Uterine junctional zone: correlation between histologic findings and MR imaging.

Uterine zonal anatomy as visualized on T2-weighted (repetition time, 2,500 msec; echo time, 80 msec) magnetic resonance (MR) images consists of a high-intensity central (endometrial) zone, a subjacent low-intensity junctional zone of myometrium, a moderately intense zone of myometrium, and a thin, low-intensity subserosal zone of myometrium. To better define the histologic correlates of these diagnostically significant zones, T2-weighted MR images of 17 in vivo and 13 extirpated human uteri were compared with histologic sections of 17 uteri stained with hematoxylin-eosin, Mallory trichrome, and immunofluorescence staining for actin. Morphometric and electron microscopic observations of uterine surgical specimens were also made. The observations indicate that both the junctional zone and the subserosal zone consist of compact smooth muscle fibers with little extracellular matrix compared with the myometrium proper. Also, the junctional zone is divided into a compact region and a transitional region. The compact region correlates well with the hypointense MR appearance of the junctional zone.     

Bone marrow MR imaging findings in disuse osteoporosis

Objective  

To demonstrate MR imaging findings in the cortical and trabecular bone as well as marrow changes in patients with disuse osteoporosis (DO).     

Bone marrow changes in beta-thalassemia major: quantitative MR imaging findings and correlation with iron stores

The purpose of this study is to describe the MR imaging features of bone marrow in beta-thalassemia major and investigate their relation to ferritin, liver and spleen siderosis. Spinal bone marrow was prospectively assessed on abdominal MR studies of 40 transfused beta-thalassemic patients and 15 controls using T1-w, Pd, T2*-w Gradient Echo (GRE) and T1-w turbo Spin Echo (TSE) sequences. Signal intensity (SI) ratios of liver, spleen and bone marrow to paraspinous muscles (L/M, S/M, B/M respectively) and the respective T2 relaxation rates (1/T2) were calculated. Serum ferritin levels were recorded. Bone marrow hypointensity in at least T2*-w GRE sequence was noted in 29/40 (72.5%) patients. Eleven/40 patients exhibited normal B/M on all MR sequences. Five/40 patients had normal B/M and low L/M. B/M correlated with L/M in T1-w TSE sequence only (r = 0.471, p = 0.05). B/M correlated with S/M and mean ferritin values in all sequences (r > 0.489, p < 0.01 and r  >  − 0.496, p < 0.03 respectively). Marrow 1/T2 did not correlate with ferritin values or liver and spleen 1/T2. B/M in transfused beta-thalassemic patients is related to splenic siderosis and ferritin levels. Although marrow is usually hypointense, it may occasionally display normal SI coexisting with liver hypointensity, a pattern typical of primary hemochromatosis.     

Meniscal changes in the elderly: correlation of MR imaging and histologic findings.

In elderly patients, degenerative changes of the meniscus are common and may mimic a tear. The magnetic resonance (MR) image findings of 179 meniscal sections in 20 cadaver knees were correlated with the histologic and gross pathologic findings. The sensitivity of standard T1-weighted spin-echo images and their corresponding meniscal windows in depicting meniscal tears was 80.6%, specificity was 72.4%, and accuracy was 76.7%. These results are not as good as results reported previously. A major difficulty is the occurrence of grade 3 meniscal signal intensity and diffuse intrameniscal signal intensity in torn and intact menisci. MR imaging in elderly patients, however, is still useful in the diagnosis of meniscal abnormalities. Normal low signal intensity depicted within a meniscus at MR imaging and changes in grades 1 and 2 intrameniscal signal intensity are reliable signs of an intact meniscal surface. Grade 3 and diffuse meniscal signal intensities do not allow a specific diagnosis; menisci with these characteristics should be described as degenerated with a high probability of a tear.     

Bone marrow edema of the hip: MR findings after core decompression.

