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Biomedical subjects

D Jaramillo

Publications and source records attributed to D Jaramillo.

At least 19 recordsLinked to original sources
PubMed2005

Diagnostic criteria for schwannomatosis.

The neurofibromatoses are a diverse group of genetic conditions that share a predisposition to the development of tumors of the nerve sheath. Schwannomatosis is a recently recognized third major form of neurofibromatosis (NF) that causes multiple schwannomas without vestibular tumors diagnostic of NF2. Patients with schwannomatosis represent 2.4 to 5% of all patients requiring schwannoma resection and approximately one third of patients with schwannomatosis have anatomically localized disease with tumors limited to a single limb or segment of spine. Epidemiologic studies suggest that schwannomatosis is as common as NF2, but that familial occurrence is inexplicably rare. Patients with schwannomatosis overwhelmingly present with pain, and pain remains the primary clinical problem and indication for surgery. Diagnostic criteria for schwannomatosis are needed for both clinicians and researchers, but final diagnostic certainly will await the identification of the schwannomatosis locus itself.

Diagnosis, Differential↗
PubMed2001

Protocol issues for delayed Gd(DTPA)(2-)-enhanced MRI (dGEMRIC) for clinical evaluation of articular cartilage.

Biochemical and histologic data have validated the technique of delayed gadolinium-enhanced MRI, in which the T(1) values of cartilage after penetration of Gd(DTPA)2-allow assessment of the glycosaminoglycan (GAG) component of articular cartilage. This work describes the factors that have been found to be important for the practical implementation of the technique: 1) Exercise immediately after intravenous contrast administration was necessary for effective penetration of the contrast into the articular cartilage; 2) double-dose contrast was better than single-dose; 3) after contrast administration, a time window of 30-90 min for the hip, and 2-3 hr for all compartments of the knee proved to be appropriate for assessing articular cartilage; and 4) in some cases of hypointensities in the subchondral patellar bone, decreased penetration of the contrast agent into cartilage from bone was found. With the protocol described, ROIs on T(1) images were reproducible within 15% on two separate imaging sessions, and initial clinical studies demonstrated the possible applications of the technique. Magn Reson Med 45:36-41, 2001.

Cartilage, Articular↗
PubMed2001

Aggressive multimodal treatment of pleuropulmonary blastoma.

Pleuropulmonary blastoma is a rare intrathoracic neoplasm almost solely confined to childhood. Survival is poor. The authors report 2 children with extensive intrathoracic disease who are long term survivors after multimodal therapy. Both children received multiagent neoadjuvant chemotherapy, followed by surgical resection to remove all gross tumor. Postoperative chemotherapy was given to both children; radiotherapy was also given in the second case because of a question of positive tumor margins. Experience supports the use of multimodal therapy, including an aggressive surgical approach in the potentially curative treatment of this tumor.

Child↗
PubMed2001

Imaging of sports injuries in children and adolescents.

Imaging plays an important role in the diagnosis and management of sports injuries of childhood and adolescence. The injuries discussed are typical of those seen in the skeletally immature athlete. Imaging specialists must be able to apply the full range of imaging modalities when evaluating the injured young athlete.

Adolescent↗
PubMed2001

Imaging of growth disturbance in children.

Growth disturbance of the long bones in children is frequently post-traumatic but also occurs because of physeal, epiphyseal, or metaphyseal ischemia. The imaging features of growth arrest depend more on the anatomic site involved than on the cause. The physes of the distal tibia and femur and proximal tibia are disproportionately at risk because of their complex geometry. The central undulation in the distal femur and the bump in the anteromedial physis (Kump's bump) in the distal tibia are the sites of initial physiologic closure and the most frequent areas of premature fusion. The MR imaging features of growth disturbance are characteristic. T1-weighted images show low signal intensity GRL and variable signal intensity bony bridges. On GRE sequences, a bridge appears as low signal intensity interruption in the otherwise high signal intensity physeal cartilage. Physeal widening on GRE and T2-weighted images implies physeal dysfunction without bridge formation. Proton density and T2-weighted images best reveal associated metaphyseal and soft tissue changes. Regardless of the cause, MR imaging exquisitely depicts cartilaginous pathology at the physis. MR evaluation should be considered in patients at high risk for growth disturbance including young children with extensive residual growth potential; those with involvement of particularly vulnerable growth plates; and those with severe, complex fractures.

Child↗
PubMed2001

Fast three-point dixon MR imaging using low-resolution images for phase correction: a comparison with chemical shift selective fat suppression for pediatric musculoskeletal imaging.

