Pre-existing Interstitial Lung Abnormalities and Immune Checkpoint Inhibitor-Related Pneumonitis in Solid Tumors: A Retrospective Analysis.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have demonstrated efficacy over previous cytotoxic chemotherapies in clinical trials among various tumors. Despite their favorable outcomes, they are associated with a unique set of toxicities termed as immune-related adverse events (irAEs). Among the toxicities, ICI-related pneumonitis has poor outcomes with little understanding of its risk factors. This retrospective study aimed to investigate whether pre-existing interstitial lung abnormality (ILA) is a potential risk factor for ICI-related pneumonitis. MATERIALS AND METHODS: Patients with non-small cell lung cancer, malignant melanoma, renal cell carcinoma, and gastric cancer, who was administered either nivolumab, pembrolizumab, or atezolizumab between September 2014 and January 2019 were retrospectively reviewed. Information on baseline characteristics, computed tomography findings before administration of ICIs, clinical outcomes, and irAEs were collected from their medical records. Pre-existing ILA was categorized based on previous studies. RESULTS: Two-hundred-nine patients with a median age of 68 years were included and 23 (11.0%) developed ICI-related pneumonitis. While smoking history and ICI agents were associated with ICI-related pneumonitis (P = .005 and .044, respectively), the categories of ILA were not associated with ICI-related pneumonitis (P = .428). None of the features of lung abnormalities were also associated with ICI-related pneumonitis. Multivariate logistic analysis indicated that smoking history was the only significant predictor of ICI-related pneumonitis (P = .028). CONCLUSION: This retrospective study did not demonstrate statistically significant association between pre-existing ILA and ICI-related pneumonitis, nor an association between radiologic features of ILA and ICI-related pneumonitis. Smoking history was independently associated with ICI-related pneumonitis. Further research is warranted for further understanding of the risk factors of ICI-related pneumonitis.

Prediction of pathological up-staging after radical nephroureterectomy in patients with upper tract urothelial carcinoma.

PURPOSE: The diagnostic accuracy of computed tomography urography for upper tract urothelial carcinoma is high; however, difficulties are associated with precisely assessing the T stage. Preoperative tumor staging has an impact on treatment options for upper tract urothelial carcinoma. We herein attempted to identify preoperative factors that predict pathological tumor up-staging, which will facilitate the selection of treatment strategies. MATERIALS AND METHODS: We retrospectively identified 148 patients with upper tract urothelial carcinoma who underwent computed tomography urography preoperatively followed by radical nephroureterectomy without preoperative chemotherapy at our institution between 2000 and 2021. Preoperative factors associated with cT2 or lower to pT3 up-staging were examined using a multivariate logistic regression analysis. RESULTS: Ninety out of 148 patients were diagnosed with cT2 or lower, and 22 (24%) were up-staged to pT3. A multivariate analysis identified a positive voided urine cytology (HR 4.69, p = 0.023) and tumor length ≥ 3 cm (HR 6.33, p = 0.003) as independent predictors of pathological tumor up-staging. CONCLUSIONS: Patients diagnosed with cT2 or lower, but with preoperative positive voided urine cytology and/or tumor diameter ≥ 3 cm need to be considered for treatment as cT3.

RASopathies for Radiologists.

RASopathies are a heterogeneous group of genetic syndromes caused by germline mutations in a group of genes that encode components or regulators of the Ras/mitogen-activated protein kinase (MAPK) signaling pathway. RASopathies include neurofibromatosis type 1, Legius syndrome, Noonan syndrome, Costello syndrome, cardiofaciocutaneous syndrome, central conducting lymphatic anomaly, and capillary malformation-arteriovenous malformation syndrome. These disorders are grouped together as RASopathies based on our current understanding of the Ras/MAPK pathway. Abnormal activation of the Ras/MAPK pathway plays a major role in development of RASopathies. The individual disorders of RASopathies are rare, but collectively they are the most common genetic condition (one in 1000 newborns). Activation or dysregulation of the common Ras/MAPK pathway gives rise to overlapping clinical features of RASopathies, involving the cardiovascular, lymphatic, musculoskeletal, cutaneous, and central nervous systems. At the same time, there is much phenotypic variability in this group of disorders. Benign and malignant tumors are associated with certain disorders. Recently, many institutions have established multidisciplinary RASopathy clinics to address unique therapeutic challenges for patients with RASopathies. Medications developed for Ras/MAPK pathway-related cancer treatment may also control the clinical symptoms due to an abnormal Ras/MAPK pathway in RASopathies. Therefore, radiologists need to be aware of the concept of RASopathies to participate in multidisciplinary care. As with the clinical manifestations, imaging features of RASopathies are overlapping and at the same time diverse. As an introduction to the concept of RASopathies, the authors present major representative RASopathies, with emphasis on their imaging similarities and differences. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Exploration of postural effects on the external jugular and diploic venous system using upright computed tomography scanning.

