Biomedical subjects
T Gokan
Publications and source records attributed to T Gokan.
Demonstration of aberrant hepatic and gastric arteries with helical CT.
RATIONALE AND OBJECTIVES: To assess the demonstration of aberrant hepatic and gastric arteries with routine axial biphasic helical CT. METHODS: The arterial-phase images of biphasic helical CT were reviewed to evaluate aberrant hepatic and gastric arteries in 166 patients with hepatocellular carcinomas. Biphasic (30 and 70 seconds) helical CT was performed with 10 mm of collimation. The results were compared with angiography performed within 2 weeks after this CT. RESULTS: Aberrant hepatic arteries were identified by CT in 38 patients and by angiography in 43 patients (38/43, 88%). Aberrant left gastric arteries were identified in three patients by angiography and by CT (3/3). Careful observation of the fissure for the ligamentum venosum and portacaval space was useful for the detection of these arteries. CONCLUSIONS: Aberrant hepatic and gastric arteries were well demonstrated with routine axial biphasic helical CT. This may be useful for the surgical and transcatheter management of hepatic tumors.
[Stage IIIa endometrial carcinoma: MR findings].
[PURPOSE]: An attempt was made to evaluate the ability of magnetic resonance (MR) imaging to diagnose stage IIIa endometrial carcinoma. [MATERIALS AND METHODS]: Thirty-three patients with endometrial carcinoma underwent MR imaging and surgery. Surgical staging was classified as I in 21 patients, II in 3 patients and III in 9 patients. The MR images of each patient were retrospectively reviewed by three radiologists. Only the clinical diagnosis of endometrial carcinoma was previously notified. Segmental disruption of the full thickness of the myometrium was considered serosal invasion. Intraperitoneal metastasis was diagnosed according to three criteria (intraperitoneal solid mass of isointensity compared with endometrial lesion, cystic mass excluding benign ovarian cysts, ascites). These evaluations were compared with the surgical findings and analyzed by the kappa statistic. [RESULTS]: The rates of sensitivity and positive predictive value (PPV) for serosal invasion were 33% and 6%, respectively. False positive evaluation frequently occurred when thickness of the intact myometrium was less than 5mm. The rates of sensitivity and PPV for intraperitoneal metastasis were 86% and 72%, respectively. The reason for false negative evaluation was small foci of intraperitoneal metastasis. Overall, sensitivity and PPV for stage IIIa were 86% and 69%, respectively. [CONCLUSION]: MRI was useful in detecting intraperitoneal metastasis of endometrial carcinoma with the exception of diagnosing serosal invasion. It is difficult to detect small foci of peritoneal metastasis. It is necessary to differentiate adnexal metastasis from benign adnexal masses.
Primary lymphoma of bone. Correlation of magnetic resonance imaging features with cytokine production by tumor cells.
BACKGROUND: Primary lymphoma of bone is a rare, aggressive neoplasm that can present with a large, soft-tissue mass despite minimal evidence of cortical destruction on plain radiographs. METHODS: High resolution magnetic resonance imaging (MRI) examinations of four patients with primary lymphoma of bone were reviewed retrospectively, and in each case intramedullary tumors demonstrated "penetrating channels" extending through the cortex. The MRI studies were correlated with the histopathologic assessment of the tumor for each patient. Immunohistochemistry was performed for immunophenotyping and for cytokine expression by tumor cells. The cytokines that were investigated were interleukin-1, interleukin-6, and tumor necrosis factor-alpha, molecules known to regulate osteoclastic activity. RESULTS: The linear cortical foci noted on MRI correlated with the histopathologic findings of tumor-associated cutting cones, in proximity to osteoclastic bone resorption. Immunohistochemical stains showed a B-cell phenotype for each tumor and positive immunoreactivity in tumor cells for cytokine mediators that stimulate osteoclastic activation. CONCLUSIONS: These findings indicate that the tumor cells in these cases produce soluble cytokine mediators that may regulate extensive osteoclastic activity. In primary lymphoma of bone, tumor activation of osteoclastic resorption, with production of tumor tunnels through the cortex, may represent one of the mechanisms by which lymphoma escapes the intramedullary space and forms large, soft-tissue masses without extensive cortical destruction.
