Cataract surgery and intraocular lens placement in patients with Fuchs corneal dystrophy: a review of the current literature.

PURPOSE OF REVIEW: Late-onset Fuchs endothelial corneal dystrophy (FECD) is seen in approximately 4% of individuals over the age of 40. With the growing population of adults over the age of 65, ophthalmologists need to be aware of the preoperative, perioperative, and postoperative considerations involved in cataract surgery in Fuchs patients. RECENT FINDINGS: Management of cataract patients with FECD requires preoperative assessment of endothelial cell size, density, and morphology. Considerations for perioperative endothelial cell loss include patients with hyperopia and shallow anterior chambers, phacoemulsification technique, transfer of ultrasonic energy to the cornea, corneal-protective perioperative agents, as well as thermal and mechanical damage. SUMMARY: Ophthalmologists performing cataract surgery on patients with FECD must carefully consider the risks of endothelial cell loss during surgery and minimize the risk of corneal decompensation after surgery. Preoperative management should evaluate the severity of the FECD as well as individual factors such as cataract density, the health and thickness of the cornea, and the anterior chamber depth. Perioperative techniques, adjustments to biometry calculations, and intraocular lens (IOL) selection may help optimize visual outcomes and recovery time.

Bosniak Classification of Cystic Renal Masses, Version 2019: An Update Proposal and Needs Assessment.

Cystic renal cell carcinoma (RCC) is almost certainly overdiagnosed and overtreated. Efforts to diagnose and treat RCC at a curable stage result in many benign neoplasms and indolent cancers being resected without clear benefit. This is especially true for cystic masses, which compared with solid masses are more likely to be benign and, when malignant, less aggressive. For more than 30 years, the Bosniak classification has been used to stratify the risk of malignancy in cystic renal masses. Although it is widely used and still effective, the classification does not formally incorporate masses identified at MRI or US or masses that are incompletely characterized but are highly likely to be benign, and it is affected by interreader variability and variable reported malignancy rates. The Bosniak classification system cannot fully differentiate aggressive from indolent cancers and results in many benign masses being resected. This proposed update to the Bosniak classification addresses some of these shortcomings. The primary modifications incorporate MRI, establish definitions for previously vague imaging terms, and enable a greater proportion of masses to enter lower-risk classes. Although the update will require validation, it aims to expand the number of cystic masses to which the Bosniak classification can be applied while improving its precision and accuracy for the likelihood of cancer in each class.

Influence of Clinical Factors on Risk of Contrast-Induced Nephrotoxicity From IV Iodinated Low-Osmolality Contrast Material in Patients With a Low Estimated Glomerular Filtration Rate.

OBJECTIVE. The objective of our study was to explore whether clinical factors historically associated with contrast material-causative kidney injury (contrast-induced nephrotoxicity [CIN]) increase risk after use of IV iodinated low-osmolality contrast material (LOCM) in patients with stage IIIb-V chronic kidney disease. MATERIALS AND METHODS. In this retrospective hypothesis-generating study, 1:1 propensity score matching was used to assess post-CT acute kidney injury (AKI) after unenhanced or contrast-enhanced CT in patients with stable estimated glomerular filtration rate (eGFR; 1112 patients with an eGFR = 30-44 mL/min/1.73 m2 and 86 patients with an eGFR < 30 mL/min/1.73 m2 and no dialysis). Historical risk factors including diabetes mellitus, age more than 60 years, hypertension, loop diuretic use, hydrochlorothiazide use, and cardiovascular disease were evaluated for modulation of CIN risk. Stepwise multivariable logistic regression was performed. RESULTS. Overall IV LOCM was an independent risk factor for post-CT AKI in patients with an eGFR of less than 30 mL/min/1.73 m2 (odds ratio, 3.96 [95% CI, 1.29-12.21]; p = 0.016) but not in those with an eGFR of 30-44 mL/min/1.73 m2 (p = 0.24). In patients with an eGFR of less than 30 mL/min/1.73 m2, the tested covariates did not significantly modify the risk of CIN (p = 0.096-0.832). In patients with an eGFR of 30-44 mL/min/1.73 m2, risk of CIN emerged in those with cardiovascular disease (p = 0.015; number needed to harm from LOCM = 11 patients); the other tested cofactors had no significant effect (p = 0.108-0.822). CONCLUSION. CIN was observed when eGFR was less than 30 mL/min/1.73 m2. In those with an eGFR of 30-44 mL/min/1.73 m2, CIN was not observed with LOCM alone but was observed in the presence of cardiovascular disease. Other cofactors historically thought to increase CIN risk (e.g., diabetes mellitus) did not increase risk of CIN. Further study is needed to determine whether these exploratory results are true associations.

