Current Medical Imaging - Volume 10, Issue 3, 2014

CT perfusion offers vital blood flow and volume information for patients presenting with stroke. This information can be used to provide a more informed treatment. A popular approach for the solution of physiologic parameters using CT perfusion calculates a residual function as an intermediary result, using Singular Value Decomposition (SVD) for deconvolution. Typically in clinical use, only the final parameters are provided by the algorithm. The calculation process can in some cases be unstable and give widely varying results based on the addition of very small amounts of noise or small differences in tracer arrival times. The examination of the residual function can provide insight into the stability of SVD based methods. Several methods have been proposed to reduce noise and stabilize the solutions. We utilize simulations to to examine common parameter estimation approaches and assess their stability and accuracy.

Oncological diseases are getting immense importance in today’s Health care scenario. Computational applications have critical role in medical applications. Accurate detection of abnormal mass in an early stage is essential for its treatment and hence increases the survival rate. Advanced Imaging Techniques play a great role to detect these abnormalities or tumour. But manual detection of these abnormalities or tumour especially in Magnetic Resonance Imaging (MRI) or Computed Tomography (CT) of brain may misdiagnose the result and give poor performance because of heterogeneous nature of tumour. Although many automated and semi automated methods are available to diagnose tumour but each has its own limitations and there is no final, state-of-the art technique to date which is able to be implemented in real scenario. This survey paper is based on techniques used to segment the normal and abnormal brain, analysis of their merits and demerits and their applications on advanced imaging techniques.

The paper investigates four major issues in the active field of lung computer aided diagnosis (CAD) using content-based image retrieval (CBIR), which are: creating an efficient feature index for lung nodules for similarity measures, database creation of nodules with proven pathology, robust CBIR system and present a self-diagnosing environment to assist the physician in taking the right decision at right time. The results definitely improves the radiologists performance of detecting suspicious nodules based on the ground truth prepared. CBIR has been implemented to expand the small ground truth of 17 nodules to ground truth of 114 nodules based on available biopsy report. Nine out of 83 different extracted features have been considered as the best discriminating features to classify the lung nodules in three classes: Malignant, Benign and Metastasis. LIDC database has been analysed and achieved an average precision of 92.8% , mean average precision (MAP) of 82% at recall 0.1 and an average precision of 88% with PGIMER, Chandigarh. Results in this paper also indicate that the unnecessary biopsies can be avoided as the results are having few number of false positives which can directly increase the specificity of the proposed research.

Urinary continence depends on, an intact internal urethral sphincter (IUS) with a high alpha-sympathetic tone gained by learning in childhood both create high urethral pressure. The IUS is a collagen-muscle tissue cylinder that extends from the bladder neck to the perineal membrane in both sexes. Childbirth trauma causes injury to the vagina and the intimately lying IUS. It lacerates the collagen frame of the IUS. A weak torn IUS will not stand sudden rise of abdominal pressure and urine leaks, stress urinary incontinence (SUI). Imaging with three-dimension ultrasound (3DUS) and MRI demonstrate the torn IUS and show the site and extent of the injury. Torn upper part of the IUS causes funneling and apparent descent of the bladder neck and leads to overactive bladder. Torn lower part leads to genuine SUI. Injury to the whole length leads to mixed- type of urinary incontinence and apparent shortening of the urethra with collapsed torn walls. Fecal continence depends on a closed anal canal that depends on the integrity of both anal sphincters, the internal anal sphincter (IAS) and the external anal sphincter (EAS). It also depends on intact reactive nervous system and on an acquired high alpha-sympathetic tone at the IAS gained by training in early childhood. The IAS is a collagen-muscle tissue cylinder that surrounds the anal canal with the EAS surrounds it in its lower part. Torn EAS is obvious, but only imaging with 3DUS and MRI show an open anal canal with torn IAS in cases of fecal incontinence.

Infection countinue to be a significant health problem and the cause of patient mortality and morbidity especially in developing countries. Accurate and timely detection of infection and inflammation may have essential implications for the managing of patients. Imaging by nuclear medicinal techniques, due to its high sensitivity, offers a fascinating choice for diagnosis of infectious foci. The use of radiopharmaceuticals for targeting of infection specifically is increasing because of their ability to distinguish between septic and aseptic inflammation. Specific targeting of the microorganisms is the main strategy for enhancing the selectivity of new radiopharmaceuticals for imaging of infective lesions. In this context, radiolabeled antibiotics and antimicrobial peptides are thoroughly studied in order to investigate their diagnostic value as specific imaging agents. In this review, the aspects of presently used radiopharmaceuticals to image infection and inflammatory procedures and their potential to differenciate infection from inflammation are discussed.