Diagnosis of cyst infection in patients with autosomal dominant polycystic kidney disease: attributes and limitations of the current modalities

Cyst infection is a diagnostic challenge in patients with autosomal dominant polycystic kidney disease (ADPKD) because of the lack of specific manifestations and limitations of conventional imaging procedures. Still, recent clinical observations and series have highlighted common criteria for this condition. Cyst infection is diagnosed if confirmed by cyst fluid analysis showing bacteria and neutrophils, and as a probable diagnosis if all four of the following criteria are concomitantly met: temperature of >38°C for >3 days, loin or liver tenderness, C-reactive protein plasma level of >5 mg/dL and no evidence for intracystic bleeding on computed tomography (CT). In addition, the elevation of serum carbohydrate antigen 19-9 (CA19-9) has been proposed as a biomarker for hepatic cyst infection. Positron-emission tomography after intravenous injection of 18-fluorodeoxyglucose, combined with CT, proved superior to radiological imaging techniques for the identification and localization of kidney and liver pyocyst. This review summarizes the attributes and limitations of these recent clinical, biological and imaging advances in the diagnosis of cyst infection in patients with ADPK

Diagnosis of cyst infection in patients with autosomal dominant polycystic kidney disease: attributes and limitations of the current modalities.

Cyst infection is a diagnostic challenge in patients with autosomal dominant polycystic kidney disease (ADPKD) because of the lack of specific manifestations and limitations of conventional imaging procedures. Still, recent clinical observations and series have highlighted common criteria for this condition. Cyst infection is diagnosed if confirmed by cyst fluid analysis showing bacteria and neutrophils, and as a probable diagnosis if all four of the following criteria are concomitantly met: temperature of >38 degrees C for >3 days, loin or liver tenderness, C-reactive protein plasma level of >5 mg/dL and no evidence for intracystic bleeding on computed tomography (CT). In addition, the elevation of serum carbohydrate antigen 19-9 (CA19-9) has been proposed as a biomarker for hepatic cyst infection. Positron-emission tomography after intravenous injection of 18-fluorodeoxyglucose, combined with CT, proved superior to radiological imaging techniques for the identification and localization of kidney and liver pyocyst. This review summarizes the attributes and limitations of these recent clinical, biological and imaging advances in the diagnosis of cyst infection in patients with ADPKD

Positron-emission computed tomography in cyst infection diagnosis in patients with autosomal dominant polycystic kidney disease.

BACKGROUND: Cyst infection remains a challenging issue in patients with autosomal dominant polycystic kidney disease (ADPKD). In most patients, conventional imaging techniques are inconclusive. Isolated observations suggest that (18)fluorodeoxyglucose ((1)(8)FDG) positron-emission computed tomography (PET/CT) might help detect cyst infection in ADPKD patients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Comparative assessment of administrative databases from January 2005 to December 2009 identified 27 PET/CT scans performed in 24 ADPKD patients for suspicion of abdominal infection. Cyst infection was definite if confirmed by cyst fluid analysis. Cyst infection was probable if all four of the following criteria were met: temperature of >38 degrees C for >3 days, loin or liver tenderness, C-reactive protein plasma level of >5 mg/dl, and no CT evidence for intracystic bleeding. Episodes with only two or three criteria were grouped as "fever of unknown origin". RESULTS: Thirteen infectious events in 11 patients met all criteria for kidney (n = 3) or liver (n = 10) cyst infection. CT was contributive in only one patient, whereas PET/CT proved cyst infection in 11 patients (84.6%). In addition, 14 episodes of "fever of unknown origin" in 13 patients were recorded. PET/CT identified the source of infection in nine patients (64.3%), including 2 renal cyst infections. Conversely, PET/CT showed no abnormal (1)(8)FDG uptake in 5 patients, including 2 intracystic bleeding. The median delay between the onset of symptoms and PET/CT procedure was 9 days. CONCLUSIONS: This retrospective series underscores the usefulness of PET/CT to confirm and locate cyst infection and identify alternative sources of abdominal infection in ADPKD patients

Estudio pre/post de los efectos agudos del procedimiento STENDO sobre el rendimiento de la marcha y la adaptación vascular (NIRS) en pacientes con EPOC.

Objetivos: Determinar si el dispositivo STENDO puede mejorar el rendimiento de la marcha en pacientes sintomáticos con EPOC inmediatamente después de la estimulación.Método: Se trata de un estudio experimental, intervencionista, aleatorizado, controlado con placebo (STENDO placebo-controlled) y unicéntrico. Catorce pacientes con EPOC de 67 ± 10 años se sometieron a una prueba de marcha de seis minutos (TM6) pre/post STENDO durante la cual se midieron el intercambio gaseoso pulmonar, la oxigenación muscular mediante NIRS, la saturación arterial pulmonar y el esfuerzo percibido.Resultados: La información principal recogida durante este estudio sobre STENDO muestra que TM6 no distingue ninguna diferencia significativa entre el grupo Placebo (461,7 ± 100,8 m) y el grupo Intervención (448,5 ± 36,14m). Sin embargo, se observó que el dispositivo STENDO aumentó de forma aguda el flujo sanguíneo al flexor radial del carpo en T5, T35 e inmediatamente después de la parada, en comparación con el grupo placebo (p0,05) sin efecto sobre la disnea en comparación con el grupo.Conclusiones: La comparación entre los grupos Placebo e Intervención no estableció que el dispositivo STENDO el rendimiento de la marcha en pacientes sintomáticos con EPOC inmediatamente después de la estimulación. <br /

