Initial experience with dynamic MR imaging in evaluation of normal bone marrow versus malignant bone marrow infiltrations in humans

The purpose of this study was (a) evaluation of dynamic contrast-enhanced MR imaging of normal bone marrow versus malignant bone marrow infiltrations in patients with proven B-cell-type chronic lymphocytic leukemia (B-CLL) and (b) correlation with the clinical stage according to Binet (stages A, B, C) and response to therapy. Bone marrow imaging of the lumbar spine, pelvis, and proximal femurs was performed at 1.5 T in 45 patients without known malignancy and in 30 patients with B-CLL. The differences between opposed-phase and in-phase dynamic gradient-echo sequences before and up to 10 minutes after intravenous application of .1 mmol/kg body weight of gadolinium-diethylenetriamine penta-acetic acid (Gd-DTPA) were evaluated in normal bone marrow. The contrast-enhancement patterns of normal and malignant bone marrow were compared using the opposed-phase dynamic gradient-echo sequence. Ten of the patients with bone marrow infiltrations (Binet stage C) additionally underwent MR imaging follow-up during therapy. Opposed-phase gradient echo sequences demonstrated a signal decrease of normal bone marrow, and in-phase gradient echo sequences demonstrated a signal increase of normal bone marrow after administration of Gd-DTPA. The dynamic signal intensity time courses differed significantly (P < .05) between Binet stages B and C and controls as well as among the three Binet stages of B-CLL. In the 10 patients followed during therapy, MR imaging sensitively demonstrated response (n = 6), nonresponse (n = 2), or relapse after initial response (n = 2). In out-of-phase imaging, both normal bone marrow and initial bone marrow infiltration in CLL stage Binet A show signal decrease after administration of contrast agent, whereas there is increase in signal intensity in higher-grade bone marrow infiltration in Binet stage B or C disease. The signal loss of normal bone marrow in out-of-phase imaging is a phase effect rather than a T2* effect. The differentiation of initial from higher-grade bone marrow infiltration on out-of-phase images relies solely on a shift in the fat/water ratio.     

Bone bruises: MR characteristics and histological correlation in the young pig

PURPOSE: To correlate magnetic resonance (MR) signal characteristics of bone bruises with histological findings. MATERIALS AND METHODS: In 14 tibiae of young pigs, bone bruises were created in the proximal tibial metaphysis. The signal intensity seen on the MR images were correlated with histological findings. The following findings were evaluated: (a) changes of signal intensity on the tibiae; (b) changes of histology on the tibiae; and (c) changes of (a) and (b) on follow-up examinations. RESULTS: We observed three types of injuries on T1-weighted images: focal or diffuse low signal, normal signal and linear low signal intensities. Severe hemorrhagic areas showed low signal intensities on all sequences of MR imaging. Fast spin-echo (FSE) T2-weighted images showed a more distinct low signal intensity than T1-weighted images. FSE short tau inversion recovery (STIR) and FSE fat saturated (FSE-FS) T2-weighted images showed similar signal intensities with FSE T2-weighted images. FS T1-weighted enhanced images showed low signal intensities with variable enhancements. Upon histological examination, hemorrhages and edemas were prominent at the subcortical areas of the contusion sites. The areas of dense, low signal intensities in all imaging sequences showed signs of severe hemorrhage. The areas of diffuse low signal and enhanced areas showed mixed areas of hemorrhages and edemas. Follow-up MR imaging showed evolution of the processes of hemorrhages and edemas with fatty marrow changes. CONCLUSIONS: MR imaging can depict changes in the bone marrow resulting from direct injury to the bone. MR imaging is a useful tool for evaluating the evolution of bone bruises.     

