The Impact of an Unconventional Elective in Narrative Medicine and Pediatric Psycho-oncology on Humanism in Medical Students.

Over the course of medical school, students' optimism and hopefulness often devolve into a cynical view of medicine that continues throughout clinical rotations and beyond (Neumann et al., Acad Med 86(8):996-1009, 2011). Here, we present a qualitative evaluation of a novel immersive elective in pediatric psycho-oncology coupled with narrative medicine and its impact on students. Participants were third- and fourth-year medical students who were relieved of traditional clinical duties. Alternatively, they shadowed pediatric cancer patients, keeping narrative journals of their observations and insights. A trained team of pre-clinical medical students and faculty conducted a retrospective analysis of 120 journals written between 2008 and 2019. They compared recurring concepts to assess how blending experiential learning and reflective writing influenced the attitudes and behaviors of students. Consistent themes emerged related to developing a rich understanding of patient experiences, a humanistic appreciation of the context of illness, the ability to meaningfully reflect on insights to critically ill children, and an appreciation for the unique learning opportunity. Additionally, families expressed gratitude for the students' attentiveness to their emotional needs. By the conclusion of the elective, most students discovered that they had reignited their intrinsic empathic behaviors and were provided with beneficial insights that they believed would continue into future rotations. Experiential teaching methods paired with narrative reflection may be a valuable and therapeutic tool to learn the intricacies of the patient perspective, with the potential to enhance humanism in students during a critical time in their medical training when empathy tends to drift. Longitudinal and quantitative studies are warranted to better understand the degree and duration of specific benefits.

Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In-Phase and Opposed-Phase MRI?

OBJECTIVE: The purpose of this study is to determine whether second-order texture analysis can be used to distinguish lipid-poor adenomas from malignant adrenal nodules on unenhanced CT, contrast-enhanced CT (CECT), and chemical-shift MRI. MATERIALS AND METHODS: In this retrospective study, 23 adrenal nodules (15 lipid-poor adenomas and eight adrenal malignancies) in 20 patients (nine female patients and 11 male patients; mean age, 59 years [range, 15-80 years]) were assessed. All patients underwent unenhanced CT, CECT, and chemical-shift MRI. Twenty-one second-order texture features from the gray-level cooccurrence matrix and gray-level run-length matrix were calculated in 3D. The mean values for 21 texture features and four imaging features (lesion size, unenhanced CT attenuation, CECT attenuation, and signal intensity index) were compared using a t test. The diagnostic performance of texture analysis versus imaging features was also compared using AUC values. Multivariate logistic regression models to predict malignancy were constructed for texture analysis and imaging features. RESULTS: Lesion size, unenhanced CT attenuation, and the signal intensity index showed significant differences between benign and malignant adrenal nodules. No significant difference was seen for CECT attenuation. Eighteen of 21 CECT texture features and nine of 21 unenhanced CT texture features revealed significant differences between benign and malignant adrenal nodules. CECT texture features (mean AUC value, 0.80) performed better than CECT attenuation (mean AUC value, 0.60). Multivariate logistic regression models showed that CECT texture features, chemical-shift MRI texture features, and imaging features were predictive of malignancy. CONCLUSION: Texture analysis has a potential role in distinguishing benign from malignant adrenal nodules on CECT and may decrease the need for additional imaging studies in the workup of incidentally discovered adrenal nodules.

Comparison of Visualization Rates of LI-RADS Version 2014 Major Features With IV Gadobenate Dimeglumine or Gadoxetate Disodium in Patients at Risk for Hepatocellular Carcinoma.