PURPOSE: Few studies have investigated the influence of posture on the external jugular and diploic venous systems in the head and cranial region. In this study, we aimed to investigate the effects of posture on these systems using upright computed tomography (CT) scanning. METHODS: This study retrospectively analysed an upright CT dataset from a previous prospective study. In each patient, the diameters of the vessels in three external jugular tributaries and four diploic veins were measured using CT digital subtraction venography in both supine and sitting positions. RESULTS: Amongst the 20 cases in the original dataset, we eventually investigated 19 cases due to motion artifacts in 1 case. Compared with the supine position, most of the external jugular tributaries collapsed, and the average size significantly decreased in the sitting position (decreased by 22-49% on average). In contrast, most of the diploic veins, except the occipital diploic veins, tended to increase or remain unchanged (increased by 12-101% on average) in size in the sitting position compared with the supine position. However, the changes in the veins associated with this positional shift were not uniform; in approximately 5-30% of the cases, depending on each vein, an opposite trend was observed. CONCLUSION: Compared to the supine position, the contribution of external jugular tributaries to head venous drainage decreased in the sitting position, whilst most diploic veins maintained their contribution. These results could enhance our understanding of the physiology and pathophysiology of the head region in upright and sitting positions.

Assessment of Myocardial 18F-FDG Uptake at PET/CT in Asymptomatic SARS-CoV-2-vaccinated and Nonvaccinated Patients.

Background Patients who developed myocarditis following SARS-CoV-2 vaccination show abnormalities on cardiac MRI. However, whether myocardial changes occur in asymptomatic individuals following vaccination is not well established. Purpose To assess myocardial 18Fluorine-fluorodeoxyglucose (18F-FDG) uptake on PET/CT in asymptomatic SARS-CoV-2 vaccinated patients compared to nonvaccinated patients. Materials and Methods This retrospective study included patients who underwent 18F-FDG PET/CT for indications unrelated to myocarditis during the period before (11/1/2020 - 2/16/2021) and after (2/17/20121 - 3/31/2022) SARS-CoV-2 vaccines were available. Myocardial and axillary FDG uptake were quantitatively assessed using maximum standardized uptake value (SUVmax). SUVmax values in all patients and in patients stratified by sex (male/female), age (<40, 41-60, >60 years), and time interval between vaccination and PET/CT were compared using Mann-Whitney U test or Kruskal-Wallis test with post ad -hoc Dwass, Steel, Critchlow-Fligner multiple comparison analysis. Results The study included 303 nonvaccinated patients (mean age, 52.9 years ± 14.9 [SD]; 157 females) and 700 vaccinated patients (mean age, 56.8 years ± 13.7 [SD]; 344 females). Vaccinated patients had overall higher myocardial FDG uptake compared to nonvaccinated patients (median SUVmax, 4.8 [IQR: 3.0-8.5] vs median SUVmax, 3.3 [IQR: 2.5-6.2]; P < .0001). Myocardial SUVmax was higher in vaccinated patients regardless of sex (median range, 4.7-4.9 [IQR: 2.9-8.6]) or patient age (median range, 4.7-5.6 [IQR: 2.9-8.6]) compared to corresponding nonvaccinated groups (sex median range, 3.2-3.9 [IQR: 2.4-7.2]; age median range, 3.3-3.3 [IQR: 2.3-6.1]; P range, <.001-.015). Furthermore, increased myocardial FDG uptake was observed in patients imaged 1-30, 31-60, 61-120, and 121-180 days after their second vaccination (median SUVmax range, 4.6-5.1 [IQR: 2.9-8.6]) and increased ipsilateral axillary uptake was observed in patients imaged 1-30, 31-60, 61-120 days after their 2nd vaccination (median SUVmax range, 1.5-2.0 [IQR: 1.2-3.4]) compared to the nonvaccinated patients (P range, <.001-<.001). Conclusion Compared to nonvaccinated patients, asymptomatic patients who received their 2nd vaccination 1-180 days prior to imaging showed increased myocardial FDG uptake on PET/CT. See also the editorial by Bluemke in this issue.

