MR imaging of the knee in marathon runners before and after competition

Objective. To evaluate the findings in MRI-studies of the knee in recreational long-distance runners after competition and to assess the reversibility of the findings. Design and patients. Eight recreational long-distance runners underwent MRI studies of the knee before, immediately after and 6–8 weeks after taking part in the Vienna City Marathon. The studies were evaluated regarding alterations of pre-existing lesions and new pathological findings. Results. In six runners without major pre-existing alterations no negative effects were experienced. In one runner with pre-existing grade III alterations of the menisci, signs of progressive osteoarthritis were experienced 2 months after the competition. In all other cases increased meniscal signal alterations and minor signal changes in the bone marrow after the race were transitory. Conclusion. In healthy individuals no negative long-term-effects were experienced. Pre-existing high-grade lesions of the menisci might be a predisposing risk for osteoarthritis, triggered by the stress of long-distance running. Received: 17 February 2000 Revision requested: 13 June 2000 Revision received: 21 August 2000 Accepted: 9 September 2000     

Soft tissue osteosarcoma with telangiectatic features: MR imaging findings in two cases

Extraskeletal osteosarcomas are rare tumors, and the telangiectatic variety is the least common histological variety in this group. This report describes the clinical and MR imaging findings in two cases arising in the pretibial soft tissues. Both tumors demonstrated marked inhomogeneity with T2-weighted spin echo and STIR sequences. One of the tumors revealed numerous fluid levels within the lesion. A review of the MRI features of these tumors is provided. Osteosarcoma with telangiectatic features should be considered in the differential diagnosis of a soft tissue mass with fluid-fluid levels in patients 40 years of age or older.     

Magnetic resonance imaging in the evaluation of ligament injuries

Magnetic resonance imaging has had a dramatic effect on the means by which we diagnose ligament injuries. Tears resulting from either acute trauma or overuse can be detected noninvasively, directing appropriate therapy be it conservative or surgical. For the elite athlete, earlier diagnosis leads to earlier intervention, or alternatively, a normal MRI examination can result in an earlier return to play. While MRI is accepted for the diagnosis of certain injuries such as complete tears of the cruciate ligaments of the knee, other injuries, such as partial cruciate ligament tears or tears of the intercarpal ligaments of the wrist, remain controversial. Received: 4 August 1998 Revision requested: 1 October 1998 Revision received: 23 October 1998 Accepted: 29 October 1998     

Unsuspected metastases presenting as solitary soft tissue lesions: a fourteen-year review

Objective. To describe a series of patients with no known primary malignancy who presented with a solitary unsuspected soft tissue metastasis masquerading as a soft tissue sarcoma, and secondarily to describe the imaging appearance of these lesions. Design. Records of two academic hospitals with active orthopedic oncology services were reviewed for patients meeting the above criteria. Clinical charts were examined, and the imaging appearance of the soft tissue lesions retrospectively reviewed. Patients. Of 1421 patients examined for soft tissue lesions, 11 were found who met the above criteria. Results. Of the 11 patients whose initial presentation was a solitary soft tissue metastasis, eight were found to have a primary lung cancer, two were diagnosed with adenocarcinoma of unknown primary, and adenocarcinoma of the colon was discovered in the remaining patient. Conclusions. The clinical presentation of a solitary soft tissue metastasis without a known primary malignancy is a rare occurrence, with an incidence of approximately 0.8%. Lung cancer is the primary neoplasm in a high percentage of these cases. Received: 13 Oktober 1999 Revision requested: December 1999 Revision received: 25 January 2000 Accepted: 28 January 2000     

Regional bone changes in deep soft tissue hemangiomas: radiographic and MR features