Iron-oxide-enhanced MR imaging of bone marrow in patients with non-Hodgkin's lymphoma: differentiation between tumor infiltration and hypercellular bone marrow

The aim of this study was to differentiate normal, hypercellular, and neoplastic bone marrow based on its MR enhancement after intravenous administration of superparamagnetic iron oxides in patients with cancer of the hematopoietic system. Eighteen patients with cancer of the hematopoietic system underwent MRI of the spine before and after infusion of ferumoxides ( n=9) and ferumoxtran ( n=9) using T1- and T2-weighted turbo spin-echo (TSE) and short tau inversion recovery sequences (STIR). In all patients diffuse or multifocal bone marrow infiltration was suspected, based on iliac crest biopsy and imaging such as conventional radiographs, MRI, and positron emission tomography. In addition, all patients had a therapy-induced normocellular ( n=7) or hypercellular ( n=11) reconversion of the normal non-neoplastic bone marrow. The MRI data were analyzed by measuring pre- and post-contrast signal intensities (SI) of hematopoietic and neoplastic marrow and by calculating the enhancement as deltaSI(%) data and the tumor-to-bone-marrow contrast as contrast-to-noise ratios (CNR). Changes in bone marrow signal intensity after iron oxide administration were more pronounced on STIR images as compared with T1- and T2-weighted TSE images. The STIR images showed a strong signal decline of normal and hypercellular marrow 45-60 min after iron oxide infusion, but no or only a minor signal decline of neoplastic bone marrow lesions; thus, deltaSI% data were significantly higher in normal and hypercellular reconverted marrow compared with neoplastic bone marrow lesions ( p<0.05). Additionally, the contrast between focal or multifocal neoplastic bone marrow infiltration and normal bone marrow, quantified by CNR data, increased significantly on post-contrast STIR images compared with precontrast images ( p<0.05). Superparamagnetic iron oxides are taken up by normal and hypercellular reconverted bone marrow, but not by neoplastic bone marrow lesions, thereby providing significantly different enhancement patterns on T2-weighted MR images; thus, superparamagnetic iron oxides are useful to differentiate normal and neoplastic bone marrow and to increase the bone marrow-to-tumor contrast.     

Magnetic resonance imaging of bone marrow changes in Gaucher disease during enzyme replacement therapy: first German long-term results

Objective: . Since 1991, enzyme replacement therapy (ERT) has been available for patients with Gaucher disease in Germany. The aim of this study was to analyse the MR pattern of bone marrow involvement and response to ERT in Gaucher disease type I. Patients and design: . Thirty patients with Gaucher disease type I had MRI examinations prior to initiation of ERT with alglucerase/imiglucerase and during follow-up. Median MR follow-up and duration of ERT were 36 months. Coronal T1- and T2-weighted spin-echo images of the lower extremities were obtained to evaluate changes in the appearance of yellow marrow. MR images were categorized as having either a homogeneous (type A) or non-homogeneous patchy (type B) appearance of bone involvement and response to ERT was assessed by two radiologists. Results: . Overall, 19 of 30 patients (63%) showed an increased signal intensity on T1- and T2-weighted images after 36 months of ERT, consistent with partial reconversion of fatty marrow during treatment. Focal bone lesions surrounded by a low signal intensity (SI) rim did not respond to ERT, suggesting bone infarcts. Of the 11 patients with bone infarcts (low SI rim lesion), 82% had the non-homogeneous type B pattern (P=0.0021). In 86% of patients with splenectomy, bone infarcts were seen (P<0.05). Conclusions: . MRI using T1- and T2-weighted spin-echo sequences is a valuable, non-invasive method for monitoring bone marrow response in patients receiving ERT. A non- homogeneous patchy signal intensity of bone marrow involvement correlates with the presence of bone infarcts (P=0.0021). Received: 27 July 2000 Revision requested: 26 October 2000 Revision received: 9 March 2001 Accepted: 12 March 2001     

Bone marrow characterization in the lumbar spine with inner volume spectroscopic CPMG imaging studies

The authors describe new magnetic resonance (MR) spectroscopic and postprocessing methods for characterizing major proton peaks and their spectral T2 values in many small voxels throughout extensive regions of bone marrow within the adult lumbar spine. The techniques are based on spectroscopic interrogation of 128 voxels along columns oriented through the spine at eight TE values. Mean fat content measurements, based on quantification of the proton peaks of water and saturated fat (-CH₂-)_n, corrected for T2 decay, ranged from 40% to 60%. The mean T2 value of the lipid peak, 113 msec ±21, was significantly longer (P <.001) than that of water (71 msec ± 14). The techniques combine features of MR spectroscopy and imaging most suited for spatially efficient coverage of bone marrow at spectral resolutions sufficient for intravoxel fat or water content measurements. The methods introduced provide a practical, quantitative means for characterizing vertebral marrow in diseases affecting marrow cellularity.     

