Short-term outcome of painful bone marrow oedema of the knee following oral treatment with iloprost or tramadol: results of an exploratory phase II study of 41 patients.

OBJECTIVES: To compare the therapeutic effects of oral iloprost and tramadol on the outcome of bone marrow oedema (BME) of the knee by MR imaging and clinical assessment. METHODS: Forty-one patients with painful ischemic or mechanical BME of the knee were enrolled in a double-blind, randomized controlled study. Patients were randomized either to iloprost (n = 21, group 1) or tramadol (n = 20, group 2). The treatment duration was 4 weeks. The Larson knee score was used to assess function before treatment and then 3 days, 1, 2, 3, 4 weeks and 3 months after the start of treatment. Short tau inversion recovery and T1-weighted MR images of the affected knees were obtained before and 3 months after the start of treatment. Bone marrow oedema was assessed visually and by computer-assisted quantification for baseline and follow-up MR examinations. RESULTS: Thirty-three patients completed the study as scheduled. The mean Larson score improved from 58.6 points to 81.8 points in group 1, and from 59.6 points to 86.8 points in group 2, after 3 months (no significant difference between the treatment groups). On MR images, complete BME regression in at least one bone was observed in nine patients (52.9%) in group 1, as opposed to three patients (18.7%) in group 2, after 3 months (P = 0.034). Correspondingly, the median BME volume decreased by 58.0% in group 1, and by 47.5% in group 2. CONCLUSIONS: The analgesic effect of iloprost and tramadol was similar. BME regression on MR images was more pronounced under iloprost treatment.

[Bone marrow edema in the knee. Differential diagnosis and therapeutic possibilities]. / Knochenmarködem im Kniegelenk. Differenzialdiagnostik und therapeutische Möglichkeiten.

The Bone marrow edema (BME) is a common finding when evaluating patients with knee pain by magnetic resonance imaging (MRI). The typical signal patterns of BME are unspecific and can be found with different diseases of the knee. Since different therapeutic approaches are mandatory, differential diagnosis of the several forms of BME is important. In this review, painful BME will be separated into three different etiological groups. Group 1 ischemic BME: osteonecrosis, osteochondritis dissecans, bone marrow edema syndrome and complex regional pain syndrome. Group 2 mechanical BME: bone bruises, microfracture, stress-BME und stress fracture. Group 3 reactive BME: inflammatory gonarthritis, degenerative gonarthrosis, postoperative and tumours. The typical MRI morphologies and differential diagnosis of these BME manifestations will be described. The different therapeutic consequences will also be briefly mentioned.

[Differential diagnosis of bone marrow edema of the knee joint]. / Differenzialdiagnosen des Knochenmarködems am Kniegelenk.

Bone marrow edema of the knee joint is a frequent clinical picture in MR diagnostics. It can be accompanied by symptoms and pain in the joint. Diseases that are associated with bone marrow edema can be classified into different groups. Group 1 includes vascular ischemic bone marrow edema with osteonecrosis (synonyms: SONK or Ahlbäck's disease), osteochondrosis dissecans, and bone marrow edema syndrome. Group 2 comprises traumatic or mechanical bone marrow edema. Group 3 encompasses reactive bone marrow edemas such as those occurring in gonarthrosis, postoperative bone marrow edemas, and reactive edemas in tumors or tumor-like diseases. Evidence for bone marrow edema is effectively provided by MRI, but purely morphological MR information is often unspecific so that anamnestic and clinical details are necessary in most cases for definitive disease classification.

[MRI after meniscus and cruciate ligament surgery]. / MRT nach Meniskus- und Kreuzbandoperationen.

Nowadays, due to its high diagnostic accuracy, MR imaging is the method of choice for the evaluation of knee joint disorders pre- and postoperatively. Accurate diagnosis is sometimes possible only if the reporting radiologist has knowledge of the therapeutic procedures and the surgical report. Frequently, further therapeutic management is strongly influenced by MR examinations and radiological reports.

[Middle field and low field magnetic resonance tomography in wrist injuries]. / Mittelfeld- und Niederfeld-Magnetresonanztomographie bei Handgelenkverletzungen.

