RESUMO
OBJECTIVES: To assess the effect of lower volumes of contrast medium (CM) on image quality in high-pitch dual-source computed tomography coronary angiography (CTCA). METHODS: One-hundred consecutive patients (body weight 65-85 kg, stable heart rate ≤65 bpm, cardiac index ≥2.5 L/min/m(2)) referred for CTCA were prospectively enrolled. Patients were randomly assigned to one of five groups of different CM volumes (G30, 30 mL; G40, 40 mL; G50, 50 mL; G60, 60 mL; G70, 70 mL; flow rate 5 mL/s each, iodine content 370 mg/mL). Attenuation within the proximal and distal coronary artery segments was analysed. RESULTS: Mean attenuation for men and women ranged from 345.0 and 399.1 HU in G30 to 478.2 and 571.8 HU in G70. Mean attenuation values were higher in groups with higher CM volumes (P < 0.0001) and higher in women than in men (P < 0.0001). The proportions of segments with attenuation of at least 300 HU in G30, G40, G50, G60 and G70 were 89 %, 95 %, 98 %, 98 % and 99 %. CM volume of 30 mL in women and 40 mL in men proved to be sufficient to guarantee attenuation of at least 300 HU. CONCLUSIONS: In selected patients high-pitch dual-source CTCA can be performed with CM volumes of 40 mL in men or 30 mL in women. KEY POINTS: ⢠High-pitch dual-source coronary angiography is feasible with low contrast media volumes. ⢠Traditional injection rules still apply: higher volumes result in higher enhancement. ⢠The patient's gender is a co-factor determining the level of contrast enhancement. ⢠Volumes can be reduced down to 30-40 mL in selected patients.
Assuntos
Técnicas de Imagem de Sincronização Cardíaca/métodos , Meios de Contraste/administração & dosagem , Angiografia Coronária/métodos , Doença da Artéria Coronariana/diagnóstico , Tomografia Computadorizada Multidetectores/métodos , Relação Dose-Resposta a Droga , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos ProspectivosRESUMO
OBJECTIVES: To investigate image quality of triple-rule-out (TRO) computed tomography (CT) using a 320-row-detector CT system with substantially reduced contrast medium volume at 100 kV. METHODS: Forty-six consecutive patients with noncritical, acute chest pain underwent 320-row-detector CT using a two-step TRO protocol consisting of a non-spiral, non-gated chest CT acquisition (150 mA) followed by a non-spiral, electrocardiography-gated cardiac acquisition (200-500 mA based on body mass index (BMI)). Data were acquired using a biphasic injection protocol with a total iodinated contrast medium volume of 60 ml (370 mg/ml). Vessel attenuation and effective doses were recorded. Image quality was scored independently by two readers. RESULTS: Mean attenuation was 584 ± 114 Hounsfield units (HU) in the ascending aorta, 335 ± 63HU in the aortic arch, 658 ± 136HU in the pulmonary trunk, and 521 ± 97HU and 549 ± 102HU in the right and left coronary artery, respectively. In all but one patient, attenuation and image quality allowed accurate visualization of the pulmonary arteries, thoracic aorta, and coronary arteries in a single examination. Ninety-six percent of all coronary artery segments were rated diagnostic. Radiation exposure ranged between 2.0 and 3.3 mSv. CONCLUSION: Using 320-row-detector CT the investigated low-dose TRO protocol resulted in excellent opacification and image quality with substantial reduction of contrast medium volume compared to recently published TRO protocols.
