Threshold analysis using diagnostic tests with multiple results

Trends in non-focal neurological chief complaints and CT angiography utilization among adults in the emergency department

Prudent imaging use is essential for cost reduction and efficient patient triage. Recent efforts have focused on head and neck CTA in patients with emergent concerns for non-focal neurological complaints, but have failed to demonstrate whether increases in utilization have resulted in better care. The objective of this study was to examine trends in head and neck CTA ordering and determine whether a correlation exists between imaging utilization and positivity rates. This is a single-center retrospective observational study at a quaternary referral center. This study includes patients presenting with headache and/or dizziness to the emergency department between January 2017 and December 2021. Patients who received a head and neck CTA were compared to those who did not. The main outcomes included annual head and neck CTA utilization and positivity rates, defined as the percent of scans with attributable acute pathologies. Among 24,892 emergency department visits, 2264 (9.1%) underwent head and neck CTA imaging. The percentage of patients who received a scan over the study period increased from 7.89% (422/5351) in 2017 to 13.24% (662/5001) in 2021, representing a 67.4% increase from baseline (OR, 1.14; 95% CI 1.11-1.18; P < .001). The positivity rate, or the percentage of scans ordered that revealed attributable acute pathology, dropped from 16.8% (71/422) in 2017 to 10.4% (69/662) in 2021 (OR, 0.86; 95% CI 0.79-0.94; P = .001), a 38% reduction in positive examinations. Throughout the study period, there was a 67.4% increase in head and neck CTA ordering with a concomitant 38.1% decrease in positivity rate.

Effectiveness of the clinical decision support tool ESR eGUIDE for teaching medical students the appropriate selection of imaging tests: randomized cross-over evaluation

OBJECTIVES

To evaluate ESR eGUIDE-the European Society of Radiology (ESR) e-Learning tool for appropriate use of diagnostic imaging modalities-for learning purposes in different clinical scenarios.

METHODS

This anonymized evaluation was performed after approval of ESR Education on Demand leadership. Forty clinical scenarios were developed in which at least one imaging modality was clinically most appropriate, and the scenarios were divided into sets 1 and 2. These sets were provided to medical students randomly assigned to group A or B to select the most appropriate imaging test for each scenario. Statistical comparisons were made within and across groups.

RESULTS

Overall, 40 medical students participated, and 31 medical students (78%) answered both sets. The number of correctly chosen imaging methods per set in these 31 paired samples was significantly higher when answered with versus without use of ESR eGUIDE (13.7 ± 2.6 questions vs. 12.1 ± 3.2, p = 0.012). Among the students in group A, who first answered set 1 without ESR eGUIDE (11.1 ± 3.2), there was significant improvement when set 2 was answered with ESR eGUIDE (14.3 ± 2.5, p = 0.013). The number of correct answers in group B did not drop when set 2 was answered without ESR eGUIDE (12.4 ± 2.6) after having answered set 1 first with ESR eGUIDE (13.0 ± 2.7, p = 0.66).

CONCLUSION

The clinical decision support tool ESR eGUIDE is suitable for training medical students in choosing the best radiological imaging modality in typical scenarios, and its use in teaching radiology can thus be recommended.

KEY POINTS

• ESR eGUIDE improved the number of appropriately selected imaging modalities among medical students. • This improvement was also seen in the group of students which first selected imaging tests without ESR eGUIDE. • In the student group which used ESR eGUIDE first, appropriate selection remained stable even without the teaching tool.

Should malaria treatment be guided by a point of care rapid test? A threshold approach to malaria management in rural Burkina Faso

BACKGROUND

In Burkina Faso, rapid diagnostic tests for malaria have been made recently available. Previously, malaria was managed clinically. This study aims at assessing which is the best management option of a febrile patient in a hyperendemic setting. Three alternatives are: treating presumptively, testing, or refraining from both test and treatment. The test threshold is the tradeoff between refraining and testing, the test-treatment threshold is the tradeoff between testing and treating. Only if the disease probability lies between the two should the test be used.

METHODS AND FINDINGS

Data for this analysis was obtained from previous studies on malaria rapid tests, involving 5220 patients. The thresholds were calculated, based on disease risk, treatment risk and cost, test accuracy and cost. The thresholds were then matched against the disease probability. For a febrile child under 5 in the dry season, the pre-test probability of clinical malaria (3.2%), was just above the test/treatment threshold. In the rainy season, that probability was 63%, largely above the test/treatment threshold. For febrile children >5 years and adults in the dry season, the probability was 1.7%, below the test threshold, while in the rainy season it was higher (25.1%), and situated between the two thresholds (3% and 60.9%), only if costs were not considered. If they were, neither testing nor treating with artemisinin combination treatments (ACT) would be recommended.

CONCLUSIONS

A febrile child under 5 should be treated presumptively. In the dry season, the probability of clinical malaria in adults is so low, that neither testing nor treating with any regimen should be recommended. In the rainy season, if costs are considered, a febrile adult should not be tested, nor treated with ACT, but a possible alternative would be a presumptive treatment with amodiaquine plus sulfadoxine-pyrimethamine. If costs were not considered, testing would be recommended.

