Injuries of the lateral collateral ligaments of the ankle: assessment with MR imaging.

The aim of this study was to evaluate the ability of MRI to display injuries of the lateral collateral ligamentous complex in patients with an acute ankle distorsion trauma. The MR examinations of 36 patients with ankle pain after ankle distorsion were evaluated retrospectively without knowledge of clinical history, outcome and/or operative findings. The examinations were performed on a 1. 5-T whole-body imager using a flexible surface coil. The signs for ligamentous abnormality were as follows: complete or partial discontinuity, increased signal within, and irregularity and waviness of the ligament. The results were compared with operative findings in 18 patients with subsequent surgical repair. Eighteen patients with conservative therapy had a follow-up MR examination after 3 months. There was 1 sprain, 3 partial and 32 complete tears of the anterior talofibular ligament, and 5 sprains, 5 partial, and 7 complete tears of the calcaneofibular ligament. There were no lesions of the posterior talofibular ligament. Compared with surgery, MRI demonstrated in 18 of 18 cases the exact extent of anterior talofibular ligament injuries and underestimated the extent in 2 of 8 cases of calcaneofibular ligament injury. In patients with follow-up MRI after conservative therapy, a thickened band-like structure was found along the course of the injured ligament in 17 of 18 cases. The absence of ligament repair after conservative treatment was confirmed during operative revision in one case. The MRI technique allows for grading of the extent of injury of the lateral collateral ligamentous complex after acute ankle strain. It seems to be suitable for monitoring the healing process after conservative-functional treatment of ligament tears.

Effect of anatomic distribution of pulmonary emboli on interobserver agreement in the interpretation of pulmonary angiography.

OBJECTIVE: This study examines the anatomic distribution of emboli on pulmonary angiography and attempts to determine the relationship of vessel size to interobserver agreement, two factors having important implications in comparing pulmonary angiography with cross-sectional imaging for pulmonary embolism. MATERIALS AND METHODS: One hundred twenty-five consecutive pulmonary angiograms were reviewed retrospectively by three interventional radiologists. Initial interpretations were recorded and compared to determine interobserver agreement on a per-patient and per-embolus basis. Discordant interpretations were reviewed by all radiologists for a consensus interpretation. RESULTS: Unanimous per-patient agreement occurred in 91% (114/125) of initial interpretations. The largest artery containing acute pulmonary embolism was segmental or larger in 24 patients (83% of patients with acute positive findings, 19% of all patients) and subsegmental in only five patients (17% and 4%, respectively). On a per-patient basis, initial interobserver agreement averaged 45% and unanimous consensus agreement was achieved for 79% of patients having isolated subsegmental pulmonary embolism. Consensus readings altered initial per-patient interpretations for 30% of patients having only subsegmental pulmonary embolism; per-embolus interpretations were altered for 37% of all subsegmental emboli. CONCLUSION: Subsegmental emboli occurring as isolated findings are relatively rare. Approximately one third of subsegmental emboli and one third of patients having isolated subsegmental emboli may be initially misdiagnosed on pulmonary angiography. Objections to cross-sectional imaging for pulmonary embolism based on the inability to detect subsegmental pulmonary embolism when compared with pulmonary angiography should be reexamined with this data in mind.

Single institution prospective evaluation of the over-the-wire Greenfield vena caval filter.

