlation between %EL and the area of the CBI and compared age, %EL, degree of cochlear EH, hearing level, and presence of rotating vertigo among the 3 groups (aplasia, hypoplasia, control). The mean %EL was 76.7% in the aplasia group, 50.0% in the hypoplasia group, and 27.8% in the control group (P < 0.001). There was a relatively strong linear correlation between the area of the CBI and %EL (r = -0.767). Patient age, mean hearing level, degree of cochlear EH, or presence of vertigo attacks did not differ significantly among the groups (P > 0.05). The size of vestibular endolymph was larger in the groups with aplasia or hypoplasia than the control group. Thus, the current diagnostic cut-off value for significant vestibular EH (>50%) might not be appropriate for ears with LSCCD.

Exclusion of a Brain Lesion: Is Intravenous Contrast Administration Required after Normal Precontrast Magnetic Resonance Imaging?

BackgroundNo evidence‐based guidelines are available for the administration of gadolinium‐based contrast media to veterinary patients.ObjectiveTo investigate whether administration of intravenous (IV) contrast media alters the likelihood of identifying a brain lesion in dogs and cats.AnimalsFour hundred and eighty‐seven client‐owned animals referred for investigation of intracranial disease.MethodsTwo reviewers retrospectively analyzed precontrast transverse and sagittal T1‐weighted (T1W), T2‐weighted, and fluid‐attenuated inversion recovery low‐field MRI sequences from each patient for the presence of a clinically relevant brain lesion. All sequences subsequently were reviewed in the same manner with additional access to postcontrast T1W images.ResultsOf the 487 precontrast MRI studies, 312 were judged to be normal by 1 or both reviewers. Of these 312 studies, a previously undetected lesion was identified in only 6 cases (1.9%) based on changes observed on postcontrast sequences. Final diagnoses included meningoencephalitis of unknown origin (n = 1), feline infectious peritonitis (n = 1), and neoplasia (n = 2). All 4 of these cases had persistent neurological deficits suggestive of an underlying brain lesion. Contrast enhancement observed in the 2 other cases was considered falsely positive based on the results of further investigations.Conclusions and Clinical ImportanceIn patients with normal neurological examination and normal precontrast MRI, the subsequent administration of IV gadolinium‐based contrast media is highly unlikely to disclose a previously unidentified lesion, calling into question the routine administration of contrast media to these patients. However, administration still should be considered in animals with persistent neurological deficits suggestive of an underlying inflammatory or neoplastic brain lesion.

Renal function, nephrogenic systemic fibrosis and other adverse reactions associated with gadolinium-based contrast media.

Nephrogenic systemic fibrosis is a fibrosing disorder that affects patients with impaired renal function and is associated with the administration of gadolinium-based contrast media used in MRI. Despite being in a group of drugs that were considered safe, report about this potentially serious adverse reaction was a turning point in the administration guidelines of these contrast media. There has been an attempt to establish safety parameters to identify patients with risk factors of renal failure. The close pharmacovigilance and strict observation of current regulations, with special attention being paid to the value of glomerular filtration, have reduced the published cases involving the use of gadolinium-based contrast media. In a meeting between radiologists and nephrologists we reviewed the most relevant aspects currently and recommendations for its prevention.

High Signal Intensity in the Dentate Nucleus and Globus Pallidus on Unenhanced T1-weighted MR Images: Relationship with Increasing Cumulative Dose of a Gadolinium-based Contrast Material

