Tamio Kushihashi

Helical CT demonstration of dilated right inferior phrenic arteries as extrahepatic collateral arteries of hepatocellular carcinomas

Purpose The purpose of this work was to demonstrate the appearance of the right inferior phrenic artery (RIPA) on CT in patients with hepatocellular carcinoma (HCC). Method We assessed the biphasic helical CT scans using 10 mm collimation in 16 patients with arteriographically proven HCCs supplied by the RIPAs. Size of the right and left inferior phrenic arteries and origin of the RIPA were evaluated and correlated with arteriographic images. Results Helical CT showed dilated RIPAs on the right diaphragmatic crus as foci of high attenuation on arterial-phase images in all patients. Diameter of the RIPA (average 3.3 mm) was larger than that of the left inferior phrenic artery (average 1.5 mm). The origin of the RIPAs was correctly predicted in 13 of 16 (celiac artery 6, abdominal aorta 5, right renal artery 2) patients. Conclusion Asymmetric dilatation of the RIPA as an indicator of extrahepatic collateral of HCC can be demonstrated on the right diaphragmatic crus with arteriographic images of biphasic helical CT.

CT Air-Contrast Enema as a Preoperative Examination for Colorectal Cancer

Background/Aims: We conducted a study on three-dimensional computed tomography (CT) images, in particular CT air-contrast enema (CT enema), using multidetector-row CT (MDCT), to see whether CT enema is useful as a preoperative examination for colorectal cancer. We aimed to evaluate the detectability of lesions and the depth of cancer invasion using CT enema. Methods: 292 patients (328 lesions) with colorectal cancer were enrolled. After an adequate insufflation of the large intestine, MDCT scans were performed. With the data obtained by MDCT, we reconstructed CT enema images. CT enema images were assessed for the detectability of lesions. The depth of invasion was evaluated by the deformity of the lesion on profile images. The deformities were divided into five groups: no deformity, slight deformity, mild deformity, moderate deformity and severe deformity. Results: The detectability of lesions was 97.3%. The reasons for undetectability were due to residual fluid in 8 cases and insufficient colonic distention in 1 case. As the depth of invasion increased, the grade of the deformity became severer (p < 0.0001). Conclusions: CT enema proved to be an excellent examination tool to detect lesions. The deformity demonstrated by CT enema could be an additional source of information to predict the depth of invasion.

Diffusion-weighted echo-planar MR imaging: clinical applications and pitfalls. A pictorial essay

Diffusion-weighted imaging (DWI) provides unique information about various pathological changes of the brain. DWI is sensitive for the detection of hyperacute infarcts, and useful in distinguishing acute or subacute infarcts from chronic infarcts. DWI is useful in differentiating cytotoxic edema from vasogenic or interstitial edema, which may help to determine prognosis. DWI is useful in differentiating cystic or necrotic tumors from abscesses or epidermoids. DWI can discriminate nonenhanced tumor infiltration from vasogenic edema, and differentiate dysmyelination from demyelination.

Computed tomography of retroperitoneal cystic lymphangiomas

The CT features of retroperitoneal lymphangiomas are unilocular or multilocular cysts in the retroperitoneum and slightly and uniformly thickened wall that enhances following contrast medium administration. Three cases are reported.

Polyethylene glycol solution (PEG) plus contrast medium vs PEG alone preparation for CT colonography and conventional colonoscopy in preoperative colorectal cancer staging

PurposeThis study evaluated the usefulness of combined polyethylene glycol solution plus contrast medium bowel preparation (PEG-C preparation) followed by dual-contrast computed tomography enema (DCCTE) and conventional colonoscopy. The main purpose of these examinations is the preoperative staging of already known tumors.Materials and methodsOne hundred patients with colorectal tumors were alternately allocated to either a polyethylene glycol solution preparation (PEG preparation) group (n=50) or a PEG-C preparation group (n=50) before undergoing conventional colonoscopy and computed tomographic (CT) colonography. After conventional colonoscopy, multidetector row CT scans were performed. Air images were reconstructed for both groups; contrast medium images were additionally reconstructed for the PEG-C preparation group. DCCTE images were a composite of air images and contrast medium images without use of dedicated electronic cleansing software. Quality scores (the presence or absence of blind spots of the colon) were compared between the two groups.ResultsComplete tumor images were obtained by DCCTE for all 50 (100%) lesions in the PEG-C preparation group, as compared with only nine of the 50 lesions (18%) in the PEG preparation group (air-contrast CT enema). The overall quality score in the PEG-C preparation group was significantly better than that in the PEG preparation group (P<0.0001).ConclusionsDCCTE showed the entire colon without blind spots in nearly all patients in the PEG-C preparation group because the areas under residual fluid were reconstructed as contrast medium images. DCCTE and conventional colonoscopy after PEG-C preparation are feasible and safe procedures that can be used for preoperative evaluation in patients with colorectal cancer.