Role of FDG PET/CT in imaging of renal lesions

Focal incidental renal lesions are commonly encountered on positron emission tomography (PET)/computed tomography (CT) imaging. The vast majority of these lesions are benign. However, the interpretation of renal lesions can be problematic if the imaging criteria of simple cysts are not met. Limited literature exists on the characterisation of renal masses with metabolic imaging. The purpose of this article is to focus on the imaging features of benign and malignant renal masses with PET/CT. The lesions discussed include renal cyst, angiomyolipoma, oncocytoma, renal cell carcinoma, renal metastases and other infiltrating neoplastic processes affecting the kidney. Both the anatomical and metabolic features which characterise these benign and malignant entities are described. We emphasise the importance of viewing the CT component to identify the typical morphological features and discuss how to best use hybrid imaging for management of renal lesions. Metabolic imaging has a promising role in the imaging of renal lesions and can help prevent unnecessary biopsies and ensure optimal management of suspicious lesions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79384/1/j.1754-9485.2010.02181.x.pd

Quantitative Evaluation of Scintillation Camera Imaging Characteristics of Isotopes Used in Liver Radioembolization

Scintillation camera imaging is used for treatment planning and post-treatment dosimetry in liver radioembolization (RE). In yttrium-90 (90Y) RE, scintigraphic images of technetium-99m (99mTc) are used for treatment planning, while 90Y Bremsstrahlung images are used for post-treatment dosimetry. In holmium-166 (166Ho) RE, scintigraphic images of 166Ho can be used for both treatment planning and post-treatment dosimetry. The aim of this study is to quantitatively evaluate and compare the imaging characteristics of these three isotopes, in order that imaging protocols can be optimized and RE studies with varying isotopes can be compared.Phantom experiments were performed in line with NEMA guidelines to assess the spatial resolution, sensitivity, count rate linearity, and contrast recovery of 99mTc, 90Y and 166Ho. In addition, Monte Carlo simulations were performed to obtain detailed information about the history of detected photons. The results showed that the use of a broad energy window and the high-energy collimator gave optimal combination of sensitivity, spatial resolution, and primary photon fraction for 90Y Bremsstrahlung imaging, although differences with the medium-energy collimator were small. For 166Ho, the high-energy collimator also slightly outperformed the medium-energy collimator. In comparison with 99mTc, the image quality of both 90Y and 166Ho is degraded by a lower spatial resolution, a lower sensitivity, and larger scatter and collimator penetration fractions.The quantitative evaluation of the scintillation camera characteristics presented in this study helps to optimize acquisition parameters and supports future analysis of clinical comparisons between RE studies

Abdo-Man: a 3D-printed anthropomorphic phantom for validating quantitative SIRT

BACKGROUND: The use of selective internal radiation therapy (SIRT) is rapidly increasing, and the need for quantification and dosimetry is becoming more widespread to facilitate treatment planning and verification. The aim of this project was to develop an anthropomorphic phantom that can be used as a validation tool for post-SIRT imaging and its application to dosimetry. METHOD: The phantom design was based on anatomical data obtained from a T1-weighted volume-interpolated breath-hold examination (VIBE) on a Siemens Aera 1.5 T MRI scanner. The liver, lungs and abdominal trunk were segmented using the Hermes image processing workstation. Organ volumes were then uploaded to the Delft Visualization and Image processing Development Environment for smoothing and surface rendering. Triangular meshes defining the iso-surfaces were saved as stereo lithography (STL) files and imported into the Autodesk® Meshmixer software. Organ volumes were subtracted from the abdomen and a removable base designed to allow access to the liver cavity. Connection points for placing lesion inserts and filling holes were also included. The phantom was manufactured using a Stratasys Connex3 PolyJet 3D printer. The printer uses stereolithography technology combined with ink jet printing. Print material is a solid acrylic plastic, with similar properties to polymethylmethacrylate (PMMA). RESULTS: Measured Hounsfield units and calculated attenuation coefficients of the material were shown to also be similar to PMMA. Total print time for the phantom was approximately 5 days. Initial scans of the phantom have been performed with Y-90 bremsstrahlung SPECT/CT, Y-90 PET/CT and Tc-99m SPECT/CT. The CT component of these images compared well with the original anatomical reference, and measurements of volume agreed to within 9 %. Quantitative analysis of the phantom was performed using all three imaging techniques. Lesion and normal liver absorbed doses were calculated from the quantitative images in three dimensions using the local deposition method. CONCLUSIONS: 3D printing is a flexible and cost-efficient technology for manufacture of anthropomorphic phantom. Application of such phantoms will enable quantitative imaging and dosimetry methodologies to be evaluated, which with optimisation could help improve outcome for patients