B. Maldague

Magnetic resonance imaging of normal bone marrow.

Abstract. The appearance in magnetic resonance imaging (MRI) of the bones depends, to a large extent, on the unmineralized content of the bone cavities. Because yellow marrow contains a large number of fat protons and red marrow a significant number of water protons, MRI offers the opportunity to map the distribution of red and yellow marrow. In addition, red marrow MR appearance varies according to the relative proportion of fat and nonfat cells. Variations in the composition of red marrow and its distribution among normal subjects, mainly in relation to age and sex, contribute to creating a wide spectrum in bone MR appearance, which must be known in order to avoid confusion with bone marrow abnormalities.

Magnetic resonance imaging of the bone marrow in hematological malignancies

Abstract. Despite its lack of specificity, magnetic resonance imaging (MRI) of the bone marrow has the potential to play a role in the management of patients with primary neoplastic disorders of the hematopoietic system, including lymphomas, leukemias and multiple myeloma. In addition to its use in the assessment of suspected spinal cord compression, bone marrow MRI could be used as a prognostic method or as a technique to assess the response to treatment. The current review addresses the common patterns of bone marrow involvement observed in primary neoplasms of the bone marrow, basic technical principles of bone marrow MRI, and several applications of MRI in selected clinical situations.

Ferumoxides-enhanced quantitative magnetic resonance imaging of the normal and abnormal bone marrow: preliminary assessment.

The purpose of our study was to assess the effects of intravenous administration of ferumoxides on normal and abnormal vertebral bone marrow T1 and T2 relaxation times. Changes in bulk T1 and T2 relaxation times induced by intravenous administration of ferumoxides were determined in the normal vertebral marrow of two healthy subjects and four patients. In the four patients, changes in bulk T1 and T2 values induced by furomoxides injection were also determined in 12 vertebral metastases. Relative to precontrast relaxation time values, bulk T1 and T2 values of normal bone marrow had declined by a mean of 24% and 19%, respectively, in the two subjects and the four patients 45 minutes after ferumoxides administration. Relative to precontrast values, bulk T1 and T2 values of abnormal bone marrow had decreased by a mean of 16% and 2%, respectively. Decreases in bulk T1 and T2 values in normal bone marrow and in bulk T1 values in metastases were statistically significant (P < 0.001). Changes in bulk T2 values observed in metastases were not statistically significant. Quantitative MRI demonstrates that ferumoxides infusion induces a decrease in bulk T1 and T2 relaxation times of normal bone marrow. It also suggests a lack of T2 shortening in bone metastases.J. Magn. Reson. Imaging 1999;9:322–328.

Apparent focal bone marrow ischemia in patients with marrow disorders: MR studies.

Objective We sought to assess with MR the focal bone marrow abnormalities in patients with chronic marrow disorders and acute limb pain. Materials and Methods We investigated and followed with MRI four patients with proliferative or dysplastic marrow disorders presenting with acute but spontaneously resolving hip or thigh pain. Results Ten focal marrow lesions were demonstrated on T2-weighted images as high signal intensity (SI) areas. They remained undetected on T1-weighted images as they showed a low SI similar to the disease-related low SI of the entire marrow. Postcontrast images demonstrated lack of enhancement in the lesions. Follow-up enhanced MR images showed intense enhancement within the lesions, while unenhanced MR images remained unchanged. Later on, these focal marrow abnormalities completely resolved. These lesions most likely represent bone marrow ischemia, although histological proof is lacking. Conclusion Acute bone pain in patients with bone marrow disorders may be related to focal marrow lesions suggestive of bone marrow ischemia.

MRI of the spine in cobalamin deficiency: the value of examining both spinal cord and bone marrow.

We observed a case of pernicious anaemia in which MRI of the spine demonstrated both intrinsic lesions of the spinal cord and abnormal signal in the bone marrow. The latter resolved with replacement therapy. Only partial recovery of the cord lesions was observed.