Objective. To evaluate changes in bone adjacent to deep soft tissue hemangiomas of the extremities. Design and patients. We retrospectively reviewed the plain films of 115 patients with histologically proven deep soft tissue hemangiomas of the extremities. The length and pattern of the bone changes were analyzed and correlated with the MRI examination (n=55) and surgical findings. Results. Plain film studies demonstrated reactive bone changes adjacent to the deep soft tissue hemangiomas in 24 (21%) patients and phleboliths in 23 (20%) patients. The results of plain film analysis revealed a wide spectrum of regional bone changes adjacent to the hemangiomas, including periosteal reactions (16%), regional osteopenia (1%), cortical erosion (3%), bony overgrowth (3%), coarsening of the trabeculae (5%), and a combination of the above changes (4%). The length of the reactive changes corresponded approximately to the size of the hemangioma in 70% and was longer than the largest dimension of the hemangioma in 30%. Of the 55 patients studied with MRI, 39 (71%) patients had normal bones and 16 (29%) had bone changes. Conclusion. Deep soft tissue hemangiomas may cause changes in adjacent bones. Familiarity with the pattern of reactive bone changes may help to avoid misdiagnosis.     

膝关节韧带损伤的MRI诊断

目的:探讨膝关节韧带损伤的MRI表现及诊断价值。方法:36例临床怀疑膝关节损伤的患者于关节镜及手术前行MRI检查,以关节镜结果作为金标准,前瞻性分析膝关节韧带损伤的MRI表现及诊断价值。结果:关节镜证实前交叉韧带损伤21例,其中完全撕裂15例,部分撕裂6例,后交叉韧带损伤12例,正常患者15例。MRI诊断前交叉韧带损伤的敏感度为95.2%,特异度为80%,准确度为88.9%;诊断后交叉韧带损伤的敏感度为100%,特异度为95.8%,准确度为97.2%。结论:MR1是诊断膝关节韧带损伤的理想检查方法,具有较高的临床应用价值。     

MRI of meniscal bucket-handle tears

Objective. A meniscal bucket-handle tear is a tear with an attached fragment displaced from the meniscus of the knee joint. Low sensitivity of MRI for detection of bucket-handle tears (64% as compared with arthroscopy) has been reported previously. We report increased sensitivity for detecting bucket-handle tears with the use of coronal short tau inversion recovery (STIR) images. Design and patients. Three hundred and twenty-seven patients who had MRI of the knee between October 1994 and December 1996 and subsequently underwent arthroscopy were included in the study. We prospectively and retrospectively reviewed the MR examinations of the 30 patients with arthroscopically proven bucket-handle tears. Each of two observers examined each scan for the three traditional findings of bucket-handle tears: a double posterior cruciate ligament sign, a flipped meniscus sign and/or a fragment in the intercondylar notch. We also assessed STIR images in the coronal plane through the menisci looking for an area of increased signal within either meniscus with a displaced meniscal fragment. Results. By using four criteria for diagnosis of meniscal bucket-handle tears, our overall sensitivity compared with arthroscopy was 93% (28 of 30 meniscal bucket-handle tears seen at arthroscopy were detected by MRI). The meniscal fragment was well visualized in all 28 cases on coronal STIR images. The double posterior cruciate ligament sign was seen in 8 of 30 cases, the flipped meniscus was seen in 10 of 30 cases and a fragment in the intercondylar notch was seen in 18 of 30 cases. Conclusion. By using four criteria for diagnosis of bucket-handle tears, overall diagnostic sensitivity of MRI compared with arthroscopy increased from the previously reported 64% to 93%. Coronal STIR images are useful for detecting small meniscal bucket-handle tears.     

MRI对膝关节前交叉韧带损伤的诊断

目的 研究正常和损伤的膝关节前交叉韧带的MRI表现。方法 回顾性分析16例前交叉韧带正常和19例前交叉韧带损伤的MRI表现。结果 正常的前交叉韧带在矢状位上呈一连续笔直的T1WI、T2WI均为低信号的带状影。前交叉韧带损伤的MRI表现为韧带连续性中断4例（韧带内形成假瘤1例）,韧带外形不规则4例、韧带水平走向2例和韧带信号增高9例。结论 MRI是一种首选的诊断前交叉韧带损伤的非创伤性检查方法。     

