[Magnetic resonance in the assessment of critical points of impingement of the shoulder]

Impingement syndrome is caused by a conflictual status between rotator cuff, subacromial bursa and anatomic and functional acro-mioclavicular arch. The clinical signs of this syndrome include pain and functional disability in abduction and extrarotation of the shoulder. This study was aimed at verifying Magnetic Resonance Imaging (MRI) capabilities in showing the critical points of impingement and their incidence. Fifty-four cases of impingement syndrome were studied. The best visualization of functional acromioclavicular arch was obtained using a new study technique. All patients had critical points of impingement. In 65% of cases, acromioclavicular arthritis induced impingement on the supraspinatus tendon and in 35% of cases on the muscle. In 46% of the patients, impingement between coracoacromial ligament, partially thickened in 25% of the cases and totally thickened in 75%, and supraspinatus tendon was observed. In 7% of the whole of shoulders, the acromion had an uncinatus shape. MRI, thanks to its multiplanar imaging, allowed the complete evaluation of the articular structures with complex anatomy. The assessment of different types of impingement points can be considered a valuable approach to the therapeutic stage.

[Malignant occlusion of the bile ducts. Treatment with metallic endoprosthesis: Wallstent vs Strecker's stent]

Stenting is the method of choice to relieve jaundice in the patients with inoperable malignant obstructions of the biliary tree. Over the last fifteen years, thousands of patients have been treated, if endoscopy failed or was unfeasible, with percutaneous transhepatic procedures: despite this wide experience, the role of conventional plastic endoprostheses is still debated, because these devices exhibit major limitations. The main objection to the use of Carey-Coons endoprostheses is the fact that a high rate of early occlusions has always been observed with plastic stents with a wide outer diameter (12-16 F). Metallic stents (self-expandable, Wallstent balloon-expandable Strecker stents) might solve these problems, especially in high-risk patients. The authors report their experience in 50 patients with midterm follow-up, a comparison of the two types of stents and their technical features.

[Technical and methodologic considerations on a new approach to the transjugular intrahepatic portosystemic shunt]

The authors report their experience with 10 transjugular intrahepatic portosystemic shunts (TIPS) in nine patients with severe portal hypertension; indications were rebleeding after sclerosing treatment in 8 cases and unmanageable ascitis in one case. The passage of the needle from the hepatic venous system into the portal venous system during the procedure may be technically difficult with both skin markers and US guidance, and several passages through liver parenchyma may be needed: this step is certainly the most critical one, for maneuver duration--and therefore risks--depend on it. Thus, in the last 6 patients a new method was used to easily identify portal bifurcation: a thin stainless platinum-tip guide-wire (0.018-inch diameter) was inserted, by epigastric approach under US guidance, through a fine Chiba needle (22 G) in the left main portal branch, dramatically reducing the number of failed punctures and maneuver duration. Both the above goals are to be reached to make TIPS easier and therefore advantage both patients and interventional radiologists.

[Intra-osseus hidden fractures of the knee in athletes: assessment with magnetic resonance imaging]

The diagnostic capabilities of Magnetic Resonance Imaging (MRI) were investigated in the study of occult intraosseous fractures of the knees in athletes; this pathologic condition is difficult to assess with conventional diagnostic techniques. Twelve athletes were considered and submitted to MR examinations 1-8 days after trauma. All patients had undergone plain films, 6 of them CT and 3 scintigraphy. Four patients were followed with MRI at 15 and 30 days. Plain films were negative in all patients. On CT, in one case only an area of segmental osteoporosis was identified at the anterolateral tibial plateau. Scintigraphy provided positive but aspecific results in all three patients. MRI demonstrated all lesions: 3 at the tibial plateau, 5 at the lateral femoral condyle and 2 at the medial femoral condyle. Double localizations were observed in two patients, femorotibial and tibiopatellar, respectively. In no case lesions of meniscal and/or capsuloligamentous structures of the knee were associated. Arthroscopy, which was employed in two patients, confirmed MR diagnosis. Thanks to its high spatial and contrast resolution and to its multiplanar capabilities, MRI can be considered the method of choice in the study of occult intraosseous fractures of athletes' knees. Beside localizing the lesion site, MRI allows the evaluation of its extent (linear or reticulo-geographic patterns) and the exclusion of possible involvement of meniscal and/or capsulo-ligamentous structures. MRI follow-up of this condition showed the "restitutio ad integrum" of the medullary trabecular bone as early as at 15 and 30 days, depending on lesion pattern and extent. On the basis of our experience, MRI emerges as the only diagnostic technique allowing the accurate evaluation of occult intraosseous fractures of the knee in athletes, because it provides early and detailed information which is valuable for the therapeutic approach, which is of fundamental importance to resume sports activity quickly.

