Biomedical subjects

Katsuhide Ito

Publications and source records attributed to Katsuhide Ito.

At least 19 recordsLinked to original sources

PubMed2006

CT appearance of radiation injury of the lung and clinical symptoms after stereotactic body radiation therapy (SBRT) for lung cancers: are patients with pulmonary emphysema also candidates for SBRT for lung cancers?

PURPOSE: The purpose of this study was to analyze the computed tomographic (CT) appearance of radiation injury to the lung and clinical symptoms after stereotactic body radiation therapy (SBRT) and evaluate the difference by the presence of pulmonary emphysema (PE) for small lung cancers. METHODS AND MATERIALS: In this analysis, 45 patients with 52 primary or metastatic lung cancers were enrolled. We evaluated the CT appearance of acute radiation pneumonitis (within 6 months) and radiation fibrosis (after 6 months) after SBRT. Clinical symptoms were evaluated by Common Terminology Criteria for Adverse Events, version 3.0. We also evaluated the relationship between CT appearance, clinical symptoms, and PE. RESULTS: CT appearance of acute radiation pneumonitis was classified as follows: (1) diffuse consolidation, 38.5%; (2) patchy consolidation and ground-glass opacities (GGO), 15.4%; (3) diffuse GGO, 11.5%; (4) patchy GGO, 2.0%; (5) no evidence of increasing density, 32.6%. CT appearance of radiation fibrosis was classified as follows: (1) modified conventional pattern, 61.5%; (2) mass-like pattern, 17.3%; (3) scar-like pattern, 21.2%. Patients who were diagnosed with more than Grade 2 pneumonitis showed significantly less no evidence of increased density pattern and scar-like pattern than any other pattern (p=0.0314, 0.0297, respectively). Significantly, most of these patients with no evidence of increased density pattern and scar-like pattern had PE (p=0.00038, 0.00044, respectively). CONCLUSION: Computed tomographic appearance after SBRT was classified into five patterns of acute radiation pneumonitis and three patterns of radiation fibrosis. Our results suggest that SBRT can be also safely performed even in patients with PE.

Aged↗

PubMed2006

The impact of motion artifacts on the reproducibility of repeated coronary artery calcium measurements.

The purpose of this study is, using a 16-section multidetector-row helical computed tomography (MDCT) scanner with retrospective reconstruction, to compare variability in repeated coronary calcium scoring and qualitative scores of the motion artifacts. One hundred forty-four patients underwent two subsequent scans using MDCT. According to Agatston and volume algorithms, the coronary calcium scores during mid-diastole (the center corresponding to 70% of the R-R cycle) were calculated and the inter-scan variability was obtained. Motion artifacts from coronary artery calcium were subjectively evaluated and classified using a 5-point scale: 1, excellent; no motion artifacts; 2, fine, minor motion artifacts; 3, moderate, mild motion artifacts; 4, bad, severe motion artifacts; 5, poor, doubling or discontinuity. Each reading was done by vessels (left main, left descending, left circumflex and right coronary arteries) and the motion artifact score (mean of the scales) was determined per patient. The variability in the low (1.2+/-0.2) and high (2.4+/-0.6) motion artifact score groups was 7+/-6 (median, 6)% and 19+/-15 (16)% on the Agatston score (P<0.01) and 7+/-7 (6)% and 16+/-13 (14)% on the volume score (P<0.01), respectively. In conclusion, motion has a significant impact on the reproducibility of coronary calcium scoring.

Adult↗

PubMed2006

[Development of computer-aided diagnostic system for detection of lung nodules in three-dimensional computed tomography images].

We have developed an automated computerized method for the detection of lung nodules in three-dimensional (3D) computed tomography (CT) images obtained by helical CT. In this scheme, a lung segmentation technique for the determination of the nodule search area is performed based on a gray-level thresholding technique. To enhance lung nodules, we employed the 3D cross-correlation method by using a 3D Gaussian template with zero-surrounding as a model of lung nodule. False positives are then eliminated by using a rule-base with 53 features. For further reduction of false positives, we performed linear discriminant analysis using these 53 features. The average number of false positives was 6.7 per case at a percent sensitivity of 85.0%. This computerized scheme will be useful to radiologists by providing a "second opinion" in case of possible early lung cancer.