OBJECTIVE: The purpose of this study is to compare visualization rates of the major features covered by Liver Imaging Reporting and Data System (LI-RADS) version 2014 in patients at risk for hepatocellular carcinoma using either gadobenate dimeglumine or gadoxetate disodium IV contrast agent. MATERIALS AND METHODS: This retrospective study included liver MRI examinations performed with either gadobenate dimeglumine or gadoxetate disodium contrast enhancement. Using age, sex, underlying liver disease, and presence of cirrhosis, patients were placed into matched cohorts. All hepatic nodules 1 cm or larger (up to five per subject) were included, resulting in 63 subjects with 130 nodules (median nodule size, 1.9 cm) imaged with gadobenate and 64 subjects with 117 nodules (median nodule size, 2.0 cm) imaged with gadoxetate. Three radiologists reviewed the studies for LI-RADS major features independently. Bootstrap resampling with 10,000 repetitions was used to compare feature detection rates. RESULTS: Arterial phase hyperenhancement was seen in a similar number of nodules with gadobenate dimeglumine (mean, 91.5% [119/130]) and gadoxetate disodium (mean, 88.0% [103/117]) (p = 0.173). Dynamic phase washout was more commonly seen with gadobenate dimeglumine (mean, 60.2% [78.3/130]) than with gadoxetate disodium (mean, 45.3% [53/117]) (p = 0.006). The capsule feature was more often visualized with gadobenate dimeglumine (mean, 50.2% [65.3/130]) than with gadoxetate disodium (mean, 33.3% [39/117]) (p < 0.001). Interreader agreement for arterial phase enhancement and dynamic phase washout was almost perfect for both contrast agents (κ > 0.83). Agreement for the capsule feature was moderate for gadobenate dimeglumine (κ = 0.52) and substantial for gadoxetate disodium (κ = 0.67). CONCLUSION: The rates of visualization of arterial phase hyperenhancement are similar in studies performed with gadobenate dimeglumine and gadoxetate disodium, but dynamic phase washout and capsule appearance are more commonly visualized with gadobenate dimeglumine.

Clinically Acceptable Optimized Dose Reduction in Computed Tomographic Imaging of Necrotizing Pancreatitis Using a Noise Addition Software Tool.

OBJECTIVE: This study aimed to determine potential radiation dose reduction of contrast-enhanced computed tomography (CECT) for imaging necrotizing pancreatitis (NP) using a noise addition tool. METHODS: Eighty-four patients were identified with at least 1 abdominopelvic CECT for NP within a 2-year period. Sixty consecutive scans were selected as reference radiation dose data sets. A noise addition software was used to simulate 4 data sets of increased noise. Readers rated confidence for identifying (i) anatomic structures, (ii) complications of NP, and (iii) diagnostic acceptability. Noise and dose levels were identified at acceptability threshold where observer scores were statistically indistinguishable from full-dose computed tomographies. RESULTS: Observers' perception of image tasks decreased progressively with increasing noise (P < 0.05). Acceptability and statistical analysis indicated that noise can be increased from 10 to 25 HU corresponding to an 84% reduction in dose without change in observer perception (P < 0.05). CONCLUSIONS: Higher image noise levels may be tolerated in CECT in patients with NP.

Dual-energy multidetector CT for the characterization of incidental adrenal nodules: diagnostic performance of contrast-enhanced material density analysis.

PURPOSE: To determine whether contrast material-enhanced dual-energy multidetector computed tomography (CT) with material decomposition analysis allows differentiation of adrenal adenomas from nonadenomatous lesions and to compare findings with those of nonenhanced multidetector CT. MATERIALS AND METHODS: This retrospective HIPAA-compliant study was approved by the institutional review board of Duke University, with waiver of informed consent. Thirty-eight nonconsecutive patients (22 men and 16 women; mean age, 65 years) with 47 adrenal nodules underwent nonenhanced and contrast-enhanced dual-energy multidetector CT of the abdomen. For each adrenal nodule, nonenhanced attenuation values were recorded; dual-energy density measurements were obtained by using fat-iodine and fat-water material density basis pairs. Mean and median values of nonenhanced attenuation and material densities were compared between adenomas and nonadenomas by using the two-sample t test and Wilcoxon rank sum test, respectively. The diagnostic performance of nonenhanced multidetector CT and dual-energy material densities was assessed by setting the specificity for diagnosis of adenomas at 100%. RESULTS: Adenomas (lipid rich and lipid poor) displayed significantly different mean density values (in milligrams per cubic centimeter) than those of nonadenomas on fat-iodine (970.4 ± 17.2 vs 1012.3 ± 9.3), iodine-fat (2.5 ± 0.3 vs 4.5 ± 1.5), fat-water (-666.7 ± 154.8 vs -2141.8 ± 953.2), and water-fat (1628.4 ± 177.3 vs 3225 ± 986.1) images, respectively (P < .0001). For diagnosis of adenomas, dual-energy material density analysis showed a sensitivity of 96% (23 of 24 lesions) at a specificity of 100% (23 of 23 lesions), yielding significantly improved diagnostic performance compared with nonenhanced multidetector CT attenuation (sensitivity of 67% [16 of 24 lesions] at a specificity of 100% [23 of 23 lesions]) (P = .035). CONCLUSION: Contrast-enhanced dual-energy multidetector CT with material density analysis allows differentiation between adrenal adenomas and nonadenomas, reflecting an improved ability over nonenhanced multidetector CT for diagnosis of lipid-poor adenoma.

