The Impact of Multifocal Intraocular Lens in Retinal Imaging with Optical Coherence Tomography

Multifocal intraocular lenses (MF IOLs) have concentric optical zones with different dioptric power, enabling patients to have good visual acuity at multiple focal points. However, several optical limitations have been attributed to this particular design. The purpose of this study is to access the effect of MF IOLs design on the accuracy of retinal optical coherence tomography (OCT). Cross-sectional study conducted at the Refractive Surgery Department of Central Lisbon Hospital Center. Twenty-three eyes of 15 patients with a diffractive MF IOL and 27 eyes of 15 patients with an aspheric monofocal IOL were included in this study. All patients underwent OCT macular scans using Heidelberg Spectralis®. Macular thickness and volume values and image quality (Q factor) were compared between the two groups. There were no statistically significant differences between both groups regarding macular thickness or volume measurements. Retinal OCT image quality was significantly lower in the MF IOL group (p < 0.01). MF IOLs are associated with a significant decrease in OCT image quality. However, this fact does not seem to compromise the accuracy of spectral domain OCT retinal measurements.

Prostate Cancer: The Role of Multiparametric Magnetic Resonance Imaging

Multiparametric Magnetic Resonance Imaging has been increasingly used for detection, localization and staging of prostate cancer over the last years. It combines high-resolution T2 Weighted-Imaging and at least two functional techniques, which include Dynamic Contrast–Enhanced Magnetic Resonance Imaging, Diffusion-Weighted Imaging, and Magnetic Resonance Imaging Spectroscopy. Although the combined use of a pelvic phased-array and an Endorectal Coil is considered the state-of-the-art for Magnetic Resonance Imaging evaluation of prostate cancer, Endorectal Coil is only absolute mandatory for Magnetic Resonance Imaging Spectroscopy at 1.5 T. Sensitivity and specificity levels in cancer detection and localization have been improving with functional technique implementation, compared to T2 Weighted-Imaging alone. It has been particularly useful to evaluate patients with abnormal PSA and negative biopsy. Moreover, the information added by the functional techniques may correlate to cancer aggressiveness and therefore be useful to select patients for focal radiotherapy, prostate sparing surgery, focal ablative therapy and active surveillance. However, more studies are needed to compare the functional techniques and understand the advantages and disadvantages of each one. This article reviews the basic principles of prostatic mp-Magnetic Resonance Imaging, emphasizing its role on detection, staging and active surveillance of prostate cancer.

Imaging the Hypoglossal Nerve

The hypoglossal nerve is a pure motor nerve. It provides motor control to the intrinsic and extrinsic tongue muscles thus being essential for normal tongue movement and coordination. In order to design a useful imaging approach and a working differential diagnosis in cases of hypoglossal nerve damage one has to have a good knowledge of the normal anatomy of the nerve trunk and its main branches. A successful imaging evaluation to hypoglossal diseases always requires high resolution studies due to the small size of the structures being studied. MRI is the preferred modality to directly visualize the nerve, while CT is superior in displaying the bony anatomy of the neurovascular foramina of the skull base. Also, while CT is only able to detect nerve pathology by indirect signs, such as bony expansion of the hypoglossal canal, MRI is able to visualize directly the causative pathological process as in the case of small tumors, or infectious/inflammatory processes affecting the nerve. The easiest way to approach the study of the hypoglossal nerve is to divide it in its main segments: intra-axial, cisternal, skull base and extracranial segment, tailoring the imaging technique to each anatomical area while bearing in mind the main disease entities affecting each segment.

Post-Treated Prostate Cancer: Normal Findings and Signs of Local Relapse on Multiparametric Magnetic Resonance Imaging

The use of multiparametric magnetic resonance imaging (mp-MRI) for prostate cancer has increased over recent years, mainly for detection, staging, and active surveillance. However, suspicion of recurrence in the set of biochemical failure is becoming a significant reason for clinicians to request mp-MRI. Radiologists should be able to recognize the normal post-treatment MRI findings. Fibrosis and atrophic remnant seminal vesicles after prostatectomy are often found and must be differentiated from local relapse. Moreover, brachytherapy, external beam radiotherapy, cryosurgery, and hormonal therapy tend to diffusely decrease the signal intensity of the peripheral zone on T2-weighted images (T2WI) due to the loss of water content, consequently mimicking tumor and hemorrhage. The combination of T2WI and functional studies like diffusion-weighted imaging and dynamic contrast-enhanced improves the identification of local relapse. Tumor recurrence tends to restrict on diffusion images and avidly enhances after contrast administration either within or outside the gland. The authors provide a pictorial review of the normal findings and the signs of local tumor relapse after radical prostatectomy, external beam radiotherapy, brachytherapy, cryosurgery, and hormonal therapy.

