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1.
Eur J Radiol ; 119: 108657, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31521876

RESUMO

PURPOSE: This study investigated the impact of gender differences on the diagnostic performance of machine-learning based coronary CT angiography (cCTA)-derived fractional flow reserve (CT-FFRML) for the detection of lesion-specific ischemia. METHOD: Five centers enrolled 351 patients (73.5% male) with 525 vessels in the MACHINE (Machine leArning Based CT angiograpHy derIved FFR: a Multi-ceNtEr) registry. CT-FFRML and invasive FFR ≤ 0.80 were considered hemodynamically significant, whereas cCTA luminal stenosis ≥50% was considered obstructive. The diagnostic performance to assess lesion-specific ischemia in both men and women was assessed on a per-vessel basis. RESULTS: In total, 398 vessels in men and 127 vessels in women were included. Compared to invasive FFR, CT-FFRML reached a sensitivity, specificity, positive predictive value, and negative predictive value of 78% (95%CI 72-84), 79% (95%CI 73-84), 75% (95%CI 69-79), and 82% (95%CI: 76-86) in men vs. 75% (95%CI 58-88), 81 (95%CI 72-89), 61% (95%CI 50-72) and 89% (95%CI 82-94) in women, respectively. CT-FFRML showed no statistically significant difference in the area under the receiver-operating characteristic curve (AUC) in men vs. women (AUC: 0.83 [95%CI 0.79-0.87] vs. 0.83 [95%CI 0.75-0.89], p = 0.89). CT-FFRML was not superior to cCTA alone [AUC: 0.83 (95%CI: 0.75-0.89) vs. 0.74 (95%CI: 0.65-0.81), p = 0.12] in women, but showed a statistically significant improvement in men [0.83 (95%CI: 0.79-0.87) vs. 0.76 (95%CI: 0.71-0.80), p = 0.007]. CONCLUSIONS: Machine-learning based CT-FFR performs equally in men and women with superior diagnostic performance over cCTA alone for the detection of lesion-specific ischemia.


Assuntos
Angiografia por Tomografia Computadorizada/normas , Estenose Coronária/diagnóstico por imagem , Isquemia Miocárdica/diagnóstico por imagem , Angiografia por Tomografia Computadorizada/métodos , Angiografia Coronária/métodos , Angiografia Coronária/normas , Estenose Coronária/fisiopatologia , Métodos Epidemiológicos , Feminino , Reserva Fracionada de Fluxo Miocárdico/fisiologia , Hemodinâmica/fisiologia , Humanos , Aprendizado de Máquina , Masculino , Pessoa de Meia-Idade , Isquemia Miocárdica/fisiopatologia , Fatores Sexuais , Tomografia Computadorizada Espiral/métodos , Tomografia Computadorizada Espiral/normas
2.
Cancer Imaging ; 19(1): 24, 2019 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-31097025

RESUMO

OBJECTIVE: To discuss the diagnostic value of multislice spiral tomography (CT) combined with CT angiography (CTA) technology in intra-abdominal undescended testis secondary seminoma cases. METHODS: We retrospectively analyzed the CT and CTA imaging features of CT and CTA findings of nine patients with an intra-abdominal undescended testis secondary seminoma. RESULTS: The tumors in all nine patients were mainly solid, and the average CT value was 38.4 ± 3.4 HU. Low-density areas of various sizes were visible in the tumors, and calcifications were detected in two patients. The tumors in eight patients had a complete capsule, which pressed on the surrounding structures. In one patient, the tumor had an incomplete capsule, which invaded the surrounding structures. Some of the solid tumors showed progressive and slight enhancement on the CT-enhanced scans. The values in the arterial phase, venous phase, and delayed phase were 46.3 ± 5.1 (40-55 HU), 57.3 ± 7.3HU (48-68 HU), and 65.1 ± 7.2HU (56-77 HU), respectively, with an average increase rate of 27.0 ± 7.2 HU. No enhancement was found in low-density areas on the CTA scans, and the supply arteries of the tumors in the nine patients all originated from the abdominal aortic wall 2-3 cm below the renal ostia. These arteries became thickened and tortuous when near the tumors, and there were no branching vessels. In eight patients, the supply arteries of the tumors originated from the posterior tumor and ended inside the tumor, and they originated from anterior of the tumor in one patient. Testicular venous drainage was detected in three patients, and lymph node metastasis in the abdominal aorta detected in two cases. CONCLUSION: An intra-abdominal undescended testis secondary seminoma exhibits a characteristic appearance on CT. CTA shows a three-dimensional testicular vascular pedicle sign of a seminoma. A combination of CT and CTA can improve the diagnostic accuracy of an intra-abdominal undescended testis secondary seminoma.


