Anatomy of the normal knee as seen by magnetic resonance imaging

Nuclear magnetic resonance imaging (MRI) was used to study the normal knee. As well as revealing bone quality, MRI provided useful information on intra-articular and extra-articular soft tissues. Midsagittal views gave clear images of the cruciate ligaments, and of the patellar and quadriceps tendons. Parasagittal views were the best for delineating the menisci which, like ligaments and tendons, are of low intensity; the semimembranosus tendon and its insertion to the proximal tibia were also seen clearly in these views. The cruciate ligaments and menisci, though visible in the coronal view also, were better seen in the sagittal view. Axial views provided information on the structure of the patella, its cartilage, the patellofemoral joint and posterior soft-tissue structures.     

Preoperative marking of musculoskeletal tumors guided by magnetic resonance imaging

BACKGROUND: The purpose of this study was to evaluate a new stereotactic method for preoperative coil-marking of musculoskeletal tumors with use of interventional magnetic resonance imaging. METHODS: Nine patients with a soft-tissue or bone-marrow tumor were referred to our department for preoperative marking of the extent of the lesion. In one patient, two lesions were marked. Guidance for the punctures and the delivery of the coils was provided by an open low-field magnetic resonance imaging system with horizontal access. After imaging of the extent of the lesion, magnetic resonance imaging-compatible titanium coils were placed with use of nearly real-time or step-by-step magnetic resonance imaging control. The coils were placed up to seventy-two hours before the surgery. The inclusion of the tumor borders within the area of the excision was examined with cross-sectional histological analysis of surgical specimens. RESULTS: The tumor-marking intervention was successfully performed with the guidance of magnetic resonance imaging only in all patients. Preoperatively, nineteen coils were used to mark the ten lesions in the nine patients. All of the coils were easily located with intraoperative fluoroscopy. No coil migrated between the time of the percutaneous marking and the surgery. Histological examination of the resection borders revealed no residual tumor cells. No complications were observed, and, after a mean of twenty-three months of follow-up, no tumor had recurred. CONCLUSIONS: Preoperative coil-marking guided by magnetic resonance imaging for exact delineation of a musculoskeletal tumor is technically feasible and can readily demonstrate the full extent of the tumor. Use of magnetic resonance fluoroscopy reduces the time needed for the intervention. We recommend the coil-marking technique.     

Labral lesions: An elusive source of hip pain case reports and literature review

Three cases are presented highlighting varied aspects of labral lesions as a primary or contributing source of mechanical hip pain; including one chronic labral tear associated with old trauma, an acutely entrapped labrum, and a degenerative labral tear associated with osteoarthritis. The diagnosis of labral lesions may be elusive. Arthrography, double-contrast arthrography followed by computerized tomography, and magnetic resonance imaging all have been reported in the assessment of these lesions with variable success. Often, the clinical presentation, including history and physical examination, will yield useful information. A fluoroscopically guided intra-articular injection of the hip is a very useful diagnostic tool for differentiating an intra-articular source of hip symptoms, such as labral lesions, from an extra-articular source. Labral tearing can readily be assessed by arthroscopy and many can be successfully addressed by operative arthroscopy. However, there are many variations in the arthroscopic anatomy of the acetabular labrum.     

The diagnostic value of needle biopsy for musculoskeletal lesions

The purpose of this study was to assess the diagnostic value of imaging-guided core needle biopsy for the diagnosis of musculoskeletal lesions. Between 2004 and 2007, 309 biopsies (ultrasound 151, computed tomography 89, and fluoroscopy 69) were included. There were 142 soft tissue and 167 bony lesions. Diagnostic yields and accuracies were assessed using the chi-square test or Fisher’s exact test with Bonferroni’s correction when necessary. Overall diagnostic yield was 90.6% for all 309 lesions (bone 91.6% vs. soft tissue 89.3%, p = 0.5125). The diagnostic accuracy of the 185 core needle biopsies, which were confirmed by definitive surgical biopsies, was 84.3% (bone 88.9% vs. soft tissue 79.1%, p = 0.0669). The yields of homogenous bone tumours (96.8%) were not significantly higher than those of bone tumours with a heterogenic architecture (86.4%, p = 0.0794). The difference between accuracies for homogenous bone tumours (89.1%) and heterogenous bone tumours (85.0%) was not significant (p = 0.6930). However, for soft tissue tumours, homogenous tumours had a significantly higher diagnostic yield than heterogenous tumours (97.5% vs. 81.4%, p = 0.0036). Diagnostic accuracy for homogenous tumours was also significantly higher than that for heterogenous soft tissue tumours (94.4% vs. 60.6%, p < 0.0001). The image-guided percutaneous needle biopsy of musculoskeletal lesions is a safe and effective procedure if it is performed selectively in soft tissue tumours with homogenous architectures.     