Assuntos
Dor no Peito/diagnóstico por imagem , Doses de Radiação , Tomografia Computadorizada por Raios X/métodos , Índice de Massa Corporal , Meios de Contraste/administração & dosagem , Eletrocardiografia , Feminino , Humanos , Imageamento Tridimensional , Iohexol/administração & dosagem , Iohexol/análogos & derivados , Masculino , Pessoa de Meia-Idade , Interpretação de Imagem Radiográfica Assistida por ComputadorRESUMO
OBJECTIVE: To assess reduced volumes of contrast agent on image quality for coronary computed tomography angiography (CCTA) by using single-beat cardiac imaging with 320-slice CT. MATERIALS AND METHODS: Forty consecutive male patients (mean age: 55.8 years) undergoing CCTA with body weight
Assuntos
Meios de Contraste/administração & dosagem , Angiografia Coronária/métodos , Doença da Artéria Coronariana/diagnóstico por imagem , Iohexol/análogos & derivados , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Relação Dose-Resposta a Droga , Estudos de Viabilidade , Feminino , Humanos , Iohexol/administração & dosagem , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
The study investigates the effect of a substantial dose reduction on the variability of lung nodule volume measurements by assessing and comparing nodule volumes using a dedicated semiautomated segmentation software on ultralow-dose computed tomography (ULD-CT) and standard-dose computed tomography (SD-CT) data. In 20 patients, thin-slice chest CT datasets (1 mm slice thickness; 20% reconstruction overlap) were acquired at ultralow-dose (120 kV, 5 mAs) and at standard-dose (120 kV, 75 mAs), respectively, and analyzed using the segmentation software OncoTREAT (MeVis, Bremen, Germany; version 1.3). Interobserver variability of volume measurements of 202 solid pulmonary nodules (mean diameter 11 mm, range 3.2-44.5 mm) was calculated for SD-CT and ULD-CT. With respect to interobserver variability, the 95% confidence interval for the relative differences in nodule volume in the intrascan analysis was measured with -9.7% to 8.3% (mean difference -0.7%) for SD-CT and with -12.6% to 12.4% (mean difference -0.2%) for ULD-CT. In the interscan analysis, the 95% confidence intervals for the differences in nodule volume ranged with -25.1% to -23.4% and 26.2% to 28.9% (mean difference 1.4% to 2.1%) dependent on the combination of readers and scans. Intrascan interobserver variability of volume measurements was comparable for ULD-CT and SD-CT data. The calculated variability of volume measurements in the interscan analysis was similar to the data reported in the literature for CT data acquired with equal radiation dose. Thus, the evaluated segmentation software provides nodule volumetry that appears to be independent of the dose level with which the CT source dataset is acquired.
Assuntos
Neoplasias Pulmonares/diagnóstico por imagem , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Software , Nódulo Pulmonar Solitário/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Algoritmos , Automação , Intervalos de Confiança , Feminino , Humanos , Masculino , Variações Dependentes do Observador , Doses de Radiação , Estudos RetrospectivosRESUMO
We sought to determine the feasibility and image quality of 320-slice volume computed tomography (CT) angiography for the evaluation of patients with acute chest pain. Thirty consecutive patients (11 female, 19 male, mean age 63.2 +/- 14.2 years) with noncritical, acute chest pain underwent 320-slice CT using a protocol consisting of a nonspiral, nongated CT of the entire chest, followed by a nonspiral, electrocardiography-gated CT study of the heart. Data were acquired following a biphasic intravenous injection of 90 ml iodinated contrast agent. Vessel attenuation values of different thoracic vascular territories were recorded, and image quality scored on a five-point scale by two readers. Mean attenuation was 467 +/- 69 HU in the ascending aorta, 334 +/- 52 HU in the aortic arch, 455 +/- 71 HU in the descending aorta, 492 +/- 94 HU in the pulmonary trunk, and 416 +/- 63 HU and 436 +/- 62 HU in the right and left coronary artery, respectively. Radiation exposure estimates ranged between 7 and 14 mSv. The CT protocol investigated enabled imaging of the thoracic aorta, coronary and pulmonary arteries with an excellent diagnostic quality for chest pain triage in all patients. This result was achieved with less contrast material and reduced radiation exposure compared with previously investigated imaging protocols.
Assuntos
Dor no Peito/diagnóstico por imagem , Angiografia Coronária/métodos , Tomografia Computadorizada por Raios X/métodos , Idoso , Meios de Contraste/farmacologia , Diagnóstico por Imagem/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Reprodutibilidade dos Testes , Software , Tomografia Computadorizada por Raios X/instrumentação , Interface Usuário-ComputadorRESUMO
Sixty-four-slice CT typified the dramatic race in technical development in radiology. Featuring high spatial resolution with 0.5-mm thin slices and 0.3-second gantry revolution times, it has become state-of-the-art technology in CT imaging shortly after its clinical introduction. Three-dimensional tube modulation together with adaptive x-ray shutters led to significant dose reduction to the patients while improving image quality because of implementation of optimized reconstruction algorithms. The latest innovations-new detector materials, dual-layer detector, dual-source and dynamic volume CT-represent the pinnacles in CT imaging, pursuing different directions to further clinical applications of CT.
