Quantitative Assessment of Tendon Healing by Using MR T2 Mapping in a Rabbit Achilles Tendon Transection Model Treated with Platelet-rich Plasma.

PURPOSE: To determine if magnetic resonance (MR) imaging T2 mapping can be used to quantify histologic tendon healing by using a rabbit Achilles tendon transection model treated with platelet-rich plasma (PRP). MATERIALS AND METHODS: Experiments were approved by the Institutional Animal Care and Use Committee. The Achilles tendons of 24 New Zealand white rabbits (48 limbs) were surgically transected, and PRP (in the test group) or saline (in the control group) was injected into the transection site. The rabbits were sacrificed 2, 4, 8, and 12 weeks after surgery. Thereafter, T2 mapping and histologic evaluations were performed by using the Bonar scale. A mixed-model multivariate analysis of variance was used to test the effects of time and PRP treatment on the T2 value and Bonar grade, respectively. The correlation between the T2 value and Bonar grade was also assessed by using the Spearman correlation coefficient. RESULTS: The Bonar scale values decreased in both groups during tendon healing. The T2 value also shortened over time (P < .001 for both groups). The T2 values were positively correlated with the Bonar grade (ρ = 0.78, P < .001). Both the T2 value and Bonar scale value were lower in the PRP group than in the control group at 4, 8, and 12 weeks; however, there was no significant effect of PRP treatment on the T2 value or Bonar grade. CONCLUSION: The T2 value changes reflected histologic tendon healing. While T2 and Bonar grade were lower at all time points in tendons treated with PRP, there was no significant difference between the treatment and control tendons.

Assessment of renal shape of horseshoe kidney with multidetector row CT in adult patients: relationship between urolithiasis and renal isthmus.

OBJECTIVE: The aim of this study was to evaluate the relationship between urolithiasis and characteristics of renal shape in adult patients with horseshoe kidney (HSK) diagnosed on multidetector row computed tomography (MDCT). METHODS: We evaluated 36 patients with HSK and urolithiasis (Group A) and 70 patients with HSK without urolithiasis (Group B) whose disease was diagnosed on non-contrast MDCT. Two radiologists measured minimum width of the renal isthmus and maximum length of the renal pelvis and evaluated coexisting neoplastic diseases on axial computed tomographic (CT) images with 5-mm reconstruction, and we compared those measurements between the Groups A and B. RESULTS: The overall mean maximum length of the renal pelvis, 12.7±9.2 mm, did not differ significantly between the 2 groups. Minimum isthmus width was larger in patients with HSK and urolithiasis (11.0±5.6 mm), than those without urolithiasis (9.5±5.1 mm). No patient in either groups had a urological renal tumor. CONCLUSIONS: Patients of HSK might have tendency of a high incidence of stone formation. Because urolithiasis is a risk factor for tumors of the renal pelvis, monitoring of patients with HSK requires careful attention to isthmus width on CT images.