Editorial

In this May issue of CMIR there are again excellent papers dealing with clinical applications of advanced neuroimaging techniques which evaluate either directly or indirectly image the structure as well as function or pharmacology. In addition, there is a paper proposing algorithms of the comprehensive pre- and posttherapeutic imaging for the locoregional treatment of metastatic colorectal cancer in the liver. The bicaudate index (BCI) is the ratio of the width of both lateral ventricles at the level of the heads of the caudate nuclei to the distance between the outer tables of the skull at the same level. Hungting's disease has shown to have more than double of contrl BCI. Bonifacic reports that BCI progressively increases after the age of 50 and rises to levels that nearly double those found in the age group of 30 or younger. The concept of lacunar stroke is still controversial because of different definitions of lacunes have been used. Originally, lacunes were defined pathologically as small subcortical infarcts in the territory of the deep penetrating arteries, but they now are diagnosed on clinical and imaging methods. Gunda et al. summarize recent knowledge about the capacity of various imaging modalities to identify lacunar infarcts and judge their clinical relevacne as well as for the differential diagnosis and mechanisms to produce small subcortical infarcts. Mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) is one of the family of mitochondrial cytopathies caused by defects in the mitochondrial genome. It affects many of the body's systems, particularly the brain, nervous system and muscles. Most affected individuals experience stroke-like episodes beginning before age 40 and have a buildup of lactic acid in their bodies including bloods. Munoz et al. describe neuroimaging patterns of the most common MELAS affecting children on conventional MRI as well as diffusion-weighted imaging and proton MR spectroscopy in two parts. MR spectroscopy has provided objective neurochemical information, therby altering treatment, when MRI is indeterminate in evaluating brain tumors. Methods of quantifying tumor metabolites under in vivo MR spectral profiles have been progressively developed to improve diagnostic accuracy. Most of them are not always directly applicable to cancer lesions because of their inherent heterogeneity, and thus peak area ratios may be better indicators of disease progression and therapeutic response in some cases. Canese et al. overview the principal methods currently applied for the quantification of metabolites detected by proton MR spectroscopy in tumors. Locally ablative treatment of hepatic colorectal metastases is still lacking of large controlled trials to definitely prove its benefits on the patient survival in contrast to surgical or cytostatic therapy. Many different modalities have been developed for minimally invasive locoregional treatments such as radiofrequency ablation, laser induced thermotherapy or transarterial radioembolization. All of these modalities have been performed under imaging guidance, but there are not yet comprehensive guidelines on the use of locally ablative therapies. Algorithms are needed for pretherapeutic decision making regarding the appropriate treatment strategy as well as for posttherapeutic followup of treatment response. Schnapauff et al. review current opinions to the use of diagnostic imaging for differrent image-guided treatments and also proposed comprehensive pre- and posttherapeutic imaging algorithms.