The Effect of Low Doses of Acetylsalicylic Acid on the Occurrence of Rectal Aberrant Crypt Foci.

Background and Objectives: Aberrant crypt foci (ACF) are one of the earliest putative preneoplastic and, in some cases, neoplastic lesions in human colons. Many studies have confirmed the reduction of ACFs and colorectal adenomas after treatment with acetylsalicylic acid (ASA) commonly referred to as ASA; however, the minimum effective dose of ASA and the duration of use has not been fully elucidated. The objective of our study was to assess the significance of low dose ASA (75-mg internally once daily) to study the chemopreventive effect of ASA in ACF and adenomas development in patients taking this drug for a minimum period of 10 years. Materials and Methods: Colonoscopy, combined with rectal mucosa staining with 0.25% methylene blue, was performed on 131 patients. The number of rectal ACF in the colon was divided into three groups: ACF < 5; ACF 5−10; and ACF > 10. Patients were divided into two groups: the "With ASA" group (the study group subjects taking ASA 75-mg daily for 10 years); and "Without ASA" group (control group subjects not taking ASA chronically). The incidence of different types of rectal ACF and colorectal polyps in both groups of subjects was analysed and ascertained. Results: Normal ACF was found in 12.3% in the study group vs. 87.7% control group, hyperplastic 22.4% vs. 77.6%, dysplastic 25% vs. 75%, mixed 0% vs. 100%. Treatment with ASA affects the occurrence of colorectal adenomas. The amount of dysplastic ACFs was lower in the study group than in the control group. The increase in dysplastic ACFs decreases with age in both groups, with the increase greater in those not taking ASA. Conclusions: Patients who take persistent, chronic (>10 years) low doses of ASA have a lower total number of all types of rectal ACFs and adenomas compared to the control group.

Genotypes and Variants of BKPyV in Organ Donors after Brain Death.

Kidney transplantation from a donor with latent BKPyV might be the cause of serious complications, such as BK virus-associated nephropathy. The aim of the study was to determine the prevalence of BKPyV infection in donors after brain death (DBDs), to analyse the molecular variation of BKPyV and to compare clinical and inflammation parameters of DBDs infected with various genotypes of BKPyV. BKPyV was investigated in blood and urine samples of 103 DBDs using PCR followed by sequencing and bioinformatic analysis, and the viral load was assessed by qPCR. Clinical parameters, including cellular markers of inflammation were assessed. The results confirm high prevalence of BKPyV (48%),and genotype IV (49%) over genotype I (43%) and the co-infection with genotypes I and IV in 8.2%. Viral load ranged from 102 to 107 copies/mL, with an average of 1.92 × 106 copies/mL. No specific markers for BKPyV infection were detected among the parameters tested. Infection with genotype I may be associated with the adverse impact on thekidney function, while infection with genotype IV was associated with the anemia Not only the viral load but also the genotype of BKPyV may have an impact on the course of infection.

Molecular Epidemiology and Variation of the BK Polyomavirus in the Population of Central and Eastern Europe Based on the Example of Poland.

The BK polyomavirus (BKPyV) is a widespread pathogen in humans. Polymorphism of the region encoding the VP1 protein of BKPyV provides the basis for classifying the virus into types and subtypes, whose frequency varies depending on geographic location. The aim of our study was to determine the frequency of BKPyV in the Polish population and to assess its variation by analysing polymorphism in the typing region. The study was conducted on 168 healthy, Polish volunteers, whose blood (plasma) and urine were sampled. The virus was detected using PCR, products, sequenced and subjected to bioinformatic analysis. In addition, viral load was assessed by qPCR. The presence of the genetic material of the BK virus was noted in 61/168 urine samples but in none of the plasma sample. Sequencing and phylogenetic analysis confirmed that the BKPyV isolates were of types I and IV, dominant in Europe (63.93% and 36.07%, respectively). All isolates from genotype I belonged to subtype Ib-2, showing polymorphism at position 1809 with a frequency of 61.54% (G1809A) and 38.46% (G1809C). To the best of our knowledge, this is the first study of this magnitude on the genetic variation of BKPyV among healthy volunteers in Poland.

BK Polyomavirus-Biology, Genomic Variation and Diagnosis.

