Mach Band Sign: An Optical Illusion

Panikkath, Ragesh; Panikkath, Deepa

doi:10.1080/08998280.2014.11929161

Cited by 8 publications

(4 citation statements)

References 2 publications

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“…This is not surprising, as various factors make diagnosing <1/2 width enamel caries difficult, such as the small surface area for analysis or Mach bands. 23 Alternative methods to BW examination for interproximal caries detection have been introduced. 24–27 Recent studies showed that performances of near-infrared light transillumination, fiber-optic trans-illumination, and laser fluorescence may be comparable to the radiographic examination.…”

Section: Discussionmentioning

confidence: 99%

Effects of healthcare policy and education on reading accuracy of bitewing radiographs for interproximal caries

Sato

Silva

Lee

et al. 2021

Dentomaxillofacial Radiology

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Objectives The aim of this study is to assess the accuracy of bitewing radiograph interpretation of predoctoral students, residents and general dentists who work under different core curriculum of dental education and healthcare policy. Methods A total of 118 examiners including predoctoral dental students, residents and general dentists from USA and Japan were tasked with evaluating a series of bitewing radiographs and diagnosing interproximal carious lesions. This study was approved by the Harvard Medical School Institutional Review Board (IRB). Participants graded interproximal aspects of those images and categorized the following criteria; “intact”, “enamel caries <1/2 width”, “enamel caries >1/2 width” or “caries into dentin”. The gold-standard was determined by the consensus of two HSDM full-time faculty. Results There was significant difference in the sensitivity for all three caries levels between the two groups but there was no significant difference on specificity. The positive-predictive and negative-predictive values of the USA group for the enamel caries (<1/2 of enamel) were significantly higher than the Japanese group. The average of AUC (ROC) was significantly higher in the USA group (0.885 ± 0.04) than the Japanese group (0.785 ± 0.08, p<0.01). Conclusion Teaching and adopting BW radiographs for diagnosis of interproximal caries is integral for dental providers to accurately and efficiently use them in their practices. It is critical that all dental educators approach policymakers to explain the importance of BW radiographs and promote their efficacy for prevention and early diagnosis of interproximal caries.

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Section: Discussionmentioning

confidence: 99%

Effects of healthcare policy and education on reading accuracy of bitewing radiographs for interproximal caries

Sato

Silva

Lee

et al. 2021

Dentomaxillofacial Radiology

View full text Add to dashboard Cite

show abstract

“…A dark halo may be seen around the mass on mammography known as the Mach effect which is an optical illusion caused by the inbuilt edge enhancement mechanism of human retina. (17) Involuting broadenomas particularly in postmenopausal females may show calcication. (18) Out of 58 cases, only 41 were diagnosed on MG, the rest of the mammograms were read as normal due to obscuration of the lesion by increased breast density.…”

Section: Discussionmentioning

confidence: 99%

Evaluating Symptomatic Breast Disease by Complementary Sonography as an Adjunct to Mammography: A Must

Kaur

Chhabra

Kaur³

2021

IJAR

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Objectives: To evaluate symptomatic breast disease by imaging and calculate sensitivity and specificity of mammography (MG) and ultrasound (USG) independently and using them as a combined modality. Materials and Methods: 352 patients presenting with symptomatic breast disease in the Out-Patient Department or admitted in the wards were included in our study. 193 patients underwent Fine needle aspiration cytology (FNAC) of the abnormality detected either on MG or USG and constituted the study population. Senstivity, specificity and Negative Predictive Value of MG, USG and MG+USG was calculated. Results: Out of 352 patients included in our study, the maximum number of patients (158) were between 31-40 years. Pain and palpable lump were the common complaints in our study group. The most common lesion was fibroadenoma present in 58 patients followed by fibrocystic breast disease in 52, abscess in 18, cysts in 12, and benign duct ectasia in 12 patients. Carcinoma was present in 41 patients and most were in the older age group. The senstivity of MG, USG, MG+USG in diagnosing breast disease was calculated to be 72.7%,90.9%, and 96.96% respectively and specificity of MG, USG, MG+USG was calculated to be 92.35%,89.28%,100% respectively. The negative predictive value (NPV) of MG was lower 74.28% whereas USG had NPV of 89.28%. A higher NPV of 96.55% was seen when MG and USG were used complementary to each other. Conclusion: Using MG and USG as complementary to each other increases the NPV and enhance the confidence of the radiologist in the detection and characterization of the lesion. Age-based criteria should be used to choose the type of diagnostic modality to be used for evaluating the breast.

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“…Thus, while the perceptual expertise of radiologists will not always prevent them from misperceiving images, prior knowledge and experience may improve diagnostic accuracy (Anbari and West, 1997). For example, in a case study reported by Panikkath and Panikkath (2014), Mach bands at the lateral margin of the right atrium were initially interpreted as evidence of pneumopericardium in a chest radiograph. Awareness that this might be a perceptual effect-and the discovery that other follow-up imaging did not show signs of air around the heart-revealed that this radiolucent shadow was in fact caused by Mach bands.…”

Section: Mach Bandsmentioning

confidence: 99%

Visual Illusions in Radiology: Untrue Perceptions in Medical Images and Their Implications for Diagnostic Accuracy

et al. 2021

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Errors in radiologic interpretation are largely the result of failures of perception. This remains true despite the increasing use of computer-aided detection and diagnosis. We surveyed the literature on visual illusions during the viewing of radiologic images. Misperception of anatomical structures is a potential cause of error that can lead to patient harm if disease is seen when none is present. However, visual illusions can also help enhance the ability of radiologists to detect and characterize abnormalities. Indeed, radiologists have learned to exploit certain perceptual biases in diagnostic findings and as training tools. We propose that further detailed study of radiologic illusions would help clarify the mechanisms underlying radiologic performance and provide additional heuristics to improve radiologist training and reduce medical error.

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Mach Band Sign: An Optical Illusion

Cited by 8 publications

References 2 publications

Effects of healthcare policy and education on reading accuracy of bitewing radiographs for interproximal caries

Effects of healthcare policy and education on reading accuracy of bitewing radiographs for interproximal caries

Evaluating Symptomatic Breast Disease by Complementary Sonography as an Adjunct to Mammography: A Must

Visual Illusions in Radiology: Untrue Perceptions in Medical Images and Their Implications for Diagnostic Accuracy

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