Gadolinium Retention: A Research Roadmap from the 2018 NIH/ACR/RSNA Workshop on Gadolinium Chelates.

Gadolinium-based contrast agents (GBCAs) have revolutionized MRI, enabling physicians to obtain crucial life-saving medical information that often cannot be obtained with other imaging modalities. Since initial approval in 1988, over 450 million intravenous GBCA doses have been administered worldwide, with an extremely favorable pharmacologic safety profile; however, recent information has raised new concerns over the safety of GBCAs. Mounting evidence has shown there is long-term retention of gadolinium in human tissues. Further, a small subset of patients have attributed a constellation of symptoms to GBCA exposure, although the association of these symptoms with GBCA administration or gadolinium retention has not been proven by scientific investigation. Despite evidence that macrocyclic GBCAs show less gadolinium retention than linear GBCAs, the safety implications of gadolinium retention are unknown. The mechanism and chemical forms of gadolinium retention, as well as the biologic activity and clinical importance of these retained gadolinium species, remain poorly understood and underscore the need for additional research. In February 2018, an international meeting was held in Bethesda, Md, at the National Institutes of Health to discuss the current literature and knowledge gaps about gadolinium retention, to prioritize future research initiatives to better understand this phenomenon, and to foster collaborative standardized studies. The greatest priorities are to determine (a) if gadolinium retention adversely affects the function of human tissues, (b) if retention is causally associated with short- or long-term clinical manifestations of disease, and (c) if vulnerable populations, such as children, are at greater risk for experiencing clinical disease. The purpose of the research roadmap is to highlight important information that is not known and to identify and prioritize needed research. ©RSNA, 2018 Online supplemental material is available for this article .

Novel Quality Indicators for Radiologists Interpreting Abdominopelvic CT Images: Risk-Adjusted Outcomes Among Emergency Department Patients With Right Lower Quadrant Pain.

OBJECTIVE: The purpose of this study was to determine whether individual radiologists are predictive of important relevant health outcomes among emergency department (ED) patients undergoing abdominopelvic CT for right lower quadrant pain. MATERIALS AND METHODS: This single-institution retrospective cohort study included 2169 patients undergoing abdominopelvic CT for right lower quadrant pain in the ED from February 1, 2012, through August 31, 2016. CT examinations were interpreted by 15 radiologists (four emergency, 11 abdominal) who each reported on more than 70 CT examinations in the cohort. After risk adjustment for covariates thought to influence outcome, including baseline risk (demographics, 30 Elixhauser comorbidities, number of previous ED visits), clinical factors (vital signs, triage and pain scores, laboratory data), and system factors (time of CT, resident involvement, attending physician experience), multivariable models were built to analyze the effect of individual radiologists on four important health outcomes: hospital admission (primary outcome), readmission within 30 days, abdominal surgery, and image-guided percutaneous aspiration or drainage. RESULTS: Radiologists had a mean experience of 14 years (range, 2-36 years) and read a mean of 145 CT examinations in the study cohort (range, 73-253 examinations). Unadjusted event rates across the 15 radiologists were 38-55% (admission), 11-21% (readmission), 10-26% (surgery), and 0-3% (aspiration or drainage). After risk adjustment, individual radiologists were not a significant multivariable predictor of hospital admission, readmission within 30 days, abdominal surgery, or image-guided abdominal percutaneous aspiration or drainage (all p > 0.05). CONCLUSION: Individual radiologists were indistinguishable both within group and between group by emergency and abdominal specialization for the prediction of major patient outcomes after abdominopelvic CT performed for right lower quadrant pain in the ED.

