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Hiroto Hatabu

Publications and source records attributed to Hiroto Hatabu.

At least 19 recordsLinked to original sources
PubMed2007

Assessment of bolus injection protocol with appropriate concentration for quantitative assessment of pulmonary perfusion by dynamic contrast-enhanced MR imaging.

PURPOSE: To determine the appropriate concentration for quantitative assessment of dynamic contrast-enhanced pulmonary MR imaging. MATERIALS AND METHODS: A total of 40 consecutive patients with small bronchioalveolar carcinoma underwent perfusion single-photon emission tomography (SPECT) and three-dimensional (3D) dynamic MR imaging with a 3D radiofrequency spoiled gradient-echo sequence. In each patient, 5 mL of contrast media with 0.1, 0.3, and 0.5 mmol/mL were administered at a rate of 5 mL/second. All patients were divided into two groups (<70 kg and > or =70 kg) for assessment of appropriate concentration to quantitatively assess regional perfusion parameter in routine clinical practice. Pulmonary blood flow (PBF) in each protocol was calculated from a signal intensity (SI)-time course curve. Differences and limits of agreement of PBF between dynamic MR imaging (PBF(MR)) using three different concentrations and perfusion SPECT (PBF(SPECT)) were statistically compared in both patient groups. RESULTS: PBF(MR) using 0.3 mmol/mL in the <70-kg group and 0.5 mmol/mL in the > or =70-kg group showed no significant difference compared with PBF(SPECT) (P > 0.05). Limits of agreements in 0.3 mmol/mL in the <70-kg group and 0.5 mmol/mL in the > or =70-kg group were smaller than those of the other concentrations and small enough for clinical purposes. CONCLUSION: Appropriate concentrations provide accurate and reproducible assessments of regional pulmonary perfusion parameters on 3D dynamic MR perfusion imaging. We suggest using 5 mL of contrast media with 0.3 mmol/mL for patients weighing less than 70 kg and 0.5 mmol/mL for patients weighing 70 kg or more.

Aged↗
PubMed2007

Primary pulmonary hypertension: 3D dynamic perfusion MRI for quantitative analysis of regional pulmonary perfusion.

OBJECTIVE: The purpose of this study was to determine whether quantitative pulmonary perfusion parameters obtained from 3D dynamic contrast-enhanced MR perfusion data can be used to assess the severity of primary pulmonary hypertension (PPH) as indicated by pulmonary vascular resistance (PVR) and mean pulmonary artery pressure (MPAP). CONCLUSION: Three-dimensional dynamic contrast-enhanced MRI has potential for assessment of disease severity as indicated by PVR and MPAP in patients with PPH.

Adult↗
PubMed2006

Quantitative analysis of the velocity and synchronicity of diaphragmatic motion: dynamic MRI in different postures.

The objectives of this study were to assess the relationship between right and left hemidiaphragmatic motions during breathing in normal subjects and to investigate alterations in lung motion with changes in posture, using dynamic magnetic resonance (MR) imaging. Imaging was conducted with a 1.5-T MR scanner using fast imaging employing steady-state acquisition with a torso coil. Eight healthy subjects were instructed to breathe from end-inspiration to end-expiration as slowly and as deeply as possible. Imaging and breathing were started together to afford sequential images on the coronal plane. Imaging sequences were performed in supine, prone, left lateral decubitus and right lateral decubitus postures. The component of movement of the most cephalic point in the cephalocaudal axis was measured, and the diaphragmatic excursion (maximum hemidiaphragmatic displacement), synchrony and velocity of the right and left hemidiaphragmatic motions were calculated during the expiratory phase and the inspiratory phase, respectively. Excursion was greater in the right hemidiaphragm in most postures, except the left lateral decubitus. In supine and prone postures, both hemidiaphragms moved synchronously in both inspiratory and expiratory phases. In both lateral decubitus postures, the hemidiaphragms moved asynchronously with different velocities in the expiratory phase but with the same velocities in the inspiratory phase. The method described here allowed the assessment of diaphragmatic motions. Motions in the right and left hemidiaphragms changed with posture. In addition, diaphragmatic motion differed between expiratory and inspiratory phases. This study suggests the further potential of dynamic MR imaging for the evaluation of pulmonary functions or deficiencies.