Assuntos
Tomografia Computadorizada por Raios X/métodos , Algoritmos , Artefatos , Meios de Contraste , Desenho de Equipamento , Humanos , Imageamento Tridimensional , Doses de Radiação , Intensificação de Imagem Radiográfica/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Sensibilidade e Especificidade , Avaliação da Tecnologia Biomédica , Tomógrafos ComputadorizadosRESUMO
OBJECTIVES: To evaluate gadofosveset trisodium for first-pass magnetic resonance angiography (MRA) in the setting of whole-body MRA (WB-MRA). MATERIALS AND METHODS: Forty patients were examined using either 10 mL gadofosveset trisodium (n = 20) or 30 mL gadopentetate dimeglumine (n = 20), followed by arterial-phase imaging of 4 consecutive anatomic regions. Signal intensity was measured in 2 vessels per region. Relative contrast values (RC) were calculated. Arterial contrast, venous overlay, and image quality were rated by 2 radiologists. The Mann-Whitney U test was used to test for significance. RESULTS: Compared with gadopentetate dimeglumine, gadofosveset trisodium enhanced imaging revealed higher RC values in 2 vessel regions, with the differences being significant in 3 of 4 vessel segments. Gadofosveset trisodium revealed lower RC values in 2 regions with significant differences in 2 segments. Qualitative evaluation revealed higher ratings for gadofosveset trisodium regarding all 3 criteria with significant differences in 2 regions. CONCLUSIONS: Gadofosveset trisodium serves well for first-pass imaging in WB-MRA.
Assuntos
Arteriopatias Oclusivas/diagnóstico , Gadolínio DTPA , Gadolínio , Armazenamento e Recuperação da Informação/métodos , Angiografia por Ressonância Magnética/métodos , Compostos Organometálicos , Imagem Corporal Total/métodos , Meios de Contraste , Feminino , Humanos , Aumento da Imagem/métodos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
We describe the case of a 72-year-old man presenting with endocarditis and clinical signs of acute myocardial ischemia after biological aortic valve replacement. A comprehensive cardiac dynamic multislice spiral computed tomography demonstrated: (1) an endocarditic vegetation of the aortic valve; (2) a subvalvular leakage feeding a paravalvular pseudoaneurysm based on an aortic root abscess with subsequent compromise of the systolic blood flow in the left main coronary artery and the resulting myocardial perfusion deficit.
Assuntos
Valva Aórtica/diagnóstico por imagem , Bioprótese/microbiologia , Endocardite/diagnóstico por imagem , Próteses Valvulares Cardíacas/microbiologia , Isquemia Miocárdica/diagnóstico por imagem , Infecções Estafilocócicas/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Idoso , Algoritmos , Endocardite/complicações , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Isquemia Miocárdica/etiologia , Infecções Estafilocócicas/complicaçõesRESUMO
Electron beam computed tomography (EBCT) revolutionized cardiac imaging by combining a constant high temporal resolution with prospective ECG triggering. For years, EBCT was the primary technique for some non-invasive diagnostic cardiac procedures such as calcium scoring and non-invasive angiography of the coronary arteries. Multislice spiral computed tomography (MSCT) on the other hand significantly advanced cardiac imaging through high volume coverage, improved spatial resolution and retrospective ECG gating. This pictorial review will illustrate the basic differences between both modalities with special emphasis to their image quality. Several experimental and clinical examples demonstrate the strengths and limitations of both imaging modalities in an intraindividual comparison for a broad range of diagnostic applications such as coronary artery calcium scoring, coronary angiography including stent visualization as well as functional assessment of the cardiac ventricles and valves. In general, our examples indicate that EBCT suffers from a number of shortcomings such as limited spatial resolution and a low contrast-to-noise ratio. Thus, EBCT should now only be used in selected cases where a constant high temporal resolution is a crucial issue, such as dynamic (cine) imaging. Due to isotropic submillimeter spatial resolution and retrospective data selection MSCT seems to be the non-invasive method of choice for cardiac imaging in general, and for assessment of the coronary arteries in particular. However, technical developments are still needed to further improve the temporal resolution in MSCT and to reduce the substantial radiation exposure.
