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Introduction: Bone mineral density (BMD) is reduced in patients with human immunodeficiency virus (HIV) infection. Trabecular bone score (TBS) is an additional feature calculated by dual-energy X ray absorption (DXA) that measures texture inhomogeneity at lumbar spine level, providing an index of bone microarchitecture. However, its clinical value still needs to be fully addressed. Aims of the study were to assess BMD and TBS in a cohort of patients with HIV compared to a population of healthy subjects and to investigate the prognostic value of TBS in HIV infected patients. Method: Bone health was assessed by DXA in 165 patients with HIV infection (120 men, mean age 40 ± 7 years) and in 164 healthy subjects (53 male, mean age 37 ± 10 years). BMD was measured at level of lumbar spine (L1-L4), femoral neck and total hip. TBS was computed from the images of lumbar spine using machine proprietary software. Results: BMD at femoral neck level was similar in HIV infected patients and healthy subjects (p = 0.57), whereas BMD measured in total femur was lower in HIV infected patients compared to healthy subjects (p < 0.05). Although mean BMD in lumbar spine was similar between HIV infected patients and healthy subjects (p = 0.90), mean lumbar TBS was lower in patients with HIV infection compared to healthy subjects (p < 0.05). Age, sex and HIV infection resulted independent predictors of reduced TBS. In HIV infected patients age, sex and protease inhibitor duration resulted independent predictors of reduced TBS. TBS was a significant predictor of vertebral fractures during follow-up (p < 0.05). Conclusion: Patients with HIV infection have a significant reduction of TBS, a texture parameter related to bone microarchitecture that may provide skeletal information that is not captured from the standard BMD measurement.
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We assessed the outcome of administration of empiric radioactive iodine (RAI) therapy to patients with differentiated thyroid cancer (DTC), in a propensity-score-matched cohort of patients with biochemical incomplete response (BIR) and without evidence of structural disease. We retrospectively evaluated 820 DTC patients without distant metastases, who underwent total thyroidectomy followed by RAI therapy, with available BIR at 12 months and follow-up evaluations. The patients were categorized according to the administration of empiric therapy (ET). To account for differences between patients with (n = 119) and without (n = 701) ET, a propensity-score-matched cohort of 119 ET and 119 no-ET patients was created. The need for additional therapy and the occurrence of structural disease were considered as end-points. During a median follow-up of 53 months (range 3-285), 57 events occurred (24% cumulative event rate). The rate of events was significantly higher in the no-ET compared to the ET patients (30% vs. 18% p < 0.001). The multivariate Cox analysis identified age (p < 0.01), pre-therapy Tg (p < 0.05) and empiric RAI therapy (p < 0.01) as predictors of outcome. The Kaplan-Meier analysis found that progression-free survival was lower in no-ET patients compared to the ET group (p < 0.01). In patients with DTC treated with surgery and RAI, and with biochemical incomplete response at the 12-month evaluation, their prognosis seemed to be affected by Tg values and the empiric treatment. The identification of candidates for this approach may improve prognosis.
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Individualized dosimetry in nuclear medicine is currently at least advisable in order to obtain the best risk-benefit balance in terms of the maximal dose to lesions and under-threshold doses to radiosensitive organs. This article aims to propose a procedure for fast dosimetric calculations based on planar whole-body scintigraphy (WBS) images and developed to be employed in everyday clinical practice. METHODS: For simplicity and legacy reasons, the method is based on planar imaging dosimetry, complemented with some assumptions on the radiopharmaceutical kinetics empirically derived from single-photon emission tomography/computed tomography (SPECT/CT) image analysis. The idea is to exploit a rough estimate of the time-integrated activity as has been suggested for SPECT/CT dosimetry but using planar images. The resulting further reduction in dose estimation accuracy is moderated by the use of a high-precision Monte-Carlo S-factor, such as those available within the OpenDose project. RESULTS: We moved the problem of individualized dosimetry to a transformed space where comparing doses was imparted to the ICRP Average Male/Female computational phantom, resulting from an activity distribution related to patient's pharmaceutical uptake. This is a fast method for the personalized dosimetric evaluation of radionuclide therapy, bearing in mind that the resulting doses are meaningful in comparison with thresholds calculated in the same framework. CONCLUSION: The simplified scheme proposed here can help the community, or even the single physician, establish a quantitative guide-for-the-eye approach to individualized dosimetry.
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Intramedullary spinal cord metastases (ISCM) are uncommon metastases of the spinal cord. Magnetic resonance (MR) plays an important role in surgical planning when ISCM is suspected in the differential diagnosis. The incidence of ISCM is expected to increase due to the longer survival of cancer patients as well as the widespread use of MR in the diagnosis of neurological syndromes. The management of these patients is controversial because of the multiple clinical presentations and lack of controlled studies on the efficacy of different therapeutic approaches. Increased awareness of this rare entity may lead to an earlier diagnosis with novel imaging approaches at a stage when neurological deficits are reversible. A case of ISCM in a 49-year-old patient with differentiated thyroid cancer is reported.