Focal liver lesions: whether a standard dose (0.05 mmol/kg) gadobenate dimeglumine can provide the same diagnostic data as the 0.1 mmol/kg dose

Objective

Gadobenate dimeglumine (Gd-BOPTA) is a liver-specific contrast agent also showing a distribution in the extracellular compartment which is recommended to be used at standard dose (0.05 mmol/kg) in magnetic resonance imaging (MRI) of liver lesions. However, its use at 0.1 mmol/kg is gradually increasing in recent clinical practice. Which dose should we use in routine MRI of liver lesions from now on? This study investigated the efficacy of Gd-BOPTA at a standard dose versus 0.1 mmol/kg dose in demonstrating diagnostic data in MRI of focal liver lesions.

Materials and methods

The study included 47 patients with focal liver lesions. Twenty-two patients received standard dose and 25 patients received 0.1 mmol/kg dose Gd-BOPTA intravenously. MRI of both groups was carried out with T1-A FLASH-2D and T2-A TURBO spin echo before contrast injection and T1-A FLASH-2D sequences in dynamic and late phase (90th minute) after the contrast injection. The lesion conspicuity for each image was evaluated qualitatively. Liver signal to noise ratio (SNR), absolute lesion-liver contrast to noise ratio (CNR), mean lesion-liver CNR and contrast enhancement rate of the liver obtained from both groups were compared quantitatively.

Results

While liver contrast enhancement rate in the group receiving standard dose Gd-BOPTA were 41% ± 42 in the arterial phase, 66% ± 58 in the portal phase, 45% ± 45 in the venous phase and 42% ± 88 in the late phase, these values were 43% ± 59, 86% ± 73, 63% ± 75 and 61% ± 105, respectively, in the group receiving the dose of 0.1 mmol/kg. There were no statistically significant differences between the means of both groups. While the absolute lesion-liver CNR values were 18 ± 15 precontrast, 22 ± 18 in the arterial phase, 19 ± 17 in the portal phase, 15 ± 10 in the venous phase and 24 ± 26 in the late phase in the group receiving the standard dose Gd-BOPTA, these values were 13 ± 11, 18 ± 15, 15 ± 15, 13 ± 13 and 19 ± 21, respectively, in the group receiving the 0.1 mmol/kg dose. There were no statistically significant differences between the means of both groups (p > 0.05). However, when the mean lesion-liver CNR values were compared, there was statistically significant difference between each arterial and portal phases of metastases in both groups (p < 0.05). There was no statistical difference found in other lesions. When lesion conspicuity scores were compared, there were no significant differences between the two groups.

Conclusion

In liver lesions, similar diagnostic data are obtained in dynamic and late phase MRI with either standard dose Gd-BOPTA or with a dose of 0.1 mmol/kg. Because there was a difference in only metastases in both groups, in oncological patients who are being investigated for liver metastasis, it is expedient to use a dose of 0.1 mmol/kg.     

Angiotensin I Converting Enzyme Activity in Uranyl Nitrate Induced Acute Renal Failure in Rats

Although complete blood count is routinely ordered in most upper urinary tract infections (UTI), and information regarding the patient's platelet indices is made available without added cost, the relationship between platelet count and mean platelet volume (MPV) and specific platelet responses to different infectious agents has not been extensively characterized in UTI. The objectives of this study were to examine platelet counts and platelet indices in children with culture-proven upper UTI to determine if there are organism-specific platelet responses. A retrospective analysis of data from all pediatric urine samples processed at Fatih University Medical School microbiology laboratory was undertaken for a period of two years (January 1, 2005, to December 31, 2006). Of the 200 patients with positive urine cultures, 146 (73%) were infected with gram-negative bacteria and 54 (27%) grew gram-positive bacteria. The platelet count during the episode of upper UTI and the incidence of thrombocytosis was significantly higher with the gram-positive infections than with the gram-negative infections or controls (p < 0.05). A statistically significant higher MPV was detected in the subjects with upper UTI (p < 0.05). Also, our data showed a statistically significant increase in MPV with gram-positive infections compared with the other groups (p < 0.05). In conclusion, based on the importance of the hemostatic component in the pathophysiology of infections, our findings of platelet count and MPV and predictivity of the type of the organism would suggest the usefulness of the routine measurements in children with upper UTI.     

