MRI Extracellular Volume Fraction in Liver Fibrosis-A Comparison of Different Time Points and Blood Pool Measurements.

BACKGROUND: Extracellular volume (ECV) correlates with the degree of liver fibrosis. PURPOSE: To analyze the performance of liver MRI-based ECV evaluations with different blood pool measurements at different time points. STUDY TYPE: Prospective. SAMPLE: 73 consecutive patients (n = 31 females, mean age 56 years) with histopathology-proven liver fibrosis. FIELD STRENGTH/SEQUENCE: 3T acquisition within 90 days of biopsy, including shortened modified look-locker inversion recovery T1 mapping. ASSESSMENT: Polygonal regions of interest were manually drawn in the liver, aorta, vena cava, and in the main, left and right portal vein on four slices before and after Gd-DOTA administration at 5/10/15 minutes. ECV was calculated 1) on one single slice on portal bifurcation level, and 2) averaged over all four slices. STATISTICAL TESTS: Parameters were compared between patients with fibrosis grades F0-2 and F3-F4 with the Mann-Whitney U and fishers exact test. ROC analysis was used to assess the performance of the parameters to predict F3-4 fibrosis. A P-value <0.05 was considered statistically significant. RESULTS: ECV was significantly higher in F3-4 fibrosis (35.4% [33.1%-37.6%], 36.1% [34.2%-37.5%], and 37.0% [34.8%-39.2%] at 5/10/15 minutes) than in patients with F0-2 fibrosis (33.3% [30.8%-34.8%], 33.7% [31.6%-34.7%] and 34.9% [32.2%-36.0%]; AUC = 0.72-0.75). Blood pool T1 relaxation times in the aorta and vena cava were longer on the upper vs. lower slices at 5 minutes, but not at 10/15 minutes. AUC values were similar when measured on a single slice (AUC = 0.69-0.72) or based on blood pool measurements in the cava or portal vein (AUC = 0.63-0.67 and AUC = 0.65-0.70). DATA CONCLUSION: Liver ECV is significantly higher in F3-4 fibrosis compared to F0-2 fibrosis with blood pool measurements performed in the aorta, inferior vena cava, and portal vein at 5, 10, and 15 minutes. However, a smaller variability was observed for blood pool measurements between slices at 15 minutes. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY: Stage 3.

Influence of CT dose reduction on AI-driven malignancy estimation of incidental pulmonary nodules.

OBJECTIVES: The purpose of this study was to determine the influence of dose reduction on a commercially available lung cancer prediction convolutional neuronal network (LCP-CNN). METHODS: CT scans from a cohort provided by the local lung cancer center (n = 218) with confirmed pulmonary malignancies and their corresponding reduced dose simulations (25% and 5% dose) were subjected to the LCP-CNN. The resulting LCP scores (scale 1-10, increasing malignancy risk) and the proportion of correctly classified nodules were compared. The cohort was divided into a low-, medium-, and high-risk group based on the respective LCP scores; shifts between the groups were studied to evaluate the potential impact on nodule management. Two different malignancy risk score thresholds were analyzed: a higher threshold of ≥ 9 ("rule-in" approach) and a lower threshold of > 4 ("rule-out" approach). RESULTS: In total, 169 patients with 196 nodules could be included (mean age ± SD, 64.5 ± 9.2 year; 49% females). Mean LCP scores for original, 25% and 5% dose levels were 8.5 ± 1.7, 8.4 ± 1.7 (p > 0.05 vs. original dose) and 8.2 ± 1.9 (p < 0.05 vs. original dose), respectively. The proportion of correctly classified nodules with the "rule-in" approach decreased with simulated dose reduction from 58.2 to 56.1% (p = 0.34) and to 52.0% for the respective dose levels (p = 0.01). For the "rule-out" approach the respective values were 95.9%, 96.4%, and 94.4% (p = 0.12). When reducing the original dose to 25%/5%, eight/twenty-two nodules shifted to a lower, five/seven nodules to a higher malignancy risk group. CONCLUSION: CT dose reduction may affect the analyzed LCP-CNN regarding the classification of pulmonary malignancies and potentially alter pulmonary nodule management. CLINICAL RELEVANCE STATEMENT: Utilization of a "rule-out" approach with a lower malignancy risk threshold prevents underestimation of the nodule malignancy risk for the analyzed software, especially in high-risk cohorts. KEY POINTS: • LCP-CNN may be affected by CT image parameters such as noise resulting from low-dose CT acquisitions. • CT dose reduction can alter pulmonary nodule management recommendations by affecting the outcome of the LCP-CNN. • Utilization of a lower malignancy risk threshold prevents underestimation of pulmonary malignancies in high-risk cohorts.