Management of Anticoagulant and Antiplatelet Medications in Adults Undergoing Percutaneous Interventions.

OBJECTIVE: Many radiologists are unfamiliar with the new antithrombogenic medications and how to modify patient management before nonvascular percutaneous procedures performed in a radiology department. In this article, we review the indications for use, mechanism of action, pharmacokinetics, dosing, and recommendations for periprocedural management of patients using these medications. CONCLUSION: To improve patient safety, radiologists involved in percutaneous procedures should have knowledge of the antithrombotics that will be encountered routinely in clinical practice.

Diagnostic performance of imaging criteria for distinguishing autoimmune cholangiopathy from primary sclerosing cholangitis and bile duct malignancy.

OBJECTIVE: To determine the diagnostic performance of imaging criteria for distinguishing Ig-G4-associated autoimmune cholangiopathy (IAC) from primary sclerosing cholangitis (PSC) and bile duct malignancy. METHODS: A medical records search between January 2008 and October 2013 identified 10 patients (8 M, 2 F, mean age 61 years, range 34-82) with a clinical diagnosis of IAC. Fifteen cases of PSC (6 M, 9 F, mean age 50, range 22-65) and 15 cases of biliary malignancy (7 M, 8 F, mean age 65, range 48-84) were randomly selected for comparative analysis. Three abdominal radiologists independently reviewed MRI with MRCP (n = 32) or CT (n = 8) and ERCP (n = 8) for the following IAC imaging predictors: single-wall bile duct thickness >2.5 mm, continuous biliary involvement, gallbladder involvement, liver disease, peribiliary mass, or pancreatic and renal abnormalities. Each radiologist provided an imaging-based diagnosis (IAC, PSC, or cancer). Imaging predictor sensitivity, specificity, accuracy, and association with IAC using Fisher's exact test. Inter-reader agreement determined using Fleiss' kappa statistics. RESULTS: For diagnosis of IAC, sensitivities and specificities were high (70-93%). Pancreatic abnormality was strongest predictor for distinguishing IAC from PSC and cancer, with high diagnostic performance (70-80% sensitivity, 87-97% specificity), significant association (p < 0.01), and moderate inter-reader agreement (κ = 0.59). Continuous biliary involvement was moderately predictive (50-100% sensitivity, 53-83% specificity) and trended toward significant association in distinguishing from PSC (p = 0.01-0.19), but less from cancer (p = 0.06-0.62). CONCLUSION: It remains difficult to distinguish IAC from PSC or bile duct malignancy based on imaging features alone. The presence of pancreatic abnormalities, including peripancreatic rind, atrophy, abnormal enhancement, or T2 signal intensity, strongly favors a diagnosis of IAC.

Effect of radiologists' experience with an adaptive statistical iterative reconstruction algorithm on detection of hypervascular liver lesions and perception of image quality.

PURPOSE: To prospectively evaluate whether clinical experience with an adaptive statistical iterative reconstruction algorithm (ASiR) has an effect on radiologists' diagnostic performance and confidence for the diagnosis of hypervascular liver tumors, as well as on their subjective perception of image quality. MATERIALS AND METHODS: Forty patients, having 65 hypervascular liver tumors, underwent contrast-enhanced MDCT during the hepatic arterial phase. Image datasets were reconstructed with filtered backprojection algorithm and ASiR (20%, 40%, 60%, and 80% blending). During two reading sessions, performed before and after a three-year period of clinical experience with ASiR, three readers assessed datasets for lesion detection, likelihood of malignancy, and image quality. RESULTS: For all reconstruction algorithms, there was no significant change in readers' diagnostic accuracy and sensitivity for the detection of liver lesions, between the two reading sessions. However, a 60% ASiR dataset yielded a significant improvement in specificity, lesion conspicuity, and confidence for lesion likelihood of malignancy during the second reading session (P < 0.0001). The 60% ASiR dataset resulted in significant improvement in readers' perception of image quality during the second reading session (P < 0.0001). CONCLUSIONS: Clinical experience using an ASiR algorithm may improve radiologists' diagnostic performance for the diagnosis of hypervascular liver tumors, as well as their perception of image quality.

