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Purpose: AI-assisted techniques for lesion registration and segmentation have the potential to make CT-based tumor follow-up assessment faster and less reader-dependent. However, empirical evidence on the advantages of AI-assisted volumetric segmentation for lymph node and soft tissue metastases in follow-up CT scans is lacking. The aim of this study was to assess the efficiency, quality, and inter-reader variability of an AI-assisted workflow for volumetric segmentation of lymph node and soft tissue metastases in follow-up CT scans. Three hypotheses were tested: (H1) Assessment time for follow-up lesion segmentation is reduced using an AI-assisted workflow. (H2) The quality of the AI-assisted segmentation is non-inferior to the quality of fully manual segmentation. (H3) The inter-reader variability of the resulting segmentations is reduced with AI assistance. Materials and methods: The study retrospectively analyzed 126 lymph nodes and 135 soft tissue metastases from 55 patients with stage IV melanoma. Three radiologists from two institutions performed both AI-assisted and manual segmentation, and the results were statistically analyzed and compared to a manual segmentation reference standard. Results: AI-assisted segmentation reduced user interaction time significantly by 33% (222 s vs. 336 s), achieved similar Dice scores (0.80–0.84 vs. 0.81–0.82) and decreased inter-reader variability (median Dice 0.85–1.0 vs. 0.80–0.82; ICC 0.84 vs. 0.80), compared to manual segmentation. Conclusion: The findings of this study support the use of AI-assisted registration and volumetric segmentation for lymph node and soft tissue metastases in follow-up CT scans. The AI-assisted workflow achieved significant time savings, similar segmentation quality, and reduced inter-reader variability compared to manual segmentation.

Diagnosing myocarditis relies on multimodal data, including cardiovascular magnetic resonance (CMR), clinical symptoms, and blood values. The correct interpretation and integration of CMR findings require radiological expertise and knowledge. We aimed to investigate the performance of Generative Pre-trained Transformer 4 (GPT-4), a large language model, for report-based medical decision-making in the context of cardiac MRI for suspected myocarditis.

There was no difference in diagnostic accuracy for detecting hemodynamically relevant coronary stenosis with CT myocardial perfusion versus CT-derived fractional flow reserve.

Skeletal muscle mass is subjected to constant changes and is considered a good predictor for outcome in various diseases. Bioelectrical‐impedance analysis (BIA) and magnetic resonance imaging (MRI) are approved methodologies for its assessment. However, muscle mass estimations by BIA may be influenced by excess intramuscular lipids and adipose tissue in obesity. The objective of this study was to evaluate the feasibility of quantitative assessment of skeletal muscle mass by MRI as compared with BIA. Subjects from a population‐based cohort underwent BIA (50 kHz, 0.8 mA) and whole‐body MRI including chemical‐shift encoded MRI (six echo times). Abdominal muscle mass by MRI was quantified as total and fat‐free cross‐sectional area by a standardized manual segmentation‐algorithm and normalized to subjects' body height2(abdominal muscle mass indices: AMMIMRI). Among 335 included subjects (56.3 ± 9.1 years, 56.1% male), 95 (28.4%) were obese (BMI ≥ 30 kg/m2). MRI‐based and BIA‐based measures of muscle mass were strongly correlated, particularly in non‐obese subjects [r< 0.74 in non‐obese (P< 0.001) vs. r< 0.56 in obese (P< 0.001)]. Median AMMITotal(MRI)was significantly higher in obese as compared with non‐obese subjects (3246.7 ± 606.1 mm2/m2vs. 2839.0 ± 535.8 mm2/m2, P< 0.001, respectively), whereas the ratio AMMIFat‐free/AMMITotal(by MRI) was significantly higher in non‐obese individuals (59.3 ± 10.1% vs. 53.5 ± 10.6%, P< 0.001, respectively). No significant difference was found regarding AMMIFat‐free(MRI)(P= 0.424). In analyses adjusted for age and sex, impaired glucose tolerance and measures of obesity were significantly and positively associated with AMMITotal(MRI)and significantly and inversely with the ratio AMMIFat‐free(MRI)/AMMITotal(MRI)(P< 0.001). MRI‐based assessment of muscle mass is feasible in population‐based imaging and strongly correlated with BIA. However, the observed weaker correlation in obese subjects may explain the known limitation of BIA in obesity and promote MRI‐based assessments. Thus, skeletal muscle mass parameters by MRI may serve as practical imaging biomarkers independent of subjects' body weight.

