Development of a movable 4πβ(LS)-γ coincidence counting system for activity standardization of β-γ emitters

A new movable 3PM-γ coincidence system, based on 4πβ(LS)-γ coincidence counting, for activity measurement of β-γ emitters has been designed at the Korea Research Institute of Standards and Science (KRISS). The system incorporates 3 PM tubes on the plane and two detectors placed above and below the center of the plane. The 3 PM tubes for β-counters in the plane are movable up to 100 mm from a liquid scintillation vial, thus enabling the variation of β-detection efficiencies by a geometrical technique. A NaI(Tl) γ-counter was set above for the present work. The β-event is determined by counting the logical sum of three double coincidences. All the necessary electronics, i.e., logical sum, adjusting the duration of dead-time of each counting channel and coincidence resolving times, and analyzing coincidence relation, were specially designed to be fabricated in an integrated circuit. Details of the detectors, the electronics, the overall movable 3PM-γ coincidence system are presented, as well as the results of investigations to assess its operating characteristics. Validation measurements have been performed with ⁶⁰Co and ⁵⁷Co sources. The highest β-detection efficiency achieved with ⁶⁰Co and ⁵⁷Co was 97% and 95%, respectively. The activity concentration determined with a new system agreed with calibrated values within the uncertainty range. Further results from validation measurements and the corresponding uncertainty budgets are presented.

Observation of Coulomb-Assisted Nuclear Bound State of Ξ^{-}-^{14}N System

In an emulsion-counter hybrid experiment performed at J-PARC, a Ξ^{-} absorption event was observed which decayed into twin single-Λ hypernuclei. Kinematic calculations enabled a unique identification of the reaction process as Ξ^{-}+^{14}N→_{Λ}^{10}Be+_{Λ}^{5}He. For the binding energy of the Ξ^{-} hyperon in the Ξ^{-}-^{14}N system a value of 1.27±0.21  MeV was deduced. The energy level of Ξ^{-} is likely a nuclear 1p state which indicates a weak ΞN-ΛΛ coupling.

Predictive factors of recurrence after resection of subsolid clinical stage IA lung adenocarcinoma

BACKGROUND

Ongoing studies are currently investigating the extent of surgical resection required for subsolid cancers. This study aimed to investigate the predictive factors related to recurrence in patients with clinical stage IA subsolid cancer who underwent either lobectomy or sublobar resection.

METHODS

This was a prospective multicenter observational study conducted in eight qualifying university teaching hospitals between April 2014 and December 2016. A total of 173 patients with subsolid nodules pathologically confirmed to have primary lung adenocarcinoma and stage IA disease were included in the final analysis. All patients underwent lobectomy, segmentectomy, or wedge resection performed by experienced thoracoscopic surgeons at each site. The surgical procedure was chosen based on the decision of the surgeons involved. The primary endpoint was time to recurrence (TTR).

RESULTS

The study population was 43.9% (76 of 173) male with a mean age of 60.7 years. During the median follow-up period of 5.01 years, nine patients (5%) experienced disease recurrence. In the multivariable analysis, tumor size (size ≥2 cm) (hazard ratio: 73.717, 95% confidence interval [CI]: 3.635-895.036; p < 0.001) and stage IA3 (hazard ratio: 62.010, 95% CI: 2.837-855.185; p < 0.001) were independent predictors of tumor recurrence. When analyzing the recurrence outcome in patients according to surgical procedure, no significant difference was found in TTR among the three groups (i.e., lobectomy, segmentectomy, and wedge resection; p = 0.99).

CONCLUSIONS

Patients with radiologically subsolid lung adenocarcinoma measuring <3 cm could be candidates for sublobar resection instead of lobectomy.

Sarcopenia and visceral adiposity predict poor overall survival in hepatocellular carcinoma patients after curative hepatic resection

Background

This study investigated the association of 3 components of body composition (sarcopenia, intramuscular fat deposition and visceral adiposity) with the overall or recurrence-free survival of hepatocellular carcinoma (HCC) patients who underwent curative hepatic resection.