Clinical utilization of artificial intelligence-based COVID-19 pneumonia quantification using chest computed tomography - a multicenter retrospective cohort study in Japan.

BACKGROUND: Computed tomography (CT) imaging and artificial intelligence (AI)-based analyses have aided in the diagnosis and prediction of the severity of COVID-19. However, the potential of AI-based CT quantification of pneumonia in assessing patients with COVID-19 has not yet been fully explored. This study aimed to investigate the potential of AI-based CT quantification of COVID-19 pneumonia to predict the critical outcomes and clinical characteristics of patients with residual lung lesions. METHODS: This retrospective cohort study included 1,200 hospitalized patients with COVID-19 from four hospitals. The incidence of critical outcomes (requiring the support of high-flow oxygen or invasive mechanical ventilation or death) and complications during hospitalization (bacterial infection, renal failure, heart failure, thromboembolism, and liver dysfunction) was compared between the groups of pneumonia with high/low-percentage lung lesions, based on AI-based CT quantification. Additionally, 198 patients underwent CT scans 3 months after admission to analyze prognostic factors for residual lung lesions. RESULTS: The pneumonia group with a high percentage of lung lesions (N = 400) had a higher incidence of critical outcomes and complications during hospitalization than the low percentage group (N = 800). Multivariable analysis demonstrated that AI-based CT quantification of pneumonia was independently associated with critical outcomes (adjusted odds ratio [aOR] 10.5, 95% confidence interval [CI] 5.59-19.7), as well as with oxygen requirement (aOR 6.35, 95% CI 4.60-8.76), IMV requirement (aOR 7.73, 95% CI 2.52-23.7), and mortality rate (aOR 6.46, 95% CI 1.87-22.3). Among patients with follow-up CT scans (N = 198), the multivariable analysis revealed that the pneumonia group with a high percentage of lung lesions on admission (aOR 4.74, 95% CI 2.36-9.52), older age (aOR 2.53, 95% CI 1.16-5.51), female sex (aOR 2.41, 95% CI 1.13-5.11), and medical history of hypertension (aOR 2.22, 95% CI 1.09-4.50) independently predicted persistent residual lung lesions. CONCLUSIONS: AI-based CT quantification of pneumonia provides valuable information beyond qualitative evaluation by physicians, enabling the prediction of critical outcomes and residual lung lesions in patients with COVID-19.

Factors affecting the selection of eligible candidates for focal therapy for prostate cancer.

PURPOSE: Focal therapy (FT) is a treatment modality for prostate cancer that aims to reduce side effects. However, it remains difficult to select eligible candidates. We herein examined eligibility factors for hemi-ablative FT for prostate cancer. METHODS: We identified 412 patients who were diagnosed with unilateral prostate cancer by biopsy and had undergone radical prostatectomy between 2009 and 2018. Among these patients, 111 underwent MRI before biopsy, had 10-20 core biopsies performed, and did not receive other treatments before surgery. Fifty-seven patients with prostate-specific antigen ≥ 15 ng/mL and biopsy Gleason score (GS) ≥ 4 + 3 were excluded. The remaining 54 patients were evaluated. Both lobes of the prostate were scored using Prostate Imaging Reporting and Data System version 2 on MRI. Ineligible patients for FT were defined as those with ≥ 0.5 mL GS6 or GS ≥ 3 + 4 in the biopsy-negative lobe, ≥ pT3, or lymph node involvement. Selected predictors of eligibility for hemi-ablative FT were analyzed. RESULTS: Among our cohort of 54 patients, 29 (53.7%) were eligible for hemi-ablative FT. A multivariate analysis identified a PI-RADS score < 3 in the biopsy-negative lobe (p = 0.016) as an independent predictor of eligibility for FT. Thirteen out of 25 ineligible patients had GS ≥ 3 + 4 tumors in the biopsy-negative lobe, half of whom (6/13) also had a PI-RADS score < 3 in the biopsy-negative lobe. CONCLUSION: The PI-RADS score in the biopsy-negative lobe may be important in the selection of eligible candidates for FT. The findings of this study will help reduce missed significant prostate cancers and improve FT outcomes.

Impact of patient characteristic factors on the dynamics of liver glucose metabolism: Evaluation of multiparametric imaging with dynamic whole-body 18 F-fluorodeoxyglucose-positron emission tomography.