In the face of evolving medical knowledge, technologic innovation, and workforce shortages, radiology trainees face complex decisions on whether to pursue subspecialty training.

Hintergrund: Die Myokarditis und die inflammatorische Kardiomyopathie sind aufgrund ihrer unterschiedlichen Auslöser, Phänotypen und Stadien diagnostisch häufig schwer zu diagnostizieren. Methodische Innovationen und Probleme: Die kardiale Positronen-Emissions-Tomographie/Magnetresonanztomographie (PET/MRT) zeichnet sich neben der myokardialen Gewebecharakterisierung mittels MRT durch den möglichen Nachweis einer aktiven myokardialen Entzündung (Inflammation) mittels PET aus. Die Kombination von MRT und PET ist somit eher synergistisch als rein summativ: Die möglicherweise in der MRT vorhandenen kardialen Veränderungen lassen sich durch die PET in aktive inflammatorische (und somit noch potenziell reversible) Prozesse oder ältere chronische (irreversible) Narben unterscheiden. Die kardiale Sarkoidose mit einem potenziellen Nebeneinander von aktiven und chronischen Veränderungen bietet sich an, um die Stärken einer hybriden PET/MRT zur Geltung bringen zu lassen. Wichtig für eine aussagekräftige kardiale PET ist eine gute Vorbereitung mit Low-Carb-Diät, um eine suffiziente Suppression der myokardialen Glukoseaufnahme zu gewährleisten. Empfehlungen: Die Diagnostik einer inflammatorischen Herzerkrankung sowie deren Charakterisierung in akut vs. chronische Prozesse gelingt mit der kardialen Hybrid-PET/MRT, wie am Beispiel der kardialen Sarkoidose gezeigt werden konnte.

Cardiac imaging has a pivotal role in the prevention, diagnosis and treatment of ischaemic heart disease. SPECT is most commonly used for clinical myocardial perfusion imaging, whereas PET is the clinical reference standard for the quantification of myocardial perfusion. MRI does not involve exposure to ionizing radiation, similar to echocardiography, which can be performed at the bedside. CT perfusion imaging is not frequently used but CT offers coronary angiography data, and invasive catheter-based methods can measure coronary flow and pressure. Technical improvements to the quantification of pathophysiological parameters of myocardial ischaemia can be achieved. Clinical consensus recommendations on the appropriateness of each technique were derived following a European quantitative cardiac imaging meeting and using a real-time Delphi process. SPECT using new detectors allows the quantification of myocardial blood flow and is now also suited to patients with a high BMI. PET is well suited to patients with multivessel disease to confirm or exclude balanced ischaemia. MRI allows the evaluation of patients with complex disease who would benefit from imaging of function and fibrosis in addition to perfusion. Echocardiography remains the preferred technique for assessing ischaemia in bedside situations, whereas CT has the greatest value for combined quantification of stenosis and characterization of atherosclerosis in relation to myocardial ischaemia. In patients with a high probability of needing invasive treatment, invasive coronary flow and pressure measurement is well suited to guide treatment decisions. In this Consensus Statement, we summarize the strengths and weaknesses as well as the future technological potential of each imaging modality.