Magnetic resonance imaging is an extremely sensitive technique for evaluation of bone marrow changes at an early stage of avascular necrosis (AVN) of the hip. We therefore examined 11 painful hips whose clinical symptoms led us to suspect idiopathic AVN. The radiographs of all of these either were normal or demonstrated a minimal decrease in radiodensity. Magnetic resonance demonstrated diffuse signal loss of the bone marrow at short TR/TE images of the femoral head in all hips, with various extensions in the head, neck, and intertrochanteric area. These regions turned iso- to hyperintense on long TR/TE images compatible with bone marrow edema (BME). Focal abnormalities characteristic for AVN were not seen in any of the cases. Radionuclide studies performed in six cases were positive. All patients underwent core decompression treatment. Hydrostatic bone marrow pressure measurement and intraosseous venography were positive in five cases when measured. Histology available in eight cases confirmed the presence of BME. Furthermore, the bone changes corresponded to those of early AVN. Follow-up examinations after core decompression with MR showed normal signal intensity in all cases. Magnetic resonance represents a viable diagnostic tool for BME and can monitor the therapeutic success of core decompression. Whether BME of the femoral head constitutes a distinct transient syndrome or represents an early form of AVN is controversial at present. Our findings support those who believe that BME may represent an initial stage of idiopathic AVN.     

Lumbar disk herniation: correlation of histologic findings with marrow signal intensity changes in vertebral endplates at MR imaging

PURPOSE: To compare findings at preoperative magnetic resonance (MR) imaging with data for tissue composition of herniated disks in patients after microsurgical removal of herniated material. MATERIALS AND METHODS: Fifty-one patients underwent MR imaging before microsurgical removal of extruded lumbar disk herniation material. Marrow signal intensity changes along the cartilaginous endplates were classified according to Modic types 1-3. Severity of changes was evaluated with respect to extension along the endplate in the anteroposterior diameter (0%, <33%, 33%-66%, >66%). The existence of a dorsal vertebral corner defect was evaluated in relation to the existence of hyaline cartilage in the disk extrusion material. RESULTS: Mean tissue composition of herniated material in all patients was 63% anulus fibrosus, 30% nucleus pulposus, and 8% cartilaginous endplate. Twenty-five of the 51 patients had hyaline cartilaginous material in the extrusion (range, 5%-50%). Patients without marrow signal intensity changes along the cartilaginous endplate showed significantly less cartilaginous material in the extruded disk (P =.023, Fisher exact test). Mean percentage hyaline cartilage in patients without changes was 2% +/- 4 (SD) (Modic type 1, 16% +/- 15; type 2, 10% +/- 12). When the changes extended 33% of the vertebral endplate, there was cartilaginous endplate material in the extruded disk (P =.006). Cartilage from the endplate was present in the extruded disk material in 40% (16 of 40) of patients without a vertebral corner defect and in 82% (nine of 11) of patients with a vertebral corner defect (P =.019). CONCLUSION: Avulsion-type disk herniation seems to be common, and vertebral endplate marrow signal intensity changes on MR images are indicative of cartilaginous material in the extruded disk herniation material.     

Bone marrow edema pattern in advanced hip osteoarthritis: quantitative assessment with magnetic resonance imaging and correlation with clinical examination, radiographic findings, and histopathology

Objective To correlate the amount of bone marrow edema (BME) calculated by magnetic resonance imaging(MRI) with clinical findings, histopathology, and radiographic findings, in patients with advanced hip osteoarthritis(OA). Materials and methods The study was approved by The Institutional Human Subject Protection Committee. Coronal MRI of hips was acquired in 19 patients who underwent hip replacement. A spin echo (SE) sequence with four echoes and separate fast spin echo (FSE) proton density (PD)-weighted SE sequences of fat (F) and water (W) were acquired with water and fat suppression, respectively. T2 and water:fat ratio calculations were made for the outlined regions of interest. The calculated MRI values were correlated with the clinical, radiographic, and histopathologic findings. Results Analyses of variance were done on the MRI data for W/(W + F) and for T2 values (total and focal values) for the symptomatic and contralateral hips. The values were significantly higher in the study group. Statistically significant correlations were found between pain and total W/(W + F), pain and focal T2 values, and the number of microfractures and calculated BME for the focal W/(W + F) in the proximal femora. Statistically significant correlations were found between the radiographic findings and MRI values for total W/(W + F), focal W/(W + F) and focal T2 and among the radiographic findings, pain, and hip movement. On histopathology, only a small amount of BME was seen in eight proximal femora. Conclusion The amount of BME in the OA hip, as measured by MRI, correlates with the severity of pain, radiographic findings, and number of microfractures.     

