长骨骨干骨肉瘤X线、CT及MRI表现

目的 分析长骨骨干骨肉瘤X线、CT和MRI表现,探讨有关的临床特点和鉴别诊断.方法 28例长骨骨干骨肉瘤患者,均经手术与病理证实,其中病变位于股骨干18例、腓骨干4例、肱骨干4例、胫骨干2例.所有患者均行X线、CT和MR检查,对其影像学表现与手术病理结果进行对照,并由双盲法分析确认.结果 28例中,X线和CT显示广泛骨质破坏16例,骨膜反应22例.X线显示软组织肿块18例,肿瘤骨和瘤样钙化12例.CT平扫显示软组织肿块22例,增强扫描显示软组织肿块24例,肿瘤骨和瘤样钙化16例.MRI显示骨质破坏和骨膜反应10例,软组织肿块26例,其周围可见软组织水肿及骨髓水肿.骨膜反应在SE T1WI上呈等低信号,T2WI呈等信号.软组织肿块在T1WI为等信号,T2WI及STIR呈等高信号.软组织水肿及骨髓水肿在T2WI及STIR呈高信号.MRI增强检查显示病灶均呈不均匀强化,骨髓水肿和软组织肿块均见强化.结论 X线、CT和MRI从不同方面反映长骨骨干骨肉瘤的影像病理特点,其发病率低,骨破坏范围大,无病理性骨折.成骨型骨干骨肉瘤较易诊断,溶骨型应与Ewing瘤、恶性巨细胞瘤等鉴别.

Abstract：

Objective To explore the findings of diaphysial osteosarcoma in long bone on X-ray,CT and MRI, and discuss their clinical features and manifestations for differential diagnosis. Methods Twenty-eight cases with diaphysial osteosarcoma in long bone proved by surgery and pathology were reviewed retrospectively. Eighteen tumors were located in the femur, 4 in fibula, 4 in humerus and 2 in tibia. All of the patients were examined by X-ray, CT and MRI. The imaging manifestations on X-ray, CT and MRI were analyzed, and the relationship of the imaging features with the pathological types was also observed. The imaging signs were correlated with the pathologic findings with a double blind method. Results Of the 28 cases, there were 16 cases with large bone destruction, 22 cases with periosteal reaction on X-ray and CT. On X-ray, 18 cases showed soft tissue mass and 12 cases with neoplastic bone and tumor calcification.While on CT, 22 cases showed soft tissue mass on plain scan and 2 more cases displayed soft tissue mass after the injection of contrast mediun. Sixteen cases showed neoplastic bone and tumor calcification on CT.On MRI, there were 10 cases with bone destruction and periosteal reaction with iso- and hypo-intense on T1WI and iso- signals on T2WI. Twenty-six cases showed soft tissue edema and bone marrow on MRI. The soft mass were iso-signals on T1 WI and iso-hyperintense signals on T2 WI or STIR. The soft tissue edema was found hyperintense signals on T2WI or STIR. The lesions had heterogeneous enhancement especially in bone marrow with edema and adjcent soft tissue. Conclusion The X-ray, CT and MRI can reflect the pathological changes of diaphysial osteosarcoma in long bone from different aspects. Lower incidence, large bone destruction and no pathological fracture were the features of diaphysial osteosarcoma. The osteogenic type is diagnosed easily, but the osteolytic lesion should be differentiated from Ewing sarcoma, malignant giant cell tumor of bone and so on.     