PURPOSE: To evaluate the diagnostic value of magnet resonance imaging in comparison of a dedicated 0.2-T unit and a 1.0-T unit in patients with clinically suspected scaphoid fractures and other wrist fractures. MATERIAL AND METHODS: In 20 patients (14 m/6 f) with clinically suspected scaphoid fractures and a normal six view radiographic exam, magnet resonance imaging was performed first with the dedicated 1.0-T unit and afterwards with the 0.2-T unit within 7 days after trauma. T1 weighted spin-echo, STIR and T2-weighted 3D GRE sequences were performed. RESULTS: The 0.2 Tesla dedicated system is inferior to the 1.0 Tesla unit concerning the outcome of the 3 examiners. Especially the areas of bone bruise showed different results: each examiner detected at least two more cases of bone bruise with the 1.0 Telsa unit, which could not be defined with the 0.2 Tesla unit. CONCLUSIONS: This study shows, how utmost sensitive magnet resonance imaging is referring to unremoved fractures of the scaphoid and to other wrist abnormalities. Results with the 0.2 Tesla dedicated system was inferior compared to the 1.0 Tesla unit.

[Diagnostic imaging of giant cell tumors]. / Riesenzelltumoren in der Bildgebung.

Although classified as benign neoplasms, giant cell tumors are locally aggressive with a high recurrence rate of 30-50%. The histological appearance include osteoclast-like, multinucleated giant cells and round to spindle-shaped mono-nuclear stromal cells. These neoplasms predominately affect adults in the third and forth decades of life (70-80%). Giant cell tumors predominately arise in long tubular bones (75-95%) with the majority occurring around the knee (50%). The next most common site being the distal radius (10%). The epicenter of giant cell tumors is in the epiphysis. The radiographic signs of giant cell tumors are a geographical radiolucency with no internal mineralization, a thinning of the cortex, eccentric in the epiphysis of long bones. MRI signs of giant cell tumors are high signal intensity in T2-weighted images, high contrast media enhancement, fluid levels, signs according to haemorrhage and haemosiderin deposition. CT shows the expanded and thinned cortex. Plain radiographs remain the mainstay of diagnosis of giant cell tumors. MRI and CT are important for staging and therefore for surgical planning.

Diagnosis of occult scaphoid fractures and other wrist injuries. Are repeated clinical examinations and plain radiographs still state of the art?

To examine the efficacy of repeated clinical examinations and follow-up radiographs, 121 patients were prospectively and consecutively randomised and clinically followed until a final diagnosis was achieved. All of these patients additionally underwent magnetic resonance imaging (MRI) scans within an average of 3 days after trauma to control the results of this study. MRI detected 112 injuries in 82 patients (67%). Twenty-eight (25%) of these injuries were scaphoid fractures. There were 15 fractures of other carpal bones, 14 avulsion fractures of extrinsic ligaments (AFL), 26 other bone injuries (fractures of distal radius, fractures of radial styloid, ulnar head fracture metacarpal fracture, bone bruises), and 29 soft tissue injuries (triangular fibro-cartilaginous complex injuries, complete or partial ruptures of the scapholunate ligament, ruptures of the radial collateral ligament, hemarthrosis). By means of repeated clinical examinations and plain scaphoid views, experienced observers were able to detect all the occult scaphoid fractures within 38 days, as well as most of the other fractures about the wrist except one fracture of the triquetrum. Soft tissue injuries, however, were diagnosed only in two cases of complete scapholunate ligament tears. It was further obvious that 70% of all scaphoid fractures and 60% of the AFLs were detected in a review of the initial X-rays by experienced surgeons. Only 30% of all scaphoid fractures detected were really occult and all of these were diagnosed correctly. This prospective study demonstrates that clinical and radiological standard procedures are reliable in the diagnosis of occult fractures of the carpus and wrist when performed by experienced observers. MRI scans are indicated for early diagnosis of occult fractures and soft tissue injuries about the wrist.

["Transient osteoporosis" as a special reversible form of femur head necrosis]. / Die "transiente Osteoporose" als reversible Sonderform der Hüftkopfnekrose.

