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Purpose: This paper uses film dosimetry to investigate the relationship between multiple scan parameters of multidetector CT with automatic exposure control (AEC) and the surfacedose distribution produced on a chest phantom.Methods: The characteristics of the film used in the film dosimeter were evaluated with regard to linearity, relative film response, and directional dependence. Measurements with an ionization chamberdosimeter and a water phantom were used to evaluate the accuracy of the film dosimetermeasurements and to validate the dose profile measurements while changing the tube current, detector dimensions and pitch. When using AEC, the surfacedose distribution on the chest phantom was analyzed while changing the detector dimensions and pitch.Results: The linearity, relative film response, and directional dependence of the film were established. The measurement difference between the film dosimeter and ionization chamberdosimeter was within ±5% and the dose profile measurement results were validated. It was found that the surfacedose distribution changed helically in the direction of the body axis depending on the scan parameters and the phantom.Conclusions: Using a film dosimeter, the relationship between various multidetector CT scan parameters and the surfacedose distribution on a chest phantom was investigated and clarified.

The objectives of this study were to examine the reproducibility of the MEGA‐editing J‐difference technique and to determine the normal variation in the γ‐aminobutyric acid (GABA) level depending on the cerebral region and its fluctuation according to the menstrual cycle as baseline data for clinical application. The participants consisted of 15 normal adult volunteers (eight men and seven women), and all measurements were repeated twice in all participants. The MEGA‐editing pulses were incorporated into point‐resolved spectroscopy on a 3 T instrument to obtain the J‐difference editing spectra from a voxel located in the lentiform nuclei (LN), left frontal lobe (FL), and anterior cingulate cortex (AC). The GABA levels in the gray matter (GM) were compensated by the fraction ratios of the gray and white matters and cerebrospinal fluid in the measurement volume. The extent of the variation in GABA was almost the same as that observed in the major metabolites, and its reproducibility was also maintained (intraclass correlation coefficient > 0.7). GABA level was highest in LN and lowest in AC. A difference in the GABA level between the follicular and luteal phases of the menstrual cycle was found in both LN and FL, but not in AC. This technique showed the differences in the GABA levels in the GM and the region‐specific decrease in the GABA levels during the women's luteal phase. Hum Brain Mapp, 2011. © 2010 Wiley‐Liss, Inc.

Purpose : The purpose of this study was to evaluate the usefulness of thick slab minimum intensity projection (MinIP) as a follow-up method in patients with pulmonary emphysema. This method was used to determine the presence or absence of changes over time in the lung field based on multi-detector-row CT (MDCT) data. Methods : Among pa- tients diagnosed with pulmonary emphysema who underwent 16-MDCT (slice thickness, 1 mm) twice at an interval of 6 months or more, 12 patients without changes in the lung field and 14 with clear changes in the lung field were selected as subjects. An image in- terpretation experiment was performed by five image interpreters. Pulmonary emphy- sema was followed up using two types of thick slab MinIP (thick slab MinIP 1 and 2) and multi-planar reformation (MPR), and the results of image interpretation were evaluated by receiver operating characteristic (ROC) analysis. In addition, the time required for image interpretation was compared among the three follow-up methods. Results : The area under the ROC curve (Az) was 0.794 for thick slab MinIP 1, 0.778 for the thick slab MinIP 2, and 0.759 for MPR, showing no significant differences among the three meth- ods. Individual differences in each item were significantly more marked for MPR than for thick slab MinIP. The time required for image interpretation was around 18 seconds for thick slab MinIP 1, 11 seconds for thick slab MinIP 2, and approximately 127 seconds for MPR, showing significant differences among the three methods. Conclusion : There were no significant differences in the results of image interpretation regarding the pres- ence or absence of changes in the lung fields between thick slab MinIP and MPR. How- ever, thick slab MinIP showed a shorter image interpretation time and smaller individual differences in the results among image interpreters than MPR, suggesting the usefulness of this method for determining the presence or absence of changes with time in the lung fields of patients with pulmonary emphysema. J. Med. Invest. 58 : 175-179, August, 2011

The aim of this study was to evaluate distortion of the tabletop in a diagnostic positron emission tomography-computed tomography (PET-CT) system to determine its suitability for planning radiotherapy positioning.Distortion of the tabletop was compared among PET-CT, lineac CT, and CT simulator systems. A phantom or angiography catheter was fixed to the tabletop and imaged after iron plate weight loading. The acquired images were analyzed using radiotherapy planning software. Distortion of the tabletop was measured based on the displayed coordinates.Sinking represented the greatest distortion of the tabletop in all systems. Using the same baseline, the maximum sinking were -0.4, -0.2, and +0.4 cm, respectively. The distortion of the tabletop in the PET-CT system was more similar to that in the lineac CT than in the CT simulator system.Distortion of the tabletop in a diagnostic PET-CT system may be within the acceptable range to allow its use for planning radiotherapy positioning.

Objective The purpose of this study was to introduce a novel customized intraoral mold treatment for maxillary gingival carcinoma (UGC). Study design Two patients with UGC were treated as salvage therapy using this technique. The mold was designed to keep normal soft tissues adjacent to the tumor away from the radioactive source as much as possible, and it was shielded by lead. The radiation dose on the buccal mucosa and tongue was measured at the inner and outer surfaces of the intraoral mold before starting high-dose-rate brachytherapy by the remote afterloading system, and was reduced to almost one tenth. Results The patient had no recurrence and no severe adverse effects on the normal soft tissue adjacent to the tumor until the end of the follow-up period. Conclusion High-dose-rate brachytherapy using the novel customized intraoral mold might be a treatment option of not only salvage therapy, but definitive therapy of UGC.