Ultrasound of the knee

Ultrasound is emerging as a viable imaging modality in the diagnosis and assessment of the musculoskeletal system. Advantages of ultrasound include its easy availability and multiplanar capability, as well as economic advantages. Unlike magnetic resonance imaging, ultrasound demonstrates the fibrillar microanatomy of tendons, ligaments and muscles, enhancing its diagnostic capability. The ability to compress, dynamically assess structures and compare easily with the contralateral side is advantageous. The patient’s exact point of clinical tenderness can be correlated with underlying anatomical structures and associated pathology. The main strength of knee ultrasound is the assessment of para-articular disease. The specific structures best suited for ultrasound assessment include tendons, muscles and ligaments, as well as periarticular soft tissue masses. Joint effusions, synovial thickening, bursal fluid collections, intra-articular loose bodies, ganglion cysts, ligament and tendons tears, tendonitis and occult fractures can be diagnosed. With experience, ultrasound is a time-efficient, economical imaging tool for assessment of the knee. Received: 28 November 2000 Revision requested: 26 January 2001 Revision received: 10 April 2001 Accepted: 10 April 2001     

Chondrocalcinosis of the hyaline cartilage of the knee: MRI manifestations

Purpose. To determine the ability of MRI to detect the presence of crystals of calcium pyrophosphate in the articular cartilage of the knee. Design and patients. The MR studies of 12 knees (11 cases) were reviewed retrospectively and correlated with radiographs (12 cases) and the findings at arthroscopy (2 cases) and surgery (1 case). A total of 72 articular surfaces were evaluated. Radiographic, surgical or arthroscopic demonstration of chondrocalcinosis was used as the gold standard. Additionally, two fragments of the knee of a patient who underwent total knee replacement and demonstrated extensive chondrocalcinosis were studied with radiography and MRI using spin-echo T1-, T2- and proton-density-weighted images as well as two- and three-dimensional fat saturation (2D and 3D Fat Sat) gradient recalled echo (GRE) and STIR sequences. Results. MRI revealed multiple hypointense foci within the articular cartilage in 34 articular surfaces, better shown on 2D and 3D GRE sequences. Radiographs showed 12 articular surfaces with chondrocalcinosis. In three cases with arthroscopic or surgical correlation, MRI demonstrated more diffuse involvement of the articular cartilage than did the radiographs. The 3D Fat Sat GRE sequences were the best for demonstrating articular calcification in vitro. In no case was meniscal calcification identified with MRI. Hyperintense halos around some of the calcifications were seen on the MR images. Conclusion. MRI can depict articular cartilage calcification as hypointense foci using GRE techniques. Differential diagnosis includes loose bodies, post-surgical changes, marginal osteophytes and hemosiderin deposition.     

MRI in assessment of sports related knee injuries

Purpose

To investigate the accuracy of MRI in assessment of sports related knee injuries.

Materials and methods

From August 2012 to March 2013 thirty patients referred for sports related knee pain have been included in this study. Patients were subjected to a dedicated MR knee study and correlated knee arthroscopy and surgery.

Results

The study included thirty patients complaining of sports related knee pain, only 5 patients (16.6%) were with normal MRI findings and 25 patients (83.4%) were with abnormal MRI findings. Among the 25 patients who had injuries of their knees, 15 patients (60%) had ACL injuries, 2 patients (8%) had PCL injuries, 10 patients (40%) had meniscal injuries, 8 patients (32%) had collateral ligament injuries, 5 patients (20%) had bone injuries and 2 patients (8%) had muscular injuries. Only 7 patients (28%) were represented with isolated injury and 18 patients (72%) were represented with combined injuries. In correlation with arthroscopies and surgeries, morphological analysis was true-positive in 23 (92%) patients of the 25 injured patients, and true-negative in 3 (60%) patients of the 5 normal patients. Morphological analysis revealed overall 92% sensitivity and 60% specificity. Regarding the 15 patients who had ACL injuries, 13 patients (86.6%) were true-positive and 8 patients (80%) of the 10 patients who had meniscal injuries were true-positive.