To explore any correlation between the number of previous gadolinium-based contrast material administrations and high signal intensity (SI) in the dentate nucleus and globus pallidus on unenhanced T1-weighted magnetic resonance (MR) images. The institutional review board approved this study, waiving the requirement to obtain written informed consent. A group of 381 consecutive patients who had undergone brain MR imaging was identified for cross-sectional analysis. For longitudinal analysis, 19 patients who had undergone at least six contrast-enhanced examinations were compared with 16 patients who had undergone at least six unenhanced examinations. The mean SIs of the dentate nucleus, pons, globus pallidus, and thalamus were measured on unenhanced T1-weighted images. The dentate nucleus-to-pons SI ratio was calculated by dividing the SI in the dentate nucleus by that in the pons, and the globus pallidus-to-thalamus SI ratio was calculated by dividing the SI in the globus pallidus by that in the thalamus. Stepwise regression analysis was undertaken in the consecutive patient group to detect any relationship between the dentate nucleus-to-pons or globus pallidus-to-thalamus SI ratio and previous gadolinium-based contrast material administration or other factors. A random coefficient model was used to evaluate for longitudinal analysis. The dentate nucleus-to-pons SI ratio showed a significant correlation with the number of previous gadolinium-based contrast material administrations (P < .001; regression coefficient, 0.010; 95% confidence interval [CI]: 0.009, 0.011; standardized regression coefficient, 0.695). The globus pallidus-to-thalamus SI ratio showed a significant correlation with the number of previous gadolinium-based contrast material administrations (P < .001; regression coefficient, 0.004; 95% CI: 0.002, 0.006; standardized regression coefficient, 0.288), radiation therapy (P = .009; regression coefficient, -0.014; 95% CI: -0.025, -0.004; standardized regression coefficient, -0.151), and liver function (P = .031; regression coefficient, 0.023; 95% CI: 0.002, 0.044; standardized regression coefficient, 0.107). The dentate nucleus-to-pons and globus pallidus-to-thalamus SI ratios in patients who had undergone contrast-enhanced examinations were significantly greater than those of patients who had undergone unenhanced examinations (P < .001 for both). High SI in the dentate nucleus and globus pallidus on unenhanced T1-weighted images may be a consequence of the number of previous gadolinium-based contrast material administrations.

Clinical applications of high-resolution ocular magnetic resonance imaging

Magnetic resonance imaging (MRI) using fast sequences with subjects staring at a target can provide motion-free ocular images, and small receiver surface coils make it possible to produce ocular images with high spatial resolution. MRI using half-Fourier single-shot rapid acquisition with a relaxation enhancement sequence as a fast T2-weighted imaging yields useful images for the morphologic diagnosis of ocular diseases, and MRI using a fast spoiled gradient-recalled-echo sequence as a T1-weighted imaging yields additional information by the administration of gadolinium-based contrast material for assessing the vascularity of intraocular tumors. These ocular imaging techniques are useful for the evaluation of patients with angle closure glaucoma, congenital abnormality of ocular globes, intraocular tumors and several types of detachments, as well as patients after ocular surgery. In this pictorial essay, we demonstrate the clinical applications of fast high-resolution ocular MRI with fixation of the subjects' visual foci.

Incidence of nephrogenic systemic fibrosis at a large university hospital in Sweden

Nephrogenic systemic fibrosis (NSF) is a rare condition that may follow administration of gadolinium-based contrast media (Gd-CM) in patients with renal insufficiency. This study was initiated to determine the incidence of NSF at Skåne University Hospital, Malmö, in Sweden. During the period January 2001 to December 2008 10 650 patients underwent magnetic resonance imaging (MRI) examinations. The re-expressed four-variable Modification of Diet in Renal Disease (MDRD) equation was used to calculate the estimated glomerular filtration rate (eGFR). The 272 patients with an eGFR <30 ml/min/1.73 m2 who were given Gd-CM were selected for final analysis. A diagnosis of NSF or other dermatological diagnoses in the 272 patients was searched for in the database of the Departments of Dermatology and Pathology. The 272 patients, of whom 26 patients were on dialysis, had undergone 406 MRI examinations with Gd-CM. Mean follow-up time was 3.9 (±2.7 SD) years. Assuming a mean body weight of 70 kg, the overall median dose of the 406 examinations with Gd-CM was 0.14 mmol/kg body weight (0.06, 0.34; 2.5-97.5 percentiles). In this retrospective study of patients with eGFR <30 ml/min/1.73 m(2), none developed NSF (the upper 95% confidence limit for zero cases of NSF in the 272 patients was 2.3%). Although it is premature to claim that Gd-CM using the regimen employed in this institution is safe to use in all patients with eGFR <30 ml/min/1.73 m(2), the results.indicate that development of NSF is extremely uncommon.