The BK polyomavirus (BKPyV), a representative of the family Polyomaviridae, is widespread in the human population. While the virus does not cause significant clinical symptoms in immunocompetent individuals, it is activated in cases of immune deficiency, both pharmacological and pathological. Infection with the BKPyV is of particular importance in recipients of kidney transplants or HSC transplantation, in which it can lead to the loss of the transplanted kidney or to haemorrhagic cystitis, respectively. Four main genotypes of the virus are distinguished on the basis of molecular differentiation. The most common genotype worldwide is genotype I, with a frequency of about 80%, followed by genotype IV (about 15%), while genotypes II and III are isolated only sporadically. The distribution of the molecular variants of the virus is associated with the region of origin. BKPyV subtype Ia is most common in Africa, Ib-1 in Southeast Asia, and Ib-2 in Europe, while Ic is the most common variant in Northeast Asia. The development of molecular methods has enabled significant improvement not only in BKPyV diagnostics, but in monitoring the effectiveness of treatment as well. Amplification of viral DNA from urine by PCR (Polymerase Chain Reaction) and qPCR Quantitative Polymerase Chain Reaction) is a non-invasive method that can be used to confirm the presence of the genetic material of the virus and to determine the viral load. Sequencing techniques together with bioinformatics tools and databases can be used to determine variants of the virus, analyse their circulation in populations, identify relationships between them, and investigate the directions of evolution of the virus.

The Effect of Smoking on the Number and Type of Rectal Aberrant Crypt Foci (ACF)-First Identifiable Precursors of Colorectal Cancer (CRC).

BACKGROUND: The problem of smoking and its influence on the occurrence of precursors and advanced colorectal cancer is often discussed in the medical literature. Tobacco smoke can provide a non-nutritional source of polycyclic hydrocarbons and other substances which, when combined with an incorrect diet, may play a role in promoting carcinogenesis at the level of the genetic control mechanism. The aim of our study was to assess the effect of smoking on the frequency and type of aberrant crypt foci (ACF) in the rectum and polyps in the large intestine in people who smoke more than 20 cigarettes a day for more than 20 years. METHODS AND FINDINGS: A colonoscopy combined with rectal mucosa staining with 0.25% methylene blue was performed in 131 patients. Each of the study participants gave informed consent to participate in the study. Three bioptates were collected from the foci defined macroscopically as ACF; in cases where there were fewer foci, the number of collected foci was respectively lower. On the colonoscopy day, patients completed the questionnaire regarding epidemiological data used for analysis of factors affecting the occurrence of ACF in the study group. The number of ACF in the colon was divided into three groups: -ACF < 5, 5 < ACF < 10, ACF > 10. In the statistical analysis, numerical data were presented and real numbers, range of arrhythmic means, mean standard deviation, and results of probability distribution. The Student's test, U test, and chi2 were applied in order to determine the significance of differences of means and frequency of events in both groups. The level of significance was set at α = 0.05. Statistica 7.1 and Excel 2010 were used. Most smokers are in the age groups between 51-70 years. In the youngest (31-40 years), single ACF appear first (ACF <5) ACF in the number of 5-10 appear a little later (around 50 years of age) and dynamically increase, reaching a maximum at the age of 60-65.ACF in the number >10 appear at the latest age (55 years old) and their number gradually increases with age (linear growth). The probability of occurrence of ACF in all groups is greater in smokers, and the difference for the ACF group 5-10 and ACF >10 is statistically significant with a significance level of p < 0.05. Apart from ACF normal, all types of ACF are more likely in this group than in non-smokers and these differences are statistically significant with p < 0.05. CONCLUSIONS: Smoking has a significant impact on the number and type of rectal ACF. Smokers have a greater number of ACFs in the rectum than non-smokers, and the most common type is hyperplastic ACF. Smokers are more likely to develop polyps in all sections of the colon compared to non-smokers.

Effect of the Neurofeedback-EEG Training During Physical Exercise on the Range of Mental Work Performance and Individual Physiological Parameters in Swimmers.

