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Purpose: To assess the role of magnetic resonance enteroclysis (MRE) in patients with Crohn's disease, in order to identify involved segments, define the extension and evaluate transmural alterations., Materials and Methods: Eighteen patients with known Crohn's disease were studied with MR (1.5 T), with breath-hold T2-weighted TSE, T2-weighted TSE SPIR and 3D T1-weighted sequences before and after gadolinium injection (0.2 mmol/kg) in the coronal and axial planes. The small bowel was distended by the administration of 2 l of methylcellulose through a nasojejunal tube and drug induced hypotony. Typical patterns of Crohn's disease, such as mucosal abnormalities, parietal thickening and narrowing of the bowel, prestenotic dilation, fibrofatty proliferation and enlarged lymph nodes were analysed on radiological and MRE images. MRE was performed within 30 days from conventional radiological studies (conventional enteroclysis and small bowel follow-through)., Results: Good distension of the bowel wall was obtained in all cases. MRE assessed the presence of parietal thickening and narrowing of the bowel wall (14/18 cases) and the presence of prestenotic dilatation (12/18 cases). Vascular enhancement (14/18 cases), transmural abnormalities (8/18 cases), fibrofatty proliferation (3/18 cases), abscess formation (2/18 cases) and enlarged mesenteric lymph nodes (6/18 cases) were also observed. MRE missed small fistulas which were visible in radiological studies in two patients., Conclusions: MRE appears to be a promising technique in patients with Crohn's disease. Due to limited spatial resolution MRE could be a useful adjunct to radiological studies and in following up selected groups of patients with prior known disease.

Purpose: The incidence of iatrogenic pseudoaneurysms as a complication of angiographic procedures is increasing. The purpose of this study was to test the validity and the efficacy of a new interventional procedure in the treatment of iatrogenic pseudoaneurysms., Material and Methods: Between April 1999 and June 2000, 14 patients suffering from a iatrogenic pseudoaneurysm were treated with the new technique which consists of the direct puncture of the aneurysmal cavity using the Seldinger technique and the introduction of a movable-core Teflon-coated guide wire into the hollow of the sac. Mild external compression with Femostop is then applied for no longer than 120 minutes. The puncture was also performed with colour-Doppler US guidance., Results: We observed the complete healing of the pseudoaneurysms in all of the treated patients with no immediate complications or recurrence in the follow-up period., Discussion and Conclusions: The procedure applied to treat our group of patients proved valid, easy to perform and capable of producing satisfactory, Results: This new interventional method for treating iatrogenic pseudoaneurysms may be considered an effective alternative to surgery and US-guided compression and capable of achieving a quick recovery. The procedure is particularly suitable in those patients that may suffer discomfort or complications from the widely applied technique of sonographically-guided compression of pseudoaneurysms.

Purpose: We compared GRE T1 3D FS sequence with other acquisition techniques available on medium field strength MR units (.5 T) in patellofemoral cartilage studies., Material and Methods: The imaging protocol scheduled Spin Echo (SE), Inversion Recovery (STIR), Gradient Echo (GRE), Turbo Spin Echo (TSE), Turbo-Inversion Recovery (Turbo-STIR), Gradient Spin Echo (GRASE) and Echo Planar (EPI) sequences, in some cases combined with Fat Suppression (FS) or Magnetization Transfer Contrast (MTC) sequences when suitable. In vitro studies were carried out for signal-to-noise ratio (SNR) evaluation, and in vivo on 10 healthy volunteers for contrast-to-noise ratio (CNR) evaluation between cartilage, bone marrow and fluid. The exams were carried out on MR equipment operating at .5 T, with 15 mT/m power gradients., Results: In both in vitro and in vivo studies, GRE T1 3D FS sequences yielded better results in SNR and CNR than other sequences. The GRE T1 3D FS technique combines the advantages of the increased resolution of 3D images with the increased dynamic range of fat suppressed images, for better CNR between cartilage, fluid and bone marrow., Conclusion: GRE T1 3D FS sequences are the MR acquisition technique of choice in the assessment of the hyaline cartilage of the knee, even at medium field strength.