Ultrasmall superparamagnetic iron-oxide-enhanced MR imaging of normal bone marrow in rodents: original research original research

RATIONALE AND OBJECTIVES: The objective is to compare three different ultrasmall superparamagnetic iron oxides (USPIOs) for magnetic resonance (MR) imaging of normal bone marrow in rodents. MATERIALS AND METHODS: Femoral bone marrow in 18 Sprague-Dawley rats was examined by using MR imaging before and up to 2 and 24 hours postinjection (PI) of 200 mumol of Fe/kg of SHU555C (n = 6), ferumoxtran-10 (n = 6), or ferumoxytol (n = 6), using T1-weighted (50 ms/1.7 ms/60 degrees = repetition time [TR]/echo time [TE]/flip angle) and T2*-weighted (100 ms/15 ms/38 degrees = TR/TE/flip angle) three-dimensional spoiled gradient recalled echo sequences. USPIO-induced bone marrow was evaluated qualitatively and quantified as signal-to-noise ratio (SNR) and change in signal intensity (DeltaSI) values. A mixed-effect model was fitted to the SNR and DeltaSI values, and differences among USPIOs were tested for significance by using F tests. RESULTS: At 2 hours PI, all three USPIOs showed marked positive signal enhancement on T1-weighted images and a corresponding marked signal loss on T2*-weighted images. At 24 hours PI, the T1 effect of all three USPIOs disappeared, whereas T2*-weighted images showed persistent signal loss on SHU555C and ferumoxytol-enhanced MR images, but not ferumoxtran-10-enhanced MR images. Corresponding SNR and DeltaSI values on T2*-weighted MR images at 24 hours PI were significantly different from baseline for SHU555C and ferumoxytol, but not ferumoxtran-10. CONCLUSION: All three USPIO contrast agents, ferumoxtran-10, ferumoxytol, and SHU555C, can be applied for MR imaging of bone marrow. Ferumoxtran-10 apparently reveals a different kinetic behavior in bone marrow than ferumoxytol and SHU555C.     

Chronic lymphocytic leukemia: Changes in bone marrow composition and distribution assessed with quantitative MRI

The purposes of this study were (α) to determine the prevalence of bone marrow abnormalities in patients with chronic lymphocytic leukemia (CLL) using quantitative MR assessment of axial marrow composition and peripheral marrow distribution; (b) to assess the agreement between both quantitative MR methods and compare their sensitivities to detect marrow alterations; and (c) to correlate MR findings with clinical and laboratory parameters. Twenty-nine consecutive patients with biopsy-proven CLL were investigated on a .5-T MR imager to determine bulk T1 relaxation times of the vertebral bone marrow and proportion of proximal femur surface area occupied by nonfatty marrow on coronal T1-weighted MR images of one hip. Of the 29 patients, 12 (41%) had abnormal increase in lumbar marrow T1 values (>600 msec) and 16 (55%) had increased proportion of surface area occupied by non-fatty marrow in the proximal femur (>+1 SD compared to normal values determined in sex- and age-matched healthy subjects). The results of both quantitative MR methods were normal in 12 patients and abnormal in 11 patients (agreement, 79%). Patients with alterations in peripheral marrow distribution had significantly higher T1 relaxation times (P = .001) than those with normal peripheral marrow. Patients with abnormal marrow composition or distribution at MRI had significantly higher blood and marrow lymphocytosis than patients without these features. In conclusion, the agreement between both quantitative MR methods suggests a parallelism between changes in axial marrow composition and in peripheral marrow distribution in patients with CLL. The limits of quantitative MRI in CLL must be kept in mind, because quantitative MR methods failed to detect leukemic marrow infiltration in 41% of patients.     