健康成人皮下注射重组人粒细胞集落刺激因子后骨髓变化的MRI表现

目的：探讨健康成人受重组人粒细胞集落刺激因子(rhG-CSF)注射前后腰椎和股骨近端骨髓MRI的变化特点。方法 对20名健康成人干细胞捐献者行SE T1 WI及T2 WI-脂肪抑制序列,分别在皮下注射rhG-CSF前,注射后近期(4～7 d)、注射后中远期（30 ～60 d,10名）行腰椎矢状面、股骨中上段骨髓正冠状面MRI,研究和总结各时间段腰椎和股骨近端骨髓变化的特点。对比度信噪比(CNR)组间比较采用秩和检验。结果 正常对照组骨髓像设为注射前腰椎、股骨近端骨髓MRI。20名rhG-CSF注射后近期组SE T1WI腰椎骨髓信号呈均匀降低,同时椎体内带状、片状高信号的脂肪成分明显减少,股骨近端转子间及下方见条带状或小片状等或稍低信号灶,T2WI-脂肪抑制序列骨髓呈等或稍高信号,同一捐献者腰椎、股骨近端骨髓MRI异常信号灶同时出现。10名中远期组腰椎骨髓MRI与20名注射前组对比大致相同,而与注射后近期组对比,异常信号灶已基本恢复到注射前水平;但股骨近端骨髓MRI注射后中远期组与注射前组对比可见异常信号,表现为对称性带状或大片状SET1 WI等或稍低信号灶,T2WI-脂肪抑制序列呈等或稍高信号,而与注射后近期组对比,异常信号灶可见向远端延伸、扩展现象。20名rhG-CSF注射前组CNR为114.11±15.11,近期组为71.04±12.25,10名注射后中远期组为91.64±11.68,注射前组与注射后近期组比较差异有统计学意义(P＜0.05),注射前组与注射后中远期组、注射后近期组与注射后中远期组CNR分别比较,差异均无统计学意义（P值均＞0.05）。结论 注射rhG-CSF后,MRI可显示注射后近期骨髓内造血细胞和脂肪成分的变化,可为临床或骨髓移植提供骨髓变化时间与程度的无创性信息。     

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.     

Diagnostik des Plasmozytoms mit der MRT

Background. In multiple myeloma 5 different infiltration patterns can be differentiated: 1. normal appearance of bone marrow, 2. focal involvement, 3. homogeneous diffuse infiltration, 4. combined diffuse and focal infiltration, 5. “salt- and pepper” pattern with inhomogeneous bone marrow with interposition of fat islands. Methods. For the fast and total acquisition of all patterns a combination of a T1-weighted spin echo sequence and a fat suppression technique is superior. The focal involvement is clearly demonstrated as areas of high signal intensity on e. g. STIR images. Diffuse involvement can be quantified objectively by calculation of the percentage of signal intensity increase after contrast material injection. MRI is superior to X-ray in focal and diffuse involvement. With ultrafast sequences a “screening” of the whole red bone marrow as for myeloma infiltration is possible. Prognosis. In prognosis studies diffuse infiltration is inferior to focal involvement. Patients without bone marrow infiltration have a significantly longer survival than patients with bone marrow infiltration in MRI at the time of diagnosis. However, even patients in stage one of disease (Durie and Salmon) and negative X-ray films can show bone marrow infiltration in MRI. Those patients often show an early disease progression. Good response to therapy in focal involvement are: reduction of signal intensity on T2- weighted spin echo images, lack or rim- like enhancement after contrast material injection or even a normalisation of bone marrow signal. In case of diffuse involvement a partly patchy reconversion to fatty marrow can be seen.     

Role of MRI for the diagnosis and prognosis of multiple myeloma

For the correct staging of patients with multiple myeloma sensitive detection is mandatory in order to estimate prognosis and to decide for adequate therapy. Magnetic resonance imaging (MRI) is superior to radiography for both, focal and diffuse involvement. Five different infiltration patterns can be differentiated: (1) normal appearance of bone marrow despite minor microscopic plasma cell infiltration, (2) focal involvement, (3) homogeneous diffuse infiltration, (4) combined diffuse and focal infiltration, (5) "salt-and-pepper"-pattern with inhomogeneous bone marrow with interposition of fat islands. For the fast and complete assessment of all patterns a combination of a T1-weighted spin echo sequence and a fat suppression technique should be employed. The focal involvement is clearly demonstrated as areas of high signal intensity on, e.g. STIR images. Diffuse involvement is best detected on unenhanced T1-weighted SE sequences and it manifests as homogeneous signal reduction. It can be quantified objectively by calculation of the percentage of signal intensity increase after contrast material injection. With parallel imaging and special coil devices, such as total imaging matrix (Siemens systems, Avanto) a "screening" of the whole red bone marrow as for myeloma infiltration is possible within a reasonable time. Patients without bone marrow infiltration have a significantly longer survival than patients with bone marrow infiltration in MRI at the time of diagnosis. However, even in stage I disease (Durie and Salmon) and negative X-ray films bone marrow infiltration in MRI may be detected in 29-50% of patients. Those patients typically show an earlier disease progression. Recently, MRI has been implemented in the clinical staging of patients with multiple myeloma. MRI may also monitor response to therapy. Signs of good response in cases with focal involvement are: reduction of signal intensity on T2-weighted spin echo images, lack or rim-like enhancement after contrast material injection or even a normalisation of bone marrow signal. In case of diffuse involvement a partly patchy reconversion to fatty marrow can be seen.     

