Bilateral Sustained Nephrograms After Parenteral Administration of Iodinated Contrast Material: A Potential Biomarker for Acute Kidney Injury, Dialysis, and Mortality.

OBJECTIVE: To determine whether persistent bilateral global nephrograms are associated with acute kidney injury (AKI), dialysis, and mortality. PATIENTS AND METHODS: All patients who underwent (1) contrast-enhanced computed tomography (CT) or cardiac catheterization with iohexol between January 1, 2000, and December 31, 2014, and (2) noncontrast abdominal CT in the subsequent 24±6 hours were identified. Patients without preprocedure and postprocedure creatinine measurements or who received additional contrast material were excluded. Nephrograms were identified by radiologist review and CT attenuation measurements. Univariate and multivariate analyses were performed to determine nephrogram risk factors. Acute kidney injury (defined as a creatinine level of ≥0.5 mg/dL or Kidney Disease: Improving Global Outcomes stages 1-3), dialysis, and mortality proportions were compared between patients with and without bilateral global nephrograms using the Fisher's exact test. RESULTS: A total of 123 patients met all inclusion criteria. The proportion of patients with a nephrogram was 37.4% (n=46), with a higher proportion following interventional (67% [18 of 30]) vs diagnostic (27.3% [9 of 33]) catheterization or contrast-enhanced computed tomography (31.7% [19 of 60]). Age (P=.002), chronic kidney disease (P=.05), and acute hypotension or shock (P=.02) were significant risk factors for nephrogram development. Patients with nephrogram had significantly higher rates of AKI (37.0% [17 of 46] vs 5.2% [4 of 77]; odds ratio [OR], 10.7 [95% CI, 3.31-34.5]; P<.001), dialysis (17.4% [8 of 46] vs 1.3% [1 of 77]; OR, 16.0 [95% CI, 1.93-133]; P=.001), and mortality (15.2% [7 of 46] vs 1.3% [1 of 77]; OR, 13.6 [1.62-115]; P=.003) than patients without nephrogram. CONCLUSION: The presence of persistent bilateral global nephrograms suggests an increased risk of AKI, dialysis, and mortality when compared with patients whose kidneys fully eliminated the contrast material.

Pilot Study to Show the Feasibility of High-Resolution Sagittal Ultrasound Imaging of the Temporomandibular Joint.

PURPOSE: To show the feasibility of acquiring high-resolution sagittal ultrasound (US) images of the temporomandibular joint (TMJ). PATIENTS AND METHODS: We used commercially available US probes to assess the TMJ via a transoral soft tissue window to acquire sagittal images. Magnetic resonance imaging and clinical correlation were compared with the US findings by the consensus assessment of 2 of the senior investigators. RESULTS: The sample was composed of 10 TMJs (6 participants) with an age range of 34 to 71 years and a male-female ratio of 3:1. The condyle and subcondylar surface were visible in 10 of 10 joints (100%), the disc in 7 of 10 joints (70%), and the pterygoid muscles in 6 of 10 joints (60%). In the 5 joints with magnetic resonance correlation, disc position and configuration were confirmed in all cases. CONCLUSIONS: We show the first sagittal transoral sonograms of the TMJ disc and associated joint components.

Acute Kidney Injury After Intravenous Versus Intra-Arterial Contrast Material Administration in a Paired Cohort.

