Patients with suspected meniscal tears: prevalence of abnormalities seen on MRI of 100 symptomatic and 100 contralateral asymptomatic knees

OBJECTIVE: The purpose of this study was to evaluate the prevalence of MR abnormalities of the knee on the symptomatic and contralateral asymptomatic sides in patients with suspected meniscal tears. SUBJECTS AND METHODS. One hundred patients (mean age, 42.7 years; range, 18-73 years) referred for suspected meniscal tears were prospectively examined with MRI of both knees when the contralateral knee was asymptomatic. The prevalence of various types of meniscal tears and other MR abnormalities was determined. RESULTS: Meniscal tears were found in 57 symptomatic knees and in 36 contralateral asymptomatic knees. In those 57 patients with a meniscal tear on the symptomatic side, the prevalence of asymptomatic tears in the contralateral side was 63% (36/57). Horizontal or oblique meniscal tears were found medially in 32 and laterally in 11 symptomatic knees, and medially in 29 and laterally in eight asymptomatic knees. Radial, vertical, complex, or displaced tears were found medially in 18 and laterally in five symptomatic knees, and medially in five and laterally in none of the asymptomatic knees. Collateral ligament abnormalities were found in 53 symptomatic knees and in six asymptomatic knees. Pericapsular soft-tissue abnormalities were found in 64 symptomatic and in 12 asymptomatic knees. Edema-like bone marrow abnormalities were found in 36 symptomatic and in three asymptomatic knees. CONCLUSION: Horizontal or oblique meniscal tears are frequently encountered in both asymptomatic and symptomatic knees and may not always be related to symptoms. However, radial, vertical, complex, or displaced meniscal tears and abnormalities of the collateral ligaments, pericapsular soft tissues, and bone marrow are found almost exclusively on the symptomatic side and appear to be clinically more meaningful.     

Magnetic resonance imaging in symptomatic Paget's disease

Four patients with symptomatic Paget's disease of the appendicular skeleton were evaluated by magnetic resonance (MR) imaging. The plain film findings in each case were advanced but dissimilar. All patients had progressive symptoms of pain, and one presented with excruciating pain of short duration. The radiographic features included diffuse progressive osteolysis, cortical resorption, insufficiency fractures, bowing, and cortical and trabecular thickening. In three of the patients, MRI was performed to exclude sarcoma, revealing preservation of fatty marrow signal in all phases of Paget's disease except in patients with an acute fracture (demonstrated by MRI) and sarcoma. Small, focal, linear or oval areas of low signal seen against a background of normal marrow signal on short or long TR/ TE do not mimic tumor. These findings suggest that fatty marrow signal is preserved in advanced Paget's disease unless an acute fracture or tumor is present.     

Magnetic resonance imaging of the gallbladder: spectrum of abnormalities

Various pathologies involving the gallbladder can manifest clinically, producing nonspecific clinical symptoms and making diagnosis difficult and challenging. Real-time sonography is the most widely used diagnostic study for the gallbladder and the primary screening examination of choice. With increasing use of magnetic resonance imaging (MRI) and MR cholangiopancreatography (MRCP), gallbladder pathology is frequently seen. Understanding the basic patterns of various disease manifestations and appearance on MRI is the key to making an accurate diagnosis. Given its inherent tissue contrast and contrast sensitivity, MRI in conjunction with MRCP can be a very valuable test in evaluating gallbladder pathology. Gallbladder pathology can be classified into congenital (such as absence), inflammatory (acute, hemorrhagic, and chronic cholecystitis), traumatic, benign (polyps) and malignant tumors (gallbladder carcinoma and lymphoma), and other disease processes can be seen in cholelithiasis, cholesterosis, thickened gallbladder wall, and Mirrizzi syndrome.     

