Editorial [Clinical Applications of Advanced CT, MRI and Optical Imaging's as Well as Spect]

Computed tomography (CT) has already been proven reliable in the evaluation of various mass lesions, and multidetector CT allows the entire organ to be imaged during a single breath hold with thin collimation. The near isotropic pixels also enable the production of multiplanar reformatted images and three-dimensional renderings. CT urography before and after injection of iodinated contrast agent has been proposed as a comprehensive evaluation of the urinary tract. Cystoscopy remains the reference standard for bladder cancer detection and it is invasive and uncomfortable. CT virtual cystoscopy may potentially prevent cystoscopy in some patients. Dr. Tsili et al. stress the advantages of CT cystoscopy in the detection of bladder cancer which is the most common malignancy of the urinary tract. CT colonography is frequently used to examine the colorectum for polyps and masses. Recently, the American Cancer Society endorsed the use of CT colonography for the screening of colorectal cancer in asymptomatic adults with average risk starting at age 50. Reader experience and training are recognized as important factors in achieving acceptable diagnostic accuracy. Dr. Sangwaiya et al. describe the optimal technique for CT colonography and define its role in the colorectal cancer screening strategy. Over the last decade, diffusion tensor imaging (DTI) has arisen as one of the biggest advances in clinical imaging. Diffusion describes the stochastic movement of molecules in liquids. This movement is isotropic in unconstrained media. Diffusion barriers in biological tissue yield a preferred spatial direction of the molecular movement, and thus this directionality of diffusion is called anisotropy. The apparent diffusion coefficient (ADC) represents the interaction of the diffusing molecules with cellular structures. Consistent with a decline of cortical connectivity and impairment of axonal and dentritic integrity early in the Alzheimer's disease, DTI showed significant reductions of fractional anisotropy in poetrior white matter areas. Dr. Ito reviews changes in diffusion properties in the brain observed in patients with Alzheimer's disease. Interbody spacers for anterior spine fusion are made of different materials which produce susceptibility artifacts on postfusion MRI scans. Dr. Ernstberger et al. focus on the influence of determined implant parameters such as shape and volume from selected implant materials and MRI pulse sequences and concludes that significant differences with regard to the total artifact volume could be determined in favor of a cylindric implant shape. Dr. Payne et al. review the relative merits and current status of CT, MRI and MR spectroscopy in the planning of radiotherapy. He also discusses co-registrations of MRI and CT as well as MRI and MR spectra. Recently, improved imaging techniques such as high resolution ultrasound, CT and single photon emission tomography have fostered the widespread adoption of minimally invasive parathyroidectomy (MIP) for better cosmesis, reduced postoperative pain, shorter length of hospital stay and quicker return to preoperative activity level. Dr. Adler et al. review a radioguided MIP with details of indications, techniques, special situations and futuristic view. F-18 fluordeoxyglucose (FDG) positron emission tomography (PET) has demonstrated high accuracy in the staging and therapeutic evaluation of colorectal and esophageal cancers. Dr. Chin reviews the currently established and emerging clinical indications, diagnostic accuracies as well as limitations of PET/CT in patients with various gastrointestinal tumors including pancreatic, hepatocellular and gastric cancers. Optical coherence tomography (OCT) is recently emerging noninvasive imaging modality and is increasingly important diagnostic tool in various medical applications. However, one of its limitations is the presence of speckle noise which obscures small and low-intensity features. Many different approaches have been proposed, but it is unclear how these methods compare to each other and to the best available single resolution despeckling technique. Dr. Pizurica et al. generate a software phantom and show significant differences in the performance of the analyzed methods. They also conclude that wavelet techniques perform much better than the single resolution ones.