OBJECTIVES: The aim of this study was to determine whether intra-arterial administration of contrast material is associated with a higher risk of acute kidney injury (AKI) compared with that of intravenous (IV) administration in a cohort of patients that received both routes of administration. MATERIALS AND METHODS: All patients who received both a contrast-enhanced computed tomography (CT) and a diagnostic or interventional cardiac catheterization between 2000 and 2014 were identified. Patients who lacked sufficient preprocedure and postprocedure serum creatinine results, who were on preexisting renal dialysis, or who underwent additional contrast-enhanced procedures within 7 days of either procedure were excluded. The rate of AKI (serum creatinine ≥0.3 mg/dL or 50% above baseline) was compared after CT scan and cardiac catheterization using McNemar test. RESULTS: A total of 1969 patients met all study inclusion criteria. The rate of AKI after CT scan was similar to the rate after catheterization when examining all patients (9.9% CT vs 11% catheterization, P = 0.12). A similar rate of AKI after both procedures was observed regardless of procedure order, catheterization type, and patient baseline estimated glomerular filtration rate. CONCLUSIONS: Intra-arterial administration of contrast material during cardiac catheterization had a similar risk of AKI as compared with that of CT scanning involving IV administration in a cohort of patients who underwent both procedures. These findings suggest that previously reported much higher rates of AKI after cardiac catheterization compared with that of IV contrast administration reflect higher baseline clinical risk factors for AKI in the former cohort compared with that in the latter.

Clinical Significance of Persistent Global and Focal Computed Tomography Nephrograms After Cardiac Catheterization and Their Relationships to Urinary Biomarkers of Kidney Damage and Procedural Factors: Pilot Study.

OBJECTIVES: We evaluate the relationships between persistent computed tomography (CT) nephrograms and acute kidney injury after cardiac catheterization (CC). We compare changes in urinary biomarkers kidney injury molecule 1 (KIM-1), cystatin C, and serum creatinine to procedural factors. MATERIALS AND METHODS: From 159 eligible patients without renal insufficiency (estimated glomerular filtration rate >60 mL/min), 40 random patients (age range, 42-81 years; mean age, 64 years; 25 men, 15 women) gave written informed consent to undergo unenhanced CT limited to their kidneys 24 hours after CC. Semiquantitative assessment for global nephrograms and quantitative assessment of focal nephrograms in each kidney was performed. Computed tomography attenuation (Hounsfield units) of the renal cortex was measured. Serum creatinine, KIM-1, and cystatin C were measured before and 24 hours after CC. RESULTS: Robust linear regression showed that both relative changes in KIM-1 and cystatin C had positive relationships with kidney CT attenuation (P = 0.012 and 0.002, respectively). Spearman rank correlation coefficient showed that both absolute changes and relative changes in KIM-1 and cystatin C had positive correlations with global nephrogram grades (P = 0.025 and 0.040, respectively, for KIM-1; P = 0.013 and 0.019, respectively, for cystatin C). CONCLUSIONS: Global nephrograms on unenhanced CT in patients who have undergone CC are significantly correlated with changes in urinary biomarkers for kidney damage.

Is the Presence of a Solitary Kidney an Independent Risk Factor for Acute Kidney Injury after Contrast-enhanced CT?

PURPOSE: To determine whether patients with a solitary kidney are at higher risk for contrast material-induced acute kidney injury (AKI) than matched control patients with bilateral kidneys. MATERIALS AND METHODS: This retrospective study was HIPAA compliant and approved by the institutional review board. Adult patients with bilateral kidneys or a solitary kidney from unilateral nephrectomy who underwent contrast material-enhanced computed tomography (CT) at this institution from January 2004 to August 2013 were identified. The effects of contrast material exposure on the rate of AKI--defined as an increase in maximal observed serum creatinine (SCr) level of either (a) ≥0.5 mg/dL (44.2 µmol/L) or (b) ≥0.3 mg/dL (26.52 µmol/L) or 50% over baseline within 24-72 hours of exposure--and 30-day post-CT emergent dialysis and death were determined after propensity score-based 1:3 matching of patients with solitary kidneys and control patients with bilateral kidneys. Differences in clinical characteristics and outcomes between the solitary and bilateral kidney groups were assessed by using the Wilcoxon rank sum test or Pearson χ(2) test prior to matching and by using conditional logistic regression after matching. RESULTS: Propensity score matching yielded a cohort of 247 patients with solitary kidneys and 691 patients with bilateral kidneys. The rate of AKI was similar between the solitary and bilateral kidney groups (SCr ≥ 0.5 mg/dL AKI definition odds ratio = 1.11 [95% confidence interval {CI}: 0.65, 1.86], P = .70; SCr ≥ 0.3 mg/dL or 50% over baseline AKI definition odds ratio = 0.96 [95% CI: 0.41, 2.07], P = .99). The rate of emergent dialysis was rare and also similar between cohorts (odds ratio = 1.87 [95% CI: 0.16, 16.4], P = .61). Although the rate of mortality was higher in the solitary kidney group (odds ratio = 1.70 [95% CI: 1.06, 2.71], P = .0202), chart review showed that no death was attributable to AKI. CONCLUSION: Our study did not demonstrate any significant differences in the rate of AKI, dialysis, or death attributable to contrast-enhanced CT in patients with a solitary kidney versus bilateral kidneys.

