Anatomy and physiology of hamstring injury.

The hamstring muscles were analyzed anatomically and physiologically to clarify the specific reasons for the incidence of muscle strain of the hamstrings. For the anatomical study, hamstring muscles of 13 embalmed cadavers were dissected. For the physiological study, the knee flexor torque and surface electromyographic (EMG) signals were measured during isometric contraction of hamstring muscles in 10 healthy adults. The biceps femoris muscle long head (BF-L) and semimembranosus muscle (SM) had hemi-pennate architecture and their fiber length per total muscle length (FL/TML) was smaller than that of semtendinosus muscle (ST) and biceps femoris muscle short head (BF-S) with other architecture. The decrease of total muscle length per fiber length (ΔTML/FL) was larger in BF-L and SM than in ST and BF-S. The EMG activities at 0° of knee angle were at maximal compared with other knee angles and were of similar level in BF-L, in SM and in ST, whereas they were considerably smaller in BF-S. The EMG at 0° of knee angle activity per physiological cross-sectional area (PCSA) was about 1.6 times greater in BF-L than in SM. These results indicate the highest risk of muscle strain was in BF-L followed by SM.

Percutaneous transhepatic portal vein embolization: effectiveness of absolute ethanol infusion with balloon catheter in a pig model.

PURPOSE: To evaluate the effectiveness of portal vein embolization (PVE) with absolute ethanol using multidetector-row computed tomography (CT) angiography in a pig model. MATERIAL AND METHODS: Percutaneous transhepatic PVE with 10 ml absolute ethanol was performed in liver segments (n = 5) or subsegments (n = 5) in 10 pigs. CT images and volumetric data were qualitatively and quantitatively assessed to determine future liver remnant (FLR) hypertrophy and to correlate with histopathologic changes 2-6 weeks after PVE. Effectiveness evaluation was based on changes in absolute FLR size and ratio of FLR to total estimated liver volume (TELV). RESULTS: Occlusion of the embolized vessel was achieved immediately after injecting absolute ethanol within a range of 0.25-0.33 ml/kg. The TELV prior to PVE was 660.49 +/- 103.66 cm3 (range 527.22 to 833.70 cm3) and after PVE 769.51 +/- 29.36 cm3 (range 685.95 to 887.34 cm3). The mean FLR/TELV ratio increase after PVE was 14.2%. No statistically significant difference was found in the increase of TELV between segmental or subsegmental PVE. On microscopic observation, atrophy of the embolized liver was noted in all animals and was seen distinctly at 3 weeks after PVE in 2 animals. CONCLUSION: Both regenerative response and histopathologic changes of the liver were seen after PVE with absolute ethanol with a mean FLR/TELV ratio of 14.2%.

Detection and characterization of focal liver lesions using superparamagnetic iron oxide-enhanced magnetic resonance imaging: comparison between ferumoxides-enhanced T1-weighted imaging and delayed-phase gadolinium-enhanced T1-weighted imaging.

BACKGROUND: Double contrast magnetic resonance (MR) imaging using superparamagnetic iron oxide (SPIO) and gadolinium (Gd) is performed to detect and characterize focal liver lesions. However, this technique is a costly and lengthy process. The purpose of this study was to determine the usefulness of SPIO-enhanced MR imaging including SPIO-enhanced T1-weighted imaging in diagnosing focal liver lesions. METHODS: Eighty-four focal liver lesions were examined with a 1.5-T MR unit. Transverse precontrast T1- and T2-weighted images and SPIO (ferumoxides)-enhanced T1- and T2-weighted images were obtained, followed by Gd-enhanced T1 -weighted imaging. The Gd set (i.e., precontrast T1- and T2-weighted and delayed-phase gadolinium-enhanced T1-weighted images) and ferumoxides set (i.e., precontrast T1- and ferumoxides-enhanced T1- and T2-weighted images) were reviewed by two independent readers. RESULTS: More lesions were detected from the ferumoxides set than from the Gd set. Ferumoxides-enhanced T1-weighted imaging showed enhancement patterns of the lesions similar to those of delayed-phase Gd-enhanced T1-weighted imaging. The diagnoses of hepatic metastasis and cyst by the ferumoxides set were similar to those by the Gd set. However, a dynamic study may be inevitable for the diagnosis of hepatocellular carcinoma and hemangioma. CONCLUSION: The ferumoxides set was useful for the detection of focal hepatic lesions. Ferumoxides-enhanced T1-weighted imaging may replace delayed-phase gadolinium-enhanced T1-weighted imaging in the diagnosis of hepatic metastasis and cysts.