Diagnosis, Computer-Assisted↗

PubMed2006

Pseudoaneurysm embolization and vasopressin infusion for lower gastrointestinal bleeding due to recurrence of urinary bladder carcinoma.

We report a case that was successfully treated for massive lower gastrointestinal (LGI) bleeding due to a recurrent urinary bladder carcinoma. Treatment consisted of combination therapy including embolization of an inferior gluteal artery (IGA) pseudoaneurysm and low-dose arterial vasopressin infusion via a sigmoid artery (SA). A 57-year-old man presented with life-threatening sudden, massive LGI bleeding due to an obturator lymph node (LN) metastasis from a urinary bladder carcinoma. Computed tomography showed that the LN recurrence had invaded all the way to the sigmoid colon, and there was a pseudoaneurysm with extravasation inside the recurrence. An angiogram revealed a left IGA pseudoaneurysm. We therefore excluded the pseudoaneurysm by embolization with microcoils. Following this treatment the bleeding decreased, but intermittent LGI bleeding continued. Endoscopic examination showed the tumor with a huge ulcer inside the colonic lumen, and continuous oozing was confirmed. A second angiogram showed no recurrence of the IGA pseudoaneurysm and no apparent findings of bleeding. Then a 3F microcatheter was placed in the SA selectively using a coaxial catheter system, and vasopressin was infused at a rate 0.05 U/min for 12 h. Bleeding completely ceased 2 days later. There were no signs of ischemic gastrointestinal complications. Massive LGI bleeding has not recurred in 5 months.

Aneurysm, False↗

PubMed2006

Timing on 16-slice scanner and implications for 64-slice cardiac CT: do you start scanning immediately after breath hold?

RATIONALE AND OBJECTIVES: Slow heart rate and small changes in heart rate are factors for improving image quality on spiral cardiac computed tomography (CT). The purpose of this study is to investigate whether it is possible to improve non-enhanced cardiac CT quality by delaying the data-acquisition window after breath hold. MATERIALS AND METHODS: Electrocardiograph files (n = 240) for 16-slice non-enhanced cardiac CT scans were analyzed. Mean heart rates and maximal changes in heart rates between adjacent cardiac cycles were compared between phase 1 (defined as cardiac cycles 1-5), phase 2 (cardiac cycles 2-6), ... , and phase 6 (cardiac cycles 6-10). RESULTS: Heart rates gradually increased by phases, but were limited to a range of 66.8-68.0 beats/min. Maximal changes in heart rates were 2.5 beats/min (phase 1) at the highest and 1.3 beats/min (phases 5 and 6) at the lowest (t-test; P < .01). Maximal changes in heart rates for more than five beats/min occurred in 24, eight, and eight patients on phases 1, 5, and 6, respectively (chi-square test; P < .01). CONCLUSION: The delayed scan (four or five cardiac cycles after breath hold) has the potential to improve the quality of non-enhanced cardiac CT.

Adult↗

PubMed2006

Multidetector CT angiography using a dual-head power injector and bolus tracking for the diagnosis of aortic aneurysms at reduced contrast material dosage.

RATIONALE AND OBJECTIVES: To establish the utility of multidetector computed tomography (CT) angiography using dual-head power injector in the diagnosis of aortic diseases. METHODS: In a prospective study, 151 patients with aortic diseases were examined by four-detector CT. Scanning was performed using bolus tracking technique. In all patients nonionic contrast was injected at the rate of 1.5 mL/sec. One hundred one patients were examined with dual-head power injector using 0.6 mL/kg contrast flushed by 30 mL of saline solution (group D). Fifty patients were examined with single-head power injector using 1.0 mL/kg contrast only (group S). We evaluated CT values at descending aorta, upper abdominal aorta, abdominal aortic bifurcation, and bilateral common femoral arteries. RESULTS: There were no statistically significant difference of CT values at descending aorta, upper abdominal aorta, abdominal aortic bifurcation, and right common femoral artery. At left common femoral artery, CT values in group D were higher than those in group S with statistically difference (P < .05). In group D, about 40% dose reduction was achieved without reducing image qualities. CONCLUSION: Multidetector CT angiography using dual-head power injector was valuable for the contrast dose reduction of aortic diseases.