The aim of the study was to demonstrate the effects of the Neurofeedback-EEG training during physical exercise on the improvements in mental work performance and physiological parameters. The study examined seven swimmers based on the following anthropometric measurements: body height, body mass and body composition. The Kraepelin's work curve test, EEG and EMG during physical exercise were also performed. The athletes followed 20 Neurofeedback-EEG training sessions on the swimming ergometer for 4 months. Most mean indices of partial measures of the work curve were significantly modified (p < 0.05) following the Neurofeedback-EEG training. Mean level of maximal oxygen uptake in study participants was over 55 ml/kg/min, with statistically significant differences documented between the first and the second measurements. No significant differences were found in the fatigue rate between the measurements 1 and 2. The improved mental work performance following the Neurofeedback-EEG training facilitates optimization of psychomotor activities.

Rectal aberrant crypt foci (ACF) as a predictor of benign and malignant neoplastic lesions in the large intestine.

BACKGROUND: The importance of ACF is not fully explained, however, their number may be a good predictor of synchronous and metachronic adenoma or other polyps whose removal reduces the risk of CRC. Due to the epidemiological and genetic association of ACF with pre-cancer lesions, they may be a potential CRC biomarker. The aim of our study was to show that the number and type of rectal ACF may be a good predictive factor for the presence of polyps located proximally from the splenic flexure and that the type and number of ACF can correlate with the number and specific types of polyps in the large intestine. METHODS: The study included 131 patients who underwent colonoscopy combined with rectal mucosa staining with 0.25% methylene blue. The number of rectal ACF was determined and bioptats were sampled for histopathological examination to assess the type of ACF. Endoscopic ACF assessment criteria given by L. Roncucci were used. The obtained material was subjected to statistical analysis using probability distribution, U-test, t-student test, and chi 2 as well as the Statistica 7.1 software package. RESULTS: The study population was divided into three subgroups according to the number of ACF observed, i.e. ACF < 5, 5-10 and > 10. ACF < 5 were found in 35 patients (29.41%), 5-10 ACF in 70 (58.82%) and ACF > 10 in 14 individuals (11.76%). The study revealed the presence of normal ACF (p = 0.49), hyperplastic ACF (p = 0.34), dysplastic ACF (p = 0.11), and mixed ACF (p = 0.06). A single type of ACF was most commonly observed (n = 88, p = 0.74). In the researched group a larger number of ACF is concurrent with adenomas and hyperplastic polyps. The number of ACF clearly correlates with the dysplasia advancement in the adenoma and the number of polyps found. CONCLUSIONS: Rectal ACF are a useful marker for the presence of cancerous lesions in the proximal and distal sections of the large intestine.

A rare case of the simultaneous location of Echinococcus multilocularis in the liver and the head of the pancreas: case report analysis and review of literature.

BACKGROUND: Echinococcosis multilocularis (Hydatid Disease - HD) is a zoonotic disease caused by the larval form of Echinococcus multilocularis (EM). The main sites for this zoonosis are the Middle East, China, India, Alaska, and Siberia. It is rather rare in Europe. In Poland, the Warmian-Masurian Province is the endemic region for Echinococcus multilocularis. The clinical manifestation of the disease is dependent on the location, the size of the cyst and the development stage of the parasite. Considering the uncommon character of echinococcosis in Central Europe, especially such located in the areas outside the liver and lungs, the authors would like to present a case of coexistence in one patient of two EM foci in the liver and the head of the pancreas. CASE PRESENTATION: We present a clinical case of a 32-year-old man who was diagnosed with a cystic lesion with septa and calcification in the sixth segment of the liver and a suspicious change in the head of the pancreas. ELISA Em 2 plus test was positive, Western Blot method - the P-5 pattern showed an image that is characteristic of an EM infection. The sixth liver segment with a tumour and a tumour from the head of pancreas were excised by means of laparotomy. On the 6th day after the surgery the patient was discharged from hospital without complications and in good condition. Currently, he is under the control of a parasitic and zoonotic clinic. He takes an 800 mg daily dosage of Albendazole. CONCLUSIONS: The presented clinical case shows that if we have a patient with cystic / tumour change in the pancreas and positive immunological tests, CT and MRI of the abdominal cavity are usually sufficient in order to fully diagnose and to qualify such a person for surgery. The most effective treatment is surgical treatment supplemented with pre- and postsurgical treatment with Albendazole.

Does kisspeptin participate in GABA-mediated modulation of GnRH and GnRH receptor biosynthesis in the hypothalamic-pituitary unit of follicular-phase ewes?

