Hemophilic arthropathy. A scoring system for magnetic resonance imaging

The aim of this study was to define a system for scoring hemophilic arthropathy (HA) based on MR findings, providing for objective evaluation of the degree of joint involvement and evolution after on-demand administration of FVIII substitutional therapy or prophylactic treatment. A total of 133 MR examinations (89 basal and 44 during follow-up) were performed in 25 patients. Patients were divided in two groups depending on the therapy received and the length of time that the disease had been evolving at the start of the study. Group I was composed of 10 patients with secondary prophylaxis and group II was composed by 15 treated on demand. T1-weighted and T2*-weighted images performed on a 0.5-T unit were prospectively evaluated. The joint involvement was established on a scale of 0 (no abnormalities), I (minimal amount of hemosiderin), II (large amount of hemosiderin and isolated cartilaginous erosion), III (cartilage destruction, bone erosions, and subchondral cysts) to IV (large internal joint derangement, secondary osteoarthritis and/or ankylosis). At basal MR examination, patients of group I showed no abnormalities ( n=28, 75.6%), grade I ( n=3), and grade II ( n=6) of HA. Patients of group II corresponded to MR grades III ( n=21) and IV ( n=11) of HA. The MR follow-up showed improvement in three joints of group I and worsening in 5 joints in group I and 2 joints in group II. Early signs of HA were detected in 10 joints with MR imaging but were underestimated on plain radiographs. Advanced degrees of HA were classified as severe under both imaging techniques. Magnetic resonance is the preferred imaging technique to assess HA. The earliest signs of joint damage, detected by MR, are overlooked by plain radiography. The MR scoring system can be used for evaluating HA. Follow-up MR should be performed to evaluate regression or worsening of the abnormalities, primarily in the case of patients with prophylaxis who usually suffer normal or early joint involvement not detected by other means.     

MR imaging of hemophiliac arthropathy

Magnetic resonance (MR) imaging of the knee was performed in 10 patients with hemophilia. The periarticular and subchondral abnormalities were classified according to the signal intensity from these regions on T1- and T2-weighted pulse sequences. Periarticular abnormalities were detected in 50% of the hemophiliac joints, and fibrous changes were noted in 57% of all the areas of subchondral abnormality. Magnetic resonance imaging identifies periarticular and subchondral abnormalities in patients with hemophilia and may help in monitoring the progress of the disease process.     

Chondromalacia patellae: assessment with MR imaging

Magnetic resonance (MR) images of the posterior patellar hyaline articular cartilage were obtained in 23 subjects to determine if MR imaging could accurately demonstrate the patellar cartilage. Arthroscopy was used as the standard of reference. Three subjects were asymptomatic volunteers. In the remaining 20 who had patellofemoral pain, arthroscopy was performed before MR imaging in seven and afterward in 12; one did not undergo arthroscopy. MR imaging showed focal areas of swelling of the patellar cartilage, focal hypointensity, surface irregularity, areas of thinning, and areas of cartilage loss with exposure of subchondral bone. The surgical findings agreed with those from MR images in all seven patients who underwent arthroscopy before MR imaging and in ten of the 12 who underwent surgery afterward. MR imaging is an accurate means of examining the posterior patellar cartilage and should be considered as an alternative to diagnostic arthroscopy when chondromalacia patellae is suspected.     

Gaucher disease: assessment with MR imaging

The skeletal system, spleen, and liver of five patients with proved Gaucher disease were studied with magnetic resonance (MR) imaging. Homogeneous, low intensity signals resulting from relaxation times different than normal (longer T1 and shorter T2 values) were found in the marrow of long bones, vertebrae, and hips in all patients. In three patients, normal signals were noted in the patella, epiphysis of the knee, and capital femoral epiphysis. In two patients with acute bone pain in the tibial region, a higher signal was received from the tibial marrow. This signal was related to increased accumulation of fluid following an avascular episode. Soft tissues in the same area were also involved. Liver and spleen enlargement was readily visible, especially on coronal images. T1 values of spleen were significantly shorter than normal. MR imaging provides an excellent assessment of the extent of involvement of the liver, spleen, and bone marrow in Gaucher disease.     