Adult↗
PubMed2006

Coronal reformations of the chest on 64-row multi-detector row CT: evaluation of image quality in comparison with 16-, 8- and 4-row multi-detector row CT.

PURPOSE: To evaluate image quality of coronal reformations of chest performed on 64-row MDCT in comparison with 16-, 8- and 4-row MDCT. MATERIALS AND METHODS: Consecutive patients who underwent pulmonary CT angiography using four different MDCT scanners were retrospectively studied with IRB approval: (1) n=30, 64-row MDCT; (2) n=30, 16-row MDCT; (3) n=30, 8-row MDCT; (4) n=30, 4-row MDCT. Coronal reformatted images (2 mm thickness and 2mm intervals for 64-row MDCT; 5 mm thickness and 5 mm intervals for 16-, 8- and 4-row MDCT) were evaluated by consensus reading of two board-certified radiologists who were blinded to scanner type. The image quality of overall chest appearance and individual thoracic structures including heart, aorta and pulmonary arteries was graded using five-point scale. Grades from four different scanners were compared using Kruskal-Wallis test. A second evaluation was performed in 48 randomly selected patients (12 patients for each scanner). Reproducibility was assessed using weighted-kappa analysis. RESULT: Significant reproducibility was observed between the first and second evaluations in 48 patients both for image quality of overall chest (weighted kappa=0.826) and each thoracic structure (mean weighted kappa=0.803; range, 0.729-0.858). Image quality of overall chest and individual thoracic structures differed significantly among four different MDCT groups, with 64-row MDCT having the highest grades, followed by 16-, 8- and 4-row MDCT (mean grades for overall chest in each scanner: 3.9, 3.0, 2.4 and 1.9, respectively) (P<0.0001 for overall chest and each thoracic structure). CONCLUSION: When comparing coronal reformations of chest using four different MDCT scanners, the 64-row MDCT had the highest image quality for overall chest appearance and individual thoracic structures, followed by 16-, 8- and finally 4-row MDCT.

Adult↗
PubMed2006

Pulmonary nodule detection in CT images with quantized convergence index filter.

A novel filter termed quantized convergence index filter (QCI filter) that is capable of enhancing the conspicuity of rounded lesions is proposed as part of a CAD (computer-aided diagnosis) scheme for detecting pulmonary nodules in computed tomography (CT) images. In this filter and its predecessor, the convergence index filter (CI filter), the output at a pixel represents the degree of convergence toward the pixel shown by the directions of gray-level gradients at surrounding pixels. The QCI filter and the CAD scheme were evaluated using five clinical datasets containing 50 nodules. With the support region of 9 x 9 pixels, the QCI filter showed more selective response to the nodules than the CI filter. In the CAD scheme, intermediate nodule candidates are generated based on the QCI filter output and then classified using linear discriminant analysis of eight features that are attributed to each intermediate nodule candidate. The QCI filter output level itself was used as one of the features. The scheme achieved a sensitivity of 90% with 1.67 false positives per slice. The QCI filter output level was most effective among the features in correctly classifying intermediate nodule candidates. The QCI filter is promising as a tool of preprocessing for automated pulmonary nodule detection in CT images.

Algorithms↗
PubMed2006

Evaluation of thoracic abnormalities on 64-row multi-detector row CT: comparison between axial images versus coronal reformations.