Magnetic resonance imaging of carotid artery abnormalities in patients with sphenoid sinusitis

Sphenoid sinusitis is unusual in children, but when it occurs, it can lead to serious intracranial complications. We show the value of MRI in demonstrating intracranial abnormalities due to sphenoid sinus infection, particularly those involving the internal carotid arteries and cavernous sinuses. We reviewed our imaging experience of sphenoid sinusitis and found four patients with ICA narrowing who had undergone MR evaluation including conventional and diffusion imaging. MR angiography was also performed in three patients to determine the extent of ICA narrowing. Narrowing of ICA was found in the cavernous segment in all patients and in the supraclinoid segment in three. Cerebral infarction was found in two patients. In one patient the cavernous sinus showed hyperintensity on diffusion-weighted images and hypointensity on apparent diffusion coefficient map, suggesting reduced diffusion. Although infrequent in children, sphenoid sinus infection should be considered as a possible cause of intracranial infection, particularly in teenagers. Early recognition of cavernous sinus involvement and ICA narrowing may lead to prompt treatment and hence a more favorable outcome.     

Magnetic resonance imaging of meniscal degeneration in torn menisci: a comparison between anterior cruciate ligament deficient knees and stable knees

Signal anomalies observed in magnetic resonance imaging of the intrameniscal tissue adjacent to the tear were compared between stable knees (group 1, 54 menisci) and anterior cruciate ligament (ACL) deficient knees (group 2, 98 menisci). The histological significance of these signal anomalies was also studied (n = 25). The frequency of intrameniscal signal anomalies adjacent to the tear was significantly lower in ACL-deficient knees than in ACL-stable knees (P = 0.0022). There was a close correlation between the imaging anomalies and the presence of histological lesions (fissures, degeneration) within meniscal tissues adjacent to the tear (sensitivity: 0.95, specificity: 0.60). Our results suggest that the severity of intrameniscal degenerative changes adjacent to the tear are lower in ACL-deficient knees than in ACL-stable knees.     

Magnetic resonance imaging of white matter changes in traumatic leukoencephalopathy

Computed tomography has become a prime method of examination after trauma. We report a case of traumatic leukoencephalopathy detected with high-field strength, heavily T2-weighted magnetic resonance imaging in a patient with minimal computed tomography findings.     

Magnetic resonance imaging of the femoral trochlea: evaluation of anatomical landmarks and grading articular cartilage in cadaveric knees

Purpose The purpose of the study was to define magnetic resonance imaging (MRI) findings before and after contrast medium opacification of the knee joint in cadaveric specimens to demonstrate anatomical landmarks of the trochlear surface in relation to the neighboring structures, and to evaluate different MRI sequences in the detection of cartilage defects of the trochlear and patellar surface of the knee. Materials and Methods The morphology and relationship of the proximal trochlear surface to the prefemoral fat of the distal femur were investigated by use of different MR sequences before and after intra-articular gadolinium administration into the knee joint in ten cadaveric knees. Anatomic sections were subsequently obtained. In addition, evaluation of the articular surface of the trochlea was performed by two independent observers. The cartilage surfaces were graded using a 2-point system, and results were compared with macroscopic findings. Results Of 40 cartilage surfaces evaluated, histopathologic findings showed 9 normal surfaces, 20 containing partial-thickness defects, and 11 containing full-thickness defects. Compared with macroscopic data, sensitivity of MR sequences for the two reviewers was between 17 and 90%; specificity, 75 and 100%; positive predictive value, 75 and 100%; negative predictive value, 20 and 100%, depending on patellar or trochlea lesions. Interobserver variability for the presence of disease, which was measured using the kappa statistic, was dependent on the MR sequence used between 0.243 and 0.851. Conclusion Magnetic resonance imaging sequences can be used to evaluate the cartilage of the trochlear surface with less accuracy when compared with the results of grading the articular cartilage of the patella.     