Minor head trauma in infants - how accurate is cranial ultrasound performed by trained radiologists?

Correct management of infants after minor head trauma is crucial to minimize the risk to miss clinically important traumatic brain injury (ciTBI). Current practices typically involve CT or in-hospital surveillance. Cranial ultrasound (CUS) provides a radiation-free and fast alternative. This study examines the accuracy of radiologist-performed CUS to detect skull fracture (SF) and/or intracranial hemorrhage (ICH). An inconspicuous CUS followed by an uneventful clinical course would allow exclusion of ciTBI with a great certainty. This monocentric, retrospective, observational study analyzed CUS in infants (< 12 months) after minor head trauma at Bern University Children's Hospital, between 7/2013 and 8/2020. The primary outcome was the sensitivity and specificity of CUS in detecting SF and/or ICH by comparison to the clinical course and to additional neuroimaging. Out of a total of 325 patients, 73% (n = 241) had a normal CUS, 17% (n = 54) were found with SF, and ICH was diagnosed in 2.2% patients (n = 7). Two patients needed neurosurgery and three patients deteriorated clinically during surveillance. Additional imaging was performed in 35 patients. The sensitivity of CUS was 93% ([0.83, 0.97] 95% CI) and the specificity 98% ([0.95, 0.99] 95% CI). All false-negative cases originated in missed SF without clinical deterioration; no ICH was missed.  Conclusion: This study shows high accuracy of CUS in exclusion of SF and ICH, which can cause ciTBI. Therefore, CUS offers a reliable method of neuroimaging in infants after minor head trauma and gives reassurance to reduce the duration of in-hospital surveillance. What is Known: • Minor head trauma can cause clinically important traumatic brain injury in infants, and the management of these cases is a challenge for the treating physician. • Cranial ultrasound (CUS) is regularly used in neonatology, but its accuracy after head trauma in infants is controversial. What is New: • CUS performed by a trained radiologist can exclude findings related to clinically important traumatic brain injury (ciTBI) with high sensitivity and specificity. It therefore offers reassurance in the management of infants after minor head trauma.

MRI Shows Lung Perfusion Changes after Vaping and Smoking.

Background Evidence regarding short-term effects of electronic nicotine delivery systems (ENDS) and tobacco smoke on lung ventilation and perfusion is limited. Purpose To examine the immediate effect of ENDS exposure and tobacco smoke on lung ventilation and perfusion by functional MRI and lung function tests. Materials and Methods This prospective observational pilot study was conducted from November 2019 to September 2021 (substudy of randomized controlled trial NCT03589989). Included were 44 healthy adult participants (10 control participants, nine former tobacco smokers, 13 ENDS users, and 12 active tobacco smokers; mean age, 41 years ± 12 [SD]; 28 men) who underwent noncontrast-enhanced matrix pencil MRI and lung function tests before and immediately after the exposure to ENDS products or tobacco smoke. Baseline measurements were acquired after 2 hours of substance abstinence. Postexposure measurements were performed immediately after the exposure. MRI showed semiquantitative measured impairment of lung perfusion (RQ) and fractional ventilation (RFV) impairment as percentages of affected lung volume. Lung clearance index (LCI) was assessed by nitrogen multiple-breath washout to capture ventilation inhomogeneity and spirometry to assess airflow limitation. Absolute differences were calculated with paired Wilcoxon signed-rank test and differences between groups with unpaired Mann-Whitney test. Healthy control participants underwent two consecutive MRI measurements to assess MRI reproducibility. Results MRI was performed and lung function measurement was acquired in tobacco smokers and ENDS users before and after exposure. MRI showed a decrease of perfusion after exposure (RQ, 8.6% [IQR, 7.2%-10.0%] to 9.1% [IQR, 7.8%-10.7%]; P = .03) and no systematic change in RFV (P = .31) among tobacco smokers. Perfusion increased in participants who used ENDS after exposure (RQ, 9.7% [IQR, 7.1%-10.9%] to 9.0% [IQR, 6.9%-10.0%]; P = .01). RFV did not change (P = .38). Only in tobacco smokers was LCI elevated after smoking (P = .02). Spirometry indexes did not change in any participants. Conclusion MRI showed a decrease of lung perfusion after exposure to tobacco smoke and an increase of lung perfusion after use of electronic nicotine delivery systems. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Kligerman in this issue.