Intravenous Corticosteroid Premedication Administered 5 Hours before CT Compared with a Traditional 13-Hour Oral Regimen.

Purpose To determine if the allergic-like breakthrough reaction rate of intravenous corticosteroid prophylaxis administered 5 hours before contrast material-enhanced computed tomography (CT) is noninferior to that of a traditional 13-hour oral regimen. Materials and Methods Institutional review board approval was obtained and informed consent waived for this retrospective noninferiority cohort study. Subjects (n = 202) who completed an accelerated 5-hour intravenous corticosteroid premedication regimen before low-osmolality contrast-enhanced CT for a prior allergic-like or unknown-type reaction to iodine-based contrast material from June 1, 2008, to June 30, 2016, were identified. The breakthrough reaction rate was compared by using the Farrington and Manning noninferiority likelihood score to test subjects premedicated with a traditional 13-hour oral regimen (2.1% [13 of 626]). All subjects were premedicated for a prior allergic-like or unknown-type reaction to iodine-based contrast material. A noninferiority margin of 4.0% was selected to allow for no more than a clinically negligible 6.0% breakthrough reaction rate in the cohort that received 5-hour intravenous corticosteroid prophylaxis. Results The breakthrough reaction rate for 5-hour intravenous prophylaxis was 2.5% (five of 202 patients; 95% confidence interval: 0.8%, 5.7%), which was noninferior to the 2.1% (13 of 626 patients; 95% confidence interval: 1.1%, 3.5%) rate for the 13-hour regimen (P = .0181). The upper limits of the confidence interval for the difference between the two rates was 3.7% (0.4%; 95% confidence interval: -1.6%, 3.7%), which was within the 4.0% noninferiority margin. All breakthrough reactions were of equal or lesser severity to those of the index reactions (two severe, one moderate, and one mild reaction). Conclusion Accelerated intravenous premedication with corticosteroids beginning 5 hours before contrast-enhanced CT has a breakthrough reaction rate noninferior to that of a 13-hour oral premedication regimen. © RSNA, 2017.

Recurrence of Colonic Diverticulitis: Identifying Predictive CT Findings-Retrospective Cohort Study.

Purpose To identify computed tomographic (CT) findings that are predictive of recurrence of colonic diverticulitis. Materials and Methods Institutional review board approval was obtained for this HIPAA-compliant, retrospective cohort study. Six abdominal fellowship-trained radiologists reviewed the CT studies of 440 consecutive subjects diagnosed with acute colonic diverticulitis between January 2004 and May 2008 to determine the involved segments, maximum wall thickness in the inflamed segment, severity of diverticulosis, presence of complications (abscess, fistula, stricture, or perforation), and severity of the inflammation. Electronic medical records were reviewed for a 5-year period after the patients' first CT study to determine clinical outcomes. Predictors of diverticulitis recurrence were assessed with univariate and multiple Cox proportional hazard regression models. Results Colonic diverticulitis most commonly involved the rectosigmoid (70%, 309 of 440) and descending (30%, 133 of 440) colon segments. Complicated diverticulitis was present in 22% (98 of 440) of patients. On the basis of the results of univariate analysis, significant predictors of diverticulitis recurrence were determined to be maximum colonic wall thickness in the inflamed segment (hazard ratio [HR], 1.07 per every millimeter of increase in wall thickness; P < .001), presence of a complication (HR, 1.75; P = .002), and subjective severity of inflammation (HR, 1.36 for every increase in severity category; P value for linear trend = .003). The difference in maximum wall thickness in the inflamed segment (HR, 1.05 per millimeter; P = .016) and subjective inflammation severity (HR, 1.29 per category; P = .018)remained statistically significant in a Cox multiple regression model. Conclusion Maximum colonic wall thickness and subjective severity of acute diverticulitis allow prediction of recurrent diverticulitis and may be useful for stratifying patients according to the need for elective partial colectomy. © RSNA, 2017 Online supplemental material is available for this article.