Risk of Acute Kidney Injury, Dialysis, and Mortality in Patients With Chronic Kidney Disease After Intravenous Contrast Material Exposure.

OBJECTIVE: To examine the effect of intravenous iodinated contrast material administration on the subsequent development of acute kidney injury (AKI), emergent dialysis, and short-term mortality using a propensity score-adjusted analysis of computed tomographic scan recipients with chronic kidney disease (CKD). PATIENTS AND METHODS: In this institutional review board-approved retrospective study, all patients with CKD who received a contrast-enhanced (contrast group) or unenhanced (noncontrast group) computed tomographic scan from January 1, 2000, to August 1, 2013 were identified. Patients were subdivided into CKD stage III (baseline estimated glomerular filtration rate, 30-59 mL/min per 1.73 m(2)) and CKD stage IV-V (baseline estimated glomerular filtration rate, <30 mL/min per 1.73 m(2)) subgroups and separately underwent propensity score generation, stratification, and 1:1 matching. Rates of AKI, 30-day emergent dialysis, and mortality were compared between contrast and noncontrast groups. Sensitivity analyses examining only patients with stable prescan serum creatinine levels and incorporating intravenous fluid administration at the time of the CT scan into the model were also performed. RESULTS: A total of 6902 patients (4496 CKD stage III, matched: 1220 contrast and 1220 noncontrast; 2086 CKD stage IV-V, matched: 491 contrast and 491 noncontrast) were included in the study. After propensity score adjustment, rates of AKI, emergent dialysis, and mortality were not significantly higher in the contrast group than in the noncontrast group in either CKD subgroup (CKD stage III: OR, 0.65-1.00; P<.001-.99 and CKD stage IV-V: OR, 0.93-2.33; P=.22-.99). Both sensitivity analyses revealed similar results. CONCLUSION: Intravenous contrast material administration was not associated with an increased risk of AKI, emergent dialysis, and short-term mortality in a cohort of patients with diminished renal function.

Delayed adverse reactions to the parenteral administration of iodinated contrast media.

OBJECTIVE: This article presents an overview of delayed adverse reactions (DARs) to parenteral iodinated contrast media and discusses the clinical nature, risk factors, mechanisms, and potential economic implications of these DARs. CONCLUSION: DARs to contrast media are not rare but are often not recognized as being linked to contrast administration and may be falsely ascribed to other drugs. These side effects are problematic because the patient is usually without medical supervision.

Intravenous contrast material exposure is not an independent risk factor for dialysis or mortality.

