RESUMEN
Extracting automatically the complex set of features composing real high-dimensional data is crucial for achieving high performance in machine-learning tasks. Restricted Boltzmann machines (RBM) are empirically known to be efficient for this purpose, and to be able to generate distributed and graded representations of the data. We characterize the structural conditions (sparsity of the weights, low effective temperature, nonlinearities in the activation functions of hidden units, and adaptation of fields maintaining the activity in the visible layer) allowing RBM to operate in such a compositional phase. Evidence is provided by the replica analysis of an adequate statistical ensemble of random RBMs and by RBM trained on the handwritten digits data set MNIST.
RESUMEN
Digestive haemorrhage following supramesocolic abdominal surgery (cephalic duodenopancreatectomy, cholecystectomy, total oesogastrectomy) is a rare but serious complication, which can be life-threatening. Improvement in scanning techniques has made it possible to modify the diagnostic strategy and improve the therapeutic management of the patients. The aim of this iconographic review is to recall the causes of digestive haemorrhage following supramesocolic surgery and to illustrate the dominant role of tomodensitometry in diagnosing it and in planning and controlling the efficacy of endovascular treatment.
Asunto(s)
Endoscopía Gastrointestinal , Hemorragia Gastrointestinal/diagnóstico por imagen , Hemorragia Gastrointestinal/terapia , Aumento de la Imagen/métodos , Procesamiento de Imagen Asistido por Computador , Tomografía Computarizada Multidetector , Complicaciones Posoperatorias/diagnóstico por imagen , Complicaciones Posoperatorias/terapia , Adenocarcinoma/diagnóstico por imagen , Adenocarcinoma/cirugía , Adulto , Anciano , Anciano de 80 o más Años , Aneurisma Falso/diagnóstico por imagen , Aneurisma Falso/terapia , Aneurisma Roto/diagnóstico por imagen , Aneurisma Roto/terapia , Angiografía , Aortografía , Colecistectomía , Embolización Terapéutica , Esofagectomía , Extravasación de Materiales Terapéuticos y Diagnósticos/diagnóstico por imagen , Extravasación de Materiales Terapéuticos y Diagnósticos/terapia , Femenino , Gastrectomía , Hemorragia Gastrointestinal/etiología , Hemobilia/diagnóstico por imagen , Hemobilia/etiología , Hemobilia/terapia , Arteria Hepática/diagnóstico por imagen , Humanos , Masculino , Mesocolon/cirugía , Persona de Mediana Edad , Neoplasias Pancreáticas/diagnóstico por imagen , Neoplasias Pancreáticas/cirugía , Pancreaticoduodenectomía , Pancreatitis Crónica/diagnóstico por imagen , Pancreatitis Crónica/terapia , Complicaciones Posoperatorias/etiología , Arteria Esplénica/diagnóstico por imagen , StentsRESUMEN
Cystic lesions of the pancreas, with an estimated prevalence of 20%, frequently are incidental findings at imaging on asymptomatic patients. Pseudocysts, typically in a setting of pancreatitis, should first be excluded. Characterization of cystic tumors is more complicated. Still, it is important to differentiate between benign and malignant lesions. Multi-detector row CT and MRI allow characterization of such lesions in over 75% of cases. Indeterminate lesions should undergo endoscopic US with biopsy/aspiration and fluid analysis, especially for mucin producing tumors (rounded with thick enhancing wall). When imaging fails to fully characterize a lesion, follow-up may be proposed for lesions less than 3 cm in size, that are either unilocular with thin nonenhancing wall (simple cyst) or lobulated multilocular with thin nonenhancing wall (serous cystadenoma, isolated side branch IPMTP). Follow-up imaging shows that these tumors usually show very little change over time. Management is based on comparing estimated patient survival without treatment to surgical risks (morbidity, mortality, functional sequelae from the procedure).