Methods

One hundred sixty newly diagnosed and surgically treated HCC patients were retrospectively enrolled from 2003 to 2011. Three items of body composition were measured using the 3^rd lumbar level image of preoperative computed tomography (CT): psoas muscle index (PMI), psoas muscle attenuation (PMA), and visceral adipose tissue index (VATI). Sex-specific optimal cut-off for each item was determined from receiver-operating characteristic curves.

Results

The HCC patients showed a median age of 55 years, 75% of male, 78% of hepatitis B surface antigen positivity, and 96% of Child-Pugh A. The sarcopenic group (PMI less than the sex-specific cutoff of 3.33 cm²/m² for men and 2.38 cm²/m² for women) had 17.5% of the patients with a lower PMA (more fat deposition) but similar VATI compared to the non-sarcopenic group. PMI showed a positive correlation with PMA (ρ=0.493, P<0.001), while there was no significant correlation between PMI and VATI, and between PMA and VATI. On the multivariate analysis, a high PMI and low VATI were independent factors affecting overall survival while PMA was not. Nevertheless, PMI and VATI were not independent factors for recurrence-free survival.

Conclusions

In curatively resected HCC patients, sarcopenia and high visceral adiposity predict poor overall survival but not recurrence-free survival, while PMA did not predict overall survival.

Blood flow volume of left atrial appendage measured by magnetic resonance imaging is improved after radiofrequency catheter ablation of atrial fibrillation

INTRODUCTION

Hemodynamics of left atrial appendage (LAA) is an important factor for future risk of ischemic stroke in atrial fibrillation (AF) patients. Velocity encoded cardiac magnetic resonance imaging (VENC-MRI) can evaluate blood flow volume of LAA without any invasive procedures. We aimed to evaluate the association between radiofrequency catheter ablation (RFCA) and LAA hemodynamics measured by MRI.

METHODS AND RESULTS

Consecutive RFCA cases in a single arrhythmia center were retrospectively analyzed. A total of 3120 AF patients who underwent first RFCA were analyzed. Among these patients 360 patients had both pre- and post-RFCA VENC-MRI evaluation. Atrial fibrillation was non-paroxysmal in 174 (48.3%) patients. Mean VENC-MRI (ml/sec) was significantly improved after RFCA with 49.93 ± 32.92 and 72.00 ± 34.82 for pre- and post-RFCA, respectively. Patients with non-paroxysmal AF (∆VENC-MRI = 14.63 ± 40.67 vs. 30.03 ± 35.37; p < .001) and low pre-RFCA VENC-MRI (∆VENC-MRI = 17.19 ± 38.35 vs. 50.35 ± 29.12; p < .001) had significantly higher improvement in VENC-MRI. Those who experienced late recurrence before post-RFCA MRI had significantly less improvement in LAA flow volume (∆VENC-MRI = 15.55 ± 41.41 vs. 26.18 ± 36.77; p = .011). Late recurrence and pre-RFCA VENC-MRI were significantly associated with ∆VENC-MRI after adjusting covariates. Patients who were AF before RFCA but maintained sinus rhythm after RFCA showed greatest improvement in VENC-MRI.

CONCLUSION

Effective rhythm control through RFCA can be associated with significant improvement in LAA hemodynamics. Low pre-RFCA VENC-MRI and absence of late recurrence were associated with greater improvement in LAA hemodynamics.

Effectiveness of 4-Week Oral Taurine Treatment for Muscle Cramps in Patients with Liver Cirrhosis: A Single-Arm Pilot Study

PURPOSE

Painful muscle cramps are a common complication in liver cirrhosis patients, and no effective treatment is available. This pilot study aimed to evaluate whether taurine supplementation improves muscle cramps in Korean cirrhotic patients.