PURPOSE: To evaluate the capability of coronal reformations of chest on 64-row MDCT in demonstrating thoracic abnormalities in comparison with axial images. MATERIALS AND METHODS: Thirty-eight consecutive patients who underwent pulmonary CTA on 64-row MDCT were retrospectively studied with institutional review board (IRB) approval. Contiguous 2 mm axial and coronal images were reviewed independently with a 1-week interval, by consensus reading of two board-certified radiologists. Overall image quality was graded using a five-point scale. Abnormalities in mediastinum, hilum, pulmonary vessels, aorta, heart, esophagus, pleura, chest wall, and lung parenchyma were scored: 1 = definitely absent, 2 = probably absent, 3 = equivocal, 4 = probably present, 5 = definitely present. Scores on axial and coronal images were compared using weighted kappa analysis. RESULTS: Overall image quality was not different with statistical relevance between axial and coronal images (mean/median scores; 3.7/4; 3.6/4, respectively, P = 0.286, Wilcoxon signed-rank test). Significant agreement was observed between axial and coronal scores (mean weighted kappa, 0.661; range, 0.362-1). Agreement was almost perfect for pneumothorax, lung and pleural mass, effusion and consolidation (weighted kappa=0.833-1); substantial for pulmonary embolism, trachea, mediastinal lymphadenopathy and non-skeletal chest wall lesion, heart, esophagus, and emphysema (weighted kappa, 0.618-0.799); moderate for atelectasis, mediastinum, hilar nodes, aorta, other lung lesions, skeletal chest wall lesions, linear scarring, nodules > 1 cm, pulmonary artery abnormalities and pleural thickening (weighted kappa, 0.405-0.592); and fair for nodules < 1 cm (weighted kappa = 0.362). CONCLUSION: Coronal reformations on 64-row MDCT had substantial agreement with axial images for evaluation of the majority of thoracic abnormalities.

Adult↗
PubMed2006

Loss of anteroposterior intralobar attenuation gradient of the lung: Correlation with pulmonary function.

RATIONALE AND OBJECTIVES: Since the initial description of an intralobar attenuation gradient by Webb et al, it has been suggested that departure from the intralobar attenuation gradient could indicate early lung diseases. However, its significance has not been determined in detail. We aimed to quantify the anteroposterior intralobar attenuation gradient on volumetric end-inspiratory and end-expiratory high-resolution computed tomography (CT) in patients with emphysema and to correlate the gradient values with pulmonary function. MATERIALS AND METHODS: The study population consisted of 21 consecutive patients with emphysema evaluated with volumetric expiratory high-resolution CT and 6 patients with normal high-resolution CT findings. The anteroposterior intralobar attenuation gradient values were quantified on end-inspiratory and end-expiratory sagittal reformations using a lung analysis software program and were correlated with pulmonary function tests results. RESULTS: The intralobar attenuation gradient values in patients with forced expiratory volume in 1 second (FEV1) < or =70% were significantly smaller compared with those in patients with FEV1 >70% in bilateral lower lobes at end-expiration (P = .0061, P = .047, respectively, unpaired t-test). The FEV1 values in patients with attenuation gradient values < or =0.02 were significantly lower than in those with attenuation gradient values >0.02 (right lower lobe: P = .024; left lower lobe: P = .0034; chi-squared test). The intralobar attenuation gradient values in bilateral lower lobes at end-expiration were significantly correlated with FEV1 and FEV1/forced vital capacity (right: P = .031, P = .039, respectively; left: P = .036, P = .030, respectively, Pearson correlation). CONCLUSIONS: The quantitative measurement of the anteroposterior intralobar attenuation gradient values of the lung showed that these gradients at end-expiration in both lower lobes correlate with obstructive physiology.

Adult↗
PubMed2006

Correlation between image noise and body weight in coronary CTA with 16-row MDCT.

