The potential value of a pictorial atlas for aid in the visual diagnosis of 123I FP-CIT SPECT scans

Comparing the effectiveness of two diagnostic approaches for the interpretation of oral radiographic lesions by dental students

Interpreting radiographic lesions on dental radiographs is a challenging process especially for novice learners, and there is a lack of tools available to support this diagnostic process. This study introduced dental students to two diagnostic aids with contrasting reasoning approaches-ORAD DDx, which uses an analytic, forward reasoning approach, and a Radiographic Atlas, which emphasizes a non-analytic, backward reasoning approach. We compared the effectiveness of ORAD DDx and the Atlas in improving students' diagnostic accuracy and their ability to recall features of radiographic lesions. Participants (99 third-year dental students) were assigned to ORAD DDx, Atlas and Control groups. In the pre-test and post-test, participants provided their diagnosis for eight types of radiographic lesions. All groups also completed a Cued Recall Test. Feedback about ORAD DDx and the Atlas was collected. Results indicated that the Atlas was more effective than ORAD DDx in improving diagnostic accuracy (Estimated marginal mean difference = 1.88 (95% CI 0.30-3.46), p = 0.014, Cohen's d = 0.714). Participants in the Atlas group also outperformed the Control group in the recall of the lesions' radiographic features (Estimated marginal mean difference = 3.42 (95% CI 0.85-5.99), p = 0.005, Cohen's d = 0.793). Students reported that both ORAD DDx and Atlas increased their confidence and decreased the mental effort required to develop differential diagnosis (p ≤ 0.001). This study demonstrates the effectiveness of a non-analytic approach in interpreting dental radiographs among novice learners through the novel use of diagnostic aids.

123I-FP-CIT SPECT imaging of the dopaminergic state

123I-N-ω-fluoropropyl-2β-carbomethoxy-3β- (4-iodophenyl)nortropan (123I-FP-CIT) single photon emission computed tomography (SPECT) can be evaluated by both visual assessment and quantitative analysis to assess the striatal dopamine state in vivo. The aim of our study was to investigate if visual assessment according to a predefined image grading scale reflects the results of quantitative assessment techniques. Patients, methods: 195 patients with a clinical diagnosis of idiopathic Parkinson's disease (n = 134), atypical parkinsonian syndrome (n = 47) or essential tremor (n = 14) were examined with 123I-FP-CIT SPECT and included in this retrospective study. Results were analysed according to predefined visual patterns of dopaminergic degeneration and graded as normal (grade 5) or abnormal (grade 1–4) independently by three raters. Quantitative two-dimensional (2D) operator-dependent, manual and three-dimensional (3D) operator- independent, automated approaches were used for quantitative analysis of the specific 123I-FP-CIT tracer binding ratio (SBR) for caudate and putamen. Results: Sensitivity, specificity, PPV, NPV and diagnostic accuracy of visual assessment of 123I-FP-CIT SPECT for the diagnosis of a neuro degenerative Parkinson's syndrome were 99%, 86%, 99%, 86% and 98%, respectively. Visual assessment and quantitative analysis agreed well in evaluating the degree of dopaminergic degeneration. Significant differences (p < 0.001) were found between degeneration patterns. Only between the so-called eagle wing degeneration and the normal pattern no significant differences in SBR caudate and putamen were found, neither by the quantitative manual (p = 1.00; p = 0.196) nor by the quantitative automated method (p = 1.0; p = 0.785). Inter-rater agreement for visual assessment was substantial for all possible pairs of the three raters (κ = 0.70 to 0.74). Strong correlations were observed between the quantitative manual and quantitative automated methods for quantification of SBR caudatum (r = 0.920, r2 = 0.846, p < 0.001) and SBR putamen (r = 0.908, r2 = 0.824, p < 0.001). Conclusion: Visual assessment was highly consistent with the results obtained by quantitative analysis and showed a substantial inter-rater agreement between experienced and inexperienced raters. Our findings indicate that visual assessment might be a reliable analysis approach for clinical routine.

