Automatic Small Bowel Tumor Diagnosis by Using Multi-Scale Wavelet-Based Analysis in Wireless Capsule Endoscopy Images

BACKGROUND: Wireless capsule endoscopy has been introduced as an innovative, non-invasive diagnostic technique for evaluation of the gastrointestinal tract, reaching places where conventional endoscopy is unable to. However, the output of this technique is an 8 hours video, whose analysis by the expert physician is very time consuming. Thus, a computer assisted diagnosis tool to help the physicians to evaluate CE exams faster and more accurately is an important technical challenge and an excellent economical opportunity. METHOD: The set of features proposed in this paper to code textural information is based on statistical modeling of second order textural measures extracted from co-occurrence matrices. To cope with both joint and marginal non-Gaussianity of second order textural measures, higher order moments are used. These statistical moments are taken from the two-dimensional color-scale feature space, where two different scales are considered. Second and higher order moments of textural measures are computed from the co-occurrence matrices computed from images synthesized by the inverse wavelet transform of the wavelet transform containing only the selected scales for the three color channels. The dimensionality of the data is reduced by using Principal Component Analysis. RESULTS: The proposed textural features are then used as the input of a classifier based on artificial neural networks. Classification performances of 93.1% specificity and 93.9% sensitivity are achieved on real data. These promising results open the path towards a deeper study regarding the applicability of this algorithm in computer aided diagnosis systems to assist physicians in their clinical practice.

Neuroendocrine Tumours of the Female Genital Tract: a Case-Based Imaging Review with Pathological Correlation

BACKGROUND: Both primary and secondary gynaecological neuroendocrine (NE) tumours are uncommon, and the literature is scarce concerning their imaging features. METHODS: This article reviews the epidemiological, clinical and imaging features with pathological correlation of gynaecological NE tumours. RESULTS: The clinical features of gynaecological NE tumours are non-specific and depend on the organ of origin and on the extension and aggressiveness of the disease. The imaging approach to these tumours is similar to that for other histological types and the Revised International Federation of Gynecology and Obstetrics (FIGO) Staging System also applies to NE tumours. Neuroendocrine tumours were recently divided into two groups: poorly differentiated neuroendocrine carcinomas (NECs) and well-differentiated neuroendocrine tumours (NETs). NECs include small cell carcinoma and large cell neuroendocrine carcinoma, while NETs account for typical and atypical carcinoids. Cervical small cell carcinoma and ovarian carcinoid are the most common gynaecological NE tumours. The former typically behaves aggressively; the latter usually behaves in a benign fashion and tends to be confined to the organ. CONCLUSION: While dealing with ovarian carcinoids, extra-ovarian extension, bilaterality and multinodularity raise the suspicion of metastatic disease. NE tumours of the endometrium and other gynaecological locations are very rare. TEACHING POINTS: • Primary or secondary neurondocrine (NE) tumours of the female genital tract are rare. • Cervical small cell carcinoma and ovarian carcinoids are the most common gynaecological NE tumours. • Cervical small cell carcinomas usually behave aggressively. • Ovarian carcinoids tend to behave in a benign fashion. • The imaging approach to gynaecological NE tumours and other histological types is similar.

Melanoma and Satellite Blue Papule

The colors that are seen in dermoscopy depend on the anatomic level of the skin at which the chromophores are seen. Blue color can be found in a variety of melanocytic and nonmelanocytic lesions. An 89-year-old man presented with a 3-year history of a slow-growing, hyperpigmented patch located on the distal third of the right arm. Dermoscopy showed an atypical network, irregularly distributed globules, pigmented internal streaks and a milky-red area. Based on these findings a diagnosis of slow-growing malignant melanoma was made. Simultaneously, a well-defined blue papule was seen on the proximal third of the same arm. Dermoscopy disclosed a homogeneous blue pattern. After clinical and dermoscopic correlation our differential diagnosis for this blue lesion included cutaneous melanoma metastasis, blue nevus and foreign body reaction. The patient recalled its onset 75 years ago after a grenade explosion. We also discuss the blue lesion appearance under reflectance confocal microscopy and high-definition optical coherence tomography. Histopathological examination after excision of the hyperpigmented patch and blue papule revealed a melanoma in situ and a foreign body reaction, respectively. The diagnostic evaluation of a blue lesion should always rely on the integration of all data, especially clinical and dermoscopic features. Other non-invasive techniques, like reflectance confocal microscopy and high-definition optical coherence tomography can also be important aids for its differential diagnosis.