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Shuhei Komatsu

Publications and source records attributed to Shuhei Komatsu.

16 recordsLinked to original sources
PubMed2006

Four-dimensional measurement of lung tumor displacement using 256-multi-slice CT-scanner.

The concept of internal target volume is of marked importance for radiotherapy to lung tumors as respiration-induced motion is important. Individualized assessment of motion is required as tumor site may not predict the extent or pattern of tumor motion. We performed volumetric cine scanning using the 256-multi-slice CT (256MSCT) to study tumor motion during free breathing in 14 inpatients who were treated with carbon-ion radiotherapy. Motion assessment in 16 respiratory phases of the cine CT revealed most tumors to show hysteresis-like behavior. Isocenter displacement between peak exhalation and inhalation for the average of the right and left lungs were 7 mm, 7 mm and 15 mm for the upper, middle and lower lobes, respectively. Cine CT with the 256MSCT improved the evaluation of tumor displacement and overcomes some of the limitations associated with current CT methods. Volumetric cine CT data provides useful data on motion for planning in all radiation approaches for lung tumors.

Aged↗
PubMed2006

Respiratory correlated segment reconstruction algorithm towards four-dimensional radiation therapy using carbon ion beams.

PURPOSE: To enhance the precision of treatment planning for tumors which move under respiration, we developed a respiratory-correlated segment reconstruction method (RS) based on the Feldkamp--Davis--Kress algorithm (FDK) which provides high temporal resolution and a high signal-to-noise ratio. We compared full-scan (FS-FDK) and RS-FDK with regard to dose distribution in heavy ion treatment planning. MATERIALS AND METHODS: Data acquisition for RS-FDK is done using a respiratory sensing system in cine scan mode with a 256-multi-detector row CT (256-MDCT). To evaluate the accuracy of irradiation of moving tumors, dose distributions with each algorithm were compared in heavy ion treatment planning using beam parameters obtained with FS-FDK. RESULTS: Images obtained using RS-FDK did not show motion artifacts and visualized the edges of the liver and pulmonary vessels more clearly than those with FS-FDK. The iso-dose distributions for FS-FDK covered the target volume; in contrast, RS-FDK with the beam parameter of FS-FDK image provided an insufficient dose to the target and a considerable dose to normal tissues around it. CONCLUSIONS: The information provided by RS-FDK improves accuracy in the prescription of dose-to-target volume. Further, RS-FDK allows greater precision in the delivery of radiotherapy, including 4D radiation therapy.

Aged↗
PubMed2006

A combination-weighted Feldkamp-based reconstruction algorithm for cone-beam CT.

The combination-weighted Feldkamp algorithm (CW-FDK) was developed and tested in a phantom in order to reduce cone-beam artefacts and enhance cranio-caudal reconstruction coverage in an attempt to improve image quality when utilizing cone-beam computed tomography (CBCT). Using a 256-slice cone-beam CT (256CBCT), image quality (CT-number uniformity and geometrical accuracy) was quantitatively evaluated in phantom and clinical studies, and the results were compared to those obtained with the original Feldkamp algorithm. A clinical study was done in lung cancer patients under breath holding and free breathing. Image quality for the original Feldkamp algorithm is degraded at the edge of the scan region due to the missing volume, commensurate with the cranio-caudal distance between the reconstruction and central planes. The CW-FDK extended the reconstruction coverage to equal the scan coverage and improved reconstruction accuracy, unaffected by the cranio-caudal distance. The extended reconstruction coverage with good image quality provided by the CW-FDK will be clinically investigated for improving diagnostic and radiotherapy applications. In addition, this algorithm can also be adapted for use in relatively wide cone-angle CBCT such as with a flat-panel detector CBCT.

Algorithms↗
PubMed2006

Severity scoring systems for prognosis and efficacy of polymyxin B-immobilized fiber treatment for colonic perforation.