Impact of medicine shortages on hospital practice: role of a multidisciplinary medicine shortages team.

Medicine shortages are an increasing issue, with broad public health implications for patients, health professionals and institutions. Despite national notification mechanisms involving sponsors and national regulators (e.g. Australian Therapeutic Goods Administration), shortages continue to be a significant workload in hospitals, particularly for pharmacy staff. In this article, we describe the implications of medicine shortages and a team approach to their management in an Australian public hospital. The medicine shortages team comprises senior pharmacists, a pharmacy technician, and a purchasing officer, in consultation with medical staff. A 10 week audit recorded 34 medicine shortages and/or discontinuations, comprising 49 usually stocked products. Shortages were more quickly identified by the purchasing officer using established relationships with suppliers, rather than relying on sponsor or government communication. Having a team systematically dealing with these shortages enables expertise in supply chains, finances, therapeutics, and medicine safety to be shared, to identify optimal interventions to mitigate patient risk.

Increasing utilization of contrast-enhanced ultrasound during abdominal biopsies: impact of an educational training program.

RATIONAL AND OBJECTIVES: To increase utilization of contrast-enhanced ultrasound (CEUS) during ultrasound-guided targeted liver biopsies. MATERIAL AND METHODS: Two educational training interventions performed to increase use of CEUS. First, 14 radiologists (fellowship-trained in Abdominal Imaging) given didactic teaching and case presentations on the use of CEUS. Second, hands-on teaching on how to use CEUS provided to the same group. To determine the efficacy of these two interventions, radiologists completed anonymous surveys to determine the level of understanding and acceptability of using CEUS before and 6 months after CEUS training. In addition, the percentage of CEUS assisted liver biopsies was compared for the 6 months before and 6 months after the training. RESULTS: Pre-training survey completed by 11 radiologists and post-training survey completed by 9 radiologists. Before training, 11% survey responders use CEUS routinely, whereas 89% never or rarely used it. After training, 54% of respondents were new users and 100% reported they planned to use CEUS in the future. Unfamiliarity (71%) was the main reason for not using it. After training, 25% reported lack of comfort with using CEUS as the main reason for not using CEUS. During six months before training, CEUS was administered in 6% (10/172) of targeted liver biopsies. Six months after training, CEUS was used nearly twice as often (10%, 16/160, P = 0.09, 1-sided Boschloo test). The number of radiologists using CEUS increased to 57% (8/14) after training compared to 20% (3/14, P = 0.03, 1-sided Boschloo) before training. CONCLUSION: Educational training intervention increases use of CEUS during ultrasound-guided targeted liver biopsies.

Simplifying risk stratification for thyroid nodules on ultrasound: validation and performance of an artificial intelligence thyroid imaging reporting and data system.

PURPOSE: To validate the performance of a recently created risk stratification system (RSS) for thyroid nodules on ultrasound, the Artificial Intelligence Thyroid Imaging Reporting and Data System (AI TI-RADS). MATERIALS AND METHODS: 378 thyroid nodules from 320 patients were included in this retrospective evaluation. All nodules had ultrasound images and had undergone fine needle aspiration (FNA). 147 nodules were Bethesda V or VI (suspicious or diagnostic for malignancy), and 231 were Bethesda II (benign). Three radiologists assigned features according to the AI TI-RADS lexicon (same categories and features as the American College of Radiology TI-RADS) to each nodule based on ultrasound images. FNA recommendations using AI TI-RADS and ACR TI-RADS were then compared and sensitivity and specificity for each RSS were calculated. RESULTS: Across three readers, mean sensitivity of AI TI-RADS was lower than ACR TI-RADS (0.69 vs 0.72, p < 0.02), while mean specificity was higher (0.40 vs 0.37, p < 0.02). Overall total number of points assigned by all three readers decreased slightly when using AI TI-RADS (5,998 for AI TI-RADS vs 6,015 for ACR TI-RADS), including more values of 0 to several features. CONCLUSION: AI TI-RADS performed similarly to ACR TI-RADS while eliminating point assignments for many features, allowing for simplification of future TI-RADS versions.