BACKGROUND: The inverse relationship between GnRH transcript level and GABA neurons activity has suggested that GABA at the hypothalamic level may exert a suppressive effect on subsequent steps of the GnRH biosynthesis. In the present study, we analyzed the effects of GABA type A receptor agonist (muscimol) or antagonist (bicuculline) on molecular mechanisms governing GnRH/LH secretion in follicular-phase sheep. METHODS: ELISA technique was used to investigate the effects of muscimol and/or bicuculline on levels of post-translational products of genes encoding GnRH ligand and GnRH receptor (GnRHR) in the preoptic area (POA), anterior (AH) and ventromedial (VMH) hypothalamus, stalk/median eminence (SME), and GnRHR in the anterior pituitary (AP). Real-time PCR was chosen for determination of the effect of drugs on kisspeptin (Kiss 1) mRNA level in POA and VMH including arcuate nucleus (VMH/ARC), and on Kiss1 receptor (Kiss1r) mRNA abundance in POA-hypothalamic structures. These analyses were supplemented by RIA method for measurement of plasma LH concentration. RESULTS: The study demonstrated that muscimol and bicuculline significantly decreased or increased GnRH biosynthesis in all analyzed structures, respectively, and led to analogous changes in plasma LH concentration. Similar muscimol- and bicuculline-related alterations were observed in levels of GnRHR. However, the expression of Kiss 1 and Kiss1r mRNAs in selected POA-hypothalamic areas of either muscimol- and bicuculline-treated animals remained unaltered. CONCLUSIONS: Our data suggest that GABAergic neurotransmission is involved in the regulatory pathways of GnRH/GnRHR biosynthesis and then GnRH/LH release in follicular-phase sheep conceivably via indirect mechanisms that exclude involvement of Kiss 1 neurons.

Analysis of Postoperative Complications After 303 Sentinel Lymph Node Identification Procedures Using the SentiMag® Method in Breast Cancer Patients.

BACKGROUND The objective of this paper was to assess the complications following sentinel lymph node biopsy (SLNB) in breast cancer patients using the SentiMag® method. MATERIAL AND METHODS The study material consisted of 368 patients who had received the SLNB procedure in combination with wide local excision (WLE), simple mastectomy or who had an autonomous SLNB procedure in the period from January 2014 to September 2017. The final study group consisted of 303 patients who attended follow-up consultations. RESULTS Sensory disturbances in the arm occurred in 12 patients (9.9%), including 3 patients (1.5%) after WLE and 9 patients (8.4%) after simple mastectomy. Restricted mobility in the upper limb was experienced by 9 patients (7.1%), including 3 patients (1.5%) after WLE and 6 patients (5.6%) after simple mastectomy. Minimal-degree lymphedema developed in 9 patients (7.5%), including 2 patients (1%) after WLE and 7 patients (6.5%) after simple mastectomy. A significant correlation was demonstrated between the incidence of these complications and the number of lymph nodes dissected. A significantly higher incidence of paresthesia and lymphedema was revealed for simple mastectomy with SLNB when compared to WLE with SLNB. Discolorations upon tracer administration were observed in 47 patients (15.5%). CONCLUSIONS SentiMag® is a safe sentinel lymph node identification method used in breast cancer and has a low risk of complications. The rate of complications increases together with the number of dissected lymph nodes and the extent of the surgery. The possibility of temporary discolorations on the skin should be communicated to the patients explicitly prior to surgery.

Primarily resectable pancreatic adenocarcinoma - to operate or to refer the patient to an oncologist?

The aim of this work is to investigate the optimal therapeutic sequence of resectable pancreatic cancer - primary surgery with adjuvant therapy or neoadjuvant followed by resection. Application of the neoadjuvant approach in routine treatment of pancreatic cancer is rapidly growing every year, despite the lack of final results from randomized trials. Recent advancements in the adjuvant therapy, due to the more effective chemotherapy regimens, favor the upfront surgery strategy. On the other hand, theoretical background and metaanalyses favor the neoadjuvant strategy. Currently, primary resection with adjuvant chemotherapy remains the standard approach in resectable pancreatic cancer, but the first recommendations considering the neoadjuvant approach as an option seem to arise among the scientific societies with a global impact. Preliminary results of Prodige 24 study and PREOPANC-1 trial demonstrates that both options are worth further evaluation in clinical trials. Their results should soon provide more answers to this important clinical questions.

Occurrence of colorectal aberrant crypt foci depending on age and dietary patterns of patients.