AIMS: To assess the impact of various patient characteristics on the dynamics of liver glucose metabolism using automated multiparametric imaging with whole-body dynamic 18 F-fluorodeoxyglucose (FDG)-positron emission tomography (PET). MATERIALS AND METHODS: We retrospectively enrolled 540 patients who underwent whole-body dynamic FDG-PET. Three quantitative indices representing hepatic glucose metabolism [mean standardized uptake value normalized by lean body mass (SULmean), metabolic glucose rate (kinetic index) and distribution volume (DV)] were measured from multiparametric PET images produced automatically based on the Patlak plot model. Patient characteristics including age, sex, body mass index, fasting time, blood glucose level, and the presence of diabetes mellitus (DM) or hepatic steatosis (HS) were collected. We examined the correlations between the characteristic factors and three quantitative indices using multiple regression analysis. RESULTS: The success rate of kinetic analysis using multiparametric PET imaging was 93.3% (504/540). Hepatic SULmean was significantly correlated with age (p < .001), sex (p < .001) and blood glucose level (p = .002). DV was significantly correlated with age (p = .033), sex (p < .001), body mass index (p = .002), fasting time (p = .043) and the presence of HS (p = .002). The kinetic index was significantly correlated with age (p < .001) and sex (p = .004). In the comparison of the healthy, DM and HS groups, patients with DM had a significantly increased SULmean, whereas patients with HS had a significantly decreased DV. CONCLUSIONS: Our results showed that liver glucose metabolism was influenced by various patient characteristic factors. Multiparametric FDG-PET imaging can be used to analyse the kinetics of liver glucose metabolism in routine clinical practice.

Estimating right atrial pressure using upright computed tomography in patients with heart failure.

OBJECTIVES: Upright computed tomography (CT) can detect slight changes particularly in the superior vena cava (SVC) volume in healthy volunteers under the influence of gravity. This study aimed to evaluate whether upright CT-based measurements of the SVC area are useful for assessing mean right atrial pressure (mRAP) in patients with heart failure. METHODS: We performed CT in both standing and supine positions to evaluate the SVC (directly below the junction of the bilateral brachiocephalic veins) and inferior vena cava (IVC; at the height of the diaphragm) areas and analyzed their relationship with mRAP, measured by right heart catheterization in 23 patients with heart failure. RESULTS: The median age of enrolled patients was 60 (51-72) years, and 69.6% were male. The median mRAP was 3 (1-7) mmHg. The correlations between the standing position SVC and IVC areas and mRAP were stronger than those in the supine position (SVC, ρ = 0.68, p < 0.001 and ρ = 0.43, p = 0.040; IVC, ρ = 0.57, p = 0.005 and ρ = 0.46, p = 0.026; respectively). Furthermore, the SVC area in the standing position was most accurate in identifying patients with higher mRAP (> 5 mmHg) (SVC standing, area under the receiver operating characteristic curve [AUC] = 0.91, 95% confidence interval [CI], 0.77-1.00; SVC supine, AUC = 0.78, 95% CI, 0.59-0.98; IVC standing, AUC = 0.77, 95% CI, 0.55-0.98; IVC supine, AUC = 0.72, 95% CI, 0.49-0.94). The inter- and intraobserver agreements (evaluated by intraclass correlation coefficients) for all CT measurements were 0.962-0.991. CONCLUSIONS: Upright CT-based measurement of the SVC area can be useful for non-invasive estimation of mRAP under the influence of gravity in patients with heart failure. KEY POINTS: • This study showed that the superior vena cava (SVC) area in the standing position was most accurate in identifying patients with heart failure with higher mean right atrial pressure. • Upright computed tomography-based measurements of the SVC area can be a promising non-invasive method for estimating mean right atrial pressure under the influence of gravity in patients with heart failure. • Clinical management of patients with heart failure based on this non-invasive modality may lead to early assessment of conditional changes and reduced hospitalization for exacerbation of heart failure.

Pediatric Ribs at Chest Radiography: Normal Variants and Abnormalities.

Normal variants and abnormalities of the ribs are frequently encountered on chest radiographs. Accurate identification of normal variants is crucial to avoid unnecessary investigations. A meticulous evaluation of rib abnormalities can provide valuable insights into the patient's symptoms, and even when no osseous condition is suspected, rib abnormalities may offer critical clues to underlying conditions. Rib abnormalities are associated with various conditions, including benign tumors, malignant tumors, infectious and inflammatory conditions, vascular abnormalities, metabolic disorders, nonaccidental injuries, malformation syndromes, and bone dysplasias. Abnormalities of the ribs are classified into three groups based on their radiographic patterns: focal, multifocal, and diffuse changes. Focal lesions are further subdivided into nonaggressive lesions, aggressive lesions, and infectious and inflammatory disorders. Radiologists should be aware of individual disorders of the pediatric ribs, including their imaging findings, relevant clinical information, and underlying pathogenesis. Differential diagnoses are addressed as appropriate. Since chest radiographs can suffice for diagnosis in certain cases, the authors emphasize a pattern recognition approach to radiographic interpretation. However, additional cross-sectional imaging may be necessary for focal lesions such as tumors or inflammatory conditions. Awareness of disease-specific imaging findings helps ascertain the nature of the lesion and directs appropriate management. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

CT in osteoarthritis: its clinical role and recent advances.