The preoperative evaluation of venous thromboembolism (VTE) is important to avoid complications, because VTE is often induced by orthopedic surgery. We focused on radioisotope venography (RIV) using 99mTc-macroaggregated human serum albumin, examining orthopedic patients. We conducted 34 examinations in 33 patients who were referred for RIV and lung perfusion scintigraphy for the pre-orthopedic operative evaluation of VTE. Two board-certified (one nuclear medicine board-certified) radiologists interpreted the images based on the following: (1) flow defect of the lower extremities; (2) interruption of flow; (3) irregular or asymmetric filling of the deep vein (low flow); (4) presence of collateral vessels; and (5) abnormal RI retention on delayed-phase images. Scoring was based on a 5-point scale, and more than 2 points was considered VTE positive. Abnormal findings were noted in 27 of the 34 examinations performed in the 33 patients and normal findings in the other 7 examinations. According to the RI score, 21 patients were classified into the VTE-positive group and 12 into the VTE-negative group. Surgery was canceled because of advanced age and respiratory dysfunction in 2 of the 21 patients in the VTE-positive group. Of the 19 patients who underwent surgery, an IVH filter was placed before surgery in 2 and anticoagulant treatment with heparin and warfarin was initiated on the day of surgery in 12 to prevent postoperative VTE, and only one of the patients receiving anticoagulant treatment developed PTE after surgery. Surgery was canceled due to advanced age and at patient’s request in 2 of 12 patients in the VTE-negative group. Anticoagulant treatment with heparin/warfarin was performed to prevent postoperative VTE in only 3 patients: one with a past medical history of pulmonary infarction, one with atrial fibrillation, and one suspected of having antiphospholipid antibody syndrome. No patient in the VTE-negative group developed VTE after surgery. The preoperative identification of patients with VTE by RIV might be useful for perioperative management and the evaluation of preventive measures against postoperative VTE.

Purpose: Radiographic film is generally used for inspection of dose distribution in intensity modulated radiation therapy (IMRT) at many institutions. However, the distribution of filmless systems can be expected to be used increasingly in the future. Therefore, we confirmed the utility of radiochromic film by comparing it with radiographic film that does not need an automatic processor. Result: Difference in does measured by radiographic film and radiochromic film tended to increase in the low does area, but it was limited in a range of 1.5%. Conclusion: When the dose distribution was verified in a highly accurate radiation therapy such as IMRT, the results suggested that radiochromic film can be useful in addition to radiographic film.

We studied the lumbar spines of 117 adults (39 women and 78 men) with spondylolysis unrelated to low back pain using multidetector computed tomography (CT). Of the 117 subjects with spondylolysis, including five with multiple-level spondylolysis, there were 124 vertebrae with spondylolysis. In adult lumbar spines with unilateral spondylolysis, there was no significant difference between the incidence of spondylolisthesis in female and male subjects. However, in those with bilateral spondylolysis, there was a significantly higher incidence of spondylolisthesis in female subjects (90.9%) than in males (66.2%). Furthermore, females with bilateral spondylolysis had significant more slippage than males. Lumbar index and lumbar lordosis were not significantly different between male and female subjects, and did not significantly correlate with slippage. In conclusion, to treat acute spondylolysis in adolescents, it is important to obtain bony union at least unilaterally, especially in female subjects, to prevent further slippage.

Advanced imaging techniques, including diffusion tensor imaging (DTI), perfusion-weighted imaging (PWI), and magnetic resonance spectroscopy (MRS) can provide more information than that regarding anatomy. These techniques have been commonly used in the clinical field and recently been shown useful in diagnosing brain tumors, especially in cases difficult to specify using conventional imaging. Differentiation requires more than attention to each advanced image. Diagnostic accuracy improves by combining information from MRS with that from other sequences, such as maps of apparent diffusion coefficient (ADC) and fractional anisotropy (FA) generated from DTI and of cerebral blood volume (CBV) generated from PWI. We show clinical applications of advanced imaging techniques, combined MRS, for brain tumor.

Purpose. To evaluate 18F-fluorodeoxyglucose (FDG) uptake and the pathological risk category of gastrointestinal stromal tumors (GISTs), and to investigate the possibility of determining the pathological risk category by positron emission tomography/computed tomography (PET/CT). Patients and Methods. We undertook 29 PET/CT studies in 20 patients with GISTs. Eleven of the 20 patients underwent PET/CT prior to therapy, with three of these also undergoing follow-up PET/CT after operation or imatinib therapy. Results. All eleven lesions imaged before treatment were FDG-positive on PET/CT. Seven of these eleven primary lesions were categorized as high risk and the other four primary lesions were categorized as low or intermediate risk. There was a significant difference between the maximum standardized uptake value (SUVmax) of the primary lesions categorized as high risk (11.8 3.15) and that of the primary lesions categorized as low and intermediate risk (2.88 0.47) (p 0.001). Recurrent tumors were also shown as FDG-positive. Conclusion. Primary GISTs and recurrent tumors can be detected by PET/CT. Our study suggests that the degree of FDG uptake is a useful indicator of risk category. In addition, PET/CT is probably useful for follow-up examinations of GIST after operation or imatinib therapy.