OBJECTIVE: The purpose of this study is to describe and to implement a new fast three-point Dixon MR imaging sequence with online image reconstruction, and to compare this sequence with conventional chemical shift selective (CHESS) suppression of fat in pediatric musculoskeletal imaging. SUBJECTS AND METHODS: A three-point Dixon technique using a fast spin-echo sequence with a new phase-correction algorithm providing online image reconstruction was implemented on a 1.5-T scanner. Twelve pediatric patients and young adults were imaged with both the new three-point Dixon and conventional CHESS sequences. Three radiologists un-aware of imaging parameters and clinical information independently scored the homogeneity of fat suppression and conspicuity of abnormality using a four-point system. An additional comparison between the two techniques was made using a phantom. RESULTS: The three-point Dixon method showed superior fat suppression and lesion conspicuity (p < 0.001), particularly in the hands and feet, where CHESS is prone to inconsistent fat suppression. The phantom study showed no significant difference in the ratio of suppressed fat signal to background noise and more homogeneous fat suppression using the three-point Dixon method. CONCLUSION: Compared with CHESS, the new fast three-point Dixon sequence with online image reconstruction provides superior fat suppression and lesion conspicuity and can be routinely used in pediatric musculoskeletal imaging.

Adolescent↗
PubMed2001

Normal MR imaging anatomy of the ankle and foot in the pediatric population.

MR imaging demonstrates the cartilaginous primordia of the bones of the foot and ankle. Ossification of the round bones begins in a single center and extends along the length of the bone. There is a difference between the orientation of the ossification center and that of the main cartilaginous structure. MR imaging can show the zones of the cartilage and the changes that precede ossification. The changes in the cartilage and marrow at different ages are illustrated for the ankle, hindfoot, and midfoot.

Ankle↗
PubMed2000

Magnetic resonance imaging measurements of bone density and cross-sectional geometry.

Magnetic resonance imaging (MRI) is commonly used in the assessment of the musculoskeletal system and associated pathology. The ability of MRI to measure the signals from water and lipid protons enables quantitative measurements of bone porosity. The goal of this investigation was to demonstrate that the density and cross-sectional geometry of whole bones can be noninvasively measured using MRI. Ten trabecular specimens cored from whale vertebrae were used to compare apparent bone density measured directly, and using a quantitative MRI algorithm. Bone density and several cross-sectional geometric properties were also measured using MRI in the distal tibia of 14 volunteers. The MRI measurements were compared with measurements made using quantitative-computed tomography (QCT). A proton density sequence was used for all MRI studies. A porosity phantom was included in the MRI examinations and used to convert the MRI signal intensity to bone volume fraction. Bone density and cross-sectional bone geometry were calculated from the bone volume fractions by assuming constant tissue properties. The apparent density of trabecular bone cores measured directly and using quantitative MRI were linearly related (r(2) = 0.959; P < 0. 01). A strong linear relation also existed between MRI and QCT measurements of ash density (r(2) = 0.923; P < 0.01) and cross-sectional geometric properties (r(2) = 0.976-0.992; P < 0.01). MRI data can be used to measure bone density and cross-sectional geometry of whole bones if a proton density sequence is used to homogenize differences in marrow composition and a porosity phantom is used for slice-specific volume fraction calibration.

Adult↗
PubMed2000

Intraosseus teratoma of the iliac bone.

We present a 4-year-old child with a large iliac bone mass incidentally discovered in a plain abdominal radiograph. The pathological examination revealed a benign mature teratoma. To the best of our knowledge, the occurrence of intraosseous mature teratoma has not been previously reported. The child had had an immature teratoma of the neck discovered in a fetal ultrasound, and resected on day 6 of life. The neck teratoma recurred twice, at 16 months and at 3.5 years of age. In these two recurrences the lesion appeared progressively more mature. At the time of discovery of the iliac bone teratoma there was no evidence of residual neck disease. The radiological and pathological characteristics, differential diagnosis, and clinical course are discussed.

Age Factors↗
PubMed2000

Normal maturation of the distal femoral epiphyseal cartilage: age-related changes at MR imaging.

PURPOSE: To determine how signal intensity in the cartilaginous distal part of the femoral epiphysis varies with (a) age, (b) sex, and (c) distribution to the medial or lateral condyle on magnetic resonance (MR) images. MATERIALS AND METHODS: Sixty-six sagittal T2-weighted or inversion-recovery MR images of the distal femoral epiphysis in children aged 2 months to 5 years 5 months were evaluated. Epiphyses were categorized into five types on the basis of progressive signal intensity changes within the epiphyseal cartilage along the weight-bearing region and posterior condyles. Epiphyseal type was compared with age, sex, and distribution of signal intensity changes within the condyle. RESULTS: In early infancy, epiphyseal cartilage was homogeneous. During the 2nd year, signal intensity along the weight-bearing region decreased. With further advancing age, signal intensity in the posterior femoral condyles increased and became progressively more focal. The increase in epiphyseal grade correlated with age for both the medial and the lateral femoral condyles (r = 0.71 and r = 0.77, respectively; P < .001). There was no significant difference in epiphyseal changes between boys and girls or between medial and lateral condyles. CONCLUSION: There is normal age-related variation in MR imaging signal intensity within the cartilaginous epiphysis of the distal femur. This may be related to weight bearing and epiphyseal maturation and should not be confused with disease.