Indirect Cost and Harm Attributable to Oral 13-Hour Inpatient Corticosteroid Prophylaxis before Contrast-enhanced CT.

PURPOSE: To estimate the effect of an oral 13-hour inpatient corticosteroid premedication regimen on length of stay, hospital cost, and hospital-acquired infections (HAIs) by using a combination of real and hypothetical study populations. MATERIALS AND METHODS: Institutional review board approval was obtained and informed consent waived for this HIPAA-compliant retrospective study. Inpatients who received an oral 13-hour corticosteroid premedication regimen before contrast material-enhanced CT (n = 1424) from 2008 to 2013 were matched by age, sex, and year when CT was performed to a control cohort (n = 1425) of patients who underwent contrast-enhanced CT without premedication and who had similar rates of 13 comorbid diseases. Length of stay in the hospital and time from admission to CT were compared by using the Mann-Whitney U test. Rates of prospectively reported HAIs were compared by using χ(2) tests. The indirect cost and risk of HAI with premedication were estimated by using published data. RESULTS: Premedicated inpatients had a significantly longer median length of stay (+25 hours; 158 vs 133 hours, P < .001), a significantly longer median time to CT (+25 hours, 42 vs 17 hours, respectively; P < .001), and a significantly greater risk of HAI (5.1% [72 of 1424] vs 3.1% [44 of 1424], respectively; P = .008) compared with nonpremedicated control subjects. On the basis of these data and existing references, the prolonged length of stay was estimated to result in 0.04 HAI-related deaths and a cost of $159 131 (in U.S. dollars) for each prevented reaction of any severity and 32 HAI-related deaths and a cost of $131 211 400 for each prevented reaction-related death. CONCLUSION: Oral 13-hour inpatient corticosteroid prophylaxis is associated with substantial cost relative to its modest benefit, and may cause more indirect harm than the direct harm that it prevents.

Age, Gender and R.E.N.A.L. Nephrometry Score do not Improve the Accuracy of a Risk Stratification Algorithm Based on Biopsy and Mass Size for Assigning Surveillance versus Treatment of Renal Tumors.

PURPOSE: A previously published risk stratification algorithm based on renal mass biopsy and radiographic mass size was useful to designate surveillance vs the need for immediate treatment of small renal masses. Nonetheless, there were some incorrect assignments, most notably when renal mass biopsy indicated low risk malignancy but final pathology revealed high risk malignancy. We studied other factors that might improve the accuracy of this algorithm. MATERIALS AND METHODS: For 202 clinically localized small renal masses in a total of 200 patients with available R.E.N.A.L. (radius, exophytic/endophytic, nearness of tumor to collecting system or sinus, anterior/posterior, hilar tumor touching main renal artery or vein and location relative to polar lines) nephrometry score, preoperative renal mass biopsy and final pathology we assessed the accuracy of management assignment (surveillance vs treatment) based on the previously published risk stratification algorithm as confirmed by final pathology. Logistic regression was used to determine whether other factors (age, gender, R.E.N.A.L. score, R.E.N.A.L. score components and nomograms based on R.E.N.A.L. score) could improve assignment. RESULTS: Of the 202 small renal masses 53 (26%) were assigned to surveillance and 149 (74%) were assigned to treatment by the risk stratification algorithm. Of the 53 lesions assigned to surveillance 25 (47%) had benign/favorable renal mass biopsy histology while in 28 (53%) intermediate renal mass biopsy histology showed a mass size less than 2 cm. Nine of these 53 masses (17%) were incorrectly assigned to surveillance in that final pathology indicated the need for treatment (ie intermediate histology and a mass greater than 2 cm or unfavorable histology). Final pathology confirmed a correct assignment in all 149 masses assigned to treatment. None of the additional parameters assessed improved assignment with statistical significance. CONCLUSIONS: Age, gender, R.E.N.A.L. nephrometry score, R.E.N.A.L. score components and nomograms or combinations of these factors do not improve the predictive performance of a small renal mass management risk stratification algorithm based on renal mass biopsy and radiographic mass size.

