Artefacts induced by coiled intracranial aneurysms on 3.0-Tesla versus 1.5-Tesla MR angiography—An in vivo and in vitro study

Objective

To compare metal-induced artefacts from coiled intracranial aneurysms on 3.0-Tesla and 1.5-Tesla magnetic resonance angiography (MRA), since concerns persist on artefact enlargement at 3.0 Tesla.

Materials and methods

We scanned 19 patients (mean age 53; 16 women) with 20 saccular aneurysms treated with coils only, at 1.5 and 3.0 Tesla according to standard clinical 3D TOF-MRA protocols containing a shorter echo-time but weaker read-out gradient at 3.0 Tesla in addition to intra-arterial digital subtraction angiography (IA-DSA). Per modality two neuro-radiologists assessed the occlusion status, measured residual flow, and indicated whether coil artefacts disturbed this assessment on MRA. We assessed relative risks for disturbance by coil artefacts, weighted kappa's for agreement on occlusion levels, and we compared remnant sizes. For artefact measurements, a coil model was created and scanned with the same protocols followed by 2D MR scans with variation of echo-time and read-out gradient strength.

Results

Coil artefacts disturbed assessments less frequently at 3.0 Tesla than at 1.5 Tesla (RR: 0.3; 95%CI: 0.1–0.8). On 3.0-Tesla MRA, remnants were larger than on 1.5-Tesla MRA (difference: 0.7 mm; 95%CI: 0.3–1.1) and larger than on IA-DSA (difference: 1.0 mm; 95%CI: 0.6–1.5) with similar agreement on occlusion levels with IA-DSA for both field strengths (κ 0.53; 95%CI: 0.23–0.84 for 1.5-Tesla MRA and IA-DSA; κ 0.47; 95%CI: 0.19–0.76 for 3.0-Tesla MRA and IA-DSA). Coil model artefacts were smaller at 3.0 Tesla than at 1.5 Tesla. The echo-time influenced artefact size more than the read-out gradient.

Conclusions

Artefacts were not larger, but smaller at 3.0 Tesla because a shorter echo-time at 3.0 Tesla negated artefact enlargement. Despite smaller artefacts and larger remnants at 3.0 Tesla, occlusion levels were similar for both field strengths.     

开通闭塞冠状动脉策略的全球性研究 GUSTO—Ⅱb（亚组研究）

病人资料 3 289例因急性冠脉综合征而接受溶栓治疗的患者,2274例接受t－PA治疗,1015例接受链激酶治疗。     

The importance of injury as a cause of death in sub-Saharan Africa: results of a community-based study in Tanzania

This paper describes rates and causes of injury deaths among community members in three districts of the United Republic of Tanzania. A population-based study was carried out in two rural districts and one urban area in Tanzania. Deaths occurring in the study areas were monitored prospectively during a period of six years. Censuses were conducted annually in the rural areas and biannually in the urban area to determine the denominator populations. Cause-specific death rates and Years of Life Lost (YLL) due to injury were calculated for the three study areas. During a 6 year period (1992-1998), 5047 deaths were recorded in Dar es Salaam, 9339 in Hai District and 11 155 in Morogoro Rural District. Among all ages, deaths due to injuries accounted for 5% of all deaths in Dar es Salaam, 8% in Hai and 5% in Morogoro. The age-standardised injury death rates among men were approximately three times higher than among women in all study areas. Transport accidents were the commonest cause of mortality in all injury-related deaths in the three project areas, except for females in Hai District, where it ranked second after intentional self-harm. We conclude that injury deaths impose a considerable burden in Tanzania. Strategies should be strengthened in the prevention and control of avoidable premature deaths due to injuries.     

Bacterial cultures of the middle meatus and bronchoalveolar lavage in chronic rhinosinusitis