Diagnostic validation of a deep learning nodule detection algorithm in low-dose chest CT: determination of optimized dose thresholds in a virtual screening scenario.

OBJECTIVES: This study was conducted to evaluate the effect of dose reduction on the performance of a deep learning (DL)-based computer-aided diagnosis (CAD) system regarding pulmonary nodule detection in a virtual screening scenario. METHODS: Sixty-eight anthropomorphic chest phantoms were equipped with 329 nodules (150 ground glass, 179 solid) with four sizes (5 mm, 8 mm, 10 mm, 12 mm) and scanned with nine tube voltage/current combinations. The examinations were analyzed by a commercially available DL-based CAD system. The results were compared by a comparison of proportions. Logistic regression was performed to evaluate the impact of tube voltage, tube current, nodule size, nodule density, and nodule location. RESULTS: The combination with the lowest effective dose (E) and unimpaired detection rate was 80 kV/50 mAs (sensitivity: 97.9%, mean false-positive rate (FPR): 1.9, mean CTDIvol: 1.2 ± 0.4 mGy, mean E: 0.66 mSv). Logistic regression revealed that tube voltage and current had the greatest impact on the detection rate, while nodule size and density had no significant influence. CONCLUSIONS: The optimal tube voltage/current combination proposed in this study (80 kV/50 mAs) is comparable to the proposed combinations in similar studies, which mostly dealt with conventional CAD software. Modification of tube voltage and tube current has a significant impact on the performance of DL-based CAD software in pulmonary nodule detection regardless of their size and composition. KEY POINTS: • Modification of tube voltage and tube current has a significant impact on the performance of deep learning-based CAD software. • Nodule size and composition have no significant impact on the software's performance. • The optimal tube voltage/current combination for the examined software is 80 kV/50 mAs.

Full core technology versus notch sampling technology: evaluation of the diagnostic accuracy and the risk of a pneumothorax after transthoracic needle biopsy of suspicious lung lesions.

BACKGROUND: Percutaneous needle biopsy of the lung (PCBL) under image guidance has become a safe and effective minimal invasive method to obtain a specimen related histological diagnosis of pulmonary lesions. PURPOSE: To evaluate the diagnostic yield and safety of two different coaxial biopsy technologies: full core and notch sampling technology. The former allowing the removal of full punch cylinders and the latter using a cutting-edge mechanism. MATERIAL AND METHODS: A retrospective analysis of 48 consecutive PCBL procedures has been carried out for this prognostic study, involving patients with a documented pulmonary nodule or mass lesion on previous computed tomography (CT) scans. The study population included 38 men and 10 women (mean age = 67 years). Of these 48 patients who underwent a procedure with a co-axial cutting system, 24 have been performed with notch sampling technology and 24 with full core technology. RESULTS: Out of the 48 biopsy procedures, 46 yielded specimens were adequate for histopathological evaluation, consistent with a technical success rate of 96%. The most common induced image-guided biopsy complication was a pneumothorax, occurring in 14 patients (35%). Seven patients with a pneumothorax were attributed to the full core technology and seven to the notch sampling technology (odds ratio = 1, 95% confidence interval = 0.28-3.51, P = 1). CONCLUSION: In the setting of full core versus notch sampling percutaneous CT-guided coaxial needle biopsy of the lung, no significant difference in the diagnostic accuracy and the incidence of pneumothoraces could be shown, while both technologies have an excellent diagnostic performance.