Clinical Effectiveness of Prospectively Reported Sonographic Twinkling Artifact for the Diagnosis of Renal Calculus in Patients Without Known Urolithiasis.

OBJECTIVE: The purpose of this study was to determine the clinical effectiveness of prospectively reported sonographic twinkling artifact for the diagnosis of renal calculus in patients without known urolithiasis. MATERIALS AND METHODS: All ultrasound reports finalized in one health system from June 15, 2011, to June 14, 2014, that contained the words "twinkle" or "twinkling" in reference to suspected renal calculus were identified. Patients with known urolithiasis or lack of a suitable reference standard (unenhanced abdominal CT with ≤ 2.5-mm slice thickness performed ≤ 30 days after ultrasound) were excluded. The sensitivity, specificity, and positive likelihood ratio of sonographic twinkling artifact for the diagnosis of renal calculus were calculated by renal unit and stratified by two additional diagnostic features for calcification (echogenic focus, posterior acoustic shadowing). RESULTS: Eighty-five patients formed the study population. Isolated sonographic twinkling artifact had sensitivity of 0.78 (82/105), specificity of 0.40 (26/65), and a positive likelihood ratio of 1.30 for the diagnosis of renal calculus. Specificity and positive likelihood ratio improved and sensitivity declined when the following additional diagnostic features were present: sonographic twinkling artifact and echogenic focus (sensitivity, 0.61 [64/105]; specificity, 0.65 [42/65]; positive likelihood ratio, 1.72); sonographic twinkling artifact and posterior acoustic shadowing (sensitivity, 0.31 [33/105]; specificity, 0.95 [62/65]; positive likelihood ratio, 6.81); all three features (sensitivity, 0.31 [33/105]; specificity, 0.95 [62/65]; positive likelihood ratio, 6.81). CONCLUSION: Isolated sonographic twinkling artifact has a high false-positive rate (60%) for the diagnosis of renal calculus in patients without known urolithiasis.

Contrast media controversies in 2015: imaging patients with renal impairment or risk of contrast reaction.

OBJECTIVE: The incidence and significance of complications related to intravascular contrast material administration have become increasingly controversial. This review will highlight current thinking regarding the imaging of patients with renal impairment and those at risk for an allergiclike contrast reaction. CONCLUSION: The risk of contrast-induced acute kidney injury remains uncertain for patients with an estimated glomerular filtration rate (GFR) less than 45 mL/min/1.73 m(2), but if there is a risk, it is greatest in those with estimated GFR less than 30 mL/min/1.73 m(2). In this population, low-risk gadolinium-based contrast agents appear to have a large safety margin. Corticosteroid prophylaxis remains the standard of care in the United States for patients identified to be at high risk of a contrast reaction, but it has an incomplete mitigating effect on contrast reaction rates and the number needed to treat is large.

Rates of Breakthrough Reactions in Inpatients at High Risk Receiving Premedication Before Contrast-Enhanced CT.

OBJECTIVE: The purpose of this study was to determine the rate of allergiclike breakthrough reactions among inpatients at high risk receiving premedication before undergoing CT with IV iodinated low-osmolality contrast material (LOCM). MATERIALS AND METHODS: Inpatients (n = 1051) completing a 13-hour corticosteroid and diphenhydramine premedication regimen before LOCM-enhanced CT from January 1, 2010, through December 31, 2013, were included in the study. Breakthrough reaction rates were compared with the ordinary allergiclike reaction rate in the general population (0.6% [545/84,928]) by use of chi-square tests. Multivariate logistic regression was performed. Number needed to treat (NNT) was calculated for patients premedicated for a previous contrast reaction. RESULTS: Sixty percent (626/1051) of premedicated patients had had a previous reaction to iodinated contrast material, and 40% (425/1051) were premedicated for other reasons. The overall breakthrough reaction rates were 1.2% (13/1051) (p < 0.0001 vs the general population), 2.1% (13/626) for those with a previous iodinated contrast reaction (p < 0.0001), and 0% (0/425) for those premedicated for other reasons (p = 0.18). There were no severe breakthrough reactions. Younger age (p = 0.046; odds ratio, 1.03 per year; 95% CI, 1.001-1.07) and multiple indications for premedication (p < 0.0001; odds ratio, 2.7 per indication; 95% CI, 1.5-4.8) significantly increased the likelihood of a breakthrough reaction. The estimated NNTs were 69 (95% CI, 39-304) to prevent a reaction of any severity and 569 (95% CI, 389-1083) to prevent a severe reaction. CONCLUSION: Patients premedicated for a previous reaction to iodinated contrast material have a breakthrough reaction rate 3-4 times the ordinary reaction rate in the general population. Patients receiving premedication for other reasons have a breakthrough reaction rate near 0%. Many patients must receive premedication to prevent one reaction.