Background: The purpose of this study was to determine the incidence and clinical correlation of intracranial hemorrhages (ICHs) detected by 3-tesla gradient echo T2*-weighted images after intravenous recombinant tissue plasminogen activator (rt-PA) administration. Methods: We included 43 consecutive patients with anterior-circulation ischemia who underwent MRI studies before and after thrombolysis. Each hemorrhage was classified as a hemorrhagic infarction (HI) or parenchymal hemorrhage (PH) according to the European Cooperative Acute Stroke Study definition. The clinical outcome was defined as an improvement (≧4-point reduction) or deterioration (≧4-point increase) based on a comparison between the initial and the 30-day NIHSS scores. Results: The incidence of ICHs was 58%, and the HI rate was 52%; both were higher than the rates reported in the literature. Most of the patients with HI improved clinically, and these patients had second MRAs that showed recanalization. None of the patients with PH demonstrated improvement. Conclusions: Three-tesla MRI may reveal a higher frequency of HI type hemorrhages than lower-field MRIs, and HI may be a predictor of good recovery by reflecting the presence of recanalization. The rate of PH in our study was low compared to other studies, probably due to the lower dosage of rt-PA.

Ovarian metastasis from malignant melanoma is rare and usually appears as a solid ovarian mass. We report a case of ovarian metastasis from cutaneous malignant melanoma that proved to be a diagnostic dilemma. The ovarian metastasis exhibited a multilocular cystic appearance on magnetic resonance imaging, mimicking a mucinous ovarian tumor with massive ascites.

Objective: The objective was to determine whether diffusion-weighted imaging (DWI) might be useful in differentiating uterine leiomyomas exhibiting hyperintensity on T2-weighted images from malignant lesions. Methods: Thirty-four uterine myometrial lesions including 7 malignant tumors and 27 leiomyomas (6 cellular leiomyomas [CLM] and 21 degenerated leiomyomas [DLM]) were evaluated. The apparent diffusion coefficients (ADC) in cellular portions of the lesions were measured (10 -3 mm 2 /s). Results: All malignant tumors showed high signal intensity on DWI with low ADC (mean [SD], 0.79 [0.26]), which was significantly lower (P < 0.01) than that in benign leiomyomas (1.51 [0.33]). The ADC in CLM (1.18 [0.16]) was significantly lower (P < 0.01) than that in DLM (1.60 [0.30]) and higher (P < 0.05) than that in malignant tumors. Conclusions: It was difficult to differentiate malignant tumors from leiomyomas on the basis of signal intensity on DWI; however, the ADC measurement may be helpful to distinguish malignant tumors, CLM, and DLM.

The purpose of this study was to estimate the gamma-aminobutyric acid (GABA) and glutamate plus glutamine (Glx) concentrations in the cortical tubers of patients with tuberous sclerosis complex (TSC) using the MEGA-editing J-difference method and a stimulated echo-acquisition mode with a short echo time, and to determine which abnormality was more dominant between GABA and Glx in patients with TSC with epilepsy. This study included six patients with TSC (mean age, 4.3 years) and seven control subjects (mean age, 4.8 years). Measurements were obtained with a three-Tesla apparatus and postprocessing was conducted with an LCModel. The GABA level in the cortical gray matter (cgGABA) was calculated as a result of segmentation in voxels and from the literature values for gray and white matter ratios for GABA. Increased GABA and myo-inositol (mI) concentrations and a decreased N-acetyl aspartate (NAA) concentration were observed in the cortical tubers. The cgGABA level, and cgGABA/NAA and cgGABA/Glx ratios were also higher in patients with TSC than in control subjects. No significant difference was found in Glx concentration between patients with TSC and control subjects. Although the number of patients with TSC in this study was small, the increase in GABA and no significant change in Glx were consistent with previous neurochemical studies and support the hypothesis that brain GABA plays a key role in the pathophysiology of epilepsy during the process of neuronal development.

Study design Epidemiological analysis using CTs. Objective To investigate the true incidence of lumbar spondylolysis in the general population in Japan. Summary of background data Although there have been several reports on the incidence of lumbar spondylolysis, they had some weakness. One of them concerns the subjects investigated, because the incidence of lumbar spondylolysis varies considerably, and some patients are asymptomatic. In addition, most of the past studies used plain radiograph films or skeletal investigation. Therefore, the past reported incidence may not correspond to that of the general population. Methods We reviewed the computed tomography (CT) scans of 2000 subjects (age: 20-92 years) who had undergone abdominal and pelvic CT on a single multidetector CT scanner for reasons unrelated to low back pain. We reviewed them for spondylolysis, spondylolytic spondylolisthesis, and spina bifida occulta (SBO) in the lumbosacral region. The grade (I-IV) of spondylolisthesis was measured using midsagittal reconstructions. Results Lumbar spondylolysis was found in 117 subjects (5.9%). Their male-female ratio was 2:1. Multiple-level spondylolysis was found in 5 subjects (0.3%). Among these 117 subjects, there were 124 vertebrae with spondylolysis. Of them, 112 (90.3%) corresponded to L5, and 26 (21.0%) had unilateral spondylolysis.SBO was found in 154 subjects. Of them, 25 had spondylolysis (16.2%), whereas, in 1846 subjects without SBO, 92 had spondylolysis (5.0%). The incidence of spondylolysis among the patients with SBO was significantly higher than that in subjects without SBO (Odd ratio was 3.7-fold).Of 124 vertebrae with spondylolysis, 75 (60.5%) showed low-grade (Meyerding grade I or II) spondylolisthesis, and no subject presented high-grade spondylolisthesis. Spondylolisthesis was found in 74.5% of the subjects with bilateral spondylolysis, and in 7.7% of those with unilateral spondylolysis. Conclusion The incidence of lumbar spondylolysis in the Japanese general population was 5.9% (males: 7.9%, females: 3.9%).