Assuntos
Angiografia por Tomografia Computadorizada/normas , Criptorquidismo/diagnóstico por imagem , Seminoma/diagnóstico por imagem , Neoplasias Testiculares/diagnóstico por imagem , Tomografia Computadorizada Espiral/normas , Adulto , Idoso , Criptorquidismo/complicações , Humanos , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Seminoma/etiologia , Seminoma/patologia , Neoplasias Testiculares/etiologia , Neoplasias Testiculares/patologia
3.
Phys Med Biol ; 63(4): 04NT04, 2018 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-29360098

RESUMO

To determine if the parameters relating lung tissue displacement to a breathing surrogate signal in a previously published respiratory motion model vary with the rate of breathing during image acquisition. An anesthetized pig was imaged using multiple fast helical scans to sample the breathing cycle with simultaneous surrogate monitoring. Three datasets were collected while the animal was mechanically ventilated with different respiratory rates: 12 bpm (breaths per minute), 17 bpm, and 24 bpm. Three sets of motion model parameters describing the correspondences between surrogate signals and tissue displacements were determined. The model error was calculated individually for each dataset, as well asfor pairs of parameters and surrogate signals from different experiments. The values of one model parameter, a vector field denoted [Formula: see text] which related tissue displacement to surrogate amplitude, determined for each experiment were compared. The mean model error of the three datasets was 1.00 ± 0.36 mm with a 95th percentile value of 1.69 mm. The mean error computed from all combinations of parameters and surrogate signals from different datasets was 1.14 ± 0.42 mm with a 95th percentile of 1.95 mm. The mean difference in [Formula: see text] over all pairs of experiments was 4.7% ± 5.4%, and the 95th percentile was 16.8%. The mean angle between pairs of [Formula: see text] was 5.0 ± 4.0 degrees, with a 95th percentile of 13.2 mm. The motion model parameters were largely unaffected by changes in the breathing rate during image acquisition. The mean error associated with mismatched sets of parameters and surrogate signals was 0.14 mm greater than the error achieved when using parameters and surrogate signals acquired with the same breathing rate, while maximum respiratory motion was 23.23 mm on average.


Assuntos
Movimentos dos Órgãos , Taxa Respiratória , Tomografia Computadorizada Espiral/métodos , Animais , Pulmão/diagnóstico por imagem , Suínos , Tomografia Computadorizada Espiral/normas
4.
J Cardiovasc Comput Tomogr ; 11(6): 482-488, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29031436

RESUMO

BACKGROUND: No established measure of concentric left ventricular wall hypertrophy (cLVH) on routine computed tomography (CT) of the adult chest currently exists. The objective of this study was to identify and test linear measures for the detection of cLVH using transthoracic echocardiography (TTE) as the reference standard. METHODS: Contrast-enhanced non-electrocardiogram-gated chest CTs acquired within two weeks of TTE were retrospectively evaluated. Two radiologists independently made trans-axial measurements in the proximal half of the left ventricle at its approximate widest internal diameter: maximum septal thickness (sept), maximum lateral wall thickness (lat), and inner (Id) and outer (Od) wall-wall diameters at the level of greatest combined myocardial thickness. The sum of sept and lat, hereafter Thmax, and modified cross-sectional area (Amod = Od2 - Id2) were calculated. Sept, lat, Thmax, and Amod were evaluated by receiver operating characteristic (ROC) curves using TTE as the reference standard. Thresholds were optimized for specificity and applied to a validation cohort. Inter-rater agreement was assessed by a simple unweighted Kappa statistic (κ). RESULTS: Sept and Amod were selected based on areas under the ROC curves of 0.75 and 0.71, respectively, using 100 CTs. Thresholds of 1.6 cm and 30 cm2, respectively, showed similar specificities of 98% with sensitivities of 27% and 30%, respectively. Applied to a validation cohort of 100 CTs, sept had higher combined positive predictive value (75%), inter-rater agreement (κ = 0.58), specificity (91%), and sensitivity (24%). CONCLUSION: Linear measures demonstrate utility in the diagnosis of cLVH on routine contrast-enhanced chest CT.


Assuntos
Meios de Contraste/administração & dosagem , Ecocardiografia , Hipertrofia Ventricular Esquerda/diagnóstico por imagem , Tomografia Computadorizada Espiral/métodos , Função Ventricular Esquerda , Remodelação Ventricular , Adulto , Idoso , Idoso de 80 Anos ou mais , Área Sob a Curva , Ecocardiografia/normas , Humanos , Hipertrofia Ventricular Esquerda/fisiopatologia , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Valor Preditivo dos Testes , Curva ROC , Interpretação de Imagem Radiográfica Assistida por Computador , Padrões de Referência , Reprodutibilidade dos Testes , Estudos Retrospectivos , Tomografia Computadorizada Espiral/normas , Adulto Jovem
5.
Vestn Rentgenol Radiol ; (1): 23-9, 2017.
Artigo em Russo | MEDLINE | ID: mdl-30247858

RESUMO

Objective: To compare a radiation dose obtained during standard digital radiography, tomosynthesis, and multislice spiral computed tomography (MSCT). Material and Methods: Life-size full body pediatric anthropomorphic mannequin phantom was examined with a Fujifilm FDR Ac Selerate 200 X-ray diagnostic apparatus and a Toshiba Aquilion Prime 64 computed scanner using the Piranha dosimetry equipment, as well as Gammex planar target, for comparison of the resolution of the apparatus. The effective radiation doses were calculated for different anatomical regions with the formulas specified in the methodical instructions, using the coefficients K and Kd. Results: The tables and graphs comparing the radiation dose when using different radiation diagnostic techniques were presented. The resolution of standard digital radiography versus that of tomosynthesis was analyzed. Fluctuations of the doses obtained were associated with the difference in the volume of irradiated tissue and in the presence of the doses in the irradiated volume of organs with high radiosensitivity. Optimal physical and technical parameters of photography were proposed, which could reduce a dose load on the patient, without significantly losing the quality of films. Conclusion: The effective doses of tomosynthesis were significantly higher than those of standard digital radiography (p < 0.05) while those of (MSCT) were above those of both X-ray and tomosynthesis, and the resolution of the latter was slightly lower.