Ionic and non-ionic intravenous X-ray contrast media: antibacterial agents?

X-ray contrast media have been reported to have inhibitory effects on bacterial growth. Despite its potentially beneficial effect on patients, these features of contrast media have received relatively little attention in the medical literature in the past decades. The aim of this review is to evaluate the literature concerning the bactericidal and bacteriostatic effects of X-ray contrast media, specifically if there is a known difference concerning these effects between ionic and non-ionic contrast media. Systematic literature review was performed for the years of publication between 1911 and 2019. Since the publication of Grossich in 1911, the effect of iodine on the treatment of superficial infections in surgical procedures has been established clinical knowledge. Bacteriostatic and bactericidal effects of ionic X-ray contrast media are well established. However, non-ionic contrast agents have been the subject of little research in this respect. In past decades, the hypothesis emerged in the literature that mainly the concentration of free iodine might be responsible for any bacteriostatic or bactericidal effect of ionic X-ray contrast media. Nowadays, however, only non-ionic contrast media are used. The question regarding the mechanism and magnitude of bacteriostatic or bactericidal effects of these, non-ionic contrast media, could not be answered conclusively from this review. Non-ionic contrast media could be used intentionally when a local antibacterial effect is intended (e.g. in percutaneous abscess drainage), as well as to reduce the overall dose of antibiotics administered to a patient. Thus, this question remains relevant and might constitute the area of future research.

Influence of Clinical Expertise Between Clinician-Instructors Versus Student-Instructors on the Effectiveness of Ultrasound Courses.

PURPOSE: To investigate how the extent of an ultrasound instructor's clinical expertise influences the level of hands-on ultrasound competency achieved by clinicians after three-day ultrasound courses in abdominal and emergency ultrasound. The second goal was to determine how physicians in residency rate the sonographic and didactic skills of student instructors compared to medical staff instructors. METHOD: A total of N = 100 residents participating in a 3-day ultrasound workshop were randomly trained either by 15 student instructors or by clinical staff physicians, both with > 2 years of teaching experience. Both instructor groups had previously completed 120 hours of didactic instructor training. Ultrasound competencies were assessed by a standardized objective structured clinical examination (OSCE) of healthy individuals. The sonographic and didactic skills of both instructor groups were rated by questionnaires with six-step Likert items (1 = excellent, 6 = poor). RESULTS: The cohort, trained by student instructors, achieved the same scoring level as the second cohort, trained by physician instructors (mean score 76.4, versus 73.7 of max. 100 points, p = 0.28) in the final OSCE. The sonographic qualification was rated for student educators as 1.44 (mean) [1.1-1.62], versus residents 1.46 [1.26-1.61], versus attendings 1.29 [1.05-1.61]. Didactic skill levels were rated without significant differences with means of 1.53, 1.57 and 1.53, respectively. DISCUSSION & CONCLUSION: The didactic competence of student instructors does not differ statistically from the competency levels of experienced physicians. In terms of the acquired ultrasound skills of trainees, our data indicate that student instructors can be as efficient as staff instructors. Therefore, student instructors can be employed as resource-saving ultrasound educators without decreasing the skills level achieved by course participants, provided that they previously underwent a comprehensive didactic and sonographic training program.

A comprehensive review of imaging findings in COVID-19 - status in early 2021.

Medical imaging methods are assuming a greater role in the workup of patients with COVID-19, mainly in relation to the primary manifestation of pulmonary disease and the tissue distribution of the angiotensin-converting-enzyme 2 (ACE 2) receptor. However, the field is so new that no consensus view has emerged guiding clinical decisions to employ imaging procedures such as radiography, computer tomography (CT), positron emission tomography (PET), and magnetic resonance imaging, and in what measure the risk of exposure of staff to possible infection could be justified by the knowledge gained. The insensitivity of current RT-PCR methods for positive diagnosis is part of the rationale for resorting to imaging procedures. While CT is more sensitive than genetic testing in hospitalized patients, positive findings of ground glass opacities depend on the disease stage. There is sparse reporting on PET/CT with [18F]-FDG in COVID-19, but available results are congruent with the earlier literature on viral pneumonias. There is a high incidence of cerebral findings in COVID-19, and likewise evidence of gastrointestinal involvement. Artificial intelligence, notably machine learning is emerging as an effective method for diagnostic image analysis, with performance in the discriminative diagnosis of diagnosis of COVID-19 pneumonia comparable to that of human practitioners.