Assuntos
Calcinose/diagnóstico por imagem , Angiografia Coronária/métodos , Coração/diagnóstico por imagem , Tomografia Computadorizada Espiral , Tomografia Computadorizada por Raios X , Animais , Eletrocardiografia , Humanos , Processamento de Imagem Assistida por Computador , Tomografia Computadorizada por Raios X/métodosRESUMO
PURPOSE: We selected five intraorbital tumor sites that are frequently found in clinical practice in children diagnosed with orbital rhabdomyosarcoma and performed three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated photon radiotherapy (IMRT) planning. Results of target coverage and doses to critical structures were compared. The goal of this study was to evaluate and to document realistic expectations as to organ-sparing capabilities of modern radiation therapy planning technologies with a focus on lens-sparing irradiation. Furthermore, we investigated potential added benefits of IMRT compared with 3D-CRT and the influence of protocol volume criteria definitions on the ability to obtain normal tissue dose sparing using the orbit as an example of a complex anatomic site. METHODS AND MATERIALS: The five intraorbital tumor sites were placed retrobulbar, temporal, nasal, in the upper inner and upper outer quadrant, the latter two more complex in shape. Gross tumor volume (GTV), clinical target volume (CTV), and planning target volume (PTV) were defined in image-fused computed tomography and magnetic resonance data sets. 3D-CRT and IMRT photon plans, using equal beam angles and collimation for direct comparison, were designed to 45 Gy prescription dose according to Intergroup Rhabdomyosarcoma Study Group-D9602 (IRSG-D9602) protocol (Intergroup Rhabdomyosarcoma Study V [IRS-V] protocol) for Stage I, Clinical Group 3 orbital rhabdomyosarcoma. To compare the impact of changed target definitions in IMRT planning, additional IMRT plans were generated using modified volume and dose coverage criteria. The minimum dose constraint (95%) of the PTV was substituted by a required minimum volume coverage (95%) with the prescribed dose. Dose-volume histograms (DVHs) were obtained, including target volumes, lens, optic nerves, optic chiasm, lacrimal gland, bony orbit, pituitary gland, frontal and temporal lobes. RESULTS: Protocol target volume coverage criteria were fulfilled in all cases (5/5) with 3D-CRT and IMRT. Using the protocol criteria, lens sparing was achieved only for two tumor sites (retrobulbar and lateral position) with either planning technique. Mean lens doses were 8.5 and 10.4 Gy for 3D-CRT and 7.5 and 13.2 Gy for IMRT, respectively. The mean lens doses for the other three tumor locations averaged 26.8 Gy. IMRT plans reduced the lens dose in four of five cases by an average of 2.6 Gy compared with 3D-CRT. Modified target protocol prescription markedly reduced mean lens doses by 23-50% and by as much as 18 Gy. Recorded mean lens doses after protocol modification were 26% lower using IMRT plans compared with 3D-CRT. The cold spot as a result of the relaxed volume coverage requirements was within 2% of the original protocol criteria and located at the edge of the PTV, outside the CTV. Compared with 3D-CRT, IMRT resulted in an increase of brain volume receiving 10% (V10) and 20% (V20) of the prescribed dose. CONCLUSION: Strict adherence to IRS-V protocol criteria prohibits at present lens sparing within compliance criteria for the majority of intraorbital tumor locations because of protocol-specific CTV and PTV target definitions. Changing protocol definitions by prescribing to the volume rather than to a dose constraint, IMRT planning significantly reduced lens doses. This was not accomplished to the same degree with 3D-CRT. Our study underlines the importance of appropriate selection of planning objectives to maximize the specific capabilities and advantages of IMRT in terms of sufficient target coverage and simultaneous sparing of critical structures. Our results can add to the ongoing discussion in the design of future 3D-CRT/IMRT protocols.