Objective : Imaging techniques such as CT, MRI and PET/CT have essential pre- and post-treatment roles in detecting tumors and evaluating the extension of malignant pleural mesothelioma (MPM). We sough to evaluate the advantages and limitations on FDG-PET/CT findings. Patients and Methods : We performed 13 FDG-PET/CT studies in 9 patients with MPM (8 males, 1 female, aged 51 to 84 years, 9 at the initial diagnosis, 4 fol- low up studies). We reviewed FDG-PET/CT findings of primary tumors, recurrent tumors, lymph nodes, metastasis. Results : All primary and recurrent tumors were FDG positive. The uptake patterns at initial diagnosis were ; diffuse+multi-nodular uptake pattern in 5, diffuse irregular thickened uptake pattern in 2, some focal thickened pattern in one, and a slight diffuse uptake pattern in one. Two of the 3 patients diagnosed as N0 by PET and operated on had negative lymph nodes confirmed pathologically. The other patient diagnosed as N0 by PET, who had one month of time lag between PET/CT examination and surgery, was confirmed as N2 by extrapleural pneumonectomy. In 3 patients, hilar or me- diastinal lymph nodes were difficult to distinguish from irregular pleural thickening. One patient had a FDG positive lymph node in the ipsilateral supraclavicular region confirmed as metastasis (N3). One patient had a FDG positive lymph node in the para-aortic region. Lung metastasis was seen in one patient (M1). In another patient, two focal nodular up- takes in the colon were detected and confirmed as colon polyps (pathologically Group 3- 4). At restaging, 3 of 4 patients showed diffuse+multi-nodular uptake and one patient showed multi-nodular uptake. Conclusions : The utility of FDG-PET/CT is limited for evaluation of primary tumor extension and nodal status. FDG-PET/CT is useful for detect- ing distant metastasis and for evaluating activity in supraclavicular or abdominal lymph nodes. It is also useful for identifying unsuspected diseases. J. Med. Invest. 56 : 16-20, February, 2009

Objective We report the findings of Thallium-201 chloride (201TlCl) scintigraphy and consider how to use this technique to evaluate the character of soft tissue lesions. Patients and Methods We enrolled 91 consecutive patients (45 males and 46 females, age range 8-91-years-old). Nineteen patients were malignant and 72 were benign. Patients were scanned 15 minutes (early phase) and 3 hours (delayed phase) after 201TlCl injection. More intense uptake in the lesion compared to the normal side was considered as ‘high’, the same degree of uptake was considered ‘iso’, and decreased uptake was ‘low’. The retention index (RI) was calculated in 9 patients in the malignant group and in 16 patients in the benign group. Results In malignant tumors, 15 of 19 patients showed high uptake in both the early and delayed phases. One malignant fibrous histiocytoma patient was high only in the delayed phase and 1 liposarcoma patient was high only in the early phase. Two liposarcoma patients showed an iso uptake in both phases. One of these patients was pathologically diagnosed as a myxoid type. In benign lesions, no lipoma showed increased uptake. All neurogenic tumors except for 2 demonstrated high uptake. All 3 ganglions of the lower extremities showed iso uptake. Most inflammatory diseases showed increased uptake. Clinically-considered benign patients consisted of tumorous lesions or inflammatory disease. Only 2 patients were considered ‘low’, and these were diagnosed as intramuscular hematoma and cyst. RI was variable in both malignant and benign lesions and no statistically significant difference was seen between malignant and benign lesions by t-test (p=0.72). Conclusions A high 201TlCl uptake lesion is more frequently seen in malignant tumors, but regardless of whether the tumor is benign or malignant, according to the histopathological variety, the 201TlCl uptake pattern can not be the only indicator to differentiate malignant from benign tumors. We ultimately need to evaluate the nature of tumors by a combination of several imaging techniques.

We evaluated risk factors of radiation pneumonitis (RP) after whole breast irradiation following breast-conserving surgery. Four hundred and seventy-two cases underwent whole breast irradiation with tangential field following breast-conserving surgery in our hospital, between January 2005 and April 2007. Of these cases, we performed statistical analyses for 423 breasts of 413 patients, using a pulmonary dose-volume histogram. Patient characteristics, treatment regimens and irradiation methods were included as variables in the analyses on risk factors of RP. As a result, 89 breasts of 84 cases (21%) were diagnosed with RP. The version 3.0 of the NCI Common Terminology Criteria for Adverse Events was used to evaluate the grade of pneumonitis : 77 cases (18.2%) were diagnosed as Grade 1 RP, 10 cases (2.3%) as Grade 2, and 2 cases (0.5%) as Grade 3. Multivariate analysis indicated that the significant risk factors for RP were central lung distance (CLD) (>1.8 cm) and the short axis length of the radiation field. The incidence of radiationinduced bronchiolitis obliterans organizing pneumonia (BOOP) syndrome significantly correlated only with CLD. The lung volume within the radiation field was shown to be a significant risk factor for RP and radiation-induced BOOP syndrome.

Clear-cell sarcoma (CCS) is a rare, malignant, soft-tissue tumor, which involves the extremities, particularly the foot and foot joint tendons and aponeuroses. It is morphologically similar to but histochemically distinct from malignant melanoma. CCS arising in the gastrointestinal tract has rarely been reported. The prognosis of CCS is reportedly poor because of the high incidence of metastases at the time of initial diagnosis and the high frequency of recurrence. We report a case of early-stage CCS of the small intestine detected by (18)F-fluoro-2-deoxy D-glucose Positron Emission Tomography/Computed Tomography (FDG-PET/CT) during the comprehensive examination of an inflammatory reaction. In this case, FDG-PET/CT clearly visualized the lesion, which was difficult to detect by contrast CT.