Hand-assisted laparoscopic hepatectomy after partial splenic embolization.

The case of a patient with hepatocellular carcinoma and thrombocytopenia secondary to liver cirrhosis who underwent successful hand-assisted laparoscopic hepatectomy after partial splenic embolization is described. A 67-year-old man with severe liver cirrhosis was admitted for treatment of hepatocellular carcinoma. His early phase of hepatic angiography showed two hypervascular tumors in segment 6. The patients liver function was poor, with the indocyanine green retention at 15 min of 49.5%, a total serum bilirubin concentration of 2.0 mg/dl, an albumin concentration of 2.8 g/dl, and an hyaluronic acid concentration of 649 ng/ml. The platelet count was 3.0 x 10(4)/microl secondary to hypersplenism. Partial splenic embolization decreased the splenic volume by 50% preoperatively. At 2 months later, the platelet count was 6.0 x 10(4)/microl, and hand-assisted laparoscopic partial hepatectomy was performed uneventfully. The patients postoperative course was unremarkable, and he was discharged on postoperative day 12.

Plasma endothelin, nitric oxide and atrial natriuretic peptide levels in humans after abdominal angiography.

PURPOSE: To clarify the effect of the contrast medium iopamidol on endothelial function and response of vasoactive peptide, as measured by changes in the levels of plasma endothelin, nitric oxide and atrial natriuretic peptide. MATERIAL AND METHODS: Thirteen patients received iopamidol 300 mg I/ml intra-arterially during routine abdominal angiography. The mean volume of contrast medium administered was 208.1+/-32.5 ml. Endothelin, nitric oxide and atrial natriuretic peptide were measured before and after angiography. RESULTS: Endothelin levels increased significantly (from 1.45+/-0.12 pg/ml to 1.90+/-0.10 pg/ml) after exposure to contrast medium. Nitric oxide levels decreased significantly (from 34.56+/-2.23 micromol/ to 25.43+/-1.83 micromol/l). Atrial natriuretic peptide levels increased significantly (from 11.43+/-1.68 pg/ml to 21.28+/-2.89 pg/ml). CONCLUSION: Exposure to contrast medium in humans is associated with an increase in plasma endothelin levels and a decrease in nitric oxide levels, and atrial natriuretic peptide levels also increase following CM injection.

Assessment of abdominal aortic aneurysms using a cone-beam CT system: an experimental phantom study and an initial clinical evaluation before and after stent-graft treatment in patients with an abdominal aortic aneurysm.