PURPOSE: To assess the technical and clinical success of the over-the-wire (OTW) Greenfield inferior vena caval (IVC) filter. MATERIALS AND METHODS: Prospective evaluation of the OTW Greenfield filter in 47 patients was performed during the course of 18 months. Technical success and deployment problems were documented. Caval perforation, leg asymmetry, and tilt were evaluated with a postprocedure, noncontrast computed tomographic (CT) scan. Follow-up was performed at 6- and 12-month intervals after the procedure and included a clinical history, chart review, and magnetic resonance (MR) imaging examination of the IVC. RESULTS: Ninety-one percent of filters were placed without technical difficulties and 100% were successfully deployed. Technical difficulties included sheath kinking prior to deployment (n = 3), initial incomplete filter opening (n = 1), and wire entrapment within the filter (n = 1). Of 38 patients evaluated with CT, there was no case of caval perforation. Twenty-one patients (55%) demonstrated tilt and 14 (37%) had leg asymmetry. Tilting occurred more frequently when the filter was placed from a femoral approach (51%) than from a jugular approach (12%). Of patients with leg asymmetry, the vena cava was narrow in anteroposterior (AP) dimension in five (36%). Of 13 deaths, none were attributed to pulmonary embolism. One patient (2%) had a recurrent pulmonary embolus. Two of 16 patients (12%) with MR imaging follow-up had documented IVC thrombosis. CONCLUSIONS: The OTW Greenfield filter has an effective delivery system, with few difficulties encountered during deployment. Filter tilt and leg asymmetry are common. The etiology of leg asymmetry is likely multifactorial but is often associated with a cava with a small AP diameter. Because OTW deployment appears to offer no benefit in centering the filter, the authors have elected to remove the wire prior to filter deployment to avoid possible entanglement. MR imaging follow-up reveals an acceptable incidence of IVC thrombosis.

[MRI of knee ligaments: error analysis with reference to meniscus and anterior cruciate ligaments in an arthroscopic controlled patient cohort]. / MRT des Kniegelenkes: Fehler-analyse bezüglich der Meniskus- und Kreuzbanddiagnostik an einem arthroskopisch kontrollierten Patientenkollektiv.

PURPOSE: To categorise discrepancies in findings of the menisci and anterior cruciate ligament (ACL) between arthroscopy and MRI. MATERIALS AND METHODS: The MRIs of 236 patients were retrospectively analysed by an experienced radiologist without knowledge of clinical and/or operative findings. Discrepancies in arthroscopic findings were reevaluated together with the arthroscopist to determine their cause of error. RESULTS: The diagnostic accuracies for injuries of the medial and lateral meniscus and the ACL were 92.4%, 92.4%, and 94.1%, respectively. For the menisci, causes for discrepancies in findings (n = 31) were: overinterpretation of central signal intensities with contact to the meniscal surface but without disturbance of the meniscal contour as a tear (n = 12), insufficient arthroscopie evaluation of the knee joint (n = 11), overlooked tears on MR imaging (n = 6), misinterpretation of normal anatomic structures (n = 1), "magic angle" phenomenon (n = 1), and missed tears at MRI (n = 1). Causes for discrepancies for the ACL (n = 18) were: nearly complete versus complete rupture either at MRI or arthroscopy and vice versa (n = 9), insufficient arthroscopic evaluation (n = 6), insufficient MRI technique (n = 2), and overlooked tear on MR imaging (n = 1). CONCLUSIONS: Discrepant findings between MRI and arthroscopy may be also due to an insufficient arthroscopic evaluation in clinical routine. The close cooperation between surgeons and radiologists improves the understanding of the methods of each other.

[Diagnosis of primary sclerosing cholangitis: prospective comparison of MR cholangiography with endoscopic retrograde cholangiography]. / Diagnostik der primär sklerosierenden Cholangitis: prospektiver Vergleich von MR-Cholangiographie mit endoskopisch retrograder Cholangiographie.

PURPOSE: To assess the accuracy of MR cholangiography (MRC) in the diagnosis of primary sclerosing cholangitis (PSC) in comparison to endoscopic retrograde cholangiography (ERC). METHOD: 20 patients with PSC were examined by ERC and MRC (1.0 T, HASTE sequence). Visualization and pathologic changes of the extra- and intrahepatic bile ducts were evaluated with both methods. RESULTS: Mural irregularities of the common bile duct were seen with MRC in 6/7 cases, stenoses and dilatation of the common bile duct were detected correctly in all patients. Diffuse, multifocal strictures of the intrahepatic bile ducts were the most common intrahepatic findings and correctly diagnosed in almost all patients. Mural irregularities of the intrahepatic ducts in early stages may be missed by MRC because of the limited spatial resolution. MRC is superior to ERC in visualization of nonopacified intrahepatic ducts. CONCLUSIONS: MRC is a reliable, non-invasive method to detect typical diagnostic features of PSC. It should be considered as an adjunct to ERC in patients with suspected PSC for primary diagnosis and as an alternate method for follow-up studies.