MATERIALS AND METHODS

Ten cirrhotic patients who experienced muscle cramps one or more times/week were enrolled in this prospective single-arm study and administered with an oral taurine solution (1 g/50 mL) thrice a day for 4 weeks. Taurine was discontinued for the subsequent 4 weeks. The frequency and intensity of muscle cramps were evaluated using a questionnaire at weeks 0, 2, 4, 6, and 8 after the start of treatment.

RESULTS

At baseline, the median frequency of muscle cramps was six times/week, and all patients had severe pain. Muscle cramp scores (frequency×intensity) decreased in seven patients by weeks 4 and 8 after treatment initiation. Compared to baseline muscle cramp scores [median 21, interquartile range (IQR): 8-84], median muscle cramp scores were lower at week 4 (6.5, IQR: 3-12, p=0.126) and week 8 (5, IQR: 1.5-56, p=0.066). All five patients whose baseline plasma taurine levels were below the normal limit showed increased taurine levels at week 4; 60% of them experienced improvements in their muscle cramps. Of the five patients with normal or higher taurine levels, 80% experienced an improvement in symptoms at week 4. The safety and tolerability of the 4-week taurine therapy were excellent.

CONCLUSION

Oral taurine therapy for 4 weeks improved muscle cramps safely in cirrhotic patients.

Application of Dual-Energy Spectral Computed Tomography to Thoracic Oncology Imaging

Computed tomography (CT) is an important imaging modality in evaluating thoracic malignancies. The clinical utility of dual-energy spectral computed tomography (DESCT) has recently been realized. DESCT allows for virtual monoenergetic or monochromatic imaging, virtual non-contrast or unenhanced imaging, iodine concentration measurement, and effective atomic number (Z_eff map). The application of information gained using this technique in the field of thoracic oncology is important, and therefore many studies have been conducted to explore the use of DESCT in the evaluation and management of thoracic malignancies. Here we summarize and review recent DESCT studies on clinical applications related to thoracic oncology.

Evaluation of Left Atrial Appendage Isolation Using Cardiac MRI after Catheter Ablation of Atrial Fibrillation: Paradox of Appendage Reservoir

Objective

To assess the effect of left atrial appendage (LAA) isolation on LAA emptying and left atrial (LA) function using cardiac MRI in patients who underwent successful catheter ablation of atrial fibrillation (AF).

Materials and Methods

This retrospective study included 84 patients (mean age, 59 ± 10 years; 67 males) who underwent cardiac MRI after successful catheter ablation of AF. According to the electrical activity of LAA after catheter ablation, patients showed either LAA isolation or LAA normal activity. The LAA emptying phase (LAA-EP, in the systolic phase [SP] or diastolic phase), LAA emptying flux (LAA-EF, mL/s), and LA ejection fraction (LAEF, %) were evaluated by cardiac MRI.

Results

Of the 84 patients, 61 (73%) and 23 (27%) patients showed LAA normal activity and LAA isolation, respectively. Incidence of LAA emptying in SP was significantly higher in LAA isolation (91% vs. 0%, p < 0.001) than in LAA normal activation. LAA-EF was significantly lower in LAA isolation (40.1 ± 16.2 mL/s vs. 80.2 ± 25.1 mL/s, p < 0.001) than in LAA normal activity. Furthermore, LAEF was significantly lower in LAA isolation (23.7% ± 11.2% vs. 31.1% ± 16.6%, p = 0.04) than in LAA normal activity. Multivariate analysis demonstrated that the LAA-EP was independent from LAEF (p = 0.01).

Conclusion

LAA emptying in SP may be a critical characteristic of LAA isolation, and it may adversely affect the LAEF after catheter ablation of AF.

MG1113, a specific anti-tissue factor pathway inhibitor antibody, rebalances the coagulation system and promotes hemostasis in hemophilia

BACKGROUND

Replacement therapy is the most common treatment for reduction of bleeding and control of episodic bleeding in individuals with hemophilia. Despite the proven effectiveness of factor replacement therapy, repeated intravenous administration is a heavy burden to individuals with hemophilia.