Bone Development↗
PubMed2000

Cartilaginous path of physeal fracture-separations: evaluation with MR imaging--an experimental study with histologic correlation in rabbits.

PURPOSE: To define the transverse levels of intracartilaginous fractures by using magnetic resonance (MR) imaging and histologic analysis in experimental physeal fracture-separations. MATERIALS AND METHODS: Physeal fracture-separations were evaluated with MR imaging in 28 distal femurs and 28 proximal tibias of 22 immature rabbits. The intraphyseal transverse level of injury was graded as juxtaepiphyseal (germinal or proliferative zones) or juxtametaphyseal (hypertrophic zone or zone of provisional calcification). Histologic sections from 23 specimens were studied to assess correlations. We assessed nonenhanced and gadolinium-enhanced T1-weighted, intermediate-weighted, T2-weighted, and spoiled gradient-recalled-echo T1-weighted images. RESULTS: In all MR studies, the injury was visible as a cleft of signal intensity lower than the signal intensity of the physeal cartilage. Juxtaepiphyseal extension, seen in 18 (64%) of 28 fractures, was more frequent in the undulating central part of the distal femoral physis than in the flatter proximal tibial physis (P =.008). In 20 of 23 specimens, MR imaging and histologic findings had excellent correlation for the detection of fracture level and morphology. CONCLUSION: The course and level of injury within the cartilage in physeal fracture-separations can be defined with MR imaging. Extension into the juxtaepiphyseal physis, a potential risk factor for growth arrest, is detectable with MR imaging; MR imaging and histologic findings correlate well.

Animals↗
PubMed1999

Rickets on MR images.

BACKGROUND: The pathologic changes at the physis in patients with rickets have been well demonstrated histologically. Radiographs can depict only the associated osseous abnormalities. PATIENTS AND METHODS: We report two children in whom MR imaging demonstrated rachitic changes in the physeal cartilage beyond the well-recognized bony features. RESULTS: The striking appearance of the physes and the physes of the secondary ossification centers confirm that MR imaging can successfully evaluate the cartilaginous structures of the developing skeleton. CONCLUSION: Though MR imaging is clearly unnecessary for the diagnosis of rickets, it is important that the typical features are not misinterpreted as other pathology.

Bone and Bones↗
PubMed1999

Spin-Echo planar spectroscopic imaging for fast lipid characterization in bone marrow.

Lipid characterization of bone marrow in vivo with proton magnetic resonance spectroscopy was performed using Spin-Echo Planar Spectroscopic Imaging sequences. The methods are shown capable of rapidly generating two-dimensional chemical shift imaging data sets suitable for measuring lipid indices that reflect unsaturation levels among triglycerides, as demonstrated in oil phantoms and bone marrow from a healthy volunteer. The volume coverage, spatial resolution, acquisition speed, and spectral characteristics of Spin-Echo Planar Spectroscopic Imaging should make it attractive for clinical studies of diseases affecting normal lipid chemical composition.

Adult↗
PubMed1999

Legg-Calvé-Perthes disease: MR imaging evaluation during manual positioning of the hip--comparison with conventional arthrography.

PURPOSE: To evaluate the use of magnetic resonance (MR) imaging during manual positioning of the hip, or multipositional MR imaging, in an open-magnet configuration to study femoral head containment, articular congruency, and femoral head deformity in Legg-Calvé-Perthes disease. MATERIALS AND METHODS: In 12 children with advanced Legg-Calvé-Perthes disease, multipositional MR imaging and conventional arthrography were compared in the assessment of containment, femoroacetabular congruency, and femoral head deformity. Images of the hips in several positions were compared subjectively and objectively. RESULTS: MR imging correlated well with arthrography for overall subjective assessment of severity of disease (r = 0.71, P = .01), with good interobserver agreement (kappa = 0.65, P < .001). MR images demonstrated all cases of hinge abduction shown arthrographically. However, MR imaging failed to depict one case of femoral head flattening. MR imaging correlated well with arthrography in the objective evaluation of joint fluid and lateral subluxation (r = 0.80, P < .01). MR imaging correlated poorly with arthrography in the measurement of sphericity of the femoral head. CONCLUSION: Multipositional MR imaging with an open-magnet configuration was comparable to arthrography for demonstration of femoral head containment and congruency of the articular surfaces of the hip. In the evaluation of deformity, it performed less well.

Arthrography↗
PubMed1998

Hip arthrography, aspiration, block, and bursography.

Hip arthrography in children with Legg-Calvé-Perthes disease is used to determine the optimal position of the femoral head for immobilization during the process of epiphyseal healing and in developmental dysplasia of the hip as a guide to operative treatment. In adult hips, arthrography and aspiration are useful techniques for demonstration of prosthetic implant loosening and infection. Aspiration of the hip joint and culture of aspirated fluid helps to diagnose septic arthritis. Anesthetic hip arthrography helps to distinguish between pain originating from the hip and radicular pain from the spine. Iliopsoas bursography may be used to diagnose bursal enlargement and its cause.

Adult↗