Masked volume wise principal component analysis of small adrenocortical tumours in dynamic [11C]-metomidate positron emission tomography

<p>Abstract</p> <p>Background</p> <p>In previous clinical Positron Emission Tomography (PET) studies novel approaches for application of Principal Component Analysis (PCA) on dynamic PET images such as Masked Volume Wise PCA (MVW-PCA) have been introduced. MVW-PCA was shown to be a feasible multivariate analysis technique, which, without modeling assumptions, could extract and separate organs and tissues with different kinetic behaviors into different principal components (MVW-PCs) and improve the image quality.</p> <p>Methods</p> <p>In this study, MVW-PCA was applied to 14 dynamic 11C-metomidate-PET (MTO-PET) examinations of 7 patients with small adrenocortical tumours. MTO-PET was performed before and 3 days after starting per oral cortisone treatment. The whole dataset, reconstructed by filtered back projection (FBP) 0–45 minutes after the tracer injection, was used to study the tracer pharmacokinetics.</p> <p>Results</p> <p>Early, intermediate and late pharmacokinetic phases could be isolated in this manner. The MVW-PC1 images correlated well to the conventionally summed image data (15–45 minutes) but the image noise in the former was considerably lower. PET measurements performed by defining "hot spot" regions of interest (ROIs) comprising 4 contiguous pixels with the highest radioactivity concentration showed a trend towards higher SUVs when the ROIs were outlined in the MVW-PC1 component than in the summed images. Time activity curves derived from "50% cut-off" ROIs based on an isocontour function whereby the pixels with SUVs between 50 to 100% of the highest radioactivity concentration were delineated, showed a significant decrease of the SUVs in normal adrenal glands and in adrenocortical adenomas after cortisone treatment.</p> <p>Conclusion</p> <p>In addition to the clear decrease in image noise and the improved contrast between different structures with MVW-PCA, the results indicate that the definition of ROIs may be more accurate and precise in MVW-PC1 images than in conventional summed images. This might improve the precision of PET measurements, for instance in therapy monitoring as well as for delineation of the tumour in radiation therapy planning.</p

Laparoscopic adrenalectomy: lessons learned from 306 cases

INTRODUCTION: Laparoscopic adrenalectomy has become the standard of care for the surgical treatment of benign adrenal pathology. We present the following case series documenting our experience in refinement of this approach. PAIENTS AND METHODS: Analysis of patient records identified those in whom laparoscopic adrenalectomy was performed from January 1997 through February 2010. Study variables included indications, operative time, blood loss, length of hospital stay, histopathological evaluation, and complications. ----- RESULTS: Laparoscopic adrenalectomy was performed in 306 patients using the transperitoneal lateral approach. No major operative complications were noted, and postoperative complications included a pulmonary embolism and 2 cases of pneumonia. Conversion to the open approach was necessitated in two cases. The median operative time was 95±29 minutes (range, 45-145 minutes). Estimated blood loss was 60 mL (range, 30-150 mL). The mean size of the removed gland was 5.9±1.6 cm (range, 3-13 cm). The mean size of the tumor was 5±2 cm (range, 0.5-12 cm). The median hospitalization was 4±3.7 days (range, 2-22 days). Adrenal pathology included adenoma (n=164), pheochromocytoma (n=79), hyperplasia (n=35), metastatic carcinoma (n=22), cyst (n=9), myelolipoma (n=9), hemangioma (n=3), ganglioneuroma (n=3), and melanoma (n=2). ----- CONCLUSION: Laparoscopic adrenalectomy is a safe and feasible approach to adrenal pathology, providing the patients with all the benefits of minimally invasive surgery