Pisotriquetral joint: assessment with MR imaging and MR arthrography

PURPOSE: To evaluate magnetic resonance (MR) imaging and MR arthrographic findings in the pisotriquetral joint (PTJ) and their contribution to assessment of PTJ osteoarthritis. MATERIALS AND METHODS: Images of 22 fresh human cadaveric PTJs were obtained with both conventional and arthrographic MR techniques. The MR appearances of all intraarticular and periarticular structures were analyzed and correlated with anatomic slices. Two readers graded visibility of anatomic structures and severity of joint abnormalities. Differences in the visibility ratings at standard MR imaging and at MR arthrography were calculated. Association between the type of pisiform insertion of ligament or muscle with cartilaginous abnormalities of the PTJ was assessed. The association between cartilaginous lesions and osteoarthritic changes was calculated. RESULTS: The tendon sheath, the fibrous capsule, and cartilaginous surfaces were better visualized at MR arthrography than at MR imaging. Pisohamate and pisometacarpal ligaments were slightly better seen on MR arthrograms. Tendons, muscles, and retinacular structures were well demonstrated at both conventional MR and MR arthrography. Cartilaginous lesions and osteophytes were easily identified and were detected more often in the pisiform bone than in the triquetral bone. Communication of the PTJ with the radiocarpal joint was noted in 18 (82%) of 22 wrists. CONCLUSION: MR imaging and/or MR arthrography allows visualization of all anatomic structures of the PTJ. MR arthrography improves visualization of findings of osteoarthritis.     

Fatty filum terminale: assessment with MR imaging

Five cases of fatty filum terminale were encountered in a retrospective analysis of 332 routine lumbosacral magnetic resonance studies. The T1-weighted and GRASS images were particularly useful in evaluating the filum. An irregularly thickened fatty filum, especially if associated with a low conus, is likely to be pathologic and responsible for a patient's symptoms and signs.     

Juvenile rheumatoid arthritis: assessment with MR imaging

Thirty-three joints of the appendicular skeleton in 15 children with juvenile rheumatoid arthritis were examined with magnetic resonance (MR) imaging to determine if it could demonstrate synovial hypertrophy and status of the articular cartilage. Presumed synovial hypertrophy was seen in 13 joints as masses of varying sizes of low to intermediate signal intensity on T1- and T2-weighted images; sometimes foci of increased signal intensity, most likely due to fluid or inflammation, were seen on T2-weighted images. Probable abnormal articular cartilage was detected in ten joints, and MR imaging also demonstrated epiphyseal overgrowth, bone erosions, joint effusions, and joint space narrowing. Because MR imaging appears to provide an objective method of evaluating both synovial hypertrophy and status of articular cartilage, it may prove to be useful in monitoring progression of juvenile rheumatoid arthritis and response to therapy.     

Hemophilic pseudotumor: spectrum of MR findings

 Objective. To determine the MR imaging appearance of hemophilic pseudotumor (HP) and its clinical implications. Design and patients. Five hemophilic patients (aged 35–77 years) with 12 HPs in various anatomic locations were included in this study. The MR images were retrospectively evaluated for the appearance of the lesions and accompanying abnormalities, as well as their clinical implications. Results and conclusion. MR images of all five patients (12 lesions) showed well-defined masses containing blood clots in various stages of organization surrounded by a fibrous capsule in subcutaneous fat or in intramuscular, interfascial, subperiosteal, and intraosseous locations. Intramuscular HP frequently had mural nodules. This is an almost unique appearance that is somewhat unexpected. MR imaging allowed determination of number, size, and extent of the lesions, evidence of neurovascular involvement, and accompanying musculoskeletal alterations. It is concluded that MR imaging not only is a sensitive and accurate method for detecting and diagnosing HP and providing useful information for therapeutic decision making, but can also be used to assess results of treatment by allowing evaluation of the evolution of blood products, the size of lesions in regions difficult to access by physical examination, and recurrent bleeding within a chronic lesion.     

Hip arthropathy in a patient with primary hemochromatosis: MR imaging findings with pathologic correlation

Arthropathy is a major clinical manifestation in primary hemochromatosis, typically affecting the metacarpophalangeal joints. Hip arthropathy is not uncommon, with radiologic features resembling osteoarthritis or calcium pyrophosphate dihydrate (CPPD) crystal deposition disease. We describe the MR imaging findings of the hip in a patient with severe hip arthropathy and primary hemochromatosis and correlate them with the histopathologic findings. MR imaging showed severe degenerative changes, with large subchondral cysts and subchondral sclerosis in the femoral head and acetabulum. There was conspicuous correlation between MR imaging and pathologic findings of the resected femoral head. However, MR imaging failed to reveal intra-articular iron.     