Assuntos
Antropometria , Imagens de Fantasmas , Doses de Radiação , Tomografia Computadorizada Espiral , Tomografia por Raios X , Antropometria/instrumentação , Antropometria/métodos , Criança , Humanos , Manequins , Saúde Radiológica/métodos , Saúde Radiológica/normas , Federação Russa , Tomografia Computadorizada Espiral/métodos , Tomografia Computadorizada Espiral/normas , Tomografia por Raios X/métodos , Tomografia por Raios X/normas
6.
Vestn Rentgenol Radiol ; (1): 36-43, 2017.
Artigo em Russo | MEDLINE | ID: mdl-30247860

RESUMO

The paper considers the main provisions of the 2009 RECIST guidelines (version 1.1.) criteria for a standard approach to measuring lung tumor lesions and assessing the dynamics of the tumor process during treatment. This paper contains a list of conditions for carrying out multislice spiral computed tomography, under which the latter becomes maximally reproducible for the same patient, as well as an assessment of the course of the disease does optimal.


Assuntos
Neoplasias Pulmonares , Pulmão/diagnóstico por imagem , Monitorização Fisiológica , Critérios de Avaliação de Resposta em Tumores Sólidos , Tomografia Computadorizada Espiral , Humanos , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/terapia , Monitorização Fisiológica/métodos , Monitorização Fisiológica/normas , Federação Russa , Tomografia Computadorizada Espiral/métodos , Tomografia Computadorizada Espiral/normas
7.
Phys Med Biol ; 61(4): 1416-38, 2016 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-26807931

RESUMO

Correction for rigid object motion in helical CT can be achieved by reconstructing from a modified source-detector orbit, determined by the object motion during the scan. This ensures that all projections are consistent, but it does not guarantee that the projections are complete in the sense of being sufficient for exact reconstruction. We have previously shown with phantom measurements that motion-corrected helical CT scans can suffer from data-insufficiency, in particular for severe motions and at high pitch. To study whether such data-insufficiency artefacts could also affect the motion-corrected CT images of patients undergoing head CT scans, we used an optical motion tracking system to record the head movements of 10 healthy volunteers while they executed each of the 4 different types of motion ('no', slight, moderate and severe) for 60 s. From these data we simulated 354 motion-affected CT scans of a voxelized human head phantom and reconstructed them with and without motion correction. For each simulation, motion-corrected (MC) images were compared with the motion-free reference, by visual inspection and with quantitative similarity metrics. Motion correction improved similarity metrics in all simulations. Of the 270 simulations performed with moderate or less motion, only 2 resulted in visible residual artefacts in the MC images. The maximum range of motion in these simulations would encompass that encountered in the vast majority of clinical scans. With severe motion, residual artefacts were observed in about 60% of the simulations. We also evaluated a new method of mapping local data sufficiency based on the degree to which Tuy's condition is locally satisfied, and observed that areas with high Tuy values corresponded to the locations of residual artefacts in the MC images. We conclude that our method can provide accurate and artefact-free MC images with most types of head motion likely to be encountered in CT imaging, provided that the motion can be accurately determined.


Assuntos
Movimentos da Cabeça , Tomografia Computadorizada Espiral/métodos , Artefatos , Cabeça/diagnóstico por imagem , Humanos , Amplitude de Movimento Articular , Tomografia Computadorizada Espiral/normas
8.
Int J Radiat Oncol Biol Phys ; 93(4): 925-33, 2015 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-26530763

RESUMO

PURPOSE: To develop a technique that assesses the accuracy of the breathing phase-specific volume image generation process by patient-specific breathing motion model using the original free-breathing computed tomographic (CT) scans as ground truths. METHODS: Sixteen lung cancer patients underwent a previously published protocol in which 25 free-breathing fast helical CT scans were acquired with a simultaneous breathing surrogate. A patient-specific motion model was constructed based on the tissue displacements determined by a state-of-the-art deformable image registration. The first image was arbitrarily selected as the reference image. The motion model was used, along with the free-breathing phase information of the original 25 image datasets, to generate a set of deformation vector fields that mapped the reference image to the 24 nonreference images. The high-pitch helically acquired original scans served as ground truths because they captured the instantaneous tissue positions during free breathing. Image similarity between the simulated and the original scans was assessed using deformable registration that evaluated the pointwise discordance throughout the lungs. RESULTS: Qualitative comparisons using image overlays showed excellent agreement between the simulated images and the original images. Even large 2-cm diaphragm displacements were very well modeled, as was sliding motion across the lung-chest wall boundary. The mean error across the patient cohort was 1.15 ± 0.37 mm, and the mean 95th percentile error was 2.47 ± 0.78 mm. CONCLUSION: The proposed ground truth-based technique provided voxel-by-voxel accuracy analysis that could identify organ-specific or tumor-specific motion modeling errors for treatment planning. Despite a large variety of breathing patterns and lung deformations during the free-breathing scanning session, the 5-dimensionl CT technique was able to accurately reproduce the original helical CT scans, suggesting its applicability to a wide range of patients.


