Traumatic renal artery dissection: from imaging to management.

Injury to the renal artery following blunt trauma is detected increasingly due to widespread and early use of multidetector computed tomography (CT), but optimal treatment remains controversial as no guidelines are available. This review illustrates the spectrum of imaging findings of traumatic renal artery dissection based on our experience, with the aim of understanding the physiopathology of ischaemic damage to the kidney, and the process of choosing the best therapeutic strategy (conservative, endovascular, surgical). Five main patterns of traumatic renal artery dissection are described: avulsion of renal hilum; dissection of the segmental renal branches; preocclusive main renal artery dissection; renal artery stenosis without flow limitation; thrombogenic renal artery intimal tear. In the polytrauma patient, management depends on various factors (haemodynamic status, associated lesions, time of diagnosis) rather than on the degree of renal artery stenosis. Non-operative management (NOM) is the preferred option in case of non-flow-limiting dissection of the renal artery and angio-embolisation is an important adjunct to NOM in cases of active bleeding. Embolisation of the renal artery stump may be the best option in cases of occlusive dissection, as catheter manipulation carries a high risk of vessel rupture. The therapeutic window for kidney revascularisation in cases of flow-limiting dissection of main renal artery may be variable. Endovascular stenting >4 h after trauma should be performed only if residual flow with preserved parenchymal perfusion is detected at angiography. Antiplatelet therapy administration is recommended in cases of stenting, but conditioned by the bleeding risk of the patient.

[Diagnosis of large-vessel vasculitis using [18F]-FDG PET-CT]. / Diagnosi di vasculite dei grandi vasi con (18)F-FDG PET-TC.

PURPOSE: The aim of this retrospective study was to assess the performance of fluorine-18 fluorodeoxyglucose positron emission tomography-computed tomography ([(18)F]-FDG PET-CT) for diagnosing large-vessel vasculitis (LVV) for a subset of patients at increased risk of rheumatic/immune diseases, taking into account concurrent immunosuppressive therapy. MATERIALS AND METHODS: The study comprised 64 rheumatological referrals with suspected LVV; half of the patients were on immunosuppressive therapy at the time of examination. The final diagnosis of LVV was established in 31 patients. To evaluate vascular uptake, the nuclear medicine physician employed both a semiquantitative method based on standardised uptake value (SUV) determination and a qualitative method based on a visual score from 0 to 3 on the maximum intensity projection (MIP) reformats. Finally, a joint assessment was carried out between the nuclear medicine physician and the reporting radiologist, in which PET metabolic data were re-evaluated taking into account clinical data and baseline CT scans. McNemar's test was used to compare four types of analysis: semiquantitative (cutoff ≥ 2.4), qualitative with standard cutoff (grade ≥ 2), qualitative with reduced cutoff (grade ≥ 1) and joint. RESULTS: Semiquantitative analysis (sensitivity 74.19%, specificity 78.78%, accuracy 76.56%) and qualitative analysis with standard cutoff (sensitivity 64.51%, specificity 84.84%, accuracy 75.00%) showed no statistical difference for the diagnosis of LVV, whereas qualitative analysis with lower cutoff (sensitivity 93.54%, specificity 75.75%, accuracy 84.37%) proved to be better than the other two. Joint analysis (sensitivity 93.54%, specificity 93.93%, accuracy 93.75%) introduced some corrective elements not present in the qualitative analysis with cutoff ≥ 1 and therefore increased specificity significantly. CONCLUSIONS: Interpretation of PET-CT should be individualised for each patient by taking into account clinical-radiological and metabolic data. To this end, cooperation between the nuclear medicine specialist and the radiologist is essential.

Paragangliomas in an endemic area: from genetics to morphofunctional imaging. A pictorial essay.

The aim of this pictorial essay is to illustrate the morphological [computed tomography (CT) and magnetic resonance imaging (MRI)], vascular (angiography) and functional (nuclear medicine) features of paragangliomas, uncommon lesions of the head and neck region and even more of the thorax, abdomen and pelvis, arising in an endemic area in northern Italy. These hypervascular, well-circumscribed masses usually have innocuous clinical manifestations as slowly enlarging soft-tissue lesions; however, more rarely, they can cause cranial-nerve palsy, particularly lesions arising near the skull base, or symptoms related to their secreting activity. Most paragangliomas are benign and their prognosis is directly related to the location of the tumour: those arising at the carotid body have the best outcome, whereas those located at the skull base have a less favourable prognosis. Angiography is required preoperatively in larger paragangliomas for surgical planning (vascular mapping) and, rarely, for preoperative embolisation. Morphological and functional imaging is also mandatory for surgical and/or radiometabolic treatment planning and follow-up.

Role of magnetic resonance imaging in the evaluation of diabetic foot with suspected osteomyelitis.

PURPOSE: This study evaluated Magnetic Resonance Imaging (MRI) in infected diabetic foot ulcers. MATERIALS AND METHODS: Sixteen diabetic patients underwent foot MRI between January 2006 and September 2007 for suspected unilateral osteomyelitis. Three of 16 patients showed radiographic changes due to Charcot neuropathic osteoarthropathy. Twelve of 16 patients also underwent MR angiography of the lower limbs for the purpose of planning surgical or endovascular treatment. The musculoskeletal and vascular MRI studies were retrospectively reviewed by three radiologists. RESULTS: The final diagnosis, based on clinical, imaging, microbiological and histological findings, was osteomyelitis in 13/16 cases. Foot MRI allowed a correct diagnosis in 15/16 patients, with 1 false positive result demonstrated by computed tomography (CT)-guided bone biopsy. MR angiography of the lower limbs was considered nondiagnostic in 5/12 patients in the infrapopliteal region owing to venous contamination. CONCLUSIONS: MRI has high sensitivity for the detection of osteomyelitis in the diabetic foot but lower specificity related to Charcot neuropathic osteoarthropathy. If diagnostic uncertainty persists, a bone biopsy is indicated. The inflammatory hyperaemia caused by the ulcer deteriorates the diagnostic quality of 40%-50% of MR angiography studies in the infrapopliteal region. In these cases, selective arteriography is appropriate, as it can be performed in the same session as angioplasty.

CT-guided percutaneous vertebroplasty: personal experience in the treatment of osteoporotic fractures and dorsolumbar metastases.

PURPOSE: This study was performed to evaluate the results and complications of percutaneous vertebroplasty (PVP) performed under CT guidance. MATERIALS AND METHODS: We treated 106 patients (182 PVP): 67 for osteoporotic vertebral compression fracture, and 39 for osteolytic metastases. The first 78 patients were treated using computed tomography (CT) combined with conventional fluoroscopy as an imaging guide (135 PVP). In 28 patients, the procedure was performed with multislice CT fluoroscopy (47 PVP). RESULTS: Partial or complete pain relief was obtained in 98% of patients within 24 h from the treatment; significant results were also obtained with regard to improvement in functional mobility and reduction of analgesic use. CT allowed the detection of cement leakage in 43.9%. Severe complications were one case of pneumothorax and two cases of symptomatic cement leakage. Mild complications included two cases of cement pulmonary embolism. During the follow-up, eight osteoporotic patients presented a new vertebral fracture, and new vertebral metastases appeared in two oncological patients. CONCLUSIONS: Our personal experience confirms the efficacy of PVP treatment for both osteoporotic and oncological patients. The use of CT guidance reduces the risk of complications in comparison with conventional fluoroscopy alone, as well as facilitates the detection of small cement leakages.