There is still controversy whether transient osteoporosis of the hip joint represents a distinct self-limiting disease, or reflects only an early, reversible subtype of non-traumatic osteonecrosis (ON). Transient osteoporosis has several synonyms: algodystrophy of the hip; transient marrow oedema; or bone marrow oedema syndrome--BMOES. Clinical presentation of BMOES shows mechanical hip joint pain, ON risk factors, and a diffuse bone marrow oedema in MR imaging. Histomorphological changes resemble early ON, but with diffuse sufficient repair in BMOES and focal and insufficient repair only at the border of the necrotic lesion in ON. Therefore the clinical course and outcome are significant different, with restitution occurring in BMOES, while progressive destruction of the joint takes place in ON. So far, the preferred treatment strategies are protected weight bearing for BMOES, but operative treatment for ON. In a prospective study of patients with BMOES, the clinical, radiographic, and MRI course of 43 hip joints after core decompression treatment were investigated. All patients showed immediate relief of pain after surgery and the average duration of symptoms with conservative treatment could be dramatically reduced by core decompression from 6 months down to 2 months. There were no perioperative complications. Based on our experience with over 100 BMOES patients, we are convinced that this syndrome represents not a distinct disease but an early reversible subtype of non-traumatic ON. Due to the excellent clinical results of core decompression, we recommend this operative therapeutical concept in patients with painful BMOES.

Atypical appearance of elastofibroma dorsi on MRI: case reports and review of the literature.

Three patients with histologically proven elastofibroma dorsi underwent MRI, using T1-weighted, T2-weighted, STIR (short inversion time inversion recovery), and contrast-enhanced SE sequences. All lesions typically displayed low signal intensity masses interspersed with areas of high signal intensity on T1- and T2-weighted SE images. Contrary to prior reports, two patients showed marked enhancement of the mass after administration of Gd-DTPA. Although the characteristic signal intensity on conventional T1- and T2-weighted images may lead to the early diagnosis of this rare tumor, radiologists should be aware that marked contrast enhancement may be representative in elastofibroma dorsi.

[Staging of musculoskeletal tumors in diagnostic imaging]. / Staging muskuloskeletaler Tumoren in der Bildgebung.

The staging of primary malignant bone and soft tissue tumors requires adherence to a unified staging system. The staging system of the American Joint Commission for Cancer, the Enneking system, and the Hajdu system are described in respect of the radiologic staging criteria. Plain film radiography can estimate the biological aggressiveness of a bone tumor and in many cases narrow the differential diagnosis. Computed tomography is most sensitive in depicting cortical erosions and calcified periosteal reactions as well as in screening for distant metastasis. Angiography is mainly employed for vascular tumors and for the monitoring of interventional procedures such as tumor embolization. For both bone and soft tissue tumors, magnetic resonance tomography is the method of choice for the staging of intra- and extramedullary tumor extension, for the differentiation of neighboring compartments, and in the detection of invasion of the regional neurovascular bundle. After administration of contrast agents, the mode of enhancement gives further information on the nature of the tumor. With consistent application of the staging criteria in preoperative imaging, limb-saving therapy can be employed more often and the prognosis of the disease can be improved.

Magnetic resonance arthrography (MRA) in the postoperative shoulder.

To evaluate changes in capsular mechanisms and the labroligamentous complex with magnetic resonance arthrography (MRA) after shoulder surgery and to establish possible criteria for the expected post-operative appearance of the shoulder. MRA of the shoulder was performed in 16 patients, before and 6 months after undergoing arthroscopic surgery for recurrent unidirectional dislocation. MR studies were performed after application of a constant amount of contrast solution (2 mmol Gd-DTPA). Axial and coronal oblique T1-weighted images were obtained with and without fat suppression techniques. Anterior (a) and posterior (p) capsular distances were measured, and the p/a ratio was established. Capsule thickness, capsular leaking, estimation of the volume of the axillary recess, appearance of the glenohumeral ligaments, and evidence of labral lesions were compared on pre- and postoperative images. Mean anterior capsular distance (a) decreased from 9.73 +/- 1.03 mm preoperatively to 5.27 +/- 2.49 mm postoperatively, whereas dorsal capsular distance (p) increased from 6.13 +/- 2.36 to 8.93 +/- 2.37. The p/a ratio increased from 0.64 +/- 0.25 to 2.36 +/- 2.54 (p = 0.007). Capsular leaking was suspected preoperatively in seven patients, but was not evident postoperatively. Capsular thickness and the estimated volume in the axillary recess did not change significantly. Contrast extension into pre-existent labral tears (nine patients) decreased or were not evident postoperatively. Changes in the appearance of the glenohumeral ligaments were found in six patients. Changes in capsular distances might be indicative of a decreased capsular laxity and could be a valuable criterion in the evaluation of the postoperative shoulder. Postoperative follow-up of labral tears is demonstrated by a decrease in contrast extension into or under a tear. Reactive capsular thickening or scar tissue formation can be reactive or preexistent. Changes in ligaments might be secondary to surgery. MRA may be helpful in the reevaluation of patients with suspected recurrent instability.