Neuropathic arthropathy of the foot with and without superimposed osteomyelitis: MR imaging characteristics

PURPOSE: To determine retrospectively the magnetic resonance (MR) findings associated with pedal neuropathic arthropathy with and without superimposed osteomyelitis and to identify any useful discriminating features. MATERIALS AND METHODS: Investigational review board approval was obtained and allowed review of records and images without informed consent. HIPAA compliance was observed. Contrast-enhanced MR images in patients with diabetic neuropathic arthropathy of the foot were examined by two reviewers in consensus. Affected joints were examined for marrow, articular, periarticular, and soft-tissue findings. Presence of superimposed osteomyelitis was documented. A subgroup that had undergone MR before infection was evaluated for comparison; chi(2) and t tests were used to evaluate the associations. RESULTS: Of 128 neuropathic joints in 63 patients (24 female, 39 male; aged 31-78 years), 43 had superimposed osteomyelitis. Effusion was common in all neuropathic joints, but thin rim enhancement was more common in noninfected joints (62% vs 21%, P < .001) and diffuse joint fluid enhancement was more common with infection (47% vs 26%, P = .052). Subluxation, bone proliferation, fragmentation, and erosion were seen in both groups, but intraarticular bodies were more common in noninfected joints (53% vs 12%, P < .001). In the periarticular soft tissues, edema, enhancement, and ulceration were common in both groups. Fluid collections in the soft tissues were more commonly associated with infected joints (95% vs 48%, P < .001) and, when present next to an infected joint, were larger than those next to noninfected neuropathic joints (2.6 cm(2) [range, 0.3-8.6 cm(2)] vs 1.6 cm(2) [range, 1.0-2.4 cm(2)]). Soft-tissue fat replacement (68% vs 36%, P = .002) and sinus tracts (84% vs 0%, P < .001) were also more common with infection. In the marrow, periarticular signal intensity abnormality was common in both groups, but the extent was greater with infection. Subchondral cysts were seen almost exclusively in noninfected joints (76% vs 2%, P < .001). Similar results were obtained in the subgroup of 21 joints (15 patients) with both pre- and postinfection MR images. CONCLUSION: Sinus tract, replacement of soft-tissue fat, fluid collection, and extensive marrow abnormality are MR imaging features indicating superimposed infection. Thin rim enhancement of effusion, presence of subchondral cysts, or intraarticular bodies indicate absence of infection.     

Cardiac tumors: assessment with Gd-DTPA enhanced MR imaging

Previous studies have shown the value of MR imaging for the identification of cardiac masses. The distinction of intramural tumors from normal myocardium may be equivocal because of the similarity of signal intensity between tumor and normal myocardium on ECG-gated SE images. The purpose of this study was to assess the role of Gd-DTPA for improving the contrast between cardiac tumors and myocardium. Four patients with established or suspected cardiac tumors were imaged with a 1.5 T imager. The T1-weighted images (TR = RR interval, TE = 20-30 ms) were obtained before and immediately after the intravenous injection of Gd-DTPA, at a dosage of 0.1 mmol/kg. Tumors were identified in three patients. All tumors were isointense to the myocardium in precontrast images but demonstrated differential enhancement relative to myocardium after the administration of Gd-DTPA. Two tumors were hyperintense relative to myocardium, and the third was mostly hypointense, surrounded by a hyperintense rim. In the remaining case, no tumor was found and the myocardium was homogeneously enhanced on postgadolinium images. Gadolinium DTPA can produce differential enhancement of tumor from normal myocardium and therefore demonstrate intramural masses.     

Fetal posterior fossa volume: assessment with MR imaging

PURPOSE: To retrospectively determine the relationship between posterior fossa volume (PFV) and estimated gestational age (EGA) and/or femur length (FL) during pregnancy for the purpose of developing a normal growth curve. MATERIALS AND METHODS: Advance institutional review board approval was obtained for this HIPAA-compliant study, and the need for parent informed consent was waived. A cross-sectional retrospective study was performed to measure PFV on in vivo magnetic resonance (MR) images obtained in 76 fetuses of 18-36 weeks gestation who had a morphologically normal CNS. Because this was a retrospective series, MR imaging techniques varied slightly, but all fetuses underwent imaging at contiguous 3-5-mm intervals in at least two orthogonal planes, with repetition time msec/echo time msec, 5-12/62-95; number of signals acquired, one; flip angle, 150 degrees -180 degrees; and matrix, 128-192 x 256. Posterior fossa areas were manually traced on half-Fourier rapid acquisition with relaxation enhancement in utero fetal MR images by one observer. PFVs were then calculated by manually summing areas from the contiguous sections and multiplying the total area by the section thickness. An average PFV (APFV) across orthogonal planes was calculated for each fetus, and the relationship between APFV and EGA was mathematically modeled. Coronal, transverse, and sagittal views were compared with correlations and Bland-Altman plots. Two additional observers repeated the measurements for a small subset of fetuses (n = 5). Paired t test analyses were also performed to determine significant differences between sagittal, transverse, and coronal measurements, as well as to determine preliminary intraobserver and interobserver variability of measurements in a subset of cases. RESULTS: The relationship between APFV (in cubic centimeters) and EGA (in weeks) was well described by a single exponential function [APFV = 0.689 exp(EGA/9.10)]. APFV doubling time was 6.31 weeks. Root-mean-square variation of values around the model line was 1.63 cm(3). There was no statistically significant intra- or interobserver variation (P > .16 for all fetuses) at preliminary analysis. No correlation between APFV and FL could be found. CONCLUSION: The normal fetal PFV growth curve generated in this study may have potential as a model for clinical application.     

