The value of 18F-FDG PET/contrast-enhanced CT in detection of tumor thrombus

PURPOSE: The differentiation between tumor and bland thromboses is important as the management differs. Retrospectively, we aim to evaluate the utility of FDG PET in detecting and differentiating tumor from bland thromboses and if FDG PET provides additional value to contrast-enhanced CT for tumor thrombus detection. PATIENTS AND METHODS: Twenty-four sites of venous thromboembolism, detected on PET/CT, were retrospectively reviewed. Classification of type of thrombosis was based on histology and radiological follow-up. We evaluated the presence of contrast-enhanced CT findings that were suggestive of tumor thrombosis; sign of invasion, neovascularity, and enhancement. Metabolic activity by means of SUV(max) was measured by drawing ROI at the site of thrombosis. Mann-Whitney U test was used to compare the mean SUV(max) between thromboses and internal references. We used ROC analysis to identify the optimal cutoff value of SUV(max) for detection of tumor thrombosis. RESULTS: Twenty-four sites of venous thromboembolism were identified in 15 patients. All tumor thromboses demonstrated at least 1 positive sign on contrast-enhanced CT, whereas 33% of bland thromboses had the same finding. The difference between tumor and bland thrombus SUV(max) was statistically significant (P < 0.005). On ROC analysis, a cutoff of SUV(max) 2.25 (sensitivity, 78%; specificity, 100%) was suggested to differentiate tumor from bland thrombosis. CONCLUSION: PET/CT is able to differentiate tumor from bland thrombosis, with an optimal cutoff value of SUV(max) 2.25. The metabolic information increases the diagnostic accuracy of tumor thrombus and is a useful adjunct to the described features on contrast-enhanced CT.postprin

Automatic detection and classification of nasopharyngeal carcinoma on PET/CT with support vector machine

Purpose: Positron emission tomography/computed tomography (PET/CT) has established values for imaging of head and neck cancers, including the nasopharyngeal carcinoma (NPC), utilizing both morphologic and functional information. In this paper, we introduce a computerized system for automatic detection of NPC, targeting both the primary tumor and regional nodal metastasis, on PET/CT. Methods: Candidate lesions were extracted based on the features from both PET and CT images and a priori knowledge of anatomical features and subsequently classified by a support vector machine algorithm. The system was validated with 25 PET/CT examinations from 10 patients suffering from NPC. Lesions manually contoured by experienced radiologists were used as the gold standard. Results: Results showed that the system successfully identified all 53 hypermetabolic lesions larger than 1 cm in size and excluded normal physiological uptake in brown fat, muscles, bone marrow, brain, and salivary glands. Conclusion: The system combined both imaging features and a priori clinical knowledge for classification between pathological and physiological uptake. Preliminary results showed that the system was highly accurate and promising for adoption in clinical use. © The Author(s) 2011.published_or_final_versionSpringer Open Choice, 25 May 201

Advances in imaging of the solitary pulmonary nodule

Objective. To review the radiological management of a solitary pulmonary nodule. Data sources. MEDLINE literature search (1958-2002). Study selection. All review articles and original articles. Key words for the literature search were 'solitary pulmonary nodule' and 'imaging'. Data extraction. All relevant information and data. Data synthesis. The solitary pulmonary nodule remains a perennial problem in radiological practice, particularly with current trends using low-dose computed tomography to screen for lung cancer. Determining the likelihood of malignancy forms the basis of the radiological approach of a solitary pulmonary nodule. Several factors that influence risk analysis include morphological and enhancement characteristics of the solitary pulmonary nodule on imaging, stability of the nodule, age of patient, smoking history, and history of malignant disease. Other ancillary procedures and imaging techniques that assist in the evaluation of a solitary pulmonary nodule include fluorodeoxyglucose positron-emission tomography, technetium Tc 99m depreotide imaging, bronchoscopy with bronchioloalveolar lavage and biopsy, image-guided transthoracic needle aspiration biopsy, video-assisted thorascopic surgery, and thoracotomy. Conclusions. The success of any radiological management of a solitary pulmonary nodule rests on careful clinical evaluation and risk stratification for malignancy before the implementation of appropriate imaging techniques.published_or_final_versio

Thalamic T2 Hyperintensities and Cognitive Function in Chinese Children With NF-1

