Diagnostic yield of pelvic magnetic resonance venography in patients with cryptogenic stroke and patent foramen ovale.

BACKGROUND AND PURPOSE: Paradoxical embolization is frequently posited as a mechanism of ischemic stroke in patients with patent foramen ovale. Several studies have suggested that the deep lower extremity and pelvic veins might be an embolic source in cryptogenic stroke (CS) patients with patent foramen ovale. METHODS: Consecutive adult patients with ischemic stroke or transient ischemic attack and a patent foramen ovale who underwent pelvic magnetic resonance venography as part of an inpatient diagnostic evaluation were included in this single-center retrospective observational study to determine pelvic and lower extremity (LE) deep venous thrombosis (DVT) prevalence in CS versus non-CS stroke subtypes. RESULTS: Of 131 patients who met inclusion criteria, 126 (96.2%) also had LE duplex ultrasound data. DVT prevalence overall was 7.6% (95% confidence interval, 4.1-13.6), pelvic DVT 1.5% (95% confidence interval, 0.1-5.8), and LE DVT 7.1% (95% confidence interval, 3.6-13.2). One patient with a pelvic DVT also had a LE DVT. Comparing patients with CS (n=98) with non-CS subtypes (n=33), there was no significant difference in the prevalence of pelvic DVT (2.1% versus 0%, P=1), LE DVT (6.2% versus 10.3%, P=0.43), or any DVT (7.2% versus 9.1%, P=0.71). CONCLUSIONS: Among patients with ischemic stroke/transient ischemic attack and patent foramen ovale, the majority of detected DVTs were in LE veins rather than the pelvic veins and did not differ by stroke subtype. The routine inclusion of pelvic magnetic resonance venography in the diagnostic evaluation of CS warrants further prospective investigation.

Optimization of reduced-dose MDCT of thoracic aorta using iterative reconstruction.

OBJECTIVE: To evaluate the contribution of iterative reconstruction on image quality of reduced-dose multidetector computed tomography of the thoracic aorta. METHODS: A torso phantom was scanned using two tube potentials (80 and 120 kVp) and five different tube currents (110, 75, 40, 20, and 10 mAs). All images were reconstructed with both filtered back projection (FBP) and iterative reconstruction. Aortic attenuation, image noise within the thoracic aorta, signal-to-noise ratio, and sharpness of the aortic wall were quantified in the phantom for the two reconstruction algorithms. Data were analyzed using paired t test. A value of P < 0.05 was considered significant. RESULTS: The aortic attenuation was similar for FBP and iterative reconstruction (P > 0.05). Image noise level was lower (P < 0.0001), and image sharpness was higher (P = 0.046) with iterative reconstruction. Signal-to-noise ratios were higher with iterative reconstruction compared with those with FBP (P < 0.0001). Signal-to-noise ratio at 80 kVp with iterative reconstruction (9.8 ± 4.4) was similar to the signal-to-noise ratio at 120 kVp with FBP (8.4 ± 3.3) (P = 0.196). CONCLUSIONS: Less image noise and higher image sharpness may be achieved with iterative reconstruction in reduced-dose multidetector computed tomography of the thoracic aorta.

Effect of radiation dose and iterative reconstruction on lung lesion conspicuity at MDCT: does one size fit all?

OBJECTIVE: To evaluate the effect of different acquisition parameters and reconstruction algorithms in lung lesions conspicuity in chest MDCT. METHODS: An anthropomorphic chest phantom containing 6 models of lung disease (ground glass opacity, bronchial polyp, solid nodule, ground glass nodule, emphysema and tree-in-bud) was scanned using 80, 100 and 120 kVp, with fixed mAs ranging from 10 to 110. The scans were reconstructed using filtered back projection (FBP) and iterative reconstruction (IR) algorithms. Three blinded thoracic radiologists reviewed the images and scored lesions conspicuity and overall image quality. Image noise and radiation dose parameters were recorded. RESULTS: All acquisitions with 120 kVp received a score of 3 (acceptable) or higher for overall image quality. There was no significant difference between IR and FBP within each setting for overall image quality (p>0.05), even though image noise was significantly lower using IR (p<0.0001). When comparing specific lower radiation acquisition parameters 100 kVp/10 mAs [Effective Dose (ED): 0.238 mSv] vs 120 kVp/10 mAs (ED: 0.406 mSv) vs 80 kVp/40 mAs (ED: 0.434 mSv), we observed significant difference in lesions conspicuity (p<0.02), as well as significant difference in overall image quality, independent of the reconstruction algorithm (p<0.02), with higher scores on the 120 kV/10 mAs setting. Tree-in-bud pattern, ground glass nodule and ground glass opacity required lower radiation doses to get a diagnostic score using IR when compared to FBP. CONCLUSION: Designing protocols for specific lung pathologies using lower dose acquisition parameters is feasible, and by applying iterative reconstruction, radiologists may have better diagnostic confidence to evaluate some lesions in very low dose settings, preserving acceptable image quality.