T1 mapping of the liver and the spleen in patients with liver fibrosis-does normalization to the blood pool increase the predictive value?

PURPOSE: To analyze whether the T1 relaxation time of the liver is a good predictor of significant liver fibrosis and whether normalization to the blood pool improves the predictive value. METHODS: This prospective study was conducted between 03/2016 and 02/2018. One hundred seventy-three patients underwent multiparametric liver MRI at 3 T. The T1 relaxation time was measured in the liver and the spleen, in the aorta, the portal vein, and the inferior vena cava (IVC). T1 relaxation times with and without normalization to the blood pool were compared between patients with (n = 26) and without (n = 141) significant liver fibrosis, based on a cutoff value of 3.5 kPa in MRE as the noninvasive reference standard. For statistics, Student's t test, receiver operating characteristic (ROC) curve analysis, and Pearson's correlation were used. RESULTS: The T1 relaxation time of the liver was significantly longer in patients with liver fibrosis, both with and without blood pool normalization (p < 0.001). T1 relaxation time of the liver allowed prediction of significant liver fibrosis (AUC = 0.88), while normalization to the IVC resulted in a slightly lower performance (AUC = 0.82). The lowest performance was achieved when the T1 relaxation times of the liver were normalized to the aorta (AUC = 0.66) and to the portal vein (AUC = 0.62). The T1 relaxation time of the spleen detected significant liver fibrosis with an AUC of 0.68, and 0.51-0.64 with normalization to the blood pool. CONCLUSION: The T1 relaxation time of the liver is a good predictor of significant liver fibrosis. However, normalization of the blood pool did not improve the predictive value. KEY POINTS: • The T1 relaxation time of the liver is a good predictor of significant liver fibrosis. • Normalization to the blood pool did not improve the predictive value of T1 mapping. • If the blood pool normalization was weighted 30% to the aorta and 70% to the portal vein, the performance was better than normalization to the aorta alone but still lower than normalization to the IVC.

CT perfusion in peripheral arterial disease-hemodynamic differences before and after revascularisation.

OBJECTIVES: The purpose of this study was the assessment of volumetric CT perfusion (CTP) of the lower leg musculature in patients with symptomatic peripheral arterial disease (PAD) before and after interventional revascularisation. METHODS: Twenty-nine consecutive patients with symptomatic PAD of the lower extremities requiring interventional revascularisation were assessed prospectively. All patients underwent a CTP scan of the lower leg, and hemodynamic and angiographic assessment, before and after intervention. Ankle-brachial pressure index (ABI) was determined. CTP parameters were calculated with a perfusion software, acting on a no outflow assumption. A sequential two-compartment model was used. Differences in CTP parameters were assessed with non-parametric tests. RESULTS: The cohort consisted of 24 subjects with an occlusion, and five with a high-grade stenosis. The mean blood flow before/after (BFpre and BFpost, respectively) was 7.42 ± 2.66 and 10.95 ± 6.64 ml/100 ml*min-1. The mean blood volume before/after (BVpre and BVpost, respectively) was 0.71 ± 0.35 and 1.25 ± 1.07 ml/100 ml. BFpost and BVpost were significantly higher than BFpre and BVpre in the treated limb (p = 0.003 and 0.02, respectively), but not in the untreated limb (p = 0.641 and 0.719, respectively). CONCLUSIONS: CTP seems feasible for assessing hemodynamic differences in calf muscles before and after revascularisation in patients with symptomatic PAD. We could show that CTP parameters BF and BV are significantly increased after revascularisation of the symptomatic limb. In the future, this quantitative method might serve as a non-invasive method for surveillance and therapy control of patients with peripheral arterial disease. KEY POINTS: • CTP imaging of the lower limb in patients with symptomatic PAD seems feasible for assessing hemodynamic differences before and after revascularisation in PAD patients. • This quantitative method might serve as a non-invasive method, for surveillance and therapy control of patients with PAD.