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Background: The use of multiparametric magnetic resonance imaging (mpMRI) in the setting of patients under active surveillance (AS) is promising. In this systematic-review we aimed to analyse the role of mpMRI in patients under AS. Methods: A comprehensive literature research for English-language original and review articles, recently published, was carried out using Medline, Scopus and Web of sciences databases until 30 October 2017. The following MeSH terms were used: 'active surveillance', 'prostate cancer', 'multiparametric magnetic resonance imaging'. A diagnostic meta-analysis was performed for 3.0 T mpMRI in predicting disease re-classification. Results: In total, 226 studies were selected after research and after removal of duplicates. After analysis on inclusion criteria, 43 studies were identified as eligible for this systematic review with a total of 6,605 patients. The timing of MRI during follow-up of AS differed from all studies like criteria for inclusion in the AS protocol. Overall, there was a low risk of bias across all studies. The diagnostic meta-analysis for 1.5 tesla showed a sensitivity of 0.60, negative predictive value (NPV) of 0.75 and a hierarchical summary receiving operating curve (HSROC) of 0.74 while for 3.0 tesla mpMRI a sensitivity of 0.81, a NPV of 0.78 and a HSROC of 0.83. Conclusions: Overall, the available evidence suggests that both 1.5 or 3.0 Tesla mpMRI are a valid tool to monitor progression during AS follow-up, showing good accuracy capabilities in detecting PCa re-classification. However, the modality to better define what means 'disease progression' on mpMRI must be further evaluated.

To evaluate the benefits of arterial phase imaging and parenchymal blood volume (PBV) maps acquired by C-arm computed tomography during TACE procedure in comparison to cross-sectional imaging (CSI) using CT or MRI. From January 2014 to December 2016, a total of 29 patients with HCC stage A or B (mean age 65 years; range 47 to 81 years, 86% male) were included in this study. These patients were referred to our department for TACE treatment and received peri-interventional C-arm CT. Dual phase findings of each lesion in terms of overall image quality, conspicuity, tumor size and feeding arteries were compared between arterial phase imaging and PBV using 5-point semi-quantitative Likert-scale, whereby pre-interventional CSI served as reference standard. A significantly higher overall image quality of the PBV maps compared to arterial phase C-arm CT acquisitions (4.34 (±0.55) vs. 3.93 (±0.59), p= 0.0032) as well as a higher conspicuity of HCC lesions (4.27 ± 0.74 vs. 3.83 ± 1.08, p< 0.0001) was observed. Arterial phase imaging led to an overestimation of tumor size (mean size, 26.5 ± 15.9 mm) compared to PBV (24.9 ± 15.2 mm, p= 0.0004) as well as CSI (25.2 ± 15.1 mm), p= 0.021). Regarding detectability of tumor feeding arterial vessels, significantly more feeding vessels were detected in arterial phase C-arm CT (n= 1.67 ± 0.92 vessels) compared to PBV maps (n= 1.27 ± 0.63 vessels) (p= 0.0001). One lesion was missed in pre-interventional CT imaging, but detected by C-arm CT. The combination of PBV maps and arterial phase images acquired by C-arm CT during TACE procedure enables precise detection of the majority of HCC lesions and tumor feeding arteries and has therefore the potential to improve patient outcome.

In medical imaging, the digital post-processing and analysis of acquired images has become an important research field. Topics include various applications of image processing and machine learning aiming to assist radiologists in their diagnostic work. A crucial step in successfully implementing such systems is finding appropriate mathematical descriptions to reflect characteristics of acquired images. Which features are the most meaningful ones strongly depends on the underlying scientific/diagnostic question and the image itself. This makes researching, implementing and testing features time-consuming and cost-intensive. In our work, we aim to address this issue by creating ImFEATbox, a publicly available toolbox to extract and analyze image features for a wide range of applications. To reduce the amount of time spent for choosing the right features, we provide an assortment of feature extraction algorithms which are suitable for a broad variety of medical image processing problems. The toolbox includes both global and local features as well as feature descriptors. While being primarily developed in MATLAB, the majority of our algorithms is also available in Python to enable access to a wider range of researchers. We tested the applicability of ImFEATbox on an FDG-PET/CT data set of 12 patients diagnosed with lung cancer and an MRI data set of 50 patients with prostate lesions. Employing the implemented algorithms in an exemplary manner, we are able to demonstrate its potential for different scientific problems, e.g., show differences between features, indicate redundancies in extracted feature sets by means of a correlation analysis and training a SVM to distinguish between high-risk and low-risk prostate lesions. ImFEATbox provides a variety of feature extraction algorithms suitable for a large number of post-processing and analysis applications in medical imaging. The toolbox is publicly available and can thus be beneficial to a wide range of researchers working on medical image analysis.

