[Assessment of geometric, biomechanical, and osteodensitometric properties of the ultradistal radius with peripheral quantitative computerized tomography in uremic patients with severe hyperparathyroidism].
BACKGROUND
Bone integrity and mineral status were studied with a noninvasive method in uremic patients with severe secondary hyperparathyroidism undergoing maintenance hemodialysis.


METHODS
Volumetric cortical and trabecular mineral density (cBMD, tBMD) and bone geometrical properties were evaluated in 16 patients (11 women and 5 men) candidate to parathyroidectomy. Peripheral quantitative Computed Tomography (pQCT) was used to make measurements at the distal radius of the nondominant forearm. Thirty-two age-matched healthy subjects were chosen as a control group. Cortical area (CA), cross-sectional area (Total A), cortical thickness (CThk) and stress strain index (SSI) were assessed as biomechanical parameters. Serum intact PTH levels were assessed with a radioimmunoassay method (IRMA).


RESULTS
Both cBMD and tBMD were decreased in all patients and the difference was more significant in women (p < .0004 and p < .009) than in the smaller group of men (p < .01 and p < .01). Serum PTH levels correlated negatively with cBMD (r = .52; p < .01), CThk (r = .51; p < .04), CA (r = .52; p < .03) and SSI (r = .54; p < .02), as well as tBMD (r = .34), though not significantly. Dialysis duration did not significantly correlate with cBMD (r = .33), tBMD (r = .20), CA (r = .31), CThk (r = .40) and SSI (r = .35). As for geometrical and biomechanical parameters, CA, CThk and SSI were significantly different in both male and female uremic patients in comparison with the relative controls. Bone quantitative analysis and three-dimensional (3D) representation with the paraboloid revolution model also demonstrated osteopenia.


CONCLUSIONS
pQCT shows significant cortical and trabecular osteopenia in uremic patients with severe secondary hyperparathyroidism. Osteopenia is associated with geometrical and mechanical impairment with consequently increased bone fragility and thus a higher risk of fracture. Prolonged PTH hyperexpression seems to be mainly associated with intracortical porosity and cortical-endosteal resorption. Bone quantitative analysis and 3D representation provide rapid automated information on the cortex mineral status.
Servizio di Medicina Nucleare, Cattedra e Scuola di Specializzazione in Medicina Nucleare, Ospedale San Paolo, Milano.
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Di Leo
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Tarolo
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Bestetti
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Tagliabue
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Del Sole
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Aliberti
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Ardemagni
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Gallieni
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Brancaccio
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Froehlich
D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D015519:Bone Density; D012080:Chronic Kidney Disease-Mineral and Bone Disorder / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011884:Radius / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology*; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed; D014511:Uremia / Q000150:complications*
Valutazione delle proprietà geometriche, biomeccaniche e osteodensitometriche del radio ultradistale mediante Tomografia Computerizzata quantitativa periferica nei pazienti uremici affetti da iperparatiroidismo grave.