RATIONALE AND OBJECTIVES: To evaluate the correlation between image noise and body weight (BW) or body mass index (BMI) in coronary computed tomography angiography (CTA) as a potential parameter for reducing radiation dose in coronary CTA. MATERIALS AND METHODS: Thirty-six patients who underwent electrocardiogram-gated cardiac CT were analyzed in this study. The patients included 26 men and 10 women with a mean age of 60 years (range 43-79 years). All patients were imaged on a 16-row multidetector CT scanner. Mean value of BW and BMI was 83.5 kg and 28.1, respectively. Image noise was defined as standard deviation (SD) of the attenuation values measured by using 1 cm2 circular region of interest in the ascending aorta at the level of the right main pulmonary artery. The SD values were plotted against BW and BMI. The correlations were examined using a linear regression method. A P value of less than .05 was considered significant. RESULTS: The r value of linear regression between noise and BW was 0.90 (P < .001). The r value of linear regression between noise and BMI was 0.74 (P = .015). CONCLUSIONS: Excellent correlation was observed between noise and BW in coronary CTA. These data may be used as potential parameters for customized radiation dose modification to reduce radiation dose in coronary CT examinations.

Adult↗
PubMed2006

Incidence of pulmonary embolism in younger versus older patients using CT.

OBJECTIVE: The aim of this study is to compare the incidence of pulmonary embolism (PE) on computed tomography (CT) studies between younger and older patients to determine if there is an age-related bias for overutilization of CT pulmonary angiography (CTPA) in younger patients. MATERIAL AND METHODS: Six hundred thirty-one consecutive CTPA cases for suspected acute PE between 11/10/2003 and 3/19/2004 were retrospectively studied. Of these 631 cases, 59 patients were found to have clots in the pulmonary arteries (ranging from central to subsegmental PA). CTPA was performed using multidetector CT at 1.25-mm collimation, 120 kVp, 320 mA. Patients were categorized by gender and age: A, less than 20 (n = 11); B, 20 to 29 (n = 44); C, 30 to 39 (n = 59); D, 40 to 49 (n = 90); E, 50 to 59 (n = 120); F, 60 to 69 (n = 114); G, 70 to 79 (n = 104); H, 80 to 89 (n = 72); I, 90 or more (n = 21). The incidences of PE were calculated in each gender and age group. To compare the incidence of PE between younger and older groups, they were divided into 2 groups at the ages of 40 (<39 and > or = 40), 50 (<49 and > or = 50), and 60 (<59 and > or = 60). Statistical analysis was performed using the chi test. RESULTS: The incidences of PE were 11.9% in males (A, 0%; B, 17.6%; C, 10%; D, 8.3%; E, 13.3%; F, 6.9%; G, 17.5%; H, 23.5%; I, 0%), 7.7% in females (A, 0%; B, 7.4%; C, 5.1%; D, 12.5%; E, 4.2%; F, 14.5%; G, 7.8%; H, 5.5%; I, 0%), and 9.4% in total patients (A, 0%; B, 11.1%; C, 6.8%; D, 11.1%; E, 7.5%; F, 10.5%; G, 11.5%; H, 9.7%; I, 0%). No significant differences in the incidences of PE were observed when patients were divided at the age of 40 (male, female, total; P=1.0, 0.6252, 0.7220), at the age of 50 (male, female, total; P = 0.6748, 0.6879, 1.0), or at the age of 60 (male, female, total; P = 0.8458, 0.7046, 0.6820). CONCLUSION: No statistically significant difference in the incidence of PE was observed between younger and older patients. Our findings suggest that there is no age-related bias for overutilization of CT angiography (CTA) in younger patients.

Adolescent↗
PubMed2006

Fetal lung volume measurements: determination with MR imaging--effect of various factors.