OBJECTIVES

To reduce the burden, therapeutic agents that can be subcutaneously administered need to be developed, and an anti-tissue factor pathway inhibitor (TFPI) antibody may be a suitable candidate for this purpose.

METHODS

MG1113 is an IgG4 monoclonal antibody that binds to Kunitz-2 domain (KD2) of TFPI. To confirm the coagulation potential of MG1113, several tests were conducted using factor VIII (FVIII)- or IX (FIX)-deficient plasma. For the ex vivo spiking test, platelet-poor plasma samples from 14 individuals with hemophilia were spiked with MG1113. The in vivo efficacy was determined using blood loss tests, modified prothrombin time (mPT), and free TFPI quantification after intravenous or subcutaneous administration of MG1113 into hemophilia A (HA)-induced rabbits.

RESULTS

Radiographic crystallography demonstrated the specific binding site between MG1113 and KD2. In FVIII-deficient plasma and the plasma of individuals with hemophilia, peak thrombin and endogenous thrombin levels were increased by MG1113 in a concentration-dependent manner. Rotational thromboelastometry assay revealed that clotting time, clot formation time, and maximum clot firmness were normalized in MG1113-treated blood of patients. Intravenous or subcutaneous injection of MG1113 into HA-induced rabbits resulted in rebalancing of blood loss, mPT, and free TFPI levels.

CONCLUSIONS

These results indicate that subcutaneous administration of MG1113 neutralizes the function of TFPI and regulates bleeding in individuals with hemophilia.

Atrial Substrate Underlies the Recurrence after Catheter Ablation in Patients with Atrial Fibrillation

Prediction of recurrences after catheter ablation of atrial fibrillation (AF) remains challenging. We sought to investigate the long-term outcomes after AF catheter ablation. A total of 2221 consecutive patients who underwent catheter ablation for symptomatic AF were included in this study (mean age 55 ± 11 years, 20.3% women, and 59.0% paroxysmal AF). Extensive ablation, in addition to circumferential pulmonary vein isolation, was more often accomplished in patients with non-paroxysmal AF than in those with paroxysmal AF (87.4% vs. 25.3%, p < 0.001). During a median follow-up of 54 months, sinus rhythm (SR) was maintained in 67.1% after index procedure. After redo procedures in 418 patients, 83.3% exhibited SR maintenance. Recurrence rates were similar for single and multiple procedures (17.4% vs. 16.7%, p = 0.765). Subanalysis showed that the extent of late gadolinium enhancement (LGE), as assessed by cardiac magnetic resonance, is greater in patients with recurrence than in those without recurrence (36.2 ± 23.9% vs. 21.8 ± 13.7%, p < 0.001). Cox-regression analysis revealed that non-paroxysmal AF (hazard ratio (HR) 2.238, 95% confidence interval (CI) 1.905-2.629, p < 0.001), overweight (HR 1.314, 95% CI 1.107-1.559, p = 0.020), left atrium dimension ≥ 45 mm (HR 1.284, 95% CI 1.085-1.518, p = 0.004), AF duration (HR 1.020 per year, 95% CI 1.006-1.034, p = 0.004), and LGE ≥ 25% (HR 1.726, 95% CI 1.330-2.239, p < 0.001) are significantly associated with AF recurrence after catheter ablation. This study showed that repeated catheter ablation improves the clinical outcomes of patients with non-paroxysmal AF, suggesting that AF substrate based on LGE may underpin the mechanism of recurrence after catheter ablation.

Relationship between Coronary Iodine Concentration Determined Using Spectral CT and the Outcome of Percutaneous Coronary Intervention in Patients with Chronic Total Occlusion

PURPOSE

To evaluate the feasibility of coronary iodine concentration (CIC) by using spectral CT in the assessment of the outcome of percutaneous coronary intervention (PCI) for chronic total occlusion (CTO).