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Peritoneal dissemination: comparison of 18F-FDG PET/CT and DWI with conventional MRI

Scientific Formal (Paper) Presentation - SSK13: Nuclear Medicine (Oncology)PURPOSE: The purpose of this study was to evaluate the diagnostic performance of 18F-FDG PET/CT in peritoneal dissemination detection, in comparison to MRI with and without diffusion-weighted imaging (DWI). METHOD AND MATERIALS: Prospective subjects with peritoneal metastases were recruited for 18F-FDG PET/CT and MRI, performed within 4-week of each other, without intervening therapeutic interventions. Images were evaluated in separate sessions as following: DWI alone, conventional MRI alone, DWI with conventional MRI, and 18F-FDG PET/CT for peritoneal dissemination in 16 anatomical ...postprin

18F-FDG-PET-CT imaging findings of recurrent intracranial haemangiopericytoma with distant metastases

A 42-year-old woman presented with local recurrence and distant lung and liver metastases 7 years after resection of a primary intracranial haemangiopericytoma. Whole-body 18F-fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography (PET)-CT scan showed no increased uptake in local recurrence or distant metastases except for a focus of increased FDG uptake within a hepatic metastasis. The hypermetabolic area correlated with an intratumoral hypoenhancing area on the CT scan. PET-CT scan may be useful to allow further understanding of the tumour. © 2010 The British Institute of Radiology.link_to_subscribed_fulltex

Characterization of white matter reorganization in neonatal hypoxic-ischemic cerebral injury using diffusion tensor imaging

Animal Models of Ischemia: Characterization - Poster presentationThis study employs in vivo diffusion tensor imaging (DTI) to understand the late changes in white matter (WM) injury and reorganization in the rat brain upon neonatal hypoxic-ischemic cerebral injury. In particular, detailed inspection of the color-encoded fractional anisotropy (FA) map of the principal eigenvector was performed to compare the orientations of the high FA fibers at the perilesional areas with the WM microstructures in the contralateral hemisphere. In addition to the differences in DTI parameters in the microstructures between both hemispheres, results showed that the perilesional areas had similar fiber orientations as the contralateral external capsule in the anterior section of the brain, and as the internal capsule and the fimbria of hippocampus in the posterior section. We demonstrated that DTI can detect the microstructure and orientations of WM fiber changes at the perilesional areas in vivo, and can be used for non-invasive evaluation of HI brain injuries and reorganization.published_or_final_versionThe 17th Scientific Meeting & Exhibition of the International Society of Magnetic Resonance in Medicine (ISMRM), Honolulu, HI., 18-24 April 2009. In Proceedings of ISMRM 17th Scientific Meeting & Exhibition, 2009, p. 327

Partial rhombencephalosynapsis and Chiari II malformation

We report a rare case of partial rhombencephalosynapsis coexistent with Chiari II malformation in a 6-year-old girl and discuss the features of these entities on magnetic resonance imaging.published_or_final_versio

A case of cerebellar hypoplasia in a Chinese infant with osteogenesis imperfecta

We report a unique case of unilateral cerebellar hypoplasia in a young Chinese girl with osteogenesis imperfecta type IV. Magnetic resonance imaging showed mild basilar invagination and impression. Although unilateral cerebellar hypoplasia and osteogenesis imperfecta may have been coincidental diagnoses, we propose possible mechanisms for unilateral cerebellar hypoplasia secondary to osteogenesis imperfecta. For example, cerebellar hypoplasia may have been because of vascular disruption or direct compression to the posterior circulation in utero. Foetuses with osteogenesis imperfecta are more susceptible to the above risks compared to the normal foetus because of associated craniocervical anomalies and a poorly ossified skull.published_or_final_versio

Osteoporotic insufficiency fractures of the pelvis

Insufficiency fractures are a subtype of stress fractures which occur when normal or physiological stresses are placed on weakened bone. The main predisposing cause is osteoporosis. The clinical and radiological features of two elderly women with pelvic insufficiency fractures are described. Isotope bone scan is the most sensitive imaging modality for the detection of these fractures. Computed tomography is useful for confirming these fractures and excluding malignancy. As pelvic insufficiency fractures are difficult to detect clinically, application of the appropriate radiological investigation is necessary for diagnosis. With early recognition of this entity, the patient could be managed appropriately, thus avoiding any unnecessary invasive investigations.published_or_final_versio