PURPOSE: There is no established system for predicting prognosis and evaluating the efficacy of antiseptic treatments such as polymyxin B-immobilized fiber (PMX) according to the severity of peritonitis in patients with colonic perforation. We investigated the predictive value of various severity scoring systems for survival and for the efficacy of antiseptic treatments, to identify high-risk patients. METHODS: We reviewed 26 consecutive patients who underwent emergency operations between 1996 and 2003 for colorectal perforation not caused by trauma or iatrogenic disease. Several severity scores, i.e., Acute Physiology and Chronic Health Evaluation II (APACHE II), Sequential Organ Failure Assessment (SOFA), Mannheim Peritonitis Index (MPI), and Multiple Organ Failure (MOF) were calculated and analyzed as predictive scoring systems for prognosis, survival and efficacy of PMX treatment. RESULTS: An APACHE II score of 19, a SOFA score of 8, an MPI score of 30, and an MOF score of 7 or more were significantly related to a poor prognosis. With or without PMX treatment, an APACHE II score of 15 or less, a SOFA score of 7 or less, an MPI score of 27 or less, and an MOF score of 7 or less were all related to a good prognosis. Conversely, all patients died when the severity scoring points were higher than 20 in APACHE II, higher than 12 in SOFA, and higher than 39 in MPI. When PMX treatment was given to patients with an intermediate score, no correlation between survival and its efficacy was found, except in the MOF scoring system. CONCLUSION: These severity scoring systems can assist with the prediction of prognosis. They may also be useful for determining if PMX treatment would be unnecessary or ineffective in certain patients. However, the optimal application of PMX treatment in selected patients according to the severity scoring systems needs further investigation.

Adult↗
PubMed2006

Intraoperative pathological investigation of recurrent nerve nodal metastasis can guide the decision whether to perform cervical lymph node dissection in thoracic esophageal cancer.

Three-field lymph node dissection has been widely used to treat thoracic esophageal cancer, but is very invasive and can cause serious complications. Whether cervical lymph node dissection should be performed in all patients with thoracic esophageal cancer remains controversial. We pathologically examined the recurrent nerve lymph nodes during surgery in patients with thoracic esophageal cancer to determine the presence or absence of lymph node involvement. In patients without recurrent nerve nodal involvement, cervical lymph node dissection was not performed. Treatment outcomes were analyzed to evaluate whether intraoperative pathological investigation was a useful procedure. Among 71 patients with thoracic esophageal cancer who underwent 3-field lymph node dissection, the rate of cervical lymph node metastasis was 40.9% in patients with recurrent nerve nodal metastasis on intraoperative pathological investigation, as compared with 10.2% in patients without recurrent nerve nodal metastasis (p=0.007). Multiple logistic-regression analysis showed that recurrent nerve nodal metastasis was a strong predictor of cervical lymph node metastasis (odds ratio, 2.98; 95% confidence interval, 1.139-7.775; p=0.03). Among 41 patients who underwent intraoperative pathological investigation, 10 had recurrent nerve nodal metastasis and underwent cervical lymph node dissection. Two of these patients had histological evidence of cervical lymph node metastasis. The remaining 31 patients had no recurrent nerve nodal metastasis on intraoperative pathological examination and therefore did not receive cervical lymph node dissection. None of these patients had cervical lymph node recurrence on follow-up. We compared patients who underwent intraoperative pathological investigation with those who underwent conventional 3-field lymph node dissection (without performing intraoperative pathological investigation). The rates of cervical lymph node recurrence were similar among the groups (2.6% vs. 6.7%), but the 3-year survival rate was significantly higher in the patients who underwent intraoperative pathological dissection (83.3%) than in those who underwent 3-field dissection (57.2%; p<0.05). Although this was a retrospective study, our results suggest that outcomes of patients undergoing cervical lymph node dissection according to the results of intraoperative pathological investigation are at least as good as those in patients undergoing 3-field lymph node dissection. We conclude that intraoperative pathological investigation of recurrent nerve nodal metastasis is useful for determining whether cervical lymph node dissection should be performed in patients with thoracic esophageal cancer.

Aged↗
PubMed2006

[A case of immunotherapy using OK-432 in combination with RFA for CRT-resistant recurrent tumors of esophageal cancer that presented itself in the intramediastinal omentum of gastric tube].

The greater omentum contains abundant lymphoid tissues composed of a lot of macrophages and lymphocytes, and plays an important role in a host defense system in the peritoneal cavity. Also, it is well known to be an initial site of peritoneal disseminated metastases. We experienced a rare case of a 60-year-old man with postoperative recurrence of esophageal cancer that presented itself in the greater omentum of the gastric tube reconstructed through a mediastinal route, as well as through mediastinal lymph-nodes. We performed CT-guided radiofrequency ablation (RFA) for recurrent omental tumor that was refractory to chemoradiation therapy and growing rapidly adjacent to the trachea. In combination with local control using RFA, we attempted a systemic immunotherapy using OK-432, by subcutaneous injection around RFA to accelerate host antitumor immune responses induced by antigen stimulation by RFA, based on the immunological property of the omentum. RFA induced a significant therapeutic effect on the omental tumor with massive necrotic change. However, no apparent size reduction was seen in the metastatic mediastinal lymph nodes, although an increase of peripheral blood lymphocytes was observed before and after RFA, and systemic host immune responses were stimulated by OK-432.