Computed tomography (CT) is a widely available imaging method and considered as one of the most reliable techniques in bone assessment. Although CT has limited tissue contrast and needs radiation exposure, it has several advantages like fast scanning time and high spatial resolution. In this regard, CT has unique roles in osteoarthritis (OA) and its variable utilities have been reported. Hence, this review highlights the clinical role of CT in OA of representative joints. In addition, CT showed the several technical advancements recently, for example, acquiring the CT image with standing, obtaining the dual-energy data, and novel photon-counting detector development. Therefore, the recent studies and potential utility of these new CT systems in OA are also discussed.

Changes in the lumbar intervertebral foramen between supine and standing posture in patients with adult spinal deformity: a study with upright computed tomography.

OBJECTIVE: To quantitatively assess the impact of supine and standing positions on the morphological changes in the lumbar intervertebral foramen (LIF) in patients with adult spinal deformity (ASD) using upright CT and conventional supine CT. MATERIALS AND METHODS: Thirty patients with ASD were prospectively enrolled in this study. All subjects underwent standing whole spine posterior/anterior radiographs, lateral radiographs, and whole spine CT, both in the supine and upright standing positions. Two orthopedic surgeons independently measured nine radiographic parameters in the radiograph and the lumbar foraminal area (FA) and height (FH) in supine and upright CT. Statistical analyses were performed to evaluate the risk of LIF decrease when standing upright compared to the supine position. The chi-squared, t test, Pearson's coefficients, intra- and inter-rater reliabilities, and ROC curves were calculated. The level of significance was set at p < 0.05. RESULTS: Among the 300 LIFs, both the lumbar FA and FH were either increased or decreased by > 5% in approximately 30% of LIFs each. The FA decreased in the lower lumbar spine. The concave side had a significantly higher rate of decreased FA and FH than the convex side (p < 0.05 and < 0.05, respectively). ROC analysis showed that narrowing of the intervertebral disc (cutoff > 0.05°) is a risk factor for decreased FA and FH. CONCLUSIONS: This study describes the details of the changes in the neuroforamen using a novel upright CT. In patients with ASD, approximately 30% of LIFs either increased or decreased in size by > 5% when standing. The risk factors for LIF decrease are the lower lumbar spine, concave side, and narrow side of the disc wedge.

Basic Consideration for Facial Aging: Age-Related Changes of the Bony Orbit and Orbicularis Oculi Muscle in East Asians.

BACKGROUND: Age-related changes in the periocular areas are mainly caused by anatomic changes of the bony orbit and orbicularis oculi muscle (OOM). To achieve effective rejuvenation, it is necessary to understand the age-related aspects of these anatomic changes. OBJECTIVES: The aim of this study was to analyze the configuration of the bony orbit and OOM with computed tomography (CT) and to evaluate the effects of aging on these structures. METHODS: A total of 220 orbits and OOMs of 110 Japanese participants (55 males, 55 females) aged 20 to 87 years were enrolled. The long diameter of the orbits, orbital ellipticity, OOM thickness, and OOM attachment to the inferior orbital rim were analyzed. These variables were statistically evaluated for their relationship with age. RESULTS: The long diameter of the orbit was significantly longer in those over than in those under 60 years, with a moderate and significant positive correlation between orbital ellipticity and age. OOM thickness and age showed a strong negative correlation. The degree of OOM attachment to the inferior orbital rim decreased significantly with age. CONCLUSIONS: This study showed that age-related changes of the bony orbit in Japanese individuals tended to be the same as those in Caucasians, but there were differences in the degree of changes observed. As a new finding in the Japanese population, the OOM not only thins with aging, but also gradually loosens from the facial bone. In the elderly, only the nasal side of the OOM was attached to the bone. In clinical applications, this knowledge could contribute to the development of cosmetic surgeries.

Traction Bronchiectasis/Bronchiolectasis on CT Scans in Relationship to Clinical Outcomes and Mortality: The COPDGene Study.