Assuntos
Tomografia Computadorizada Quadridimensional/métodos , Neoplasias Pulmonares/diagnóstico por imagem , Movimento , Planejamento da Radioterapia Assistida por Computador/métodos , Respiração , Tomografia Computadorizada Espiral/métodos , Algoritmos , Artefatos , Protocolos Clínicos , Expiração , Tomografia Computadorizada Quadridimensional/normas , Humanos , Inalação , Garantia da Qualidade dos Cuidados de Saúde , Planejamento da Radioterapia Assistida por Computador/normas , Reprodutibilidade dos Testes , Tomografia Computadorizada Espiral/normas
9.
PLoS One ; 10(6): e0131243, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26125549

RESUMO

INTRODUCTION: The purpose of the present study was to evaluate the influence of different variables on radiation dose and image quality based on a national database. MATERIALS AND METHODS: Taiwan's Ministry of Health and Welfare requested all radiology departments to complete a questionnaire for each of their CT scanners. Information gathered included all scanning parameters for CT head scans. For the present analysis, CT machines were divided into three subgroups: single slice CT (Group A); multi-detector CT (MDCT) with 2-64 slices (Group B); and MDCT with more than 64 slices (Group C). Correlations between computed tomography dose index (CTDI) and signal-to-noise ratio (SNR) with cumulated tube rotation number (CTW(n)) and cumulated tube rotation time (CTW(s)), and sub group analyses of CTDI and SNR across the three groups were performed. RESULTS: CTDI values demonstrated a weak correlation (r = 0.33) with CTW(n) in Group A. SNR values demonstrated a weak negative correlation (r = -0.46) with CTW(n) in Group C. MDCT with higher slice numbers used more tube potential resulting in higher effective doses. There were both significantly lower CTDI and SNR values in helical mode than in axial mode in Group B, but not Group C. CONCLUSION: CTW(n) and CTW(s) did not influence radiation output. Helical mode is more often used in MDCT and results in both lower CTDI and SNR compared to axial mode in MDCT with less than 64 slices.


Assuntos
Cabeça/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Adulto , Interpretação Estatística de Dados , Humanos , Tomografia Computadorizada Multidetectores/normas , Tomografia Computadorizada Multidetectores/estatística & dados numéricos , Controle de Qualidade , Doses de Radiação , Razão Sinal-Ruído , Inquéritos e Questionários , Taiwan , Tomografia Computadorizada Espiral/normas , Tomografia Computadorizada Espiral/estatística & dados numéricos , Tomografia Computadorizada por Raios X/normas , Tomografia Computadorizada por Raios X/estatística & dados numéricos
11.
Eur Rev Med Pharmacol Sci ; 18(23): 3619-28, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25535131

RESUMO

OBJECTIVE: To evaluate the relationship between gantry rotation time, heart rate and image quality during multislice spiral CT coronary angiography (MSCTCA). PATIENTS AND METHODS: Data of 83 patients who underwent MSCTCA were reviewed. Based on the ratio between cardiac cycle and gantry rotation time, the patients were divided into two groups. Patients whose heart rates fell in the resonance frequency (the cardiac cycle / gantry rotational time ratio of 1.5, 2 or 2.5) ± 2 bpm were classified as synchronous (25 cases), while the remaining 58 patients (included a subgroup of 34 cases in whom heart rates were the same as in synchronous group but who had a different gantry rotation time). comprised the asynchronous group. Image qualities were compared between both groups. RESULTS: In the synchronous group, most (199/287; 69.33%) images were poor. When gantry rotation time was changed in the subgroup of the asynchronous group, the majority (423/442 or 95.70%) of images improved. There was a significant difference (p < 0.001) in the image quality among these patients. In 58 patients from asynchronous group, 757 segments of coronary arteries were evaluated, and 716 segments were of best quality (716/757; 94.58%). CONCLUSIONS: When heart rate and gantry rotation time correlate and synchronous, the so-called frequency harmonics, coronary artery image quality is poor. However, by changing gantry rotation time to avoid the harmonic helps to improve the image quality on MSCTCA. Based on the patient's heart rate, appropriate gantry rotation time can be selected in order to avoid resonance and obtain high quality images.


Assuntos
Angiografia Coronária/normas , Vasos Coronários/diagnóstico por imagem , Vasos Coronários/fisiologia , Frequência Cardíaca/fisiologia , Tomografia Computadorizada Multidetectores/normas , Rotação , Adulto , Idoso , Idoso de 80 Anos ou mais , Angiografia Coronária/métodos , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Processamento de Imagem Assistida por Computador/normas , Masculino , Pessoa de Meia-Idade , Tomografia Computadorizada Multidetectores/métodos , Fatores de Tempo , Tomografia Computadorizada Espiral/métodos , Tomografia Computadorizada Espiral/normas
12.
Eur Spine J ; 23(10): 2166-74, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25047653