Beyond Single-Cell Analysis of Metallodrugs by ICP-MS: Targeting Cellular Substructures.

Platinum compounds such as cisplatin (cisPt) embody the backbone of combination chemotherapy protocols against advanced lung cancer. However, their efficacy is primarily limited by inherent or acquired platinum resistance, the origin of which has not been fully elucidated yet, although of paramount interest. Using single cell inductively coupled plasma mass spectrometry (SC-ICP-MS), this study quantifies cisPt in single cancer cells and for the first time in isolated nuclei. A comparison of cisPt uptake was performed between a wild type (wt) cancer cell line and related resistant sublines. In both, resistant cells, wt cells, and their nuclei, cisPt uptake was measured at different incubation times. A lower amount of cisPt was found in resistant cell lines and their nuclei compared to wt cells. Moreover, the abundance of internalized cisPt decreased with increasing resistance. Interestingly, concentrations of cisPt found within the nuclei were higher than compared to cellular concentrations. Here, we show, that SC-ICP-MS allows precise and accurate quantification of metallodrugs in both single cells and cell organelles such as nuclei. These findings pave the way for future applications investigating the potency and efficacy of novel metallodrugs developed for cancer treatment.

Non-contrast-enhanced 3-Tesla Magnetic Resonance Imaging Using Surface-coil and Sonography for Assessment of Hidradenitis Suppurativa Lesions.

Hidradenitis suppurativa has a substantial negative effect on quality of life of affected persons. Diagnosis is based mainly on clinical examination. However, physi-cal examination alone might underestimate disease severity compared with imaging modalities. We report here the application of non-contrast-enhanced 3-Tesla magnetic resonance imaging using surface-coil and sonography for assessment of hidradenitis suppurativa lesions based on topographic assessment of skin lesions. In addition, we review the literature regarding the application of ultrasound and magnetic resonance imaging in hidradenitis suppurativa.

Comparison of PSMA-ligand PET/CT and multiparametric MRI for the detection of recurrent prostate cancer in the pelvis.

PURPOSE: So far, there have been very few studies which provide a direct comparison between MRI and PSMA-ligand PET/CT for the detection of recurrent prostate cancer (rPC). This present study therefore aims to provide further clinical data in order to resolve this urgent clinical question, and thereby strengthen clinical recommendations. METHODS: A retrospective analysis was performed for patients who were scanned at our institution with whole-body PSMA-PET/CT (tracer: 68Ga-PSMA-11) between January 2017 and September 2018 in order to detect rPC. Amongst them, 43 underwent an additional pelvic MRI within 2 months. Both modalities were compared as follows: a consensus read of the PET data was performed by two nuclear physicians. All lesions were recorded with respect to their type and localization. The same process was conducted by two radiologists for pelvic MRI. Thereafter, both modalities were directly compared for every patient and lesion. RESULTS: Overall, 30/43 patients (69.8%) presented with a pathologic MRI and 38/43 (88.4%) with a pathologic PSMA-PET/CT of the pelvis. MRI detected 53 pelvic rPC lesions (13 of them classified as "uncertain") and PSMA-PET/CT detected 75 pelvic lesions (three classified as "uncertain"). The superiority of PSMA-PET/CT was statistically significant only if uncertain lesions were classified as false-positive. CONCLUSIONS: PSMA-PET/CT detected more pelvic lesions characteristic for rPC when compared to MRI. In order to detect rPC, a potential future scenario could be conducting first a PSMA-PET/CT. Combining the advantages of both modalities in hybrid PET/MRI scanners would be an ideal future scenario.

Ex vivo performance comparison of three percutaneous biopsy needle systems.

