Right ventricular scalloping index as cardiac magnetic resonance-derived marker for diagnosis of arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND: The cardiac magnetic resonance (CMR) evaluation of right ventricular (RV) morphologic abnormalities in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) is subjective. Here, we aimed to use a quantitative index, the right ventricular scalloping index (RVSI), to standardize the measurement of RV free wall scalloping and aid in the imaging diagnosis. METHODS: We retrospectively included 15 patients with definite ARVC and 45 age- and sex-matched patients with idiopathic right ventricular outflow tract ventricular arrhythmia (RVOT-VA) as controls. The RVSI was measured from cine images on four-chamber view to evaluate its ability to distinguish between ARVC and RVOT-VA patients. Other cardiac functional parameters including strain analysis were also performed. RESULTS: The RVSI was significantly higher in the ARVC than RVOT-VA group (1.56 ± 0.23 vs 1.30 ± 0.08, p < 0.001). The diagnostic performance of the RVSI was superior to the RV global longitudinal, circumferential, and radial strains, RV ejection fraction, and RV end-diastolic volume index. The RVSI demonstrated high intraobserver and interobserver reliability (intraclass correlation coefficient, 0.94 and 0.96, respectively). RVSI was a strong discriminator between ARVC and RVOT-VA patients (area under curve [AUC], 0.91; 95% CI, 0.82-0.99). A cutoff value of RVSI ≥1.49 provided an accuracy of 90.0%, specificity of 97.8%, sensitivity of 66.7%, positive predictive value (PPV) of 90.9%, and a negative predictive value (NPV) of 89.8%. In a multivariable analysis, a family history of ARVC or sudden cardiac death (odds ratio, 38.71; 95% CI, 1.48-1011.05; p = 0.028) and an RVSI ≥1.49 (odds ratio, 64.72; 95% CI, 4.58-914.63; p = 0.002) remained predictive of definite ARVC. CONCLUSION: RVSI is a quantitative method with good performance for the diagnosis of definite ARVC.

Who Is at Risk? A Critical Case of Japanese Encephalitis.

Japanese encephalitis (JE) is critical epidemic encephalitis caused by the JE virus (JEV) in Southeast Asia. The World Health Organization defined "acute encephalitis syndrome" (AES) as an acute onset of fever with a change of mental status and/or new-onset seizure, mainly for the surveillance of JE. The key clues for the diagnosis include the patient age group of unvaccinated era or waning vaccine-induced immunity and the history of possible mosquito bites in epidemic areas. We report a 47-year old man who is in an unvaccinated era with potential waning immunity. The patient presented with fever and altered mental status for 2 days. He was speechless and could not follow commands. The patient had gone camping in the countryside a week before the visit. At the emergency department, neck stiffness was noted. There was a leukocytosis with a left shift by blood cell count. The brain computed tomography was essentially normal. The cerebrospinal fluid (CSF) sample via lumbar puncture showed leukocytosis, a high protein level, and a low sugar level in comparison to serum tests. Further antibody test of CSF confirmed the diagnosis. Magnetic resonance imaging (MRI) of the brain revealed a high signal in the right thalamus and a mildly swollen left caudate nucleus 4 days after admission. He was extubated and finally discharged with partial dependency on activities of daily living. This case reminds us of the JE in AES. Emergency physicians should be aware of the suspicious case of unvaccinated age or waning immunity and possible mosquito bites in epidemic areas. The role of MRI on JE was also discussed in this article.