Purpose: We evaluated the usefulness of rating diffusion-weighted images (DWI) using a semiquantitative score modified from the Alberta Stroke Programme Early CT Score (ASPECTS) to predict deterioration of neurological symptoms in patients with hyperacute ischemic stroke who had undergone thrombolytic therapy with recombinant tissue plasminogen activator (rt-PA). Materials and Methods: We examined 22 patients with acute stroke (14 men, 8 women, mean age 72.5 years) treated with intravenous rt-PA. All were assessed using the National Institutes of Health Stroke Scale (NIHSS) and underwent emergent magnetic resonance (MR) imaging within 3 hours and 24 hours of stroke onset. Patients were divided into a deteriorated group (16 patients), in which NIHSS scores were increased after thrombolysis, and a non-deteriorated group (6 patients). We compared the DWI score, ASPECTS, and volume of hyperintense ischemic lesion on DWI (DWI volume) of the 2 groups and examined correlations between these scores and initial NIHSS score or DWI volume. Results: The DWI score and ASPECTS tended to be lower in the deteriorated group than the non-deteriorated group. In addition, with a cutoff value≤7, the DWI score could discriminate the deteriorated group from the non-deteriorated group with a sensitivity of 50% and specificity of 87.5%, whereas for ASPECTS, sensitivity was 50% and specificity, 81.2%. The DWI score, ASPECTS, and DWI volume had no correlation with NIHSS score but weak negative correlations with the DWI volume (P

Background: Various malignant tumors of the body show high signal intensity on diffusion-weighted magnetic resonance imaging (DWI). In the genitourinary region, DWI is expected to have a role in detecting urinary epithelial cancer noninvasively. Purpose: To demonstrate the feasibility of DWI for the diagnosis of urinary epithelial cancer with upper urinary tract obstruction. Material and Methods: Twenty upper urinary tract cancers in 16 patients were evaluated by high- b-value DWI ( b=800s/mm2). The signal intensity was visually evaluated, and the apparent diffusion coefficients (ADCs) were measured. Results: All urinary epithelial cancers showed high signal intensity on DWI. The ADC in cancerous lesions was 1.31±0.27×10−3 mm2/s, which was significantly lower than that of the lumens of the ureter or renal pelvis (3.32±0.44×10−3 mm2/s; P Conclusion: DWI is useful in the tumor detection and in evaluating the tumor extension of urinary epithelial cancer in patients with upper urinary tract obstruction.

Susceptibility-weighted MRI combines magnitude and phase information from fully velocity-compensated gradient-echo sequences and depicts as signal voids the susceptibility effects caused by local inhomogeneity of the magnetic field. Our objective, based on MRI of 60 pathologically proven ovarian cystic lesions, including 42 endometriomas and 18 nonendometrial cysts, was to evaluate hemosiderin deposition within the walls of endometriomas on susceptibility-weighted MR images. Two radiologists blinded to the final diagnosis retrospectively reviewed the images in consensus.On susceptibility-weighted MR images, punctate or curved linear signal voids along the cyst wall were observed in 39 endometriomas (92.9%) and in no nonendometrial cysts. The signal voids were more prominent on 3-T than on 1.5-T images, reflecting the higher sensitivity of 3-T MRI to magnetic susceptibility effects. Thirty-two endometriomas (76.2%) met definitive MRI criteria, that is, hyperintensity on T1-weighted images and hypointensity on T2-weighted images, and 41 endometriomas (97.6%) were correctly diagnosed with susceptibility-weighted MRI.

Background: Mass-forming chronic pancreatitis may mimic a pancreatic cancer on dynamic computed tomography (CT) and magnetic resonance (MR) imaging, and preoperative differential diagnosis is often difficult. Recently, the usefulness of diffusion-weighted MR imaging (DWI) in the diagnosis of pancreatic cancer has been reported in several studies. Purpose: To determine whether high- b-value DWI can distinguish pancreatic cancer from benign mass-forming chronic pancreatitis. Material and Methods: Twenty pancreatic cancers and four cases of mass-forming chronic pancreatitis were evaluated by high- b-value DWI ( b=800 s/mm2). The signal intensity on DWI was visually evaluated, and the isotropic apparent diffusion coefficients (ADCs) were measured. Results: All twenty pancreatic cancers showed high signal intensity (18 showed very high, two showed slightly high) on DWI. None of the mass-forming chronic pancreatitis cases showed very high intensity (three showed iso to low, one showed slightly high) on DWI. The ADCs in the pancreatic cancer and mass-forming chronic pancreatitis were 1.38±0.32×10−3 mm2/s and 1.00±0.18×10−3 mm2/s, respectively ( P Conclusion: On high- b-value DWI, most pancreatic cancers showed very high signal intensity, and may hence be distinguished from benign mass-forming chronic pancreatitis based on our preliminary results.