Hepatocellular carcinoma in a North American population: does hepatobiliary MR imaging with Gd-EOB-DTPA improve sensitivity and confidence for diagnosis?

PURPOSE: To evaluate the value of hepatobiliary phase imaging for detection and characterization of hepatocellular carcinoma (HCC) in liver MRI with Gd-EOB-DTPA, in a North American population. MATERIALS AND METHODS: One hundred MRI examinations performed with the intravenous injection of Gd-EOB-DTPA in patients with cirrhosis were reviewed retrospectively. Nodules were classified as HCC (n = 70), indeterminate (n = 33), or benign (n = 22). Five readers independently reviewed each examination with and without hepatobiliary phase images (HBP). Lesion conspicuity scores were compared between the two readings. Lesion detection, confidence scores, and receiver operating characteristic (ROC) analysis were compared. RESULTS: Lesion detection was slightly improved for all lesion types with the inclusion of the HBP, and was substantially higher for small HCCs (96.0% versus 85.3%). Mean confidence scores for the diagnosis of HCC increased for HCCs overall and each size category (P < 0.001). Diagnostic performance improved with the addition of the HBP (aggregate AROC 87.7% versus 80.0%, P < 0.01), and sensitivity for characterization improved (90.9% versus 78.3%, P < 0.01) while specificity was unchanged. CONCLUSION: Hepatobiliary phase imaging may improve small lesion detection (<1 cm) and characterization of lesions in general, in MRI of the cirrhotic liver with Gd-EOB-DTPA.

Clinical impact of an adaptive statistical iterative reconstruction algorithm for detection of hypervascular liver tumours using a low tube voltage, high tube current MDCT technique.

OBJECTIVES: To investigate the impact of an adaptive statistical iterative reconstruction (ASiR) algorithm on diagnostic accuracy and confidence for the diagnosis of hypervascular liver tumours, as well as the reader's perception of image quality, using a low tube voltage (80 kVp), high tube current computed tomography (CT) technique. METHODS: Forty patients (29 men, 11 women) with 65 hypervascular liver tumours underwent dual energy CT. The 80 kV set of the dual energy acquisition was reconstructed with standard filtered backprojection (FBP) and ASiR at different blending levels. Lesion contrast-to-noise ratio (CNR), reader's confidence for lesion detection and characterisation, and reader's evaluation of image quality were recorded. RESULTS: ASiR yielded significantly higher CNR values compared with FBP (P < 0.0001 for all comparisons). Reader's perception of lesion conspicuity and confidence in the diagnosis of malignancy were also higher with 60 % and 80 % ASiR, compared with FBP (P = 0.01 and < 0.001, respectively). Compared with FBP, ASiR yielded nearly significantly lower specificity for lesion detection and a substantial decrease in the reader's perception of image quality. CONCLUSIONS: Compared with the standard FBP algorithm, ASiR significantly improves conspicuity of hypervascular liver lesions. This improvement may come at the cost of decreased specificity and reader's perception of image quality.

The incarcerated uterus: a review of MRI and ultrasound imaging appearances.

OBJECTIVE: The objective of this article is to review the MRI and ultrasound appearances of incarcerated uterus. CONCLUSION: Incarcerated uterus is a rare but serious complication of pregnancy in which the gravid uterus becomes trapped in the posterior pelvis. Characteristic MRI and ultrasound imaging features enable definitive diagnosis of incarcerated uterus, which reduces risks of complications that can lead to maternal and fetal morbidity and mortality.

Multiphase multi-detector row computed tomography in the setting of chronic liver disease and orthotopic liver transplantation: can a series be eliminated in order to reduce radiation dose?