Phyllodes tumor of the breast: correlation between MR findings and histologic grade

PURPOSE: To retrospectively evaluate the magnetic resonance (MR) imaging findings of phyllodes tumor of the breast and to compare these findings with the histologic grade. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. The authors reviewed the MR findings in 30 female patients aged 16-73 years (mean, 40.2 years) with surgically confirmed phyllodes tumors. Analyzed MR findings included tumor shape, margin, internal enhancement, and size; signal intensity (SI) of tumor higher than that of normal breast tissue on T1-weighted images; SI of tumor lower than or equal to that of normal tissue on T2-weighted images; cyst wall appearance; kinetic curve assessment; and apparent diffusion coefficient (ADC). The MR findings and histologic grade were statistically analyzed to determine whether any correlations existed. Significant MR findings were compared with histopathologic findings. RESULTS: Nineteen benign, six intermediate (characterized by five to nine cell reproductions at 10 high-power fields, pushing or infiltrative margins, moderate stromal cellularity, and atypia and overgrowth), and five malignant phyllodes tumors were assessed. Irregular cyst wall (P = .003), tumor SI lower than or equal to normal tissue SI on T2-weighted images (P = .005), and low ADC (P = .001) correlated significantly with histologic grade. Tumor SI higher than normal tissue SI on T1-weighted images was more frequent in the malignant (in three of five tumors) and intermediate (in three of six tumors) groups than in the benign group (in two of 19 tumors); however, it was not a significant finding (P = .024). Tumor SI higher than normal tissue SI on T1-weighted images and irregular cyst wall corresponded histopathologically to hemorrhagic infarction and necrosis, respectively. Tumor SI lower than or equal to normal tissue SI on T2-weighted images and low ADC corresponded histopathologically to stromal hypercellularity. Other findings were not significant. CONCLUSION: Several MR findings can be used to help determine the histologic grade of phyllodes breast tumors.     

Transient bone marrow edema of the talus: MR imaging findings in five patients

OBJECTIVE: To describe the MR findings of transient bone marrow edema (TBME) of the talus and to address the differential diagnostic considerations. DESIGN AND PATIENTS: The imaging findings of TBME of six tali were retrospectively reviewed in five patients with a clinical history of pain without trauma. Inclusion criteria were MR imaging findings that, when compared with clinical data and results of follow-up assessment, allowed the diagnosis of TBME. MR imaging, standard radiography, and bone scintigraphy were performed. The images were reviewed with particular attention to the pattern and distribution of abnormal marrow signal intensity as well as associated findings. RESULTS: In four cases the entire talus was involved, and in two cases only a portion of the bone was affected. No fractures were detected. MR imaging demonstrated diffuse decreased signal intensity of the marrow on T1-weighted images with corresponding increased signal intensity on T2-weighted images. In all six cases MR imaging detected associated findings, which included joint effusion and soft tissue edema. All patients improved clinically with conservative therapy over a period of 6 months to 1 year. CONCLUSIONS: Although unusual, TBME can involve the talus. Marrow edema without evidence of a fracture and in the absence of history of trauma is a characteristic MR imaging feature, allowing confident diagnosis and institution of conservative therapy.     

Normal and degenerating articular cartilage: in vitro correlation of MR imaging and histologic findings.

Histologic correlation of the different magnetic resonance (MR) appearances of articular cartilage has not been studied extensively. Therefore, the authors correlated thin (high-resolution) MR sections of articular cartilage with histologic sections. Human cadaver lumbar facet joints were imaged with a 1-mm section thickness and a 4-cm field of view, then sectioned and stained for histologic comparison. MR imaging patterns were identified that correlated with normal cartilage and three histologically different patterns of degeneration.     

Peripheral (extracranial) nerve tumors: correlation of MR imaging and histologic findings.