Pulmonary embolism: making sense of the diagnostic evaluation

Despite the publication of the Prospective Investigation of Pulmonary Embolism Diagnosis in 1990, the diagnostic evaluation of pulmonary embolism continues to be approached in an inconsistent fashion. The reasons for this are unclear but likely have to do with inadequate methods for predicting pretest probability of disease and the inconvenience and perceived risk of pulmonary angiography. Because pulmonary embolism and its treatment carry substantial risk of morbidity and mortality, a consistent approach to evaluation is desirable. This article reviews large, prospective studies that suggest that it may be unnecessary to diagnose pulmonary embolism with the certainty that pulmonary angiography allows. Finally, the article proposes an algorithm that may be acceptable to patients and clinicians alike if safety is confirmed in future prospective studies.

Central nervous system involvement in systemic lupus erythematosus: cerebral imaging and serological profile in patients with and without overt neuropsychiatric manifestations

The aim of this study was to evaluate morphological and functional abnormalities by cerebral imaging in a series of systemic lupus erythematosus (SLE) patients with and without overt central nervous system (CNS) manifestations, and to detect possible relationships with clinical parameters and a large panel of autoantibodies, including those reactive against neurotypic and gliotypic antigens. 68 patients with SLE were investigated in a cross-sectional study which included clinical evaluation of symptoms, cerebral magnetic resonance imaging (MRI) and brain single photon emission tomography (SPECT) analysis, electroencephalography (EEG), and serological tests for antibodies directed against nuclear, cytoplasmic neuronal and glial cell-related antigens. The results of this study showed: (1) a significant positive association of (a) anti-glial fibrillary acidic protein (GFAP) serum antibodies with neuropsychiatric (NP) manifestations and (b) anti-serin proteinase 3 (anti-PR3/c-ANCA) serum antibodies with pathological cerebral SPECT; (2) the presence of significantly higher values of (a) SLICC organ damage index in patients with abnormal MRI and (b) SLAM activity index in patients with abnormal SPECT; and (3) the association of (a) abnormal MRI with nonactive NP manifestations and (b) combined abnormality of brain SPECT and MRI with the occurrence of overall overt NP manifestations and with those of the organic/major type. Neuropsychiatric manifestations, namely those of the organic/major type, appeared to be significantly associated to the presence of a serum antibody against GFAP, a gliotypic antigen. There was also evidence of an association between SPECT abnormality and the presence of anti-PR3 (c-ANCA). Furthermore, brain imaging by MRI and SPECT applied to SLE patients appears to express CNS involvement significantly related to specific categories of NP manifestations. The abnormalities detected by the two tests seem to be preferentially associated with different activity phases of the NP disorder or of the lupus disease.

Autoantibodies in neurodegenerative diseases: antigen-specific frequencies and intrathecal analysis

The frequency of autoantibodies (AAbs) was surveyed in several neurodegenerative diseases, other neurological diseases, and controls using antigen-specific EIAs for neurofilament heavy subunit, tubulin, glial fibrillary acidic protein, S100 protein, tau, beta-amyloid peptide, myelin basic protein, and heparan sulfate proteoglycan. High frequencies of sera and cerebrospinal fluid tubulin AAbs were found in Alzheimer disease (62% and 69%, respectively), Parkinson disease (27% and 70%), amyotrophic lateral sclerosis (54% and 67%), and in sera from multiple sclerosis (50% and 67%), optic neuritis (85%), Guillain-Barré syndrome (88%), and vascular dementia (52%). High frequencies of neurofilament heavy subunit AAbs were detected in Guillain-Barré syndrome, chronic peripheral neuropathy (88%) and optic neuritis (62%); whereas, some Alzheimer's disease (33%) and vascular dementia (44%) patients had glial fibrillary acidic protein AAbs. Lower frequencies of other AAbs were found in patient groups. AAb results were also compared to functional assessment of blood-brain barrier integrity in Parkinson's disease and Alzheimer's disease. The relevance of these AAbs to pathogenesis and/or course of neurologic diseases merits further study with particular reference to subgrouping and prognosis.

Work-up of patients with malignancy after an intermediate-probability ventilation-perfusion scan: why don't physicians pursue a definitive diagnosis?

RATIONALE AND OBJECTIVES

The authors determined whether there are specific patient characteristics associated with the clinical decision to eschew further diagnostic testing in patients in whom a ventilation-perfusion (V-P) scan indicates intermediate probability of pulmonary embolism (PE).

MATERIALS AND METHODS

The authors reviewed all intermediate-probability V-P scans obtained in a 12-month period. Patients were divided into two groups. Group 1 comprised patients in whom a definitive diagnosis of PE was not obtained and who were not treated for PE (n = 57); group 2 comprised patients in whom the diagnosis of PE was confirmed or excluded and who, if PE was confirmed, received appropriate treatment (n = 14). Age, gender, frequency of malignancy, and survival of patients in groups 1 and 2 were compared.

RESULTS

The frequency of malignancy was significantly greater in group 1 than in group 2 (P = .012). Although the estimated 2-year survival of group 1 patients was significantly less than that of group 2 patients (P = .039), this difference is likely due to confounding by age and malignancy.

CONCLUSION

When an intermediate-probability V-P scan is obtained, physicians are significantly less likely to pursue a definitive diagnosis of PE in patients with malignancy.

Decision-making studies in patient management: twenty years later

This article surveys the contribution of decision analysis to diagnosis and treatment in medicine, beginning with a review of Dr. Lee B. Lusted's 1971 paper, "Decision-making studies in patient management." From this beginning methods of decision analysis were developed that were particularly appropriate to medical problems. The author reviews the effects of Dr. Lusted's interests in the field on subsequent research and publications, and critiques prophetic statements found in the early paper.