MR imaging of avascular scaphoid nonunion before and after vascularized bone grafting

Objective To investigate the magnetic resonance (MR) imaging appearances of chronic nonunion of the scaphoid with proximal pole avascular necrosis before and after insertion of a vascularized bone graft, using computed tomography (CT) as the imaging gold standard.Design and patients A retrospective study was performed involving MR imaging (n=26), CT scans (n=37) and radiographs (n=52) of 13 men (mean age 29 years, age range 20–38 years) with avascular scaphoid nonunion. Avascular necrosis of the scaphoid proximal pole was confirmed intraoperatively (n=13). MR images were acquired preoperatively and following placement of a vascularized bone graft. Scaphoid MR signal characteristics were assessed for evidence of vascular bone graft incorporation and revascularization of the bone marrow of the proximal pole of the scaphoid and compared with the gold standard of CT. Surgical and clinical notes were reviewed with a minimum 3 year imaging and clinical follow-up in all patients.Results Graft incorporation with revascularization of the proximal pole of the scaphoid was documented in 9 patients (69%). Graft failure with persistent pseudoarthrosis and avascular necrosis of the scaphoid was seen in 4 patients (31%).Conclusions MR imaging is useful to determine whether vascularized bone graft incorporation and revascularization of the proximal pole of the scaphoid has occurred in the setting of avascular scaphoid nonunion.Paper presented at ESSR, European Society of Skeletal Radiology, Aarhus, Denmark, 14 June 2003. Awarded first prize for the ESSR award for Scientific PresentationsPaper presented at ISS, Closed Scientific Session, Malta, 3 October 2004 as part of the above prize     

MR imaging of edema accompanying benign and malignant bone tumors

To evaluate the incidence, quantity, and presentation of intra- and extraosseous edema accompanying benign and malignant primary bone lesions, the magnetic resonance (MR) studies of 63 consecutive patients with histologically proven primary bone tumors were reviewed. MR scans were assessed for the presence and quantity of marrow and soft tissue edema and correlated with peroperative findings, resected specimens and follow-up data. The signal intensity and enhancement of tumor and edema prior to and after intravenous administration (if any) of gadolinium-labled diethylene triamine pentaacetate (Gd-DTPA) was analyzed. Marrow edema was encountered adjacent to 8 of 39 malignant tumors and 14 of 24 benign lesions. Soft tissue edema was found accompanying 28 of 39 malignancies and 10 of 24 benign disorders. On unenhanced T1-weighted MR images tumor and edema were difficult to differentiate. Tumor inhomogeneity made this differentiation easier on T2-weighted sequences. In 36 patients the contrast medium Gd-DTPA was used. Edema was present in 27 of these patients and the respective enhancement of tumor and edema could be compared. Edema always enhanced homogeneously, and in most cases it enhanced to a similar degree as or more than tumor. Marrow and, more specifically, soft tissue edema is a frequent finding adjacent to primary bone tumors. The mere presence and quantity of marrow and soft tissue edema are unreliable indicators of the biologic potential of a lesion. Unenhanced MR scans cannot always differentiate between tumor and edema, but the administration of Gd-DTPA is of assistance in differentiating tumor from edema. Awareness of marrow and/or soft tissue edema adjacent to bone lesions is of importance because edema can be a pitfall in the diagnostic work-up and staging prior to biopsy or surgery.     

MR imaging of skeletal metastases from medulloblastoma

The findings of MR imaging in 3 patients with bone metastases from medulloblastoma are reported. The first patient showed focal lesions of low signal intensity on T1-weighted spin echo images at a time when bone scintigraphy was negative for metastases. This patient later developed extensive osteosclerotic lesions visible on plain films. The bone marrow of the second patient showed diffuse low signal intensity on T1-weighted images. After chemotherapy the signal intensity of the bone marrow increased which correlated with a return of normal hematopoietic tissue. A response to chemotherapy was also found on MR imaging and repeat bone marrow biopsies in a third patient. A consistent finding was a low signal intensity on pre-gadolinium images, but the pattern (focal or diffuse abnormal signal intensity) was different in each patient. To our knowledge, this is the first report on MR imaging findings in bone metastases from medulloblastoma.     

Hematopoietic bone marrow in the adult knee: spin-echo and opposed-phase gradient-echo MR imaging