The aim of this study was to evaluate retrospectively the toxicity and response, bladder preservation, and survival of patients with muscle-invasive bladder cancer treated with multimodality therapy consisting of low-dose radiation therapy (RT) and concurrent intraarterial chemotherapy (IACT).. Between November 1999 and July 2005, a total of 27 consecutive, previously untreated patients with muscle-invasive bladder cancer underwent transurethral bladder tumor resection followed by concurrent low-dose RT and IACT. Patients who achieved a complete response (CR) were followed up closely without further therapy, and patients who did not achieve a CR underwent further treatment.Complete response was achieved in 22 of 27 patients (81%). Of these 22 patients, 7 developed recurrences, and 3 died of their disease. In five patients who did not achieve CR, one died from bone metastases. The 3-year overall survival rate was 81%, with a median follow-up time of 27 months; and 22 of 27 patients (81%) with a preserved bladder were tumor-free at the last follow-up. Three patients (11%) developed grade 3 acute hematological toxicity.Multimodality therapy consisting of low-dose RT and concurrent IACT for muscle-invasive bladder cancer can achieve survival rates similar to those in patients treated with radical cystectomy, with successful bladder preservation and minimal adverse effects.

Objective: To compare the enhancement of brain metastasis between 3-dimensional fast spoiled gradient recalled acquisition in the steady state (3DFSPGR) and spin echo (SE) T1-weighted imaging at 3-T magnetic resonance imaging. Methods: The subjects comprised 18 patients with 81 suspected brain metastases. Axial SE and 3DFSPGR images were obtained before and after gadoteridol injection. The signal intensity of each tumor was measured for each sequence; the enhancement and contrast rates were also calculated. Results: For equivalent slice thicknesses, the enhancement and contrast rates of the 3DFSPGR images were lower than those of the SE images (

Hypoxia-inducible factor (HIF)-2alpha, a basic helix-loop-helix (bHLH)-PAS protein, is the principal regulator of the hypoxic transcriptional response. An immunohistochemical study reported strong HIF-2alpha expression in the cytoplasm of tumor infiltrative macrophages (TIMs). Thus we assessed the expression of HIF-2alpha in human cervical cancer tissue before radiation therapy and its relationship to the clinical outcome. Seventy three patients with histologically proven primary advanced squamous cell carcinoma of the uterine cervix underwent radiotherapy in Tokushima University Hospital after biopsy specimens were taken. Among 73 specimens stained for HIF-2alpha, 53 (72.6%) exhibited HIF-2alpha immunoreactivity in the TIMs. In only 5 of 73 cases, HIF-2alpha immunoreactivity was observed in the nuclei of tumor cells. The HIF-2alpha positive cell count ratio in TIMs was associated with disease-free survival (DFS) with the worst DFS (p=0.024) being in cases in the group with a high positive cell count ratio. A high HIF-2alpha positive cell count ratio in TIMs increased the risk of local recurrence (p=0.0142). These findings might suggest that the ratio of the HIF-2alpha positive cell in TIMs may be a new predictive indicator for prognosis before radiation therapy for uterine cervical cancer.

Objectives: Study objectives were: to develop a hanging protocol for displaying digital transmission radiographic images of oral and maxillofacial regions using a dental DICOM (digital imaging and communication in medicine) viewer and a dental Web viewer; and to give information on a system that allows patients and health professionals to share image information. Methods: For the hanging protocol, alphanumeric tags were defined and used in a DICOM modality worklist. These tags consisted of layout information to display images on monitors by the type of projection method and assignment information to display images of template for intraoral full-mouth survey that were numbered and slotted according to tooth position. Tooth code and algorithm for assignment of images for intraoral full-mouth survey were determined. Expanded correspondence for viewers was used for modalities without tags. Images could be edited by quality control system. An electronic medical record (EMR) system, a radiological information s...

FDG-PET/CT is increasingly being used for staging, restaging, and treatment monitoring for cancer patients. The introduction of a PET/CT system enables both morphological and metabolic imaging to be performed in a single session. Knowledge of the normal physiologic distribution of FDG and an understanding of the clinical indications and limitations of PET/CT enable accurate diagnosis and thus a better level of care for patients.

We report three cases of vasculitis evaluated by FDG-PET/CT. Vasculitis is defined as inflammatory changes and necrosis in the aterial wall. The patients presented with non-specific symptoms such as fever up or elevated inflammatory markers. FDG-PET/CT clearly demonstrated intense FDG uptake in vessel walls. A 72-year-old female patient with a one month history of pyrexia had abnormal laboratory data suggesting an inflammatory process. FDG-PET/CT was very useful for the diagnosis of vasculitis. Steroid therapy was introduced. Normalization of laboratory data and symptomatic improvement correlated with normalization of FDG uptake in the vessels.

Objective To investigate the incidence, clinical and imaging finding of insufficiency fractures (IF) of the female pelvis following radiation therapy. Methods We reviewed the radiation oncology records of 158 patients with gynecologic malignancies who underwent external beam radiation therapy of the whole pelvis between April 1993 and March 2004. All patients underwent computed tomography (CT) scan every 6 months in follow-up after radiation therapy and magnetic resonance imaging (MRI) and radionuclide bone scan were added when the patients complained of a pelvic pain. Results Eighteen of 158 patients (11.4%) developed IF in the irradiated field with a median interval of 6 months (range 3–51) from the completion of external beam radiation therapy. The cumulative incidence of symptomatic IF at 5 years calculated with Kaplan–Meyer methods was 13%. Median age of the patients who developed IF was 70 years (range 48–88), and all of them were postmenopausal. IF occurred in the sacloiliac joints, upper limb of pubic bone, acetabulum, sacral body and 5th lumbar vertebra. Twelve of 18 patients had multiple lesions and 8 had symmetric longitudinal fracture lines parallel to the sacroiliac joints. Avoidance of weight bearing by bed rest and analgesics provided good pain relief in all patients, although symptoms lasted from 3 to 20 months. Conclusions Radiation-induced pelvic IF following radiation therapy for gynecologic malignancies were frequently observed in the postmenopausal patients within 1 year after external beam radiation therapy. Symmetric fractures of the both sacroiliac joints were the characteristic pattern of pelvic IF. Knowledge of characteristic imaging pattern of IF is essential in order to rule out the bone metastasis. Therapy recommendations are conservative with analgesics.