RESUMO

PURPOSE: To conduct a retrospective multicenter study to investigate the accuracy of pedicle screw (PS) placement in the cervical spine by freehand technique and the related complications in various pathological conditions including trauma, rheumatoid arthritis, degenerative conditions and others. METHODS: 283 patients with 1,065 PSs in the cervical spine who were treated at eight spine centers and finished postoperative CT scan were enrolled. The numbers of placed PSs were 608 for trauma, 180 for rheumatoid arthritis (RA), 199 for spondylosis, and 78 for others. Malposition grades on CT image in the axial plane were defined as grade 0 (G-0) correct placement, grade 1 (G-1): malposition by less than half screw diameter, grade 2 (G-2): malposition by more than half screw diameter. The direction of malposition was classified into four categories: medial, lateral, superior and inferior. RESULTS: Overall malposition rate was 14.8 % (9.6 % in G-1 and 5.3 % in G-2). The highest malposition rate was 26.7 % for RA, followed by 16.6 % for spondylosis, and 11.2 % for trauma. The malposition rate for RA was significantly higher than those for other pathologies. 79.7 % of the malpositioned screws were placed laterally. Though intraoperative vertebral artery injury was observed in two patients with RA, there were no serious complications during a minimal 2-year follow-up. CONCLUSIONS: Malposition rate of PS placement in the cervical spine by freehand technique was high in rheumatoid patients even when being performed by experienced spine surgeons. Any guidance tools including navigation systems are recommended for placement of cervical PSs in patients with RA.


Assuntos
Vértebras Cervicais/diagnóstico por imagem , Vértebras Cervicais/cirurgia , Fluoroscopia/normas , Fraturas da Coluna Vertebral/cirurgia , Fusão Vertebral/normas , Tomografia Computadorizada Espiral/normas , Adulto , Idoso , Idoso de 80 Anos ou mais , Artrite Reumatoide/cirurgia , Feminino , Fluoroscopia/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Lesões do Pescoço/diagnóstico por imagem , Lesões do Pescoço/cirurgia , Parafusos Pediculares , Período Pós-Operatório , Estudos Retrospectivos , Fraturas da Coluna Vertebral/diagnóstico por imagem , Fusão Vertebral/métodos , Espondilose , Tomografia Computadorizada Espiral/métodos
13.
Anesth Analg ; 119(4): 875-9, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25025586

RESUMO

BACKGROUND: Although the nasopharynx is a commonly used temperature-monitoring site during general anesthesia, it is unknown whether the position of nasopharyngeal temperature probes placed blindly by anesthesia practitioners is optimal. The purposes of this study were (1) to determine where the nasopharyngeal mucosa is in closest proximity to the internal carotid artery (ICA) and (2) to evaluate the tip position of nasopharyngeal temperature probes that were placed by anesthesiology residents and nurse anesthetists. METHODS: In the first phase of the study, we reviewed enhanced axial computed tomography images of 100 patients to determine where the nasopharyngeal mucosa was in closest proximity to the left or the right ICA. The distance from this point to the nares was then measured in the sagittal image. In the second phase of the study, nasendoscopy was used to evaluate the positioning of nasopharyngeal temperature probes placed by anesthesiology residents (244 patients) or nurse anesthetists (116 patients). Malpositioned probes were repositioned to an optimal location, and the temperature differences were recorded. RESULTS: In the computed tomography images, the mucosa in closest proximity to the ICA was in the upper, mid-, and lower nasopharynx in 60%, 38%, and 2% of patients, respectively. The average distances between the ICA and the nasopharyngeal mucosa in the upper portion were significantly shorter than those in the lower portion (female: 9.4 vs 16.8 mm, P < 0.001; male: 12.4 vs 18.8 mm, P < 0.001). The average distances (95% prediction interval) from the nares to the upper portion of the nasopharynx through the inferior meatus were 9.1 (8.1-10.2) cm in females and 9.7 (8.6-10.8) cm in males. Temperature probes were correctly positioned in the upper or mid-nasopharynx by residents and nurses in 43% (95% confidence interval [CI], 37%-49%) and 41% (95% CI, 36%-50%), respectively. When the probe was inadvertently placed in the nasal cavity, the median (95% CI) temperature difference from the upper nasopharynx was 0.2°C (0.15°C-0.25°C). CONCLUSIONS: The closest portion of the nasopharyngeal mucosa to the ICA is within the upper or mid-nasopharynx. The depth from the nares to the upper one-third of the nasopharynx is approximately 10 cm. Less than half of nasopharyngeal temperature probes placed blindly by practitioners were optimally positioned.


Assuntos
Temperatura Corporal/fisiologia , Monitorização Intraoperatória/instrumentação , Monitorização Intraoperatória/normas , Mucosa Nasal/diagnóstico por imagem , Mucosa Nasal/fisiologia , Nasofaringe/diagnóstico por imagem , Nasofaringe/fisiologia , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tomografia Computadorizada Espiral/normas
14.
Ann R Coll Surg Engl ; 95(7): 473-6, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24112491

RESUMO

INTRODUCTION: Although colonoscopy and computed tomography (CT) colonography in expert hands are the most sensitive investigations for colorectal cancer, some patients may not tolerate the necessary bowel preparation and insufflation of gas into the colon. We assessed the performance of unprepared contrast CT for the detection of colorectal cancer. METHODS: A retrospective review was undertaken of all patients who had contrast CT of the abdomen and pelvis and then went on to have colonoscopy at our institutions between 2007 and 2010. RESULTS: Overall, 96 patients were identified as having had CT prior to colonoscopy. The sensitivity of CT in detecting colorectal cancer was 100% (95% confidence interval [CI]: 19.8-100%) and the specificity was 95.7% (95% CI: 88.8-98.6%). The positive predictive value was 33.3% (95% CI: 6.0-75.9%) and the negative predictive value was 100% (95% CI: 94.8-100%). CONCLUSIONS: Non-targeted CT that is negative for colorectal malignancy is usually reassuring but the decision for further investigations should be made on a case-by-case basis, taking into account of the likelihood of underlying colorectal malignancy and the underlying co-morbidities of the patient. However, video colonoscopy is usually necessary to assess positive CT findings.