Asunto(s)
Diagnóstico por Imagen , Hallazgos Incidentales , Quiste Pancreático/diagnóstico , Diagnóstico Diferencial , Humanos , Neoplasias Pancreáticas/diagnóstico , Seudoquiste Pancreático/diagnóstico , Pancreatitis/diagnósticoRESUMEN
PURPOSE: The quality of magnetic resonance cholangiopancreatography (MRCP) images is frequently degraded by high signal from the gastrointestinal tract on heavily T2W images. The purpose of this study is to evaluate pineapple juice (PJ) as an oral negative contrast agent in MRCP. MATERIALS AND METHODS: Results from MRCP in 50 patients with PJ and 50 patients with paramagnetic contrast (ferumoxsil-Lumirem) were compared. Reviewers were blinded to the type of contrast agent. Exam quality was recorded with regards to signal suppression in the stomach, duodenum and proximal small bowel and with regards to pancreatic duct and biliary ducts visualization. In vitro, the signal characteristics of several commercially available brands of PJ were assessed using T1W, T2W and MRCP sequences. Signal intensity was correlated with the manganese concentration measured using atomic absorption spectrometry. Finally, the reviewers compared the taste of PJ and ferumoxsil. RESULTS: On MRCP sequences, results were similar with regards to signal suppression in the stomach, duodenum and proximal small bowel with PJ and ferumoxsil. Visualization of the pancreatic duct, intrahgepatic bile ducts and CBD was similar with PJ and ferumoxsil. The signal intensity of commercially available brands of PJ on T2W and MRCP sequences correlated well with the measured manganese concentration on spectroscopy. Variations in manganese concentration were observed, with values ranging from 3.65 to 27.24 mg/L. The reviewers noted that PJ tasted "good" or "very good" and that ferumoxsil tasted "bad" or "very bad". CONCLUSION: Ingestion of PJ provides effective signal suppression in the GI tract on MRCP, similar to paramagnetic contrast agents. Because manganese concentration is highly variable in commercially available PJ brands, a brand with high manganese concentration should be selected.
Asunto(s)
Ananas , Bebidas , Pancreatocolangiografía por Resonancia Magnética/métodos , Medios de Contraste , Hierro , Óxidos , Siloxanos , Administración Oral , Distribución de Chi-Cuadrado , Medios de Contraste/administración & dosificación , Óxido Ferrosoférrico , Humanos , Procesamiento de Imagen Asistido por Computador , Imagenología Tridimensional , Nanopartículas de Magnetita , Manganeso/análisis , Espectrofotometría Atómica , GustoRESUMEN
OBJECTIVE: The abdominal and retroperitoneal lymphatic system is characterized by numerous anatomic variations. Our objective is to review MR lymphographic features of normal anatomy and abnormal conditions. CONCLUSION: MR lymphography is a noninvasive technique that is well suited for the examination of abdominal and retroperitoneal lymphatic vessels.
Asunto(s)
Abdomen/patología , Enfermedades Linfáticas/diagnóstico , Vasos Linfáticos/patología , Imagen por Resonancia Magnética/métodos , Espacio Retroperitoneal/patología , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Guías de Práctica Clínica como Asunto , Pautas de la Práctica en MedicinaRESUMEN
The imaging features of infectious and non-infectious pathologies in HIV patients with AIDS (less than 200 CD4/mm3) are illustrated. Opportunistic infections, tumors and vascular pathologies have variable appearances based on the degree of immunosuppression and patient compliance with opportunistic infection prophylaxis. Because of advances in retroviral treatments and wider use of anti-infectious prophylaxis, thoracic pathologies in AIDS patients are less frequent but must nonetheless be recognized, and diagnosis should be suggested in patients with unknown serologic status.
Asunto(s)
Síndrome de Inmunodeficiencia Adquirida/complicaciones , Enfermedades Pulmonares/diagnóstico , Tomografía Computarizada por Rayos X , Infecciones Oportunistas Relacionadas con el SIDA/diagnóstico , Adulto , Aspergilosis/diagnóstico , Criptococosis/diagnóstico , Histoplasmosis/diagnóstico , Humanos , Hipertensión Pulmonar/diagnóstico , Enfermedades Pulmonares Fúngicas/diagnóstico , Enfermedades Pulmonares Intersticiales/diagnóstico , Neoplasias Pulmonares/diagnóstico , Linfoma/diagnóstico , Trastornos Linfoproliferativos/diagnóstico , Persona de Mediana Edad , Neumonía por Pneumocystis/diagnóstico , Sarcoma de Kaposi/diagnóstico , Tuberculosis Pulmonar/diagnósticoRESUMEN
Solitary fibrous tumor (SFT) is commonly found on serosal surfaces, and is rarely localized in the liver. There are benign and malignant variants of hepatic SFT. We report a new case of benign SFT. Our patient, a 63-year old woman, who has been followed for 5 years for an asymptomatic liver mass, was admitted for abdominal pain. Ultrasonography (US), CT, MR Imaging and angiography showed the liver mass with typical imaging features, situated in the right hepatic lobe with blood supply from the hepatic artery. Histopathological examination demonstrated a highly vascularized tumor, composed of short spindle cells alternating with hypocellular collagenous regions, with a hemangiopericytoma-like vascular pattern. The immunohistochemical staining was positive for CD 34. Tumor resection was performed. Follow-up 8 years after the resection showed no tumor recurrence or metastasis, thus confirming the initial diagnosis of benign SFT.