Background The clinical impact of interstitial lung abnormalities (ILAs) on poor prognosis has been reported in many studies, but risk stratification in ILA will contribute to clinical practice. Purpose To investigate the association of traction bronchiectasis/bronchiolectasis index (TBI) with mortality and clinical outcomes in individuals with ILA by using the COPDGene cohort. Materials and Methods This study was a secondary analysis of prospectively collected data. Chest CT scans of participants with ILA for traction bronchiectasis/bronchiolectasis were evaluated and outcomes were compared with participants without ILA from the COPDGene study (January 2008 to June 2011). TBI was classified as follows: TBI-0, ILA without traction bronchiectasis/bronchiolectasis; TBI-1, ILA with bronchiolectasis but without bronchiectasis or architectural distortion; TBI-2, ILA with mild to moderate traction bronchiectasis; and TBI-3, ILA with severe traction bronchiectasis and/or honeycombing. Clinical outcomes and overall survival were compared among the TBI groups and the non-ILA group by using multivariable linear regression model and Cox proportional hazards model, respectively. Results Overall, 5295 participants (median age, 59 years; IQR, 52-66 years; 2779 men) were included, and 582 participants with ILA and 4713 participants without ILA were identified. TBI groups were associated with poorer clinical outcomes such as quality of life scores in the multivariable linear regression model (TBI-0: coefficient, 3.2 [95% CI: 0.6, 5.7; P = .01]; TBI-1: coefficient, 3.3 [95% CI: 1.1, 5.6; P = .003]; TBI-2: coefficient, 7.6 [95% CI: 4.0, 11; P < .001]; TBI-3: coefficient, 32 [95% CI: 17, 48; P < .001]). The multivariable Cox model demonstrated that ILA without traction bronchiectasis (TBI-0-1) and with traction bronchiectasis (TBI-2-3) were associated with shorter overall survival (TBI-0-1: hazard ratio [HR], 1.4 [95% CI: 1.0, 1.9; P = .049]; TBI-2-3: HR, 3.8 [95% CI: 2.6, 5.6; P < .001]). Conclusion Traction bronchiectasis/bronchiolectasis was associated with poorer clinical outcomes compared with the group without interstitial lung abnormalities; TBI-2 and 3 were associated with shorter survival. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Lee and Im in this issue.

Comparison of Foaming Properties Between the Shirasu Porous Glass Membrane Device and Tessari's Three-way Stopcock Technique for Polidocanol and Ethanolamine Oleate Foam Production: A Benchtop Study.

PURPOSE: To compare the characteristics of polidocanol (POL) and ethanolamine oleate (EO) sclerosing foams produced by a Shirasu porous glass membrane (SPGM) device with those made using a 3-way stopcock (3WSC). MATERIALS AND METHODS: Foam half-life times were measured in an ex-vivo benchtop study. Computed tomography (CT) images of each foam were obtained over the time course, and a CT texture analysis was conducted. The bubble size in each foam was measured by an optical microscope. RESULTS: Median foam half-life times were longer in the SPGM group than in the 3WSC group (POL: 198 vs 166 s, P = .02; EO: 640 vs 391 s, P < .01). In the CT texture analysis, median standard deviation (SD) and entropy (randomness) were lower, and median energy (uniformity) and gray-level cooccurrence matrix (GLCM) homogeneity were higher in the SPGM group than in the 3WSC group (POL SD: at 30 s and 50-300 s; POL entropy: at 0-60 s; EO SD: at 0-600 s; EO entropy: at 0-460 s; POL energy: at 0-40 s; POL GLCM homogeneity: at 0-250 s; EO energy: at 0-360 s; EO GLCM homogeneity: at 0-480 s; all P < .05). Median bubble diameters in the SPGM group and in the 3WSC group were 69 and 83 µm (P < .01), respectively, in the POL foam; and 36 and 36 µm (P = .45), respectively, in the EO foam. CONCLUSIONS: POL and EO foams had greater uniformity and longer foam half-life time when prepared with an SPGM device than with a 3WSC.

Effect of Ultra-High-Resolution CT on Pseudoenhancement in Renal Cysts: A Phantom Experiment and Clinical Study.