Basics of the magnetic resonance phenomenon

Magnetic Resonance is increasing its importance as a diagnostic mean. For an effective and accurate MRI practice, new fundamental principles, which are at the basis of this phenomenon, must be acquired. In this chapter an extremely simplified overview of the physical basics of MRI is introduced, to help the readers understand the principles underlying this complex technique. Basic physics, T1 and T2 relaxation times, spin echo sequences, which can be acquired with the now available units, and tissue characteristics are illustrated. For those who are interested in a further and more detailed reading in this field, a bibliography is also quoted.

Lumbar disk herniation: MR imaging assessment of natural history in patients treated without surgery

The aim of this study was to evaluate the evolution of lumbar disk herniation in patients treated without surgery. Sixty-nine patients with a lumbar disk herniation proved at magnetic resonance (MR) imaging underwent a follow-up MR imaging study. The disk herniations evaluated during both MR imaging examinations were measured and classified into four categories according to the change in size that occurred. The patients were also divided into three clinical classes on the basis of the clinical outcome. Sixty-three percent of the patients showed a reduction of disk herniation of more than 30% (48% had a reduction of more than 70%), while only 8% demonstrated worsening of the clinical picture. These findings suggest that lumbar disk herniation may be primarily a medical (nonsurgical) disease and that MR imaging could play an important role in management of and research into the disorder.

Talocalcaneal coalition: computed tomography and magnetic resonance imaging diagnosis

A correct evaluation of site and extension of the talocalcaneal coalition inducing biomechanical ankle alterations is very important for planning therapy. Four male patients were submitted to computed tomography (CT) and three of them were also examined by means of magnetic resonance imaging (MRI). In one patient, studied by CT only, a bilateral talocalcaneal coalition was present, while the other three patients, controlled with CT and MRI, were affected by monolateral talocalcaneal coalition which was of osseous type in one case and fibrocartilaginous in two cases. CT and MRI provided detailed information on type and extension of the coalition and both helped in distinguishing between osseous and fibrocartilaginous forms. Only MRI showed an area of subchondral ischemic disease of the posterior subtalar joint in one patient with monolateral fibrocartilaginous talocalcaneal coalition. Compared with CT, MRI proved to be more accurate in evaluation of the talocalcaneal coalition, due to its wider display capability.

[Magnetic resonance in the staging of multiple myeloma]

The authors retrospectively reviewed the MR examinations of 46 patients with clinical and laboratory findings of monoclonal gammopathies (MG). All cases had been submitted to radiographic examination which had shown skeletal involvement in 22 cases and osteoporosis in 11, with rupture of the vertebral body in 3 patients. Scintigraphy had been performed on all patients and CT on 12; 36 patients were subsequently submitted to follow-up (at 6, 12 and 24 months). MR examinations were performed with dedicated coils and standard sequences for the subjects with skeletal localizations on X-ray images. The extant cases, with no radiographic evidence of skeletal involvement, were submitted to MRI of the spine, skull and pelvis. In agreement with clinical and laboratory findings and with follow-up results (in 36 patients), MRI diagnosed MG with no skeletal involvement in 13 cases, osteoporosis in 8 (with rupture of the vertebral body in 2), asymptomatic non-progressive myeloma in 4, solitary myeloma in 3, and multiple myeloma in 18 cases. The good identification of bone marrow and its multiplanarity make MRI the method of choice in the study of patients with suspected or known gammopathies. If compared with other modalities, MRI is more sensitive and accurate in depicting the tumor, its size and relationship to periskeletal tissues, and its possible multifocality. Moreover, the technique has proven to be a valid tool during the follow-up, showing tumor response to therapy.

Myxoid intraneural cysts of external popliteal ischiadic nerve. Report of 2 cases studied with ultrasound, computed tomography and magnetic resonance imaging

Peripheral neuropathy of the external popliteal ischiadic nerve caused by intraneural cysts is a very rare and peculiar pathological phenomenon compared with diseases associated with extraneural cysts or colliquative phenomena of solid nervous lesions. Two cases of peripheral neuropathy of the external popliteal ischiadic nerve caused by intraneural cysts and evaluated with ultrasound, computed tomography and magnetic resonance are described. The diagnostic efficacy of these imaging modalities is also evaluated with particular reference to MR capability to define the morphology of such lesions and their relationships to the surrounding structures. It is not yet possible to obtain a correct diagnosis about histopathologic features by means of the imaging techniques currently available. Nevertheless, they do provide information about the involvement of the neighboring areas, which are useful indications for possible surgical treatment of the disease.

