Tatsuo Kumazaki

Development of quantitative analysis method for stereotactic brain image : Assessment of reduced accumulation in extent and severity using anatomical segmentation

Through visual assessment by three-dimensional (3D) brain image analysis methods using stereotactic brain coordinates system, such as three-dimensional stereotactic surface projections and statistical parametric mapping, it is difficult to quantitatively assess anatomical information and the range of extent of an abnormal region. In this study, we devised a method to quantitatively assess local abnormal findings by segmenting a brain map according to anatomical structure. Through quantitative local abnormality assessment using this method, we studied the characteristics of distribution of reduced blood flow in cases with dementia of the Alzheimer type (DAT). Using twenty-five cases with DAT (mean age, 68.9 years old), all of whom were diagnosed as probable Alzheimers disease based on NINCDS-ADRDA, we collected I-123 iodoamphetamine SPECT data. A 3D brain map using the 3D-SSP program was compared with the data of 20 cases in the control group, who age-matched the subject cases. To study local abnormalities on the 3D images, we divided the whole brain into 24 segments based on anatomical classification. We assessed the extent of an abnormal region in each segment (rate of the coordinates with a Z-value that exceeds the threshold value, in all coordinates within a segment), and severity (average Z-value of the coordinates with a Z-value that exceeds the threshold value). This method clarified orientation and expansion of reduced accumulation, through classifying stereotactic brain coordinates according to the anatomical structure. This method was considered useful for quantitatively grasping distribution abnormalities in the brain and changes in abnormality distribution.

Three-dimensional display in staging hemodynamic brain ischemia for JET study : Objective evaluation using SEE analysis and 3D-SSP display

The Japanese EC-IC bypass trial (JET study) was established to evaluate the validity of MCA-STA anastomosis in intracranial arterial occlusive disease aiming at stroke prevention. This study must use an objective method to reliably estimate hemodynamic brain ischemia. We devised a method of objectively classifying the severity of hemodynamic ischemia using quantitatively analytical and display software, stereotactic extraction estimation for stereotactic brain coordinates and three-dimensional stereotactic surface projections (3D-SSP). We analyzed data from 16 patients registered in the JET study. Our method offers quantitative information and 3-dimensional displays of the CBF at rest and after Diamox challenge, vascular reserve and the severity of the hemodynamic brain ischemia. We compared the maximal projection counts with ROI data from tomographic images in the anterior commissure-posterior commissure plane. The maximal counts data correlated closely with the ROI data of rest and with Diamox SPECT images (both p < 0.0001). The slopes of the linear regression line were 1.15 and 1.12, respectively. The results of this study indicated that our method could simply and objectively evaluate the severity of impaired brain circulation. This procedure should support the evaluation of hemodynamic ischemia in the JET study although validation is required by several institutions using more study subjects.

Development of respiratory gated myocardial SPECT system

BackgroundThe superposition of the diaphragm and abdominal structures on the inferior wall of the left ventricle has often distorted single photon emission computed tomography (SPECT). We developed a respiratory gated SPECT (RGS) system to diminish artifacts caused by overlap between the inferior wall and upper abdomen and have validated its feasibility for clinical use.Methods and ResultsA 2-detector SPECT system equipped with a respiratory monitor based on impedance plethysmography and an original triggering apparatus was used for RGS in 7 healthy male volunteers. A pulse triggered 100 ms after every expiratory peak was processed in a SPECT system as well as an electrocardiogram (ECG) gating pulse. Inspiratory and expiratory frames were determined using the respiratory curve derived from fluctuation of the gall bladder uptake. Both sets of images were reoriented into short-axis and vertical long-axis slices. For quantification, data were reconstructed into polar plots and count density estimated in 9 myocardial segments. The mean percentage uptake of inferior segments at inspiration was significantly greater than that at expiration (81±8.3 versus 76±7.1; P<.0001). The inferior-lateral activity ratio improved from 0.78 at expiration to 0.81 at inspiration (P<.01). The coefficient of variance for each segment of inspiratory data was significantly smaller than that at expiration, indicating improved homogeneity of tracer distribution. The lowest cutoff threshold of the tomograms to separate the inferior uptake from that of the upper abdomen was significantly lower at inspiration than at expiration, suggesting smaller scatter from abdominal structures on inspiratory images.ConclusionsRGS yielded improved tracer uptake of the inferior wall in healthy male subjects and may be suitable as an alternative method for attenuation and scatter correction. However, further clinical validation is needed.