[CT findings of primary retroperitoneal cystic tumors: special emphasis on the distinction benignancy from malignancy].
We describe the CT findings of primary retroperitoneal cystic tumors in 20 patients (cystic lymphangioma, 9; cystic teratoma, 3; cystic neurinoma, 4; mucinous cystadenocarcinoma, 3; synovial sarcoma, 1). CT findings were retrospectively reviewed and the findings correlated with the pathological findings to determine malignant or benign cystic tumors. Definite criteria for malignancy were invasion to surrounding organ and the presence of distant metastasis. However, the sensitivity of these criteria was very low (25%). Enhancement of an intracystic solid component was a reliable criterion (p < 0.05) for malignancy (sensitivity 75%, specificity 81%, accuracy 80%). Either unilocular cystic appearance or the presence of a "neck" (between the cystic mass and paraaortic region) strongly suggested the possibility of benignancy (specificity 100%). The "neck" was thought to be morphologically specific for cystic lymphangioma.
[US and CT findings of mucinous carcinomas of the gallbladder].
Mucinous carcinomas of the gallbladder are relatively uncommon. Their radiological findings have not been described previously. We describe the CT and US findings of mucinous carcinoma of the gallbladder in 3 cases. Tumors (thickened wall and/or intraluminal polypoid mass) showed hyperechogeneity or isoechogeneity on US and water density on CT. US clearly detected large polypoid lesions, but CT was unable to detect these lesions in 2 cases. Therefore, we stressed the discrepancy between the findings of US and CT. These features can be explained by the fact that a tumor containing a large amount of mucin produces a mass of near-water density in the gallbladder on CT. It is of value to know the radiological findings of these tumors because the diagnosis is easily missed by CT study alone.
[CT and MR imaging of desmoid tumors--comparison of two modalities].
As desmoid tumors invade locally and postoperative recurrence is common, accurate diagnosis of the extent of the tumor is needed prior to surgery. CT and/or MRI evaluation of tumor extension was retrospectively studied in eight patients with desmoid tumors, and the results were correlated with the histopathological findings. All tumors were completely resected even in patients who were evaluated by CT alone. However, the delineation of tumor and local invasion were not clearly demonstrated by CT. On the other hand, the delineation of tumor and local invasion were well visualized on MRI. The MRI picture of desmoid tumors was mainly composed of two different areas of signal intensity. The area of hypointensity in both T 1- and T 2-weighted images was found to have abundant collagen fibers, while the area of isointensity or slight hyperintensity in T 1-weighted images and hyperintensity in T 2-weighted images was found to have fibroblasts. In conclusion, MRI is better suited to the evaluation of patients with desmoid tumors than CT.
[CT findings of mucin-producing pancreatic cancer--differentiation from chronic pancreatitis].
Mucin-producing pancreatic cancers (MPPC), which include mucinous adenocarcinoma, papillary adenocarcinoma and cystadenocarcinoma, are radiographically characterized by diffuse or localized dilatation of the main pancreatic duct due to excessive mucin production. Therefore, MPPC are occasionally difficult to distinguish from chronic pancreatitis on CT unless the primary pancreatic lesion is visualized. We compared five cases of MPPC with five cases of chronic pancreatitis with marked duct dilatation to determine differences in CT images between the two diseases. There was no significant difference between the two diseases in the nature of duct dilatation (size, extent, contour) or parenchymal changes (atrophy, enlargement, calcification, cystic lesion). However, dilatation of the intramural duct was characteristically observed in MPPC but not in chronic pancreatitis. Papillary masses in the pancreatic duct, when observed, were another finding specific to MPPC.
[CT and US findings of gauzeoma].
We described the CT and US findings of gauzeoma in 7 patients, in which the masses were histologically proved. In the wide range of the CT findings, whirl-like spongiform pattern and the wavy striped high density area were characteristic of gauzeomas. The typical US features of gauzeomas were a cystic mass with the distinct internal echoes and strong acoustic shadows. The internal echo were occasionally curve-linear in shape. Gauzeomas are not common disease. However, when the findings described above are seen in the patients who have previously had an abdominal surgery, gauzeomas should be suspected.