[Acute instability of the shoulder in athletes. The role of magnetic resonance in therapy planning]

Magnetic resonance imaging (MRI) of the shoulder was performed to evaluate both the actual role of this technique in the study and staging of acute shoulder instability, and its potentials as diagnostic tool, with particular reference to treatment planning. Seventeen athletes with acute shoulder instability were examined. All MRI examinations, subsequent to plain radiographs, were performed within 48 hours from the traumatic event. After MRI examination, 14 patients underwent physiotherapy (2 cases were subsequently submitted to arthrotomy), and only 3 cases underwent surgical treatment in the acute phase (2 arthrotomies and 1 arthroscopy). These cases, submitted to MRI in the acute phase and subsequently to surgery, showed anterior glenoid labrum involvement with good evidence of associated skeletal lesions (Hill-Sachs lesions in 1); changes in the inferior glenohumeral ligament complex (2 cases) were also observed. In the other examined cases, MRI always provided accurate information on the glenoid labra and the anterior capsular mechanism. When the superior glenohumeral ligament was investigated (9 cases of 17), no alterations were observed. Acting as natural contrast, the presence of joint effusion allows good visualization, on T1-weighted sequences, of the structures involved by the traumatic events. Contrast resolution improvement could be obtained by employing gradient-echo T2 weighted sequences, which proved to be quite valuable for a correct depiction of the lesions involving the inferior glenohumeral ligament complex. In conclusion, MRI can be considered as a valuable diagnostic method for the early evaluation of the acute shoulder instability, since it provides information of the utmost importance for the subsequent therapeutical approach.

[Magnetic resonance of the shoulder: technic, anatomy ana clinical results]

MR imaging was employed in 232 patients with traumatic or degenerative lesions of the shoulder. MR diagnosis was compared with arthrotomic findings in 19 cases, and with arthroscopic results in 3 cases. MR technique is here presented and the choice of scanning planes is discussed, together with the sequences of image acquisition and with the features of the surface coil employed. Axial, sagittal, and coronal scans were used in all cases. Both sagittal and coronal planes were performed obliquely on the basis of precise anatomical structures. T1-weighted sequences were used for they are reliable in locating the various anatomical structures and efficient in defining the several different pathologic conditions. The role of T2-weighted sequences was complementary, and they were employed in selected cases only. A surface coil is presented with a particular configuration of easy clinical use and with such technical features as to allow reduced fields to be imaged, with good spatial resolution. MR imaging could demonstrate with equal accuracy both skeletal-cartilage components and capsulo-ligamentous structures, thus defining associated lesions and small tears. In both degenerative and traumatic lesions of the rotator cuff, MR imaging showed both extent and entity of the pathologic process, with high accuracy in defining the impingement syndrome. MR imaging allowed the depiction of the anterior and posterior glenoid labra, even without intraarticular contrast media. Moreover, MR imaging made it possible to recognize both fractures and degenerative processes within the glenoid labrum on the basis of their signal intensities. This preliminary experience allows the authors to conclude that MR imaging is an accurate and non-invasive diagnostic method for the study of traumatic lesions and of degenerative changes of the shoulder.

[Soft-tissue sarcomas of the extremities. Their assessment with magnetic resonance]

MR imaging was performed on 38 patients with suspected malignant soft-tissue tumors of the extremities. MR diagnostic accuracy was compared with that of other methods. All patients underwent surgical control. In 7 cases MR imaging was employed to demonstrate the tumor response to antiblastic local perfusion. Lesion identification, extension, compartmental evaluation, bone and vascular involvement were the diagnostic parameters considered. In all cases MR imaging detected the lesion, correctly showing the intracompartmental (16 patients) or extracompartmental (22 patients) extension. In 2 out of 6 cases MR imaging did not demonstrate bone invasion, and in 1 case vascular involvement could not be assessed. MR diagnostic accuracy was superior to that of other techniques. Nonetheless, a diagnostic protocol was proposed for the local staging of malignant soft-tissue tumors of the extremities where some diagnostic limitations of MR imaging are taken into account--i.e., inconsistent evaluation of bone and vascular involvement. Plain X-rays and US are the imaging modalities of choice, whereas MR imaging is to be a second-choice diagnostic technique before biopsy. Thus, MR imaging replaces CT, while angiography is to be used in selected cases, where MR imaging is not diagnostic due to vascular involvement.