Is ioflupane I123 injection diagnostically effective in patients with movement disorders and dementia? Pooled analysis of four clinical trials

OBJECTIVES

To pool clinical trials of similar design to assess overall sensitivity and specificity of ioflupane I123 injection (DaTSCAN or ioflupane ((123)I)) to detect or exclude a striatal dopaminergic deficit disorder (SDDD), such as parkinsonian syndrome and dementia with Lewy bodies.

DESIGN

Pooled analysis of three phase 3 and one phase 4 clinical trials. These four trials were selected because they were the four studies used for the US new drug application to the Food and Drug Administration (FDA).

SETTING

Multicentre, open-label, non-randomised.

PARTICIPANTS

Patients with either a movement disorder or dementia, and healthy volunteers.

INTERVENTIONS

Ioflupane ((123)I) was administered.

OUTCOME MEASURES

Images were assessed by panels of 3-5 blinded experts and/or on-site nuclear medicine physicians, classified as normal or abnormal and compared with clinical diagnosis (reference standard) to determine sensitivity and specificity.

RESULTS

Pooling the four studies, 928 participants were enrolled, 849 were dosed and 764 completed their study. Across all studies, when images were assessed by on-site readers, ioflupane ((123)I) diagnostic effectiveness had an overall (95% CI) sensitivity of 91.9% (88.7% to 94.5%) and specificity of 83.6% (78.7% to 87.9%). When reads were conducted blindly by a panel of independent experts, the overall sensitivity was 88.7% (86.8% to 90.4%) and specificity was 91.2% (89.0% to 93.0%).

CONCLUSIONS

In this pooled analysis, the visual assessment of ioflupane ((123)I) images provided high levels of sensitivity and specificity in detecting the presence/absence of an SDDD. Ioflupane ((123)I) imaging has the potential to improve diagnostic accuracy in patients with signs and symptoms of a movement disorder and/or dementia.

TRIAL REGISTRATION NUMBER

NCT00209456.

Visual assessment of dopaminergic degeneration pattern in 123I-FP-CIT SPECT differentiates patients with atypical parkinsonian syndromes and idiopathic Parkinson's disease

The aim of this study was to investigate whether visual assessment of (123)I-N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropan ((123)I-FP-CIT) single photon emission computed tomography (SPECT) in addition to quantitative analyses can help to differentiate idiopathic Parkinson's disease (PD) from atypical parkinsonian syndromes (APS). From a consecutive series of patients examined with (123)I-FP-CIT SPECT (n = 190) over a three-year period we identified 165 patients with a clinical diagnosis of PD (n = 120) or APS (n = 45). (123)I-FP-CIT SPECT results were analysed visually and quantitatively and compared for PD and APS and for the subgroup of patients with early PD and APS (disease duration <5 years). According to predefined visual patterns of dopaminergic degeneration the results were graded as normal (grade 5) or abnormal (grade 1-4), distinguishing a posterior-anterior degeneration pattern ("egg shape") from a global and severe degeneration pattern ("burst striatum"). Visual assessment of (123)I-FP-CIT SPECT showed significant different dopaminergic degeneration patterns for PD and APS patients. A grade 1 ("burst striatum") degeneration pattern was predominantly associated with APS patients. In contrast to that, a grade 2 (egg shape) degeneration pattern was the characteristic finding in PD patients. In a subgroup of patients with early disease, visual assessment with identification of the burst striatum degeneration pattern provided 90% positive predictive value and 99% specificity for the diagnosis of APS. Quantitative analysis of striatal binding ratios failed to depict these different degeneration patterns in PD and APS patients. Visual assessment of the pattern of dopaminergic loss in (123)I-FP-CIT SPECT shows different patterns of dopaminergic degeneration for PD and APS patients. Therefore, it could provide valuable information to distinguish APS from PD patients, especially in early stages of disease. Within the first 5 years of disease, the occurrence of a burst striatum degeneration pattern has a high positive predictive value of APS.