BACKGROUND: Aberrant crypt foci (ACF) are commonly considered the early pre-cancerous lesions that can progress to colorectal cancer (CRC). The available literature data reveal that age, dietary factors and lifestyle can affect the development of several dozen percentages of malignant tumours, including CRC. In the present study, an attempt was made to assess the incidence and growth dynamics of ACF and to determine whether the type of diet affected the development and number of AFC. METHODS: Colonoscopy combined with rectal mucosa staining with 0.25% methylene blue was performed in 131 patients. On the day of examination, each patient completed a questionnaire regarding epidemiological data. According to their numbers, colorectal ACF were divided into three groups. The findings were analysed statistically. The Student's t test and the U test were applied in order to determine the significance of differences of means and frequency of events in both groups. Statistica 7.1 and Excel 2010 were used. RESULTS: The single ACF occur in the youngest individuals (ACF < 5). Since the age of 38 years, the number of ACF gradually increases to show a decreasing tendency since the age of 60 years. The number of 5 < ACF < 10 occurs slightly later, since the age of 50 years, and dynamically increases reaching the maximum at the age of 62 years, subsequently the increase is proportional. ACF > 10 occur at a more advanced age (55 years) and their number gradually increases with age. The maximum number is observed at the age of 77 years. In individuals not using high-fibre diets and with high intake of red meat, the probability of higher numbers of ACF increases. The probability of higher numbers of ACF (5 < ACF10) was observed in patients with colon diverticula. In patients with higher BMI, the number of ACF is higher. CONCLUSION: Age significantly affects the number of colorectal ACF. The types of foods consumed can considerably increase the risk of colorectal ACF, which is particularly visible in individuals who do not regularly use high-fibre diets, those obese and with colon diverticula.

Chromoendoscopy with a Standard-Resolution Colonoscope for Evaluation of Rectal Aberrant Crypt Foci.

Colorectal cancer (CRC) is the second most common cause of death worldwide. According to the theory by Vogelstein, colorectal carcinogenesis involves a series of successive changes in the normal colonic mucosa, starting with excessive proliferation and focal disorders of intestinal crypts, followed by adenoma and its subsequent malignant transformation. The first identifiable changes in CRC carcinogenesis are aberrant crypt foci (ACF). ACF are invisible during routine colonoscopy yet are well identifiable in chromoendoscopy using methylene blue or indigo carmine. High-resolution colonoscopes are used for assessment of ACF. The aim of the present study was to evaluate the usefulness of standard-resolution colonoscopy for identification of rectal ACF. The following parameters were evaluated: duration of chromoendoscopy of a given rectal segment, type of ACF, sensitivity and specificity of endoscopy combined with histopathological evaluation. The mean duration of colonoscopy and chromoendoscopy was 26.8 min. In the study population, typical ACF were found in 73 patients (p = 0.489), hyperplastic ACF in 49 (p = 0.328), and dysplastic ACF in 16 patients (p = 0.107). Mixed ACF were observed in 11 individuals (p = 0.073). The sensitivity of the method was found to be 0.96 whereas its specificity 0.99. Identification of rectal ACF using standard-resolution colonoscopy combined with rectal mucosa staining with 0.25% methylene blue is characterised by high sensitivity and specificity.

The outcomes of SILS cholecystectomy in comparison with classic four-trocar laparoscopic cholecystectomy.

