Rendimiento diagnóstico de la histerosalpingografía por resonancia magnética: resultados iniciales / Diagnostic performance of magnetic resonance hysterosalpingography: initial results Abstract

Objetivo: Determinar el rendimiento diagnóstico de la histerosalpingografía por resonancia magnética (HSG-RM), utilizando la laparoscopia como método de referencia. Materiales y métodos: Se incluyeron 22 pacientes. A todas se les realizó una HSG-RM con un resonador 1.5 Tesla y luego una laparoscopia con cromotubación. Dos radiólogos examinaron las RM, determinando la permeabilidad tubaria por consenso. Se realizaron análisis descriptivos y de rendimiento diagnóstico. Resultados: La HSG-RM tuvo una tasa de éxito del 91%. La duración del estudio fue 49ą15 minutos, el volumen inyectado 26 ą 16 cm³ y la escala de dolor 30ą 19 de 100. La sensibilidad y especificidad de la HSG-RM fueron del 100% para la prueba de Cotte global y a la izquierda, y del 25% y 93,3% para la prueba de Cotte a la derecha, respectivamente. Hubo 2 complicaciones menores y ninguna importante. Discusión: Nuestros resultados iniciales demostraron una alta sensibilidad y especificidad. Si bien otros estudios analizaron la capacidad de la HSG-RM para evaluar la permeabilidad tubaria con buenos resultados, el uso de un patrón de referencia defectuoso dejaba margen para una duda razonable, impidiendo una recomendación basada en pruebas sólidas. Sin embargo, al cotejar nuestros resultados con los publicados, observamos un alto grado de concordancia en tanto el derrame positivo se diagnostica correctamente con una especificidad de 100% o con un porcentaje cercano a esta cifra. Conclusión: La HSG-MR es una alternativa factible y segura de la HSG convencional o virtual, la histerosonografía y la cromotubación.

Objective: To determine the diagnostic performance of magnetic resonance hysterosalpingography (MRHSG) using laparoscopic chromotubation as a method of reference. Materials and methods: Twenty-two patients were included. The MRHSG was performed in a 1.5 Tesla MR scanner. Afterwards, patients underwent laparoscopic chromotubation. MR images were examined by two trained radiologists, and tubal patency was determined by consensus. A descriptive analysis was carried out, as well as an analysis of the diagnostic performance. Results: MRHSG had a 91% success rate. Exam duration of the examination was 49ą15min, with an injected volume 26ą 16cc, and pain scale 30ą 19 out of 100. Sensitivity and specificity of MRHSG was 100% for global and left Cotte, and 25% and 93.3% for right Cotte, respectively. Only 2 minor and no major complications were observed. Discussion: The initial results of MRHSG have shown high sensitivity and specificity. Even though other studies have analysed the potential of MRHSG with good results, the use of a flawed reference standard left a margin for a reasonable doubt as regards its true potential, thus preventing a solid evidence based recommendation. Nevertheless, if our results are compared to those published, a high level of agreement is observed in that positive spillage is correctly diagnosed with specificities near or at 100%. Conclusion: MRHSG is a feasible and safe alternative to conventional or virtual HSG, ultrasound-hysterography and chromotubation.

Optimization of the protocols for the use of contrast agents in PET/CT studies. / Optimización de los protocolos y del uso de contrastes en tomografía computarizada de los equipos de tomografía por emisión de positrones.

The introduction of PET/CT scanners in clinical practice in 1998 has improved care for oncologic patients throughout the clinical pathway, from the initial diagnosis of disease through the evaluation of the response to treatment to screening for possible recurrence. The CT component of a PET/CT study is used to correct the attenuation of PET studies; CT also provides anatomic information about the distribution of the radiotracer. CT is especially useful in situations where PET alone can lead to false positives and false negatives, and CT thereby improves the diagnostic performance of PET. The use of intravenous or oral contrast agents and optimal CT protocols have improved the detection and characterization of lesions. However, there are circumstances in which the systematic use of contrast agents is not justified. The standard acquisition in PET/CT scanners is the whole body protocol, but this can lead to artifacts due to the position of patients and respiratory movements between the CT and PET acquisitions. This article discusses these aspects from a constructive perspective with the aim of maximizing the diagnostic potential of PET/CT and providing better care for patients.