MATERIALS AND METHODS

In total, 50 consecutive patients underwent preprocedural coronary CT angiography with spectral CT prior to their staged PCI for CTO between June 2017 and July 2018. Iodine density maps, referred to as iodine-no-water maps throughout, with spectral CT provided the CIC at proximal CTO (CTO-CIC). Depending on the outcome of PCI, all CTO lesions were divided into two groups: failed PCI and successful PCI. The receiver operating characteristic curve was used to determine the cutoff values of CTO-CIC in the assessment of the outcome of PCI for CTO.

RESULTS

Of the 50 CTO lesions in 50 patients, 34 (68%) and 16 (32%) were assigned to the successful PCI and failed PCI groups, respectively. The mean CTO-CIC was significantly less in the failed PCI group than in the successful PCI group (1.3 mg/mL ± 0.9 [standard deviation] vs 5.2 mg/mL ± 2.5; P < .001). A low CTO-CIC (≤ 2.5 mg/mL) predicted failed PCI with 87% sensitivity, 79% specificity, 79% positive predictive value, and 90% negative predictive value. At multivariable analysis, the low CTO-CIC was significantly associated with the failed PCI (odds ratio, 27.0; 95% confidence interval: 4.9, 147.6; P < .0001).

CONCLUSION

The CTO-CIC determined by using spectral CT may be useful in the assessment of the outcome of staged PCI for CTO.See also the commentary by Rubinshtein and Blankstein in this issue.© RSNA, 2020.

The association of the serum levels of myostatin, follistatin, and interleukin-6 with sarcopenia, and their impacts on survival in patients with hepatocellular carcinoma

Background/Aims

The role of serum myokine levels in sarcopenia and the outcome of hepatocellular carcinoma (HCC) patients are not clear. This study investigated the serum levels of myostatin, follistatin, and interleukin-6 (IL-6) in HCC patients and their association with sarcopenia and survival.

Methods

Using prospectively collected pretreatment samples from 238 HCC patients in a hospital from 2012 to 2015, the serum levels of 3 myokines were determined and compared to 50 samples from age and sex-matched healthy controls. Sarcopenia was evaluated using the psoas muscle index (PMI) measured at the third lumbar level in the computed tomography, and clinical data were collected until 2017.

Results

The median levels of the 3 myokines for the male and female HCC patients were as follow: myostatin (3,979.3 and 2,976.3 pg/mL), follistatin (2,118.5 and 2,174.6 pg/mL), and IL-6 (2.5 and 2.7 pg/mL), respectively. Those in the HCC patients were all significantly higher than in the healthy controls. In the HCC patient, the median PMI was 4.43 (males) and 2.17 cm²/m² (females) with a sarcopenic prevalence of 56.4%. The serum levels of myostatin, IL-6 and follistatin in the HCC patients showed a positive, negative, and no correlation with PMI, respectively. The serum follistatin level was an independent factor for poor survival in HCC patients.

Conclusions

The serum levels of myostatin, follistatin, and IL-6 and their correlation with sarcopenia and survival were presented in HCC patients for the first time. The role of the serum follistatin level as a poor prognostic biomarker warrants further study.

A Stepwise Diagnostic Approach to Cystic Lung Diseases for Radiologists

Lung cysts are commonly seen on computed tomography (CT), and cystic lung diseases show a wide disease spectrum. Thus, correct diagnosis of cystic lung diseases is a challenge for radiologists. As the first diagnostic step, cysts should be distinguished from cavities, bullae, pneumatocele, emphysema, honeycombing, and cystic bronchiectasis. Second, cysts can be categorized as single/localized versus multiple/diffuse. Solitary/localized cysts include incidental cysts and congenital cystic diseases. Multiple/diffuse cysts can be further categorized according to the presence or absence of associated radiologic findings. Multiple/diffuse cysts without associated findings include lymphangioleiomyomatosis and Birt-Hogg-Dubé syndrome. Multiple/diffuse cysts may be associated with ground-glass opacity or small nodules. Multiple/diffuse cysts with nodules include Langerhans cell histiocytosis, cystic metastasis, and amyloidosis. Multiple/diffuse cysts with ground-glass opacity include pneumocystis pneumonia, desquamative interstitial pneumonia, and lymphocytic interstitial pneumonia. This stepwise radiologic diagnostic approach can be helpful in reaching a correct diagnosis for various cystic lung diseases.

