•We examined the difference in the distribution of the speed of motorcycles related to their styles.•The sport style motorcycles have the most significant impact on the speed differentials between ...motorcycles and cars.•We found a significant relationship between the speed and the use of the motorcycles registration plates.•We concluded that the style of motorcycle (sport or not) and possession of registration plates can be used as a traffic safety indicator for motorcyclists.
This report examines the difference in the distribution of the speeds of different motorcycle styles and the difference in the distribution of speeds of particular motorcycle styles and cars. The relationship between the speed of motorcycles that possess and those that do not possess vehicle registration plates was also explored. The speed was measured at six different locations on main roads in the city of Belgrade, Serbia. The study confirmed that, on average, motorcyclists drive faster than drivers of cars, but extreme speeding is recorded 2.3 times more often by motorcyclists than by car drivers. In this research, the styles of motorcycles were divided into three different groups according to their average speeds. The first group consists of sport motorcycles, which were faster than the other styles. The second group consists of scooter motorcycles, which were slower. The third group consists of conventional, touring, enduro, and chopper motorcycles with speeds that were statistically not significantly different. According to the differences of the mean speed of motorcyclists who use and do not use vehicle registration plates, the use of the registration plates can be considered a significant indicator of traffic safety. By classifying motorcycles in the three different groups, the issue of “generalizing” motorcyclists as a unique group is avoided and can be taken into consideration for future studies of motorcyclist safety.
Objective
The effects of different therapies on enthesitis/osteitis in active ankylosing spondylitis (AS) were evaluated by magnetic resonance imaging (MRI). The aim was to assess the role of ...quantitative MRI in the evaluation of AS treatment efficacy.
Materials and methods
Thirty patients with active spondylitis or bilateral sacroilitis were selected and followed up for 1 year. Ten of the patients were treated only with non-steroidal anti-inflammatory drugs, 10 patients additionally received at baseline an intravenous pulse of glucocorticoids and 10 patients were treated with regular infusions of infliximab. Disease activity was measured according to clinical instruments and laboratory tests. For each patient, one selected inflamed lesion was followed from baseline through control visits quantitatively by diffusion-weighted imaging (DWI) measuring the apparent diffusion coefficient (ADC) and by dynamic contrast-enhanced imaging (DCEI) with evaluation of the enhancement factor (f
enh
) and enhancement gradient (g
enh
).
Results
Clinical and quantitative MRI parameters diminished significantly with regression of the inflammatory activity. The improvement in AS was most pronounced in patients treated with infliximab; after 12 months the ADC diminished from an average of 1.31 to 0.88 × 10
−3
mm
2
/s, f
enh
from 1.85 to 0.60, and g
enh
from 3.09 to 1.40 %/s.
Conclusion
Diffusion-weighted imaging and DCEI were shown to be effective in quantifying changes in inflammation in skeletal lesions during the treatment of AS, and could therefore be convenient for assessing treatment efficacy. To the best of our knowledge this is the first time DWI was used to evaluate the activity of skeletal inflammation in rheumatic diseases such as AS.
We present a case of osteosarcoma arising in an osteochondroma of the right fibula in a 30-year-old woman. The available radiographic studies of the lesion were not suggestive of malignant ...transformation. The lesion and underlying bone were excised. Histologic examination showed a conventional high-grade osteoblastic osteosarcoma that focally eroded the fibrocartilaginous cap. The patient received postoperative chemotherapy and shows no evidence of disease 27 months following operation. The occurrence of osteosarcoma in an osteochondroma is an extremely rare event, and only a few cases are on record in the literature.
Objective
The aim of the study was to evaluate the feasibility of two quantitative MRI methods: diffusion weighted imaging (DWI) and dynamic contrast enhanced imaging (DCEI), for follow-up assessment ...of the tibial tunnel after reconstruction of the anterior cruciate ligament (ACL).
Matherials and methods
Twenty-three patients were examined by MRI at 1 and 6 months following ACL reconstruction. DWI and DCEI were utilized for evaluating the region of interest (ROI) within the proximal part of the tibial tunnel. From the resulting apparent diffusion coefficient (ADC) maps, ADC values were calculated. DCEI data were used to extract the enhancement factor (f
enh
) and the enhancement gradient (g
enh
) for the same ROI.
Results
Calculated ADC as well as the f
enh
and g
enh
had diminished to a statistically significant extent by 6 months after ACL reconstruction. The average ADC value diminished from 1.48 (10
−3
mm
2
/s) at 1 month to 1.30 (10
−3
mm
2
/s) at 6 months after reconstruction. The average f
enh
value decreased from 1.21 at 1 month to 0.50 at 6 months and the average g
enh
value decreased from 2.01%/s to 1.15%/s at 6 months, respectively.