Purpose: OncoSeed is delivered in a sterile environment in the form of a cartridge, so it is impractical to resterilize and reload seeds after calibration. We investigated a new method using an imaging plate dosimetry system to characterize all seeds in the OncoSeed cartridge in a sterile environment. Methods and Materials: Seeds within the cartridge were placed on an imaging plate, and the imaging plate irradiated. To remove scatter radiation, and improve spatial resolution of seed images, we used X-ray parallel cross grids. The irradiated imaging plate was scanned using a Bio-imaging Analyzer System, and radioactivity intensities of seed images were given in counts. Counts could be translated to profiles, and each seed within the cartridge was analyzed. Results: Results showed a good correlation between counts and total radioactivity of the seeds within the cartridge. Thus, using a least-squares line, it was possible to characterize a cartridge with unknown apparent activity. By analyzing the profiles, it was possible not only to detect a miscalibrated seed in the cartridge from its relative difference in counts, but also to identify its position in the cartridge. No significant changes in counts were seen between sterile and nonsterile environments. Conclusion: Using an imaging plate dosimetry system, all seeds in a cartridge could be characterized in a sterile environment.

We conducted statistical parametric comparison of fractional anisotropy (FA) images and quantified FA values to determine whether significant change occurs in the ischemic region.The subjects were 20 patients seen within 24 h after onset of ischemia. For statistical comparison of FA images, a sample FA image was coordinated by the Talairach template, and each FA map was normalized. Statistical comparison was conducted using SPM99. Regions of interest were set in the same region on apparent diffusion coefficient (ADC) and FA maps, the region being consistent with the hyperintense region on diffusion-weighted images (DWIs). The contralateral region was also measured to obtain asymmetry ratios of ADC and FA.Regions with areas of statistical significance on FA images were found only in the white matter of three patients, although the regions were smaller than hyperintense regions on DWIs. The mean ADC and FA ratios were 0.64 +/- 0.16 and 0.93 +/- 0.09, respectively, and the degree of FA change was less than that of the ADC change. Significant change in diffusion anisotropy was limited to the severely infarcted core of the white matter.We believe statistical comparison of FA maps to be useful for detecting different regions of diffusion anisotropy.

Purpose Recent years, CT on rail system was reported to be useful as a tool for image-guided radiotherapy (IGRT). This system was clinically developed with the aim of stereotactic irradiation (STI) for brain, lung, liver, prostate and other sites. Quality assurance and quality control (QC) is an important issue in CT on rail system to assure geometric accuracies. The purpose of this study is to estimate the geometric accuracies of our CT on rail system using a detachable micro-multi leaf collimator (mMLC) with new type radiochromic films. Carrying out our original QC program, translational errors, setup reproducibility, beam misalignment and beam characteristics were evaluated. Methods and materials We have studied with CT on rail system (FOCAL unit, Toshiba Medical systems, Tokyo, Japan) and mMLC unit (Accuknife, Direx Inc., Tokyo, Japan). We have developed original alignment phantom and small steel markers (2 mm phi) were implanted on its surface at certain intervals. Firstly, we have evaluated the accuracy of self-moving CT gantry and CT resolutions for cranio-caudal directions by changing slice thickness. And then using the phantom, we have measured the accuracy and reproducibility of geometric isocenter of the linac side and the CT gantry side by scanning the phantom. We have also measured the geometric changes of the common treatment couch by weight-loaded test (up to 135 kgw). To estimate dosimetric and geometric accuracies with the mMLC unit, the misalignment of the beam axes (gantry, collimator and couch rotation axis), mMLC leaf positions, and dose distributions for the verification plan were measured with new type GafChromic films (GafChromic-RTQA, ISP Inc., USA) and cylindrical phantom. The dose characteristics of the GafChromic film were also evaluated. Results The reproducibility of the self-moving CT gantry have a good agreement within 1 mm. Weight-load test have shown a good reliability within 2 mm at the common treatment couch. The translational precision of the common treatment couch was 0.0 +/- 0.1 mm at linac side and -0.2 +/- 0.5 mm at CT gantry side. The misalignments of beam axes have been kept within 0.4 mm at maximum. Gap test have shown the accuracies of the mMLC leaf positions, which is needed to keep within 1 mm by a routine calibration. Conclusions To practice quality control program for the FOCAL unit and the mMLC unit is essential for a regular interval to reduce systematic errors. New type radiochromic film would be useful for a verification tool as alternative to conventional film.

Purpose: To evaluate the hemodynamic changes of liver cirrhosis in the rat and investigate the relationship between hemodynamic changes and properties of fibrotic change in the liver. Materials and Methods: Three rats with cirrhosis induced by thioacetamide (TAA), three with disease induced by carbon tetrachloride (CCl4), and three with no treatment were measured on dynamic MRI using a 1.5T scanner. Compartment and moment analysis were used to quantitate hemodynamic changes. Results: Compartment model analysis showed that increased transition speed from vessels to the liver correlated with grade of liver fibrosis. Moment analysis demonstrated that decrease of area under the curve (AUC), mean residence time (MRT), variance of residence time (VRT), half life (T1/2) and increased total clearance (CL) correlated with grade of liver fibrosis. Conclusions: Hemodynamic changes in injured fibrotic liver may be influenced by the grade of fibrosis. Compartment model and moment analysis may be useful for evaluating hemodynamic changes in injured liver.