OBJECTIVE: The objectives of this study were to explore utilization of multi-detector row computed tomography (MDCT) in screening for hepatocellular carcinoma (HCC) and to modify a liver CT protocol with a goal of dose reduction. METHODS: An electronic mail survey querying HCC surveillance practices was sent. One hundred forty consecutive patients referred for HCC indications underwent 4-phase MDCT of the liver. The unenhanced and delayed phases were evaluated by 3 readers for identification of HCC and reader confidence. The estimated effective dose (ED) was calculated. RESULTS: Computed tomography is primarily used to screen for HCC. Average estimated ED was 35.5 mSv. Unenhanced phase did not add to reader confidence; delayed phase increased confidence in 47% of cases. Thirty-two percent of the screening population had cumulative ED of greater than 200 mSv. CONCLUSIONS: Multi-detector row CT of the liver is used frequently in screening for HCC. Unenhanced phase imaging does not add to HCC detection and may be eliminated to reduce radiation dose.

Deep learning for classification of thyroid nodules on ultrasound: validation on an independent dataset.

OBJECTIVES: The purpose is to apply a previously validated deep learning algorithm to a new thyroid nodule ultrasound image dataset and compare its performances with radiologists. METHODS: Prior study presented an algorithm which is able to detect thyroid nodules and then make malignancy classifications with two ultrasound images. A multi-task deep convolutional neural network was trained from 1278 nodules and originally tested with 99 separate nodules. The results were comparable with that of radiologists. The algorithm was further tested with 378 nodules imaged with ultrasound machines from different manufacturers and product types than the training cases. Four experienced radiologists were requested to evaluate the nodules for comparison with deep learning. RESULTS: The Area Under Curve (AUC) of the deep learning algorithm and four radiologists were calculated with parametric, binormal estimation. For the deep learning algorithm, the AUC was 0.69 (95% CI: 0.64-0.75). The AUC of radiologists were 0.63 (95% CI: 0.59-0.67), 0.66 (95% CI:0.61-0.71), 0.65 (95% CI: 0.60-0.70), and 0.63 (95%CI: 0.58-0.67). CONCLUSION: In the new testing dataset, the deep learning algorithm achieved similar performances with all four radiologists. The relative performance difference between the algorithm and the radiologists is not significantly affected by the difference of ultrasound scanner.

Dual-energy CT applications in the abdomen.

OBJECTIVE: The purpose of this article is to give a brief overview of the technical background of dual-energy CT (DECT) imaging and to review various DECT applications in the abdomen that are currently available for clinical practice. In a review of the recent literature, specific DECT applications available for abdominal organs, liver, pancreas, kidneys including renal stones, and adrenal glands, will be discussed in light of reliability and clinical usefulness in replacing true unenhanced imaging, increased lesion conspicuity, iodine extraction, and improved tissue/material characterization (e.g., renal stone composition). Radiation dose considerations will be addressed in comparison with standard abdominal imaging protocols. CONCLUSION: Modern DECT applications for the abdomen expand the use of CT and enable advanced quantitative methods in the clinical routine on the basis of differences in material attenuation observed by imaging at two different distinct photon energies.

Histogram analysis of small solid renal masses: differentiating minimal fat angiomyolipoma from renal cell carcinoma.

OBJECTIVE: The objective of our study was to retrospectively determine whether minimal fat renal angiomyolipoma can be differentiated from clear cell or papillary renal cell carcinoma (RCC) in small renal masses using attenuation measurement histogram analysis on unenhanced CT. MATERIALS AND METHODS: Twenty minimal fat renal angiomyolipomas were compared with 22 clear cell RCCs and 23 papillary RCCs using an institutional database. All masses were histologically confirmed and all minimal fat renal angiomyolipomas lacked radiographic evidence of macroscopic fat. Using attenuation measurement histogram analysis, two blinded radiologists determined the percentage of negative pixels within each renal mass. The percentages of negative pixels below attenuation thresholds of 0, -5, -10, -15, -20, -25, and -30 HU were recorded. Sensitivity, specificity, positive predictive value, negative predictive value, and receiver operator characteristic curves for the diagnosis of minimal fat renal angiomyolipoma were generated for each threshold. The Student t test was used to compare radiologists and cohorts. Previously published attenuation and pixel-counting thresholds reported as having a specificity of near 100% for discriminating between minimal fat renal angiomyolipomas and RCCs were analyzed. RESULTS: The mean maximal transverse lesion diameter was 1.8 cm for minimal fat renal angiomyolipomas (SD, 0.5 cm; range, 1.1-3.0 cm), 2.1 cm for clear cell RCCs (SD, 0.5 cm; range, 1.0-2.9 cm), and 2.1 cm for papillary RCCs (SD, 0.7 cm; range, 1.3-3.9 cm). No significant difference in the percentage of negative pixels was found between minimal fat renal angiomyolipomas and clear cell RCCs or between minimal fat renal angiomyolipomas and papillary RCCs at any of the selected attenuation thresholds for either radiologist (p = 0.210-0.499). Radiologist 1 and radiologist 2 used significantly different region-of-interest sizes (p < 0.001), but neither radiologist could differentiate minimal fat renal angiomyolipoma from RCC. No previously published threshold allowed discrimination between minimal fat renal angiomyolipoma and RCC with 100% specificity. CONCLUSION: Attenuation measurement histogram analysis cannot reliably differentiate minimal fat renal angiomyolipoma from RCC.