Staging des multiplen Myeloms mit der MRT: Vergleich zur MSCT und zur konventionellen Röntgendiagnostik

The staging of patients with multiple myeloma demands sensitive imaging methods for the assessment of the skeletal system. MRI allows for direct visualization of the bone marrow which exhibits five different infiltration patterns in multiple myeloma: 1. normal appearance of the bone marrow, 2. focal involvement, 3. homogeneous diffuse infiltration, 4. combined diffuse and focal infiltration, 5. "salt and pepper" pattern with inhomogeneous bone marrow signals due to multiple fat islands. The combination of T1w-SE and STIR sequences is best suited for detecting all infiltration patterns and for the differential diagnoses e. g. hemangiomas. With parallel imaging in MRI, acquisition times can be markedly reduced and whole-body screening of the bone marrow can be achieved within 30 min. MRI is superior to radiography for the detection of focal as well as diffuse infiltration. Multidetector computed tomography and especially 16- and 64-detector row scanners allow fast imaging with thin slice collimation and multiplanar reconstructions. With low-dose protocols, effective dose reduction can be achieved, so that radiation exposure is only slightly higher than that of a whole-body skeletal x-ray exam. Sensitivity of MSCT is markedly superior to conventional radiography. Due to the direct visualization of the bone marrow with MRI, MRI is superior in detecting early infiltrations with myeloma cells without osteolyses. In advanced multiple myeloma, CT on the other hand, enables for more precise assessment of bony destructions and fracture risk.     

Bone marrow changes following radiotherapy. Results of MR tomography]

Magnetic resonance imaging (MRI) offers a new approach in the morphologic evaluation of the bone marrow. Physiologic and pathologic changes can be assessed with very high sensitivity. Radiotherapy induces acute depletion of the hematopoietic bone marrow, resulting in fatty degeneration. With MRI it is possible to evaluate the changes during irradiation and it also discloses the long-term fatty degeneration after radiotherapy. The irradiated bone marrow mostly exhibits a homogeneous hyperintense pattern on T1-weighted images. This allows clear recognition of the former target volumes. Our quantitative studies based on chemical shift imaging data reveal a lack of recovery of hematopoiesis after radiotherapy with 30 Gy or more. These results are independent of patients' age and of the interval after radiotherapy.     

Monitoring radiation-induced changes in bone marrow histopathology with ultra-small superparamagnetic iron oxide (USPIO)-enhanced MRI.

The purpose of this study was to monitor radiation-induced alterations of the blood-bone marrow barrier (BMB) and the reticuloendothelial system (RES) with AMI-227-enhanced magnetic resonance imaging (MRI). Twenty New Zealand white rabbits (n = 10 following total body irradiation and n = 10 controls) underwent AMI-227-enhanced MRI. Pulse sequences included dynamic fast low-angle shot (FLASH; TR/TE 50/4 msec, flip angle 60 degrees) MRI and static T1- and T2-weighted spin-echo (SE) and turbo-SE sequences of the lumbar spine and sacrum. Bone marrow enhancement was quantified as delta signal intensity (SI) (%) =|[(SIpost - SIpre)/SIpre] x 100%| and compared with histopathology, including iron stains and electron microscopy. Dynamic bone marrow deltaSI (%) data steadily increased up to 10-15 minutes after AMI-227 administration, while blood deltaSI (%) data stayed nearly constant, histologically corresponding to iron oxide leakage into the bone marrow interstitium. This bone marrow contrast enhancement increased significantly following irradiation, corresponding to alterations of the endothelial lining of the bone marrow sinusoids. Late postcontrast images exhibited a significant positive T1 enhancement and negative T2 enhancement of the normal bone marrow, which further increased with irradiation due to increased RES activity. Irradiation-induced changes in bone marrow physiology could be reliably assessed with AMI-227-enhanced MRI.     