The role of bacteria in chronic rhinosinusitis (CRS) is still debated and their effect on the lower airways is less known. The aim of this study was to identify the individual bacterial species in CRS and to correlate these microbiological data with the clinical findings and associated bacterial cultures of the lower airways. This prospective study included 25 CRS patients scheduled for functional endoscopic sinus surgery. Preoperatively, pulmonary function and CT examinations were performed together with endoscopic and clinical assessment. Under aseptic conditions, with the patient under general anesthesia, 25 bronchoalveolar lavages (BALs) via the endotracheal tube and 50 endoscopically guided middle meatal specimens were obtained. All the specimens were examined for aerobic and anaerobic bacteria and correlated to the associated neutrophilic cellular changes. Positive bacterial cultures were obtained in 71% of the middle meatal specimens and 8% of the BAL specimens. Three subgroups of lower airway involvement were identified, i.e. asthma, small airway disease (SAD) and normal lower airways. In SAD only, there was a significant correlation between the cultured bacteria of the left (p = 0.04) and the right (p = 0.04) middle meatus and the presence of local neutrophilia. In asthma, middle meatal bacterial cultures correlated with nasal blockage (p = 0.04) and CT Lund-Mackay score (p = 0.04). CONCLUSION: Middle meatal cultures were frequently positive, mainly aerobic Gram-positive bacteria. In SAD, a mixed flora of Gram-positive aerobic bacteria and anaerobic bacteria was observed that correlated with neutrophilic inflammation. BAL cultures do not show infection or colonization of the lower airways, despite functional abnormalities in 60% of the patients.     

Multicystic dysplastic kidney: observations of contralateral disease in the fetal population

To evaluate multicystic dysplastic kidney (MDK) and associated contralateral renal abnormalities in the fetal population, 27 cases detected and followed in utero were reviewed retrospectively. The sonographic assessment included estimation of amniotic fluid volume and interval growth, evaluation for non-genitourinary anomalies, and postnatal follow-up study. Contralateral renal anomalies were detected in 41% of the fetuses and included obstruction of the ureteropelvic junction, renal agenesis, renal hypoplasia, and bilateral MDK. The incidences of these malformations were compared with results of earlier studies of MDK in the pediatric and adult populations. Lethal anomalies, such as bilateral MDK and MDK associated with contralateral agenesis, are common (19% and 11%, respectively) in the fetal population; obstruction of the contralateral ureteropelvic junction, a nonlethal anomaly, was seen less commonly (7%). Perinatal death from lethal abnormalities may spuriously raise the incidence of nonlethal contralateral abnormalities in the pediatric and adult populations. Contralateral mild fetal pyelectasis, found in 15% of fetuses with MDK, was not clinically significant.     

Resolving duodenal-jejunal hematoma in abused children

Acute intramural duodenal-jejunal hematoma is a classical finding in the battered child syndrome. The radiographic findings of a large obstructing intramural mass associated with the "coiled-spring" appearance generally raise the question of child abuse in any patient without appropriate accidental injury. In this study the radiologic features of resolving duodenal-jejunal hematoma are detailed in five abused children. The results show that the coiled-spring appearance is an acute phenomenon associated with a well-localized intramural hematoma. In the resolving phase, localized mural masses in the lateral aspect of the descending duodenum and fold thickening are indications of prior intramural hemorrhage. When these radiologic features are encountered in a child with nonspecific abdominal complaints, child abuse should be suspected. Furthermore, in patients with suspected occult trauma, resolution of abdominal symptoms should not deter the radiologist from performing an upper gastrointestinal tract series, which may provide evidence of child abuse.     

Increased plasma thyroid stimulating hormone in treated congenital hypothyroidism: relation to severity of hypothyroidism, plasma thyroid hormone status, and daily dose of thyroxine

Plasma thyroid stimulating hormone (TSH) concentrations obtained during the first four years of treatment in 418 children with congenital hypothyroidism, identified by neonatal screening, were examined in relation to paired measurements of plasma thyroxine (n = 1945), free thyroxine (n = 836), triiodothyronine (n = 480), and free triiodothyronine (n = 231), and estimated daily dose of thyroxine at the time of blood sampling. Overall, plasma TSH was above 7 mU/l in 1280 out of 2960 samples (43%); the percentage was not related to severity of hypothyroidism at diagnosis. Mean values for thyroxine and free thyroxine, and to a lesser extent free triiodothyronine, were consistently lower in samples with TSH concentrations over 7 mU/l and this was the case in patients with either severe or less severe hypothyroidism. Raised TSH concentrations were also associated with lower mean doses of thyroxine (micrograms/kg/day) but here the mean doses of thyroxine in children with severe hypothyroidism were higher than in the children with less severe hypothyroidism. The mean dose of thyroxine associated with low/normal TSH values was highest in the first 6 months and fell progressively. Thyroxine dose was significantly related to thyroxine and free thyroxine concentrations but not to triiodothyronine and free triiodothyronine and the latter appeared to be of limited value as measures of plasma thyroid hormone status during treatment.