Soft-tissue sarcoma in adults: Imaging appearances,pitfalls and diagnostic algorithms

This article provides an overview of the current knowledge regarding diagnostic imaging of patients with soft-tissue sarcomas, which is a heterogeneous group of rare mesenchymal malignancies. After an initial contextualization, diagnostic flow-chart based on initial radiological findings of soft-tissue masses (with specific focus on adipocytic soft-tissue tumors [STTs], hemorragic STTs and retroperitoneal STTs) are provided considering relevant results from novel researches, guidelines, and experts’ viewpoints, with the aim to help radiologists and clinicians in their practice. Particularly, the central place of sarcoma reference centers in the diagnostic and therapeutic management is highlighted, as well as the pivotal role that radiologists should play to correctly identify patients with soft-tissue sarcoma at the initial stage of the disease. Indications and methods for performing imaging-guided biopsies are also discussed, as well as clues to improve soft-tissue sarcoma grading with conventional and quantitative imaging.     

Magnetic resonance arthrography versus arthroscopy in the evaluation of articular hip pathology

In this study, we compared magnetic resonance arthrography results with hip arthroscopy findings to assess the diagnostic value of this imaging technique in evaluating acetabular labral tears and concurrent articular hip pathology. One hundred one consecutive patients (102 hips) with a clinical diagnosis of acetabular labral tear were assessed using magnetic resonance arthrography and had hip arthroscopy after failing to improve with nonoperative treatment. Magnetic resonance arthrography detected 71 of 93 (76%) acetabular labral tears (92 patients) with five false positive studies in five patients (4.9%). Articular cartilage findings diagnosed by magnetic resonance arthrography were confirmed by arthroscopy in 64 hips in 64 patients (62.7%). With respect to labral pathology, magnetic resonance arthrography showed a sensitivity of 71%, specificity of 44% positive predictive value of 93%, negative predictive value of 13%, and accuracy of 69%. With respect to articular cartilage pathology, magnetic resonance arthrography had a sensitivity of 47%, specificity of 89%, positive predictive value of 84%, negative predictive value of 59%, and accuracy of 67%. Although magnetic resonance arthrography is an excellent positive predictor in diagnosing acetabular labral tears and articular cartilage abnormalities, it has limited sensitivity. A negative imaging study does not exclude important intra-articular pathology that can be identified and treated arthroscopically.     

Evaluation of magnetic resonance imaging in the diagnosis of osteonecrosis of the femoral head. Accuracy compared with radiographs, core biopsy, and intraosseous pressure measurements

The accuracy of magnetic resonance imaging in the detection of osteonecrosis of the femoral head was compared with that of other diagnostic methods in current use: plain radiography, bone-marrow pressure determinations, intramedullary venography, and histological examination of core-biopsy bone specimens. In the first phase of the study, forty-eight patients (ninety-six hips) who were at high risk for avascular necrosis were studied. Abnormal patterns on magnetic resonance imaging, consistent with those seen in necrosis, were found in all hips that were suspected of having Ficat Stage-2 or 3 changes on the basis of radiographic evidence of the disease. Abnormal patterns on magnetic resonance imaging that were characteristic of avascular necrosis were also observed in 17 per cent of the hips that were suspected of having Ficat Stage-0 changes and in 64 per cent of those that showed Stage-1 changes, all with no radiographic changes. In the second phase of the study, twenty-three of the ninety-six hips that were suspected of having early-stage necrosis of the femoral head but showed slight or no radiographic changes were studied by repeat radiographs, Ficat functional evaluations of bone, core biopsies of the femoral head, and magnetic resonance imaging. Of the twenty-three hips, eighteen (78 per cent) had positive changes on magnetic resonance imaging; nineteen (83 per cent) had positive histological evidence of necrosis; and fourteen (61 per cent) had positive findings by bone-marrow pressure studies and intramedullary venography. Although false-negative and false-positive results were observed with magnetic resonance imaging, the over-all results of this study suggest that magnetic resonance imaging may be useful for the early diagnosis of avascular necrosis.     