Aged↗

PubMed2006

A feasibility study: evaluation of radiofrequency ablation therapy to hepatocellular carcinoma using image registration of preoperative and postoperative CT.

RATIONALE AND OBJECTIVES: The therapeutic response to radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC) often is evaluated by comparing pre- and post-RFA computed tomography (CT). However, judgment about whether an ablative margin, ie, 5-10 mm of normal hepatic tissue, is ensured sometimes is difficult. The aim of this study is to assess the feasibility of fusion images of pre- and post-RFA CT. MATERIALS AND METHODS: HCCs (n = 20) sized 13 +/- 5 mm (range, 4-23 mm) were included. For pre-RFA CT, the arterial phase of intravenous dynamic CT (n = 17), CT arterioportography (n = 2), and CT hepatic arteriography (n = 1) was used. Using automatic image registration software (n = 20) and a manual segmentation technique (n = 4), fusion images were created in combination with post-RFA CT (equilibrium phase of intravenous CT). RESULTS: Automatic image registration and manual segmentation technique took approximately 2-3 and 5 minutes, respectively. Total time required for the creation of fusion images was less than 10 minutes in all cases. Fusion images enabled easier understanding of the relationship between the tumor and ablation zone, helping judge whether an ablative margin was ensured. CONCLUSION: Fusion of pre- and post-RFA CT images is considered a feasible tool in the evaluation of RFA therapy for HCC.

Aged↗

PubMed2006

Variability of repeated coronary artery calcium measurements on low-dose ECG-gated 16-MDCT.

OBJECTIVE: High reproducibility on coronary artery calcium (CAC) scoring is a key requirement in monitoring the progression of coronary atherosclerosis. Retrospective ECG-gated helical CT has been shown to be superior to prospective gating helical CT in the reproducibility of CAC measurements. However, it brings with it a high level of radiation exposure. The purpose of this study was to compare low- and standard-dose protocols in the variability of CAC scores and in image quality, thereby assessing the feasibility of low-dose retrospective ECG-gated helical CT in CAC measurements. SUBJECTS AND METHODS: Eighty-six patients with CAC were scanned using a tube current setting of 100 mA once and then a tube current setting equivalent to the patient's body weight twice. CAC scores (Agatston and volume) and interscan variability were evaluated. The mean and SD of the CT attenuation values in regions of interest in the aorta were measured, and the value (mean + 2 x SD) was obtained. RESULTS: A high correlation of log(10) (Agatston score + 1) was observed between sequential helical CT scans (r = 0.998). The variability in CAC measurements ranged from 11% to 12% for both the Agatston and volume scores. With the tube current equivalent to body weight, the value (mean + 2 x SD) did not exceed a CT attenuation value of 130 H. CONCLUSION: Low-dose retrospective ECG-gated helical CT-yielding low variability and achieving the level of image quality needed to measure CAC-can be used to monitor patients with coronary atherosclerosis.

Adult↗

PubMed2006

Gynecologic abscess: CT-guided percutaneous drainage.

A 42-year-old woman with recurrent bilateral endometrial ovarian cystoma presented with fever and pelvic pain caused by a tubo-ovarian abscess (TOA), which was resistant to several varieties of intravenous and oral antibiotics for 2 weeks (Case 1). Computed tomography (CT)-guided diagnostic aspiration for a rapid enlarged right ovarian cystoma through a transabdominal route confirmed that it had developed into a TOA. Subsequent percutaneous abscess drainage (PAD) and irrigation for 3 days were successful. One-year follow-up revealed no recurrence of TOA. A 58-year-old woman with recurrent cervical cancer after external radiation therapy (RT) presented with fever, confusion and tremor caused by pyometra (Case 2). Since transvaginal drainage was impossible due to cervical os obstruction, the patient had undergone CT-guided transabdominal PAD and irrigation for a month. Thereafter, the clinical findings improved and a tracheloplasty was performed to prevent recurrence. CT-guided PAD may be a useful treatment option for gynecologic abscess as a diagnostic aspiration, a temporizing procedure until surgery, or an alternative surgery.