Conclusion

MRI represents the optimal imaging tool in the evaluation of the sports related knee injuries, which has been shown to be an accurate and non invasive method of diagnosing ligament, meniscal, cartilage and muscular knee injuries.     

Chondromyxoid fibroma of the acromium with soft tissue extension

Chondromyxoid fibroma is an unusual, benign tumor of cartilaginous origin and represents less than 1% of all primary bone tumors. It usually involves the long bones around the knee joint or the flat bones of the pelvis or ribs. Soft tissue extension is also thought to be rare in these lesions. They are usually eccentrically located in the metaphyses of the long bones and centrally in the flat bones. The radiographic appearances are characteristically those of a single, lytic lesion with lobulated margins, septations, cortical expansion and a sclerotic rim. Histologically, they display a lobulated pattern with spindle-shaped cells lying within a myxoid matrix with areas of hyaline cartilage. The differential diagnosis includes giant cell tumor, chondroblastoma or enchondroma as well as chondrosarcoma. The rarity of these lesions may render the diagnosis difficult to make, especially when the lesion involves an unusual site such as the acromium. Received: 21 June 1999 Revision requested: 27 September 1999 Revision received: 27 October 1999 Accepted: 28 October 1999     

Intra-articular lipoma with osteochondroid metaplasia in the knee joint

We describe a case of lipoma with osteochondroid metaplasia in the knee joint. Although the location of the lesion and radiographic findings were unusual, computed tomography and magnetic resonance imaging were useful in characterizing adipose, cartilaginous and osseous tissue components within the lesion. Received: 12 October 2000 Revision requested: 3 November 2000 Revision received: 23 December 2000 Accepted: 28 December 2000     

Anterior approach for knee arthrography

Objective. To develop a new method of magnetic resonance arthrography (MRA) of the knee using an anterior approach analogous to the portals used for knee arthroscopy. Design. An anterior approach to the knee joint was devised mimicking anterior portals used for knee arthroscopy. Seven patients scheduled for routine knee MRA were placed in a decubitus position and under fluoroscopic guidance a needle was advanced from a position adjacent to the patellar tendon into the knee joint. After confirmation of the needle tip location, a dilute gadolinium solution was injected. Results and conclusion. All the arthrograms were technically successful. The anterior approach to knee MRA has greater technical ease than the traditional approach with little patient discomfort. Received: 18 December 2000 Accepted: 16 January 2001     

Alveolar soft part sarcoma: MR and angiographic findings

Objective. To present the MR and angiographic findings of alveolar soft part sarcoma (ASPS). Design and patients. MR examinations (12 tumors of 10 patients) of ASPS performed at multiple hospitals were retrospectively reviewed. The tumors were found in the thigh (n=4), lower leg (n=4), femur (n=2, local metastasis), scalp (n=1) and arm (n=1). The MR signal characteristics including signal intensity, homogeneity and signal void of lesions and bony invasion including direct invasion or local metastasis were evaluated. Angiographic findings (n=4) and post-embolotherapy follow-up MR imaging (n=2) findings were also assessed. Results. Local bony metastasis was found in two cases. Seven tumors showed heterogeneous high signal intensity on T1- and T2-weighted images with good enhancement. One tumor had a very high signal on T1-weighted images. Eight tumors (67%) showed numerous signal voids in or near the tumors. All four angiographic studies showed numerous enlarged vessels, arteriovenous shunts and delayed washout. Two cases mimicked arteriovenous malformations on angiographic studies but MR images demonstrated solid soft tissue components as well as tortuous vessels. Conclusions. High signal on T1-weighted image and numerous signal voids are highly suggestive of ASPS, although they are not universal as has been suggested and arteriovenous malformation should be included in the differential diagnosis. Local bony metastases in ASPS were seen in two cases and should be carefully investigated. Received: 12 April 2000 Revision requested: 27 June 2000, 8 August 2000 Revision received: 2 August 2000, 21 August 2000 Accepted: 22 August 2000     