The primary system for measurement of beta emitting radioactive gases at KRISS

Korea Research Institute of Standards and Science (KRISS) is developing a length-compensated proportional counting (LCPC) system as a primary system for standardization of beta emitting radioactive gases. The pilot experiment was performed with ⁸⁵Kr and the optimized high voltage and pressure were found to be 1700 V and 0.203 MPa, respectively. The total activity of ⁸⁵Kr was deduced by the length compensation of each count. The expanded uncertainty was estimated to be around 0.8% (k = 2) for the ⁸⁵Kr measurement.

Design of optimal digital filter and digital signal processing for a CdZnTe high resolution gamma-ray system

We have developed an online digital signal processing system based on an FPGA. The system consists of pile-up rejection, baseline restorer, peak detection and pole-zero cancellation for evaluation of deposited energy in the detector. The shaping algorithm employed is a Moving Window Deconvolution (MWD) to shape digitized data into a trapezoidal form. For the purpose of verification, the developed digital system was tested for ¹³⁷Cs gamma rays. The entire system is programmed using the LabVIEW environment.

How Different is the Core of ^{25}F from ^{24}O_{g.s.} ?

The structure of a neutron-rich ^{25}F nucleus is investigated by a quasifree (p,2p) knockout reaction at 270A  MeV in inverse kinematics. The sum of spectroscopic factors of π0d_{5/2} orbital is found to be 1.0±0.3. However, the spectroscopic factor with residual ^{24}O nucleus being in the ground state is found to be only 0.36±0.13, while those in the excited state is 0.65±0.25. The result shows that the ^{24}O core of ^{25}F nucleus significantly differs from a free ^{24}O nucleus, and the core consists of ∼35% ^{24}O_{g.s.}. and ∼65% excited ^{24}O. The result may infer that the addition of the 0d_{5/2} proton considerably changes neutron structure in ^{25}F from that in ^{24}O, which could be a possible mechanism responsible for the oxygen dripline anomaly.

Risk factors for primary lung cancer among never-smoking women in South Korea: a retrospective nationwide population-based cohort study

BACKGROUND/AIMS

We performed a large-scale, retrospective, nationwide, cohort study to investigate the risk factors for lung cancer among never-smoking Korean females.

METHODS

The study data were collected from a general health examination and questionnaire survey of eligible populations conducted between January 1, 2003 and December 31, 2004; the data were acquired from the tailored big data distribution service of the National Health Insurance Service. After a 1-year clearance period, 5,860,922 of 6,318,878 never-smoking female participants with no previous history of lung cancer were investigated. After a median follow-up of 11.4 years, 43,473 (0.74%) participants were defined as "newly diagnosed lung cancer".

RESULTS

After adjusting for all variables at baseline, the variables older age, lower body mass index (BMI), less exercise, frequent alcohol drinking, meat-based diet, rural residence, and previous history of cancer were associated with a higher incidence of lung cancer. Low BMI (< 18.5 kg/m2: hazard ratio [HR], 1.33; 95% confidence interval [CI], 1.27 to 1.40) was a significant independent risk factor; as BMI decreased, HR increased. Negative associations between BMI and lung-cancer development were also observed after controlling for age (p for trend < 0.001). Drinking alcohol one to two times a week (HR, 1.25; 95% CI, 1.21 to 1.28) and eating a meat-based diet (HR, 1.08; 95% CI, 1.01 to 1.15) were associated with lung-cancer incidence.