To investigate the added diagnostic value of diffusion-weighted imaging (DWI) of the liver and its impact on therapy decisions in patients with hepatic malignancy. Interdisciplinary gastrointestinal tumorboard cases concerning patients with hepatic malignancies discussed between 11/2015 and 06/2016 were included in this retrospective, single-center study. Two radiologists independently reviewed the respective liver MR-examination first without, then with DWI. The readers were blinded regarding number, position and size of hepatic malignancies. Cases in which DWI revealed additional findings concerning the hepatic tumor status as compared to conventional sequences alone were presented to experienced members of the interdisciplinary tumor board. In this retrospective setting changes in treatment decisions based on these additional findings in the DWI sequences were recorded. A total of 87 patients were included. DWI revealed additional findings in 12 patients (13,8%). These new findings had a direct effect on the therapy in 8 patients (9,2%): In 6 patients (6,9%) the surgical/interventional treatment was adapted (n= 5: extended resection, n= 1: with transarterial chemoembolization of a single hepatocellular carcinoma only detectable in DWI); 2 patients (2,3%) received systemic therapy (n = 1: neo-adjuvant, n = 1: palliative) based on the additional findings in DWI. In 4 patients (4.6%) additional DWI findings did not affect the therapeutic decision. DWI is a relevant diagnostic tool in oncologic imaging of the liver. By providing further information regarding tumor load in hepatic malignancies it can lead to a significant change in treatment.

Aim To evaluate voxelwise computed diffusion-weighted imaging (vcDWI) for the detection of cytotoxic oedema in brain imaging and to quantify the benefit of lesion contrast in comparison to standard b = 1000 s/mm2by the example of acute ischaemic stroke.Materials and methods A retrospective evaluation of 66 patients (63 ± 15.9 years) suspected for acute ischaemic stroke who received diffusion-weighted magnetic resonance imaging and fluid-attenuated inversion recovery sequence. A neuroradiologist evaluated all examinations for acute ischaemic stroke based on diffusion-weighted imaging, the apparent diffusion coefficient and fluid-attenuated inversion recovery (reference standard) and 6 weeks later the vcDWI in a randomised manner. Time of analysis was noted. Signal intensities were acquired in lesions, in healthy tissue as well as in the cerebrospinal fluid. Contrast ratios and coefficients of variation were computed.Results A total of 218 lesions was found in 46/66 patients. vcDWI identified all patients and lesions correctly. The median evaluation time was 36 seconds (4–126 s) for the vcDWI and 44 seconds (9–186 s; P< 0.001) for the diffusion-weighted imaging/apparent diffusion coefficient reading. The contrast ratio in vcDWI (mean value 2.57, range 1.73–4.11) was higher than in b= 1000 s/mm2(2.33, 0.83–3.85, P= 0.03) and the apparent diffusion coefficient map (1.83, 1.00–3.00, P< 0.001), respectively. Coefficients of variation in lesions and tissue did not differ significantly between vcDWI and b= 1000 s/mm2(P= 0.81/P= 0.26). The signal intensity of cerebrospinal fluid was lower in vcDWI than in b= 1000 mm2/s (0.08 and 34.8, P< 0.001).Conclusion It could be shown that vcDWI has the potential to accelerate the detection of diffusion-restricted lesions in neuroimaging by improving the contrast ratios and reducing the T2 shine-through effect in comparison to standard diffusion-weighted imaging in brain imaging.

To assess the diagnostic utility of different perfusion algorithms for the detection of angiographical terial spasm.