Intra-articular regional migratory osteoporosis of the knee

We report a case of lntra-articular regional migratory osteoporosis of the knee in a 53-year-old man. The case demonstrates an unusual pattern of migration of the marrow edema within the knee joint. This phenomenon has received scant attention in the radiological literature. Received: 9 July 1999 Revision requested: 24 August 1999 Revision received: 6 October 1999 Accepted: 8 October 1999     

Liposarcoma of soft tissue: MRI findings with pathologic correlation

 Objective. To evaluate the MRI findings of liposarcomas of different histologic types and correlate these with the histopathologic features. Design. The MR images of seven liposarcomas were reviewed retrospectively to assess the tumor size, location, margination, signal characteristics and enhancement patterns in different histologic types. Patients. Seven liposarcomas comprising three well-differentiated, two myxoid and two pleomorphic types were evaluated. Results and conclusion. All tumors showed well-defined and mostly lobulated margins. The well-differentiated liposarcomas were composed mainly of fat with septations or nodules, were hyperintense on T2-weighted images, and demonstrated faint enhancement or no enhancement following intravenous contrast. Myxoid liposarcomas were homogeneous or mildly heterogeneous and a pseudocapsule was present in one case. Pleomorphic types showed a markedly heterogeneous internal structure. Both myxoid and pleomorphic lesions-showed moderate or marked heterogeneous enhancement after contrast administration. Well-differentiated liposarcomas may be differentiated from other types of the tumor by their largely lipomatous appearance. The malignancy grade increases in parallel with tumor heterogeneity and contrast enhancement.     

Radiography in osteoarthritis of the knee

Osteoarthritis (OA) is a multifactorial process affecting cartilage and subchondral bone. Conventional radiographs are inexpensive and readily available. The increased knowledge with regard to interpreting weightbearing radiographs of the tibiofemoral joint and axial radiographs of the patellofemoral joint will enable these examinations to remain competitive techniques compared with more expensive and sophisticated methods, such as MR imaging, when investigating knee pain to establish the diagnosis and the severity of OA. Received: 21 May 1999 Revision requested: 13 July 1999 Revision received: 9 August 1999 Accepted: 12 August 1999     

Castleman’s disease of the erector spinae muscle

Castleman’s disease, angio-follicular lymph node hyperplasia, is a relatively rare benign tumour. It typically arises in the mediastinum. We report a unique case arising in the erector spinae muscle. The case demonstrates the importance of radiological investigation and embolisation prior to obtaining a tissue diagnosis and subsequent surgical excision.     

MRI of the knee: value of short echo time fast spin-echo using high performance gradients versus conventional spin-echo imaging for the detection of meniscal tears

Objective. Fast spin-echo (FSE) sequences reduce imaging time compared with conventional spin-echo (CSE) sequences, but may result in blurring. High-performance gradients permit shorter interecho spacing and use of the second echo as the effective TE (20 ms); both improvements reduce blurring. This randomized observer study compared a short TE, second-echo FSE sequence obtained using high-performance gradients and a CSE sequence with similar TR/TE for the detection of meniscal tears in the knee. Design and patients. One hundred consecutive MR examinations of the knee using FSE and CSE sequences at 1.5 T were evaluated. The FSE sequence used an effective TE of 20 ms (centered on the second echo at 2 times minimal interecho spacing) and an echo train length of 4. FSE and CSE parameters were otherwise similar. Four independent, masked readers reviewed randomized sagittal FSE and CSE sequences. Results. Cases were assessed for the presence or absence of meniscal tears and, if present, whether tears were medial or lateral and anterior or posterior. Sequence concordance was 93.5% (1496 of 1600 meniscal segments); the intermethod kappa value was 0.78. Sequence quality was graded from 1 to 5. Average quality of CSE images was slightly but statistically significantly preferred by three of the four readers. Conclusion. There was no statistically significant difference between CSE imaging and FSE imaging centered on the second echo (20 ms) using high-performance gradients for the detection of meniscal tears in the knee. There was a small preference for the quality of CSE images. Received: 22 July 1999 Revision requested: 27 October 1999 Revision received: 7 February 2000 Accepted: 21 March 2000