MR imaging of diffuse bone marrow replacement in pediatric patients with cancer

In the magnetic resonance (MR) imaging examinations of three children with tumors (two neuroblastoma, one rhabdomyosarcoma) and three with leukemia, the marrow demonstrated a diffuse, uniform pattern of hypointensity on T1-weighted images and hyperintensity on T2-weighted images. The authors observed that this reversal ("flip-flop") of the usual MR characteristics of fatty marrow was seen in the epiphyses, metaphyses, and diaphyses. The purpose of this study was to establish the radiographic and clinicopathologic correlates of this MR finding on the basis of findings from plain radiographs, bone scans, and bone marrow aspirates. Plain radiographs and bone scans demonstrated either normal findings or changes limited to the metaphyses. In all patients, analysis of bone marrow aspirates demonstrated metastases. The authors concluded that even in the absence of evidence of discrete bone metastases on a plain radiograph or a bone scan, this diffuse and uniform "flip-flop" pattern reflects diffuse marrow replacement by tumor cells.     

Therapieinduzierte Effekte am Normalgewebe

More than 50% of cancer patients survive for more than 5 years, owing to modern and effective treatment. Therefore, long-term sequelae of treatment are more frequently seen than in the past. Such effects on normal tissue may both mimic and obscure tumor recurrences. Besides the direct consequences of surgery, tissue damage due to radiation or chemotherapy frequently cause problems in differential diagnosis. Among the numerous sequelae of radiotherapy, the most prominent are disturbance of the blood-brain barrier, radiation pneumonitis, osteodystrophy and osteoradionecrosis, fatty changes of bone marrow, or increased radiodensity of breast parenchyma. Chemotherapy may cause, e.g., diffuse abnormalities of white matter, pneumonitis and lung fibrosis, cardiomyopathy, or diffuse and patchy changes in bone marrow signals in MRI. The most devastating long-term complications are secondary cancers and leukemia induced by both radiotherapy and chemotherapy.     

Effect of granulocyte-stimulating factors on marrow of adult patients with musculoskeletal malignancies: incidence and MRI findings

OBJECTIVE: Our goal was to determine the incidence and pattern of red marrow reconversion on MRI of adults receiving granulocyte-stimulating factors as part of their chemotherapy regimen for primary musculoskeletal neoplasms and correlate the changes with WBC counts. MATERIALS AND METHODS: Twenty-five adults with soft-tissue sarcomas (n = 15) or primary bone tumors (n = 10) who underwent chemotherapy that included granulocyte-stimulating factors formed the study group. Two radiologists retrospectively evaluated the MRI studies by consensus before and after therapy to determine the presence of changes consistent with red marrow reconversion. Changes were categorized by appearance on T1- and T2-weighted images for location, pattern, and extent of marrow involvement. WBC counts at the time of MRI were recorded. Records were examined for evidence of marrow-infiltrating tumors or metastases. RESULTS: Ten (40%) of the 25 patients underwent bone marrow changes consistent with red marrow reconversion. In seven (70%) of 10 patients, the changes were diffuse in visualized bones and simulated diffuse marrow-infiltrative tumor. In three (30%) of 10 patients, the changes were focal, simulating metastases. T2 signal prolongation was identified in the marrow reconversion in nine patients (90%), although all had shortened T1 signal. Four patients (40%) had elevated WBC counts at the time of the MRI after therapy, but all had shortened T1 signal. Four patients (40%) had elevated WBC counts at the time of the MRI after therapy, five (50%) had normal counts, and one (10%) had a below-normal count. No osseous metastases or marrow-infiltrating tumors were found during follow-up. CONCLUSION: Forty percent of patients showed marrow changes mimicking tumor on MRI that were attributable to red marrow reconversion, which correlated moderately with WBC response.     

Tc-99m depreotide SPECT demonstrates photon-deficiency in the thoracic vertebrae after adjunct radiation therapy of lung cancer: Correlation with MRI and bone scintigraphy