Abscess↗

PubMed2005

Electron beam CT versus 16-slice spiral CT: how accurately can we measure coronary artery calcium volume?

The purpose of this study was to investigate how accurately CAC volume we can be measured using electron beam computed tomography (CT) and 16-slice spiral CT. CAC models with known volume attached to a cardiac phantom were scanned. The error of measurement, variability between measured and real volumes, and inter-scan measurement variability were obtained. For spiral CT, seven different parameters were included: (1) slice thickness (0.625 mm, 1.25 mm and 2.5 mm), (2) retrospective spiral electrocardiograph (ECG)-gated or prospective axial ECG-triggering, (3) overlapping or non-overlapping. The error of measurement was 15% on electron beam CT and 8-20% on spiral CT. CAC volumes were underestimated in 92% and overestimated in 8% of the electron beam CT scans. Volumes were underestimated in 79%, correct in 5% and overestimated in 16% of the spiral CT scans. The best measurement and the least variability was observed on 0.625-mm retrospective spiral ECG-gated CT (error of 8%), a significant result (t-test: P<0.01) when compared with electron beam CT. CAC volume measurement on CT scanners may be significantly different and often underestimates the real volume of CAC. For precise evaluation of CAC volume, thin-slice retrospective spiral ECG-gated scan using a spiral CT scanner is desirable.

Artifacts↗

PubMed2005

Multiplanar reformat and volume rendering of a multidetector CT scan for path planning a fluoroscopic procedure on Gasserian ganglion block-a preliminary report.

In the treatment of trigeminal neuralgia, Gasserian block under fluoroscopical guidance may be difficult because of anatomic variability, and difficulty in identification of the foramen ovale. We introduce how to use three-dimensional CT in the preprocedural planning. We determine the skull-rotation angle in which the foramen ovale is best visualized, the relationship (distance, angle) between the virtual puncture point and anatomical landmarks, and the distance between the virtual puncture point and the foramen.

Aged↗

PubMed2005

Laparoscopic nephron-sparing surgery: preoperative assessment with three-dimensional computed tomography.

OBJECTIVE: For retroperitoneal laparoscopic nephron-sparing surgery using a microwave tissue coagulator, it is helpful to know the relationship between the tumour, collecting system and vessels to prevent urinary leakage and vascular damage. We assessed the efficacy of multiplanar reformation and three-dimensional (3D) CT with the renal collecting system filled with contrast medium. METHODS: Fifteen patients with small renal tumours of less than 3 cm in diameter underwent dynamic CT examination ten minutes after injection of contrast medium of 30 ml. Multiplanar reformation, volume-rendered and maximum intensity projection images were created for determining operative approaches and for planning the operation. RESULTS: In all cases, the distance between the tumour and collecting system was measured on the multiplanar reformation. Accordingly, five cases were indicated for retroperitoneal laparoscopic nephron-sparing surgery using a microwave tissue coagulator. The remaining ten cases, due to the short distance (less than 10mm), were not considered good candidates for this procedure. The relationship between the tumour, collecting system and vessels was well shown on the volume-rendered and maximum intensity projection images. CONCLUSIONS: Multiplanar reformation and 3D-CT are able to give us an understanding of the surrounding structures. They are helpful in defining the indications for retroperitoneal laparoscopic nephron-sparing surgery using a microwave tissue coagulator and preoperative planning of nephron-sparing surgery.

Aged↗

PubMed2005

Electron beam CT versus 16-MDCT on the variability of repeated coronary artery calcium measurements in a variable heart rate phantom.