The aim of this study is to conduct a quantitative analysis of cone-beam CT (CBCT) images using a phantom, and then to evaluate the clinical usefulness of CBCT in the assessment of abdominal aortic aneurysms (AAA) before and after stent-grafting, both qualitatively as well as quantitatively. The phantom used in this study was a rectangular plate made of an acrylic resin, which contained eight through-holes to mimic blood vessels. Each columnar cavity was filled with contrast media and the diameter of each was then measured using a cone-beam multiplanar reformation/curved planar reformation (CB-MPR/CPR) technique, and the results were compared with the corresponding results obtained by actual measurement. In the clinical assessment, nine patients with AAA (consisting only of males with an average age of 68 years old: 56 approximately 80) were enrolled. The clinical qualitative analysis of CBCT consisted of: 1) for the pre-operative state, the shape of the aortic aneurysm, the relationship between the aneurysm and the aortic branches, and 2) for the post-operative state, the shape of the stent and any endoleakage present. The clinical quantitative analysis of CBCT included, for the aneurysm, its inflection angle, its maximum diameter, the diameter of the proximal and distal necks, and the distance of these two necks from specific reference points. The quantitative analysis using the phantom showed no significant differences between the results based on CB-MPR/CPR and those obtained by actual measurement. In the clinical qualitative analysis three-dimensional CBCT (3D-CBCT) depicted the anatomical relationship between the aneurysm and the aortic branches well, an accomplishment that was not possible by conventional angiography. Cone-beam maximum intensity projection (CB-MIP) was as good in tracing the migration and deformation of the stent following endovascular intervention as plain radiograms and conventional angiograms. CB-MPR/CPR enabled us to obtain any cross-sectional image of the aorta desired, including a curved, longitudinal cross-section of the aorta. Thus, with the CB-MPR/CPR technique it is easy to determine the distance of the proximal and distal necks of the aneurysm, and the inflection angle, and those results were not significantly different from those obtained by angiography. The diameter of the aneurysm, and the diameter of the proximal and distal necks as measured by CB-MPR/CPR images were significantly different from those obtained by conventional contrast enhanced-CT (p<0.05). This suggests that CB-MPR/CPR yields a cross-sectional view that is more perpendicular to the longitudinal direction of the aorta than that given by conventional contrast enhanced-CT, and thus provides a more accurate cross-sectional image of the aneurysm than the latter. We conclude that, in the experimental phantom study CBCT had a high quantitative reliability, and that, in the clinical study CBCT provided useful information for both qualitatively and quantitatively evaluating AAA before and after stent-grafting.

Primary pericardial mesothelioma: a case report.

The imaging features of primary pericardial mesothelioma have rarely been described. Herein we present a case report of its diagnostic-pathologic features. Chest computed tomography (CT) revealed an irregularly enhanced mass occupying the entire pericardial space and surrounding the superior vena cava. At autopsy, the tumor was found to fill the pericardial space completely, and to extend to the superior vena cava through the superior pericardial sinus. The CT features of the tumor were correlated well with those revealed at autopsy, and provided satisfactory information regarding the presence and the extension of the tumor.

Is technetium-99m-MIBI taken up by the normal pituitary gland? A comparison of normal pituitary glands and pituitary adenomas.

PURPOSE: The aim of this study was to compare the behavioral uptake of a normal gland and a pituitary adenoma and to assess the ability to diagnose pituitary adenoma by means of technetium-99m-hexakis-2-methoxy-isobutyl-isonitrile (MIBI) single photon emission computed tomography (SPECT). METHODS: The study included 15 patients with pituitary adenomas (mean age = 44.0 years, range 19-63) and 15 control subjects (mean age = 50.7 years, range 20-67). SPECT was performed 15 minutes after an intravenous injection of MIBI 600 MBq. The shape and location of MIBI uptake were evaluated on a magnetic resonance (MR) imaging/SPECT registration image. The shape patterns and location were classified as follows: Shape C (circular); LO (longitudinal oval); T/R (triangular or rectangular) and location P (pituitary gland or adenoma); D/C (dorsum sellae and/or clivus). RESULTS: Analysis of the uptake showed that 10 (67%) adenomas were C, and 5 (33%) were LO. Of the controls, 5 (33%) were C, and 10 (69%) were T/R. With regard to location, all patients with pituitary adenomas were classified as P, and all control subjects (93%) but one showed uptake in the dorsum sellae and clivus (D/C). CONCLUSION: MIBI was taken up in the dorsum sellae or clivus but not the normal pituitary gland and had a strong affinity for the pituitary adenoma. This result implies that MIBI SPECT may be a useful new auxiliary examination technique for the location diagnosis of pituitary adenoma.

Unique action determinants of double acting topoisomerase inhibitor, TAS-103.

