Placement of self-expanding metal stents is an effective and safe definitive procedure in the palliation of malignant colorectal obstruction. In operable patients, it provides a useful option to avoid colostomy, by facilitating safer single-stage surgery.

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MR imaging is useful in identifying the extent and location of dermatofibrosarcoma protuberans. Although most cases of this tumor are superficial and well defined, we have shown three cases in which the tumor was in a deep location and one case in which the tumor was ill defined in appearance. Knowledge of the variable MR imaging appearances of these tumors may aid in the diagnosis of difficult or atypical cases.

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Computed tomography (CT) can provide essential anatomic and physiologic information required to determine management of intraabdominal and retroperitoneal injuries sustained during blunt abdominal trauma. It can help in evaluation of the type and severity of parenchymal injury, the extent of perirenal hemorrhage and parenchymal devascularization, and the presence of urinary extravasation. CT can help confirm the presence of major injuries to the vascular pedicle and depict occult renal pathologic conditions. Principal indications for the use of CT in the evaluation of blunt renal trauma include (a) the presence of gross hematuria, (b) microscopic hematuria associated with shock (systolic blood pressure <90 mm Hg), and (c) microscopic hematuria associated with a positive result of diagnostic peritoneal lavage. The majority of renal injuries sustained during blunt abdominal trauma are contusions and minor parenchymal lacerations amenable to nonoperative management. Deep parenchymal lacerations, urinary extravasation, and mild to moderate degrees of parenchymal devascularization may also be treated conservatively. Radiologists should look for coexisting renal lesions such as tumors and traumatic false aneurysms that may alter management.

Transitional cell carcinoma (TCC) accounts for up to 10% of neoplasms of the upper urinary tract and usually manifests as hematuria. Imaging plays an important role in assessment of upper tract disease, unlike in bladder TCC, diagnosis of which is usually made at cystoscopy. Traditional imaging modalities, such as excretory urography, retrograde pyelography, and ultrasonography, still play pivotal roles in diagnosis of upper tract TCC, in combination with endourologic techniques. The multicentric nature of TCC makes assessment of the entire urothelium essential before treatment. The advent of minimally invasive surgery, which allows renal preservation in selected patients, makes accurate tumor staging mandatory to determine the appropriate therapy; staging is usually performed with computed tomography (CT) or magnetic resonance (MR) imaging. Vigilant urologic and radiologic follow-up is warranted to assess for metachronous lesions and recurrence. The emerging technique of CT urography allows detection of urinary tract tumors and calculi, assessment of perirenal tissues, and staging of lesions; it may offer the opportunity for one-stop evaluation in the initial assessment of hematuria and in follow-up of TCC. Similar MR imaging protocols can be used in patients who are not candidates for CT urography, although detection of urinary tract calcifications may be suboptimal.

The diagnosis of urinary tract infection (UTI) in the adult is primarily based on typical patient symptomatology and urinary evaluation for the presence of bacteria and white blood cells. Uncomplicated UTI usually does not require radiological evaluation unless it is recurrent. Imaging should, in general, be reserved for those patients in whom conventional treatment has failed or those who have recurrent or unusually severe symptoms. Patients with conditions predisposing to infection, or complications thereof, such as diabetes mellitus or immunocompromised states, may also benefit from early imaging. If pyonephrosis is suspected, early imaging and possible urgent drainage is also warranted. Intravenous urogram and ultrasound have traditionally been used in the assessment of these patients, allowing detection of calculi, obstruction and incomplete bladder emptying. These imaging techniques, while useful, have limitations in the evaluation of renal inflammation and infection in the adult. Computerised tomography has now become accepted as a more sensitive modality for diagnosis and follow-up of complicated renal tract infection. Contrast-enhanced CT allows different phases of excretion to be studied and can define extent of disease and identify significant complications or obstruction. Nuclear medicine has a limited role in the evaluation of urinary tract infection in adults. Its main role is in the assessment of renal function, often prior to surgery. Magnetic resonance imaging has a limited but increasing role. It is particularly useful in those with iodinated contrast allergies, offering an ionising radiation free alternative in the diagnosis of both medical and surgical diseases of the kidney.

Obesity is a chronic disease that is now a global epidemic. The numbers of obese people are exponentially rising in Europe, and it is projected that in Europe by 2010 there will be 150 million obese people. The obesity-related health crisis does not only affect adults, with one in four European children now overweight. Radiologists, both adult and paediatric, need to be aware of the magnitude of the problem, and obese patients cannot be denied radiologic evaluation due to their size. Missed diagnosis, appointment cancellation and embarrassing situations for patients when they are referred for a radiological examination for which they are not suitable are all issues that can be avoided if careful provision is made to accommodate the needs of the obese patient requiring radiologic evaluation. This paper will discuss the epidemiology of obesity and the role of radiology in the assessment of obesity and disorders of fat metabolism. The limitations obesity poses to current radiological equipment and how the radiologist can optimise imaging in the obese patient will be described. Dose reference levels and dose control are discussed. Examples of how obesity both hinders and helps the radiologist will be illustrated. Techniques and pre-procedural preparation to help the obese patient in the interventional suite are discussed.