Fifteen months after right lobe lobectomy with adjunctive radiation therapy for squamous cell carcinoma, a patient 53-yr-old man underwent Tc-99m depreotide chest single photon emission tomography (SPECT). In addition to two focal areas of abnormally increased uptake in the right lung, the Tc-99m depreotide SPECT showed cold areas in the middle thoracic vertebrae. Photopenic areas in the 6th and 7th thoracic vertebrae were shown on a bone scintigraphy. T1 weighted magnetic resonance imaging (MRI) of the spine showed fatty replacement of the marrow and Schmorl's nodes involving the 5th to 11th thoracic vertebrae. The vertebrae are normally visualized in Tc-99m depreotide SPECT imaging study, and lung tumor is usually somatostatin receptor positive with demonstrable activity in the lung. Absent uptake in the vertebrae in the fatty replacement of the marrow and multiple and giant vertebral Schmorl's nodes in the correspondent vertebrae in MRI may reflect visualization of vertebrae due to Tc-99m depreotide localizing in the bone marrow. Of the three imaging modalities, MRI showed the widest areas of thoracic vertebral involvement. One should be aware that a cold lesion in the vertebrae on Tc-99m depreotide imaging study may result from irradiation and may indicate the presence of a benign lesion in the bone marrow.     

Bone marrow edema pattern around the knee on magnetic resonance imaging excluding acute traumatic lesions

Magnetic resonance imaging (MRI) is very sensitive for the detection of marrow abnormalities. Bone marrow edema on MRI has been defined as an area of low signal intensity on T1-weighted images, associated with intermediate or high signal intensity findings on T2-weighted images. The bone marrow edema pattern is a nonspecific finding with multiple etiologies. The knee is a common place for bone marrow signal abnormalities to appear on MRI. Besides contusions and fractures from acute trauma, there are a variety of other causes of the bone marrow edema pattern. It is important for the interpreter of the study to be aware of the different etiologies responsible for producing these changes and to be able to narrow the differential diagnosis without mistaking such a pattern for acute trauma or infiltrative tumor. This article concentrates on those entities that produce a bone marrow edema pattern not related to acute trauma including red marrow proliferation, stress, osteochondral lesions, osteonecrosis, bone marrow edema syndrome, arthropathy, infection, Paget's disease, and marrow replacement disorders.     

儿童急性白血病四肢骨关节的影像研究

目的 探讨急性白血病儿童患者四肢骨关节的X线和MRI特点.方法 搜集以骨关节疼痛为主诉,经临床及骨髓穿刺确诊为急性白血病的13例患儿,对其疼痛部位均行X线平片检查,8例同时行MR检查,其中4例经过化疗达完全缓解后1周内行原疼痛部位的X线和MRI复查.对2种不同影像表现进行分析.结果 13例中,6例X线表现正常,7例共14处可见骨质异常:十骺端透亮带5处,骨膜反应3处,混杂密度骨质破坏1处,浸润性骨质改变3处,骨质疏松2处.MR检查8例共11处,6例共9处MRI表现为骨髓浸润、坏死,X线表现正常;2例共2处MRI表现为骨髓浸润,X线可见骨膜反应及干骺端透亮带.4例化疔达完全缓解后1周内复查,MRI显示骨髓浸润、坏死病灶范围缩小并T1WI骨髓信号不均匀增高,坏死灶呈较均匀长T1、长T2信号,边界清晰,双边征消失,相同病例治疗前后X线复查未见明显改变.结论 以骨关节痛为主诉的急性白血病患儿,MRI较X线能更早期、全面地检测到骨关节的病变,MRI可作为临床疗效监测的指标之一.

Abstract：

Objective To evaluate X-ray and MRI features of limbs in childhood acute leukemia.Methods Thirteen children with acute leukemia in our pediatric hematology ward were recruited.Allpatients were pathologically diagnosed by bone marrow aspiration and complained of bone or joint pain in the first visit.ConventionaI X-ray and MRI examinations of algesic sites were performed before clinical treatment and after complete remission.MR images were obtained with SE-T1WI,SE-T2WI and T2WI-fat suppressed sequences and symmetria bilateralis was requested while scanning.X-ray and MRI manifestations were evaluated and compared.Resuits All 13 patients had received X-ray examinations.Among them,6 had normal X-ray findings,whereas the other 7(14 sites)showed various abnormalities including radiolucent metaphyseal bands(5 sites),periosteal reaction(3 sites),osteapenia(2 sites),mixed lesions(lysissclerosis,1 site),and permeative pattern(3 sites).The number of patients for MRI examinations was 8(11 sites).Among them,6(9 sites)showed bone marrow infiluration and bone marrow necrosis accompanied by normal X-ray findings,another 2(2 sites)showed bone marrow infiltration associated with radiographic abnormalities of periosteal reaction and radiolucent metaphyseal bands.Four cases were followed up within 1 week when reached complete remission by chemotherapy.MR images features included reduced sizes of bone marrow infiltration lesions associated with increased signal intensity on T1WI,and disappearance of double-line sign on bone marrow necrosis accompanied by signal homogenization.However,the radiograph before and after treatment in the same cases did not differ significantly.Conclusions MRI was earlier and more comprehensive in showing limbs bone marrow abnormality than radiogram in acute leukemia children with chief complaint of osteoarticular pains.MRI might be one of indicators in following up therapeutic effect for AL children with osteoarticular disorder.     

