Diagnostic potentials -as well as limitations -associated with morphological cross-sectional imaging on the one hand, and functional imaging on the other, are increasingly well understood. It has become obvious that in many cases both kinds of imaging complement one another. So hybrid PET/CT imaging must be considered one of the most promising new developments in medical imaging. The most recently launched line of PET/CT scanners combines high-definition PET with high-end multislice CT. These imaging systems do not only provide a higher diagnostic accuracy based on detection of smaller lesions with CT and PET, but also offer integration of complex CT protocols into the PET/CT scan. Detection of peritoneal carcinomatosis has been challenging with all imaging procedures. A "peritoneal cake" can be detected easily; however, in many cases peritoneal disease will be rather diffuse compromising its detection with cross-sectional imaging techniques. This also applies to FDG-PET/CT where low FDG-uptake in low-grade tumours and the anatomical resolution of PET may hamper detection of small lesions. Additional contrast-enhanced CT as part of the PET/CT scan may aid lesion detection in this situation. The aim of this talk is to give an overview concerning PET/CT in detection of peritoneal carcinomatosis. The specific advantages of US over CT are that US has an image definition in the close range which is much higher. US is more interactive: patient's history as well as painful area or palpable mass can be correlated with the US findings. US shows peristalsis, pulsations and blood flow. US shows the effects of respiration, Valsalva manoeuvre, gravity and compression with the probe, allowing to assess whether organs as bowel and gallbladder are soft or rigid. US allows easy puncture of intraperitoneal fluid and drainage of pus. US in acute abdomen is performed with graded compression. Compression is necessary to displace or compress bowel, eliminating the disturbing influence of bowel gas and to approach the pathological structure closely. This allows using a high-frequency transducer with a better image quality. The compression should be graded to avoid unnecessary pain and to avoid pushing organs out of the US plane. US examination should be symptom-directed and requires communication with the patient. In patients with an acute abdomen the entire abdomen should be examined, i.e. from the axilla to the groin. The final US report should be integrated with the clinical findings, laboratory data, CT-scan and possible other radiological examinations. The US images of appendicitis, diverticulitis, intussusceptions, acute biliary, urological and gynaecological conditions, infectious ileocecitis, perforated peptic ulcer, small bowel obstruction, ruptured aneurysm, pancreatitis, Crohn's disease, epiploic appendagitis, omental infarction and perforating malignancy will be demonstrated using illustrative case histories, with emphasis on the specific advantages of US over CT. Multidetector computed tomography (CT) has emerged as the modality of choice for evaluation of patients with most of the traumatic and nontraumatic conditions causing acute abdominal pain. Operator dependency and technical inadequacy secondary to the body habitués or intestinal gas of the patient are not so rare limitations of the ultrasound exam. Although radiation and use of contrast material are the main drawbacks, CT is the fastest imaging modality for scanning patients. Moreover, multidetector CT scanners allow performing multiplanar reformation without loss of image resolution, a technique that has been shown to improve physician confidence in either confirming or excluding the diagnosis of abdominal emergencies. Increased certainty improves treatment planning and can reduce inappropriate utilisation of hospital resources. Also in trauma patients with multiorgan injuries additional post processing techniques, such as maximum intensity projection and volume rendering, multiplanar reformation may also improve identification and characterisation of especially vessel and bone injuries in the same setting. MDCT is the primary imaging technique used in evaluating patients suspected with most common causes of abdominal pain; acute pancreatitis, acute appendicitis, abdominal abscess or renal stone. It has a high sensitivity and specificity and high confidence level to diagnose or rule out the pathology. CT also has an indispensable role to differentiate nonsurgical rare conditions of acute abdominal pain such as epiploic appendages, omental infarct, mesenteric panniculitis or diverticulitis. The most common viral infection of the brain is herpes encephalitis (HSV1). It is a necrotising encephalitis with a mortality rate of more than 50%. On imaging studies lesions will be seen in the "limbic system", i.e. the temporal lobes, hippocampi, insular cortex and cingulate gyrus. They appear as hypodensity on CT, T2-and FLAIR hyperintensity on MRI, possibly with haemorrhagic transformation. Diffusion is restricted in the early phase. Enhancement occurs at a later stage. Human immunodeficiency virus (HIV) infection is a multifocal giant-cell encephalitis eventually leading to a progressive leuco-encephalopathy. On MR atypical focal or diffuse symmetrical signal abnormalities are seen neither with mass-effect nor with enhancement and typically sparing the U-fibres. Spectroscopy can show an increase of myo-inositol. Progressive multifocal leuco-encephalopathy (PML) is due to reactivation of the JC polyomavirus in immunocompromised patients, 10% of which are HIV positive. On MRI "scalloped" multifocal asymmetrical lesions are seen with minimal mass effect and without enhancement. New treatments of HIV, especially highly active antiretroviral therapy (HAART) can lead to a paradoxical worsening of patients due to the immune reconstitution inflammatory syndrome (IRIS). On MRI mass lesions are seen with diffuse patchy enhancement. Cerebral toxoplamosis appears as multiple enhancing lesions with marked perilesional oedema. Calcification is possible. Prion diseases are caused by a proteinaceous infectious particle leading to Creutzfeld-Jacob disease in humans. Diffusion weighted MR images show high signal intensities in the cortex and the basal ganglia. Abnormalities on T2-weighted images and FLAIR occur at a later stage where atrophy is mostly prominent. Adrenal tumours are a wide group of masses where imaging plays an important role in diagnosis. Most of them are incidental findings during radiological CT or MRI studies, performed for oncological or non-oncological indications. A list of all possibilities will be presented with special consideration on the embryological origin of the tumours. A rationale for technical protocols in CT and MRI is presented in particular to apply to clinical settings. The differential diagnosis between adenoma and mets is the more frequent dilemma in oncologic patients. In non-neoplastic cases the tool is to distinguish between functioning and non-functioning masses, with all the endocrinological implications. More rarely, larger lesions may represent the diagnostic challenge for radiology: to recognise benign and malignant findings is crucial to orient towards different histotypes. Relations with neighbouring structures are also necessary to correctly stage the disease. CT and MRI have some potential diagnostic possibilities to be utilised in the characterisation attempt: density, enhancement, de-enhancement, variations of signal intensity, in particular in FS and IN-OUT of false sequences. Particular considerations will be given to some particular tumours as angioma, myelolipoma, adrenal carcinoma and collision tumours.