INTRODUCTION: General approval of laparoscopy as well as persistent urge to minimize operative trauma with still existing difficulties in putting natural orifice transluminal endoscopic surgery (NOTES) into practice have contributed to the introduction of laparoscopic operations through one incision in the umbilicus named single incision laparoscopic surgery (SILS). AIM: The main aim of this study was to assess the benefits to patients of applying SILS cholecystectomy as a method of gallbladder removal based on the comparison with classic four-port laparoscopic cholecystectomy. MATERIAL AND METHODS: Between 18.03.2009 and 09.12.2009, 100 patients were included in the study and they underwent elective gallbladder removal by applying the laparoscopic technique. All patients were divided into two equal groups: qualified for SILS cholecystectomy (group I) and qualified for classic four-trocar laparoscopic cholecystectomy (group II), whose ASA physical status was I and II. BMI was limited to 35 kg/m(2). Outcome measures included operative time, intensity of postoperative pain and consumption of painkillers, hospital stay, need for conversion, complications, and cosmetic effects. RESULTS: Mean operating time in group I was 66 min and in group II 47.2 min. Intensity of pain evaluated by using the visual analogue scale (VAS) 6 h after the operation in group I was 3.49 and in group II 4.53, whereas 24 h after the operation in group I it was 1.18 and in group II 1.55. The painkiller requirement in group I was smaller than in group II. Mean hospital stay after the operation in group I was 1.33 days and in group II 1.96 days. There were 4 conversions in group I and one conversion in group II. Among the complications in group I there were noted 2 cases of right pneumothorax, 1 case of choleperitonitis and 4 complications connected with wound healing. There was one injury of the duodenum and one wound infection in group II. CONCLUSIONS: Single-incision laparoscopic surgery cholecystectomy can be an alternative to classic laparoscopic cholecystectomy, especially with reference to young people with body mass index less than 35 kg/m(2), without serious systemic diseases, operated on electively due to benign gallbladder diseases.

The place of subfascial endoscopic perforator vein surgery (SEPS) in advanced chronic venous insufficiency treatment.

In spite of medical science development and initiation of new technologies in minimally invasive surgery, treatment of advanced chronic venous insufficiency at the 5(th) and 6(th) degree of CEAP classification is still a great clinical challenge. In case of no satisfactory results of non-surgical treatment of recurrent venous ulcers, scientists search for alternative therapeutic methods which could be more effective and lasting. Subfascial endoscopic perforator vein surgery (SEPS) as a method of reducing venous pressure in the superficial venous system could provide healing of the recurrent venous ulcer. In this study we present a review of contemporary opinions about the place and significance of subfascial endoscopic perforator vein surgery as a treatment of advanced chronic venous insufficiency.

[Program for early detection of ovarian cancer for women as prophylaxis provided at a municipal hospital]. / Program wczesnego rozpoznawania chorób nowotworowych u kobiet jako przyklad dzialan profilaktycznych na poziomie osrodka II stopnia referencyjnosci.

Neoplasms are still severe social problem; they are one of the most common causes of death (30-40%), they last for a very long time and the symptoms are characterized by significant intensity. There have been many attempts of introducing an effective screening program for early detection of ovarian cancer. This paper describes one of them, taking place in municipal hospital. To create and introduce a complex prophylactic program considering early diagnosis of ovarian cancer (with use of Doppler transvaginal sonography and serologic markers--CA125); to assess the value of various features (TVS, CA125 levels, family history) for sensitivity and specificity of screening method; to assess the effectiveness of Doppler TVS as a screening method; and to describe the group of participants that is of the best benefit in screening program. From October 1997 to December 2000 the Program for Early Detection of Ovarian Cancer, introduced by Foundation "Godula HOPE", gathered 3775 women aged 46 +/- 9.5. Most of the participants were self-referred, but there was the group of doctor-referred patients. Bimanual pelvic examination and Doppler TVS were performed in all participants; in case of doubtful results of TVS--serum CA 125 was obtained. The form created by author was used to gather the most important information of medical and family history. The most of participating women were: above 45 yr. old, married, on middle education level, non-working or mental worker, living in town. 365 adnexal tumors were detected among examined women. Using our own criteria 228 patients were chosen to laparotomy--16 of operated tumors were histologically confirmed to be malignant. Our sensitivity of PI was 93.75%, specificity--89.62%. The values for RI were respectively: 89.61% and 73.72%. Program of early detection of ovarian cancer using transvaginal sonography can be organized in municipal hospital; the most important feature of the examination (for screening program) is the grayscale sonographic morphology and the Doppler parameters are of additional value. The best cut-off values of PI and RI were 0.8 and 0.5 respectively. The great meaning of family history of ovarian cancer was confirmed. Demographic results suggest that program should be modified to be available for older patients on low level of education with family history of ovarian or breast cancer.

[Virtual colonography in CT and MRI examinations]. / Wirtualna kolonoskopia w badaniach TK i MR.

The paper presents new ways of visualizing internal structures of the large intestine. Use of spiral computed tomography (CT) or magnetic resonance imaging (MRI) combined with appropriate software leads to imaging that can be compared with colonoscopy or double contrast enema. The authors discuss patients' preparation, methods for CT and MRI variants, indications, advantages and costs.