[Rupture of lateral ligaments of the ankle joint: MR imaging before and after functional therapy]. / Aussenbandrupturen des Sprunggelenkes--Darstellung mit der MRT vor und nach funktioneller Therapie.

PURPOSE: Documentation via MRI of the healing of ruptured lateral collateral ankle ligaments after functional therapy. PATIENTS AND METHODS: 35 patients with ankle sprain were examined by MRI and stress radiographs, 13 were operated afterwards, 22 patients underwent a functional conservative therapy and were examined by MRI and stress radiographs and second time after three months. RESULTS: MRI reports were correct in 12 of 13 operated cases. After conservative therapy we did not find any disrupted ankle ligament. MRI showed intact ligaments thickened by scar. CONCLUSION: MRI is able to show injuries of the lateral collateral ankle ligaments and demonstrates the healing by scar after conservative therapy.

[Optimizing pelvic MR diagnosis with a new gastrointestinal contrast medium]. / Optimierung pelviner MR-Diagnostik durch eine neues gastrointestinales Kontrastmittel.

AIM: Optimization of pelvic MRI by a new concept of water-equivalent bowel contrast agent. METHODS: We performed contrast enhancement of the bowel by oral application of 1000 ml of an aqueous mannitol solution one hour before pelvic MRI. In addition we performed an enema by 250 ml of water in one patient. RESULTS: Oral and rectal contrast enhancement of the bowel was tolerated without complications by our patients. Pelvic MRI was improved by a better delineation of the bowel. CONCLUSION: The concept of water-equivalent bowel enhancement is promising. It must be assessed by further studies; in particular, it must be compared with the available concepts of positive and negative bowel contrast enhancement.

[The value of MR tomography in traumatic patella dislocations]. / Stellenwert der MR-Tomographie bei traumatischen Patellaluxationen.

PURPOSE: To describe the MR imaging findings in patients with lateral patellar dislocation. MATERIAL AND METHODS: The MRIs of 31 patients with patellar dislocation were evaluated retrospectively. Arthroscopic surgery was performed in 23 cases. RESULTS: Hemarthrosis was found in 30/31, contusions of the lateral femoral condyle in 30/31 and of the medial patellar facet in 26/31 cases. Injury of the medial patellar retinaculum was seen in 28/31 cases. Osteochondral fractures were found in 18 patients; compared to arthroscopy there were one false-positive and 5 false-negative findings concerning loose cartilage bodies. In 7 cases, patellar dislocation was not suspected before MR imaging. CONCLUSION: Hemarthrosis, lateral femoral and medial patellar contusion, and retinacular disruption are typical findings after lateral patellar dislocation. A careful search for free osteochondral fragments is mandatory as it influences the indication and performance of arthroscopic surgery.

[A mannitol solution as an oral contrast medium in pelvic MRT]. / Eine Mannitollösung als orales Kontrastmittel in der pelvinen MRT.

PURPOSE: Improvement of pelvic MRI using peroral administration of an aqueous mannitol solution. METHODS: We retrospectively evaluated magnetic resonance examinations of 72 patients with suspected or proven pelvic abnormalities: In 36 patients, no bowel marking was carried out. In further 36 patients, we performed a contrast enhancement of the bowel by oral application of 1000 ml of an aqueous mannitol solution. RESULTS: 8/36 (22%) patients suffered from diarrhoea, nausea or meteorism as a result of mannitol application. In group 2, an excellent bowel marking of the small intestine could be obtained in 36/36 (100%) patients. Contrast enhancement of the bowel significantly improved delineation between intestinal structures and pelvic organs or pathologic lesions, respectively. In summary, bowel marking was desirable in 25/36 (69%) of group 1 and helpful in 26/36 (72%) of group 2. CONCLUSION: Aqueous mannitol solution is a safe bowel contrast agent and improves the diagnostic value of pelvic MRI, but in some cases delineation between marked bowel and cystic pelvic lesions may be uncertain.