Magnetic resonance (MR) images of 16 peripheral nerve tumors (14 patients) were correlated with histopathologic appearance. Thirteen patients had surgically proved neuro-fibromatosis. There were 10 neurofibromas, four schwannomas, and two neurofibrosarcomas. Seven of the 10 neurofibromas showed a target pattern of increased peripheral signal intensity and decreased central signal intensity on T2-weighted images. This pattern appeared to correspond to a distinctive zonal histologic appearance that was found only in the neurofibromas. This pattern was not seen on MR images of the other peripheral tumors.     

Diffusion-weighted MR imaging of intracerebral masses: comparison with conventional MR imaging and histologic findings

BACKGROUND AND PURPOSE: The purposes of this study were to find the role of diffusion-weighted MR imaging in characterizing intracerebral masses and to find a correlation, if any, between the different parameters of diffusion-weighted imaging and histologic analysis of tumors. The usefulness of diffusion-weighted imaging and apparent diffusion coefficient (ADC) maps in tumor delineation was evaluated. Contrast with white matter and ADC values for tumor components with available histology were also evaluated. METHODS: Twenty patients with clinical and routine MR imaging/CT evidence of intracerebral neoplasm were examined with routine MR imaging and echo-planar diffusion-weighted imaging. The routine MR imaging included at least the axial T2-weighted fast spin-echo and axial T1-weighted spin-echo sequences before and after contrast enhancement. The diffusion-weighted imaging included an echo-planar spin-echo sequence with three b values (0, 300, and 1200 s/mm(2)), sensitizing gradient in the z direction, and calculated ADC maps. The visual comparison of routine MR images with diffusion-weighted images for tumor delineation was performed as was the statistical analysis of quantitative diffusion-weighted imaging parameters with histologic evaluation. RESULTS: For tumors, the diffusion-weighted images and ADC maps of gliomas were less useful than the T2-weighted spin-echo and contrast-enhanced T1-weighted spin-echo images in definition of tumor boundaries. Additionally, in six cases of gliomas, neither T2-weighted spin-echo nor diffusion-weighted images were able to show a boundary between tumor and edema, which was present on contrast-enhanced T1-weighted and/or perfusion echo-planar images. The ADC values of solid gliomas, metastases, and meningioma were in the same range. In two cases of lymphomas, there was a good contrast with white matter, with strongly reduced ADC values. For infection, the highest contrast on diffusion-weighted images and lowest ADC values were observed in association with inflammatory granuloma and abscess. CONCLUSION: Contrary to the findings of previous studies, we found no clear advantage of diffusion-weighted echo-planar imaging in the evaluation of tumor extension. The contrast between gliomas, metastases, meningioma, and white matter was generally lower on diffusion-weighted images and ADC maps compared with conventional MR imaging. Unlike gliomas, the two cases of lymphomas showed hyperintense signal on diffusion-weighted images whereas the case of cerebral abscess showed the highest contrast on diffusion-weighted images with very low ADC values. Further study is required to find out whether this may be useful in the differentiation of gliomas and metastasis from lymphoma and abscess.     

Dynamic MR imaging of breast lesions: correlation with microvessel distribution pattern and histologic characteristics of prognosis

PURPOSE: To evaluate the association of dynamic enhancement parameters of benign and malignant breast lesions at magnetic resonance (MR) imaging with microvessel distribution and histologic prognostic tumor characteristics. MATERIALS AND METHODS: Regional review board approval and informed consent were obtained. Surgical resection specimens of breast lesions (32 benign, 86 malignant) in 118 patients (age range, 28-86 years; mean, 58 years) who had undergone dynamic T1-weighted MR imaging of both breasts were included in the study. Different MR enhancement parameters and microvessel density (MVD) distribution were determined. In malignant lesions, TNM stage, tumor grade, proliferative activity, and hormone receptor expression were determined. Spearman correlation coefficients; Wilcoxon, Fisher exact, Kruskal Wallis, and chi(2) tests; and logistic regression analysis were used for evaluation. RESULTS: Malignant lesions exhibited a higher ratio of microvessels in tumor periphery versus tumor center than did benign lesions (P < .0005). High vessel ratios (P = .001) and low central vessel numbers (P = .007) were associated with high tumor grade. In malignant lesions, initial enhancement ratios of periphery to center of lesion correlated with the corresponding microvessel ratios (r = 0.61). Yet, a high peripheral MVD was not associated with strong peripheral enhancement (r = -0.09). High enhancement ratios, washout rates, and early enhancement peaks were associated with unfavorable, albeit not significant, prognostic indicators. Visible rim enhancement was the most accurate prognostic enhancement criterion for estrogen receptor status (P = .007), tumor grade (P = .06), and lymph node status (P = .046). Washout was the best discriminating criterion for proliferative activity. CONCLUSION: The different enhancement behaviors of malignant and benign breast lesions cannot be explained by MVD alone; however, a low MVD in the center of carcinoma is reflected quantitatively by a high enhancement ratio and qualitatively by rim enhancement, with an implication of adverse prognosis.     