Multiparametric magnetic resonance imaging (mpMRI) is gaining acceptance to guide targeted biopsy (TB) in prostate cancer (PC) diagnosis. We aimed to compare the detection rate of software-assisted fusion TB (SA-TB) versus cognitive fusion TB (COG-TB) for PC and to evaluate potential clinical features in detecting PC and clinically significant PC (csPC) at TB.

Our study demonstrated a significant reduction in diagnostic accuracy for renal lesion characterization caused by significantly higher miss rates for minimally enhancing solid renal tumors at virtual monoenergetic imaging energies greater than 70 keV (P≤ .0039).

Radiation dose reduction to 40% of original dose levels may be performed in perfusion CT imaging of patients with aneurysmal subarachnoid hemorrhage without compromising the diagnostic accuracy regarding detection of cerebral perfusion impairment.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jtcvs.2009.05.019 Byline: Michael Schmoeckel (a), Peter Boekstegers (b), Konstantin Nikolaou (c), Bruno Reichart (a) Author Affiliation: (a) Department of Cardiac Surgery, Klinikum Grosshadern, Ludwig-Maximilians-University, Munich, Germany (b) Department of Internal Medicine I, Klinikum Grosshadern, Ludwig-Maximilians-University, Munich, Germany (c) Department of Radiology, Klinikum Grosshadern, Ludwig-Maximilians-University, Munich, Germany Article History: Received 4 May 2009; Accepted 17 May 2009

Aim of the study was to evaluate the influence of the selection of measured b-values on the precision of cDWI in the upper abdomen as well as on the lesion contrast of PET-positive liver metastases in cDWI and vcDWI.

Due to prolonged survival and technical advances in CT imaging, cardiac metastases in patients with malignant melanoma are observed more frequently nowadays. The aim of the present study was to assess the anatomic distribution as well as the morphologic and histologic appearance of cardiac metastases from malignant melanoma. Twenty five patients with known metastasized melanoma and with incidental finding of cardiac metastases during routine staging CT were retrospectively included in this study. CT images were assessed for the presence, localization and extent of cardiac metastases. Histological results, mutational analysis and tumor markers were reviewed. Fourteen out of 25 patients presented with singular cardiac mass (56%), whereas ten patients (40%) presented with multifocal and one patient with disseminated cardiac metastases. Twelve patients presented with endocardial (48%), eight with myocardial and two with pericardial metastases. Most frequent site involved in endocardial metastases was the right atrium (67%) followed by the right ventricle (33%). There seems to be a correlation between histological subtype and location of cardiac metastasis. Median survival after diagnosis of cardiac metastases was 8 months, with no significant difference regarding the localization of metastases within the heart. Cardiac metastases can involve every part of the heart possibly in dependence of histological subtype. The awareness of different types of cardiac metastases and their characteristic appearance on CT images is necessary for further investigations and might contribute to targeted therapy.