Risk of Acute Kidney Injury after Exposure to Gadolinium-Based Contrast in Patients with Renal Impairment

Objectives: Gadolinium-based contrast media (Gd-CM) are reported to induce acute kidney injury (AKI) in a high-risk population group at the usual dose for magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) examinations. We assessed gadolinium-induced nephropathy in patients with renal impairment who underwent MRI or MRA examinations, and evaluated the risk factors. Materials and methods: In this retrospective study, 238 patients with baseline renal impairment, who received MRI or MRA examinations with Gd-CM, were recruited. After all other AKI causes—liver decompensation, severe heart failure, all kinds of shock, and severe sepsis—and patients on dialysis were excluded, 158 patients were enrolled. AKI was defined as a decrease in glomerular filtration rate (GFR) >10% of baseline data within 3 days after administration of Gd-CM. Regression analysis was used to find independent risk factors for gadolinium-induced AKI (Gd-AKI). Results: Twenty-six of the 158 patients (16.5%) developed Gd-AKI. There were no significant differences in gender, age, or baseline GFR between those who did and who did not develop AKI. Comorbid coronary artery disease, liver cirrhosis, diabetes mellitus, and hypertension were not significantly associated with the development of Gd-AKI. However, sepsis was an independent risk factor for Gd-AKI after multivariate regression analysis (adjusted odds ratio: 4.417; 95% confidence interval: 1.671–11.676, p = 0.03). Conclusions: It is potential AKI after administration of Gd-CM under sepsis condition at the dose for MRI and MRA examinations in patients with renal impairment. It is important to identify high-risk patients and closely monitor renal function after administration of Gd-CM.

A Survey on the Use of Premedication Prior to Iodinated and Gadolinium-Based Contrast Material Administration

The aim of this study was to assess Society of Uroradiology member use of premedication before the intravenous administration of low-osmolality iodinated contrast materials (LOCM) and gadolinium-based contrast materials (GBCM). Society of Uroradiology members were invited to complete a Web-based survey concerning the use of premedication. The survey included scenarios concerning intravenous LOCM or GBCM injection in which respondents were asked whether they would recommend premedication or withhold contrast material injection. Results for LOCM questions were compared with those for GBCM questions. Question responses for LOCM were also compared with those from a similar Society of Uroradiology survey published in 1995. Sixty-two of 72 respondents (86%) used standardized premedication regimens. Fifty-nine of 61 described regimens (97%) included oral corticosteroids and 48 (79%) antihistamines. Twenty of 69 respondents (29%) had separate urgent premedication regimens. There was general agreement concerning premedication use; however, responses were inconsistent in patients with severe food or medication allergies, severe symptomatic asthma, or prior mild urticarial reactions. More respondents recommended premedication before LOCM than GBCM administration. More respondents recommended premedication or avoidance of contrast material injection in patients with prior contrast reactions in the current study compared with the 1995 study. There is frequent agreement among uroradiologists concerning the use of corticosteroid prophylaxis, but there is inconsistency in some clinical situations. The threshold for premedication is often lower for LOCM than GBCM. Since 1995, recommendations for use of premedication have become more widespread.

Techniken der kontrastmittelfreien MR-Angiografie

Especially in regard to the potential risks for the development of nephrogenic systemic fibrosis (NSF) following the administration of Gadolinium-based contrast material, nonenhanced MR angiography (MRA) methods are becoming ever more important. Besides well-established time-of-flight (TOF) and phase-contrast (PC) MRA, alternative imaging techniques based on balanced steady-state free precession (bSSFP) and turbo-spin-echo (TSE) sequences are increasingly used in combination with or without arterial spin labeling (ASL) strategies. This article provides an overview of the principles and clinical values of different nonenhanced MRA techniques. In addition, recent nonenhanced MRA developments are presented.