全身MRI与PET/CT在淋巴瘤骨髓浸润诊断及预后中的作用

淋巴瘤是一种血液系统恶性肿瘤。淋巴瘤骨髓浸润(BMI)使疾病分期上升至IV期, 是疾病进展、预后较差的标志。常规部位的骨髓活检(BMB)具有创伤性, 且检出率低。PET/CT与全身MRI的出现, 丰富了BMI的检测手段。PET/CT与全身MRI对于淋巴瘤, 尤其是侵袭性淋巴瘤BMI均具有较高的检出率, 二者孰高孰低, 尚未定论。对于红骨髓、良性骨髓病变(炎症等)、淋巴瘤BMI病灶以及肿瘤治疗后骨髓的变化与骨髓残留或复发病灶, 全身MRI很难区分, 而PET/CT却可以很好地鉴别这些病灶。但是, PET/CT存在电离辐射; 对于惰性淋巴瘤的BMI, 超出PET/CT分辨率的病灶, 可能出现假阴性; 某些情况会限制PET/CT的使用, 包括18F-FDG生理性摄取量可能发生改变的正常组织、18F-FDG摄取相关性炎症、高血糖或高胰岛素血症导致的18F-FDG分布的改变、肿瘤患者治疗后出现的骨髓活化等。然而, 这些情况可以使用全身MRI。因此, 全身MRI和PET/CT相辅相成, 优势互补, 但二者均不能代替BMB。对于常规BMB阴性, 但影像学提示阳性的患者, 在影像学引导下进行BMB, 可以提高BMI的检出率。另外, 全身MRI阳性的淋巴瘤BMI患者与全身MRI阴性的淋巴瘤BMI患者相比, 前者预后可能较差。     

Imaging of malignant bone involvement by morphologic, scintigraphic, and hybrid modalities.

Detection of bone involvement is essential for optimal therapy of oncologic patients. The purpose of imaging is to identify early bone involvement, to determine the full extent of the skeletal disease, to assess the presence of accompanying complications-such as fractures and cord compression-and to monitor response to therapy. Detection of bone involvement by various imaging modalities is based on either direct visualization of tumor infiltration or detection of the reaction of bone to the malignant process. MRI can identify early involvement of bone marrow. CT, which depends mainly on bone destruction, provides detailed bone morphology. In nuclear medicine, uptake of (18)F-FDG is directly into tumor cells, thus allowing for early detection and monitoring the response to therapy of tumor sites in the marrow, bone, and soft tissue, whereas increased uptake of (18)F-fluoride and (99m)Tc-methylene diphosphonate reflects the osteoblastic reaction of bone to the presence of tumor cells. The hybrid techniques SPECT/CT and PET/CT, recently introduced into clinical practice, provide a better anatomic localization of scintigraphic findings and may improve the diagnostic accuracy of SPECT and PET in detecting malignant bone involvement. The current review discusses the basis for the detection of malignant bone involvement by various morphologic and scintigraphic imaging modalities and the advantages and the limitations of each. Special emphasize is placed on the newer integrated technique of PET/CT. The role of imaging in identifying bone involvement in different malignant diseases is also discussed.     

Evaluation of an ultrasmall superparamagnetic iron oxide in MRI in a bone tumor model in rabbits

Ultrasmall superparamagnetic iron oxides (USPIOs) are a class of MRI contrast agents having moderately selective affinity for the reticuloendothelial cells of lymph nodes and bone marrow. This study evaluated a USPIO preparation, Combidex (Code 7227), in MRI of a rabbit bone tumor model. VX2 carcinoma implanted into the tibial marrow of nine subject rabbits was studied. After tumor growth, the subjects underwent MRI of their lesions both before and after intravenous administration of Code 7227. Code 7227 was judged subjectively to conspicuously reduce the signal intensity of normal marrow on some pulse sequences. A hypointense zone outlined the tumor margins on postcontrast imaging, which allowed improved visualization of the soft tissue component of the larger lesions. Accumulation of the contrast agent in a zone of inflammation outside the tumor margin was demonstrated on histologic sections of the lesions. Code 7227 deserves additional study as a potential contrast agent for MRI of bone tumors.     