[The magnetic resonance tomographic findings following the resection arthroplasty of the caput humeri]. / Magnetresonanztomographische Befunde nach Resektionsarthroplastik des Humeruskopfes.

PURPOSE: The resection of the humeral head is normally carried out only with respect to four-part and dislocation fractures in elderly patients. The purpose of this study was to examine whether there is a correlation between the clinical results and the MRI findings. MATERIAL AND METHODS: 8 patients underwent clinical and MR examination two to 6 years after resection. RESULTS: A cartilage-like tissue formation between the remaining humeral head and the glenoid fossa, with signal intensities comparable to hyalin cartilage was found in all patients. CONCLUSION: The good functional results following resectional surgery of the humeral head can partially be related to new substitute cartilage resulting from a chondroid metaplasia.

Parosteal osteosarcoma of the talus.

A case of parosteal osteosarcoma in the very rare location of the talus is presented. The radiological, pathological, and clinical characteristics of parosteal osteosarcoma are described and the differential diagnosis discussed.

[THe differentiation between benign and malignant liver lesions by unenhanced MRI]. / Differenzierung zwischen benignen und malignen Leberläsionen mit der Nativ-MRT.

UNLABELLED: The aim of the study was to establish qualitative criteria for differentiating between malignant and benign focal lesions of the liver using unenhanced MRT at 0.5 Tesla. PATIENTS AND METHOD: 72 patients with 103 focal liver lesions were examined with T1 and T2 weighted SE sequences. The images were examined by three radiologists according to qualitative criteria (homogeneity, form and signal of the lesions compared with liver, spleen and muscle). RESULTS: The most specific sign applying to 90% of malignant lesions were diffuse or irregular contours on T2 weighted sequences; this had a sensitivity of 43%. For all other features, specificity for malignancy was less than 67%. CONCLUSION: Using these sequences and criteria it is not possible to distinguish between malignant and benign lesions of the liver with sufficient accuracy.

[MRI monitoring of reconstruction of ligaments of the upper ankle joint after injury]. / MRT-Monitoring der Wiederherstellung des Bandapparats des oberen Sprunggelenks nach Verletzung.

The therapy of fibular ligament ruptures is still a controversial subject. Reports on healing processes following operative or conservative treatment have been verified hitherto by means of clinical examinations and stress tests. The MRT, as a highly sensitive non-invasive method, allows exact documentation of the ligament structures in the ankle joints. This technique was used in a randomized clinical trial over a 6-month period. The 29 patients (ages 17-51 years) had recent ligament rupture [admission criteria: clinical signs of trauma, talar tilt in anteroposterior stress radiographs (15 kp) > or = 10 degrees, talar shift > or = 10 mm] were examined with regard to ligament healing during functional therapy with AIRCAST pneumatic leg braces. Within the first week an MRT was done for verification of ligament injury. Treatment was conservative and functional: lower leg cast for 2 weeks and subsequent mobilization with protection provided by an AIRCAST brace. Follow-up examination was 3 months after injury, taking the form of clinical examination, a-p-radiographs with stress tests, and MRT. In all patients both clinical and radiological examination confirmed that ligament structures had healed, as was also verified by MRT.

[1H-MR spectroscopic imaging: an approach to evaluating alcohol breakdown in the brain]. / 1H-MR-spektroskopische Bildgebung: ein Ansatz zur Evaluierung des Alkoholabbaus im Gehirn.

The local alcohol concentration in the human brain was determined in 10 cases using MR spectroscopic imaging. Therefore 7 subjects with an average blood alcohol concentration of 0.8/000 were examined after oral intake of alcoholic beverages. Varying alcohol concentration was found intracranially which was recorded spectroscopically w.r.t. time. Relatively high ethanol concentrations were determined in the cerebellum as well as in the ventricular system. Contrary to this, lower concentrations were found in the regions of grey and white matter.