The conventional Spin-Echo sequences have been the most used acquisition techniques on Magnetic Resonance Imaging (MRI) of the brain, since the beginning of 1990s. Recently, however, technological developments proposed such new fast acquisition techniques, with a dramatic reduction in acquisition time as Gradient Echo, Turbo Spin Echo, Gradient Spin Echo ed Echo Planar sequences. We investigated the comparative adequacy of the new fast sequences, in brain MR studies versus conventional sequences, on medium field strength MR equipment (.5 T). On in vitro exams S/N ratio was evaluated and on in vivo study C/N ratio between white substance grey substance and fluid were evaluated, in 15 healthy volunteers. All the exams were carried out on Philips NT5 Gyroscan MR unit operating at .5 T, with 15 mT/m power gradients. Both conventional and fast sequences Spin-Echo (SE), Inversion Recovery (IR), Gradient-Echo (GE), Turbo Spin-Echo (TSE), Gradient Spin-Echo (GRASE) and Echo Planar (EPI), all optimized to obtain T1, T2 and T1-IR weighted images, were performed. The sequences were evaluated separately comparing different acquisition techniques relative to the same type of contrast (T1, T2, and T1-IR). The results indicate the superiority of the fast acquisition techniques, both in terms of quality and acquisition times, except for T1-weighted images, where the conventional Spin-Echo sequences confirmed to be superior. In conclusion, the present study suggests that fast acquisition techniques can improve the conventional protocol of sequences, in the anatomical representation of the normal brain even with medium field strength equipment only on T2 and T1-IR weighted images. On T1-weighted imaging conventional SE acquisition technique is still the best choice. The time saving obtained with fast sequences can therefore be used for an overall improvement in the quality of images, and to apply accessory acquisition plans on routine exams.

Introduction: We report our experience with the superselective embolization of iatrogenic vascular injuries. We used new coaxial catheters and new microcoils to assess their technical features and efficacy., Materials and Methods: Diagnostic angiography by catheterization of the main renal artery was performed in 7 patients with suspected renal vascular injury to detect injury presence and site. After super-selective catheterization of the feeding arteries with a coaxial catheter (Tracker 18), we performed embolization with platinum microcoils inserted using a coil pusher. The procedure efficacy was assessed at angiography and by comparing serum hemoglobin and hematocrit levels before and after embolization; posttreatment renal function was also studied., Results: Selective embolization permitted complete occlusion of the arteries feeding the vascular injury in all patients, preserving as much parenchyma as possible. Hemoglobin and hematocrit levels were improved or unchanged after the maneuver (average hemoglobin level before embolization: 9.01 mg/dl versus 9.95 mg/dl after embolization; average hematocrit level before embolization: 27.3% versus 30.06% after embolization). We had no difficulty during microcoil insertion and the coaxial catheter was always stable., Conclusion: Superselective embolization of iatrogenic vascular injuries is an effective and definitive treatment. We recommend it in the patients with renal bleeding due to iatrogenic vascular injury after percutaneous diagnostic or therapeutic procedures.

We studied the main ocular and retrobulbar vessels with color-Doppler US and report on examination technique, detectability of the vessels and their flow characteristics to define the normal ranges of Doppler spectra for each artery and vein. We comparatively examined both eyes of 20 healthy subjects. Of each eye we studied the ophthalmic artery, the central retinal artery, the ciliary artery, the central retinal vein and the superior ophthalmic vein. The following flow parameters were considered: peak systolic velocity, end-diastolic velocity and resistive index for arteries; maximum and minimum velocity for veins. The examination lasted about 10 minutes per eye--20 minutes for each subject. In all subjects the five investigated vessels were identified in both eyes, and adequate Doppler spectra were obtained. The average peak systolic velocities of ophthalmic, central retinal and ciliary arteries were respectively about 35, 12 and 10 cm/s, with low resistance patterns (resistive index: 0.75, 0.72 and 0.68, respectively). The venous flow, which is usually continuous, may be sometimes influenced by cardiac and respiratory activities: the maximum velocities of superior ophthalmic and central retinal veins were about 6 and 5 cm/s, respectively. Color-Doppler US noninvasively visualizes both ocular and retrobulbar vessels, providing major hemodynamic information from different flow parameters; the knowledge of these parameters in normal conditions can be the basis of hemodynamic studies in many abnormal orbital conditions.

The purpose of this study was to assess Magnetic Resonance Imaging (MRI) patterns of hepatocellular carcinoma (HCC) treated with percutaneous ethanol injection (PEI) or Transarterial Chemoembolization (TACE) and, consequently, the potential role of MR Imaging in the follow-up of these lesions. HCC treated with PEI. Thirty-one patients with a single small HCC lesion underwent MR Imaging at 0.5 T before and after PEI. In all cases before and after treatment contrast enhanced Computed Tomography (CT) and US-guided fine-needle biopsy were performed. Twenty-seven of 31 HCC lesions in which complete tumor necrosis was obtained with PEI showed homogeneous hypointensity on SE T2-weighted MR images. This feature corresponded to an unenhanced and low-attenuation area on follow-up contrast-enhanced CT scans. All these lesions were negative for malignant cells at fine-needle biopsy follow-up. In four HCCs, high-signal areas on SE T2-weighted images and high-attenuation areas on contrast-enhanced CT scans were observed, suggesting the presence of residual tumor tissue; these lesions were positive for malignant cells at 6-month fine-needle biopsy. In each case, incomplete tumor necrosis was confirmed at pathologic examination of the surgical specimen. HCC treated with TACE. Twenty-one patients with a total of 36 HCC lesions underwent plain and Gadolinium-enhanced MR Imaging before and after TACE. 10 HCC lesions were later surgically resected; 26/36 lesions underwent MR, CT and angiographic follow-up. At short-term follow-up exams (15-30 days), hypointensity was present on enhanced SE T1 weighted sequences in those lesions (5/10) in which complete tumor necrosis was histologically confirmed. In the remaining 5/10 HCC lesions, persistent viable tumor portions were found at pathology. These areas corresponded to areas on hyperintensity of Gadolinium-enhanced SE T1-weighted images. Hypointensity on both SE T2-weighted and enhanced SE T1-weighted images was a characteristic pattern on long-term follow-up MR images in 21/26 unresected lesions; this finding was correlated with devascularization at angiography; the presence of hyperintense areas on SE T2 weighted and enhanced SE T1-weighted images corresponded to the persistence of hypervascular (viable) areas at angiography.