PURPOSE: The aim of this study is to identify the micro-mechanical characteristics that define biopsy performance in normal ex vivo animal organs. MATERIALS AND METHODS: Three biopsy systems with differences of needle external diameter, tray height and effective tray length were assessed. Sampling was performed in porcine liver and kidneys with commercially labelled 14G, 16G and 18G, using 2-cm throw needle systems. Five samples were obtained per needle size and per organ, and the experiment was repeated twice for a total of 90 biopsy cores. Samples were analysed and compared in terms of macroscopic aspect, sample length, weight and tissue architecture. RESULTS: The system with the longest effective needle tray (system A) has shown significant superiority (p < 0.001) versus the other systems regarding the mean weight of tissue obtained for all needle sizes. Furthermore, the 14G needle of system A has shown superiority regarding the number of portal spaces and the 16G regarding the length of kidney fragments obtained. CONCLUSION: The outcomes obtained with the different biopsy systems were not equal. The micro-mechanical characteristic that appears to influence the quantity and quality of the obtained tissue is the effective needle tray length and not the needle external diameter or the needle tray height. This information should be taken into account in the future design of biopsy needle systems, particularly when potentially used in the assessment of biomarkers and the characterisation of tumour micro-environment. KEY POINTS: • The amount of obtained tissue mass is not the same among percutaneous biopsy needle systems. • There are different micro-mechanical characteristics that condition the amount of obtained tissue. • The micro-mechanical characteristic that offers more tissue mass for the same calibre is the effective length of the needle tray.

Radiologists and nuclear medicine physicians are looking forward to a cross-curricular training.

OBJECTIVES: To obtain an overview of the attitudes toward interdisciplinary further education of residents and consultants in radiology and nuclear medicine and preferences regarding a future joint training curriculum in Switzerland. METHODS: A 34-item questionnaire was sent electronically (SurveyMonkey online survey tool) to 1244 radiologists and nuclear physicians (residents and consultants) in Switzerland. The items asked about the motivation for further education in each other's specialty and preferences regarding a joint further education curriculum in radiology and nuclear medicine. RESULTS: Overall, 370 questionnaires were analyzed (370/1244, 30%). There were 280 (76%) board-certified physicians in either radiology (238/370, 64%) or nuclear medicine (42/370, 12%) and 65 (18%) residents (radiology 54/370, 15%; nuclear medicine 11/370, 3%). More than half of all residents (34/65, 52%) stated their conviction that a wide range of expertise in both disciplines could be fully guaranteed through adequate cross-curricular training. For responders already at a consultant level in radiology or nuclear medicine, the willingness to undergo further training in each other's specialty significantly increased with a shorter training period. The preferred option for a possible future joint training curriculum was a combination of a 5-year radiology training program with 2 years of further training in nuclear medicine. CONCLUSIONS: Both residents and board-certified physicians in Switzerland are highly interested in a cross-curricular training curriculum in radiology and nuclear medicine. KEY POINTS: • A systematic survey was conducted to obtain information on interest in cross-curricular training in radiology and nuclear medicine and preferences regarding a future joint training curriculum. • More than half of radiology and nuclear medicine residents would be interested in further training in the other specialty. • There is a strong desire for a shorter training program when combining training in both radiology and nuclear medicine.

What you should know about prophylaxis and treatment of radiographic and magnetic resonance contrast medium extravasation.

In addition to anaphylactic reactions induced by contrast media (CM), extravasation is an adverse reaction that occurs immediately, requires special treatment, and attention. Since radiologists are often not familiar with either prophylactic or treatment modalities, the goal of this paper is to summarize the major facts and recommendations with respect to CM extravasation under practical clinical aspects.

In vitro T2 relaxivities of the Gd-based contrast agents (GBCAs) in human blood at 1.5 and 3 T.