MRI visualization of proteoglycan depletion in articular cartilage via intravenous administration of Gd-DTPA.

The effect of intravenous administration of gadolinium diethylenetriamine-pentaacetic acid (Gd-DTPA) on MR images was studied in vitro, using pathologic osteochondral specimens removed during surgery for total endoprosthesis, and in vivo, on a group of volunteers. In ex vivo specimens, lesions of different shape having lower T1 were detected which corresponded to areas with depleted proteoglycans found histologically. In vivo experiments on young volunteers showed that the time course of cartilage enhancement was different for different anatomies. The time for maximum enhancement ranged from 45 min for the ventral femoral condyle to 270 min for patellar cartilage.

[MRI arthrography of the ankle joint]. / MR-Arthrographie des Sprunggelenkes.

Due to its superior soft tissue contrast conventional MRI is the imaging method of choice in the evaluation of ankle joint disorders. Conventional MR imaging can accurately demonstrate normal or acutely injured ligaments; however, in subacute and chronic injury joint fluid necessary for delineation of injured ligaments is absent and MR arthrography should be performed. MR arthrography uses the intraarticular injection of contrast material to distend the joint, yielding improved discrimination of intraarticular structures. This joint distension with MR arthrography is also helpful in the staging of osteochondritis dissecans, since in cases of unstable lesions tracking of contrast material into the interface can be more easily demonstrated. Finally, high contrast and joint distension by MR arthrography improves the detection of intraarticular loose bodies, which often require surgery. MR arthrography, although invasive, may provide additional information in various ankle joint disorders.

[Chronic diseases of the ankle joint]. / Chronische Krankheitsbilder am Sprunggelenk.

The etiology of chronic diseases of the ankle joint comprises a wide spectrum including chronic inflammatory processes and chronic degenerative, tumorous and neuropathic processes, as well as some specific syndromes based on chronic changes of the ankle joint. Of the inflammatory processes, chronic juvenile arthritis (JVC) is the most common disease. However, also Reiter disease, psoriasis or chronic monoarthritid diseases such as gout, as well as granulomatous diseases (tuberculosis, sarcoidosis) and fungal infections, may affect the ankle joint in a chronic course. Chronic degenerative changes are usually secondary due to abnormal positioning of the joint constituents or repetitive trauma. Neuropathic changes, as frequently seen in the course of diabetes, present with massive osseous destruction and malposition of the articular constituents. Chronic osseous as well as cartilaginous and synovial changes are seen in hemophilic patients. Chronic traumatic changes are represented by pigmented villonodular synovitis (PVNS), and chondromatosis, both with a predilection for the ankle joint. Due to the possibilities of magnetic resonance imaging (MRI), diagnosis of chronic ankle changes includes chronic ligamentous, tendinous and soft tissue changes. With the use of MRI, specific syndromes can be defined which particularly affect the ankle joint in a chronic way, such as the os trigonum syndrome, the anterolateral impingement syndrome and the sinus tarsi syndrome. Nevertheless, plain film radiographs are still the basic element of any investigation. MRI, however, can be potentially used as a second investigation, saving an unnecessary cascade of investigations with ultrasound and CT. The latter investigations are used only with very specific indications, for instance CT for subtle bone structures and sonography for a limited investigation of tendons or evaluation of fluid. Particularly due to the possibilities of MRI and the development of special gradient-echo imaging or high-resolution coils, the investigation of the ankle joint still offers a wide spectrum of innovation for the next years, which is particularly enforced by the increasing demand for specific diagnosis of chronic diseases in orthopedic medicine.

The postoperative shoulder.