Percutaneous Balloon Angioplasty of Renovascular Hypertension in Pediatric Cases

Purpose : To investigate effectiveness of percutaneous transluminal renal angioplasty (PTRA) in treatment of renal artery stenoses due to Takayasu arteritis (TA), fibromuscular dysplasia (FMD) and neurofibromatosis (NF). Materials-methods : Between December 1991-October 2006, 20 pediatric cases (age range 3–18 years, meanly 12.5 year) with at least 60% stenoses were underwent PTRA. Main presenting symptom was hypertension. The aetiologies were TA in 12, and FMD in 5, NF in three cases.

Results : Totally, 46 procedures were performed on 35 stenotic segments of 20 cases. A technically good result was obtained in 21/24 arteries of TA patients, 7/7 arteries of FMD patients, and 1/3 arteries of NF1 patients. Clinical follow-up for a mean of 55.7 months revealed 100% success in all cases. Delayed clinical response was seen in two cases with Nf1. Restenosis was detected 5/12 of TA patients, 1/5 of FMD patients and 1/3 NF1 patients.

Conclusion : PTRA can be safely performed resulting in excellent angiographic and clinical results. It should be first choice in renal artery stenosis in pediatric age when medical treatment fails to control renovascular hypertension or renal function is decreasing although initial results might be not encouraging in NF1.     

3D-printed poly(lactic acid) scaffolds for trabecular bone repair and regeneration: scaffold and native bone characterization

Purpose: Study objectives were set to (i) fabricate 3D-printed scaffolds/grafts with varying pore sizes, (ii) characterize surface and mechanical properties of scaffolds, (iii) characterize biomechanical properties of bovine trabecular bone, and (iv) evaluate attachment and proliferation of human bone marrow mesenchymal stem cells on 3D-printed scaffolds.

Materials and Methods: Poly(lactic acid) scaffolds were fabricated using 3D-printing technology, and characterized in terms of their surface as well as compressive mechanical properties. Trabecular bone specimens were obtained from bovine and characterized biomechanically under compression. Human bone marrow mesenchymal stem cells were seeded on the scaffolds, and their attachment capacity and proliferation were evaluated.

Results: Contact angles and compressive moduli of scaffolds decreased with increasing pore dimensions of 0.5 mm, 1.0 mm, and 1.25 mm. Biomechanical characterization of trabecular bone yielded higher modulus values as compared to scaffolds with all pore sizes studied. Human bone marrow mesenchymal stem cells attached to the surfaces of all scaffolds yet proliferated more on scaffolds with 1.25 mm pore size.

Conclusions: Collectively, given the similarity between 3D-printed scaffolds and native bone in terms of pore size, porosity, and appropriate mechanical properties of scaffolds, the 3D-printed poly(lactic acid) (PLA) scaffolds of this study appear as candidate substitutes for bone repair and regeneration.     

Implant-assisted dental rehabilitation of a patient with maxillary rhabdomyosarcoma

ABSTRACT: Rhabdomyosarcoma is a malignant, soft tissue neoplasm consisting of cells derived from the primitive mesenchyme that exhibit a profound tendency to undergo myogenesis. Multimodality therapy for tumors in the head and neck regions has a significant effect on maxillofacial skeletal growth, dental development, and the whole ecologic system of the oral cavity.Here we aimed to discuss the influence of head-neck cancer therapy in pediatric patients with long-term follow-up and present a case with implant-assisted dental rehabilitation and also functional and aesthetic outcomes.     

Evaluation of microtensile bond strength of different fissure sealants to bovine enamel

Background: The aim of this study was to evaluate the microtensile bond strength (μTBS) of a new fissure sealant and compare it with conventional sealants which are applied to enamel alone, and also with self‐etch and etch‐and‐rinse adhesives. Methods: Enamel specimens were prepared and randomly distributed into three groups according to fissure sealant (Aegis, Helioseal F, Helioseal Clear). Each group was then subdivided according to adhesive system (Clearfil S3, Single Bond, no adhesive). A universal testing machine was used to measure μTBS, and data were analysed using one‐way ANOVA and Tukey’s tests. Results: μTBS values for all Aegis subgroups were significantly lower than for comparable Helioseal F and Helioseal Clear subgroups (p < 0.05). No differences were observed in μTBS of Helioseal F and Helioseal Clear (p > 0.05). In the Helioseal Clear group, μTBS values for Single Bond were significantly higher than for Clearfil S3 (p < 0.05). However, no significant differences were found between the μTBS values of the adhesive subgroups in the Aegis or Helioseal F groups (p > 0.05). Conclusions: Sealant μTBS values may be affected by material content. The addition of an adhesive may improve μTBS values of sealant to enamel.