O6-methylguanine-DNA methyltransferase (MGMT), gamma-glutamylcysteine synthetase (gamma-GCS), and glutathione (GSH) are found to participate in resistance to TAS-103, a topoisomerase I/II inhibitor. In 13 human cancer cell lines, MGMT expression correlated with IC50 for TAS-103, whereas gamma-GCS expression inversely correlated with the IC50 value, suggesting MGMT may work to decrease TAS-103 activity but gamma-GCS may increase it. A reduced gamma-GCS and GSH, and an increased MGMT were associated with the development of resistance in A549 and DLD cells, and gamma-GCS inhibition by buthionine sulphoximine increased the TAS-103 resistance, whereas MGMT inhibition by both O6-benzyl-guanine and MGMT-antisense transfection sensitized cells to TAS-103.

Assessment of left ventricular diastolic function with electrocardiography-gated myocardial perfusion SPECT: comparison with multigated equilibrium radionuclide angiography.

BACKGROUND: Technetium-labeled myocardial perfusion tracers allow the simultaneous assessment of myocardial perfusion and left ventricular function by electrocardiography (ECG)-gated myocardial perfusion single photon emission computed tomography (SPECT). This study evaluates left ventricular systolic and diastolic function by ECG-gated SPECT with the use of higher framing (32 frames per cardiac cycle) data acquisition. METHODS AND RESULTS: After receiving an injection of technetium 99m tetrofosmin, 48 patients with cardiac diseases were examined by ECG-gated myocardial perfusion SPECT with a 3-headed gamma camera. During gated data collection, 32 frames per cardiac cycle were acquired over 360 degrees in 60 steps, each of which consisted of 60 beats. Immediately thereafter, the 32 frames taken at each projection angle were combined into 16-frame and 8-frame data sets. Left ventricular end-diastolic volume (LVEDV, in milliliters), left ventricular end-systolic volume (LVESV, in milliliters), and left ventricular ejection fraction (LVEF, percentage) were automatically calculated from the 32-frame, 16-frame, and 8-frame gated data sets. Left ventricular time-volume curves from the 3 data sets were generated by Fourier curve fitting analysis with the use of 3 harmonics, and then peak filling rate (PFR, per second) was measured. Twenty-nine patients also underwent multigated equilibrium radionuclide angiography (ERNA) to determine the LVEF and PFR. Combining the 32-frame data into 16-frame and 8-frame data sets from the 48 patients generated a smaller LVEDV and a larger LVESV, and LVEF was significantly lower in accordance with the decreasing number of frames. Compared with ERNA studies (n = 29), the Bland-Altman method showed underestimated LVEFs and larger 95% limits of agreement in lower framing gated SPECT. CONCLUSIONS: Left ventricular functional parameters obtained from 32-frame gated SPECT correlated closely with those determined by ERNA studies. ECG-gated SPECT with 32-frame data can provide comprehensive information with which to evaluate many types of cardiac diseases.

Celiac artery aneurysm: a case evaluated preoperatively with three-dimensional computed tomographic angiography.

In a 63-year-old woman computed tomography (CT) incidentally detected a celiac artery aneurysm approximately 3 cm in diameter. While conventional angiography suggested that the splenic artery and common hepatic artery arose from the celiac artery aneurysm, three-dimensional CT angiography indicated that the aneurysm involved only the mid portion of the celiac artery. Considering the risk of eventual aneurysm rupture, surgery was performed. Aneurysmectomy and devascularization of hepatic, splenic, and celiac arteries were carried out following complete cross-clamping of the celiac artery. The distal segment of the celiac artery was directly anastomosed to the proximal segment in an end-to-end fashion. Histologically, the aneurysm wall showed atheromatous changes. Contrast-enhanced abdominal CT confirmed complete removal of the celiac artery aneurysm, and postoperative angiography confirmed good arterial flow. The patient recovered uneventfully after surgery, with normalization of transiently abnormal hepatic function parameters. In this case of celiac artery aneurysm, three-dimensional CT angiography was found to be valuable in determining the relationships of the aneurysms to important arterial branches.

Senescent cells are resistant to death despite low Bcl-2 level.