Effect of Model-Based Iterative Reconstruction on CT Number Measurements Within Small (10-29 mm) Low-Attenuation Renal Masses.

OBJECTIVE: The purpose of this study was to assess the effect of model-based iterative reconstruction (MBIR) on CT number measurements within small (10-29 mm) low-attenuation renal masses. MATERIALS AND METHODS: One hundred 10- to 29-mm exophytic or endophytic low-attenuation renal lesions imaged with CT (unenhanced and nephrographic [100 seconds] phases, 120 kVp, variable mA, 2.5-mm slice thickness) were identified in 100 patients. The raw CT source data were prospectively reconstructed twice: once using Veo MBIR and once using a blend of 30% adaptive statistical iterative reconstruction (ASiR) and filtered back projection (FBP). Lesions were chosen to form four equal-sized (n = 25) groups stratified by lesion size (10-19 or 20-29 mm) and growth pattern (endophytic or exophytic). Attenuation (in HU) was measured using identical ROIs and compared with two-tailed t tests. The effects of patient diameter and lesion anatomy on attenuation discrepancies of 5 HU or more were assessed using binary logistic regression. RESULTS: Mean MBIR attenuation was not significantly different than mean 30% ASiR/FBP attenuation in the overall study population (unenhanced phase, 17 ± 13 vs 17 ± 13 HU, p = 0.74; nephrographic phase, 31 ± 27 vs 30 ± 26 HU, p = 0.89) or in any subgroup (p = 0.63-0.95). Only lesion size predicted discrepancies of 5 HU or more (p = 0.008; odds ratio, 1.20 [95% CI, 1.05-1.34] per 1 mm decrease) (p = 0.19-0.98 for the other variables). Seven lesions had enhancement of 20 HU or more with only one reconstruction method (MBIR = 4; 30% ASiR = 3). CONCLUSION: Veo MBIR has no significant or consistent effect on attenuation measurements within small (10-29 mm) low-attenuation renal masses and is therefore unlikely to change clinically accepted attenuation thresholds for renal mass characterization.

Abdominopelvic hemorrhage: correlation of CT positivity with the subsequent decision to perform blood transfusion.

The purpose of this study is to determine the role of computed tomography (CT) on the decision to administer blood transfusions in patients with abdominopelvic hemorrhage (trauma, surgery, invasive procedure, and spontaneous) and to determine the clinical parameters most likely to influence the decision to administer blood transfusions in patients with spontaneous abdominopelvic hemorrhage. In this IRB approved and HIPPA compliant study, retrospective analysis was performed on 298 patients undergoing abdominal and pelvic CT for suspected abdominopelvic hemorrhage and the CT reports and electronic medical records were reviewed. Odds ratios and 95% CI were calculated to compare the odds of abdominopelvic hemorrhage and transfusion for categorical and continuous predictors. The presence of abdominopelvic hemorrhage by CT was significantly associated with blood transfusions for trauma patients (p-value <0.0001) only. 106 patients with suspected spontaneous abdominopelvic hemorrhage had the lowest CT positivity rate (n = 23, 21.7%) but the highest blood transfusion rate (n = 62, 58.5%) compared to the patients with abdominopelvic hemorrhage from known preceding causes. In patients with spontaneous abdominopelvic hemorrhage, low hemoglobin and hematocrit levels immediately prior to obtaining the CT study were more predictive for receiving a blood transfusion (p-value <0.0001) than the presence of hemorrhage by CT. CT positivity is strongly correlated with the decision to administer blood transfusions for patients with abdominopelvic hemorrhage from trauma, indicating that CT studies play a significant role in determining the clinical management of trauma patients. For patients with spontaneous abdominopelvic hemorrhage, the decision to transfuse depends not on the CT study but on the patient's hemoglobin and hematocrit levels. CT studies should therefore not be performed for the sole purpose of determining the need for blood transfusion in patients with spontaneous abdominopelvic hemorrhage.