Analysis of the anatomic changes in the thoracic cage after a lung resection using magnetic resonance imaging.

The thoracic cage after a lung resection is filled by the remaining lobes, the elevated diaphragm, the diminished thoracic cage, and by mediastinal shifting. The changes in the thorax after a lung resection were quantified using magnetic resonance imaging. The study group consisted of 39 patients who had undergone a lobectomy, four who had undergone a pneumonectomy, and 14 controls. The left ventricular angle, ascending aortic angle, mediastinal shift, longitudinal length of the thoracic cage, the distance between the thoracic apex and the level of the aortic valve, and diaphragmatic elevation were all measured. After a right lower lobectomy, the mediastinum shifted more rightward than after a right upper lobectomy. The diaphragm became more greatly elevated after a right upper lobectomy than after a right lower lobectomy. When a chest wall resection was added to a right upper lobectomy, the mediastinal anatomical changes decreased. After a left upper lobectomy, the degree of mediastinal shifting was greater than after a left lower lobectomy. A left upper lobectomy shifted the mediastinum at the level of the right atrium. This method is easily reproducible and was found to be effective for quantifying the changes in the thorax after a lung resection.

CT and MR findings in tuberculous mediastinitis.

Objective Tuberculous mediastinitis, a rare complication of pulmonary tuberculosis, may simulate a mediastinal tumor on chest radiography. For evaluation and follow-up of the disease, CT and MRI are needed. Materials and Methods Two cases of tuberculous mediastinitis are presented with emphasis on the importance of MRI. In both cases, MRI was performed because the CT appearance was unusual for a mediastinal tumor. Results The areas of low signal intensity within the anterior mediastinal mass on both T1− and T2-weighted imaging were due to the reactive fibrous tissue and were suggestive of an inflammatory mass. Conclusion When a mediastinal mass would be unusual on CT, MRI should be performed. If there are areas of low signal intensity within the mass on both T1− and T2-weighted imaging, an inflammatory mass such as tuberculous mediastinitis, is one of the possibilities.

Fast MRI in obstetric diagnoses.

This article describes the fast MRI of fetal abnormalities and placental anomalies in evaluation of the usefulness of fast MRI in obstetric diagnoses. Fast MRI provides excellent resolution for imaging fetal and maternal anatomies without the need for sedation. Fast MRI is therefore useful to clarify diagnoses suggested by equivocal ultrasonographic findings and to obtain additional information for prenatal counseling and management.

Skin Injuries Caused by Fluoroscopically Guided Interventional Procedures: Case-Based Review and Self-Assessment Module

OBJECTIVE Fluoroscopically guided interventional procedures are performed in cardiology, and complex interventions are performed in cerebral as well as peripheral circulation. These procedures sometimes deliver a high radiation dose to the patients skin and can cause serious skin injuries. CONCLUSION Interventionalists are often unaware of the high radiation doses to which a patients skin may be subjected. Most are unaware that such injuries can occur even with the use of modern equipment. Therefore, they and other physicians, including dermatologists, often do not recognize such skin injuries as being related to an interventional procedure.

CT demonstration of dilated gonadal vein as a portosystemic shunt of mesenteric varices.

Purpose The purpose of this work was to assess CT demonstration of the enlarged gonadal vein as a portosystemic shunt of mesenteric varices. Method The clinical records and CT images of eight patients with angiographically confirmed mesenteric varices were studied retrospectively. We measured the size of the right gonadal vein of these eight patients and also measured the size of the right gonadal vein in 60 patients without mesenteric varices. Results In all eight patients, CT demonstrated that the mesenteric varices drained into the inferior vena cava through the dilated right gonadal vein (diameter 6–10 mm) in all and that the left gonadal vein was not dilated (diameter 2–3 mm). In 60 patients without mesenteric varices, the diameter of the right gonadal vein was 1–5 mm. Conclusion CT demonstrates the dilated gonadal vein as a portosystemic shunt of the mesenteric varices. Awareness of a dilated gonadal vein in patients with portal hypertension may be helpful to consider the possibility of mesenteric varices.