PURPOSE: To determine the risk of emergent dialysis and short-term mortality following intravenous iodinated contrast material exposure. MATERIALS AND METHODS: This single-center retrospective study was HIPAA compliant and institutional review board approved. All contrast material-enhanced (contrast group) and unenhanced (noncontrast group) abdominal, pelvic, and thoracic computed tomography scans from 2000-2010 were identified. Patients in the contrast and noncontrast groups were compared following propensity score-based 1:1 matching to reduce intergroup selection bias. Patients with preexisting diabetes mellitus, congestive heart failure, or chronic or acute renal failure were identified as high-risk patient subgroups for nephrotoxicity. The effects of contrast material exposure on the rate of acute kidney injury ( AKI acute kidney injury ) (serum creatinine level ≥ 0.5 mg/dL [44.2 µmol/L] above baseline within 24-72 hours of exposure) and dialysis or death within 30 days of exposure were determined by using odds ratios ( OR odds ratio s) and covariate-adjusted Cox proportional hazards models. Results were validated with a bootstrapped sensitivity analysis. RESULTS: The 1:1 matching on the basis of the propensity score yielded a cohort of 21 346 patients (10 673 in the contrast group, 10 673 in the noncontrast group). Within this cohort, the risks of AKI acute kidney injury ( OR odds ratio , 0.94; 95% confidence interval [ CI confidence interval ]: 0.83, 1.07; P = .38), emergent dialysis ( OR odds ratio , 0.96; 95% CI confidence interval : 0.54, 1.60; P = .89), and 30-day mortality (hazard ratio [ HR hazard ratio ], 0.97; 95% CI confidence interval : 0.87, 1.06; P = .45) were not significantly different between the contrast group and the noncontrast group. Although patients who developed AKI acute kidney injury had higher rates of dialysis and mortality, contrast material exposure was not an independent risk factor for either outcome for dialysis ( OR odds ratio , 0.89; 95% CI confidence interval : 0.40, 2.01; P = .78) or for mortality ( HR hazard ratio , 1.03; 95% CI confidence interval : 0.82, 1.32; P = .63), even among patients with compromised renal function or predisposing comorbidities. CONCLUSION: Intravenous contrast material administration was not associated with excess risk of AKI acute kidney injury , dialysis, or death, even among patients with comorbidities reported to predispose them to nephrotoxicity.

Is contrast medium osmolality a causal factor for contrast-induced nephropathy?

The exact pathophysiology of contrast-induced nephropathy (CIN) is not fully clarified, yet the osmotic characteristics of contrast media (CM) have been a significant focus in many investigations of CIN. Osmotic effects of CM specific to the kidney include transient decreases in blood flow, filtration fraction, and glomerular filtration rate. Potentially significant secondary effects include an osmotically induced diuresis with a concomitant dehydrating effect. Clinical experiences that have compared the occurrence of CIN between the various classes of CM based on osmolality have suggested a much less than anticipated advantage, if any, with a lower osmolality. Recent animal experiments actually suggest that induction of a mild osmotic diuresis in association with iso-osmolar agents tends to offset potentially deleterious renal effects of high viscosity-mediated intratubular CM stagnation.

Risk of intravenous contrast material-mediated acute kidney injury: a propensity score-matched study stratified by baseline-estimated glomerular filtration rate.

PURPOSE: To determine the effect of baseline estimated glomerular filtration rate (eGFR) on the causal association between intravenous iodinated contrast material exposure and subsequent development of acute kidney injury (AKI) in propensity score-matched groups of patients who underwent contrast material-enhanced or unenhanced computed tomography (CT). MATERIALS AND METHODS: This retrospective study was HIPAA compliant and institutional review board approved. All patients who underwent contrast-enhanced (contrast material group) or unenhanced (non-contrast material group) CT between 2000 and 2010 were identified and stratified according to baseline eGFR by using Kidney Disease Outcomes Quality Initiative cutoffs for chronic kidney disease into subgroups with eGFR of 90 or greater, 60-89, 30-59, and less than 30 mL/min/1.73 m(2). Propensity score generation and 1:1 matching of patients were performed in each eGFR subgroup. Incidence of AKI (serum creatinine [SCr] increase of ≥0.5 mg/dL [≥44.2 µmol/L] above baseline) was compared in the matched subgroups by using the Fisher exact test. RESULTS: A total of 12 508 propensity score-matched patients with contrast-enhanced and unenhanced scans met all inclusion criteria. In this predominantly inpatient cohort, the incidence of AKI significantly increased with decreasing baseline eGFR (P < .0001). However, this incidence was not significantly different between contrast material and non-contrast material groups in any eGFR subgroup; for the subgroup with eGFR of 90 or greater (n = 1642), odds ratio (OR) was 0.91 (95% confidence interval [CI]: 0.38, 2.15), P = .82; for the subgroup with eGFR of 60-89 (n = 3870), OR was 1.03 (95% CI: 0.66, 1.60), P = .99; for the subgroup with eGFR of 30-59 (n = 5510), OR was 0.94 (95% CI: 0.76, 1.18), P = .65; and for the subgroup with eGFR of less than 30 mL/min/1.73 m(2) (n = 1486), OR was 0.97 (95% CI: 0.72, 1.30), P = .89. CONCLUSION: Diminished eGFR is associated with an increased risk of SCr-defined AKI following CT examinations. However, the risk of AKI is independent of contrast material exposure, even in patients with eGFR of less than 30 mL/min/1.73 m(2).