Hematopoietic bone marrow in the distal femur of the adult may be mistaken for a pathologic marrow process in magnetic resonance imaging of the knee. We investigated the incidence of hematopoietic marrow in the distal femur in a series of 51 adult patients and compared spin-echo (TR/TE in ms: 500/35, 2000/80) and opposed-phase gradient-echo (0.35 T, TR/TE in ms: 1000/30, = 75°) magnetic resonance images. Zones with intermediate to low signal intensity on T1-weighted spinecho and opposed-phase gradient-echo sequences representing hematopoietic marrow within high signal intensity fatty marrow were observed in 18 of the 51 patients. Five patterns of marrow signal reduction were identified; type 0: uniform high signal, i.e., no signal change; type I, focal signal loss; type II, multifocal signal loss without confluence; type III, confluent signal loss; and type IV, complete homogeneous reduction in marrow signal. Opposed-phase gradient-echo sequences demonstrated markedly greater red-yellow marrow contrast than conventional spin-echo sequences. Follow-up studies in three patients using a gradient-echo sequence with TE varying from 10 to 21 ms at 1-ms increments showed a cyclic increase and decrease in red and yellow marrow signal intensity depending on the TE. The contribution of intravoxel chemical shift effects on red-yellow marrow contrast in opposed-phase gradient-echo images was verified by almost complete cancellation of the TE-dependent marrow signal oscillation with use of a chemically selective pulse presaturating the water protons.Hematopoietic marrow in the adult distal femur in the absence of hematologic abnormalities is found primarily in women of menstruating age. It may be residual and may represent a biologic variation in the normal adult pattern of red-yellow marrow distribution. Reconverted red marrow appears to be related to increased erythrocyte demand. Residual and reconverted red marrow should not be mistaken for bone marrow malignancy. Opposed-phase gradient-echo imaging is easily implemented and appears ideally suited to monitor the distribution of hematopoietic marrow as a function of age and erythrocyte demand in vivo.     

常见血液病的骨髓磁共振成像

磁共振成像(MRI)以其无创伤性、直接显示骨髓、检测异常骨髓的能力而成为评价骨髓病变的首选影像学检查方法。随着年龄的增长，正常人红骨髓按照一定规律转换为黄骨髓，MRI表现也发生相应的变化。多种原发血液病可引起骨髓MRI信号异常，甚至骨髓T1的变化。白血病骨髓典型表现为弥漫性的T1WI低信号，T1延长；白血病治疗后缓解，T1缩短接近正常范围。淋巴瘤及多发性骨髓瘤的MRI表现多种多样，取决于病变的恶性程度，但骨髓的T1均延长。再生障碍性贫血具有特征性的T1WI、T2WI高信号。增生性贫血由于红骨髓增生，黄骨髓逆转为红骨髓，贫血严重时甚至骨骺内的黄骨髓逆转为红骨髓。     

Fatty replacement of bone marrow after radiation therapy for Hodgkin disease: Quantification with chemical shift imaging

The authors studied the long-term fatty replacement of bone marrow in 23 patients who had received radiation therapy for Hodgkin disease, with T1-weighted magnetic resonance imaging and quantitative chemical shift imaging. T1-weighted images revealed a mostly homogeneous high-signal-intensity pattern, in contrast to the hypointense pattern of nonirradiated marrow. The degree of fatty replacement was objectively assessed with chemical shift imaging, comparing patients to age-matched healthy volunteers. The authors found an increase in relative fat signal of 37% in the thoracic spine and 34% in the lumbar spine. The relative fat signal of nonirradiated pelvic and femoral marrow was decreased by 8%, indicating marrow reconversion. No radiation dose dependence was found in the range from 25 to 50 Gy. No signs of marrow regeneration were observed 15-126 months after radiation therapy. With chemical shift imaging, the degree of long-term radiogenic fatty replacement of the bone marrow can be quantified, confirming the lack of regeneration after radiation therapy for Hodgkin disease.     

MR imaging of the foot and ankle: patterns of bone marrow signal abnormalities

Diagnosis of marrow disorders of the foot and ankle is among the more challenging aspects of MR interpretation. Evaluation of normal and abnormal bone marrow with regard to pattern, distribution, and signal characteristics on different sequences often allows a specific diagnosis. This pictorial review illustrates MR imaging findings of normal variants of bone marrow of the foot and ankle, and the varied responses of bone marrow to trauma, stress, or disease.     