Magnetic resonance imaging in paralysis of the upper limb of traumatic origin

We have used magnetic resonance imaging in addition to the other imaging techniques for the examination of 31 patients with traumatic upper limb paralysis. The therapeutic indications of traumatic brachial plexus paralysis depend on the early and precise assessment of the lesions. Computed tomography with a contrast injection at a lumbar level opacifying the subarachnoid spaces provides a morphological study of the canal, spine and nerve roots and of container-contents relationships. In our experience, the diagnostic reliability for the detection of intraspinal radicular lesions is 86%. A study in all 3 spatial planes is possible with MRI with T1- and T2-weighted or gradient echo sequences. The reliability of the technique for the diagnosis of meningoceles in the detection of nerve root avulsion is similar to that of CT (85%). The excellent spatial resolution and natural high contrast allow following the nerve roots in their extraspinal course and determining the site of nerve trunk rupture (50%). The use of oblique and double-obliquity sections should yet improve these results. These first results lead us to proposing magnetic resonance imaging for the exploration of traumatic lesions of the brachial plexus. This nonagressive, more precise and more complete assessment of the lesions certainly has a significant influence on therapeutic choice.     

Magnetic resonance imaging in patients with panhypopituitarism

Primary panhypopituitarism consists of functional deficiency of the anterior pituitary lobe, which appears during infancy or adolescence. The magnetic resonance findings in 10 patients with a history of primary hopopituitarism are presented. The findings include: reduced pituitary size in all cases: partially (8 cases) or totally (2 cases) empty sella; thin (4 cases), partially visible (3 cases) or absent (2 cases) pituitary stalk; absence of the posterior lobe in 9 cases: bright spot corresponding to an ectopic posterior lobe in 8 cases. These findings are similar to those already reported in pituitary dwarfism and may help under-genesis of the pathogenesis of the disease: which seems to he related to a pituitary stalk lesion.     

Magnetic resonance imaging of tendon and ligament abnormalities: Part II. Pelvis and lower extremities

Magnetic resonance imaging (MRI) has provided an ideal means, unmatched by other preexisting modalities, of examining musculoskeletal abnormalities, particularly those involving tendons and ligaments in the lower extremities. Lack of motion artifact, convenience of application of surface coil, and absence of overlying structures have made the lower extremities ideally suited to MRI. In addition, the abundance of adjacent adipose tissue provides a superb contrast background. Although evaluation of trauma remains the most common reason for MRI examination, many other conditions may also affect tendons and ligaments. As in other soft-tissue, chondral, and osteochondral lesions, MRI provides exquisite details of abnormalities in these structures. Part II of this review systematically reviews the abnormalities of tendons and ligaments in the pelvis and lower extremities.     

Magnetic resonance imaging of tendon and ligament abnormalities: Part I. Spine and upper extremities

Magnetic resonance imaging (MRI) has proven to be an ideal technique for evaluating tendons and ligaments, which, because of their fibrous structure, have a low signal intensity on all sequences. Trauma and a wide variety of other conditions cause aberrations in the normal appearance of these structures, ranging from minor alterations in shape, size, appearance, and continuity to various changes in signal intensity within the tendon, tendon sheath, and ligament on different sequences. The purpose of this paper is to review MRI findings in patients with abnormalities of tendons and ligaments in the spine and upper extremities.     

Magnetic resonance: perfusion and diffusion imaging

Summary The use of magnetic resonance imaging to detect normal and pathological problems of perfusion and diffusion is reviewed. Motion sensitised spin-echo images can be used to detect changes in slow flow velocity within a voxel (intravoxel coherent motion (IVCM) as well as intravoxel incoherent motion (IVIM) effects attributable to both diffusion and perfusion. Changes have been identified in a variety of brain diseases in the absence of changes in conventional images but the techniques are very vulnerable to motion artefact of all types. More rapid and more sensitive approaches using steady state free precision and echo-planer imaging are being investigated. Anisotropic diffusion imaging enables white matter tracts to be demonstrated within the brain and spinal cord as a function of their direction because diffusion of water across axons is much more restricted than it is along them. This technique provides a unique method for localisation of lesions and displays obvious changes in disease in which diffusion becomes less restricted.     

Patellofemoral evaluation with magnetic resonance imaging in 51 knees of asymptomatic subjects

Purpose  

The objective of this study is to evaluate patellofemoral joint imaging on magnetic resonance imaging (MRI) in asymptomatic subjects to assess normal values and to test statistical correlation and reliability of MRI scan.     

