Browsing by Subject "Magnetic resonance"

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    Effects of pneumoperitoneum and body position on the morphology of the caudal cava vein analyzed by MRI and plastinated sections
    (Springer Nature, 2012-10-24) Párraga Ros, Ester; López Albors, Octavio Miguel; Sánchez-Margallo, Fco; Moyano-Cuevas, J.L.; Latorre Reviriego, Rafael Manuel; Anatomía y Anatomía Patológica Comparada
    Background Pneumoperitoneum and patient positioning are essential factors during laparoscopic surgical procedures. They cause hemodynamic and anatomical changes in several abdominal organs among which the caudal cava vein (CCV) is involved. Hemodynamic changes in this vein (decreased venous return) have been described in the porcine model, but how the vein morphology and size is affected at different abdominal levels is unknown. We sought to assess the morphological and morphometrical changes in the CCV of the pig caused by pneumoperitoneum and the reverse Trendelenburg position by in vivo magnetic resonance imaging (MRI). Methods Six pigs were scanned via MRI under four situations: S1, control (no pneumoperitoneum); S2, control in the reverse Trendelenburg position; S3, pneumoperitoneum (14 mmHg); and S4, pneumoperitoneum in the reverse Trendelenburg position. MRI and plastinated body sections were used to evaluate the topography, morphology and cross-sectional area of the CCV. Results Two portions of the CCV were differentiated: a prehepatic portion (located between the vertebral levels L1–T15) with flat and irregular morphology, and a hepatic portion (between T14–T11) that was almost rounded. The reverse Trendelenburg position caused an increase in the lumen affecting mainly the prehepatic portion, while pneumoperitoneum caused a decrease in the total vascular lumen, exerting a greater effect on the hepatic portion. The combination of both situations resulted in a further decrease in the vascular area and global morphological changes. Conclusions The pneumoperitoneum and reverse Trendelenburg position caused morphological and morphometrical changes in the prehepatic and hepatic portions of the CCV, which should assist in gaining a better understanding of the hemodynamic changes described in the literature.
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    Grading lung neuroendocrine tumors: Controversies in search of a solution
    (Universidad de Murcia. Departamento de Biología Celular e Histología, 2017) Pelosi, Giuseppe; Pattini, Linda; Morana, Giovanni; Fabbri, Alessandra; Faccinetto, Alex; Fazio, Nicola; Valeri, Barbara; Sonzogni, Angelica
    Background. Pathological grading of tumors is a way to measure biological aggressiveness. In lung neuroendocrine tumors (NET), grading is tautologically included into the current 2015 WHO histologic classification. Little is known, however, about alternative grading systems in lung NET. Methods. Through an extensive search of the English literature on lung NET (updated to April 2016), the following key questions were addressed: a) current concepts of grading; b) clinicians’ requests for grading; c) functional parameters for grading; d) Ki-67 labeling index (LI) for grading; e) towards an effective pathology grading system. Results. There is some room for inconsistency in the histologic classification of lung NET, likely due to the varying attribution of defining criteria. Innovative diffusion-weighted imaging upon magnetic resonance or molecular analysis could help separate indolent from aggressive lung NET, thus integrating a grading approach other than histology. Troubles in the clinical handling of metastatic or individual tumors when relying on morphology alone support the development of a lungspecific grading system for the more accurate prediction of prognosis and planning therapy in individual patients. To integrate the 2015 WHO classification using innovative grading based on Ki-67 LI, mitotic count and necrosis, a new proposal is emerging where three categories of lung NET are identified, namely Lu-NET G1, Lu-NET G2 and Lu-NET G3, which would allow tumors with similar behavior and therapy to be better handled according to their own biological potential. Conclusion. A new formulation of lung NET grading could have clinical relevance for the individual handling of patients. Key words: