Parasellar T2 dark sign on MR imaging in patients with lymphocytic hypophysitis.

BACKGROUND AND PURPOSE: MR imaging findings of LYH and pituitary adenomas are similar, but the therapeutic strategies are completely different. The purpose of this study was to evaluate sellar and parasellar MR imaging findings in patients with both diseases, as well as characteristic clinical findings. MATERIALS AND METHODS: Clinical findings, including endocrinologic study and MR images of 20 patients with LYH and 22 patients with pituitary adenoma, were retrospectively reviewed. We evaluated the MR images in relation to the following: 1) the PPHI on T1-weighted images, 2) thickened stalk (>3.5 mm), 3) pituitary symmetry, 4) pituitary enhancement pattern, 5) a dural tail, and 6) parasellar signal intensity on T2- and T1-weighted images. RESULTS: Between patients with LYH and those with pituitary adenoma, a significant difference was identified for the number of patients with loss of PPHI, thickened stalk, pituitary symmetry, homogeneous enhancement, and parasellar dark signal intensity on T2-weighted images by statistical analysis (Fisher exact probability test, P < .05). Among them, only parasellar dark signal intensity on T2-weighted images had no false-positive cases. CONCLUSIONS: The parasellar T2 dark sign can be a specific finding used to distinguish pituitary adenoma from LYH.

Commonly encountered adrenal pseudotumours on CT.

There are a variety of causes of adrenal pseudotumours on CT, including gastric diverticulum, prominent splenic lobulation, upper-pole renal mass, pancreatic mass, hepatic mass and periadrenal varices. These adrenal pseudotumours can be elucidated by multiplanar reconstruction using CT and MRI as well as from the axial images.

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.

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.

[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.

[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.

Small cell carcinoma of the prostate: CT and MRI findings.

We report two cases of small cell carcinoma of the prostate and describe the CT and MRI findings, which were primarily based on the rapid growth and high metastatic potential of the tumor. CT and MRI are extremely useful for demonstration of metastatic lesions. Histological confirmation is needed if the findings of CT or MRI are unusual for ordinary adenocarcinoma of the prostate.

[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.

[Radiation effect on anti-tumor activity of C3H mouse spleen cells to MH134 hepatoma cells].

Tumor-specific immunity was induced in C3H mice by immunizing with syngeneic MH134 hepatoma cells. The radiation sensitivity of tumor-specific effector cells in the immunized spleen cells and that of non-specific effector cells in normal spleen cells were compared. The spleen cells, both immunized and normal, were irradiated in vitro, then mixed with the tumor cells. The anti-tumor activity of the cells was measured by Winn assay and by a cytostatic test in vivo with diffusion chambers, on the basis of growth inhibition of tumor cells. The growth of tumor cells was inhibited by immune spleen cells more effectively than by normal spleen cells. The anti-tumor activity of immunized and normal spleen cells decreased dose-dependently in the respective ranges of 2.5-20 Gy and 2.5-10 Gy irradiation. In the normal spleen cells, anti-tumor activity was mainly detected in the fraction of non-adherent cells, not in adherent cells. The anti-tumor activity of non-adherent cells was diminished with 2.5 Gy irradiation. These results indicated that the radio-resistance of anti-tumor effector cells in C3H mice was increased by immunization with syngeneic MH134 hepatoma cells. Based on these and other findings in this experimental system, we concluded that tumor-specific effector cells that were radiosensitive at 10-20 Gy might involve delayed-type hypersensitivity (DTH) effector cells (macrophages) and that non-specific effector cells that were radiosensitive at 2.5-10 Gy might involve natural killer cells and lymphokine-activated killer cells.

[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 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.

[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.