Conclusion
The study proved feasibility of DWI and DCEI for quantitative assessment of the tibial tunnel at 1 and 6 months after ACL reconstruction. Both methods have the potential for use as an additional tool in the evaluation of new methods of ACL reconstruction. To our knowledge, this is the first time quantitative MRI has been used in the follow-up to the ACL graft healing process.
Destructive and reconstructive processes at the reactive interface in femoral head osteonecrosis (FHO) are not well defined or predictable. The objectives of our study were to analyze scintigraphic ...characteristics of the reactive interface in the early stages of FHO and to assess the prognostic value of the reactive interface on scintigraphy (SC).
Thirty-six hips in 27 patients (21 men, 6 women; mean age 41 years, range 20 64 years) with a final diagnosis of radiographic stage 1 (4 hips) or stage 2 FHO (32 hips) were evaluated by planar and pinhole SC. Tracer uptake at the reactive interface on pinhole SC was assessed visually. Three categories were formed: normal, moderately increased, and highly increased activities. The time to head collapse was observed.
Tracer uptake at the reactive interface was more frequently increased in hips with stage 2 of the disease than in those with stage 1. In hips with the same stage of the disease, different activities were detected stage 1 FHO: moderately increased in 1 of 4 (25%) and highly increased in 1 of 4 (25%0) hips; stage 2 FHO: moderately increased in 8 of 32 hips (25%) and highly increased in 20 of 32 (631%/) hips. Femoral heads with highly increased activity at the reactive interface collapsed more frequently and earlier: 13/15 conservatively treated hips in stage 2 collapsed in 1-6 months, whereas no hips with normal uptake at the reactive interface collapsed in 12 months follow-up and only one of six hips with moderately increased activity collapsed after 11.5 months (P < 0.05).
Our results indicate that the tracer uptake at the reactive interface can be different in the same stage of FHO. High tracer uptake at the reactive interface in the early phases of FHO seems to be a bad prognostic sign for femoral head collapse.
Abstract The aim of the study was a comparison of 2 novel macromolecular contrast agents, Gadomer-17 and Polylysine-Gd-DTPA, with commercially available Gd-DTPA in determining the quality of tumor ...microvasculature by dynamic contrast enhanced MRI. Three groups of 5 mice with SA-1 tumors were studied. To each group of animals one contrast agent was administered; i.e. the first group got Gd-DTPA, the second group Gadomer-17 and the third group Polylysine-Gd-DTPA. To perform dynamic contrast enhanced MRI a standard keyhole approach was used by which consecutive signal intensity change due to contrast agent accumulation in the tumor was measured. From the obtained data, tissue permeability surface area product PS and fractional blood volume BV were calculated on a pixel-by-pixel basis. PS and BV values were calculated for each contrast agent. Based on the values, contrast agents were classified according to their performance in characterizing tumor microvasculature. Results of our study suggest that Gadomer-17 and Polylysine-Gd-DTPA are significantly superior to Gd-DTPA in characterizing tumor microvasculature.
Vertebral infection Jevtic, Vladimir
European radiology,
03/2004, Letnik:
14 Suppl 3
Journal Article
Recenzirano
Vertebral infection represents 2-4% of all cases of osteomyelitis. An increase in the incidence of pyogenic as well as granulomatous spondylitis has been noticed. Early radiological diagnosis is of ...great importance for prompt treatment and prevention of clinically significant consequences which include neural compromise and late spinal deformities. The most frequent causative pyogenic micro-organisms are gram-negative bacteria especially Staphylococcus aureus. An important form of nonpyogenic granulomatous infection is tuberculous spondylitis which represents the most common form of extrapulmonary tuberculosis. The routes of spinal infection include hematogenous spread, postoperative infections, direct implantation during spinal punctures and spread from a contiguous focus. The role of imaging is an early diagnosis, evaluation of extent of infection with special regard to potential neural compromise, differential diagnosis, guidance of diagnostic biopsy, planning of eventual operative procedures and assessment of therapeutic response. Imaging modalities include bone scintigraphy, radiography, CT and MRI. In practice, usually a combination of a sensitive and a specific method is utilised. The only imaging modality which combines high sensitivity with satisfactory specificity is MRI. This is the reason that MRI frequently has become the first imaging modality in clinically suspect spinal infection. The MRI is the method of choice for direct demonstration of extension of infection, especially of eventual epidural abscess or phlegmon and consecutive neural compression. Using MRI monitoring of therapeutic efficiency is possible.
PDF