CONCLUSION

Modifiable baseline characteristics, such as BMI, exercise, alcohol consumption, and diet, are risk factors for lung-cancer development among never- smoking females. Thus, lifestyle modifications may help prevent lung cancer.

Indoor air concentrations of carbon dioxide (CO2), nitrogen dioxide (NO2), and ozone (O3) in multiple healthcare facilities

This study evaluates indoor air concentrations of CO₂, NO₂, and O₃ and their relationship to other indoor environmental factors in facilities with occupants susceptible to air contaminants, such as hospitals, senior specialized hospitals, elderly care facilities, and postnatal care centers. Indoor air samples were collected from 82 indoor facilities in South Korea and organized by region. Spearman's correlation and Kruskal-Wallis analyses were employed to examine the relationship among and differences between contaminants in the indoor facilities and indoor/outdoor differences of NO₂ and O₃ concentrations. Significant correlations were found between CO₂ and NO₂ concentrations (r² = 0.176, p < 0.01), as well as NO₂ and O₃ concentrations (r² = - 0.289, p < 0.0001). The indoor/outdoor concentration ratios in the indoor facilities were 0.73 for NO₂ and 0.25 for O₃. CO₂ and NO₂ displayed the highest mean concentrations during spring, while O₃ displayed the highest and lowest mean concentrations during fall and summer, respectively. The calculated hazard quotient (HQ) for NO₂ was higher than the acceptable level of 1 in postnatal care centers, thus posing a health risk for children. Study results indicate that efficient ventilation is required to reduce indoor contaminants in multiple healthcare facilities. This study provides a novel approach toward health risk assessment for indoor facilities with susceptible occupants on a large geographical scale.

Use of Cardiac Computed Tomography and Magnetic Resonance Imaging in Case Management of Atrial Fibrillation with Catheter Ablation

Atrial fibrillation (AF) is the most common arrhythmia associated with the risk of morbidity and mortality in clinical patients. AF is considered as an arrhythmia type that develops and progresses through close connection with cardiac structural arrhythmogenic substrates. Since the introduction of catheter ablation-mediated electrical isolation of arrhythmogenic substrates, cardiac imaging indicates improved treatment outcome and prognosis with appropriate candidate selection, ablation catheter guidance, and post-ablation follow-up. Currently, cardiac computed tomography (CCT) and cardiovascular magnetic resonance (CMR) imaging are essential in the case management of AF at both pre-and post-procedural stages of catheter ablation. In this review, we discuss the roles and technical considerations of CCT and CMR imaging in the management of patients with AF undergoing catheter ablation.

Assessment of Left Ventricular Myocardial Diseases with Cardiac Computed Tomography

Rapid advances in cardiac computed tomography (CT) have enabled the characterization of left ventricular (LV) myocardial diseases based on LV anatomical morphology, function, density, and enhancement pattern. Global LV function and regional wall motion can be evaluated using multi-phasic cine CT images. CT myocardial perfusion imaging facilitates the identification of hemodynamically significant coronary artery disease. CT delayed-enhancement imaging is used to detect myocardial scar in myocardial infarction and to measure the extracellular volume fraction in non-ischemic cardiomyopathy. Multi-energy cardiac CT allows the mapping of iodine distribution in the myocardium. This review summarizes the current techniques of cardiac CT for LV myocardial assessment, highlights the key findings in various myocardial diseases, and presents future applications to complement echocardiography and cardiovascular magnetic resonance.

Hook-wire localization versus lipiodol localization for patients with pulmonary lesions having ground-glass opacity

OBJECTIVES

Accurate and safe preoperative localization is useful for video-assisted thoracic surgery of small pulmonary lesions with ground-glass opacity (GGO). However, the optimal localization method is unclear. The aim of this study was to compare the usefulness and safety of the lipiodol and hook-wire localization techniques for video-assisted thoracic surgery of GGO lesions.