Assuntos
Neoplasias Orbitárias/radioterapia , Planejamento da Radioterapia Assistida por Computador/métodos , Radioterapia Conformacional/métodos , Rabdomiossarcoma/radioterapia , Criança , Humanos , Cristalino/efeitos da radiação , Imageamento por Ressonância Magnética/métodos , Lesões por Radiação/prevenção & controle , Dosagem Radioterapêutica , Tomografia Computadorizada por Raios X/métodosRESUMO
PURPOSE: The aim of our study was to correlate perfusion indices and apparent diffusion coefficients with therapy outcome after chemoradiation. METHODS AND MATERIALS: In 34 patients with primary rectal carcinoma (cT3) undergoing preoperative chemoradiation, pretherapeutic perfusion indices and apparent diffusion coefficients were obtained by dynamic or diffusion-weighted magnetic resonance imaging. Therapy response was defined if the pathologic observation revealed no invasion into the perirectal fat after chemoradiation. RESULTS: In 18 patients, a response and in 16, no response was observed. Statistically significant differences were found for the mean perfusion index (p < 0.001; 7.5 +/- 1.5 mL/min/100 g vs. 10.7 +/- 2.7 mL/min/100 g) and for the intratumoral cumulative fraction of pixels with perfusion-indices > 12 mL/min/100 g (p < 0.001, 3.7 +/- 4.0% vs. 24.7 +/- 17.9%). A three-way ANOVA resulted in significant effects for therapy responder/nonresponder (p < 0.001) and for apparent diffusion coefficient and the individual patients. CONCLUSION: Perfusion indices and apparent diffusion coefficients inside the tumor region seem to be of predictive value for therapy outcome of preoperative therapy in patients with primary rectal carcinoma. Higher parameter levels in the nonresponding group could be explained by increased shunt flow or increased angiogenic activity in aggressive tumor cell clusters resulting in reduced nutrients supply and higher fraction of intratumoral necrosis respectively.
Assuntos
Neoplasias Retais/irrigação sanguínea , Neoplasias Retais/terapia , Adulto , Idoso , Terapia Combinada , Imagem Ecoplanar , Humanos , Microcirculação , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Valor Preditivo dos Testes , Neoplasias Retais/tratamento farmacológico , Neoplasias Retais/radioterapia , Resultado do TratamentoRESUMO
BACKGROUND AND PURPOSE: Diffusion-weighted (DW) MR imaging is a means to characterize and differentiate morphologic features, including edema, necrosis, and tumor tissue, by measuring differences in apparent diffusion coefficient (ADC). We hypothesized that DW imaging has the potential to differentiate recurrent or progressive tumor growth from treatment-induced damage to brain parenchyma in high-grade gliomas after radiation therapy. METHODS: We retrospectively reviewed follow-up conventional and DW MR images obtained starting 1 month after completion of radiation treatment with or without chemotherapy for histologically proved high-grade gliomas. Eighteen patients with areas of abnormal enhancing tissue were identified. ADC maps were calculated from echo-planar DW images, and mean ADC values and ADC ratios (ADC of enhancing lesion to ADC of contralateral white matter) were compared with final diagnosis. Recurrence was established by histologic examination or by clinical course and a combination of imaging studies. RESULTS: Recurrence and nonrecurrence could be differentiated by using mean ADC values and ADC ratios. ADC ratios in the recurrence group showed significantly lower values (mean +/- SD, 1.43 +/- 0.11) than those of the nonrecurrence group (1.82 +/- 0.07, P <.001). Mean ADCs of the recurrent tumors (mean +/- SD, 1.18 +/- 0.13 x 10(-3) mm/s(2)) were significantly lower than those of the nonrecurrence group (1.40 +/- 0.17 x 10(-3) mm/s(2), P <.006). CONCLUSION: Assessment of ADC ratios of enhancing regions in the follow-up of treated high-grade gliomas is useful in differentiating radiation effects from tumor recurrence or progression.