PURPOSE: To retrospectively determine the effect of gestational age (GA), imaging plane, section thickness, and inter- and intraobserver variability on fetal lung volume (FLV) measurements obtained with magnetic resonance (MR) imaging in a cohort of fetuses without thoracic abnormalities. MATERIALS AND METHODS: Institutional review board approval was obtained. Informed consent for this retrospective cohort study was waived, and the conduct of this study was HIPAA compliant. FLV was measured in 30 fetuses (GA, 17-36 weeks) referred for MR imaging for indications other than pulmonary abnormalities. Measurements were made on single-shot fast spin-echo images by tracing free-form regions of interest on individual consecutive sections in the transverse, sagittal, and coronal planes. Measurements were performed twice by two observers independently. Correlations between FLV and GA, imaging plane, and section thickness were assessed, as were intra- and interobserver variability. Time to perform FLV was assessed in a subset of fetuses. RESULTS: Total FLV ranged from 2 to 110 mL. Mixed-effects regression model showed significant quadratic trend in FLV with increasing GA, with comparable strength of correlation (r = 0.89-0.91) in the three imaging planes of measurement. Intraobserver agreement was good in all three planes (r = 0.65-0.83) and was highest in the transverse plane. Interobserver agreement was good in all three planes (r = 0.68-0.76). FLV showed no significant dependence on section thickness (P = .23) or imaging plane (P = .82). Mean time to obtain FLV measurements ranged from 48 seconds at GA of 21 weeks to 77 seconds at GA of 29-30 weeks. CONCLUSION: GA-based FLV measurements obtained with MR images are independent of section thickness and imaging plane and can be performed with good inter- and intraobserver agreement in less than 2 minutes.

Female↗
PubMed2005

Lung cancer detected in patients presenting to the Emergency Department studies for suspected pulmonary embolism on computed tomography pulmonary angiography.

PURPOSE: To study the frequency and demographics of lung cancer on CT pulmonary angiography in patients with suspected pulmonary embolism referred from the Emergency Department. MATERIALS AND METHODS: Retrospective review of the medical records and radiology reports, clinical and imaging follow-up studies and pathological reports revealed 1106 CT pulmonary angiography studies referred from our Emergency Department during the 15-month period between March 2003 and June 2004. RESULTS: Five incidental lung cancer cases were found in 1106 studies from 1081 patients (0.47%). Pulmonary embolism was found in 95 patients (8.5%). Among the five incidental cases three patients were female and two were male (62-81 years old; mean 73 years, 17-130 packs year; mean 51 packs year). Tumor size ranged from 1.8 to 4.5 cm (mean 3.3 cm). The stagings of the lung cancers were IIIB in one patient and IV in four patients. CONCLUSION: Previously undiagnosed lung cancer was detected in 0.45% of patients among 1081 patients referred from Emergency Department, one of whom had coexistent pulmonary embolism. All five patients presented at advanced lung cancer stages of IIIB and IV.

Aged↗
PubMed2005

Oxygen-enhanced MR imaging: correlation with postsurgical lung function in patients with lung cancer.

PURPOSE: To prospectively determine if lung function as assessed with oxygen-enhanced magnetic resonance (MR) imaging correlates with postsurgical lung function in patients with lung cancer, as compared with quantitative and qualitative findings of computed tomography (CT) and scintigraphy. MATERIALS AND METHODS: Study received institutional review board approval, and informed patient consent was obtained. Thirty consecutive patients (16 men and 14 women, aged 44-81 years; mean age, 65 years) considered candidates for lung resection underwent oxygen-enhanced MR imaging, CT, perfusion scintigraphy, and measurement of forced expiratory volume in 1 second (FEV1). A respiratory-synchronized inversion-recovery half-Fourier single-shot turbo spin-echo MR sequence was used for data acquisition. Correlation of postsurgical lung function (postsurgical FEV1) as determined with oxygen-enhanced MR imaging (FEV1MR), quantitative assessment with CT (FEV1Quant), qualitative assessment with CT (FEV1Qual), and perfusion scintigraphy (FEV1PS) was conducted with actual postsurgical FEV1, and the limits of agreement of each were determined with Bland-Altman analysis. RESULTS: Correlation between postsurgical FEV1MR and actual postsurgical FEV1 values was excellent (r2= 0.81, P < .001); it was better than that of FEV1Qual (r2= 0.76) and FEV1PS (r2= 0.77) and similar to that of FEV1Quant (r2= 0.81) values. The limits of agreement of FEV1MR were between -9.9% and 10.9%. CONCLUSION: Oxygen-enhanced MR imaging can be used to predict posturgical lung function in patients with lung cancer, similar to quantitative CT.