Assuntos
Neoplasias Colorretais/diagnóstico por imagem , Tomografia Computadorizada por Raios X/normas , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Colonografia Tomográfica Computadorizada/normas , Colonoscopia/normas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Sensibilidade e Especificidade , Tomografia Computadorizada Espiral/normas , Adulto Jovem
15.
Int J Radiat Oncol Biol Phys ; 85(3): 862-5, 2013 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-22836060

RESUMO

PURPOSE: To compare Tomotherapy's megavoltage computed tomography bony anatomy autoregistration with the best achievable registration, assuming no deformation and perfect knowledge of planning target volume (PTV) location. METHODS AND MATERIALS: Distance-to-agreement (DTA) of the PTV was determined by applying a rigid-body shift to the PTV region of interest of the prostate from its reference position, assuming no deformations. Planning target volume region of interest of the prostate was extracted from the patient archives. The reference position was set by the 6 degrees of freedom (dof)-x, y, z, roll, pitch, and yaw-optimization results from the previous study at this institution. The DTA and the compensating parameters were calculated by the shift of the PTV from the reference 6-dof to the 4-dof-x, y, z, and roll-optimization. In this study, the effectiveness of Tomotherapy's 4-dof bony anatomy-based autoregistration was compared with the idealized 4-dof PTV contour-based optimization. RESULTS: The maximum DTA (maxDTA) of the bony anatomy-based autoregistration was 3.2 ± 1.9 mm, with the maximum value of 8.0 mm. The maxDTA of the contour-based optimization was 1.8 ± 1.3 mm, with the maximum value of 5.7 mm. Comparison of Pearson correlation of the compensating parameters between the 2 4-dof optimization algorithms shows that there is a small but statistically significant correlation in y and z (0.236 and 0.300, respectively), whereas there is very weak correlation in x and roll (0.062 and 0.025, respectively). CONCLUSIONS: We find that there is an average improvement of approximately 1 mm in terms of maxDTA on the PTV going from 4-dof bony anatomy-based autoregistration to the 4-dof contour-based optimization. Pearson correlation analysis of the 2 4-dof optimizations suggests that uncertainties due to deformation and inadequate resolution account for much of the compensating parameters, but pitch variation also makes a statistically significant contribution.


Assuntos
Pontos de Referência Anatômicos/diagnóstico por imagem , Neoplasias da Próstata/diagnóstico por imagem , Planejamento da Radioterapia Assistida por Computador/normas , Erros de Configuração em Radioterapia/prevenção & controle , Radioterapia de Intensidade Modulada/normas , Tomografia Computadorizada Espiral/normas , Humanos , Masculino , Próstata/diagnóstico por imagem , Neoplasias da Próstata/radioterapia , Planejamento da Radioterapia Assistida por Computador/instrumentação , Radioterapia de Intensidade Modulada/instrumentação , Tomografia Computadorizada Espiral/instrumentação , Tomografia Computadorizada Espiral/métodos
16.
Int J Cardiovasc Imaging ; 28 Suppl 2: 101-7, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23099512

RESUMO

To determine the feasibility of dual-source coronary CT angiography (CTA) using a prospectively electrocardiogram (ECG)-triggered axial mode to target end-systole in patients with high heart rates (HR) as compared with the retrospective mode. One hundred fifty consecutive patients with regular HR > 75 bpm who underwent coronary CTA were enrolled; 75 patients underwent prospectively ECG-triggered coronary CTA targeting only end-systole (Prospective Axial Group) and 75 patients underwent retrospectively ECG-gated coronary CTA (Retrospective Helical Group). The image quality of multiple coronary artery segments was evaluated and radiation doses were recorded. The diagnostic performance of coronary CTA was compared to the reference standard of invasive coronary angiography in 52 patients (35 %) (28 patients in Prospective Axial Group and 24 patients in Retrospective Helical Group). Image quality was not significantly different between the 2 groups (P = 0.784). In subgroup analysis, segment-based sensitivity, specificity, and positive and negative predictive values of coronary CTA were 98, 96, 88 and 99 %, respectively, in the Prospective Axial Group and were 97, 95, 82, and 99 %, respectively, in the Retrospective Helical Group. Mean radiation dose was significantly lower for the Prospective Axial Group than for the Retrospective Helical Group (2.9 ± 1.4 vs. 7.4 ± 3.3 mSv; P < 0.0001). Dual source coronary CTA with a prospective ECG-triggered axial mode targeting end-systole is feasible in patients with regular high HRs for evaluation of coronary artery disease. It provides comparable image quality and diagnostic value with substantially lower radiation exposure as compared to the retrospective ECG-gated helical technique.