Asunto(s)
Neoplasias Hepáticas/diagnóstico , Neoplasias de Tejido Fibroso/diagnóstico , Femenino , Humanos , Persona de Mediana EdadRESUMEN
The main problem associated with rectal cancer treatment is tumor recurrence. Randomized controlled studies have shown that adjuvant preoperative radiation therapy is effective for reducing local recurrence. These studies have also demonstrated that there are groups of rectal cancer patients with differing degrees of risk for local recurrence. At one end of the spectrum is the low-risk group: patients with superficial rectal cancer, who can be treated with surgery alone. At the other end is the high-risk group: patients with a close or involved resection margin at total mesorectal excision, the very advanced tumors that require a longer course of chemotherapy and radiation therapy, and extensive surgery. Paramount for this selection and differentiated treatment is a reliable preoperative test that can be used to distinguish these groups of patients. In this review article, we will discuss the role of high-resolution phased array MRI among the other imaging modalities such as endorectal MRI, endorectal US, and CT. We will also discuss and illustrate MR imaging results in terms of T stage, circumferential resection margin, locally advanced rectal cancer, and N stage.
Asunto(s)
Imagen por Resonancia Magnética , Neoplasias del Recto/diagnóstico , Humanos , Imagen por Resonancia Magnética/métodos , Cuidados Preoperatorios/métodos , Neoplasias del Recto/terapiaRESUMEN
OBJECTIVES: To evaluate MR imaging in detecting and characterizing secondary reactive synovitis and correlate the results with arthroscopy. MATERIALS AND METHODS: Retrospective study of 10 patients referred for MR imaging and arthroscopy of the knee or shoulder. The diagnosis of reactive synovitis was confirmed by arthroscopy and pathological examination. Synovial thickening was graded at MRI as follows. Grade 0: normal; grade 1: diffuse synovial thickening; grade 2: nodular synovial hypertrophy; grade 3: pseudotumoral synovial mass. RESULTS: Synovitis was described at MRI in 8 cases. There were 2 false negative results on MR imaging for the knee. Synovitis was secondary to knee trauma and rotator cuff tear or surgery of the shoulder. On arthroscopy, all synovial lesions were detected and confirmed at pathology. Synovitis was not detected at MRI (grade 0) in 20% of cases. Synovitis appeared diffuse (grade 1) in 30%, nodular (grade 2) in 30% and pseudotumoral (grade 3) in 20%. Bony erosions were adjacent to synovial thickening in 5 cases. CONCLUSION: Reactive synovitis can occur after trauma. MR imaging is useful in detecting and evaluating secondary reactive synovitis. Arthroscopy and synovial biopsy are necessary to exclude infectious or tumoral synovitis.
Asunto(s)
Artroscopía , Imagen por Resonancia Magnética , Sinovitis/diagnóstico , Adulto , Reacciones Falso Negativas , Femenino , Granuloma de Células Plasmáticas/diagnóstico , Humanos , Hipertrofia , Traumatismos de la Rodilla/complicaciones , Articulación de la Rodilla/patología , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Lesiones del Manguito de los Rotadores , Rotura , Articulación del Hombro/patología , Articulación del Hombro/cirugía , Sinovitis/etiologíaRESUMEN
Iatrogenic drug disorders should be considered when presented with a number of imaging findings mainly involving the nervous, musculoskeletal, gastrointestinal or genitourinary system. Care should be used when differentiating between imaging findings related to the underlying pathology and imaging findings related to drug-related complications: examples include the impact of steroid therapy on bones and the impact of triple-drug anti-HIV therapy and its impact of fatty tissue. Knowledge of the necessary imaging surveillance protocol is implied.
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Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos , Enfermedad Iatrogénica , Adolescente , Adulto , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Tomografía Computarizada por Rayos XAsunto(s)
Hematoma/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Pleura , RadiografíaRESUMEN
We report two cases of acute aortic thrombosis in cancer patients. Aortic thrombosis is rare in the absence of atherosclerosis, dissection, or aneurysm. On the one hand, hypercoagulable state related to cancer is a well-known risk factor for venous thrombosis. On the other hand, arterial thrombosis has been rarely reported in cancer patients. Recognition of aortic thrombosis is important because it is a dangerous condition; furthermore, it exposes at the patient to complications such as peripheral embolism. In addition, anticoagulation can result in resolution of thrombosis.