BACKGROUND. Ultra-high-resolution CT (UHRCT) allows acquisition using a small detector element size, in turn allowing very high spatial resolutions. The high resolution may reduce partial-volume averaging and thereby renal cyst pseudoenhancement. OBJECTIVE. The purpose of this article was to assess the impact of UHRCT on renal cyst pseudoenhancement. METHODS. A phantom was constructed that contained 7-, 15-, and 25-mm simulated cysts within compartments simulating unenhanced and nephrographic phase renal parenchyma. The phantom underwent two UHRCT acquisitions using 0.25- and 0.5-mm detector elements, with reconstruction at varying matrices and slice thicknesses. A retrospective study was performed of 36 patients (24 men, 12 women; mean age, 75.7 ± 9.4 [SD] years) with 118 renal cysts who underwent renal-mass protocol CT using UHRCT and the 0.25-mm detector element, with reconstruction at varying matrices and slice thicknesses; detector element size could not be retrospectively adjusted. ROIs were placed to measure cysts' attenuation increase from unenhanced to nephrographic phases (to reflect pseudoenhancement) and SD of unenhanced phase attenuation (to reflect image noise). RESULTS. In the phantom, attenuation increase was lower for the 0.25- than 0.5-mm detector element for the 15-mm cyst (4.6 ± 2.7 HU vs 6.8 ± 2.9 HU, p = .03) and 25-mm cyst (2.3 ± 1.4 HU vs 3.8 ± 1.2 HU, p = .02), but not the 7-mm cyst (p = .72). Attenuation increase was not different between 512 × 512 and 1024 × 1024 matrices for any cyst size in the phantom or patients (p > .05). Attenuation increase was not associated with slice thickness for any cyst size in the phantom or in patients for cysts that were between 5 mm and less than 10 mm and those that were 10 mm and larger (p > .05). For cysts smaller than 5 mm in patients, attenuation increase showed decreases with thinner slices, though there was no significant difference between 0.5-mm and 0.25-mm (3-mm slice: 23.7 ± 22.5 HU; 2-mm slice: 20.2 ± 22.7 HU; 0.5-mm slice: 11.6 ± 17.5 HU; 0.25-mm slice: 12.6 ± 19.7 HU; p < .001). Smaller detector element size, increased matrix size, and thinner slices all increased image noise for cysts of all sizes in the phantom and patients (p < .05). CONCLUSION. UHRCT may reduce renal cyst pseudoenhancement through a smaller detector element size and, for cysts smaller than 5 mm, very thin slices; however, these adjustments result in increased noise. CLINICAL IMPACT. Although requiring further clinical evaluation, UHRCT may facilitate characterization of small cystic renal lesions, thereby reducing equivocal interpretations and follow-up recommendations.

Multisystem Imaging Manifestations of Kawasaki Disease.

Kawasaki disease (KD) is a common pediatric vasculitis syndrome involving medium- and small-sized arteries that is especially prevalent in early childhood (ie, age 6 months to 5 years). The diagnosis of KD is made on the basis of clinical features, such as fever, characteristic mucocutaneous changes, and nonsuppurative cervical lymphadenopathy. However, early diagnosis is often challenging because many children with KD present with atypical symptoms. The most serious complication of KD is coronary artery aneurysm caused by coronary arteritis. Prompt intravenous immunoglobulin therapy reduces the risk of cardiac morbidity. In addition, the systemic extension of KD-related vasculitis during the acute phase causes a variety of multisystem manifestations, including encephalopathy, stroke, retropharyngeal edema, pericarditis, myocarditis, KD shock syndrome, pulmonary lesions, intestinal pseudo-obstruction, gallbladder hydrops, arthritis, and myositis. These complications tend to be more common in affected children with atypical presentation. Radiologists can play an important role in the timely identification of diverse KD-associated morbidities and thus may contribute to the early diagnosis of atypical KD. Online supplemental material is available for this article. ©RSNA, 2021.

Comparison of Lung, Lobe, and Airway Volumes between Supine and Upright Computed Tomography and Their Correlation with Pulmonary Function Test in Patients with Chronic Obstructive Pulmonary Disease.

BACKGROUND: Correlations between upright CT and pulmonary function test (PFT) measurements, and differences in lung/lobe/airway volumes between supine and standing positions in patients with chronic obstructive pulmonary disease (COPD) remain unknown. OBJECTIVES: The study aimed to evaluate correlations between lung/airway volumes on both supine and upright CT and PFT measurements in patients with COPD, and compare CT-based inspiratory/expiratory lung/lobe/airway volumes between the two positions. METHODS: Forty-eight patients with COPD underwent both conventional supine and upright CT in a randomized order during inspiration and expiration breath-holds, and PFTs within 2 h. We measured the lung/lobe/airway volumes on both CT. RESULTS: The correlation coefficients between total lung volumes on inspiratory CT in supine/standing position and PFT total lung capacity and vital capacity were 0.887/0.920 and 0.711/0.781, respectively; between total lung volumes on expiratory CT in supine/standing position and PFT functional residual capacity and residual volume, 0.676/0.744 and 0.713/0.739, respectively; and between airway volume on inspiratory CT in supine/standing position and PFT forced expiratory volume in 1 s, 0.471/0.524, respectively. Inspiratory/expiratory bilateral upper and right lower lobe, bilateral lung, and airway volumes were significantly higher in the standing than supine position (3.6-21.2% increases, all p < 0.05); however, inspiratory/expiratory right middle lobe volumes were significantly lower in the standing position (4.6%/15.9% decreases, respectively, both p < 0.001). CONCLUSIONS: Upright CT-based volumes were more correlated with PFT measurements than supine CT-based volumes in patients with COPD. Unlike other lobes and airway, inspiratory/expiratory right middle lobe volumes were significantly lower in the standing than supine position.

Clinical Utility of the Electrocardiographic P-Wave Axis in Patients with Chronic Obstructive Pulmonary Disease.

BACKGROUND: The vertical P-wave axis on electrocardiography (ECG) is a useful criterion for screening patients with chronic obstructive pulmonary disease (COPD). This study aimed to investigate the clinical characteristics of patients with COPD with a vertical P-wave axis as they have not yet been elucidated. METHODS: Keio University and its affiliated hospitals conducted an observational COPD cohort study over 3 years. We analyzed 201 patients using ECG and chest computed tomography. RESULTS: The severity of airflow limitation was higher in patients with a P-wave axis >75° than in those with a P-wave axis ≤75°. Patients with a P-wave axis >75° exhibited significantly higher total COPD assessment test scores and increased St. George's Respiratory Questionnaire total, activity, and impact scores than those with a P-wave axis ≤75°. The incidence of exacerbations over 1 and 3 years was significantly higher in patients with a P-wave axis >75° than in those with a P-wave axis ≤75°. The optimal cutoff for the P-wave axis for a percentage of the predicted forced expiratory volume in 1 s <50% and future exacerbations over 3 years was 70° (the areas under the curve [AUC]: 0.788; sensitivity: 65.3%; specificity: 78.3%) and 79° (AUC: 0.642; sensitivity: 36.7%; specificity: 92.6%). The ratio of the low attenuation area was also significantly higher in patients with a P-wave axis >75° than in those with a P-wave axis ≤75°. However, the ratio of the airway wall area did not differ between the 2 groups. CONCLUSIONS: Patients with COPD with a vertical P-wave axis exhibited severe airflow limitation and emphysema, a worse health status, and more frequent exacerbation than patients without a vertical P-wave. Detection of the vertical P-wave axis by ECG is beneficial for the management of patients with COPD.

Relationship between hip joint proximity area and sagittal balance parameters: an upright computed tomography study.

PURPOSE: A close relationship between sagittal spinal alignment and hip osteoarthritis (OA) has been documented. This study aimed to examine the relationship between hip joint proximity area and sagittal balance parameters in healthy subjects. METHODS: This prospective study enrolled 47 healthy volunteers who underwent 320-detector row upright computed tomography. Acquired data were reconstructed in a virtual three-dimensional space. The proximity area was determined by < 1 mm of the Hausdorff distance between the acetabulum and the femoral head. Volunteers were divided into the anterior and posterior proximity groups depending on the position of the closest area. Sagittal balance parameters [sagittal vertical axis (SVA), T1 spinopelvic inclination (T1-SPi), T1-pelvic angle, pelvic tilt, sacral slope, pelvic incidence, lumbar lordosis, thoracic kyphosis), offset distance between the centre of the acoustic meati (CAM) and C7 plumb line (CAM-C7-offset), and offset distance between the CAM and hip axis (HA) (CAM-HA-offset)] were compared between the two groups using independent sample t test. RESULTS: The anterior proximity group (n = 24) had higher SVA (p = 0.016) and T1-Spi (p = 0.015) than the posterior proximity group (n = 23). CAM-HA-offset was higher in the posterior than in the anterior proximity group (p < 0.000). There was no difference in other parameters (p > 0.05). CONCLUSION: The anterior proximity group had a positive anterior spinal balance; the posterior proximity group may have a more posterior gravity line than the hip joint centre. The anterior spinal balance may contribute to the anterior loading of the hip joint, with known relation with the initiation and onset of hip OA.