The challenges in assessing contrast-induced nephropathy: where are we now?

OBJECTIVE: The objective of our study was to exposit the shifting perspectives on contrast-induced nephropathy (CIN) for IV low-osmolar iodinated contrast media. CONCLUSION: The historically inflated risk of CIN reflects logistic and intellectual pitfalls that continue to confound the study of this disease. Recent advances have clarified that the incidence of CIN is much lower than previously thought, but there are lingering questions. We suggest that CIN is likely real but is rare and offer directions for future study.

In vivo predictors of renal cyst pseudoenhancement at 120 kVp.

OBJECTIVE: The purpose of this article is to assess the effects of various CT, patient, and renal cyst characteristics on the occurrence of pseudoenhancement in in vivo renal mass CT examinations using subtraction MRI as the reference standard. MATERIALS AND METHODS: Adult patients imaged with 120-kVp standard kernel biphasic renal mass protocol CT and dynamic contrast-enhanced MRI of the abdomen from January 1, 2005, through May 4, 2012, were identified. Those with nonenhancing Bosniak categories I and II cysts on MRI were selected (n = 33 patients; 110 cysts). By treating measured cyst enhancement (nephrographic CT attenuation minus unenhanced CT attenuation) as either a continuous or categoric outcome variable, a variety of CT, patient-level, and renal cyst characteristics were assessed using mixed effect multivariate models. RESULTS: On univariate assessment, cysts that exhibited pseudoenhancement (> 10 HU) were significantly more endophytic (p = 0.02), significantly smaller (p = 0.0004), and adjacent to significantly higher attenuation renal parenchyma in the nephrographic phase (p = 0.02). On multivariate assessment, cyst diameter (p < 0.0001) and background nephrographic phase parenchymal attenuation (p = 0.003) were the strongest in vivo predictors of pseudoenhancement. The odds of pseudoenhancement occurring increased by 2.14 (95% CI, 1.41-3.23) for every 5-mm decrease in renal cyst diameter and increased by 2.45 (95% CI, 1.41-4.26) for every 25-HU increase in enhanced renal parenchymal attenuation. Endophytic growth was not significant in the multivariate analyses (p = 0.07). CONCLUSION: Renal cyst size and enhanced renal parenchymal attenuation are better in vivo predictors of pseudoenhancement than is endophytic growth pattern.

Assessment of 1 mSv urinary tract stone CT with model-based iterative reconstruction.

OBJECTIVE: The purpose of this study was to evaluate stone detection, assessment of secondary signs of stone disease, and diagnostic confidence utilizing submillisievert CT with model-based iterative reconstruction (MBIR) in a North American population with diverse body habitus. MATERIALS AND METHODS: Fifty-two adults underwent stone CT using a split-dose protocol; weight-based projected volume CT dose index (CTDIvol) and dose-length product (DLP) were divided into two separate acquisitions at 80% and 20% dose levels. Images were reconstructed with MBIR. Five blinded readers counted stones in three size categories and rated "overall diagnostic confidence" and "detectability of secondary signs of stone disease" on a 0-4 scale at both dose levels. Effective dose (ED) in mSv was calculated as DLP multiplied by conversion coefficient, k, equal to 0.017. RESULTS: Mean ED (80%, 3.90±1.44 mSv; vs 20%, 0.97±0.34 mSv [p<0.001]) and number of stones detected (80%, 193.6±25.0; vs 20%, 154.4±15.4 [p=0.03]) were higher in scans at 80% dose level. Intrareader correlation between scans at 80% and 20% dose levels was excellent (0.83-0.97). With 80% scans as reference standard, mean sensitivity and specificity at 20% varied with stone size (<3 mm, 74% and 77%; ≥3 mm, 92% and 82%). The 20% scans scored lower than 80% scans in diagnostic confidence (2.46±0.50; vs 3.21±0.36 [p<0.005]) and detectability of secondary signs (2.41±0.39; vs 3.19±0.29 [p<0.005]). CONCLUSION: Aggressively dose-reduced (~1 mSv) MBIR scans detected most urinary tract stones of 3 mm or larger but underperformed the low-dose reference standard (3-4 mSv) scans in small (<3 mm) stone detection and diagnostic confidence.