Assuntos
Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/radioterapia , Encéfalo/efeitos da radiação , Irradiação Craniana , Imagem de Difusão por Ressonância Magnética , Glioma/diagnóstico , Glioma/radioterapia , Recidiva Local de Neoplasia/diagnóstico , Lesões por Radiação/diagnóstico , Adolescente , Adulto , Idoso , Encéfalo/patologia , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/cirurgia , Quimioterapia Adjuvante , Terapia Combinada , Diagnóstico Diferencial , Feminino , Glioma/tratamento farmacológico , Glioma/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Radioterapia Adjuvante , Estudos RetrospectivosRESUMO
PURPOSE: To evaluate the clinical value of diffusion-weighted magnetic resonance imaging (DW-MRI) to monitor response of primary carcinoma of the rectum to preoperative chemoradiation by measuring tumor apparent diffusion coefficient (ADC). MATERIALS AND METHODS: Diffusion data of nine patients undergoing preoperative combined chemoradiation for clinical staged T3, N(0-2), M(0) carcinoma of the rectum were analyzed. Diffusion-weighted echo-planar MR images were obtained prior to and at specified intervals during chemoradiation and ADCs calculated from acquired tumor images. RESULTS: Comparison of mean ADC and cumulative radiation dose showed a significant decrease of mean ADC at the 2nd (P = 0.028), 3rd (P = 0.012), and 4th (P = 0.008) weeks of treatment. Cytotoxic edema and fibrosis were considered as reasons for ADC decrease. CONCLUSION: This study demonstrated tumor ADC changes via detection of therapy-induced alterations in tumor water mobility. Our results indicate that diffusion-weighted imaging may be a valuable clinical tool to diagnose the early stage of radiation-induced fibrosis.
Assuntos
Adenocarcinoma/diagnóstico , Imagem de Difusão por Ressonância Magnética , Neoplasias Retais/diagnóstico , Adenocarcinoma/patologia , Adenocarcinoma/cirurgia , Adenocarcinoma/terapia , Adulto , Idoso , Quimioterapia Adjuvante , Fracionamento da Dose de Radiação , Imagem Ecoplanar , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Dosagem Radioterapêutica , Radioterapia Adjuvante , Neoplasias Retais/patologia , Neoplasias Retais/cirurgia , Neoplasias Retais/terapiaAssuntos
Doenças da Aorta/etiologia , Heparina/efeitos adversos , Trombocitopenia/induzido quimicamente , Trombose/etiologia , Tomografia Computadorizada por Raios X/métodos , Adulto , Doenças da Aorta/diagnóstico , Cardiomiopatias/complicações , Cardiomiopatias/tratamento farmacológico , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Trombocitopenia/complicações , Trombose/diagnósticoAssuntos
Forame Oval Patente/diagnóstico por imagem , Embolia Pulmonar/diagnóstico por imagem , Trombose/diagnóstico por imagem , Técnicas de Imagem de Sincronização Cardíaca/métodos , Forame Oval Patente/complicações , Cardiopatias/complicações , Cardiopatias/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Tomografia Computadorizada Multidetectores/métodos , Embolia Pulmonar/complicações , Trombose/complicaçõesRESUMO
OBJECTIVE: We sought to determine the comparability of multislice computed tomography (MSCT) and magnetic resonance imaging (MRI) for measuring the aortic valve orifice area (AVA) and grading aortic valve stenosis. MATERIALS AND METHODS: Twenty-seven individuals, among them 18 patients with valvular stenosis, underwent AVA planimetry by both MSCT and MRI. In the subset of patients with valvular stenosis, AVA was also calculated from transthoracic Doppler echocardiography (TTE) using the continuity equation. RESULTS: There was excellent correlation between MSCT and MRI (r = 0.99) and limits of agreement were in an acceptable range (± 0.42 cm(2)) although MSCT yielded a slightly smaller mean AVA than MRI (1.57 ± 0.83 cm(2) vs. 1.67 ± 0.98 cm(2), p < 0.05). However, in the subset of patients with valvular stenosis, the mean AVA was not different between MSCT and MRI (1.05 ± 0.30 cm(2) vs. 1.04 ± 0.39 cm(2); p > 0.05). The mean AVAs on both MSCT and MRI were systematically larger than on TTE (0.88 ± 0.28 cm(2), p < 0.001 each). Using an AVA of 1.0 cm(2) on TTE as reference, the best threshold for detecting severe-to-critical stenosis on MSCT and MRI was an AVA of 1.25 cm(2) and 1.30 cm(2), respectively, resulting in an accuracy of 96% each. CONCLUSION: Our study specifies recent reports on the suitability of MSCT for quantifying AVA. The data presented here suggest that certain methodical discrepancies of AVA measurements exist between MSCT, MRI and TTE. However, MSCT and MRI have shown excellent correlation in AVA planimetry and similar accuracy in grading aortic valve stenosis.