Radiotherapy for osseous metastases from hepatocellular carcinoma: a retrospective study of 57 patients

Objective:We undertook to evaluate the therapeutic effects of radiotherapy in patients with bone metastases from hepatocellular carcinoma (HCC), identify prognostic factors, and find an optimum radiation schedule.Methods:We retrospectively analyzed the clinical records of 57 patients (99 sites) with painful bone metastases from HCC from December 1978 to March 1997. Their ages ranged from 51 to 82 yr (mean, 62 yr), and the male:female ratio was 49:8. Among them, there were nine patients (16%) with metastases to other organs. Twenty patients (35%) had a solitary bone metastasis and 37 (65%) had multiple bone metastases. The total radiation dose ranged from 20 to 65 Gy (mean, 43 Gy) and that of the Time, Dose, and Fractionation Factor (TDF) values (per explanation given in text) ranged from 35.2 to 118.2 (mean, 73.2).Results:Pain relief was obtained for 83.8% (83/99) of bone metastases from HCC. Those with a TDF value of ≥ 77 (a TDF value of 77 is nearly equal to 48 Gy administered in fractions of 2 Gy each daily or 39 Gy administered in fractions of 3 Gy each daily), responded better than those with a TDF value of < 77 (p < 0.05). Overall, the median survival time from the start of radiotherapy was 179 days (6 months). Patients with a solitary bone metastasis and those without metastases to other organs had a better prognosis (p < 0.05 for both subgroups).Conclusions:Radiation therapy was effective for bone metastases from HCC, especially for those treated with a TDF value of ≥ 77.

Long-Term Results of Partial Splenic Artery Embolization as Supplemental Treatment for Portal-Systemic Encephalopathy

OBJECTIVES:To present long-term results of angiographic partial splenic artery embolization (PSE) as a supplemental treatment of portal-systemic encephalopathy.METHODS:Twenty-five patients with portal-systemic encephalopathy were divided into two groups: 14 patients underwent transportal obliteration and/or balloon-occluded retrograde transvenous obliteration (BRTO) of portal-systemic shunts (PSS), followed by PSE (PSE(+) group), and 11 patients underwent only transportal obliteration and/or BRTO of PSS (PSE(−) group).RESULTS:Portal venous pressures pretreatment was similar to posttreatment in the PSE(+) group, but lower than posttreatment in the PSE(−) group. Serum ammonia levels were higher at pretreatment than at 1 wk posttreatment in both groups, but the levels in the two groups were similar at pretreatment, 1 wk, 3 months, 3 yr, 4 yr, and 5 yr posttreatment. However, serum ammonia levels were lower in the PSE(+) group than in the PSE(−) group 6 months, 9 months, 1 yr, and 2 yr posttreatment. Grades of encephalopathy were higher at pretreatment than at 1 wk posttreatment in both groups, but the levels in the two groups were similar at pretreatment, 1 wk, 2 yr, 3 yr, 4 yr, and 5 yr posttreatment. However, grades of encephalopathy were lower in the PSE(+) group than in the PSE(−) group 3 months, 6 months, 9 months, and 1 yr posttreatment.CONCLUSIONS:Obliteration of PSS followed by PSE benefit patients with portal-systemic encephalopathy.

Single-shot diffusion-weighted echo-planar imaging of normal and cirrhotic livers using a phased-array multicoil

Single-shot spin-echo diffusion-weighted echo-planar imaging using a phased-array multicoil was performed to distinguish between normal and cirrhotic livers. Sets of 6 images with different b-values were acquired with breathholding. Significant differences were observed between controls and cirrhosis cases in the signal ratios when the b-value was 383 s/mm2, and apparent diffusion coefficients.

Retroperitoneal bronchogenic cyst: CT and MR imaging.

Retroperitoneal bronchogenic cysts are extremely rare congenital anomalies that represent malformations of the embryonic foregut and are morphologically expressed as maldevelopments of the respiratory system. Because of the low prevalence of these tumors, their imaging features have seldom been described. We present the computed tomographic and magnetic resonance imaging findings of a case of retroperitoneal bronchogenic cyst.

Management of Pancreaticoduodenal Artery Aneurysms: Results of Superselective Transcatheter Embolization

OBJECTIVE The purpose of our study was to assess the efficacy of transcatheter arterial embolization for pancreaticoduodenal artery aneurysms. CONCLUSION We concluded that transcatheter arterial embolization is the initial and definitive therapeutic choice for pancreaticoduodenal artery aneurysms, with a possible option to perform surgery after embolization.

Three-dimensional CT angiography of intracranial vasospasm following subarachnoid haemorrhage

Abstract We evaluated the usefulness of three-dimensional CT angiography (3D-CTA) in the diagnosis of intracranial vasospasm following subarachnoid haemorrhage (SAH) in 13 patients suspected of having vasospasm on clinical grounds. The intracranial vessels were clearly shown by 3D-CTA in 12 patients. 3D-CTA revealed spasm in the vessels of nine patients. Catheter angiography performed in seven of these patients immediately after 3D-CTA confirmed vasospasm. A low-attenuation area was seen on CT in the other two patients, representing an ischaemic lesion due to the spasm. In nine patients, a second 3D-CTA was performed using the same technique 1 week after the first, showing no vasospasm. Initial 3D-CTA revealed no vasospasm change in three patients. Following 3D-CTA, one of these had conventional angiography, which also demonstrated no spasm.

Chondroblastoma of the temporal bone

A rare case of chondroblastoma arising from the temporal bone that occurred in a 60-year-old woman is reported. The tumor appeared well demarcated and osteolytic on the radiographs. CT scan clearly depicted marginal and central calcification in the tumor. MR imaging demonstrated two components in the tumor: a solid component with predominantly low signal intensities on both T1- and T2-weighted sequences, and a multilocular cystic component with T1- and T2-elongation and fluid-fluid levels on the T2-weighted images. Postcontrast MR imaging revealed marked enhancement in the solid component and the septa of the cystic component.