Adult↗
PubMed2005

Tracheobronchomalacia: comparison between end-expiratory and dynamic expiratory CT for evaluation of central airway collapse.

PURPOSE: To compare dynamic expiratory and end-expiratory computed tomography (CT) for depicting central airway collapse in patients with acquired tracheobronchomalacia (TBM). MATERIALS AND METHODS: Institutional review board approval was obtained, and informed consent was not needed. Retrospective review was performed of all patients with a CT diagnosis of TBM in a 10-month period (n = 34) who underwent evaluation of airway disease by means of three different sequences at multi-detector row CT: end inspiration, dynamic expiration, and end expiration (the latter was performed only at the levels of the aortic arch, carina, and bronchus intermedius). Fourteen patients (11 men, three women; age range, 19-79 years) who had comparable images obtained with all three sequences at any of these three levels were included in the study. The degree of airway collapse was measured by two thoracic radiologists in consensus by calculating the percentage change in the area of the airway between inspiratory and expiratory scanning. Statistical analysis was performed by using the paired t test. RESULTS: Dynamic expiratory CT elicited a significantly greater degree of airway collapse than end-expiratory CT at all three levels (P < .005). The mean percentages of airway collapse at each of the three levels were as follows: aortic arch, 53.9% with dynamic expiration versus 35.7% with end expiration (P = .0046); carina, 53.6% with dynamic expiration versus 30.9% with end expiration (P < .0001); and bronchus intermedius, 57.5% with dynamic expiration versus 28.6% with end expiration (P = .0022). CONCLUSION: Dynamic expiratory CT elicits a significantly greater degree of airway collapse than standard end-expiratory CT in patients with TBM.

Adult↗
PubMed2005

Prognostic value of dynamic MR imaging for non-small-cell lung cancer patients after chemoradiotherapy.

PURPOSE: To determine the prognostic value of dynamic MRI for non-small-cell lung cancer (NSCLC) patients after chemoradiotherapy. MATERIALS AND METHODS: A total of 114 consecutive patients with NSCLC underwent dynamic MRI after chemoradiotherapy. The patients were divided into two groups (local control (n=22) and local failure (n=92)) according to the presence of local recurrence. From the signal intensity-time course curve in each subject, the maximum relative enhancement ratio and slope of enhancement were calculated, and compared between two groups by Student's t-test. To determine the feasible threshold values of both MR indexes for group differentiation, ROC-based positive tests were performed. Finally, the Kaplan-Meier survival curves of each group divided by the adapted threshold value were compared by log-rank test. RESULTS: The maximum relative enhancement ratio and the slope of enhancement in the local control group were significantly lower than those in the local failure group (P<0.05). Using 0.08/sec as the threshold value of the slope of enhancement, the sensitivity and specificity for differentiation between the two groups were 90.9% and 91.3%, respectively. When the slope of enhancement was adopted for estimation of prognosis after therapy, the mean survival period of the slope of enhancement 0.08/sec (P<0.0001). CONCLUSION: Dynamic MRI has potential prognostic value for NSCLC patients after chemoradiotherapy.

Adult↗
PubMed2005

Bronchomalacia in sarcoidosis: evaluation on volumetric expiratory high-resolution CT of the lung.