This work was aimed at assessing Magnetic Resonance (MR) accuracy in the preoperative investigation of abdominal aortic aneurysms, with a view to suggesting MRI as the method of choice for surgical planning, replacing other relatively invasive investigation techniques like angiography and enhanced CT. In the last 3 years 80 patients with abdominal aortic aneurysms identified with US or CT were examined with 0.5-T MRI and underwent surgical repair within 15 days. Spin-echo (SE) T1-weighted axial, sagittal and coronal sequences were always performed. In 18 patients gradient-echo (GE) flow sequences were also acquired; SE T2-weighted sequences were used to study parietal thrombi in 10 patients and finally Gd-DTPA T1-weighted sequences were obtained in inflammatory aneurysms (3 patients). MR images were blindly evaluated by 2 radiologists. The following variables which are useful for surgical planning were considered for each patient: aneurysm extent, characteristics of parietal thrombi, dissections, fixurations, inflammation signs, involvement of renal arteries, vena cava, ureters, duodenum, the presence of retroaortic renal vein or of other anomalies or associated conditions. MR images were always compared with intraoperative findings, since surgery was considered as the gold standard. MR findings were in agreement with surgical findings in the evaluation of cranio-caudal aneurysm extent (78/80), parietal thrombus features (80/80), dissection (1/1) and fixuration signs (8/9), origin of renal arteries (80/80), inferior vena cava involvement (3/3), other anatomical anomalies or conditions (6/6). Inflammation signs were overestimated (14/8) as well as adhesion between aneurysm and duodenum (17/13). The presence of distal renal polar arteries was underestimated (2/4). In conclusion, MRI proves to be a highly sensitive method to demonstrate abdominal aortic aneurysms and is therefore suggested as the examination of choice before surgery.

Transcatheter arterial chemoembolization (TAE) is generally considered to be an effective palliative treatment in patients with inoperable hepatocellular carcinoma (HCC). Recently, TAE has also been performed on operable cases, in order to reduce the chances of recurrence. This study was aimed at evaluating the histopathologic changes following chemoembolization in surgically resected HCCs. Chemoembolization was performed by selective intra-arterial injection of Lipiodol-chemotherapeutic agent (Adriamycin), followed by terminal embolization with Spongostan, in 5 patients with operable HCC. All patients underwent Computed Tomography (CT) follow-up and subsequent partial hepatectomy. CT after chemoembolization accurately demonstrated no increase in tumor size in all patients. In all HCCs a thick fibrous capsule was found. Histopathology of the surgically resected HCCs demonstrated complete necrosis of the primary tumor in 4/5 cases; 1 HCC remained viable and tumor cells were found in a few daughter nodules surrounding the tumor. In 1 case there were viable tumor emboli in the small portal vessels around the tumor. In patients with resectable HCC, TAE was useful in preventing tumor growth and in thickening the capsule, thus making surgery safer and reducing the chances of recurrence.

For the decompression of the biliary tree in case of obstructive neoplastic jaundice, 62 biliary endoprostheses were placed in 54 patients as an alternative to internal-external drainage. Teflon prostheses were used in 26 patients--which were placed in the stenotic tract--while in 28 patients soft percuflex prostheses were used, whose lower extremity was placed in the duodenum. The mean survival has been 6-7 months, with peaks ranging from 1 month to 2 years. By comparing the results obtained with the two different kinds of prosthesis we found that soft endoprostheses were associated with a lower incidence of late complications than teflon prostheses: cholangitis occurred in 7.2% of cases (vs teflon: 16%), occlusions in 3.5% (vs teflon: 11.5%), migrations in 7.2% (vs teflon: 7.6%). The incidence of such complications was, however, higher a few months after the application of the prosthesis. This palliative treatment is suggested in patients whose expected survival is not longer than 1-6 months. On the contrary, in case of patients with a better prognosis, an internal-external catheter drainage is preferred, for an easier access to the site of the lesion.