OBJECTIVE: High reproducibility of coronary artery calcium (CAC) scoring is a key requirement for monitoring the progression of coronary atherosclerosis. The purposes of this study were to compare electron beam CT and 16-MDCT scanners in the variability of repeated CAC measurements and to assess the factors influencing this variability. MATERIALS AND METHODS: CAC models of different sizes attached to a cardiac phantom with a programmable variable heart rate were scanned three times, and interscan variability of the CAC measurement was calculated each time. For helical CT, different slice-thickness images of either retrospective ECG-gated or prospective ECG-triggering reconstruction were obtained. The detection of small amounts of calcium, variability of the Agatston score, and CAC measurement algorithms (Agatston, volume, and mass scores) were compared between CT scanners and protocols. RESULTS: All 1-mm-sized calcium models were detected on 0.625- and 1.25-mm helical CT, whereas some were missed on electron beam CT and 2.5-mm helical CT. Retrospective ECG-gated thin-slice helical CT showed the lowest variability. Reduction of variability by volume and mass scoring algorithms was less effective on 0.625- and 1.25-mm-thickness CT. CONCLUSION: Retrospective ECG-gated thin-slice helical CT has the potential to be a useful tool for monitoring coronary atherosclerosis.

Algorithms↗

PubMed2005

Variability of repeated coronary artery calcium measurements by 16-MDCT with retrospective reconstruction.

OBJECTIVE: High reproducibility on coronary calcium scoring is an important factor in monitoring the progression of coronary atherosclerosis. The purposes of this study were, using a 16-MDCT scanner with retrospective reconstruction, to compare the effects of thin-slice images and overlapping image reconstruction on the reproducibility of coronary calcium scoring and to compare 16-MDCT with electron beam CT (EBCT). MATERIALS AND METHODS: Fifty patients underwent two sequential examinations using both EBCT and MDCT. For MDCT, images were reconstructed from the same raw data using the following thicknesses and increments (thickness/increment): 1.25 mm/1.25 mm, 2.5 mm/2.5 mm, and 2.5 mm/1.25 mm. The Agatston, volume, and mass scores were calculated on four pairs of image sets. Statistical analysis was performed to determine significant differences in interscan variability among image acquisition protocols and among measurement algorithms. RESULTS: Overlapping reconstructed images (thickness/increment, 2.5 mm/1.25 mm) obtained on a 16-MDCT scanner showed the lowest variability (mean, 13%; median, 10%) when compared with the Agatston score. CONCLUSION: The use of 16-MDCT with overlapping reconstruction by retrospective reconstruction, yielding low variability of coronary artery calcium measurement on two sequential scans, has an advantage over EBCT in monitoring the progression of atherosclerosis.

Aged↗

PubMed2005

[Design and development of a new pulsating cardiac coronary phantom for ECG-gated CT and its experimental characteristics].

The optimal pulsating cardiac phantom is an important tool for the evaluation of cardiac images and cardiac applications on ECG-gated MDCT. The purpose of this study was to demonstrate the design and fabrication of the pulsating cardiac coronary phantom. The newly developed pulsating cardiac coronary phantom has the following five key advantages: 1) a driver component that uses only one servomotor to move the phantom in three dimensions (X, Y, and Z directions) with 16 presets of different heart types (heartbeat: 0-120 bpm; ejection fraction: 0-90%); 2) versatile pumping and filling phases to simulate a real heart in a cardiac cycle can be incorporated into the driver sequence including shift of patient heartbeat or irregular pulse (maximum: 200 different heart waves in one scan); 3) a cardiac coronary component constituted of an acrylic/silicon/rubber tube (2-6 mm inner diameter) with stent/in-stent restenosis/stenosis/soft plaque/calcification parts and maximum 16 coronary arteries that can be attached to the phantom in the same scan; 4) the complete phantom can be submerged in a tank to simulate the heart and its surrounding tissues; 5) ECG gating can be from interior trigger and exterior trigger. It has been confirmed that the developed pulsating cardiac phantom is very useful to quantitatively assess imaging of the heart and coronary arteries during phantom experiments.

Coronary Angiography↗

PubMed2004

Reproducibility of organ position using voluntary breath-hold method with spirometer for extracranial stereotactic radiotherapy.