Characterization of adrenal nodules with dual-energy CT: can virtual unenhanced attenuation values replace true unenhanced attenuation values?

OBJECTIVE: The purpose of our study was to investigate whether virtual unenhanced adrenal nodule attenuation values can replace true noncontrast attenuation values. MATERIALS AND METHODS: Twenty-three incidentally discovered adrenal nodules (19 adenomas and four metastases) were identified in 19 patients (11 men and eight women; mean age, 65 years; age range, 38-84 years) who underwent unenhanced single-energy CT followed by contrast-enhanced dual-energy CT on the same scanner. A virtual unenhanced imaging dataset was generated from each dual-energy CT dataset. CT attenuation of each adrenal nodule was measured at the same location on virtual unenhanced images and true unenhanced images by three radiologists and mean values compared using the Student t test. Correlation between virtual unenhanced and true unenhanced values was determined using linear regression analysis. The mean difference and percentage of diagnostic agreement were also determined. Interreader variability was assessed using the intraclass correlation coefficient (ICC). RESULTS: The mean ± SD attenuation values for virtual unenhanced images and true unenhanced images were 14.7 ± 15.1 HU and 12.9 ± 13.4 HU, respectively (p = 0.2). Strong positive correlation was observed between virtual unenhanced images and true unenhanced images (R = 0.83-0.87). The mean difference between virtual unenhanced images and true unenhanced images was 1.8 ± 1.7 HU. Diagnostic agreement between virtual unenhanced images and true unenhanced images was 83-91% for three radiologists. No malignant nodules were misclassified as benign on virtual unenhanced images. The ICC was 0.88 and 0.96 for virtual unenhanced images and true unenhanced images, respectively, indicating high interreader agreement. CONCLUSION: Virtual unenhanced and true unenhanced attenuation measurements of adrenal nodules were not significantly different and showed strongly positive linear correlation. This finding resulted in substantial diagnostic agreement between virtual unenhanced images and true unenhanced images for distinguishing benign from malignant nodules.

Biochemical effects of phosphate-containing replacement fluid for continuous venovenous hemofiltration.

AIMS: To examine biochemical effects of phosphate-containing replacement fluid (Phoxilium(®)) for continuous venovenous hemofiltration (CVVH). METHODS: Retrospective comparison of respective serum biochemistry with sequential use of Accusol™ and Phoxilium, each over 48 h of CVVH. RESULTS: We studied 15 critically ill patients. Accusol was switched to Phoxilium after 5 (4-8) days of CVVH. Respective serum biochemistry after 36-42 h of Accusol versus Phoxilium were: phosphate 1.02 (0.82-1.15) versus 1.44 (1.23-1.78) mmol/l, ionized calcium 1.28 (1.22-1.32) versus 1.12 (1.06-1.21) mmol/l, bicarbonate 24 (23-25) versus 20 (19-22) mmol/l, base excess 0 (-2 to 1) versus -4 (-6 to -3) mmol/l (p < 0.001). Cumulative phosphate intakes during respective periods were 69.6 (56.6-76.6) versus 67.2 (46.6-79.0) mmol (p = 0.45). Plasma strong ion differences were narrower with Phoxilium (p < 0.05), with similar strong ion gaps. No additional intravenous phosphate was given during Phoxilium use. Seven patients had serum phosphate >1.44 mmol/l. CONCLUSIONS: Phoxilium versus Accusol use during CVVH effectively prevented hypophosphatemia but contributed to mild hyperphosphatemia, and is associated with relative hypocalcemia and metabolic acidosis.