Frequency of acute kidney injury following intravenous contrast medium administration: a systematic review and meta-analysis.

PURPOSE: To perform a systematic review and meta-analysis of controlled studies examining the incidence of acute kidney injury (AKI) and other outcomes in patients exposed to intravenous (i.v.) contrast medium compared with patients who underwent an imaging examination without contrast medium or were otherwise unexposed (control group). MATERIALS AND METHODS: MEDLINE, EMBASE, Scopus, and the Cochrane Library were searched for all articles published through September 2011 that contained search terms related to nephrotoxicity following intravenous contrast medium administration. Two independent reviewers identified studies in which the incidence of AKI in patients exposed to i.v. contrast medium was directly compared with the incidence of AKI in unexposed patients through analysis of changes in serum creatinine level or estimated glomerular filtration rate 48-72 hours following imaging procedures or admission. Study characteristics and outcomes of AKI, dialysis, and mortality were extracted by using a standardized protocol. Relative risk (RR) was calculated by using random-effects models and was tested in subgroups of different patient comorbidities, contrast medium types, and AKI diagnostic criteria. RR results of less than 1.00 indicated that there was a higher incidence of these outcomes in the group that did not receive contrast medium (non-contrast medium group). RESULTS: Of the 1489 studies originally identified, 13 nonrandomized studies (0.9%) representing 25,950 patients met inclusion criteria. In the group that received contrast medium (contrast medium group), risk of AKI (RR = 0.79; 95% confidence interval [CI]: 0.62, 1.02; P = .07), death (RR = 0.95; 95% CI: 0.55, 1.67; P = .87), and dialysis (RR = 0.88; 95% CI: 0.23, 3.43; P = .85) was similar, compared with the risk of AKI in the non-contrast medium group. This pattern was observed regardless of i.v. contrast medium type, diagnostic criteria for AKI, or whether patients had diabetes mellitus or renal insufficiency. CONCLUSION: Controlled contrast medium-induced nephropathy studies demonstrate a similar incidence of AKI, dialysis, and death between the contrast medium group and control group. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12121460/-/DC1.

Persistent CT nephrograms following cardiac catheterisation and intervention: initial observations.

OBJECTIVES: To describe persistent nephrographic patterns detected by unenhanced renal CT at 24 h after cardiac catheterisation and intervention. METHODS: This prospective study was Health Insurance Portability and Accountability Act-compliant and institutional review board approved. Twenty-nine patients (20 men, nine women; average age 63.27 and range 41-85 years) agreed to undergo unenhanced dual-energy computed tomography (CT) limited to their kidneys at 24 h after cardiac catheterisation. CT attenuation values (Hounsfield units) were made from the cortical and medullary regions and single kidney total parenchymal iodine values (milligrams) were measured. Spearman's rank correlation coefficient and a two-sided Fisher's exact test were used in the statistics. RESULTS: Focal nephrograms were observed in at least one kidney (range, one to five regions per kidney) in 10/29 (34%) of patients and bilateral global nephrograms in 13/29 (45%) of patients. Focal nephrograms correlated with cardiac catheterisation fluoroscopic time (r = 0.48; P = 0.0087). For global nephrograms, the total iodine content of right and left kidneys correlated with fluoroscopic time (r = 0.79 and 0.76; P < 0.0001, respectively) and the amount of contrast material (CM) used (r = 0.77 and r = 0.74; P < 0.0001, respectively). CONCLUSION: Persistent focal and global nephrograms occur commonly as assessed by non-contrast CT at 24 h post cardiac catheterisation and our observations suggest they could be related to procedural factors.