Esquistossomose pulmonar. I. Forma crônica extensa sem hipertensão pulmonar e na ausência de hipertensão portal

Com o objetivo de demonstrar algumas modalidades distintas do comprometimento pulmonar na esquistossomose mansoni, ressaltando sempre a diversidade dé interação dos múltiplos fatores envolvidos, os Autores iniciam a publicação de uma seqüência de casos ilustrativos, embora considerados pouco comuns na clínica diária. No caso ora descrito, ao lado de sintomatologia definida dominantemente por surtos paroxísticos de asma, o estudo radiológico seriado, durante sete anos, revelou imagem pieuro-parenquimatosa caracterizada por irregularidades de radiopacidade com traves fibróticas extensas, notadamente à direita e desvio acentuado do mediastino para este lado; a área cardíaca encontrava-se aparentemente normal. À microtoracotomia, observou-se lesão pleural dominante com enclausuramento do LSD e condensação extensa subpleural do LSD, afetando amplamente o parênquima. Procedeu-se àdetorticação do LM e LID e reexpansão parcial de seus parénquimas, bem como à biopsia pulmonar. Apesar de o estudo histopatológico haver revelado uma arterite pulmonar grave, não foram registrados sinais e sintomas de cor pulmonale. Este comprometimento pulmonar verificou-se, entretanto, isoladamente de uma forma hepato-esplênica e, conseqüentemente, na ausência de síndrome de hipertensão portai a determinar a rota oreferencial de migração de ovos e, eventualmente, de vermes aos pulmões.

Esquistossomose pulmonar. III. Forma crônica extensa com hipertensão pulmonar e na vigência de hipertensão portal associada a provável coroidite e retinite esquistossomótica

Os Autores descrevem um caso grave de esquistossomose mansoni numa criança de 9 anos de idade (forma hepática com hipertensão portai associada a forma pulmonar com hipertensão pulmonar e cor pulmonale) clinicamente caracterizado por episódios de insuficiência respiratória desencadeados em face de esforços físicos moderados. Sucessivos exames radiológicos de tórax revelaram comprometimento predominantemente arteriolar ao iado de uma micronodulação delicada e difusamente distribuída e configuração de cor pulmonale. Ao contrário do caso anteriormente descrito, a evolução se deu sem que se verificassem manifestações febris. Embora tenham sido afastadas várias hipóteses de associação da esquistossomose a concausas infectuosas, optou-se pelo tratamento de prova da tuberculose pulmonar. O fundo de olho também apresentava vários nódulos esbranquiçados disseminados pelo coróide e retina, caracterizando provável coroidite e retinite esquistossomótica. O tratamento antituberculoso resultou praticamente nulo. Não se procedeu ao tratamento específico da esquistossomose, considerando-se o alto risco da cardiopatia face aos esquistossomicidas disponíveis. A alta foi fornecida após treze meses de observação hospitalar. Não compareceu a ulterior controle.

The impact of online brand community on electronic word-of-mouth communications

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Portal do município

Trabalho de Projeto apresentado para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Novos Media e Práticas Web

Geospatial assessment of pest-induced forest damage through the use of UAV-bases NIR imaging and Gi-technology

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

Microwave imaging of the axilla to aid breast cancer diagnosis

Breast cancer is the most common type of cancer among women all over the world. An important issue that is not commonly addressed in breast cancer imaging literature is the importance of imaging the underarm region—where up to 80% of breast cancer cells can metastasise to. The first axillary lymph nodes to receive drainage from the primary tumour in the breast are called Sentinel Node. If cancer cells are found in the Sentinel Node, there is an increased risk of metastatic breast cancer which makes this evaluation crucial to decide what follow-up exams and therapy to follow. However, non-invasive detection of cancer cells in the lymph nodes is often inconclusive, leading to the surgical removal of too many nodes which causes adverse side-effects for patients. Microwave Imaging is one of the most promising non-invasive imaging modalities for breast cancer early screening and monitoring. This novel study tests the feasibility of imaging the axilla region by means of the simulation of an Ultra-Wideband Microwave Imaging system. Simulations of such system are completed in several 2D underarm models that mimic the axilla. Initial imaging results are obtained by means of processing the simulated backscattered signals by eliminating artefacts caused by the skin and beamforming the processed signals in order to time-align all the signals recorded at each antenna. In this dissertation several image formation algorithms are implemented and compared by visual inspection of the resulting images and through a range of performance metrics, such as Signal-to-Clutter Ratio and FullWidth Half Maximum calculations. The results in this study showed that Microwave Imaging is a promising technique that might allow to identify the presence and location of metastasised cancer cells in axillary lymph nodes, enabling the non-invasive evaluation of breast cancer staging.