Assuntos
Anatomia Transversal/métodos , Estenose da Valva Aórtica/diagnóstico , Valva Aórtica/diagnóstico por imagem , Valva Aórtica/patologia , Imageamento por Ressonância Magnética/métodos , Tomografia Computadorizada Espiral/métodos , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
PURPOSE: We sought to compare the performance of 3 computer-aided detection (CAD) polyp algorithms in computed tomography colonography (CTC) with fecal tagging. METHODS: CTC data sets of 33 patients were retrospectively analysed by 3 different CAD systems: system 1, MedicSight; system 2, Colon CAD; and system 3, Polyp Enhanced View. The polyp database comprised 53 lesions, including 6 cases of colorectal cancer, and was established by consensus reading and comparison with colonoscopy. Lesions ranged from 6-40 mm, with 25 lesions larger than 10 mm in size. Detection and false-positive (FP) rates were calculated. RESULTS: CAD systems 1 and 2 could be set to have varying sensitivities with higher FP rates for higher sensitivity levels. Sensitivities for system 1 ranged from 73%-94% for all lesions (78%-100% for lesions > or =10 mm) and, for system 2, from 64%-94% (78%-100% for lesions > or =10 mm). System 3 reached an overall sensitivity of 76% (100% for lesions > or =10 mm). The mean FP rate per patient ranged from 8-32 for system 1, from 1-8 for system 2, and was 5 for system 3. At the highest sensitivity level for all polyps (94%), system 2 showed a statistically significant lower FP rate compared with system 1 (P = .001). When analysing lesions > or =10 mm, system 3 had significantly fewer FPs than systems 1 and 2 (P < .012). CONCLUSIONS: Standalone CTC-CAD analysis in the selected patient collective showed the 3 systems tested to have a variable but overall promising performance with respect to sensitivity and the FP rate.
Assuntos
Algoritmos , Pólipos do Colo/diagnóstico por imagem , Colonografia Tomográfica Computadorizada/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Idoso , Idoso de 80 Anos ou mais , Meios de Contraste , Reações Falso-Positivas , Fezes , Feminino , Humanos , Iohexol/análogos & derivados , Masculino , Pessoa de Meia-Idade , Interpretação de Imagem Radiográfica Assistida por Computador/instrumentação , Estudos Retrospectivos , Sensibilidade e Especificidade , Irrigação Terapêutica/métodosRESUMO
OBJECTIVES: To compare the intra- and interobserver variability of diameter and semiautomated volume measurements of brain metastases on contrast-enhanced magnetic resonance imaging (CE-MRI) data. MATERIALS AND METHODS: About 75 MRI staging examinations of patients with metastasized renal cell carcinoma, thyroid cancer, or malignant melanoma (mean age, 56 years; range, 40-75 years) were included. Patients had been examined with a routine MRI protocol, including a CE 3D T1-weighted MP-RAGE sequence (1-mm slice thickness). MRI data were retrospectively analyzed using the OncoTREAT segmentation system (MeVis, Bremen, Germany, version 1.6). Volume of 355 enhancing brain metastases included in the analysis as well as the largest diameter according to Response Evaluation Criteria for Solid Tumors were measured by 2 radiologists. Intra- and interobserver variability was calculated. RESULTS: Metastases (n = 355) had a mean diameter of 12.2 mm (range, 3.4-44.3 mm) and a mean volume of 1.4 cm(3) (range, 12-25.1 cm(3)). With respect to interobserver variability analysis revealed broader limits of agreement for response evaluation criteria for solid tumor measurements of all lesions (range, +/-27.8%-+/-33.0%; unsigned mean: 0.2%-2.5%) than for volume measurements (range, +/-21.4%-+/-23.3%; unsigned mean, 0.1%-0.3%) with statistically significant differences between diameter and volume measurements (P Assuntos