Assuntos
Técnicas de Imagem de Sincronização Cardíaca/métodos , Angiografia Coronária/métodos , Doença da Artéria Coronariana/diagnóstico por imagem , Eletrocardiografia , Frequência Cardíaca , Tomografia Computadorizada Espiral , Idoso , Técnicas de Imagem de Sincronização Cardíaca/normas , Distribuição de Qui-Quadrado , Angiografia Coronária/normas , Doença da Artéria Coronariana/fisiopatologia , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Doses de Radiação , Padrões de Referência , Sensibilidade e Especificidade , Sístole , Tomografia Computadorizada Espiral/normas
17.
Int J Radiat Oncol Biol Phys ; 84(2): 547-52, 2012 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-22365627

RESUMO

PURPOSE: To evaluate the accuracy of three-dimensional (3D) surface imaging system (AlignRT) registration algorithms for head-and-neck cancer patient setup during radiotherapy. METHODS AND MATERIALS: Eleven patients, each undergoing six repeated weekly helical computed tomography (CT) scans during treatment course (total 77 CTs including planning CT), were included in the study. Patient surface images used in AlignRT registration were not captured by the 3D cameras; instead, they were derived from skin contours from these CTs, thereby eliminating issues with immobilization masks. The results from surface registrations in AlignRT based on CT skin contours were compared to those based on bony anatomy registrations in Pinnacle(3), which was considered the gold standard. Both rigid and nonrigid types of setup errors were analyzed, and the effect of tumor shrinkage was investigated. RESULTS: The maximum registration errors in AlignRT were 0.2° for rotations and 0.7 mm for translations in all directions. The rigid alignment accuracy in the head region when applied to actual patient data was 1.1°, 0.8°, and 2.2° in rotation and 4.5, 2.7, and 2.4 mm in translation along the vertical, longitudinal, and lateral axes at 90% confidence level. The accuracy was affected by the patient's weight loss during treatment course, which was patient specific. Selectively choosing surface regions improved registration accuracy. The discrepancy for nonrigid registration was much larger at 1.9°, 2.4°, and 4.5° and 10.1, 11.9, and 6.9 mm at 90% confidence level. CONCLUSIONS: The 3D surface imaging system is capable of detecting rigid setup errors with good accuracy for head-and-neck cancer. Further investigations are needed to improve the accuracy in detecting nonrigid setup errors.


Assuntos
Algoritmos , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Planejamento da Radioterapia Assistida por Computador/métodos , Erros de Configuração em Radioterapia , Radioterapia Guiada por Imagem/métodos , Pele/diagnóstico por imagem , Tomografia Computadorizada Espiral/métodos , Análise de Variância , Pontos de Referência Anatômicos/diagnóstico por imagem , Ossos Faciais/diagnóstico por imagem , Neoplasias de Cabeça e Pescoço/patologia , Neoplasias de Cabeça e Pescoço/radioterapia , Humanos , Planejamento da Radioterapia Assistida por Computador/normas , Radioterapia Guiada por Imagem/normas , Tomografia Computadorizada Espiral/normas , Carga Tumoral
18.
Int J Cardiovasc Imaging ; 28(1): 153-62, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21153709

RESUMO

To compare image quality and radiation dose estimates for coronary computed tomography angiography (CCTA) obtained with a prospectively gated transaxial (PGT) CT technique and a retrospectively gated helical (RGH) CT technique using a 256-slice multidetector CT (MDCT) scanner and establish an upper limit of heart rate to achieve reliable diagnostic image quality using PGT. 200 patients (135 males, 65 females) with suspected coronary artery disease (CAD) underwent CCTA on a 256-slice MDCT scanner. The PGT patients were enrolled prospectively from January to June, 2009. For each PGT patient, we found the paired ones in retrospective-gating patients database and randomly selected one patient in these match cases and built up the RGH group. Image quality for all coronary segments was assessed and compared between the two groups using a 4-point scale (1: non-diagnostic; 4: excellent). Effective radiation doses were also compared. The average heart rate ± standard deviation (HR ± SD) between the two groups was not significantly different (PGT: 64.6 ± 12.9 bpm, range 45-97 bpm; RGH: 66.7 ± 10.9 bpm, range 48-97 bpm, P = 0.22). A receiver-operating characteristic (ROC) analysis determined a cutoff HR of 75 bpm up to which diagnostic image quality could be achieved using the PGT technique (P < 0.001). There were no significant differences in assessable coronary segments between the two groups for HR ≤ 75 bpm (PGT: 99.9% [961 of 962 segments]; RGH: 99.8% [1038 of 1040 segments]; P = 1.0). At HR > 75 bpm, the performance of the PGT technique was affected, resulting in a moderate reduction of percentage assessable coronary segments using this approach (PGT: 95.5% [323 of 338 segments]; RGH: 98.5% [261 of 265 segments]; P = 0.04). The mean estimated effective radiation dose for the PGT group was 3.0 ± 0.7 mSv, representing reduction of 73% compared to that of the RGH group (11.1 ± 1.6 mSv) (P < 0.001). Prospectively-gated axial coronary computed tomography using a 256-slice multidetector CT scanner with a 270 ms tube rotation time enables a significant reduction in effective radiation dose while simultaneously providing image quality comparable to the retrospectively gated helical technique. Our experience demonstrates the applicability of this technique over a wider range of heart rates (up to 75 bpm) than previously reported.


