Search

Purpose: To compare the diagnostic accuracy of MR cholangiopancreatography (MRCP) and endoscopic retrograde cholangiopancreatography (ERCP) in the diagnosis of malignant stenosis of the distal common bile duct., Materials and Methods: Twenty-one patients (12 males and 9 females, mean age 62 years) with a clinical suspicion of malignancy of the distal biliary tract and pancreatic head underwent tomographic RM evaluation and diagnostic MRCP, followed by diagnostic and, where possible, therapeutic ERCP. The images obtained with ERCP and MRCP were reviewed blind by two experts who evaluated the presence, site, signal features and locoregional extension of the tumours. Histology performed by brushing or biopsy during ERCP and after surgical resection provided the standard of reference for all 21 patients., Results: CPRM correctly identified the presence and site of the distal biliary stenosis in 21/21 (100%) cases, as well as allowing evaluation of the upper abdomen by associating it with conventional MRI. ERCP, instead, allowed detection of the presence and site of biliary stenosis in 20/21 (95%) cases., Discussion and Conclusions: ERCP may have some limitations as regards identification of distal bile duct stenosis in cases of critical stenosis. The non-invasive nature and panoramic capabilities of MRCP and the fact that no contrast material is needed make MRCP the examination of reference in the diagnosis of malignant stenosis of the distal bile duct, also thanks to its ability to visualise the entire biliary tree in the presence of critical strictures of the common bile duct. The rationale for the use of ERCP lies in the possibility of taking histological samples and performing minimally invasive surgical interventions.

Purpose: To compare the potentials of AMI-25 (Endoren) to those of Gadolinium with the dynamic contrast-enhanced technique in the differential diagnosis of focal liver lesions., Material and Methods: Forty patients with at least one focal liver lesion diagnosed at US underwent MRI. We used a 1.5 T unit and employed single-shot half-Fourier T2-weighted FSE and spoiled gradient-echo T1-weighted sequences before and after Gadolinium injection. Multiple acquisitions were obtained during the arterial, portal and delayed phases. Twenty-four to 48 hours later T2*-weighted GRE and SPGR/90 degrees sequences were obtained after AMI-25 administration. In the characterization of solid lesions the gold standard was biopsy performed with a shearing needle; for the diagnosis of angiomas and of 11 metastatic lesions we considered follow-up and clinical data as important diagnostic elements., Results: We found 12 hepatocarcinomas, 14 metastases, 4 cases of focal nodular hyperplasia (FNH), 4 adenomas and 6 angiomas. The diagnosis was correct and confirmed by the conventional examination in all cases but 2 adenomatous lesions and 2 angiomas. Precontrast studies showed slight hyperintensity in 2 of 4 cases of FNH, while the other 2 lesions appeared isointense and were therefore detected only on postcontrast images, where there was contrast agent uptake during the arterial phase and rapid washout. We found only one central scar hyperintense on T2- and hypointense on T1-weighted images. After AMI-25 administration all lesions appeared isointense to surrounding parenchyma on T2* GRE sequences. Adenomas were isointense in the precontrast phase and postcontrast 3 of them showed strong Gadolinium uptake and rapid washout. After AMI-25 two of the 4 lesions were hyperintense while the other two were isointense to the parenchyma. Four of 6 angiomas exhibited a typical pattern characterized by signal hyperintensity on T2-weighted sequences and on AMI-25-enhanced T1- and T2-weighted sequences. Two angiomas were supposed to be of malignant nature but histology showed the presence of a strong fibrotic component. Hepatocarcinomas could be detected on precontrast images. After Gadolinium administration 10 lesions appeared hyperintense in the arterial phase and 2 were hypointense. After AMI-25 all lesions exhibited homogeneous signal hyperintensity and appeared slightly bigger than on Gadolinium-enhanced images. The metastases were only partly demonstrated by MRI. Postgadolinium studies showed 13 lesions with hyperintense signal in the portal phase. AMI-25 administration detected 14 lesions that appeared slightly bigger than on Gadolinium-enhanced images., Conclusions: AMI-25 can help also in characterizing primary lesions with an atypical signal pattern after contrast agent administration thanks to its intrinsic capability of accumulating in benign lesions. However it remains difficult to characterize well differentiated hepatocarcinomas and adenomas. Finally, AMI-25 improves MR capabilities in detecting secondary lesions and possible satellite nodules.

Purpose: To investigate the potentials of 3D breath-hold contrast-enhanced Magnetic Resonance Angiography (MRA) in the diagnosis, follow-up and treatment planning of abdominal aortic aneurysms., Material and Methods: Twenty-four patients with infrarenal aortic aneurysm underwent MRA. We used a 1.5 T unit (GE Horizon, Echospeed 8.2), a phased array surface coil and 3D Fast SPGR T1-weighted sequences acquired on the coronal plane during patient breath-hold and after contrast agent i.v. administration. A bolus-test was done before angiography to optimize imaging delay time. After 3D MRA a Fast-SPGR T1-weighted sequence was acquired on the axial plane. The 3D MRA source images were processed with the MIP algorithm. Qualitative and quantitative analyses were carried out. Helical CT was performed in 6 cases and DSA in 7 cases. Surgery was the reference standard in 15 patients., Results: MRA depicted aneurysm thrombosis in 22 cases, carrefour involvement in 18 cases and iliac arteries involvement in 3 cases. Accessory renal arteries were shown in 4 cases; iliac artery stenosis was associated in 5 cases. There was agreement between MR and Helical CT and DSA findings: surgery confirmed MRA results in 15/15 cases., Conclusions: 3D contrast-enhanced MRA can be considered the method of choice in the follow-up and treatment planning of abdominal aortic aneurysms, because it provides both angiographic and tomographic images: this allows to obtain more information, noninvasively and without the use of ionizing radiations.

