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Biomedical subjects

H Imhof

Publications and source records attributed to H Imhof.

293 records · Page 17Linked to original sources
PubMedDate not supplied

MRI of unfused lumbar segments after spondylodesis.

PURPOSE: Our goal was to find a causal relation between disk degeneration in nonfused lumbar segments, back pain, and the angle of scoliotic curves 21-30 years after dorsal spondylodesis. METHOD: Thirty-two patients with scoliosis had been treated by dorsal spondylodesis 21-30 years prior to this study (mean 25.2 +/- 2.4 years). With use of MRI, signs of disk degeneration in the nonfused lumbar segments (n = 131, mean 4.1 +/- 1.4) were evaluated. Back pain evaluation was performed using the Oswestry disability score. On plain X-ray films, the angle of scoliotic curves was measured (Cobb technique). Percentage and absolute number of degenerated disks were compared to the fusion level (number of unfused caudal segments), the Oswestry score, and the Cobb angle. RESULTS: Disk degeneration was present in 20 of 32 patients (62.5%) and in 37 of 131 unfused lumbar segments (28.2%). Of eight patients (24.2%), seven had moderate back pain and one severe back pain. The mean lumbar scoliotic curve was 44.4 +/- 24.9 degrees. No statistically significant correlation was found between patients with disk degeneration and fusion level, amount of back pain, or lumbar scoliotic angle (p < 0.05). CONCLUSION: A lack of correlation between disk degeneration in unfused lumbar segments and other parameters like fusion level, back pain, and scoliotic angle can be assessed in the long-term follow-up of multisegment fusion of scoliotic curves.

Adolescent↗
PubMedDate not supplied

MRI versus lateral stress radiography in acute lateral ankle ligament injuries.

PURPOSE: Our goal was to compare the abilities of MRI and stress radiography to detect the extent of recent lateral ankle ligament inversion injuries. METHOD: In this prospective study, 60 athletically active patients (aged 18-45 years) with recent inversion trauma (< or = 7 days) underwent stress radiography and MRI. In 15 patients, the MR findings were reviewed at surgery. Patients were divided into three groups according to severity of ligament injury on MRI (no, one, or two to three ligament tears). Based on bilateral stress radiography, patients were classified into three groups according to the differential degree of talar tilt (< or = 5, 6-14, or > or = 15 degrees) and compared with patients from the MR groups. RESULTS: Surgery showed MRI to have 74% sensitivity and 100% specificity in the evaluation of complete lateral ankle ligament tears. Agreement between MR and stress radiography groups for the severity of recent lateral ankle ligament tears was poor (kappa = 0.030). CONCLUSION: MRI should be performed in young, athletically active patients if surgical intervention is contemplated, especially at 6-14 degrees talar tilt on stress radiography, since stress radiography tends to over- and underestimate the severity of lateral ligament trauma.

Acute Disease↗
PubMedDate not supplied

Imaging articular cartilage defects with 3D fat-suppressed echo planar imaging: comparison with conventional 3D fat-suppressed gradient echo sequence and correlation with histology.

PURPOSE: Our goal was to shorten examination time in articular cartilage imaging by use of a recently developed 3D multishot echo planar imaging (EPI) sequence with fat suppression (FS). We performed comparisons with 3D FS GE sequence using histology as the standard of reference. METHOD: Twenty patients with severe gonarthrosis who were scheduled for total knee replacement underwent MRI prior to surgery. Hyaline cartilage was imaged with a 3D FS EPI and a 3D FS GE sequence. Signal intensities of articular structures were measured, and contrast-to-noise (C/N) ratios were calculated. Each knee was subdivided into 10 cartilage surfaces. From a total of 188 (3D EPI sequence) and 198 (3D GE sequence) cartilage surfaces, 73 and 79 histologic specimens could be obtained and analyzed. MR grading of cartilage lesions on both sequences was based on a five grade classification scheme and compared with histologic grading. RESULTS: The 3D FS EPI sequence provided a high C/N ratio between cartilage and subchondral bone similar to that of the 3D FS GE sequence. The C/N ratio between cartilage and effusion was significantly lower on the 3D EPI sequence due to higher signal intensity of fluid. MR grading of cartilage abnormalities using 3D FS EPI and 3D GE sequence correlated well with histologic grading. 3D FS EPI sequence agreed within one grade in 69 of 73 (94.5%) histologically proven cartilage lesions and 3D FS GE sequence agreed within one grade in 76 of 79 (96.2%) lesions. The gradings were identical in 38 of 73 (52.1%) and in 46 of 79 (58.3%) cases, respectively. The difference between the sensitivities was statistically not significant. CONCLUSION: The 3D FS EPI sequence is comparable with the 3D FS GE sequence in the noninvasive evaluation of advanced cartilage abnormalities but reduces scan time by a factor of 4.

Aged↗
PubMedDate not supplied

Dental MR tomography of the mandible.

Imaging of the jaw bones is routinely achieved by conventional X-ray tomography or CT. In this study a new imaging procedure (dental MR tomography) is introduced. Five subjects were positioned in the standard neck coil of a 1.0 T MR scanner, and T1- and T2-weighted imaging of the mandible was performed in the axial plane. After the examination, the data were reconstructed as panorama and cross-sectional images using a software package for dental imaging on a workstation. The neurovascular bundle within the mandibular canal (MC), its relation to the teeth, and the pulp chambers of the teeth were demonstrated excellently in all cases. Edema and reactive hypervascularization due to an inflammatory process were also well visible. Dental MR tomography could become a good alternative to X-ray-based imaging modalities of the jaw bones by additionally offering the advantage of directly imaging the neurovascular bundle within the MC. Furthermore, administration of contrast agent for differentiation of pathological alterations is possible.

Adult↗