Wrist arthroscopy in distal radial fractures using a modified horizontal technique

Wrist arthroscopy has today become an important adjunct in the management of displaced intra-articular distal radial fractures, with reduction of joint incongruencies as well as detection and treatment of associated soft-tissue injuries. However, standard upright arthroscopy makes it difficult to combine arthroscopic-assisted reduction with additional treatment of the often comminuted, extra-articular fracture component. This article describes a modified arthroscopic technique in which the arm is blocked in pronation with the traction horizontally over a handle on a normal hand table, without any other changes in the arthroscopy itself. The author has operated on 17 patients using this horizontal technique in combination with arthroscopic-assisted reductions, closed and open osteosynthesis, and soft-tissue procedures. The horizontal technique allows complete treatment of comminuted, unstable distal radial fractures, intra-articular and extra-articular reduction, and bone grafting, as well as assessment and treatment of associated soft-tissue injuries.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 1 (January), 2001: pp E5–E5     

Double-blind assessment of the value of magnetic resonance imaging in the diagnosis of anterior cruciate and meniscal lesions

A prospective double-blind study was undertaken to evaluate the usefulness of magnetic resonance imaging in the accurate interpretation of pathological intra-articular changes in the knee. Forty-seven patients who were scheduled to have arthroscopy and three patients who wer to have arthrotomy volunteered for magnetic resonance imaging preoperatively. The radiologists had no clinical or roentgenographic information about the patients before the evaluation of the magnetic resonance images, and the radiologists' interpretations were unknown to the surgeon before the arthroscopy or arthrotomy was done. Our important observations were limited to the findings in the menisci and in the anterior cruciate ligament. Magnetic resonance imaging had a positive predictive value of 75 per cent, a negative predictive value of 90 per cent, a sensitivity of 83 per cent, and a specificity of 84 per cent for pathological findings in the menisci. For complete tears of the anterior cruciate ligament, the positive predictive value was 74 per cent; the negative predictive value, 70 per cent; the sensitivity, 61 per cent; and the specificity, 82 per cent. We believe that magnetic resonance imaging, when combined with clinical and roentgenographic examination, provides the most accurate non-invasive source of information that is currently available for pathological findings in the menisci and in the anterior cruciate ligament.     

Musculoskeletal ultrasound: applications in the hip

This article illustrates how ultrasound (US) can be useful in the evaluation of painful hips. For an experienced examiner using high quality equipment, US is the imaging test of choice for tendon abnormalities, hernias, bursitis, and dynamic abnormalities such as extra-articular snapping hip. Ultrasound is also useful in screening for hip effusions and guiding diagnostic and therapeutic interventions. Ultrasound has a complementary role to magnetic resonance imaging (MRI) for labral pathology, although MRI or MR arthrography is preferable for most intra-articular pathologies. It is better tolerated, less expensive, and more readily available than MRI, and as US technology continues to improve, its role in hip imaging should grow.     

Correlative anatomy for the mediastinum

Diseases of the mediastinum comprise a wide spectrum of benign and malignant entities that share the same anatomic site within the chest. Correct management often requires a multidisciplinary approach. Diagnostic imaging modalities such as computed tomography (CT), magnetic resonance imaging (MRI), ultrasonography, and positron emission tomography play a major role in the diagnosis of mediastinal diseases and in guiding minimally invasive diagnostic procedures, minimizing the risk of imaging-guided biopsies. This article describes the mediastinal anatomy, correlating the findings of plain radiography, CT, and MRI.     

Popliteal Cysts: Historical Background and Current Knowledge

Popliteal cysts were first described in 1840 by Adams, but it is from Baker's writing in 1877 that we derive the commonly used eponymic term "Baker's cyst." Associated intra-articular lesions are very common with popliteal cysts. Ultra-sonography, arthrography, and magnetic resonance imaging have all proved useful in distinguishing popliteal cysts from other cysts and from soft-tissue tumors about the knee, as well as in identifying coexisting intra-articular lesions. Cysts in pediatric patients are generally self-limited and should be treated conservatively. In the adult population, treatment is primarily nonsurgical. Arthroscopic evaluation is indicated if an intra-articular lesion is causing mechanical symptoms or if there is no response to appropriate conservative treatment, such as use of nonsteroidal anti-inflammatory drugs and compression sleeves. Surgical excision is reserved for cases in which this approach has been unsuccessful.     

