Evaluation of CT Functional Imaging in Patients with Cerebral Ischemia

CT functional imaging makes it possible to demonstrate the time course of contrast enhancement as visual images by assigning a shade of gray to each pixel within a scan plane depending on the value of the selected transit parameter at the pixel. In order to assess the clinical usefulness of this method, CT functional images were created from dynamic CT scans of 14 patients with ischemic cerebrovascular diseases who showed negative or equivocal findings on the first conventional CT examination. Diagnostic abilities of CT functional images, especially of the first moment (M1-functional images), were tested by the prospective analysis of clinical course and subsequent CT studies, and were compared with those of conventional and dynamic CT scans. Conventional CT scans could only suggest the existence of abnormality in one of the 14 cases. Visual inspection of dynamic CT images and analysis of time-density curves were helpful in detecting the abnormal blood flow in 3 of the 14 cases. M1-functional images could reveal the existence and the extent of ischemic lesions responsible for symptoms in 12 of the 14 cases. CT functional imaging was found to be a useful technique for the detection of cerebral ischemia and for the early diagnosis of cerebral infarction

Functional Imaging of Hepatic Masses Using Computed Tomography

In order to assess the usefulness of CT functional images, twenty one cases with liver masses were studied. We tried to minimize the motion artifacts by immobilizing the patients with a girdle in performing dynamic CT scans, and by discarding some of the segmented images with serious artifacts before constructing functional images. The qualities of images obtained were considered satisfactory. Of the several transit parameters obtained from the dynamic CT scans, we found the first moment (Ml) to be most useful and the effectiveness of Ml-functional images were studied. In all cases with hepatocellular carcinomas (12 cases) and intrahepatic cholangiocarcinomas (2 cases), the Ml-functional images showed the viable portions of tumors as accumulations of dark pixels reflecting rapid transit times due to arterial blood supply. In three cases with hepatic cavernous hemangiomas, the lesions were represented as bright areas with a well-defined border. In two cases with hepatic abscesses, the Ml-functional images suggested the presence of hyperemia in the surrounding tissue as demonstrated by bright pixels around the lesions. CT functional imaging was proved to be useful for evaluating the circulatory dynamics of contrast material and the differential diagnosis of liver tumors when conventional or dynamic CT studies failed to provide enough information. This technique enabled overall analysis of time-density curves for the entire plane of an image semiautomatically and without the subjective maneuver of setting ROI's (regions of interest)

Multiple Hepatic Lesions During Acute Leukemia Remissions

The US and CT manifestations of multiple small hepatic lesions of 15 patients during their remissions following chemotherapy for acute leukemia were reviewed. Liver biopsies established the diagnoses in 5 of the 15 patients. Despite their remissions, two cases had leukemic involvement. Others had microabscesses, 2 due to candida and 1 due to peptostreptococcus. Ultrasonographically, the microabscesses and leukemic involvement in the liver consisted of multiple round hypoechoic and target-like masses. With CT, these appeared as multiple zones of diminished attenuation. Only distal acoustic enhancement with US could differentiate these disease processes

Intraarterial Digital Subtraction Angiography for Evaluating Hepatic Tumors

The intraarterial digital subtraction angiography (DSA) of 52 patients with hepatic tumors was retrospectively reviewed. In 18 patients, intraarterial DSA was compared with conventional angiography. With DSA, the displacement of arteries, arterial encasement and tumor vessels were equally well identified on comparison with conventional angiography. DSA was superior to conventional angiography in demonstrating tumor stains. The diagnostic imaging capability of DSA was studied in 52 patients. In the majority of cases, DSA imaging was diagnostic for visualizing the tumors and determining their extent. The differential diagnosis of hepatic tumors was made without difficulty. Demonstration of the portal venous system was excellent using smaller quantities of contrast material and slower injection rates than by the conventional angiography. The major advantage of DSA is excellent contrast resolution and ability of the real-time information. DSA was therefore useful for evaluating hepatic tumors

Ultrasonographic Manifestations of Liver Abscesses : An Experimental Study

The livers and portal veins of 3.0-3.5 kg male rabbits were inoculated with S. aureus, and E. coli combined with B. fragilis to induce liver abscesses and relate ultrasonographic images to pathologic findings. There were no morphological differences between those of S. aureus and the anaerobic infections. Small abscesses were generally echogenic, and consisted histologically of polymorphs, coagulation and granulation tissue. These irregularly-margined structures with liquefective necrosis had "bull's-eye" appearances. So-called "established abscesses" with hypoechoic surroundings were also observed, with central liquefective necrosis, polymorphs and granulation tissue peripherally. The peripheral echo-free halos were attributed to coagulation necrosis

Analysis of External Radiotherapy for Localized Prostatic Cancer

From 1968 to 1986, 62 patients with Stage C prostatic cancer were treated at Hiroshima University Hospital. Of these, 33 patients were treated by castration plus DES-DP (hormone therapy alone) from 1968 to 1975. Twenty-nine patients were treated by definitive radiotherapy after castration (combined therapy) from 1976 to 1986. Although the expected survivals of both periods were comparable, the survival rate of the combined therapy group was significantly higher than that of hormone therapy-alone group (five-year; 78.3% vs. 46.9% and ten-year; 52.2% vs. 0%, p < 0.05). Eight of the 29 patients in the combined therapy group died. Four died of prostatic cancer and four of other diseases. Total dose was 6000 cGy or less in the former four, while 19 of the 29 patients (66%) received greater than 6000 cGy. Acute complications during radiation were observed in 18 of the 29 patients (62%). In only one case, however, irradiation was interrupted because of acute complications. Late complications, observed six months or more after the end of irradiation and required admission to the hospital for diagnosis or treatment, were developed in four of the 29 patients (14%). They were contracted bladder, perforation of the rectum, bladder neck contracture and ileus. Patients with ileus and contracted bladder each had history of laparotomy and vesical stone, respectively. As to portals and total dose of these four, anterior-posterior parallel opposing portals only was conducted in all and total dose was less than 6000 cGy in three of them. The results of this study revealed the superiority of the combined therapy over hormone therapy alone for treating Stage C prostatic cancer, and also showed the optimum total dose and portals