Antineoplastic Agents↗
PubMed2005

MR imaging of brain injury induced by carbon ion radiotherapy for head and neck tumors.

To clarify the characteristics of magnetic resonance (MR) imaging of radiation-induced brain injury following carbon ion radiotherapy and to observe the changes in lesions over time, we evaluated 40 patients with radiation-induced brain injury from carbon ion radiotherapy for head and neck tumors. Their primary lesions received a radiation dose of 48 to 70.4 Gray equivalent (GyE) in 16 to 18 fractions. MR imaging of radiation-induced brain injury was graded as follows: Grade 1: change in focal white matter; focal contrast enhancement and surrounding edema; Grade 2: nonenhanced area or cystic lesion in enhanced lesion; Grade 3: focal necrosis with mass effect; and Grade 4: mass effect requiring surgical intervention. Radiation-induced brain injury appeared as early as 2 months and as late as 57 months after carbon ion therapy (mean interval, 22.2 months). MR findings of initial lesion were Grade 1 in 26 cases (65.0%), Grade 2 in 13 (32.5%), and Grade 3 in 1 (2.5%). Brain injury was always found in the radiation field initially, but cystic lesion and edema later extended outside the field in 10 cases (25.0%). In follow-up MR studies, size of edema or enhanced lesion was reduced in 17 patients (42.5%) without treatment. Two cases with large cystic lesions required surgery. Improvement of radiation-induced brain injury was observed more often than had been previously described. Because edema and cystic lesion can occasionally extend outside the radiation field, such findings do not exclude the possibility of radiation-induced brain injury. Careful observation is recommended because cystic lesions can enlarge enough to require surgical treatment in some cases.

Adult↗
PubMed2005

Predictive value of the time-intensity curves on dynamic contrast-enhanced magnetic resonance imaging for lymphatic spreading in breast cancer.

PURPOSE: Dynamic contrast-enhanced magnetic resonance imaging (CE-MRI) has emerged as a promising diagnostic modality in various breast cancer treatments. However, little is known about the correlation between the pattern of time to signal intensity curves (TIC) on the CE-MRI and clinicopathologic features. This study was designed to investigate these correlations and evaluate the predictive value of TIC on CE-MRI in order to identify high-risk patients. METHODS: Between 2001 and 2003, 101 lesions were evaluated to detect malignancy on CE-MRI in 101 women who were suspected of having breast tumors based on either clinical findings or conventional imaging studies. Moreover, the clinicopathologic findings were compared with the pattern of TIC for the 69 surgically treated malignant lesions. RESULTS: In detecting malignancy, the sensitivity, specificity, and accuracy were 78.7%, 88.5%, and 81.2%, respectively, in the 101 breast lesions. Especially for the 69 surgically treated malignant lesions, in comparison with breast cancer tumors with the benign pattern of TIC, the breast cancer tumors with a malignant pattern were found more frequently in lymphatic invasion (P < 0.01) and lymph node metastasis (P < 0.005), although no statistical correlation regarding the histological type, tumor size, vascular invasion, extensive intraductal component, hormone receptor status, or pathological stage was noted between the two groups. According to a logistic regression model, lymph node metastasis was found to be a significant independent variable. CONCLUSION: The pattern of TIC could be used to predict lymphatic spreading associated with lymph node metastasis prior to surgery as well as to detect malignancy. Therefore, a more detailed evaluation should be made to identify the presence of lymphatic spreading in patients with a malignant pattern of TIC.

Adult↗
PubMed2005

A case of occult contralateral breast cancer incidentally detected by contrast-enhanced MRI; report of a case with review of literature.

We encountered a case of occult contralateral breast cancer, previously undetected by conventional imaging such as mammography (MMG) and ultrasonography (US), but incidentally detected by contrast-enhanced magnetic resonance imaging (CE-MRI). We present it here with a review of the literature. A 67-year-old Japanese woman was referred to our hospital in October 2000 because of a 1.5 cm right breast lump detected in a medical checkup. MMG, US and fine needle aspiration cytology revealed a cancerous lesion during the right breast. No mass lesion was palpable nor was any detected by MMG or US in the left breast. Bilateral breast CE-MRI was performed for more detailed evaluation. Consequently, an occult contralateral breast cancerous lesion was detected incidentally by CE-MRI, with the images showing rapid initial enhancement of time to signal intensity curves. Before surgery, bilateral breast lesions were diagnosed as invasive ductal carcinoma by open biopsy. She underwent bilateral breast conserving surgery with bilateral axillary lymph node dissection. The postoperative course was uneventful and no recurrence has been noted as of January 18th, 2004. CE-MRI of the contralateral breast should be of value as a routine screen in those patients with a known or suspected malignancy in one breast considering the limits of breast cancer detection by such conventional modalities as MMG and US.