Because disability and pain may persist or recur after shoulder surgery, visualization of the postoperative shoulder before further treatment is of great interest. Postoperative status is reevaluated most frequently after rotator cuff repair, capsulorrhaphy in patients with chronic instability, and acromioplasty, where postoperative symptoms are clinically difficult to distinguish from rerupture or inadequate surgical results. Postoperative evaluation or follow-up after surgical treatment of tumors or surgical repair of shoulder injuries are other potential indications. Whereas surgical procedures for osseous components primarily will be evaluated by plain film radiographs, magnetic resonance imaging is a valuable tool for other sites of surgical treatment, such as soft-tissue components, with further potential indication for magnetic resonance arthrography. This article focuses on normal and abnormal postoperative findings in the shoulder, with emphasis of magnetic resonance imaging, and discusses specific findings based on magnetic resonance arthrography.

Magnetic resonance imaging of the postoperative knee.

Due to the recent development of arthroscopic techniques in meniscal surgery and anterior cruciate ligament reconstruction, an increasing number of postoperative patients are referred for a magnetic resonance examination of the knee because of recurrent injury. Contrary to the nonoperative patient, T2-weighted sequences and, in unequivocal cases, magnetic resonance arthrography play the most important role in the evaluation of a possible meniscal retear. In patients with anterior cruciate ligament reconstruction, the changes of the magnetic resonance appearance of the anterior cruciate ligament graft during the first year after surgery must be considered in the diagnosis of retears. Recent developments in articular cartilage defect repair and the possible role of magnetic resonance imaging in the follow-up are discussed.

The postoperative spine.

During the last decade, magnetic resonance imaging (MRI) mostly has replaced computed tomography for evaluation of spinal surgery patients. The inherent advantages of MRI are obvious for this particularly difficult field of imaging. With MRI, it is possible to demonstrate anatomic as well as pathological and iatrogenic changes in three different imaging planes and countless neighboring planes and to obtain a superior view of the complex postoperative situation regardless of the spinal level imaged. Soft-tissue masses in particular can be identified more readily and located within three-dimensional space. One of the major advantages is that the nature and histology of the mass can be estimated precisely using different MR sequences in combination with intravenous contrast media. The most important benefit may be demonstration of inflammatory and hemorrhagic masses in the early postoperative periods (with special emphasis on alterations visible in the spinal cord itself) as well as repair processes and ongoing degeneration in later stages. This visualization is possible even when their extent is limited. In the postoperative spine, the application of MRI was facilitated with the advent of new materials, such as titanium alloys, used for surgical instrumentation. These new materials limit the amount of artifacts visible on MR images. Earlier implants made of other metallic material prohibit the use of computed tomography in the spine. This article provides a brief overview of the progress in spinal surgery and focuses on the developments in MRI techniques during the last decade. Technical questions about imaging of spinal instrumentation are discussed. "Normal" postoperative findings needed for interpretation of pathologic conditions are also discussed. Finally, the most important frequently asked questions from referring surgeons that radiologists must be able to answer by MRI are presented.

Alveolar rhabdomyosarcoma in a 68-year-old patient identified by cytogenetic analysis of bone marrow.

Pancytopenia and fulminant disseminated intravascular coagulation in a 68-year-old woman suggested an acute hematologic malignancy. However, cytogenetic analysis on a bone marrow sample revealed a near-tetraploid karyotype with an isochromosome 1q and a translocation (2;13) (q35;q14), which was suggestive of an alveolar rhabdomyosarcoma (ARMS). This diagnosis was subsequently confirmed by indirect immunohistochemistry. ARMS has not yet been observed in a patient of this age. Thus, our case underlines the importance of cytogenetics, to establish an a priori unexpected tumor diagnosis.

[Diagnostic reliability of 0.2 Tesla dedicated MRI low-field strength equipment in traumatology]. / Die diagnostische Sicherheit von 0.2 Tesla dedizierten MRT Niederfeldgeräten in der Traumatologie.

Anatomical dedicated low-field-strength MR imaging (non-whole-body-systems) has been developed for examinations of the peripheral joints. It has several advantages compared to high-field-strength MR imaging (whole-body-systems). The dimensions are small, the noise is not as bad as in whole body systems and people do not suffer of claustrophobic attacks. However, our results of a prospective blinded study in 56 patients with three different kinds of peripheral joint injuries demonstrated that the 0.2 T dedicated system showed a significant lower rate of diagnostic accuracy compared to middle and high-field-strength MR imaging and scored with obvious lower image quality ratings.