Applicability of 3D-CT facial reconstruction for forensic individual identification. (49/707)

Computed tomography (CT) is used in several clinical dentistry applications even by axial slices and two and three-dimensional reconstructed images (2D-CT and 3D-CT). The purpose of the current study is to assess the precision of linear measurements made in 3D-CT using craniometric patterns for individual identification in Forensic Dentistry. Five cadaver heads were submitted to a spiral computed tomography using axial slices, and 3D-CT reconstructions were obtained by volume rendering technique with computer graphics tools. Ten (10) craniometric measurements were determined in 3D-CT images by two examiners independently, twice each, and the standard error of intra- and inter-examiner measurements was assessed. The results demonstrated a low standard error of those measurements, from 0.85% to 3.09%. In conclusion, the linear measurements obtained in osseous and soft tissue structures were considered to be precise in 3D-CT with high imaging quality and resolution.  (+info)

Helical CT scanning in the diagnosis of pulmonary embolism. (50/707)

CT pulmonary angiography has become the screening exam of choice to evaluate for pulmonary embolism (PE), especially in subjects with an abnormal chest radiograph. A good-quality CT pulmonary angiogram has a high accuracy rate for the evaluation of PE. Investigators have reported that subsegmental emboli can be missed; however, visualization of smaller arterial branches and, therefore, detection of small emboli have improved with the availability of multidetector scanners. Some of the advantages of using CT for PE compared to lung scintigraphy include: (1) direct visualization of emboli on CT; (2), evaluation of lung parenchyma and mediastinum (this may provide an alternate diagnosis); (3) capability to acquire a CT venogram without additional contrast with 'one-stop examination' for the evaluation of thromboembolic disease.  (+info)

Transcatheter angioplasty for acquired pulmonary vein stenosis after radiofrequency ablation. (51/707)

BACKGROUND: Pulmonary vein stenosis has recently been recognized as a complication of radiofrequency ablation for atrial fibrillation. This study evaluates the presentation of affected patients and the role of transcatheter therapy for this patient population. METHODS AND RESULTS: This study used a retrospective review of data from 19 patients (age, 51+/-13 years) with pulmonary vein stenosis who underwent catheterization and angiography between December 2000 and December 2002. Quantitative perfusion and spiral CT scans were performed for initial diagnosis and follow-up. The median duration between radiofrequency ablation and the reported onset of respiratory symptoms for 18 of 19 patients was 7.5 weeks (0.1 to 48). After the onset of symptoms, all but two patients were initially misdiagnosed with a symptoms-to-diagnosis duration of 16 weeks (2-59). At initial catheterization, 17 of 19 patients had angioplasty in 30 veins with stent placement in 5 vessels when a flap occurred. Overall vessel diameter increased from 2.6+/-1.6 to 6.6+/-2.4 mm (P<0.0001). There were 4 procedure-related adverse events but no long-term sequelae. Immediate follow-up showed improved flow to involved lung segments. At a median follow-up of 43 weeks (2-92), although repeat angioplasty for restenosis was necessary in 8 of 17 patients, 15 of 17 patients currently have no or minimal persistent symptoms. CONCLUSIONS: Pulmonary vein stenosis after radiofrequency ablation for atrial fibrillation is often misdiagnosed. Although further follow-up is necessary to determine long-term success, our data indicate better pulmonary vein flow and symptomatic improvement in the majority of patients undergoing dilation of postablation pulmonary vein stenosis.  (+info)

Quantitative tumor apoptosis imaging using technetium-99m-HYNIC annexin V single photon emission computed tomography. (52/707)

PURPOSE: Radiolabeled annexin V may allow for repetitive and selective in vivo identification of apoptotic cell death without the need for invasive biopsy. This study reports on the relationship between quantitative technetium-99m- (99mTc-) 6-hydrazinonicotinic (HYNIC) radiolabeled annexin V tumor uptake, and the number of tumor apoptotic cells derived from histologic analysis. PATIENTS AND METHODS: Twenty patients (18 men, two women) suspected of primary (n = 19) or recurrent (n = 1) head and neck carcinoma were included. All patients underwent a spiral computed tomography (CT) scan, 99mTc-HYNIC annexin V tomography, and subsequent surgical resection of the suspected primary or recurrent tumor. Quantitative 99mTc-HYNIC annexin V uptake in tumor lesions divided by the tumor volume, derived from CT, was related to the number of apoptotic cells per tumor high-power field derived from terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end-labeling (TUNEL) assays performed on sectioned tumor slices. RESULTS: Diagnosis was primary head and neck tumor in 18 patients, lymph node involvement of a cancer of unknown primary origin in one patient, and the absence of recurrence in one patient. Mean percentage absolute tumor uptake of the injected dose per cubic centimeter tumor volume derived from tomographic images was 0.0003% (standard deviation [SD], 0.0004%) at 1 hour postinjection (PI) and 0.0001% (SD, 0.0000%) at 5 to 6 hours PI (P =.012). Quantitative 99mTc-HYNIC annexin V tumor uptake correlated well with the number of apoptotic cells if only tumor samples with no or minimal amounts of necrosis were considered. CONCLUSION: In the absence of necrosis, absolute 99mTc-HYNIC annexin V tumor uptake values correlate well with the number of apoptotic cells derived from TUNEL assays.  (+info)