The role of colour Doppler ultrasonography in detecting prostate cancer

OBJECTIVE: To determine the usefulness of colour Doppler ultrasonography (CDUS) in detecting prostate cancer, by comparing CDUS with grey-scale transrectal ultrasonography (TRUS) and magnetic resonance imaging (MRI). PATIENTS AND METHODS: In all, 278 patients who underwent prostate biopsies because of an abnormal digital rectal examination, elevated prostate specific antigen levels, and/or abnormal TRUS between May 1998 and November 1999 were evaluated. The diagnostic accuracies of TRUS, CDUS, MRI and combinations of these imaging techniques in detecting prostate cancer were compared, based on the biopsy results. RESULTS: Carcinoma was detected in 233 of 1696 specimens, and 87 patients were diagnosed with prostate cancer. For each detected cancer site, the sensitivity of CDUS was lower than those of other imaging techniques, but CDUS had high a specificity and positive predictive value. The combination of grey-scale TRUS and CDUS or MRI improved the sensitivity and negative predictive value. The specificity and positive predictive value of the combination of grey-scale TRUS and MRI were less than those for grey-scale TRUS alone, while those for the combination of grey-scale TRUS and CDUS were higher than those for grey-scale TRUS alone. Five tumours were isoechoic but seen as hypervascular lesions with CDUS. CONCLUSION: CDUS provides information useful for detecting prostate cancer when used in combination with grey-scale TRUS, and should be included in the routine examination for prostate cancer.     

Magnetic resonance imaging in marrow diseases

Magnetic resonance imaging is an exciting and promising diagnostic tool. It employs a powerful magnet and radio frequency waves to produce details of the human body with no known risk to patients or staff. It produces superior soft-tissue contrast between muscle, fat, ligaments and tendons, nerves, and blood vessels. Magnetic resonance imaging has potential diagnostic value in avascular necroses of bone caused by trauma, Legg-Perthes diseases, sickle cell syndrome, and other conditions. It is useful in determining the extent of marrow lesions, including tumors and metabolic disturbances, muscle trauma and diseases, spinal cord and peripheral nerve lesions including compression neuropathies, and perhaps in preoperative evaluation of the patient with intervertebral disc disease.     

Can Breast Magnetic Resonance Imaging Prevent Biopsy or Change the Management of BI-RADS® Category 4 Breast Lesions?

The BI-RADS® category 4 includes suspicious breast lesions which requires biopsy. The aim of this study is to investigate the contribution of breast magnetic resonance imaging to the management of BI-RADS® category 4 breast lesions detected by mammography and∕or ultrasonography. Thirty-four lesions classified as BI-RADS® category 4A, 4B, or 4C by conventional methods were evaluated with magnetic resonance imaging. All lesions were coded by using the American College of Radiology BI-RADS® lexicon. Each lesion was verified with the result of pathology. Lesions were evaluated as BI-RADS® category 1 in 1 patient (2.9%), category 3 (20.6%) in 7 patients, category 4 in 25 patients (73.6%), and category 5 in 1 patient (2.9%) with breast magnetic resonance imaging. Only the BI-RADS® 4A lesion categories were changed by breast magnetic resonance imaging, and these lesions were pathologically diagnosed as benign. The negative predictive value of breast MRI for BI-RADS® category 4A lesions was calculated as 100%. In all BI-RADS® category 4 lesions, pathologically 4 lesions found to be high risk and 3 lesions found to be malignant. The sensitivity, specificity, positive predictive, and negative predictive value of breast magnetic resonance imaging in BI-RADS® category 4 lesions were calculated as 100, 29.6, 26.9, and 100%, respectively. The area under the ROC curve was calculated 0.648. Breast magnetic resonance imaging is promising to be used as a problem-solving modality in BI-RADS® category 4A breast lesions.     

Clinical magnetic resonance imaging and arthroscopic findings in knees: a comparative prospective study of meniscus anterior cruciate ligament and cartilage lesions

We compared the diagnostic and predictive value of magnetic resonance imaging (MRI) and clinical findings with arthroscopy in 61 knees in a prospective study. In meniscal tears, the accuracy and positive predictive value of MRI was found to be nearly twice that of clinical examination. The sensitivity, specificity, and negative predictive value of MRI were comparable to the figures found in other studies. We recommend MRI as a clarifying diagnostic tool when a clinical examination indicates a lesion of the meniscus. In our study, the clinical relevance of MRI in anterior cruciate ligament lesions and especially in cartilage lesions was more doubtful. The combination of clinical and MRI findings would reduce the number of blank arthroscopies to 5%. MRI is a valuable diagnostic tool in planning the type of anesthesia and treatment, and could significantly reduce the need for a second arthroscopy.Arthroscopy 1998 Mar;14(2):171-5     

Prospective comparison of standard triple assessment and dynamic magnetic resonance imaging of the breast for the evaluation of symptomatic breast lesions

