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Biomedical subjects

E M Akkerman

Publications and source records attributed to E M Akkerman.

5 recordsLinked to original sources
PubMed2006

Sequential MR imaging changes in nonketotic hyperglycinemia.

Serial diffusion-weighted (DWI) and diffusion tensor imaging (DTI) were performed in a patient with neonatal onset nonketotic hyperglycinemia (NKH). At 3 weeks areas that are normally myelinated at this time showed increased T2-signal intensity and restricted diffusion, consistent with vacuolating myelinopathy. At 3 months, these areas had increased in the topographic pattern of normal myelination, whereas fractional anisotropy was compatible with axonal sparing. At 17 months, diffusion restriction had disappeared, likely because of coalescence of myelin vacuoles. A decrease of fractional anisotropy was observed in the previously myelinated areas indicative of axonal loss. We conclude that DWI and DTI can be used to identify and characterize white matter tract abnormalities in patients with NKH.

Brain↗
PubMed2001

MRI in clinically asymptomatic neuropathic leprosy feet: a baseline study.

This study was undertaken to analyze the magnetic resonance imaging (MRI) findings in the clinically asymptomatic neuropathic feet of leprosy patients. Since in the literature no MRI data are available concerning the asymptomatic neuropathic foot in leprosy, the interpretation of MRI examinations in clinically suspected neuropathic feet in leprosy is difficult. We examined 10 adult leprosy patients with clinically asymptomatic neuropathic feet. Inclusion criteria were a normal or near normal neuropathic foot, without signs of inflammation. All patients underwent an MRI protocol with the inclusion of two-point Dixon chemical shift imaging as fat suppression sequence. We found MRI changes in almost all patients. The most striking were the changes located in the region of the first metacarpophalangeal (MTP) joint. These changes ranged from degradation and interruption of the subcutaneous fat to effusion/synovitis in the first MTP joint. This study reveals significant MRI changes in clinically asymptomatic neuropathic feet in patients with leprosy. These changes may relate to the development of ulcerations. MRI may play an important role in detecting feet at risk and may influence clinical decision making.

Adult↗
PubMed1999

Uniform fat suppression in hands and feet through the use of two-point Dixon chemical shift MR imaging.

PURPOSE: To assess the potential of two-point Dixon chemical shift magnetic resonance imaging to achieve uniform fat suppression in the distal parts of the extremities. MATERIALS AND METHODS: Two-point Dixon chemical shift imaging was performed in 31 consecutive patients clinically suspected to have bone marrow disease. In some patients, Dixon studies were performed before and after the intravenous administration of gadopentetate dimeglumine, and in some patients follow-up examinations were performed, for a total of 64 studies. Areas of interest were the hand, wrist, foot, ankle, and lower leg. There was a special interest in the neuropathic foot and osteomyelitis. The uniformity of fat suppression in the entire field of view, the frequency of displacement artifacts, and the applicability of the technique in routine patient treatment were evaluated. RESULTS: In 64 (100%) Dixon studies, uniform fat suppression was achieved. In 59 (92%) studies, there were no displacement artifacts. In five (8%) studies, displacement artifacts occurred; however, in only one (2%) study did they severely hamper the reading. Thus, in 63 (98%) studies, adequate diagnostic quality was obtained. CONCLUSION: Two-point Dixon chemical shift imaging is a good technique for achieving uniform fat suppression in the distal parts of the extremities. Because the frequency of displacement artifacts is low, the technique is applicable in a routine clinical setting.

Adipose Tissue↗
PubMedDate not supplied

Dixon quantitative chemical shift MRI for bone marrow evaluation in the lumbar spine: a reproducibility study in healthy volunteers.

PURPOSE: The purpose of this work was to explore the reproducibility of fat-fraction measurements using Dixon quantitative chemical shift imaging (QCSI) in the lumbar spine (L3, L4, and L5) of healthy volunteers. METHOD: Sixteen healthy volunteers were examined at 1.5 T two times to obtain a repeated measurement in the same slice and a third time in three parallel slices. Single slice, two point Dixon SE (TR/TE 2,500/22.3) sequences were used, from which fat-fraction images were calculated. The fat-fraction results are presented as averages over regions of interest, which were derived from the contours of the vertebrae. Reproducibility measures related to repeated measurements on different days, slice position, and contour drawing were calculated. RESULTS: The mean fat fraction was 0.37 (SD 0.08). The SD due to repeated measurement was small (sigmaR = 0.013-0.032), almost all of which can be explained by slice-(re)-positioning errors. CONCLUSION: When used to evaluate the same person longitudinally in time, Dixon QCSI fat-fraction measurement has an excellent reproducibility. It is a powerful noninvasive tool in the evaluation of bone marrow composition.

Adipose Tissue↗