Cellular senescence may be an antioncogenic event. Bcl-2 is a product of the oncogene, bcl-2, but it may also participate in cellular senescence. To investigate the role of Bcl-2, we analyzed the level of Bcl-2 during aging of normal human fibroblasts by immunoblot analysis and found that its level was highly suppressed in four normal senescent fibroblast strains. This result suggests that senescent cells are more sensitive to induction of death than young cells. Nevertheless, senescent cells showed more resistance to death induced by hydrogen peroxide than young cells, according to LDH assay. Because the balance among antiapoptotic and proapoptotic proteins is an important factor for the determination of cell death, we examined levels of other Bcl-2 family and apoptosis-regulating proteins, but observed no reasonable change to explain the resistance. During the course of the death induction experiment, we obtained results showing that growth-arrested cells were also resistant to death, and this was further confirmed by a BrdU-labeling experiment. As senescent cells are stopped permanently in the G0/G1-phase of the cell cycle, our data strongly suggest that this is the cause of resistance to death in senescent cells.

Study on the treatment of tracheobronchial stenosis using expandable metallic stents.

The purpose of this study is to clarify the clinical usefulness of Gianturco-Z stent (G-Z stent) for the management of malignant and benign tracheobronchial stenosis. Seventy-three stents were used in 30 patients. In 20 cases, we used the so-called "stent-in-stent" method. Twenty-four patients were grade 5, and 6 were grade 4 according to the Hugh-Jones classification of respiratory status. The technical success rates, clinical condition, respiratory status, blood gas analysis, survival rate, and complications were reviewed on the basis of the patients'medical records and radiographs. All stents were successfully placed in the appropriate position. After the procedure, respiratory status improved in 97% (29/30) of the patients. PaO(2) increased statistically (p<0.05), and PaCO(2) decreased one week after the treatment. Mean survival of 30 patients after stent placement was 123 days. Mean survival in 9 malignant patients treated in combination with radiotherapy (182 days) was statistically longer (p<0.01) than in those treated without radiotherapy (65 days, n=20). The tracheobronchial burn patient who received a combination of stent placement and post operative radiotherapy survived 540 days. No major complications were encountered during or after the procedure. Only 3 minor complications were observed: 1 stent migration, 1 partial rupture of the stent, and 1 stent deformation. G-Z stent treatment with the "stent-in-stent" technique is useful for palliation of malignant and benign tracheobronchial stenosis, and should contribute to improving the quality of life in patients with advanced cancer.

[Assessment of left ventricular function with the solid-state digirad 2020tc Imager].

Multigated equilibrium radionuclide ventriculography from best septal position (LAO view) was performed in 17 patients with cardiac disease with a single detector Anger-type gamma camera (GCA 602A, Toshiba), then immediately imaged with a solid-state, multi-crystal gamma camera (Digirad 2020tc Imager). Acquisition times were the same of 10 minutes. The solid-state gamma camera uses CsI(Tl) as the scintillation material and a Si photodiode. CsI(Tl) has a higher density and higher atomic number than NaI(Tl), so that its efficiency for detecting gamma rays is higher. To confirm this, total acquisition counts in 17 patients obtained from the 2020tc Imager were significantly higher than those obtained from the Anger-type camera (7847 +/- 2061 K vs. 4427 +/- 1162 K counts, p < 0.0001). In comparing left ventricular ejection fractions obtained from the Anger-type camera and the 2020tc Imager data, an excellent correlation was revealed with a correlation coefficient of 0.97 (p < 0.0001). Again, peak ejection rate and peak filling rate obtained from the 2020tc Imager data correlated well with those obtained from the Anger-type camera data (r = 0.93, p < 0.0001 and r = 0.80, p < 0.001, respectively). These data reveal that the 2020tc Imager has an excellent data collection efficiency and a high reliability in assessment of left ventricular function. Thus, the solid-state gamma camera was thought to be a useful hardware in nuclear cardiology.

Peak blood flow measurement of coronary sinus by cine phase contrast MR imagings: comparison between breath-hold and respiratory compensation techniques.

