No abstract

(18)F DOPA PET is highly sensitive and specific for detection of pheochromocytomas and has potential as the functional imaging method of the future.

The introduction of FDG-PET in the diagnostic evaluation of SCLC will improve the staging results and affect patient management, and may reduce the number of tests and invasive procedures.

First-generation ACI leads to satisfying clinical results in terms of patient satisfaction, reduction of pain, and improvement in knee function. Nevertheless, full restoration of knee function cannot be achieved. Although MRI reveals lesions in the majority of the cases and the overall MOCART score seems moderate, this could not be correlated with long-term clinical outcomes.

The aim of this study was to define the imaging characteristics of primary and recurrent gastrointestinal stromal tumors (GIST) in computed tomography with respect to the tumor size. Computed tomography was performed in 35 patients with histologically confirmed gastrointestinal stromal tumors and analyzed retrospectively by two experienced and independent radiologist. The following morphologic tumor characteristics of primary ( n=20) and ( n=16) recurrent tumors were evaluated according to tumor size, shape, homogeneity, density compared with liver, contrast enhancement, presence of calcifications, ulcerations, fistula or distant metastases and the anatomical relationship to the intestinal wall, and the infiltration of adjacent visceral organs. Small GIST (<5 cm) showed a sharp tumor margin with homogeneous density and structure on unenhanced and contrast-enhanced images, and were characterized by an intraluminal tumor growth. Intermediate sized GIST (>5-10 cm) demonstrated an irregular shape, inhomogeneous density on unenhanced and contrast-enhanced images, a combined intra- and extraluminal tumor growth with aggressive findings, and infiltration of adjacent organs in 9 primary diagnosed and 2 recurrent tumors. Large GIST (>10 cm), which were observed in 8 primary tumors and 11 recurrent tumors, showed an irregular margin with inhomogeneous density and aggressive findings, and were characterized by signs of malignancy such as distant and peritoneal metastases. Small recurrent tumors had a similar appearance as compared with large primary tumors. Computed tomography gives additional information with respect to the relationship of gastrointestinal stromal tumor to the gastrointestinal wall and surrounding organs, and it detects distant metastasis. Primary and recurrent GIST demonstrate characteristic CT imaging features which are related to tumor size. Aggressive findings and signs of malignancy are found in larger tumors and in recurrent disease. Computed tomography is useful in detection and characterization of primary and recurrent tumors with regard to tumor growth pattern, tumor size, and varied appearances of gastrointestinal stromal tumors, and indirectly gives hints regarding dignity and therefore prognostic outcome.

Grading graft hypertrophy helps to identify patients needing an early shaving of the graft. Its integration into an MRI score improves correlation with clinical scores. Re-operation depends on the grade of hypertrophy and clinical symptoms.

The purpose of this study was to evaluate (18)F-DOPA whole-body positron emission tomography ((18)F-DOPA PET) as a biochemical imaging approach for the detection of glomus tumours. (18)F-DOPA PET and magnetic resonance imaging (MRI) were performed in ten consecutive patients with proven mutations of the succinate dehydrogenase subunit D ( SDHD) gene predisposing to the development of glomus tumours and other paragangliomas. (18)F-DOPA PET and MRI were performed according to standard protocols. Both methods were assessed under blinded conditions by two experienced specialists in nuclear medicine (PET) and diagnostic radiology (MRI). Afterwards the results were compared. A total of 15 lesions (four solitary and four multifocal tumours, the latter including 11 lesions) were detected by (18)F-DOPA PET. Under blinded conditions, (18)F-DOPA PET and MRI revealed full agreement in seven patients, partial agreement in two and complete disagreement in one. Eleven of the 15 presumed tumours diagnosed by (18)F-DOPA PET were confirmed by MRI. The correlation of (18)F-DOPA PET and MRI confirmed three further lesions previously only detected by PET. All of them were smaller than 1 cm and had the signal characteristics of lymph nodes. For one small lesion diagnosed by PET, no morphological MRI correlate could be found even retrospectively. No tumour was detected by MRI that was negative on (18)F-DOPA PET. All tumours diagnosed by MRI showed a hyperintense signal on T2-weighted images and a distinct enhancement of contrast medium on T1-weighted images. The mean tumour size was 1.5+/-0.5 cm. (18)F-DOPA PET seems to be a highly sensitive metabolic imaging procedure for the detection of glomus tumours and may have potential as a screening method for glomus tumours in patients with SDHD gene mutations.

18F dopa PET is a promising procedure and useful supplement to morphologic methods in diagnostic imaging of gastrointestinal carcinoid tumors.