Magnetic resonance imaging of the elbow. Part I: Normal anatomy,imaging technique,and osseous abnormalities

Part I of this comprehensive review on magnetic resonance imaging of the elbow discusses normal elbow anatomy and the technical factors involved in obtaining high-quality magnetic resonance images of the elbow. Part I also discusses the role of magnetic resonance imaging in evaluating patients with osseous abnormalities of the elbow. With proper patient positioning and imaging technique, magnetic resonance imaging can yield high-quality multiplanar images which are useful in evaluating the osseous structures of the elbow. Magnetic resonance imaging can detect early osteochondritis dissecans of the capitellum and can be used to evaluate the size, location, stability, and viability of the osteochondritis dissecans fragment. Magnetic resonance imaging can detect early stress injury to the proximal ulna in athletes. Magnetic resonance imaging can detect radiographically occult fractures of the elbow in both children and adults. Magnetic resonance imaging is also useful in children to further evaluate elbow fractures which are detected on plain-film radiographs.Part II of this review can be found at:     

Magnetic resonance imaging of posterior cruciate ligament injuries: a new classification of traumatic tears

PURPOSE: The aim of our study was to propose a new classification of acute posterior ligament (PCL) injuries based on magnetic resonance imaging (MRI). MATERIALS AND METHODS: Using MRI, we reviewed 220 patients presenting an acute posterior ligament injury. The MRI exam was performed on a 0.2-Tesla (T) magnet and a 1.5-T magnet using T1-weighted spin echo (SE), T2-weighted SE and fat-suppression scans [short-tau inversion recovery (STIR)] in axial, sagittal and coronal planes. In no case was paramagnetic contrast agent injected. RESULTS: Twenty-five per cent of patients were identified as having type I lesions and another 30% as having type II lesions according to the Gross classification. Out of 77 patients, 35% of the whole sample, 37 had a tear of the posteromedial fascicle (type II lesion), and the remaining 40 had anterolateral fascicle tears (type III). In 10% of cases, the ligaments appeared completely interrupted, and these were classified as type IV lesions. CONCLUSIONS: T1-weighted SE sequences need to be integrated with T2-weighted and STIR sequences to detect the real extent of the remaining fascicle. The MRI exam could thus be able to provide a qualitative evaluation of PCL injuries and establish how the injury compromises joint stability.     

Magnetic resonance imaging of temporomandibular disorders: classification, prevalence and interpretation of disc displacement and deformation

AIM: To analyse the prevalence of disc displacements and deformations from MRI of symptomatic temporomandibular disorders (TMD). METHODS: The study was conducted retrospectively on 192 joints of 98 patients (67 females, 31 males, mean age 29 years), who had undergone bilateral MRI (except for four who had unilateral) in the sagittal (both open and closed mouth) and coronal (closed mouth only) planes. These displacements were subdivided into static (complete anterior and posterior, partial anterolateral and anteromedial, sideways lateral and medial, anterolateral and anteromedial rotational) and dynamic (with reduction, without reduction, with incomplete reduction; non-determinable). Disc deformations were subdivided into: enlargement of the posterior band, reversed biconcave shape, biplanar (flattened) and biconvex shape. RESULTS: Eighty per cent of patients had bilateral displacement, 15% unilateral and 5% a normally positioned disc. Complete anterior displacement was the commonest and sideways the rarest. Reduction was present in 58% of disc displacements, no reduction in 26%, incomplete reduction in 4%, while in the remaining 12%, it could not be determined. Rotational displacement was the most likely to feature reduction and sideways the least. Temporomandibular joints with no reduction were closely correlated with bone lesions. The most frequent deformation was biplanar and the rarest enlargement of the posterior band. CONCLUSIONS: There was a high prevalence of displacements and deformations. While they do not appear to be significant in inducing pain, they can predispose to the onset of osteoarthrosis.     

Magnetic resonance imaging and diffusion-weighted imaging in methylmalonic acidemia

Methylmalonic acidemia (MMA) is an inborn disorder of amino acid metabolism, often presenting with neurological symptoms. We present the results of magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) of the brain in a 16-month-old male patient with classic neurological and laboratory findings for MMA. MRI demonstrated the hyperintensity within globi pallidi both on T2-weighted image and DWI during the acute episode of metabolic acidosis.