Dynamic CT myelography: a technique for localizing high-flow spinal cerebrospinal fluid leaks. (53/707)

In some patients with spontaneous spinal CSF leaks, leaks are numerous or tears are so large that extrathecal myelographic contrast material is seen at multiple levels during CT, making identification of their source impossible. This study introduces a dynamic CT myelographic technique that provides high temporal and spatial resolution. In this technical note, we describe the utility of this technique in four patients with challenging high-flow spinal CSF leaks.  (+info)

Identification of rounded atelectasis in workers exposed to asbestos by contrast helical computed tomography. (54/707)

Rounded atelectasis (RA) is a benign and unusual form of subpleural lung collapse that has been described mostly in asbestos-exposed workers. This form of atelectasis manifests as a lung nodule and can be confused with bronchogenic carcinoma upon conventional radiologic examination. The objective of the present study was to evaluate the variation in contrast uptake in computed tomography for the identification of asbestos-related RA in Brazil. Between January 1998 and December 2000, high-resolution computed tomography (HRCT) was performed in 1658 asbestos-exposed workers. The diagnosis was made in nine patients based on a history of prior asbestos exposure, the presence of characteristic (HRCT) findings and lesions unchanged in size over 2 years or more. In three of them the diagnosis was confirmed during surgery. The dynamic contrast enhancement study was modified to evaluate nodules and pulmonary masses. All nine patients with RA received iodide contrast according to weight. The average enhancement after iodide contrast was infused, reported as Hounsfield units (HU), increased from 62.5+/-9.7 to 125.4+/-20.7 (P < 0.05), with a mean enhancement of 62.5+/-19.7 (range 40 to 89) and with a uniform dense opacification. In conclusion, in this study all patients with RA showed contrast enhancement with uniform dense opacification. The main clinical implication of this finding is that this procedure does not permit differentiation between RA and malignant pulmonary neoplasm.  (+info)

Endovascular repair of abdominal aortic aneurysm without preoperative arteriography. (55/707)

OBJECTIVE: Clinical trials of endovascular aortic aneurysm repair (EVAR) have required both preoperative aortography and computed tomography (CT). We codeveloped specialized three-dimensional (3-D) reconstruction and computer-aided measurement, planning, and simulation software (3-D CAMPS) based on CT or magnetic resonance imaging, to eliminate the need for preoperative arteriography. METHODS: EVAR with 3-D CAMPS as the sole preoperative imaging method was performed in 196 patients from 1996 to 2001, with six endograft types in three configurations. Physical examination, abdominal radiography, and CT (3D-CAMPS) were performed at 1, 6, and 12 months, then annually. RESULTS: For a subset of cases in which a comparison could be made, 3-D CAMPS was superior to angiography for prediction of endograft length and iliac access. Hospital mortality was zero, and 30-day mortality was 0.5%. In three patients immediate conversion to open repair (1.5%) was necessary because of previously unknown stent-graft mechanical limits. Incidence of endoleak was 15% at 1 month, 10% at 6 months, 6% at 12 months, and 7% at 24 months, and 92% of endoleaks were type II. Mean follow-up was 18 months. Aneurysm-related mortality was zero. Nineteen secondary procedures (all endovascular) were performed in 16 patients (8%). For all graft types, freedom from secondary procedure was 94% at 1 year and 90% at 2 years, and this was better for endografts ultimately approved by the US Food and Drug Administration (96% at 1 year, 95% at 2 years; P =.02). No known measurement-related complications occurred in the series. Results for secondary intervention and endoleak compare favorably to series with similar endograft types. CONCLUSIONS: EVAR can be performed with 3-D CAMPS as the sole preoperative imaging method to achieve outcomes comparable to the best series published for each endograft type. CT with 3-D CAMPS can effectively eliminate the need for preoperative arteriography and avert associated morbidity, expense, and exposure to contrast agent and radiation.  (+info)

Pulmonary embolism: differences in presentation between older and younger patients. (56/707)

BACKGROUND: the incidence of pulmonary embolism increases with age but the 'classical' presentation of acute pulmonary embolism may not occur in older persons. OBJECTIVES: to compare the clinical presentation of younger and older patients with acute pulmonary embolism. DESIGN: retrospective identification of 60 consecutive cases of spiral computed tomography confirmed acute pulmonary embolism over a 3-year period, with blinded review of radiological films and electrocardiographs, and analysis of clinical presentation. SETTING: a district general hospital serving a population of 200,000 people. SUBJECTS: 31 younger and 29 older patients with acute pulmonary embolism. RESULTS: older persons less often complained of pleuritic chest pain (P < 0.02), particularly as their primary presenting complaint (P < 0.002). Twenty-four percent of older but just 3% of younger persons presented with collapse (P < 0.02), despite similar proportions of central and peripheral emboli in the two groups. Older persons were more often cyanosed (P = 0.05) and hypoxic (P < 0.04) than younger persons but there were no significant differences with respect to heart rate, respiratory rate or mean arterial blood pressure. CONCLUSIONS: older people present atypically with acute pulmonary embolism, potentially leading to delays in diagnosis and initiation of treatment. Collapse is a particularly important symptom of acute pulmonary embolism in older persons, even in the absence of pain.  (+info)