Weikert T, et al. Korean J Radiol. 2021 Jan;22:e24. https://doi.org/10.3348/kjr.2020.0994

Background: Presence of right ventricular thrombus (RVT) is a rare but life-threatening condition, thus immediate diagnosis and therapy are mandatory. Unfortunately, detection and distinction from intraventricular tumour masses or vegetations represent a complex task. Furthermore, consecutive therapy is principally led by clinical presentation without considering morphological features of the thrombus. Current literature suggests a multimodal non-invasive imaging approach. In this article, we discuss the role of cardiac magnetic resonance imaging (CMR) for the detection of RVT in patients with pulmonary embolism (PE). We consider the relatively expensive and not broadly available imaging procedure and weigh it up to its assumed high sensitivity, specificity, and importance for differential diagnosis and therapeutic decision-making. Case summary: In this case series, we report three cases of RVT with concomitant PE, whereof two were missed during routine cardiac workup by transthoracic echocardiography and computer tomography. Cardiac magnetic resonance imaging led to detection and further characterization of the thrombi in both cases. Conclusions: Cardiac magnetic resonance imaging reliably detects and characterizes RVT, even under unfavourable conditions for echocardiography such as arrhythmia, adiposity, or in posterior position of RVT. Obtained information could facilitate the choice of therapeutic approach (anticoagulation vs. systemic lysis vs. surgical thrombectomy). Future risk stratification scores will promote cost-effective use of CMR.

Follow-up is essential for the early detection of recurrent non-muscle invasive bladder cancers (NMIBC). This study investigates the clinical relevance of new diagnostic tools such as an mRNA-based urine test (XPERT© Bladder Cancer Monitor, XBCM) and Narrow Band Imaging© (NBI) and compares them with the established follow-up diagnostics (white-light cystoscopy (WLC) and urine cytology). This was a prospective, double-blind, single-center study that involved patients undergoing NMIBC screening at a tertiary care center. Enrollment occurred between January 2018 and March 2020. In addition to standard care (WLC, cytology, and ultrasound), patients underwent XBCM urine testing and NBI cystoscopy. In total, 301 WLCs were performed; through this, 49 patients demonstrated NMIBC recurrence. NBI cystoscopy was congruent with WLC in all patients. Cytology showed a sensitivity (SE) and specificity (SP) of 27% and 97% (PPV: 65%; NPV 87%), respectively, whereas XBCM showed SE and SP of 58% and 89%, respectively (PPV: 51%; NPV: 92%; AUC: 0.79 (0.716–0.871)). Subgroup analysis showed improved SE and similar SP (PPV, NPV) for high grade (HG) recurrence, with a SE of 74% and SP of 89% (39%, 97%). NBI cystoscopy does not necessarily provide additional benefit over standard WLC. However, the XBCM may provide better SE and a diagnostic advantage in instances of HG disease recurrence.

Background/Aim: Multiparametric dual energy comptuted tomography (CT) imaging allows for multidimensional tissue characterization beyond the measurement of Hounsfield units. The purpose of this study was to evaluate multiple imaging parameters for different abdominal organs in dual energy CT (DECT) and analyze the effects of the contrast agent on these different parameters and provide normal values for characterization of parenchymatous organs. Patients and Methods: This retrospective analysis included a total of 484 standardized DECT scans of the abdomen. Hounsfield Units (HU), rho (electron density relative to water), Z_eff (effective atomic number) and FF (fat fraction) were evaluated for liver, spleen, kidney, muscle, fat-tissue. Independent generalized estimation equation models were fitted. Results: In DECT imaging there is only little difference in mean HU_mixed for parenchymatous abdominal organs. Analysis including Z_eff, rho and FF allows for better discrimination while a large overlap remains for liver, spleen and muscle. Including multidimensional analysis and the effects of contrast medium further enhances tissue characterization. Small differences remain for liver and spleen. Conclusion: Organ characterization using multiparametric dual energy CT analysis is possible. An increased number of parameters obtained from DECT improves organ characterization. To our knowledge this is the first attempt to provide normal values for characterization of parenchymatous organs.

Objectives: Our study comprised a single-center retrospective in vitro correlation between spectral properties, namely ρ/Z values, derived from scanning blood samples using dual-energy computed tomography (DECT) with the corresponding laboratory hemoglobin/hematocrit (Hb/Hct) levels and assessed the potential in anemia-detection. Methods: DECT of 813 patient blood samples from 465 women and 348 men was conducted using a standardized scan protocol. Electron density relative to water (ρ or rho), effective atomic number (Z_eff), and CT attenuation (Hounsfield unit) were measured. Results: Positive correlation with the Hb/Hct was shown for ρ (r-values 0.37–0.49) and attenuation (r-values 0.59–0.83) while no correlation was observed for Z_eff (r-values −0.04 to 0.08). Significant differences in attenuation and ρ values were detected for blood samples with and without anemia in both genders (p value < 0.001) with area under the curve ranging from 0.7 to 0.95. Depending on the respective CT parameters, various cutoff values for CT-based anemia detection could be determined. Conclusion: In summary, our study investigated the correlation between DECT measurements and Hb/Hct levels, emphasizing novel aspects of ρ and Z_eff values. Assuming that quantitative changes in the number of hemoglobin proteins might alter the mean Z_eff values, the results of our study show that there is no measurable correlation on the atomic level using DECT. We established a positive in vitro correlation between Hb/Hct values and ρ. Nevertheless, attenuation emerged as the most strongly correlated parameter with identifiable cutoff values, highlighting its preference for CT-based anemia detection. Clinical relevance statement: By scanning multiple blood samples with dual-energy CT scans and comparing the measurements with standard laboratory blood tests, we were able to underscore the potential of CT-based anemia detection and its advantages in clinical practice. Key Points: Prior in vivo studies have found a correlation between aortic blood pool and measured hemoglobin and hematocrit. Hemoglobin and hematocrit correlated with electron density relative to water and attenuation but not Z_eff. Dual-energy CT has the potential for additional clinical benefits, such as CT-based anemia detection. Graphical