MRI and perfusion-CT (PCT) are both useful imaging techniques for detection and characterization of liver lesions. The aim of this study was to compare the diagnostic accuracy of imaging parameters derived from PCT and gadoxetic acid-enhanced MRI in patients with hepatocellular carcinoma (HCC). 36 patients with liver cirrhosis and a total of 67 lesions referred to our hospital for multi-parametric diagnosis of HCC-suspected liver lesions in the setting of liver cirrhosis were prospectively enrolled and underwent PCT and MRI. HCC diagnosis was confirmed either by histology (n= 60) or interval growth (n= 7). For PCT, mean/max blood flow (BF), blood volume (BV), k-trans, arterial liver perfusion (ALP), portal venous perfusion (PVP) and hepatic perfusion index (HPI) were quantified. Two readers identified the lesions based on single maps each being blinded to the number of lesions. MRI-protocol included fat-suppressed T1w-VIBE sequences obtained before, 2, 5, 10 and 20 min after the injection of gadoxetic acid as well as non-enhanced coronal HASTE, axial T1w-VIBE, fat-suppressed T2w-TSE and DWI. Quantitative analysis was performed using enhancement ratios between tumor and liver parenchyma for post-contrast in the hepatobiliary phase (RIRHB), arterial (ERa) and late-venous (ERv) phases as well as signal intensity ratios (liver/parenchyma) on T1w (RIRT1) and T2w (RIRT2). In PCT analysis, all lesions exhibited high BFmaxvalues (63–250 mL/100 g tissue) and were visible on HPI maps with high degrees of arterial blood supply of (HPI > 96%). In MRI, RIRHBwas negative in 8/67. 12/67 HCCs were missed on DWI. 46/67 HCCs showed wash-in and 47/67 HCC showed wash-out of contrast agent. 6/67 HCCs were missed on T1w and 11/67 were missed on T2w-sequences when analyzed separately, while analysis of multiparametric MRI combining typical enhancement pattern, visibility on hepatobiliary phase and T1w-images the same number of lesions as PCT irrespective of their size (1–19 cm) were detected. Quantification of early enhancement by ERaor ERvdid not improve detection rates. Perfusion-CT and gadoxetic acid-enhanced MRI were comparable in detecting HCC lesions. For PCT a mean HPI > 96% proved to be a very robust parameter for detection and characterization of HCC.

In patients with suspected pulmonary embolism, free-breathing pseudo-continuous arterial spin labeling MRI had high diagnostic accuracy and interchangeable results with CT pulmonary angiography.

Cholangiocarcinoma (CC) is the second most common primary hepatobiliary tumour, and it is increasing in incidence. Imaging characteristics, behaviour, and therapeutic strategies in CC differ significantly, depending on the morphology and location of the tumour. In cross-sectional imaging, CCs can be classified according to the growth pattern (mass-forming, periductal infiltrating, intraductal) and the location (intrahepatic, perihilar, extrahepatic/distal). The prognosis of CC is unfavourable and surgical resection is the only curative treatment option; thus, early diagnosis (also in recurrent disease) and accurate staging including the evaluation of lymph node involvement and vascular infiltration is crucial. However, the diagnostic evaluation of CC is challenging due to the heterogeneous nature of the tumour. Diagnostic modalities used in the imaging of CC include transabdominal ultrasound, endosonography, computed tomography, magnetic resonance imaging with cholangiopancreatography, and hybrid imaging such as positron emission tomography/computed tomography. In this review, the potential of cross-sectional imaging modalities in primary staging, treatment monitoring, and detection of recurrent disease will be discussed.

To evaluate the interchangeability of perfusion parameters obtained with help of models used for post-processing of perfusion-CT images in pancreatic adenocarcinoma and to determine the mean values and ranges of perfusion in different tumour gradings. Perfusion-CT imaging was performed prospectively in 48 consecutive patients with pancreatic adenocarcinoma. In 42 patients biopsy-proven tumor grading was available (4 × G1/24 × G2/14 × G3/6× unknown). Images were post-processed using a model based on the maximum-slope (MS) approach (blood flow-BFMS) + Patlak analysis (P) (blood volume [BVP] and permeability [k-transP]), as well as a model with deconvolution-based (D) analysis (BFD, BVD and k-transD). 50 mL contrast agent were applied with a delay time of 7 s. Perfusion parameters were compared using intraclass correlation coefficient (ICC), the Wilcoxon matched-pairs test and Bland-Altman plots. Forty eight VOIs of tumours were outlined and analysed. Moderate to good ICC values were found for the perfusion parameters (ICC = 0.62–0.75). Wilcoxon matched-pairs revealed significantly lower values (P< .001 and 0.008), for the BF and BV values obtained using the maximum-slope approach + Patlak analysis compared to deconvolution based analysis. For k-trans measurement, deconvolution revealed significantly lower values (P< 0.001). Different histologic subgroups (G1-G3) did not show significantly different functional parameters. There were significant differences in the perfusion parameters obtained using the different calculation methods, and therefore these parameters are not directly interchangeable. However, the magnitude of pairs of parametric values is in constant relation to each other enabling the use of any of these methods. VPCT parameters did not allow for histologic classification.