Neoplasias Encefálicas/diagnóstico por imagem
, Neoplasias Encefálicas/secundário
, Meios de Contraste
, Imageamento por Ressonância Magnética/métodos
, Adulto
, Idoso
, Neoplasias Encefálicas/patologia
, Meios de Contraste/administração & dosagem
, Humanos
, Processamento de Imagem Assistida por Computador
, Pessoa de Meia-Idade
, Estadiamento de Neoplasias
, Variações Dependentes do Observador
, Radiografia
, Carga Tumoral
RESUMO
OBJECTIVES: We sought to evaluate the accuracy of multislice computed tomography (MSCT) with 64 detector rows for determination of the aortic valve area (AVA) compared with transesophageal and transthoracic echocardiography (TEE and TTE) and cardiac catheterization (CATH). MATERIALS AND METHODS: MSCT, TEE, TTE, and CATH were performed in 36 patients with aortic valve stenosis. AVA was determined by planimetry on MSCT and TEE and calculated using the continuity equation on Doppler TTE and the Gorlin formula on CATH. RESULTS: The mean AVA on MSCT (0.88 +/- 0.39 cm2) was not significantly different from TEE (0.94 +/- 0.41 cm2; P > 0.05) but significantly larger than TTE (0.74 +/- 0.28 cm2; P < 0.001) and CATH (0.75 +/- 0.31 cm2; P < 0.001). A good correlation with acceptable limits of agreement was found between MSCT and TTE (r = 0.91, limits +/-0.35 cm2) and between MSCT and CATH (r = 0.91, limits +/-0.32 cm2). An inferior correlation with wider limits of agreement was found between MSCT and TEE (r = 0.82, limits +/-0.48 cm2), but this applied also between TEE and TTE (r = 0.79, limits +/-0.51 cm2) and between TEE and CATH (r = 0.78, limits +/-0.52 cm2). CONCLUSIONS: AVA determined by MSCT correlated well with TTE and CATH, but a systematic difference must be taken into account when using MSCT findings for therapeutic decision-making. Validation against both TTE and CATH revealed a superior correlation and narrower limits of agreement for MSCT than for TEE suggesting that AVA planimetry with MSCT is more reliable than with TEE.
Assuntos
Estenose da Valva Aórtica/diagnóstico , Cateterismo Cardíaco/métodos , Ecocardiografia/métodos , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Tomografia Computadorizada Espiral/métodos , Idoso , Ecocardiografia Transesofagiana/métodos , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
OBJECTIVE: To evaluate soft tissue contrast and image quality of a respiratory-triggered echo-planar imaging based diffusion-weighted sequence (EPI-DWI) with different b values for magnetic resonance imaging (MRI) of the liver. METHODS: Forty patients were examined. Quantitative and qualitative evaluation of contrast was performed. Severity of artifacts and overall image quality in comparison with a T2w turbo spin-echo (T2-TSE) sequence were scored. RESULTS: The liver-spleen contrast was significantly higher (P < 0.05) for the EPI-DWI compared with the T2-TSE sequence (0.47 +/- 0.11 (b50); 0.48 +/- 0.13 (b300); 0.47 +/- 0.13 (b600) vs 0.38 +/- 0.11). Liver-lesion contrast strongly depends on the b value of the DWI sequence and decreased with higher b values (b50, 0.47 +/- 0.19; b300, 0.40 +/- 0.20; b600, 0.28 +/- 0.23). Severity of artifacts and overall image quality were comparable to the T2-TSE sequence when using a low b value (P > 0.05), artifacts increased and image quality decreased with higher b values (P < 0.05). CONCLUSION: Respiratory-triggered EPI-DWI of the liver is feasible because good image quality and favorable soft tissue contrast can be achieved.