METHODS

This prospective, non-randomized comparative study was conducted between April 2014 and December 2016 at 8 qualifying university teaching hospitals. Two-hundred-fifty patients with pulmonary lesions having GGO were included. Patients were assigned in a 1:1 ratio to either the lipiodol (n = 125, 4 hospitals) or hook-wire group (n = 125, 4 hospitals) for preoperative localization procedures. Participants underwent preoperative localization via the lipiodol or hook-wire technique followed by thoracoscopic surgery. The primary endpoint was the procedure success rate.

RESULTS

The procedure success rates (hook-wire vs lipiodol group) were 94.40% versus 99.16% (P = .08). Localization-related complications occurred in 53.60% versus 48.33% of patients (P = .49). Hemorrhage rates were significantly greater in the hook-wire group than in the lipiodol group (21.6% vs 5.83%, P < .001). The lipiodol procedure time was significantly longer than that of the hook-wire technique (20.69 ± 9.34 vs 17.15 ± 7.91 minutes, P = .001). The initially positive surgical resection margin was significantly greater in the hook-wire group than in the lipiodol group (10.89% vs 2.38%, P = .02).

CONCLUSIONS

There was no significant difference in success rate between the hook-wire and lipiodol methods. However, the hemorrhage rate was significantly greater in the hook-wire group, whereas the hook-wire group showed greater initially positive surgical resection margins.

Left Atrial Fibrosis Assessed with Cardiac MRI in Patients with Paroxysmal and Those with Persistent Atrial Fibrillation

Background Electrophysiology studies have demonstrated that left atrial late gadolinium enhancement (LGE) is associated with the chronicity of atrial fibrillation (AF). To date, cardiac MRI has been used to assess the extent of atrial LGE but not the distribution pattern of LGE in the left atrium. Purpose To determine whether the MRI pattern of left atrial fibrosis is associated with the chronicity of AF. Materials and Methods This retrospective study included patients with AF who underwent LGE MRI between June 2017 and May 2018. The presence of left atrial LGE was assessed at nine left atrial segments; the extent was determined by the number of segments involved. According to the chronicity of AF, patients were separated into paroxysmal AF (PAF) and persistent AF (PeAF) groups. The location and extent of left atrial LGE were compared between PAF and PeAF by using the χ² test and logistic regression analysis. Results Of the 195 patients (mean age, 55 years ± 10 [standard deviation], 161 men), 74 (38%) had PAF and 121 (62%) had PeAF. Of all patients, 114 (58.4%) had at least one left atrial LGE segment. The mean number of LGE segments was higher (1.4 ± 1.1 vs 0.6 ± 0.7, P = .002) in the PeAF group than in the PAF group. The incidence of LGE at the left inferior pulmonary vein (LIPV) antrum was higher in the PeAF group than in the PAF group (39.2% [29 of 74] vs 7.4% [nine of 121]; P < .001). In multivariable analysis, LGE at the LIPV antrum was independently associated with PeAF (odds ratio = 4.2; 95% confidence interval: 1.7, 10.5; P < .001). Conclusion The presence of fibrosis assessed with late gadolinium enhancement MRI of the left inferior pulmonary vein antrum was associated with persistent atrial fibrillation. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Almeida in this issue.

Lifetime measurement of the first excited 5/2+ state in 133Cs using NaI(Tl) and LaBr3(Ce) detectors

We report a new high-precision lifetime measurement of the first excited 5/2⁺ state of ¹³³Cs using NaI(Tl) and LaBr₃(Ce) detectors. The time difference between the coincident decays of two successive states was measured using fast-timing electronics. The 356-keV (1/2⁺→5/2⁺) gamma transition was tagged by the successive 81-keV (5/2⁺→7/2⁺) transition of ¹³³Cs. The half-life of the first excited 5/2⁺¹³³Cs state was measured as T_1/2=6.283±0.004 (stat.) ±0.011(syst.) ns.