Feasibility of dual-phase 99mTc-MDP SPECT/CT imaging in rheumatoid arthritis evaluation.

BACKGROUND: To prospectively demonstrate the feasibility of performing dual-phase SPECT/CT for the assessment of the small joints of the hands of rheumatoid arthritis (RA) patients, and to evaluate the reliability of the quantitative and qualitative measures derived from the resulting images. METHODS: A SPECT/CT imaging protocol was developed in this pilot study to scan both hands simultaneously in participants with RA, in two phases of 99mTc-MDP radiotracer uptake, namely the soft-tissue blood pool phase (within 15 minutes after radiotracer injection) and osseous phase (after 3 hours). Joints were evaluated qualitatively (normal vs. abnormal uptake) and quantitatively [by measuring a newly developed metric, maximum corrected count ratio (MCCR)]. Qualitative and quantitative evaluations were repeated to assess reliability. RESULTS: Four participants completed seven studies (all four were imaged at baseline, and three of them at follow-up after 1-month of arthritis therapy). A total of 280 joints (20 per hand) were evaluated. The MCCR from soft-tissue phase scans was significantly higher for clinically abnormal joints compared to clinically normal ones; P<0.001, however the MCCR from the osseous phase scans were not different between the two joint groups. Intraclass Correlation Coefficient (ICC) for MCCR was excellent [0.9789, 95% confidence interval (CI): 0.9734-0.9833]. Intra-observer agreement for qualitative SPECT findings was substantial for both the soft-tissue phase (kappa =0.78, 95% CI: 0.72-0.83) and osseous-phase (kappa =0.70, 95% CI: 0.64-0.76) scans. CONCLUSIONS: Extracting reliable quantitative and qualitative measures from dual-phase 99mTc-MDP SPECT/CT hand scans is feasible in RA patients. SPECT/CT may provide a unique means for assessing both synovitis and osseous involvement in RA joints using the same radiotracer injection.

Nasal Dorsal Augmentation with Freeze-Dried Allograft Bone: 10-Year Comprehensive Review.

BACKGROUND: The aim of this study was to evaluate freeze-dried cortical allograft bone for nasal dorsal augmentation. The 42-month report on 18 patients was published in 2009 in Plastic and Reconstructive Surgery with 89 percent success at level II evidence, and this article is the 10-year comprehensive review of 62 patients. METHODS: All grafts met standards recommended by the American Association of Tissue Banks, the U.S. Food and Drug Administration, and the Centers for Disease Control and Prevention. Objective evaluation of the persistence of graft volume was obtained by cephalometric radiography, cone beam volumetric computed tomography, and computed tomography at up to 10 years. Vascularization and incorporation of new bone elements within the grafts were demonstrated by fluorine-18 sodium fluoride positron emission tomography at up to 10 years. Subjective estimation of graft volume persisting up to 10 years was obtained by patient response to a query conducted by an independent surveyor. RESULTS: The authors report objective proof of persistence of volume alone or combined with proof of neovascularization in 16 of 19 allografts. The authors report the patient's subjective opinion of volume persistence in 37 of 43 grafts. The dorsal augmentation was assessed overall to be successful in 85 percent of 62 patients evaluated between 1 and 10 years, with a mean of 4.7 years. CONCLUSIONS: Freeze-dried allograft bone is a safe and equal alternative for dorsal augmentation without donor-site morbidity. Further studies are needed to (1) confirm these findings for young patients needing long-term reconstruction, and (2) partially demineralize allograft bone to allow carving with a scalpel. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Early and Delayed 99mTc-MDP SPECT/CT Findings in Rheumatoid Arthritis and Osteoarthritis.

We report the case of a 74-year-old man with seropositive rheumatoid arthritis (RA) and radiographic osteoarthritis (OA) who underwent dual-phase high-resolution Tc-MDP SPECT/CT. Early radiotracer enhancement was noted in 2 RA joints of the right hand, both presenting with a ring-like uptake pattern around the joint, consistent with synovitis. Insignificant early enhancement was noted at the first carpometacarpal joint, despite presentation of CT features of OA. The delayed-phase enhancement patterns were distinct, showing asymmetry in RA joints, but a symmetric, joint-centered pattern for the OA joint.

Evaluation of penalty design in penalized maximum-likelihood image reconstruction for lesion detection.

Detecting cancerous lesions is a major clinical application in emission tomography. Previously, we developed a method to design a shift-variant quadratic penalty function in penalized maximum-likelihood (PML) image reconstruction to improve the lesion detectability. We used a multiview channelized Hotelling observer (mvCHO) to assess the lesion detectability in three-dimensional images and validated the penalty design using computer simulations. In this study, we evaluate the benefit of the proposed penalty function for lesion detection using real patient data and artificial lesions. A high-count real patient dataset with no identifiable tumor inside the field of view is used as the background data. A Na-22 point source is scanned in air at variable locations and the point source data are superimposed onto the patient data as artificial lesions after being attenuated by the patient body. Independent Poisson noise is introduced to the high-count sinograms to generate 200 pairs of lesion-present and lesion-absent datasets, each mimicking a 5-min scan. Lesion detectability is assessed using a mvCHO and a human observer two-alternative forced choice (2AFC) experiment. The results show improvements in lesion detection by the proposed method compared with the conventional first-order quadratic penalty function and a total variation (TV) edge-preserving penalty function.

Nasal dorsal augmentation with freeze-dried allograft bone.

BACKGROUND: Properly prepared freeze-dried bone has been used with impunity by orthopedic surgeons since 1992 without a single report of disease transmission. The aim of this study was to evaluate freeze-dried cortical allograft bone for nasal dorsal augmentation. METHODS: Freeze-dried human cortical bone was obtained from DCI Donor Services, Nashville, Tennessee. Standards recommended by the American Association of Tissue Banks, the U.S. Food and Drug Administration, and the Centers for Disease Control and Prevention were followed. Objective evaluation of the persistence of graft volume was obtained by cephalometric radiography. Vascularization and incorporation of new bone elements within the grafts were demonstrated by using fluorine-18 sodium fluoride positron emission tomographic/computed tomographic scanning. RESULTS: The average persistence of projection in 18 patients was 87 percent at 6 months. Thereafter, 10 patients showed 100 percent maintenance of projection at 12 to 36 months. Vascularization and incorporation of new bone elements within the grafts were demonstrated by using fluorine-18 sodium fluoride positron emission tomographic/computed tomographic scanning in four patients. CONCLUSIONS: The initial loss of 13 percent of projection is most likely attributable to resolution of early surgical edema. The authors postulate that there are two pathways based on whether the recipient bed allows vascular access to the graft. The revascularization or inductive pathway involves stem cell conversion to eventual osteoblasts. The scar bed barrier or noninductive pathway involves the preservation of the graft as an unchanged alloimplant. This report is the first of a series that will include a 5-year and a 10-year follow-up.