Magnetic resonance imaging in the complications of kidney transplantation.

Kidney transplantation is currently the treatment of choice in most patients with end-stage chronic renal failure owing to the excellent results in terms of both graft and patient survival. However, surgical complications are still very frequent. Although urological (stricture, urinary fistulas, vesico-ureteral reflux) and lymphatic complications (lymphocoele) have a high incidence, they only rarely lead to graft loss. By contrast, vascular complications (stenosis, arterial and venous thrombosis, arterio-venous fistulas, pseudoaneurysms) are relatively rare, but potentially serious and may affect graft survival. Finally, medical complications such as acute tubular necrosis (ATN), rejection and de novo neoplasms may also arise in kidney transplantation. The purpose of this pictorial review is to illustrate the increasingly significant contribution of magnetic resonance angiography (MRA) in the management of complications of kidney transplantation, and emphasise how this method should now be considered a mandatory step in the diagnostic workup of selected cases. Moreover, the application and role in this setting of new magnetic resonance imaging (MRI) techniques, such as diffusion-weighted and blood oxygen level-dependent (BOLD) MRI, are also discussed.

Erdheim-Chester disease: clinical and radiological findings.

PURPOSE: The authors retrospectively reviewed six cases of histologically proven Erdheim-Chester disease (ECD) to evaluate organ involvement and clinical and radiological findings. MATERIALS AND METHODS: Through a search of the pathology databases of four Italian hospitals, we identified six men (mean age, 56 years) with a histological diagnosis of ECD. Histology was performed on retroperitoneal or pulmonary biopsy, depending on disease involvement on imaging. Patients underwent plain radiography of the lower limbs and chest, total-body computed tomography (CT) and bone scintigraphy. Magnetic resonance (MR) imaging was performed in two patients to evaluate the lower limbs and in one patient to study the brain, the chest and the abdomen. RESULTS: Clinical manifestations included dyspnoea (n=2), hydronephrosis (n=2) and bone pain (n=1). Bilateral symmetrical osteosclerosis of the metaphyseal and diaphyseal portions of the lower-limb long bones was present in five patients. Imaging studies revealed extraskeletal manifestations in all patients, including involvement of the retroperitoneal space (n=4), the lung (n=4) and the heart (n=2). CONCLUSIONS: ECD is a multiorgan disease that displays constant involvement of the bones and retroperitoneum; in particular, of the perirenal fat. Although the diagnosis of ECD is histological, imaging can raise suspicion and help to establish a presumptive diagnosis.

Advantages of multidetector-row CT with multiplanar reformation in guiding percutaneous lung biopsies.

PURPOSE: This study aimed to assess the usefulness of multiplanar reformations (MPR) during multidetector-row computed tomography (MDCT)-guided percutaneous needle biopsy of lung lesions difficult to access with the guidance of the native axial images alone owing to overlying bony structures, large vessels or pleural fissures. MATERIALS AND METHODS: MDCT-guided transthoracic needle biopsy (TNB) was performed on 84 patients (55 men and 29 women; mean age 65 years) with suspected lung neoplasm by using a spiral MDCT scanner with the simultaneous acquisition of six slices per rotation. We determined the site of entry of the 22-gauge Chiba needle on native axial images and coronal or sagittal MPR images. We took care to ensure the shortest needle path without overlying large vessels, main bronchi, pleural fissures or bony structures; access to the lung parenchyma as perpendicular as possible to the pleural plane; and sampling of highly attenuating areas of noncalcified tissue within the lesion. RESULTS: Diagnostic samples were obtained in 96% of cases. In 73 patients, lesions appeared as a solid noncalcified nodule <2 cm; 11 lesions were mass-like. In 22, the biopsy required MPR guidance owing to overlying ribs (18), fissures (2) or hilar-mediastinal location (2). CONCLUSIONS: MDCT MPR images allowed sampling of pulmonary lesions until now considered unreachable with axial MDCT guidance because of overlying bony structures (ribs, sternum and scapulae) or critical location (hilar-mediastinal, proximity to the heart or large vessels). Compared with the conventional procedure, the use of MPR images does not increase the rate of pneumothorax or the procedure time.