Assuntos
Técnicas de Imagem de Sincronização Cardíaca/métodos , Técnicas de Imagem de Sincronização Cardíaca/normas , Angiografia Coronária/métodos , Eletrocardiografia , Doses de Radiação , Tomografia Computadorizada Espiral/métodos , Meios de Contraste , Angiografia Coronária/normas , Doença da Artéria Coronariana/diagnóstico por imagem , Feminino , Frequência Cardíaca , Humanos , Processamento de Imagem Assistida por Computador/métodos , Iohexol , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Curva ROC , Intensificação de Imagem Radiográfica/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Reprodutibilidade dos Testes , Tomografia Computadorizada Espiral/normas
19.
Eur J Orthod ; 34(3): 276-86, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21566086

RESUMO

The aim of this study was to investigate the repeatability and reproducibility of the placement of anthropological cephalometric landmarks on three-dimensional computed tomography (3D CT) cranial reconstructions derived from volume data sets. In addition, the influence of the observer's experience on the repeatability of landmark setting was also explored. Twenty patients without any craniofacial deformity (11 females and 9 males; age range 6.1-16 years) were selected retrospectively from CT volume data sets already available from 695 patients of Dental Clinic 3, Orthodontics of Erlangen University Hospital. The CT examination was performed with the SOMATOM Sensation64 (Siemens AG Medical Solutions, Erlangen, Germany). The program VoXim6.1 (IVS Solutions AG, Chemnitz, Germany) was used for 3D reconstruction of the volume data sets. A total of 28 landmarks were examined in the skeleton module of the program VoXim6.1. The randomly sorted data sets were analysed by two orthodontists and two postgraduate students. Each data set was analysed twice by each observer at an interval of 3 weeks. The analysis of variance regarding random effects was used to calculate the intraobserver and interobserver components of standard deviation (SD) of depiction of individual landmarks as measures of repeatability and reproducibility, respectively. Median intraserial SD and interserial SD of 0.46 mm (range: 0.14-2.00 mm) and 0.20 mm (range: 0.02-2.47 mm), respectively, were obtained depending on the landmark and plane. This study included systematic analysis of extreme values (outliers) in the assessment of the quality of measurements obtained. Descriptive statistics revealed qualitative differences in the depiction of different landmarks. The landmarks nasion and infradentale revealed a minor SD in all three spatial coordinates with the smallest SD for infradentale (SD = 0.18 mm) in the transverse plane. However, no systematic trend was identified with regard to the influence of the observer's level of experience affecting the repeatability of landmark positioning. Thus, the repeatability and reproducibility of placements of landmarks with 3D CT were found to be acceptable for a majority of anatomical positions.


Assuntos
Pontos de Referência Anatômicos , Cefalometria , Má Oclusão/diagnóstico por imagem , Tomografia Computadorizada Espiral , Adolescente , Análise de Variância , Cefalometria/normas , Criança , Erros de Diagnóstico , Precisão da Medição Dimensional , Feminino , Humanos , Imagem Tridimensional , Masculino , Variações Dependentes do Observador , Reprodutibilidade dos Testes , Software , Tomografia Computadorizada Espiral/normas
20.
Acad Radiol ; 19(1): 84-8, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22142680

RESUMO

RATIONALE AND OBJECTIVES: The increasing use of computed tomography (CT) has been accompanied by rising concerns over potential radiation-related health risks, especially cancer, and a need to minimize such risks. MATERIALS AND METHODS: We conducted 2186 low-dose helical chest CT scans among 1235 nuclear weapons workers at elevated risk of lung cancer, setting the CT scanner tube current at 30 mAs for all participants with BMI <35 kg/m(2) and permitting technologists to raise mAs levels for participants with BMI ≥35 kg/m(2). Dose-length product (DLP) was recorded from the CT scanner, permitting calculation of effective dose. Phantom-based estimates of effective dose were also made. A chest radiologist recorded acceptability of image quality. RESULTS: The study population was significantly overweight: 79% exceeded a body mass index (BMI) >25 kg/m(2) and 37.1% exceeded a BMI ≥30 kg/m(2). Nearly 90% of CT scans were performed using a tube current setting of 30 mAs and had a mean DLP-based effective dose of 1.3 mSv. The phantom-based estimate of effective dose was lower at 1.1 mSv. Among participants with a BMI ≥35 kg/m(2), 92% were scanned at 40 or 50 mAs, which was associated with a DLP-based effective dose of 1.6 and 2.0 mSv, respectively. Image quality was satisfactory in 99.8% of scans. CONCLUSION: Application of simple BMI-based guidelines and DLP tracking of low-dose helical chest CT scans in a lung cancer screening program minimizes radiation dose, even in a largely overweight population.


Assuntos
Carga Corporal (Radioterapia) , Índice de Massa Corporal , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Induzidas por Radiação/diagnóstico por imagem , Proteção Radiológica/métodos , Radiometria/normas , Tomografia Computadorizada Espiral/estatística & dados numéricos , Feminino , Humanos , Neoplasias Pulmonares/epidemiologia , Pessoa de Meia-Idade , Neoplasias Induzidas por Radiação/epidemiologia , New York/epidemiologia , Armas Nucleares , Guias de Prática Clínica como Assunto , Doses de Radiação , Proteção Radiológica/normas , Proteção Radiológica/estatística & dados numéricos , Radiografia Torácica/normas , Radiografia Torácica/estatística & dados numéricos , Radiometria/estatística & dados numéricos , Tomografia Computadorizada Espiral/normas
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