This study aims to evaluate immediate changes in perfusion parameters in hepatocellular carcinoma (HCC) to transarterial chemoembolization (TACE) in C-arm computed tomography (CT) and volume perfusion CT (VPCT) and prediction of midterm tumor response. Twenty-five patients (median age 66, range 61 to 75 years) with 62 HCC lesions undergoing TACE received immediate pre- and post-interventional assessment by C-arm CT and VPCT. Cross-sectional imaging was analyzed at baseline and approximately 12 weeks after TACE according to modified RECIST criteria. Outcome was defined as objective response (OR, > 30 % reduction of viable tumor) or non-OR. Perfusion parameters were evaluated in C-arm CT [parenchymal blood volume (PBV)] and VPCT [blood volume (BV) and blood flow (BF)]. Ratios of perfusion parameters before and after TACE within the tumor and the non-affected liver parenchyma were calculated. Correlation between tumor PBV and BV revealed a moderate correlation (rho = 0.45, p= 0.005). In non-affected liver parenchyma, a significant decrease in PBV was seen, compared to a significant increase in BF and BV. Perfusion ratios in HCC lesions were significantly (p< 0.05) increased in OR group compared to non-OR patients in C-arm CT and VPCT: PBV ratio (0.95 (0.06) to 0.67 (0.38), BV ratio 0.63 (0.34) to 0.15 (0.6), and BF ratio 0.6 (0.32) to 0.22 (0.51). Logistic regression including PBV and BF allowed prediction of OR (sensitivity 88 %/specificity of 83 %). Perfusion parameters acquired by C-arm CT and VPCT cannot simply be substituted by each other, but show similar capability in prediction of midterm tumor response.

Supplemental digital content is available in the text.

Supplemental digital content is available in the text.

En los últimos años, la coronariografía (o angiografía coronaria) por tomografía computarizada se ha asentado cada vez más como una modalidad diagnóstica segura y no invasiva para la evaluación de la antomía del árbol arterial coronario, que aporta ventajas diagnósticas, en especial para pacientes con probabilidad pretest baja o intermedia de la enfermedad. Actualmente hay cada vez más evidencia de grandes ensayos aleatorizados sobre la influencia diagnóstica de la angiotomografía computarizada en el manejo de los pacientes con síndromes de dolor torácico agudo y crónico. Al mismo tiempo, los avances técnicos han reducido sustancialmente los efectos adversos y los factores limitantes, como la exposición a la radiación, la cantidad de medio de contraste yodado que se aplica y el tiempo de exploración, lo cual la hace apropiada para aplicaciones clínicas más amplias. En este trabajo se revisan los avances más recientes en la tecnología de la tomografía computarizada y se describe la evidencia científica existente sobre el uso de la angiotomografía computarizada cardiaca en la evaluación de los pacientes con síndromes de dolor torácico agudo y crónico.

Perfusion CT (PCT) of the brain is widely used in the settings of acute ischemic stroke and vasospasm monitoring. The high radiation dose associated with PCT is a central topic and has been a focus of interest for many researchers. Many studies have examined the effect of radiation dose reduction in PCT using different approaches. Reduction of tube current and tube voltage can be efficient and lead to a remarkable reduction of effective radiation dose while preserving acceptable image quality. The use of novel noise reduction techniques such as iterative reconstruction or spatiotemporal smoothing can produce sufficient image quality from low-dose perfusion protocols. Reduction of sampling frequency of perfusion images has only little potential to reduce radiation dose. In the present article we aimed to summarize the available data on radiation dose reduction in PCT imaging of the brain.

Nuclear medicine plays a valuable role in the evaluation of cardiovascular diseases, allowing noninvasive evaluation of cardiac physiology and function that provides complementary information to anatomic techniques.©RSNA, 2022