[Reliability of imaging procedures in multi-visceral gynecologic operations of the pelvis]. / Zuverlässigkeit bildgebender Untersuchungsverfahren bei multiviszeralen gynäkologischen Operationen im kleinen Becken.

Between March 1989 and December 1992, a total of 85 pelvic exenterations were performed in the Department of Gynaecology and Obstetrics of the University of Mainz. To assess the accuracy of preoperative Magnetic Resonance Imaging (MRI) and Computer Tomography (CT) with regard to tumour localisation and spread, the results of 28 MRI and 14 CT examinations were compared with the postoperative histological findings. For this widely varying patient group that had undergone a broad range of previous treatments, MRI produced an accurate forecast in 56% of cases (CT, 36%). In 33% of the patients tested, the diagnosis based on MRI was partially correct (CT, 43%), whereas the MRI results fundamentally disagreed with the actual findings in 11% of cases (CT, 21%). We conclude that both MRI and CT are of great value in the planning of operations and for informing patients about their condition; however, in individual cases, an intraoperative quick-section diagnosis is necessary to provide details of tumour spread. If the extent of tumour spread is uncertain, the results of CT and/or MRI should not deter the surgeon from the radicality of the planned operative intervention.

[Gadolinium-DTPA (Magnevist) as contrast medium for arterial DSA]. / Gadolinium-DTPA (Magnevist) als Kontrastmittel für die arterielle DSA.

16 DSA investigations using intra-arterial Gd-DTPA were performed on 12 patients. The contrast medium was administered either as a 0.5 molar gadolinium solution (commercially available) or diluted with distilled water to a 0.2-0.4 molar gadolinium solution. The injection was made either by pressure injector or by hand. The aortic arch, abdominal aorta and pelvic and lower limb arteries were examined. 14 of the 16 procedures were diagnostically adequate, but compared with iodinated contrast materials, contrast was less marked. There were no cardiovascular, neurological or allergic side effects. Three patients suffered a feeling of heat and one patient had mild pain during the injection. Even large volumes rapidly injected (up to 20 ml/s of the commercially available solution) were well tolerated. DSA with intra-arterial Gd-DTPA seems to be a suitable alternative for vascular imaging if iodine-containing contrast materials are contraindicated.

[Application possibilities of MR arthrography in diseases of the shoulder joint]. / Einsatzmöglichkeiten der MR-Arthrographie bei Erkrankungen des Schultergelenkes.

In a prospective study possible indications for MR arthrography of the shoulder were evaluated. 37 patients were examined before and after intraarticular administration of a 2-mmolar solution of Gd-DTPA. MR arthrography was performed if there was no joint effusion and/or an uncertain finding concerning the rotator cuff or the capsulolabral complex on plain MR images. MR arthrography leads to a better demonstration of labrum pathology in 11/22 patients and to a superior delineation of the capsuloligamentous apparatus in 20/22 cases. In 9/15 patients with impingement lesions MR arthrography allowed a differentiation of severe tendinitis from partial and small full-thickness tears of the rotator cuff. MR arthrography of the shoulder joint enhances the accuracy of MR in case of an uncertain finding on plain MR images.

[MRT for surgical planning in anal atresia]. / MRT zur Operationsplanung bei Analatresien.

We evaluated in this study the value of preoperative examinations of anal atresia with an optimised MRI strategy. 13 patients with anorectal anomalies, most of them younger than one year, underwent an MRI examination of the pelvis. 10 of these patients were operated afterwards. Compared with the situs shown by the operation the results of the MRI examination were very exact in all cases in respect of the level of atresia and the development of the striated muscle complex. Fistulas could be completely described in most cases. MRI demonstrated additional lesions in some patients which were of great importance for planning the further treatment of the patients. As a consequence MRI can give valid information on anal atresia for planning the operative treatment.