Delayed adverse reaction to contrast-enhanced CT: a prospective single-center study comparison to control group without enhancement.

PURPOSE: To prospectively assess the incidence of delayed adverse reactions (DARs) in patients undergoing contrast material-enhanced computed tomography (CT) with the low osmolar nonionic contrast agent iohexol and compare with the incidence of DARs in patients undergoing unenhanced CT as control subjects. MATERIALS AND METHODS: Institutional review board approval and informed written consent for this prospective study were obtained. The study was HIPAA compliant. Patients undergoing CT for routine indications were enrolled from a random next-available scheduling template by an on-site clinical trials monitor. All subjects received a questionnaire asking them to indicate any DAR occurring later than 1 hour after their examination. Sixteen manifestations were listed and included rash, skin redness, skin swelling, nausea, vomiting, and dizziness, among others. To ensure maximal surveillance, a clinical trials coordinator initiated direct telephone contact for further assessment. Patients suspected of having moderately severe cutaneous reactions were invited to return for a complete dermatologic clinical assessment including skin biopsy, if indicated. Statistical analysis was performed by using a two-sided Wilcoxon-Mann-Whitney test, a logistic regression utilizing a chi(2) test to adjust for sex and age, and a two-sided Fisher exact test. RESULTS: A total of 539 patients (258 receiving iohexol and 281 not receiving contrast material) were enrolled. DARs were observed in 37 (14.3%) of 258 subjects receiving iohexol and in seven (2.5%) of 281 subjects in the control group (P < .0001, chi(2) test) after adjusting for sex and age. Specific manifestations of DARs that were significantly more frequent at contrast-enhanced CT were skin rash (P = .0311), skin redness (P = .0055), skin swelling (P = .0117), and headache (P = .0246). DARs involving the skin included generalized rashes of the face, neck, chest, back, and extremities and were often associated with swelling, erythema, and pruritus. CONCLUSION: This study substantiates a frequent occurrence of DARs at contrast-enhanced CT compared with that in control subjects. Continued growth in the use of contrast-enhanced CT suggests a need for greater awareness and attention to prevention and management.

Clinical factors associated with dense and wedge-shaped nephrograms detected 24 h after chemoembolization.

This investigation aimed to evaluate patient characteristics and procedural factors associated with abnormal nephrograms encountered on noncontrast computed axial tomography (CAT) obtained 24-h after transarterial chemoembolization (TACE) for primary and metastatic hepatic malignancies. Sixty hepatic chemoembolization procedures were performed in 29 patients who had a median age of 63 years (range 42-79). The male-to-female ratio was 16:13. Noncontrast CAT scans were obtained approximately 24 h after TACE as part of our institutional protocol and were examined for persistent renal nephrograms. These findings were compared with clinical and procedural parameters to determine whether there was any association with these factors or with the occurrence of acute renal failure (ARF). Abnormally persistent CAT nephrograms were observed 24 h after 28 of 60 (46.7%) TACE procedures, of which 14 (23.3%) were persistent, bilaterally dense, global nephrograms, and 14 (23.3%) were small, wedge-shaped, and focal nephrograms. The change in serum creatinine from baseline to 24 h was significantly greater (p=0.031) in the global nephrogram group. The presence of cirrhosis, Child-Pugh score, procedure time, baseline renal insufficiency, and lower periprocedural mean arterial blood pressure were also statistically significantly associated with the occurrence of bilateral globally dense nephrograms. The procedure time was statistically significantly associated with the occurrence of wedge-like focally persistent nephrograms. Global, persistently dense nephrograms and wedge-shaped focally persistent nephrograms are not infrequently observed after TACE. Persistent global nephrograms can be an important clinical indicator of ARF. The wedge nephrogram may represent focal renal ischemia.