Magnetic resonance imaging of musculoskeletal neoplasms

MRI has been shown to be very useful in the work-up of musculoskeletal neoplasms. The lack of ionizing radiation, the superb contrast resolution, and the ability to directly scan the sagittal and coronal planes make MRI a very attractive imaging mode for treatment planning. With spin-echo MRI, maximum contrast between tumor and fatty tissues generally occurs with short TR and TE times (T1-weighted images). Likewise, maximum contrast between tumor and muscle, tendon, or ligaments occurs with long values of TR and TE (T2-weighted images). Early experience suggests that the already exceptional contrast resolution seen with MRI can be improved even more with the administration of intravenous contrast agents. Just as with CT, fatty tumors can usually be easily distinguished from other tissue types with MRI by means of their differential intensity behavior at different pulse sequences. Fluid-filled tumors, such as unicameral bone cysts or aneurysmal bone cysts may be suspected in the same manner, especially if a fluid-fluid level is seen within the lesion. Otherwise, MRI has not been useful so far in noninvasively determining the histologic type of tumors. Our experience and that of others suggests that MRI is equal or superior to CT in the work-up of musculoskeletal neoplasms. This is especially striking when it is remembered that one is comparing an immature MRI technology with a mature CT technology. Although CT presently has a central role in the staging of musculoskeletal tumors, MRI will shortly supplant it in many cases.     

Monitoring bone marrow‐originated mesenchymal stem cell traffic to myocardial infarction sites using magnetic resonance imaging

How stem cells promote myocardial repair in myocardial infarction (MI) is not well understood. The purpose of this study was to noninvasively monitor and quantify mesenchymal stem cells (MSC) from bone marrow to MI sites using magnetic resonance imaging (MRI). MSC were dual‐labeled with an enhanced green fluorescent protein and micrometer‐sized iron oxide particles prior to intra‐bone marrow transplantation into the tibial medullary space of C57Bl/6 mice. Micrometer‐sized iron oxide particles labeling caused signal attenuation in T₂*‐weighted MRI and thus allowed noninvasive cell tracking. Longitudinal MRI demonstrated MSC infiltration into MI sites over time. Fluorescence from both micrometer‐sized iron oxide particles and enhanced green fluorescent protein in histology validated the presence of dual‐labeled cells at MI sites. This study demonstrated that MSC traffic to MI sites can be noninvasively monitored in MRI by labeling cells with micrometer‐sized iron oxide particles. The dual‐labeled MSC at MI sites maintained their capability of proliferation and differentiation. The dual‐labeling, intra‐bone marrow transplantation, and MRI cell tracking provided a unique approach for investigating stem cells' roles in the post‐MI healing process. This technique can potentially be applied to monitor possible effects on stem cell mobilization caused by given treatment strategies. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.     

Magnetic resonance imaging of the lower vertebral column in patients with multiple myeloma

Eighteen patients with multiple myeloma (clinical stages 1-3) and a control group of 21 persons underwent magnetic resonance imaging (MRI) studies of the lower thoracic and lumbar spine. This was done to determine the potential benefit of MRI in addition to conventional radiographs, tomograms, computed tomography and nuclear scans. In addition to focal fatty replacement of normal hematopoietic marrow, which presented as focal hyperintense lesions on T1-weighted images (T1-WI) and on T2-weighted images (T2-WI), two types of myelomatous lesions were found: (1) focal areas with reduced signal intensity when compared with normal bone marrow on T1-WI and enhanced signal intensity on T2-WI, mainly found in untreated myelomas; and (2) focal areas of decreased signal intensity on T1-WI and on T2-WI, which were predominantly detected after previous radiation therapy. MRI surpassed conventional radiography in detecting abnormal focal marrow infiltration in 41 of 247 vertebrae. Radiographs identified only 11 of the 41 as pathologic, based on shape and structure of the vertebral bodies; however, 15 other collapsed vertebrae showed no signal abnormalities of the marrow on MR images. Discrimination of normals and abnormals by statistical analysis of intensity measurements of the bone marrow was not possible.