OBJECTIVE: To compare the sensitivity and specificity of the traditional triple assessment of symptomatic breast lesions with contrast-enhanced dynamic magnetic resonance imaging. BACKGROUND: Although triple assessment is currently the gold standard for the assessment of symptomatic breast disease, its specificity is such that open biopsies are still required in many cases to be confident of the diagnosis. Contrast-enhanced dynamic magnetic resonance imaging of the breast represents an alternative diagnostic modality. METHODS: Patients were recruited from the symptomatic breast clinics. If any of the diagnostic modalities suggested malignancy, the lesion was excised. The remaining patients were followed clinically and radiologically. RESULTS: Two hundred eighty-five patients with a mean age of 43 years (range 21 to 77) were recruited. Malignant lesions were excised in 131 patients and benign lesions in 55 patients. The 99 patients who did not undergo surgery were followed clinically and radiologically for a median of 20 months. The sensitivity of each modality was as follows: clinical examination 84%, mammography 87.6%, fine-needle aspiration cytology 79.1%, triple assessment 99.2%, and magnetic resonance imaging 99.2%. In addition, histologically confirmed multifocal disease was detected in 40 patients on magnetic resonance imaging but in only 9 (22.5%) on mammography. The specificity for the diagnosis of benign disease was as follows: clinical examination 83.1%, ultrasound 88.9%, mammography 86.4%, fine-needle aspiration cytology 97%, triple assessment 59.1%, and magnetic resonance imaging 90.9%. CONCLUSION: Contrast-enhanced dynamic magnetic resonance imaging of the breast is as sensitive and more specific than the combined traditional triple assessment for the diagnosis of malignant breast lesions.     

Editorial Commentary: Delphi Expert Consensus Clarifies Evidence-Based Medicine for Shoulder Instability and Bone Loss

Anterior glenohumeral instability with glenoid bone loss is a difficult problem and often requires open procedures with bone block augmentation. The current evidence suggests glenoid bone loss of 20% or more as a cutoff value indicating augmentation. Expert consensus–based techniques, such as the Delphi, clarify evidence-based medicine and allow pooling of expert opinion in a scientific fashion. These methods suggest that 3-dimensional computed tomography should be used to evaluate bone loss, previous dislocations, or failed soft-tissue surgery; Hill–Sachs lesions are poorly quantified by standard imaging; and, in cases with a bone deficit of >20%, glenoid bone graft should be considered. No consensus was reached regarding glenoid track evaluation, magnetic resonance imaging for evaluation of bone loss, safety of arthroscopic Latarjet, remplissage use for Hill–Sachs lesions of less than 30%, indications for a shoulder sling for 4 to 6 weeks after surgery, or postoperative rehabilitation timing and range-of-motion protocols.     

The efficacy of magnetic resonance imaging and ultrasound in detecting disruptions of the forearm interosseous membrane: a cadaver study

The purpose of this study was to examine the efficacy of magnetic resonance imaging (MRI) and ultrasound (US) in determining complete disruptions of the central portion of the forearm interosseous membrane. The midportion of the forearm interosseous ligament was longitudinally incised in 19 fresh-frozen cadaver arms. The specimens were imaged with MRI and US. The MRIs were examined by a hand surgeon, a musculoskeletal radiologist, and a general radiologist, all blinded to the state of the interosseous membrane. The musculoskeletal radiologist and general radiologists read the real-time US images in a consensus fashion. Magnetic resonance imaging showed a 96% accuracy rate, a 100% positive predictive value, a 93% negative predictive value, 93% sensitivity, and 100% specificity. Kappa analysis showed substantial interobserver agreement for MRI. Ultrasound showed a 94% accuracy rate, a 94% positive predictive value, a 100% negative predictive value, 100% sensitivity, and 89% specificity. There was no statistical significance between the accuracy of MRI and US. We conclude that MRI and US imaging should both be considered when forearm interosseous membrane integrity is in question.     

Review article: diagnostic ultrasonography: applications in orthopaedic surgery

Diagnostic ultrasonography of musculoskeletal diseases in the United States has been used most often for detection of rotator cuff tears or developmental dysplasia of the hip. Diagnostic ultrasonography also is useful in imaging the periarticular soft tissues about the knee, hip, ankle, occult pediatric fractures, muscle injury, bone healing, and foreign bodies. Recent technologic improvements have made this imaging modality increasingly more accurate while providing significant benefits over traditional modalities such as magnetic resonance imaging, particularly regarding cost, patient satisfaction, and ease of usage. Increasing use in the future of diagnostic ultrasonography for musculoskeletal conditions is likely as acceptance grows. This review focuses on recent, practical applications of diagnostic ultrasonography of the musculoskeletal system.