Validade da rotina de realização do eletrocardiograma na avaliação pré-operatória de idosos / The validity of the electrocardiogram accomplishment in the elderly surgical patient preoperative evaluation

JUSTIFICATIVA E OBJETIVOS: Com os avanços médicos e o aumento da expectativa de vida, a população de idosos submetidos a procedimentos cirúrgicos vem aumentando. O paciente idoso tem maior morbiletalidade cardíaca peri-operatória do que o paciente jovem, mesmo quando assintomático. O eletrocardiograma (ECG) tem sido solicitado no período pré-operatório na tentativa de reduzir a morbiletalidade intra-operatória, porém sua eficácia é controversa. Não há consenso na literatura a respeito da indicação do ECG em pacientes idosos no período pré-operatório, o que motivou a realização deste estudo. O objetivo foi verificar retrospectivamente a validade da rotina de realização do ECG no período pré-operatório numa população de pacientes idosos cirúrgicos. MÉTODO: Análise retrospectiva de prontuários de pacientes a partir de 60 anos, submetidos a cirurgias diversas, durante o período de 6 meses. Os dados foram coletados para análise descritiva da população estudada; avaliação da incidência e dos tipos mais freqüentes de anormalidade dos ECG; análise comparativa dos pacientes com ECG normal e alterado em relação às diversas variáveis - idade, faixa etária, estado físico, presença de doença cardiovascular (DCV), complicações intra (CIO) e pós-operatórias (CPO).Também foram avaliados os pacientes sem DCV e aqueles com estado físico ASA I em relação às CIO e CPO, segundo os tipos de alterações do ECG e faixa etária. RESULTADOS: Foram analisados os prontuários de 481 pacientes, dos quais 287 continham ECG e destes, 88,8 por cento apresentavam anormalidades, sendo a mais freqüente, a alteração da repolarização ventricular. Não foi observada influência das variáveis estudadas sobre a incidência de ECG alterados. A incidência de alterações do ECG aumentou com o avanço da idade em todos pacientes estudados. Com o avanço da idade também ocorreu aumento da incidência de pacientes com ECG alterados associados com complicações intra-operatórias. As anormalidades eletrocardiográficas foram relevantes em relação à incidência de complicações intra-operatórias em todos os grupos estudados, principalmente as alterações secundárias à isquemia. CONCLUSÕES: Este estudo mostrou que, para a população cirúrgica idosa estudada, é válida a rotina de realização do eletrocardiograma como parte da avaliação pré-operatória.

[The validity of the electrocardiogram accomplishment in the elderly surgical patient preoperative evaluation.]. / Validade da rotina de realização do eletrocardiograma na avaliação pré-operatória de idosos.

BACKGROUND AND OBJECTIVES: Because of medical progress, life expectancy has been prolonged and the elderly population submitted to surgical procedures has been growing. Besides age-related cardiovascular changes, the prevalence of diseases, such as systemic hypertension, affect cardiovascular reserve and increase morbidity, mortality and perioperative outcomes. Electrocardiogram is useful in diagnosing previous myocardial infarction and arrhythmias. In the preoperative evaluation of these patients, ECG usefulness is a controversial subject. This study aimed at retrospectively evaluating the validity of preoperative ECG in elderly patients. METHODS: Retropective analysis of 481 patient records over 60 years old, submitted to different surgical procedures. Data were collected for description of the studied group; evaluation of most frequent electrocardiography abnormalities; comparative analysis between patients with normal and abnormal ECG related to age, ASA physical status, presence of cardiac disease intra and postoperative complications. Patients without cardiovascular disease (CVD) and physical status ASA I were separately analyzed. RESULTS: There were 481 patients, 287 of them with preoperative ECG and from those, 88,8% had abnormalities, being the most frequent ventricular repolarization changes.There was not influence of the parameters on the frequency of abnormal ECG. The abnormalitees of the ECG, especially those secondary to ischemia were related with intraoperative complications in all study groups. CONCLUSIONS: This study has shown that electrocardiogram is a valid routine for preoperative evaluation of elderly patients.