MR imaging findings in transient osteoporosis of the hip

Purpose: The authors sought to describe the magnetic resonance (MR) imaging findings including perfusion imaging, in association with the course of acute bone marrow oedema syndrome (aBMEs), in a group of patients with acute hip pain and a final diagnosis of transient osteoporosis of the hip (TOH). Materials and methods: From 217 patients referred with a probable diagnosis of avascular necrosis (AVN) of the femoral head, we identified 42 patients who had clinical and radiographic findings not relevant to AVN. MR imaging examinations were performed on a 1.0T scanner. Perfusion imaging was performed in 20 patients. The bone marrow oedema (BME) was classified in four stages. In addition, the presence or absence of oedema in the subchondral area and the presence of other subchondral lesions were recorded. Acetabular bone marrow was also assessed for the presence of oedema. The quantitative measurements included: maximum size of the effusion, percentage of enhancement (PE) and time of peak enhancement of abnormal marrow compared to the first pass, on the perfusion images. Results: Osteopenia was present on plain radiographs in 87% of cases. The most common pattern of BME was extending to the femoral head and neck. Acetabulum was involved in 16.6%. In 22.6% the BME spared the subchondral region of the femoral head. There were two cases (4.7%) with subchondral changes. A joint effusion was noted in 33 of the 42 patients. On perfusion imaging, a delayed peak enhancement was noted in 20 patients between 40 and 65 s after the first pass of contrast. No patient had any evidence of femoral head collapse or change in sphericity on follow-up MRI. None of the patients developed avascular necrosis in a time frame of 18 months from the onset of the acute hip pain. Conclusion: The aBMEs MR imaging pattern varies and is most commonly appearing on X-rays as osteopenia. Absence of subcondral lesions, delayed peak enhancement of the abnormal marrow on perfusion images, and sparing of subchondral zone from marrow oedema are MR imaging findings highly correlated to TOH.     

Imaging characteristics of toxoplasmosis encephalitis after bone marrow transplantation: report of two cases and review of the literature

Toxoplasmosis encephalitis is a severe, but often misdiagnosed complication in patients after bone marrow transplantation (BMT). We describe the unique computed tomography (CT) and magnetic resonance (MR) imaging features of cerebral toxoplasmosis in two bone marrow recipients and compare them to the cases in the literature. To our knowledge, this is the first report analyzing the appearance of cerebral toxoplasmosis on diffusion-weighted MR imaging (DWI).     

The effect of human leukocyte antigen disparity on cyclosporine neurotoxicity after allogeneic bone marrow transplantation.

PURPOSEWe examined the relationship between human leukocyte antigen (HLA) matching and the development of cyclosporine (CyA) neurotoxicity in patients undergoing allogeneic bone marrow transplantation, and determined the frequency and imaging characteristics of CyA neurotoxicity in these patients.METHODSRecords of 87 patients who underwent allogeneic bone marrow transplantation were reviewed. Eight patients who presented with visual disturbance and/or seizures and had MR imaging within 24 hours were identified. Transplant donor relatedness was examined, and patients'' imaging studies were reviewed. Clinical parameters, including blood pressure, CyA, creatinine, and magnesium levels, and the presence of graft-versus-host disease were reviewed.RESULTSCyA neurotoxicity was seen more frequently in HLA-mismatched and unrelated donor transplants. The frequency of CyA neurotoxicity was 4% for patients with a 5/6 or 6/6 HLA match, 13% for matched unrelated donor transplants, and 50% for haplotypic 3/6 or 4/6 transplants. Patients with matched unrelated donor transplants and haplotypic transplants presented earlier in the posttransplant time course and had decreased survival time relative to patients with HLA-matched transplants. Imaging abnormalities most commonly affected the occipital lobes and the posterior cerebral hemispheres; both cortical and white matter involvement was identifiable as T1 hypointense and T2 hyperintense signal with associated gyral swelling and sulcal effacement on the initial MR studies. Hypodensity in the affected areas was noted on CT scans. Contrast enhancement was seen in HLA-mismatched and unrelated transplants only. Follow-up imaging showed interval decreases in subcortical edema; however, residual signal abnormality, primarily affecting the cortex, was present in all cases and seen best on proton density-weighted MR images.CONCLUSIONThe frequency of severe CyA neurotoxicity increases with increasing HLA disparity, suggesting that immune factors may play a role. CyA neurotoxicity appears to represent a spectrum of disease processes. Disruption of the blood-brain barrier as well as hypoxic or vasculitic cortical injury resulting in MR-detectable cortical signal abnormalities may occur in severe cases.     