BACKGROUND: The availability of data in the medical literature for the T2 relaxivities of the Gd-based contrast agents (GBCAs) is limited. A comprehensive comparison between the agents available commercially (other than in Europe) is lacking, with no data available that most closely reflect the clinic, which is in human whole blood at body temperature. PURPOSE: To complement the existing literature by determining T2 relaxivity data for eight GBCAs in vitro. MATERIAL AND METHODS: The relaxivities of eight GBCAs diluted in human whole blood at 1.5 and 3 T were determined at 37 ± 0.5 °C. Gd was in the range of 0-4 mM. Multi-echo sequences with variable echo times were acquired using a phantom containing a dilution series with each agent, and SigmaPlot 12.0 was used to calculate the R2 relaxation rate and finally r2. Statistical comparisons between agents and field strengths were conducted. RESULTS: The relationship between R2 vs. Gd was observed to be linear at 1.5 and 3 T, with a mild increase in r2 from 1.5 to 3 T for all GBCAs. T2 relaxivity data were compared with prior results. The GBCAs are closely clustered into two groups, with higher r2 noted for the two lipophilic (those with partial hepatobiliary excretion) compounds. CONCLUSION: The r2 values at 1.5 and 3 T, determined for the eight GBCAs still clinically available (other than in Europe), provide a definitive baseline for future evaluations, including theoretical calculations of signal intensity and their clinical impact on T2-weighted scans.

Improved identification of DNA double strand breaks: γ-H2AX-epitope visualization by confocal microscopy and 3D reconstructed images.

Currently, in the context of radiology, irradiation-induced and other genotoxic effects are determined by visualizing DSB-induced DNA repair through γ-H2AX immunofluorescence and direct counting of the foci by epifluorescence microscopy. This procedure, however, neglects the 3D nature of the nucleus. The aim of our study was to use confocal microscopy and 3D reconstructed images to improve documentation and analysis of γ-H2AX fluorescence signals after diagnostic examinations. Confluent, non-dividing MRC-5 lung fibroblasts were irradiated in vitro with a Cs-137 source and exposed to radiation doses up to 1000 mGy before fixation and staining with an antibody recognizing the phosphorylated histone variant γ-H2AX. The 3D distribution of γ-H2AX foci was visualized using confocal laser scanning microscopy. 3D reconstruction of the optical slices and γ-H2AX foci counting were performed using Imaris Image Analysis software. In parallel, γ-H2AX foci were counted visually by epifluorescence microscopy. In addition, whole blood was exposed ex vivo to the radiation doses from 200 to 1600 mGy. White blood cells (WBCs) were isolated and stained for γ-H2AX. In fibroblasts, epifluorescence microscopy alone visualized the entirety of fluorescence signals as integral, without correct demarcation of single foci, and at 1000 mGy yielded on average 11.1 foci by manual counting of 2D images in comparison to 36.1 foci with confocal microscopy and 3D reconstruction (p < 0.001). The procedure can also be applied for studies on WBCs. In contrast to epifluorescence microscopy, confocal microscopy and 3D reconstruction enables an improved identification of DSB-induced γ-H2AX foci, allowing for an unbiased, ameliorated quantification.

Subspecialization in radiology: effects on the diagnostic spectrum of radiologists and report turnaround time in a Swiss university hospital.

PURPOSE: To analyze the changes in the work profiles of radiologists and the reporting time after the implementation of professional subspecialization in the radiology department of a Swiss university hospital. METHODS: In a retrospective analysis, the overall number of different radiologic examinations performed in the department of radiology of the largest Swiss university hospital was documented for 2014 and 2016 before and after the implementation of subspecialized reporting (subspecialities: abdominal, musculoskeletal, cardiothoracic, emergency, and pediatric imaging) in May 2015. For six selected radiologists, the number and types of reported examinations as well as the related radiology report turnaround times (RTATs) were analyzed in detail and compared between the two 1-year periods. RESULTS: Overall, there was a significant increase of 10.3% in the total number of examinations performed in the whole department in 2016 compared with 2014. For four of the six radiologists, the range of different types of examinations significantly decreased with the introduction of subspecialized reporting (p < 0.05). Furthermore, there was a significant change in the subset of the ten most commonly reported types of examinations reported by each of the six radiologists. Mean overall RTATs significantly increased for five of the six radiologists (p < 0.05). CONCLUSIONS: Implementation of subspecialized reporting led to a change in the structure and a decrease in the range of different examination types reported by each radiologist. Mean RTAT increased for most radiologists. Subspecialized reporting allows the individual radiologist to focus on a special field of professional competence but can result in longer overall RTAT.