PURPOSE: To evaluate in healthy volunteers the reproducibility of organ position using a voluntary breath-hold method with a spirometer and the feasibility of this method for extracranial stereotactic radiotherapy in a clinical setting. METHODS AND MATERIALS: For this study, 5 healthy volunteers were enrolled. After training sessions, they held their breath at the end-inspiration and the end-expiration phase under spirometer-based monitoring. Computed tomography (CT) scans were performed twice at each respiratory phase, with a 10-min interval, on 2 separate days. The total number of CT scans was four at each respiratory phase. After CT volume data were transferred to a three-dimensional treatment-planning system, digitally reconstructed radiographs (DRRs) were calculated for anterior-posterior and left-right beams. Verification was performed with DRRs relative to the diaphragm position, bony landmarks, and the isocenter in each healthy volunteer at each respiratory phase. To evaluate intrafraction reproducibility, we measured the distance between diaphragm position and bony landmarks. To evaluate interfraction reproducibility, we measured the distance between diaphragm position and the isocenter. Reproducibility and setup error were defined as the average value of the differences between each DRR with regard to the first DRR. RESULTS: Intrafraction reproducibility of the caudal-cranial direction was 4.0 +/- 3.5 mm at the end-inspiration phase and 2.2 +/- 2.0 mm at the end-expiration phase. Interfraction reproducibility of the caudal-cranial direction was 5.1 +/- 4.8 mm at the end-inspiration phase and 2.1 +/- 1.8 mm at the end-expiration phase. The end-expiration phase was more stable than the end-inspiration phase. CONCLUSIONS: The voluntary breath-hold method with a spirometer is feasible, with relatively good reproducibility. We are encouraged about the use of this technique clinically for extracranial stereotactic radiotherapy.

Diaphragm↗

PubMed2004

Coronary artery calcium scoring using 16-MDCT and a retrospective ECG-gating reconstruction algorithm.

OBJECTIVE: Our aim was to compare detection, quantification, and cardiovascular risk stratification of coronary artery calcium (CAC) between electron beam CT and 16-MDCT with retrospective reconstruction. SUBJECTS AND METHODS. One hundred patients underwent both electron beam CT and 16-MDCT, and coronary artery calcium score, volume, and mass were obtained. RESULTS: Correlation between the two CT scanners was high for both calcium score (r(2) = 0.955), volume (r(2) = 0.952), and mass (r(2) = 0.977). Although electron beam CT is viewed as the gold standard, the sensitivity and specificity in the detection of CAC using 16-MDCT with a threshold of 130 H were 98.7% and 100%, respectively. The variability of calcium scores between the two CT scanners (26.5%) was comparable with two electron beam CT scanners reported previously. The variability of calcium volume (20.7%) and mass (20.3%) was lower than that of the score (Student's t test, r = 0.05, 0.01). In clinical cardiovascular risk stratification based on two CT calcium scores, the Cohen's kappa value was 0.929. There was no significant difference between the two scanners using Wilcoxon's signed rank test (p = 0.157). CONCLUSION: The 16-MDCT scanner with retrospective reconstruction, showing high agreement for detection and quantification of CAC with electron beam CT, holds promise in the detection of coronary artery atherosclerosis.

Algorithms↗

PubMed2004

[Concurrent chemoradiation using daily low-dose CDDP and UFT-E for postoperative recurrent esophageal cancers].

We reported concurrent chemoradiation for postoperative recurrent esophageal cancer patients with lymph node metastases and a pulmonary metastasis. From October 2001 to January 2004, we treated 6 consecutive patients with radiation and concurrent chemotherapy using daily low-doses of CDDP and UFT-E. Of the 6 patients, 4 (67%) had a complete response and 2 (33%) a partial response, yielding an overall response rate of 100% (6/6). Five patients are now alive without cancers, and 1 patient died with cancer. Concurrent chemoradiation using daily low-doses of CDDP and UFT-E is feasible and seems to offer good results for recurrent esophageal cancer patients.

Administration, Oral↗