The aim of this study was to assess the feasibility of cine phase contrast (PC) magnetic resonance (MR) imaging for the peak blood flow measurement of the coronary sinus. Conventional PC imaging demonstrated the coronary sinus clearly and the significantly higher peak flow compared with the corresponding values measured with breath-hold fast cine PC imaging techniques at end-inspiration and end-expiration. This study showed the feasibility of conventional cine PC imaging with respiratory compensation in measurement of coronary sinus blood flow.

MRI findings of a case of uterine tumor resembling ovarian sex-cord tumors coexisting with endometrial adenoacanthoma.

A case of uterine tumor resembling ovarian sex-cord tumors is reported. MRI was performed for the staging of the endometrial adenoacanthoma diagnosed by biopsy. A well-defined, slightly hyperintense mass with central hypointensity was noted in the myometrium on T2-weighted images. Pathological diagnosis of the myometrial mass was uterine tumor resembling ovarian sex-cord tumors. The central hypointense area was a leiomyomatous component. Adenoacanthoma was also confirmed. These features of coexisting tumors correlated well with the MRI findings.

Direct MR arthrography of plica synovialis mediopatellaris.

OBJECTIVE: To evaluate the efficacy of direct MR arthrography for diagnosing plica synovialis mediopatellaris (PSM). MATERIAL AND METHODS: Twenty-two knees of 19 patients were examined by direct MR arthrography. In 19 of those knees, field-echo T2*-weighted transaxial images were obtained with intra-articular administration of 40 ml of saline ("direct MR arthrography"). In the other 3 knees, T1-weighted transaxial images were obtained with intra-articular administration of 40 ml of gadopentetate dimeglumine. Conventional MR images were evaluated prior to direct MR arthrography in 12 of the 22 knees. The results of direct MR arthrography and conventional MR imaging were compared with the arthroscopic findings. RESULTS: Direct MR arthrography demonstrated 17 of 19 PSMs proved on arthroscopy. The features of 16 PSMs on direct MR arthrography corresponded accurately with the arthroscopic classification. Conventional MR demonstrated only 3 plicae. CONCLUSION: Direct MR arthrography enabled accurate diagnosis of PSMs and could replace diagnostic arthroscopy.

Safety of gadolinium contrast agent in hemodialysis patients.

PURPOSE: We evaluated the safety of a gadolinium (Gd) contrast agent in hemodialysis patients. MATERIAL AND METHODS: Seventy hemodialysis patients underwent contrast-enhanced MR examination. After the examination, the patients were hemodialyzed on a usual schedule, i.e., 3 times per week at 4 h each session. The hemodialysis was performed on the same day in 16 patients, the next day in 34, 2 days later in 14 and 3 days later in 6 patients. Serum Gd concentrations before and after the first to fourth hemodialysis sessions were analyzed in 11 patients. Cardiovascular, cutaneous, respiratory, psycho-neurological and digestive side effects were evaluated in all patients. Changes in liver and kidney functions, blood counts, and electrolytes were also checked. RESULTS AND CONCLUSION: Neither side effects nor blood changes were noted in any of the patients. Average excretory rates were 78.2%, 95.6%, 98.7% and 99.5% in the first to fourth hemodialysis sessions, respectively. These results suggest that Gd contrast agents can be used in hemodialysis patients if hemodialysis is carried out promptly after the examination.

Development of rotational digital angiography system--clinical value in acute pulmonary thromboembolism.

A rotational digital angiography system was newly developed by authors. During the rotation, a pulse exposure is done at every 1.25 degrees by computer control, so that 288 different projectional images can be acquired following a single injection of contrast medium. Because rotational image data can be easily reconstructed to 3-D images, more useful diagnostic informations are obtained. Rotational digital angiography was performed for 15 patients with acute pulmonary thromboembolism, and massive thromboemboli were revealed in all patients. The diagnostic usefulness of this new system has also proven to be improved in the interventional procedures. At the appropriate angle, the thrombosed vessels were clearly distinguished. Thus, as the tip of the catheter was advanced to the target site, the thrombosed lesion could be exclusively treated by interventional techniques. The device has, therefore, been found to be of great value in the diagnosis and intervention of acute pulmonary thromboembolism.