Introduction: We investigated the diagnostic accuracy of gadolinium-enhanced 3D MRA in the assessment of thoracic aortic diseases., Material and Methods: Thirty-eight patients with diagnosed or suspected conditions of thoracic aorta were examined with contrast-enhanced MRA. All the examinations were performed with a 1.5 T superconductive magnet acquiring breath-hold 3D fast Gradient-Echo (GE) sequences (TR = 5.9 ms; TE = 1.2 ms; FA = 45 degrees; FOV = 48 cm; thickness = 2-2.5 mm; locs = 30-32; TA = 22-24 s; MA = 512) on the coronal plane. The contrast agent was injected bolus after a bolus-test to evaluate circulation time., Results: Three-dimensional gadolinium-enhanced MRA permitted to correctly diagnose aneurysm in 18 patients, dissection in 13 patients and coarctation in 3 patients. In the former the size and extent of the aneurysmal lumen and its relationship to aortic side branches was demonstrated. As for dissections we evaluated the following parameters: 1) type; 2) presence of intimal flap; 3) thrombosis of the false lumen; 4) dilatation of the aorta; 5) assessment of great vessel origins. MRA data were correlated with those of biplane transesophageal esophageal echocardiography, conventional MRI and spiral CT. In the three patients with aortic coarctation the site of coarctation was correctly identified, the degree of aortic narrowing evaluated and the collateral vessels demonstrated., Conclusions: In our opinion contrast-enhanced three-dimensional MR angiography should be the screening technique of choice in the evaluation of thoracic aorta thanks to its low invasiveness, short acquisition time, large field of view and morphologic resolution. ECG gating is not needed. Limitations are found in the study of wall and periaortic region which are better evaluated with conventional MR imaging.

Introduction: We investigated the efficacy of superparamagnetic iron oxide (SPIO) in the characterization of focal liver lesions on MR images by means of quantitative and qualitative analysis., Material and Methods: We examined 60 patients with at least one focal liver lesion on US images. Conventional T1-weighted spin echo (CSE), proton density and T2-weighted MR images were acquired before and after the injection of a SPIO agent (Endorem, slow infusion, 15 micromoles Fe/kg body weight). A qualitative and a quantitative analysis were performed calculating the contrast enhancement rate in different kinds of lesions; the differences were related to the type of sequence statistically using Student's t-test for coupled samples., Results: Excellent correlation was found with biopsy findings in all but two patients who were false positive for hepatocellular carcinoma (scar on cirrhotic liver). T1-weighted sequences after AMI-25 injection were the most specific ones in hemangioma characterization; PD were the most sensitive sequences in the detection and characterization of liver metastases. T2-weighted sequences were helpful only in the detection of focal liver lesions but they were not specific., Conclusions: In conclusion, SPIO-enhanced MRI is an excellent imaging tool for the differential diagnosis of focal liver lesions, with a good specificity for the differential diagnosis of hemangioma and metastasis. It is also helpful to distinguish benign from malignant lesions.

We discuss the role of imaging techniques in examining the athletes with sports injuries involving the pelvis and the hip. Pelvis and hip pain is of difficult clinical clarification because of the various athletic injuries which may affect the bone or soft tissues at different anatomic sites. Moreover, the symptoms of pelvis and hip injuries are similar in most cases and they are often diffuse and atypical. Diagnostic imaging can play an essential role because treatment success depends on a correct diagnosis and these techniques can actually differentiate the most frequent causes of pelvis and hip sports injuries such as groin strain, osteitis pubis, ischial intersection syndrome, snapping hip, stress fractures, hernias and avulsion fractures. Finally, we discuss the role of magnetic resonance imaging in detecting the causes of hip pain other than sports injuries, such as avascular necrosis, reflex sympathetic dystrophy syndrome, herniation pit, acetabular labrum injuries. To conclude, diagnostic imaging techniques currently permit the direct and noninvasive depiction of pelvis and hip conditions. Particularly, magnetic resonance imaging is very helpful in detecting injury site, extent and characteristics; it can also predict the time period an athlete will be disabled and help define the best treatment planning.

Sixteen patients bearing aneurysms of the abdominal aorta were studied by means of a 0.5 T MR unit. Spin-echo T1-weighted sequences and gradient-echo refocusing sequences were performed. All patients were previously submitted to US; in 8 cases angio CT was performed, and in 6 patients angiography of the abdominal aorta. A comparative analysis with the US findings showed a high correlation coefficient for the maximum diameters (R = 0.93) while site and size evaluations were not accurate. A very high correlation coefficient for the maximum diameters (0.97) was found at the comparative analysis with CT findings, while in two cases an erroneous suprarenal location was described. Angiographic examination provided valuable information about renal and iliac involvement, but the maximum diameters could not be accurately assessed. Spin-echo MRI allowed good evaluation of the maximum size, of location and extent of the aneurysm, as well as of iliac involvement; this technique, however, was useless in the characterization of the thrombus. Gradient-echo refocusing sequences have proven very useful for the identification of endoluminal contours and for the correct evaluation of the thrombus. Spin-echo sequences, on the contrary, accurately assessed only 7 cases, whereas the diagnosis was uncertain in the remaining 4 patients.