Case report : elastofibroma dorsi : a pseudomalignant lesion

Elastofibroma dorsi is an uncommon soft tissue lesion that appears in elderly individuals as a mass in the chest soft tissues, just anterior to the tip of the scapula [1-3]. Recent reports have shown MR and CT features such as ill-defined margins and heterogeneous signal or density which may suggest an aggressive lesion [4-7]. This case report presents the morphologic and signal characteristics of elastofibroma dorsi on MR that allow a prospective diagnosis to be made.

Imaging of Bone Marrow Disorders

The objectives of this chapter are three-fold. First, the reader will become familiar with the magnetic resonance (MR) appearance of both the normal bone marrow and its variants. Second, a logical analysis of MR imaging (MRI) patterns of elementary lesions will be offered. Finally, the opportunity to analyze MR images of patients with bone metastases, multiple myeloma or lymphoma, with emphasis on lesion detection, will be provided.

Maladie de paget : diagnostic positif et differentiel

Objectifs Presenter la semeiologie typique de la maladie de Paget dans les differentes methodes d’imagerie. Preciser les criteres permettant d’en etablir le diagnostic positif. Preciser les elements qui permettent d’exclure ce diagnostic. Messages a retenir L’aspect radiologique du remaniement osseux local est suffisamment typique pour permettre un diagnostic positif dans la plupart des cas. La distribution de l’affection est egalement caracteristique : atteinte d’une partie ou de la totalite d’un ou plusieurs os, mais pas pathologie diffuse. La moelle osseuse est en principe normale ou quasi normale, a l’inverse de la plupart des autres affections osseuses condensantes. Les sequences d’IRM avec suppression du signal de la graisse peuvent objectiver des anomalies subtiles. Resume L’os pagetique est caracterise par une organisation particuliere, consequence d’une activation considerable du remaniement osseux. Les modifications portent sur la densite (resorption initiale puis hyperdensite), la structure (os cortical poreux, os spongieux epaissi, dedifferentiation corticospongieuse), la forme (hypertrophie, deformations plastiques). Le remaniement pagetique debute dans une portion de l’os et s’etend de proche en proche (de pres d’un cm par an). En cas de doute, la cle du diagnostic differentiel se trouve dans l’analyse du contenu medullaire qui est quasi normal, a l’inverse de la plupart des lesions osseuses (neoplasiques, inflammatoires) dont l’atteinte primaire est intramedullaire.

Hyperparathyroidie (HPT) et osteodystrophie renale (ODR)

Objectifs Pouvoir identifier la resorption osseuse typique de l’HPT. Dans l’ODR, pouvoir determiner les fluctuations du remaniement osseux et de la calcinose arterielle. Situer la place des differents procedes d’evaluation de l’ODR. Messages a retenir La resorption osseuse pathognomonique de l’HPT predomine au versant radial des phalanges moyennes et au niveau des houppes phalangiennes distales. Les contraintes mecaniques la focalisent selon nous a ces niveaux, de meme qu’en territoire sous-chondral, et au niveau des entheses. Dans l’insuffisance renale chronique, les cliches sequentiels illustrent les fluctuations de la resorption osseuse et de la calcinose metabolique. Resume Le diagnostic d’hyperparathyroidie primitive est biologique et donc pre-radiologique. Cependant, l’osteite fibrokystique secondaire ou tertiaire, associee a des tumeurs brunes, est loin d’avoir disparu. Sa decouverte par l’imagerie est parfois insolite. Dans l’insuffisance renale chronique, malgre les progres des dosages biologiques et de l’histomorphometrie, la radiographie conserve un role significatif dans la demonstration de l’HPT secondaire, voire tertiaire, et le suivi de leur evolution. Par ailleurs, le degre de calcinose arterielle associee a l’osteodystrophie renale est desormais considere comme un indicateur de risque important. Chez l’insuffisant renal, les fluctuations de la calcinose doivent donc etre evaluees aussi precisement que possible, radiologiquement ou au scanner.

2108 Approche radiologique elementaire des tumeurs osseuses et applications aux lesions « a laisser tranquilles »

Objectifs pedagogiques Decrire la signification des differents signes elementaires d’analyse des tumeurs osseuses et appliquer ces principes au diagnostic des tumeurs ou pseudo-tumeurs osseuses qui peuvent etre « laissees tranquilles » : kystes simples, lacunes fibreuses, enchondromes et tutti quanti.