Cavernous sinus: correlation between anatomic and dynamic gadolinium- enhanced MR imaging findings

Dynamic magnetic resonance (MR) images were evaluated and compared with conventional T1-weighted spin-echo (SE) images obtained before and after administration of gadopentetate dimeglumine in 20 patients with normal cavernous sinuses. Starting 10 seconds after rapid injection of gadopentetate dimeglumine (0.1 mmol/kg), six to eight serial images were obtained every 30 seconds for 3-5 minutes. The venous spaces of the cavernous sinus were markedly enhanced 30 seconds after injection. Cranial nerves III and IV, V1 and VI, and V2 were seen on 75% of dynamic images each; they were seen, respectively, on 62%, 30%, and 28% of conventional postcontrast images. The medial wall was demarcated on 90% of dynamic, 15% of precontrast, and 55% of postcontrast images. A small area of connective tissue was identified within the cavernous sinus on dynamic images showing gradual enhancement. It is concluded that dynamic MR images proved useful in delineating and distinguishing abnormal tissue from normal structures.     

Bone marrow disorders: characterization with quantitative MR imaging

Thirty patients with various hematologic disorders and 15 healthy control subjects underwent quantitative magnetic resonance (MR) imaging of the lumbar spine with spin-echo techniques. Images of patients with infiltrative bone marrow disorders showed significantly more prolonged T1 times than those of control subjects (P less than .001). It was not possible to distinguish different diffuse infiltrative bone marrow disorders on the basis of T1 values. Aplastic anemia could be distinguished from normality because of significantly shortened T1 (P less than .001). A significant correlation was seen between T1 and bone marrow cellularity (r = .74, P less than .001). T2 was of no value in the characterization of bone marrow disorders. Quantitative MR imaging dose not improve the diagnostic potential of bone marrow imaging in the detection of diffuse marrow infiltrates.     

Subchondral marrow changes after laser diskectomy in the lumbar spine: MR imaging findings and clinical correlation

OBJECTIVE: We examined MR imaging findings and determined the clinical significance of subchondral bone marrow changes in the lumbar spine of holdium:yttrium aluminum garnet laser diskectomy patients. MATERIALS AND METHODS: We retrospectively reviewed the pre- and postoperative MR images of 109 patients with recurrent radiculopathy, lower back pain, or both 1 year after laser diskectomy of 178 disks. From this group of patients, MR images were also obtained in 11 patients with subchondral marrow changes 5-7 years after surgery. These patients were interviewed regarding residual lower back pain. Thirteen asymptomatic laser diskectomy patients also underwent follow-up MR imaging within 1 year of surgery. RESULTS: After surgery, subchondral marrow abnormalities were identified in 41 of 109 laser diskectomy patients. The remaining 68 patients had no postoperative subchondral bone marrow changes. Postoperative subchondral marrow changes were not associated with inflammation of the adjacent disk space and did not affect surgical outcome. Bone marrow changes decreased in size in the 11 patients examined 5-7 years after laser diskectomy, and eight of these patients described their lower back pain as improved. In 13 asymptomatic laser diskectomy patients, one new subchondral marrow abnormality was identified. CONCLUSION: Subchondral marrow abnormalities may occur in the vertebral end plates after holmium:yttrium aluminum garnet laser diskectomy. However, these changes probably do not affect surgical outcomes and appear to resolve over time.