Aged↗
PubMed2004

Comparison of intraductal spread on dynamic contrast-enhanced MRI with clinicopathologic features in breast cancer.

OBJECTIVE: Contrast-enhanced magnetic resonance imaging (CE-MRI) has emerged as a new diagnostic technology in various breast cancer treatments. However, little is known about the correlation between intraductal spread on CE-MRI and clinicopathologic features. This study was designed to evaluate these correlations for the surgical planning of breast cancer. METHODS: Twenty-six breast cancer lesions (in 26 female patients) treated by breast conserving surgery between March 2001 and March 2003 were evaluated retrospectively. CE-MRI was performed with a 1.5 T unit using a dedicated bilateral breast coil. RESULTS: In detecting intraductal spread of breast cancer, the sensitivity, specificity and accuracy of CE-MRI were 82.4%, 60.0% and 77.3%, respectively. On mammography (MMG), these were 21.1%, 100.0% and 42.3%, respectively. Therefore, CE-MRI has a higher sensitivity and accuracy, although with a lower specificity than MMG. Compared with breast cancer lesions without intraductal spread on CE-MRI, lesions with intraductal spread on CE-MRI were found more frequently in larger-sized tumors (P = 0.0088). CONCLUSION: Preoperative evaluation for intraductal spread by CE-MRI should be more useful than by MMG for breast cancer. When making the surgical decision regarding excision range, particular attention should be paid to this consideration for patients with larger-sized cancer tumors.

Aged↗
PubMed2004

Carvedilol therapy improved left ventricular function in a patient with arrhythmogenic right ventricular cardiomyopathy.

An asymptomatic 35 year-old man was referred to our hospital because of abnormal ECG findings. The ECG showed complete right bundle branch block and left anterior hemiblock. Echocardiography revealed a moderately enlarged right ventricle (RV) and an apical aneurysm. RV wall motion showed diffusely moderate impairment, while the systolic function of the left ventricle (LV) was slightly decreased. The ejection fractions (EF) of the RV and LV were calculated as 28.1% and 41.9% by Simpson's method using multiple cardiac computed tomography (CT) scans. A 24 hour ambulatory ECG showed only 372 single premature ventricular contractions (PVC). Cardiac catheterizaion revealed that the RV was enlarged with prominent trabeculation and decreased motion. In an electrophysiologic study, neither electrical stimulation of the RV nor electrical stimulation plus isoproterenol infusion could induce ventricular tachycardia. Pathological examination of a biopsy from the interventricular septum of the RV revealed fibrofatty change in the myocardium. Based on these results, we made a diagnosis of arrhythmogenic right ventriclular cardiomyopathy (ARVC) and administered 5 mg of carvedilol. Sixty days after the initiation of carvedilol therapy, we performed repeat cardiac CT. The EF of the LV was markedly improved from 41.9% to 62.0%, although the EF of the RV was not changed. The number of PVCs showed no change. This case suggests that carvedilol is not only useful for controlling arrhythmia but also for improving left ventriclular function in some patients with ARVC. Sympathetic overactivity is reported to cause sudden death, so carvedilol may be a first-line drug for some patients with ARVC.

Adrenergic beta-Antagonists↗
PubMed2002

Vector analysis of the wall shear rate at the human aortoiliac bifurcation using cine MR velocity mapping.

OBJECTIVE: Small or oscillatory wall shear stress accelerates atherosclerosis. MR velocity mapping is feasible for vector analysis of wall shear rate (a spatial gradient of blood flow velocity at the vessel wall) in humans. A relationship between anatomic variations at the aortoiliac bifurcation and characteristics of wall shear rate was evaluated. SUBJECTS AND METHODS: To obtain two components of wall shear rate vectors, an axial component along the vessel axis and a nonaxial component perpendicular to the former at the inner and outer walls of the common iliac arteries just distal to the aortoiliac bifurcation, we performed cine MR velocity mapping with three orthogonal velocity-encoded directions in seven volunteers. RESULTS: The peak axial component at the outer wall (120.6 +/- 37.2 sec(-1)) was smaller than that at the inner wall (196.0 +/- 53.7 sec(-1)) (p < 0.01). Oscillation described by a time integral of the axial component in recessive blood flow direction over integrals in dominant and recessive directions at the outer wall was greater (0.24 +/- 0.11) than that at the inner wall (0.15 +/- 0.08) (p < 0.01). The intersecting angle between the extrapolation of the aortic axis and the direction of the axis of the common iliac artery correlated positively with the peak axial component (r = 0.577, p < 0.05) and inversely with oscillation (r = 0.603, p < 0.05). CONCLUSION: Three-dimensional vector analysis with MR velocity mapping revealed that the outer wall at the aortoiliac bifurcation showed low and oscillatory shear rate, and this inclination was increased when the takeoff angle of the iliac artery was small.