Transforming growth factor-β (TGF-β) family members regulate a variety of cellular functions and play important roles in cell differentiation. Activin receptor-like kinase 7 (ALK7), a receptor for TGF-β family members, was initially cloned from rats as an orphan receptor and has been recently shown to be a type I receptor for nodal, activin B and activin AB. ALK7 is expressed not only in neurons, but also in insulin-producing islet β cells and white and brown adipose tissues; however, the specific functions of ALK7 in these tissues are not known. In order to test whether ALK7 is involved in adipocyte differentiation, we analyzed its expression during adipocyte differentiation. ALK7 expression was detected in the late phase of adipocyte differentiation by reverse transcriptase-polymerase chain reaction (RT-PCR), Western blotting and immunofluorescence staining in 3T3-L1 cells. We also detected the expression of ALK7 by RT-PCR in stromal vascular fraction (SVF) cells. These results indicated that ALK7 is a novel marker specifically expressed during the late phase of adipocyte differentiation. Furthermore, our results suggest the possible involvement of nodal or activin B in adipocyte differentiation. J. Med. Invest. 53: 238-245, August, 2006

The aim of this study was to evaluate the impact of FDG-PET in the management of patients with salivary gland malignancy. We performed 45 FDG PET studies in 31 patients with salivary malignant tumors, using PET (33 studies) and PET/CT (12 studies). Patients comprised 21 males and 10 females with a mean age of 69 y (range 38–89). Nineteen patients had a single study, ten patients had 2 and two patients had 3 studies. Twelve studies were performed for initial staging and 33 studies for restaging. Four patients of the initial staging group were restaged with PET after therapy. Histology consisted of 8 adenocarcinomas, 8 squamous cell carcinomas, 4 adenoid cystic carcinomas, 4 carcinoma ex pleomorphic adenomas, 2 mucoepidermoid carcinomas, 2 poorly differentiated carcinomas, 1 salivary duct carcinoma, 1 lymphoepithelial carcinoma and 1 melanoma. PET findings were reviewed with the clinical and radiologic findings and the impact of PET on staging and patient management was determined. In the initial staging group, all 12 primary lesions (100%) showed positive FDG uptake (5 squamous cell carcinomas, 2 adenocarcinomas, 2 poorly differentiated carcinomas, 1 carcinoma ex pleomorphic adenoma, 1 salivary duct carcinoma, 1 lymphoepithelial carcinoma). Three patients (25%) had FDG positive distant disease (liver, bone, lymph nodes); surgery was canceled and therapy changed to chemoradiation. One patient (9%) with no FDG uptake in the neck nodes avoided a planned neck dissection. In the restaging group (33 studies in 23 patients), 5 patients (22%) had FDG positive distant disease, which changed the treatment from surgery to chemoradiation or other. A second primary lesion was detected in one patient (4%). One patient (4%) with clinically suspected recurrence was able to avoid other invasive procedures because of the negative PET. Overall, FDG PET resulted in a major change in management in 11 of 31 patients (35%). This study shows that FDG PET has a significant impact on the management of patients with salivary malignant tumors in both the initial staging and restaging.

Objective: There has been reports on the usefulness of diffusion tensor imaging (DTI) about age-or disease-related degradation. DTI is generally evaluated by the region of interest (ROI) methodology. In this study, we applied a statistical way using Statistical Parametric Mapping (SPM) to assess normal aging by DTI and compared results of these two methods.Methods: Ten young and ten senior normal volunteers were examined. On SPM, tensor images were changed into normalized tensor images. They were compared between the two groups by t-test.Results: In the senior group, fractional anisotropy (FA) values were higher on the basal ganglia, cingulated gyrus and other cortical gray matter, lower in the corona radiata, internal capsule, centrum semiovale and corpus callosum by using SPM. In the ROI method, the results were almost compatible except in the brain periphery.Conclusions: Aging changes on water diffusion anisotropy was clearly shown by SPM method which would be useful to evaluate change of water diffusion anisotropy without operator bias even in clinical setting instead of ROI measurement. J. Med. Invest. 52: 186-190, August, 2005

The endometrial cavity may demonstrate various imaging manifestations such as normal, reactive, inflammatory, and benign and malignant neoplasms. We evaluated usual and unusual magnetic resonance imaging (MRI) findings of the uterine endometrial cavity, and described the diagnostic clues to differential diagnoses. Surgically proven pathologies of the uterine endometrial cavity were evaluated retrospectively with pathologic correlation. The pathologies included benign endometrial neoplasms such as endometrial hyperplasia and polyp, malignant endometrial neoplasms such as endometrial carcinoma and carcinosarcoma, endometrial-myometrial neoplasm such as endometrial stromal sarcoma, pregnancy-related lesions in the endometrial cavity such as gestational trophoblastic diseases (hydatidiform mole, invasive mole and choriocarcinoma) and placental polyp, myometrial lesions simulating endometrial lesions such as submucosal leiomyoma and some adenomyosis, endometrial neoplasms simulating myometrial lesions such as adenomyomatous polyp and endometrial lesions arising in the hemicavity of a septate/bicornate uterus, and fluid collections in the uterine cavity (hydro/hemato/pyometra). It is important to recognize various imaging findings in these diseases, in order to make a correct preoperative diagnosis.