N staging of lung cancer patients with PET/MRI using a three-segment model attenuation correction algorithm: initial experience.

OBJECTIVES: Evaluate the performance of PET/MRI at tissue interfaces with different attenuation values for detecting lymph node (LN) metastases and for accurately measuring maximum standardised uptake values (SUVmax) in lung cancer patients. MATERIALS AND METHOD: Eleven patients underwent PET/CT and PET/MRI for staging, restaging or follow-up of suspected or known lung cancer. Four experienced readers determined the N stage of the patients for each imaging method in a randomised blinded way. Concerning metastases, SUVmax of FDG-avid LNs were measured in PET/CT and PET/MRI in all patients. A standard of reference was created with a fifth experienced independent reader in combination with a chart review. Results were analysed to determine interobserver agreement, SUVmax correlation between CT and MRI (three-segment model) attenuation correction and diagnostic performance of the two techniques. RESULTS: Overall interobserver agreement was high (κ = 0.86) for PET/CT and substantial (κ = 0.70) for PET/MRI. SUVmax showed strong positive correlation (Spearman's correlation coefficient = 0.93, P < 0.001) between the two techniques. Diagnostic performance of PET/MRI was slightly inferior to that of PET/CT, without statistical significance (P > 0.05). CONCLUSIONS: PET/MRI using three-segment model attenuation correction for LN staging in lung cancer shows a strong parallel to PET/CT in terms of SUVmax, interobserver agreement and diagnostic performance. KEY POINTS: •F18-FDG PET/MRI shows similar performance to F18-FDG PET/CT in lung cancer N staging. •PET/MRI has substantial interobserver agreement in N staging. •A three-segment model attenuation correction is reliable for assessing the mediastinum.

[Positron emission tomography/magnetic resonance: Present and future]. / Tomografía por emisión de positrones/resonancia magnética: presente y futuro.

PET/MRI has recently been introduced onto the market after several years of research and development. The simple notion of combining the molecular capabilities of the PET and its difference available radiotracers with the excellent tissue resolution of the MRI and wide range of multiparametric imaging techniques has generated great expectations upon the possible uses of this technology. Many challenges must be worked out. However, the most urgent one is the derivation of the MRI-based attenuation correction map. This is especially true because the PET/CT has already demonstrated a huge clinical impact within oncology, neurology and cardiology during its short existence. Despite these difficulties, research is being carried out at a rapid pace in the clinical setting in order to find areas in which the PET/MRI is superior to other existing imaging modalities. In the few initial publications found up to date that have analyzed its clinical role, areas have been identified where PET/CT can migrate to PET/MRI, even if only to suppress the CT scan's ionizing radiation. Nonetheless, there are many theoretical applications in which the PET/MRI can further improve the field of diagnostic imaging. In this article, we will review those applications, the evidence existing regarding the MRI and PET that support those premises as well as that which we have learned in the short period of one year with our experience using the PET/MRI.

Pulmonary intravascular lymphoma detected by FDG PET-CT: a case report.

Intravascular lymphoma is a rare subtype of extranodal Non-Hodgkin's lymphoma. Its prognosis is poor in a high percentage of cases due to its insidious appearance and low clinical suspicion. Its diagnosis is usually only reached after an autopsy. It may affect different organs as a whole or only one organ. It is extremely rare that the lung is the only damaged organ. Its diagnosis depends of the clinician's suspicion and proper evaluation with imaging studies as well as correct selection of the organ to be biopsied. When detected on time, the treatment of choice is a combination of a series of chemotherapy associated to a monoclonal antibody (anti-CD20). We present the case of a male patient who underwent a positron emission tomography-computed tomography with 2-[F-18]-fluoro-2 deoxy-D-glucose (FDG) due to symptoms suggestive of a lymphoproliferative disease with no clear structural abnormalities. The images led to a diagnosis of pulmonary intravascular large B cell lymphoma.