Cortical Iron Accumulation as an Imaging Marker for Neurodegeneration in Clinical Cognitive Impairment Spectrum: A Quantitative Susceptibility Mapping Study

Objective@#Cortical iron deposition has recently been shown to occur in Alzheimer’s disease (AD). In this study, we aimed to evaluate how cortical gray matter iron, measured using quantitative susceptibility mapping (QSM), differs in the clinical cognitive impairment spectrum. @*Materials and Methods@#This retrospective study evaluated 73 participants (mean age ± standard deviation, 66.7 ± 7.6 years;52 females and 21 males) with normal cognition (NC), 158 patients with mild cognitive impairment (MCI), and 48 patients with AD dementia. The participants underwent brain magnetic resonance imaging using a three-dimensional multi-dynamic multi-echo sequence on a 3-T scanner. We employed a deep neural network (QSMnet+) and used automatic segmentation software based on FreeSurfer v6.0 to extract anatomical labels and volumes of interest in the cortex. We used analysis of covariance to investigate the differences in susceptibility among the clinical diagnostic groups in each brain region.Multivariable linear regression analysis was performed to study the association between susceptibility values and cognitive scores including the Mini-Mental State Examination (MMSE). @*Results@#Among the three groups, the frontal (P < 0.001), temporal (P = 0.004), parietal (P = 0.001), occipital (P < 0.001), and cingulate cortices (P < 0.001) showed a higher mean susceptibility in patients with MCI and AD than in NC subjects. In the combined MCI and AD group, the mean susceptibility in the cingulate cortex (β = -216.21, P = 0.019) and insular cortex (β = -276.65, P = 0.001) were significant independent predictors of MMSE scores after correcting for age, sex, education, regional volume, and APOE4 carrier status. @*Conclusion@#Iron deposition in the cortex, as measured by QSMnet+, was higher in patients with AD and MCI than in NC participants. Iron deposition in the cingulate and insular cortices may be an early imaging marker of cognitive impairment related neurodegeneration.

Revision Total Hip Arthroplasty Using Cementless Acetabular Cup / 대한정형외과학회잡지

PURPOSE: To evaluate the clinical and radiological results of revision total hip arthroplasty using cemetless acetabular cup and several kinds of morseled bone grafts. MATERIALS AND METHODS: We performed 20 cases of revision total hip arthroplasties between July 1993 and June 1996. Acetabular bone deficiency was classified as type I in 4 hips, type II in 13 hips, type III in 2 hips and type IV in one hip by AAOS classification. Autogenous bone graft was used in 10 cases, heterograft in 5 cases, allograft in 2 cases and a mixture with autografts and allografts in 2 cases. The average contact rate between cup and host bone was 33.5% in type I acetabular deficiency, 65.1% in type II, 50% in type III and 39% in type IV. RESULTS: The mean Harris hip score was 82.9 points at the last follow-up. Osseous union between host bone and graft bone occurred within 6 months in 14 cases. Radiological failure was noted in 8 cases at the last follow-up. Three cases were revised during the follow-up period. Five cases out of 7 cases in which the contact rate between acetabular cup and host bone was less than 50% were determined to be a radiologic failure. Only 2 cases of the 10 cases in which autogenous bone graft had failed grafts. The rate of complication was 7cases (35%). CONCLUSIONS: The usage of the hemispherical cementless acetabular cup with autogenous bone graft and increasing the contact rate between the acetabular cup and host bone could be a safe management method in revision total hip arthroplasty. We recomrnend avoiding the use of heterograft in cementless cup revision arthroplasty.

Anterior Spinal Instrumentation in Treatment of Spinal Tuberculosis / 대한정형외과학회잡지

OBJECTIVES: We performed anterior spinal fusion and instrumentation in treatment of spinal tuberculosis. The clinical results of this operation and metal-related complications were evaluated to determine the rationale of anterior instrumentation in active tuberculous lesion. METHODS: From July 1989 to February 1993, we treated twenty-one patients with spinal tuberculosis by radical resection of the tuberculous lesion and bone grafting, followed by anterior instrumentation using Zielke rod system. The changes in spinal deformity were measured from lateral spinal radiographs obtained preoperatively and postoperatively at 3 months, 6 months, 1 year, 2 years and final follow-up. The recurrence of infection and possible complications were also observed clinically and radiologically. RESULTS: The mean kyphotic angle was decreased preoperatively from 21 degrees to 16 degrees at final follow-up in patients with thoracolumbar tuberculous lesions. The mean deformity angle was corrected 7 degrees in thoracolumbar tuberculosis and 12 degrees in lumbar tuberculosis compared with the preoperative deformity angle. There was not any persistence or recurrence of infection possibly related to the instrumentation. All patients were allowed early ambulation with the aid of a light brace. CONCLUSION: The clinical and radiological results suggested that the anterior instrumentation seemed to be one of the rational approaches for providing immediate stability in treating severe spinal tuberculosis without any significant risk of persistence or recurrence of infection.

Intrapelvic Pseudocyst After Total Hip Arthroplasty: A Case Report / 대한정형외과학회잡지

Many uncemented acetabular components use transfixation screws to stabilize the acetabular component until ingrowth of bone occurs. But the use of transacetabular screw fixation in total hip arthroplasty could increase the incidence of intrapelvic complications including neurovascular injury, extrinsic compression and erosion of intrapelvic organs. Metal debris was attributed to corrosion or fretting between screw and metal shell may lead to pelvic osteolysis. A foreign body reaction to metal and polyethylene wear debris in a loose acetahular component eroded the medial wall of the acetabulum and produced an intrapelvic mass. We experienced a case of intrapelvic pseudocyst in a failed total hip arthroplasty. The cyst communicated with hip joint through the transacetabular fixation screw which was placed near the center of the acetahulum.