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Adenocarcinoma/complicaciones , Aorta Abdominal/diagnóstico por imagen , Enfermedades de la Aorta/diagnóstico , Neoplasias Hepáticas/secundario , Linfoma de Células T/complicaciones , Neoplasias Pancreáticas/complicaciones , Trombosis/diagnóstico , Enfermedad Aguda , Adenocarcinoma/patología , Anticoagulantes/uso terapéutico , Antihipertensivos/uso terapéutico , Enfermedades de la Aorta/complicaciones , Enfermedades de la Aorta/tratamiento farmacológico , Medios de Contraste/administración & dosificación , Femenino , Estudios de Seguimiento , Heparina/uso terapéutico , Humanos , Masculino , Persona de Mediana Edad , Neoplasias Pancreáticas/patología , Arteria Renal/diagnóstico por imagen , Trombosis/complicaciones , Trombosis/tratamiento farmacológico , Tomografía Computarizada Espiral/métodos , UltrasonografíaRESUMEN
Intramural hematoma of the colon is a rare complication of blunt abdominal trauma. We report the case of a 32-year-old man who presented with abdominal pain related to blunt trauma. The initial diagnosis of post-traumatic intramural hematoma of the colon was performed at CT scan and proven at colonoscopy. Although the majority of cases warrant surgery, conservative therapy was proposed in the present case with spontaneous resolution of the hematoma demonstrated by CT scan.
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Colon/lesiones , Enfermedades del Colon/etiología , Hemorragia Gastrointestinal/etiología , Hematoma/etiología , Heridas no Penetrantes/complicaciones , Adulto , Enfermedades del Colon/diagnóstico por imagen , Hemorragia Gastrointestinal/diagnóstico por imagen , Hematoma/diagnóstico por imagen , Humanos , Masculino , Tomografía Computarizada por Rayos XRESUMEN
The objective of the present study was to assess the efficiency and benefit of a chemomechanical system for carious dentin removal, Carisolv, in general practice. A revised caries classification, the site/stage concept, was used to describe the clinical situations of all carious lesions treated. The study was performed by 12 investigators, and 120 carious lesions were treated with Carisolv. Sixty percent of the cases were treated without anaesthesia, and we found a significant correlation between chemomechanical treatment without anaesthesia and absence of pain ( P=0.01). In 78.3% of the cases, carious dentin was totally removed with Carisolv, and in 21.7%, the dentin treatment was completed by drilling. In cases performed with Carisolv alone, the time required to remove carious dentin was 11.1+/-9.51 min (mean+/-SD). Treatment time was equivalent for all sites and increased significantly with each successive stage of lesion progression ( P<0.001). In 82.5% of cases, the clinicians were satisfied with Carisolv, and in 99.2%, so were the patients. We conclude that, using clinical examination methods, Carisolv seems to remove carious dentin at all sites and stages of carious lesions but must be made more efficient for use in general practice.
Asunto(s)
Caries Dental/clasificación , Caries Dental/terapia , Preparación de la Cavidad Dental/métodos , Ácido Glutámico/uso terapéutico , Leucina/uso terapéutico , Lisina/uso terapéutico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Anestesia Dental , Niño , Dentina , Femenino , Humanos , Masculino , Persona de Mediana Edad , Satisfacción del Paciente , Estudios Prospectivos , Encuestas y Cuestionarios , Factores de TiempoRESUMEN
Myositis ossificans circumscripta is a benign pathology of soft tissue occurring in young patients often after localized trauma. Histological and radiological appearances may mimic a malignant neoplasm, mainly sarcoma. We report a case characteristic of myositis ossificans circumscripta, to illustrate diagnostic arguments which are based on their appearance on conventional radiographs, computed tomography and magnetic resonance imaging and on their changes with time.
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Imagen por Resonancia Magnética , Miositis Osificante/diagnóstico , Tomografía Computarizada por Rayos X , Adulto , Diagnóstico Diferencial , Progresión de la Enfermedad , Mano , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Miositis Osificante/etiología , Miositis Osificante/fisiopatología , Dolor/etiología , Factores de Tiempo , Tomografía Computarizada por Rayos X/métodosRESUMEN
Patient's age no longer is a major factor when discussing the diagnosis and treatment of hepatobiliary and gastrointestinal diseases. However, discussing with the physician in charge of the patient is the only adequate way to propose the quickest, least invasive and most comfortable imaging modality that will give a proper answer to the clinical problem. Cross sectional imaging, especially ultrasound, CT and in some cases MRI, plays an important role in the diagnosis of these diseases.