A renal cell carcinoma extending into the renal pelvis simulating transitional cell carcinoma.
A case of renal cell carcinoma with unusual extension is reported, in which the radiographic findings have a close resemblance to those of transitional cell carcinoma of the renal pelvis. We emphasize that it is occasionally difficult to draw a distinction between transitional cell carcinoma with renal invasion and renal cell carcinoma with renal pelvic extension even by computed tomography (CT) and angiography.
Radiographic findings and hypotensive reactions in excretory urography.
The radiographic findings and the hypotension patterns were reviewed in 19 patients having hypotensive reactions in routine excretory urography using ionic contrast medium. The lowest systolic blood pressure was above 80 mmHg in 10 patients while below 80 mmHg in remaining 9 patients. The urogram was unremarkable as long as the systolic blood pressure was preserved above 80 mmHg. In 2 patients, whose systolic blood pressure decreased quickly beyond 80 mmHg immediately after injection of contrast medium, the pyelogram was faint or non-visualized. On the other hand, in 4 patients, whose systolic blood pressure decreased beyond 80 mmHg in several minutes after injection of contrast medium and remained under 80 mmHg for more than 20 minutes, the nephrogram was dense and the pyelogram was faint or non-visualized. Although systolic blood pressure decreased beyond 80 mmHg, the urogram was unremarkable in 3 patients. This was due to the delayed hypotension or the short duration of hypotension.
[Urinary tract involvement from pancreas carcinoma].
Pancreas carcinoma is sometimes notoriously difficult to diagnosis. It is well known that pancreas carcinoma can invade contiguous organs, but no attention for urinary tract involvement is paid. Urinary tract is involved at a late stage but may represent the first symptomatic evidence of disease. In such case, pancreas carcinoma can be presented initially as urologic disease and patients' symptom may not be differentiated from urinary tract disease. Computed tomographic (CT) images and medical records of 50 patients with histologically proved pancreas carcinoma were reviewed. There were 10 cases with urinary tract involvement. Those of 8 were male and 2 were female. There was a high incidence of left urinary tract involvement (left:right:bilateral = 7:2:1). Although 9 cases were pancreas body and tail carcinoma, 1 case was pancreas head carcinoma. And those stages were all in IV. All cases have confirmed evidence of urinary tract involvement at autopsy within 4 months following CT studies. IVP study was performed in 8 of these cases. We compared those IVP, CT images and findings of autopsy. In those patients, 4 cases showed direct invasion of the kidney, 5 cases showed ureteral involvement and 1 case showed metastasis to the urinary bladder and ureters. IVP showed inferior displacement of the kidney and/or ureteral displacement on the affected side. And also, collecting system distortion was demonstrated, including hydronephrosis secondary to ureteral compression. CT scan showed abnormal mass which is contiguous to the pancreas, showing compression the kidney and/or retroperitoneal extension with ureteral involvement. Metastasis to the urinary bladder is also identified. The findings of autopsy were almost the same of the CT findings. Pancreas carcinoma characteristically remains silent until little chance for cure. Although urinary tract involvement is rare, it can mimic renal and ureteral pathology. In differential diagnosis of urinary tract lesion, the disease process originated from pancreas should be included as well as from contiguous structures.
[A case report of leiomyosarcoma of the inferior vena cava].
A case of leiomyosarcoma of the I.V.C. is described, with emphasis on the CT appearance. CT is useful for the diagnosis and follow up on this case.
Radionuclide imaging for parotid oncocytoma.
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Radionuclide imaging of two patients with metastasis to a distal phalanx of the hand.
Although skeletal metastases from malignant neoplasms are common, the spread of cancer to the distal phalanx of the hand is quite rare. We have presented two cases with a distal phalangeal metastasis which could be definitely detected by radionuclide imaging.
[Increases of the perirectal and perivesical fat tissue in chronic urethral obstructive diseases; evaluations by CT scan].
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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.