Pelvic abnormalities in children: assessment with MR imaging

Multiplanar images of 62 pelvic lesions in 58 children and adolescents (aged 7 months to 19 years; mean, 10.6 years) were obtained with 0.3-T magnetic resonance (MR) imaging. Lesions were divided into three categories: congenital anomalies, cystic lesions and fluid collections, and neoplasms. MR demonstrated lesions well in all categories. Midline lesions were best imaged sagittally, and lesions of paired structures, axially. The coronal plane was useful in evaluating the superoinferior extent of lesions and in defining the extent of lymphadenopathy. T1-weighted sequences were sufficient to depict most congenital and cystic lesions. T2-weighted sequences were useful in demonstrating the extent of neoplasms and the position of ectopic gonads. Ultrasonography (US) was also performed in 45 cases. MR and US delineated lesions equally well in 25 cases (55.5%), MR was superior in 19 (42.4%), and US was superior in one (2.2%). Computed tomography (CT) was performed in 13 cases. MR and CT delineated lesions equally well in eight cases (61.5%), MR was superior in four (30.8%), and CT was superior in one (7.7%).     

Cranial postoperative site: assessment with contrast-enhanced MR imaging

To define duration and patterns of postoperative contrast material enhancement, the authors evaluated magnetic resonance (MR) images obtained with gadolinium diethylenetriaminepentaacetic acid (DTPA) in 46 patients who had undergone major intracranial surgery. Intervals between surgery and MR imaging ranged from 1 day to 40 years (median, 1.3 years). Moderate or marked brain and dural enhancement was noted in nearly every patient imaged within 3 months of surgery, but all brain enhancement was gone by 1 year. Abnormal dural enhancement was noted in every patient imaged within 1 year of surgery and in approximately 50% at 1-2 years afterward. One patient had persistent mild enhancement of the dura 40 years after surgery. MR images revealed enhancement in several sites not frequently recognized on computed tomographic (CT) scans. Brain and meningeal enhancement with Gd-DTPA at cranial operative sites was more extensive and persisted much longer than is commonly seen on contrast-enhanced CT scans. Enhancement of the brain or pia mater does not normally last beyond 1 year, but dural enhancement may persist for decades.     

Uterine cervical cancer: assessment with high-field MR imaging

Nineteen patients with histologically proved cervical carcinoma were evaluated with magnetic resonance (MR) imaging. Clinical, MR, and surgical findings were compared to determine accuracy and clinical usefulness of MR in demonstrating mass and extent of disease. MR imaging enabled clear differentiation of corpus uteri, cervix, vagina, uterine ligaments, and tumor. Tumor was demonstrated as a high-intensity mass deforming the low-intensity cervix; the low background intensity of normal structures provided high contrast to the mass. MR imaging accurately demonstrated the tumor in all ten patients with locally advanced cervical carcinoma and showed a normal cervix in nine patients with early cancer. On sagittal images, the shape of corpus uteri, cervix, and vagina, and their relationship to the mass were clearly assessed, with their long axes usually in a single plane. On axial images, assessment of parametrial tumor extension was facilitated by clear definition of the low-intensity cervix and uterine ligaments. Although more study is needed to determine the accuracy of MR in staging, MR is a promising method in evaluating cervical carcinoma.     

Lumbar spine: postoperative assessment with surface-coil MR imaging

A prospective study of 15 patients who were scheduled to undergo various types of lumbar spine surgery was undertaken to assess the postoperative changes observable with magnetic resonance (MR) imaging. Patients underwent imaging preoperatively, immediately postoperatively (1-10 days), and late postoperatively (2-6 months). A retrospective review of MR images obtained in 62 patients who had undergone lumbar surgery but still had low back pain was also conducted. Epidural soft-tissue change and mass effect mimicking preoperative findings were present in nine of 13 patients who underwent laminectomy and diskectomy. Mass effect improved in appearance by the late postoperative period in eight of nine patients. T2-weighted sagittal images were best in demonstrating the site of anulus disruption immediately after diskectomy, which was seen in 11 of 13 patients, and the rent resolved on the late images in eight of ten cases. Sites of foraminotomy were seen as a loss of the normal foraminal fat signal. Extensive soft-tissue changes present in the immediate postoperative period severely limit the usefulness of MR imaging in that period for evaluating persistent symptoms. The exception may be hemorrhage, as its distinctive signal on T1-weighted images makes its identification possible.