Bone marrow MR imaging as predictors of outcome in hemopoietic stem cell transplantation

The purpose of this study is to investigate the role of femoral marrow MR imaging as predictor of outcome for hemopoietic stem cell transplantation (HSCT) in beta-thalassemia major. MR imaging of the proximal femur, including T1- and T2-weighted spin echo and short-tau inversion recovery and in-phase and out-of-phase fast field echo images, was prospectively performed in 27 thalassemia major patients being prepared for HSCT. The area of red marrow and its percentage of the proximal femur were measured, and the presence of marrow hemosiderosis was assessed. Age-adjusted multivariate logistic regression was used to determine the relationship between red marrow area percentage and marrow hemosiderosis and HSCT outcome. Red area percentage were less in patients with successful (90.25 +/- 4.14%) compared to unsuccessful transplants (94.54% +/- 2.93%; p = 0.01). Red marrow area percentage correlated positively with duration of symptoms(r = 0.428, p = 0.026) and serum ferritin (r = 0.511, p = 0.006). In multivariate-adjusted logistic regression analyses, red marrow area percentage was significantly inversely associated with successful HSCT (OR = 1.383, 95% CI: 1.059-1.805, p = 0.005). Marrow hemosidersosis and duration of sympotms and serum ferritin were not associated with HSCT outcome(p = 0.174, 0.974, 0.762, respectively). Red marrow area percentage of proximal femur on MR imaging is a useful predictor of HSCT outcome.     

Systemic mastocytosis: MRI of bone marrow involvement

Systemic mastocytosis (SM) is an abnormal proliferation of mast cells, located in different structures: skin, bone marrow, spleen, liver and lymph nodes. Magnetic resonance imaging was prospectively performed in ten patients diagnosed by bone marrow biopsy in order to describe the different patterns of bone marrow involvement. Coronal T1-weighted spin-echo images were obtained in vertebral, pelvic, humeral and femoral bones. Depending on the extension of the cell infiltration, three patterns of bone marrow involvement were used: normal/no involvement (N), non-homogeneous (NH) and homogeneous (H). All ten patients presented bone infiltration. The patterns observed were: spine (50 % NH, 50 % H), pelvis (70 % NH), humerus 100(NH) and femur 40 % (NH). T1-weighted MR imaging is a sensitive technique for detecting marrow abnormalities in patients with systemic mastocytosis. There is no correlation between percentage of mast cells in bone marrow biopsy and extent or pattern of bone marrow involvement. Received: 5 June 1998; Revision received: 23 November 1998; Accepted: 15 January 1999     

Diffusion-Weighted Imaging with Sensitivity Encoding (SENSE) for Detecting Cranial Bone Marrow Metastases: Comparison with T1-Weighted Images

Objective

This study was designed to determine whether diffusion-weighted imaging (DWI) with sensitivity encoding (SENSE) could detect bone marrow involvement in patients with cranial bone marrow (CBM) metastases. DWI results obtained were compared with T1-weighted imaging (T1WI) findings.

Materials and Methods

DWI with sensitivity encoding (SENSE; b value = 1,000) was performed consecutively in 13 patients with CBM metastases diagnosed pathologically and radiologically. CBM lesions were dichotomized according to the involved site, i.e., skull base or calvarium. Two radiologists qualitatively evaluated the relative conspicuousness of CBM lesions and image qualities in B0 and in isotropic DWI and in T1WI. According to region of interest analysis of normal and pathologic marrow for these three sequences, absolute signal difference percentages (SD%) were calculated to quantitatively analyze lesion contrast.

Results

All 20 lesions in 13 patients with CBM metastases revealed abnormal DWI signals in areas corresponding to T1WI abnormalities. Both skull base and calvarial lesions provided better lesion conspicuousness than T1WI and B0 images. Although the image quality of DWI was less satisfactory than that of T1WI, relatively good image qualities were obtained. Quantitatively, B0 images (SD%, 82.1 ±7.9%) showed better lesion contrast than isotropic DWI (SD%, 71.4 ±13.7%) and T1WI (SD%, 65.7 ±9.3%) images.

Conclusion

For scan times of less than 30 seconds, DWI with SENSE was able to detect bone marrow involvement, and was superior to T1WI in terms of lesion conspicuity. DWI with SENSE may be helpful for the detection of cranial bone/bone marrow metastases when used in conjunction with conventional MR sequences.