Diagnostic challenges from conflicting results of tests and imaging

Accurate diagnosis is the foundation of clinical care but accurate diagnosis is not easily reached in some cases.In rare instances,even a sophisticated multidisciplinary team at an academic medical center cannot reliably reach an accurate diagnosis after extensive testing and imaging,and has to wait until histological diagnosis or even autopsy results are available.The underlying reason of challenging diagnoses is mostly conflicting data from history,tests,and imaging that point to different diagnoses.In this issue of World Journal of Clinical Cases,Huffaker et al reported such a challenging case of a tricuspid mass in a patient with Li-Fraumeni syndrome.The case by Huffaker et al powerfully illustrates the occasional diagnostic challenges inherent in our current diagnostic approach and the current technology.Clinicians should realize that in rare situations,agnosticism in diagnosis is unavoidable but a treatment has to be initiated so long as the principle of primum non nocere is upheld.

Significance of inferior wall ischemia in non-dominant right coronary artery anatomy

AIM To investigate the relationship of inferior wall ischemia on myocardial perfusion imaging in patients with nondominant right coronary artery anatomy.METHODS This was a retrospective observational analysis of consecutive patients who presented to the emergency department with primary complaint of chest pain.Only patients who underwent single photon emission computed tomography(SPECT)myocardial perfusion imaging(MPI)were included.Patients who showed a reversible defect on SPECT MPI and had coronary angiography during the same hospitalization was analyzed.Patients with prior history of coronary artery disease(CAD)including history of percutaneous coronary intervention and coronary artery bypass graft surgerys were excluded.True positive and false positive results were identified on the basis of hemodynamically significant CAD on coronary angiography,in the same territory as identified on SPECT MPI.Coronary artery dominance was determined on coronary angiography.Patients were divided into group 1 and group 2.Group1 included patients with non-dominant right coronary artery(RCA)(left dominant and codominant).Group2 included patients with dominant RCA anatomy.Demographics,baseline characteristics and positive predictive value(PPV)were analyzed for the two groups.RESULTS The mean age of the study cohort was 57.6 years.Sixtyone point seven percent of the patients were males.The prevalence of self-reported diabetes mellitus,hypertension and dyslipidemia was 36%,71.9%and 53.9%respectively.A comparison of baseline characteristics between the two groups showed that patients with a non-dominant RCA were more likely to be men.For inferior wall ischemia on SPECT MPI,patients in study group 2 had a significantly higher PPV,32/42(76.1%),compared to patients in group 1,in which only 3 out of the 29 patients(10.3%)had true positive results(P value<0.001 Z test).The difference remained statistically significant even when only patients with left dominant coronary system(without co-dominant)were compared to patients with right dominant system(32/40,76.1%in right dominant group,3/19,15.8%in left dominant group,P value<0.001 Z test).There was no significant difference in mean hospital stay,re-hospitalization,and in-hospital mortality between the two groups.CONCLUSION The positive predictive value of SPECT MPI for inferior wall ischemia is affected by coronary artery dominance.More studies are needed to explain this phenomenon.

Current dilemma in photocatalytic CO_(2) reduction:real solar fuel production or false positive outcomings?

Solar driven carbon dioxide(CO_(2))recycling into hydrocarbon fuels using semiconductor photocatalysts offers an ideal energy conversion pathway to solve both the energy crisis and environmental degradation problems.However,the ubiquitous presence of carbonaceous contaminants in photocatalytic CO_(2) reduction system and the inferior yields of hydrocarbon fuels raise serious concerns about the reliability of the reported experimental results.Here in this perspective,we focus on the accurate assessment of the CO_(2) reduction products,systemically discuss the possible sources of errors in the product quantification,elaborate the common mistakes spread in the analysis of reaction products obtained in 13CO_(2) labelling experiments,and further propose reliable protocols for reporting the results of these isotopic tracing experiments.Moreover,the challenges and cautions in the precise measurement of O_(2) evolution rate are also depicted,and the amplification of the concentration of O_(2) in photoreactors well above the limit of detection is still demonstrated to be the most effective solution to this troublesome issue.We hope the viewpoints raised in this paper will help to assessment the reliability of the reported data in future,and also benefit the beginners that intend to dive in the photocatalytic CO_(2) reduction area.