Renal remodeling after abdominal radiation therapy: parenchymal and functional changes.

OBJECTIVE: The purpose of this study was to quantify changes in renal length, volume, and function over time after upper abdominal radiation therapy. MATERIALS AND METHODS: Imaging and clinical data were retrospectively reviewed for 27 adults with abdominal radiation therapy between 2001 and 2012. All had two kidneys, radiation exposure to one kidney, and survival of at least 1 year after therapy. Mean prescribed dose was 52 ± 9 Gy to extrarenal targets. Length and volume of exposed and unexposed kidneys were measured on CT scans before treatment (baseline) and at intervals 0-3, 3-6, 6-12, 12-24, 24-36, and more than 36 months after completion of radiotherapy. Serum creatinine was correlated at each interval. Mixed-models ANOVA was used to test renal length and volume, serum creatinine, and time against multiple models to assess for temporal effects; specific time intervals were compared in pairwise manner. RESULTS: Mean follow-up duration was 35 months (range, 5-94 months). Exposed kidney length and volume progressively decreased from baseline throughout follow-up, with mean loss of 23% (p < 0.001) and 47% (p < 0.001), respectively. Slight increase in unexposed kidney length was not significant. Mean serum creatinine increased from 0.86 ± 0.18 mg/dL at baseline to 1.12 ± 0.27 mg/dL at 12-24 months (p < 0.001), then stabilized. CONCLUSION: Kidneys exposed to radiation during therapy of adjacent malignancies exhibited continuous progressive atrophy for the entire follow-up period, nearly 8 years. Volume changes were twice as great as length changes. Renal function also declined. To accurately interpret follow-up studies in cancer survivors, radiologists should be aware of the potential for progressive renal atrophy, even many years after radiation therapy.

Variability in computed tomography diameter measurements of solid renal masses.

PURPOSE: To determine whether the frequency of intra-observer measurement discrepancies ≥5 mm for solid renal masses varies by renal mass characteristics and CT contrast phase. MATERIALS AND METHODS: This HIPAA-compliant retrospective study was approved by our IRB. We selected single CT images performed during the nephrographic phase (NP) of renal enhancement in 97 patients, each with a single solid renal mass. Mass location, margin, heterogeneity, and growth pattern were assessed. Six readers measured each mass on two occasions >3 weeks apart. Readers also measured the masses on images in 50 patients who had corticomedullary phase (CMP) images obtained during the same study. Results were assessed using Chi-square/Fisher's exact and Wilcoxon Signed Rank tests, and logistic regression analyses. RESULTS: For NP to NP comparisons, intra-reader measurement differences ≥5 mm were seen for 3.7% (17/463) of masses <4 cm, but increased to 16.8% (20/119) for masses >4 cm (p < 0.0001). Masses with poorly defined margins (15.9% [22/138] vs. 3.4% [15/444] for well-defined margins, p < 0.0001) and heterogeneity (15.3% [22/144], vs. 5.0% [14/282] for minimally heterogeneous, vs. 0.6% [1/156] for homogeneous, p < 0.0001), were more frequently associated with measurement differences ≥5 mm. Differences ≥5 mm were more frequent when only CMP images were utilized (14% [42/299]), or when CMP images were compared with NP images (26% [77/299]). CONCLUSIONS: A ≥5 mm intra-reader variation in measured size of solid renal masses <4 cm is uncommon for NP to NP comparisons. Variation increases when masses are ≥4 cm, poorly defined, or heterogeneous; or when CMP images are utilized.