Adult↗
PubMedDate not supplied

Prognostic factors and scoring system for survival in colonic perforation.

BACKGROUND/AIMS: No ideal and generally accepted prognostic factors and scoring systems exist to determine the prognosis of peritonitis associated with colonic perforation. This study was designed to investigate prognostic factors and evaluate the various scoring systems to allow identification of high-risk patients. METHODOLOGY: Between 1996 and 2003, excluding iatrogenic and trauma cases, 26 consecutive patients underwent emergency operations for colorectal perforation and were selected for this retrospective study. Several clinical factors were analyzed as possible predictive factors, and APACHE II, SOFA, MPI, and MOF scores were calculated. RESULTS: The overall mortality was 26.9%. Compared with the survivors, non-survivors were found more frequently in Hinchey's stage III-IV, a low preoperative marker of pH, base excess (BE), and a low postoperative marker of white blood cell count, PaO2/FiO2 ratio, and renal output (24h). According to the logistic regression model, BE was a significant independent variable. Concerning the prognostic scoring systems, an APACHE II score of 19, a SOFA score of 8, an MPI score of 30, and an MOF score of 7 or more were significantly related to poor prognosis. CONCLUSIONS: Preoperative BE and postoperative white blood cell count were reliable prognostic factors and early classification using prognostic scoring systems at specific points in the disease process are useful to improve our understanding of the problems involved.

APACHE↗
PubMedDate not supplied

Survival and clinical evaluation of salvage operation for cervical lymph node recurrence in esophageal cancer.

BACKGROUND/AIMS: Although extended lymphadenectomy for thoracic esophageal cancer is widely practiced in Japan, solitary supraclavicular lymph node recurrence (SCLR) has often become a problem. This study was designed to evaluate the survival and clinical benefit of salvage cervical lymphadenectomy. METHODOLOGY: Between 1989 and 2001, 153 patients underwent esophagectomy for esophageal cancers. SCLR was identified in 5 (3.7%) patients and these five patients were examined retrospectively. RESULTS: Surgical treatment was performed intensively for all patients. Two patients showed longterm survival for 7 years 3 months and 4 years, respectively. Four patients belonged to the good prognostic group but the other patient had poor prognosis from the viewpoint of both the pathological metastatic lymph node number and disease-free interval (DFI). There were no local recurrences but were a recurrent laryngeal nerve palsy in three patients associated with treatment. CONCLUSIONS: Salvage cervical lymphadenectomy for SCLR should be performed positively by selecting each case carefully. Indication must be weighed against increased morbidity considering such indicators as the extent of metastatic lymph node numbers and DFI.

Aged↗
PubMedDate not supplied

Prognostic and clinical evaluation of patients with T2 gastric cancer.

BACKGROUND/AIMS: Little is known about the clinicopathological features of intermediate-stage T2 gastric cancer, defined as tumors invading the muscularis propria or subserosa. METHODOLOGY: Of 808 patients with gastric cancer, 210 patients (25.9%) who underwent gastrectomy for T2 gastric cancer were selected for this retrospective study. The clinicopathologic findings of these patients were analyzed retrospectively from their hospital records. RESULTS: Of all 808 patients with gastric cancer, 73 patients (9.0%) had tumors invading the muscularis propria (mp). The remaining 137 patients (16.9%) had tumors invading the subserosa (ss). Compared with ss gastric cancer, mp gastric cancer was associated with smaller tumor size, an absence of lymphatic spreading, and hematogenous and late recurrence [disease-free interval: 654.5 days (mp) vs. 365.5 days (ss)]. Univariate analysis of cases with curative operations showed that lymphatic invasion, and lymph node metastasis were significant prognostic factors in patients with T2 gastric cancer. Further examination by multivariate analysis demonstrated that pN2 or higher as classified by both the JCGC (Japanese Classification of Gastric Cancer) and the TNM lymph node staging systems was a predictor of poor prognosis. CONCLUSIONS: JCGC and TNM lymph node staging systems were the most reliable prognostic factors for T2 gastric cancer. Close follow-up should be required for patients with stage pN2 or higher gastric cancer. Long-term follow-up should be required for mp cancers, in particular.

Adult↗