RATIONALE AND OBJECTIVES: The aim of this study is to investigate the frequency of bronchomalacia associated with sarcoidosis and compare the extent of air trapping in patients with sarcoidosis with and without bronchomalacia. MATERIALS AND METHODS: Eighteen consecutive patients (6 men, 12 women; age, 29-64 years; mean age, 47 years) with pathologically proven sarcoidosis who underwent clinical volumetric expiratory high-resolution computed tomography were studied. On contiguous end-expiratory images, the presence and severity of bronchomalacia and extent of air trapping were evaluated. The extent of air trapping was compared between patients with sarcoidosis with and without bronchomalacia. RESULTS: Bronchomalacia was noted in 11 of 18 patients (61%) with sarcoidosis (grade 1 [mild], n = 6; grade 2 [moderate], n = 4; and grade 3 [severe], n = 1). Air trapping was observed in 17 of 18 patients (94%; grade 1 [1%-25%], n = 8; grade 2 [26%-50%], n = 9). The extent of air trapping in patients with bronchomalacia was significantly greater than that in patients without bronchomalacia (P = .027, chi-squared test). CONCLUSION: Bronchomalacia frequently was associated with sarcoidosis, and the extent of air trapping was significantly greater in patients with sarcoidosis with bronchomalacia compared with those without bronchomalacia.

Adult↗
PubMed2005

Comparison of artifacts on coronal reformation and axial CT pulmonary angiography images using single-detector and 4- and 8-detector multidetector-row helical CT scanners.

RATIONALE AND OBJECTIVES: The aim of this study is to compare the degree of stair-step artifact on coronal reformation computed tomographic (CT) pulmonary angiography images obtained using single-detector helical CT (SDCT), four-detector (4-MDCT), and eight-detector multidetector-row CT (8-MDCT) and compare the degree of motion artifact on the corresponding axial CT images. MATERIALS AND METHODS: Three groups of consecutive patients imaged by means of CT angiography for suspected pulmonary embolus were retrospectively identified by using CT records at our institution: (1) group A (n = 38), SDCT; (2) group B (n = 36), 4-MDCT; and (3) group C (n = 74), 8-MDCT. For each case, coronal multiplanar volume reformation maximal intensity projection images were created by using a standard technique. All images were reviewed in a randomized fashion by two thoracic radiologists who were blinded to the type of CT scanner. Stair-step artifact of pulmonary arteries on coronal reformation images was graded by consensus agreement using a four-point scale (0 = no artifact to 3 = severe artifact). Axial images were assessed for six parameters of motion artifact. The sum of these grades resulted in a total motion score, with a potential range of 0 (no motion) to 12 (severe motion). Statistical analysis was performed using the Mann-Whitney test. RESULTS: Stair-step artifacts were significantly higher for SDCT (mean, 2.9; median, 3) compared with 4-MDCT (mean, 2.2; median, 2; P < .0001) and 8-MDCT (mean, 1.5; median, 1; P < .0001). Total motion scores were significantly higher for SDCT (mean, 9.3) compared with 4-MDCT (mean, 8.4; P = .03) and 8-MDCT (mean, 6.8; P < .0001). CONCLUSION: Stair-step artifacts are significantly higher with SDCT compared with MDCT. For MDCT, eight-detector scanners produce images with significantly less artifact than four-detector scanners.

Adolescent↗
PubMed2005

Functional evaluation of the postoperative gastrointestinal tract using kinematic MR imaging: Quantitative assessment of peristaltic activity.

The purpose of this study is to demonstrate the feasibility of kinematic MR imaging in visualizing peristaltic activity in the reconstructed gastrointestinal tract with quantitative measurements. Sixteen patients with gastrointestinal reconstruction were studied with kinematic MR imaging using HASTE and/or true FISP. Peristaltic waves were noted in the retrosternal gastric segment after gastric pull through (frequency = 3.0 +/- 0.5 times/min, velocity = 2.6 +/- 0.6 mm/s) and in the residual antrum after cardiectomy (frequency = 3 times/min, velocity = 4.0 mm/s). Peristaltic waves were not apparent in the residual fundus after distal gastrectomy and in the reconstructed jejunum after pancreatoduodenectomy and gastrojejunostomy.

Aged↗