Portal venous tumor thrombus associated with hepatic metastasis of renal cell carcinoma: case report.

We report a case of liver metastasis of renal cell carcinoma with portal venous tumor thrombus. Abdominal computed tomographic images showed a large hepatic mass that enhanced slightly during arterial phase. Multiple hypoattenuating lesions were seen in the intrahepatic portal venous branches and were traced directly from the mass. The histologic specimen confirmed metastatic liver tumor of renal cell carcinoma with portal venous tumor thrombus.

[Advanced gastric cancer: the findings of delayed phase dynamic CT and radiologic-histopathologic correlation].

PURPOSE: The aim of this study was to describe delayed phase dynamic CT findings of advanced (T2-T4) gastric cancer and to correlate with histopathologic findings. METHOD/MATERIALS: Quadruple phase dynamic CT including delayed imaging taken five minutes after the start of injection of contrast material was performed in 43 patients with 45 advanced gastric cancer and 20 control subjects with no gastric lesions. On delayed phase CT scans, the attenuation of the gastric wall was equal to or lower than that of the liver parenchyma in the control subjects, therefore, the presence of higher attenuation in the gastric wall was considered to be abnormal and defined as delayed enhancement. Histopathologic findings in the tumors showing delayed enhancement were compared with those in the tumors without this feature. RESULTS: Delayed enhancement was seen in 26 (57%) of the 45 tumors. Eleven of 25 differentiated-type tumors and 15 of 20 undifferentiated-type tumors showed delayed enhancement (P < .05). Delayed enhancement was seen in one of five medullary type tumors, in 11 of 25 intermediate-type tumors, and in 14 of 15 scirrhous-type tumors (P < .005). CONCLUSIONS: Delayed enhancement was frequently seen in the tumors with abundant fibrous tissue stroma. Delayed phase dynamic CT may be useful for the characterization of advanced gastric cancer.

Curvilinear areas in the perinephric fat seen on MR images.

AIM: On magnetic resonance (MR) images, strands correspond to curvilinear areas running in the perinephric fat, and haloes to those lying on the renal surface. Our aim was to examine the diagnostic significance and histopathological basis of these areas. PATIENTS AND METHODS: MR images obtained in 46 patients without renal disease and 96 patients with renal disease were assessed for the signal intensity and extent of strands and haloes, and their degree of right-left asymmetry. RESULTS: Strands usually revealed low signal intensity on T1-weighted MR images and high signal intensity on fat-suppressed T2-weighted images and contrast-enhanced fat-suppressed T1-weighted images. Haloes revealed high signal intensity on fat-suppressed T2-weighted images, but most of haloes were not clearly depicted on T1-weighted images or contrast-enhanced fat-suppressed T1-weighted images. Strands and haloes were common and usually symmetrical or only mildly asymmetrical in both patient groups. However, in 11 of the 96 patients with renal disease, prominent strands and/or haloes appeared with remarkable asymmetry and likely represented definite changes in the perinephric fat. At histopathology, vascular loose fibrous tissue was found at the sites of strands and haloes. CONCLUSION: Strands and haloes usually represent normal anatomical variations. However, the presence of prominent strands or haloes with remarkable right-left asymmetry implies abnormality and may provide additional information in the evaluation of renal disease.

Well-differentiated hepatocellular carcinoma: findings of US, CT, and MR imaging.

BACKGROUND: To elucidate the imaging characteristics of well-differentiated hepatocellular carcinomas (HCCs) on ultrasonography (US), computed tomography (CT), and magnetic resonance (MR) imaging. METHODS: Ultrasonograms, CTs, and MR images of 18 histopathologically proven well-differentiated HCCs in 15 patients were reviewed. The findings of these images were correlated with histopathologic findings. RESULTS: On US, seven tumors were depicted as a hyperechoic area and eight as a hypoechoic area. Three tumors were not visualized. On precontrast CT, four tumors were depicted as a low-density area, but 14 were not visualized. On conventional contrast-enhanced CT, 12 tumors were depicted as a low-density area but six were not visualized. On T1-weighted MR images, 10 tumors had high signal intensity and two had low signal intensity. Six tumors were not visualized. On T2-weighted MR images, five tumors had high signal intensity and two had low signal intensity. Eleven tumors were not visualized. Tumors with fatty change and/or clear cell formation were frequently hyperechoic on US and hyperintense on T1-weighted MR images. CONCLUSIONS: Well-differentiated HCCs show different findings on US, CT, and MR imaging. Therefore, reliable diagnosis of well-differentiated HCCs by these imaging techniques may be difficult.

[Pituitary enlargement in spontaneous intracranial hypotension on MRI].

PURPOSE: To examine whether the pituitary gland enlarges in patients with spontaneous intracranial hypotension (SIH). MATERIALS AND METHODS: All six patients were women ranging in age from 17 to 51 years. They developed severe headache that was completely relieved by lying flat, and MR imaging showed diffuse enhancement of the pachymeninx. They were clinically diagnosed with SIH. The height of the pituitary gland was measured on midsagittal MR image. RESULTS: Pituitary heights ranged from 8 to 11 mm. The measurements were greater than the size of the normal pituitary gland in women described age-matched in the previous report. In one case, follow-up MR images showed that the size of the pituitary gland was decreased from 11 to 5 mm in height. CONCLUSION: The pituitary gland was enlarged in all six patients with SIH on MR images. SIH may cause enlarged pituitary gland.

Decreased signal intensity of cerebral cortex on T2-weighted MR images.

To define the frequency of decreased signal intensity (DSI) in cerebral cortex on T2-weighted images relative to aging and to the incidence of identifying white matter pathology, T2-weighted MR brain images of 906 patients consecutively examined between July 1989 and June 1991 were reviewed. MR images of cerebral cortex were divided into five areas: frontal lobe (F), pre- and postcentral gyri (C), parietal lobe (P), occipital lobe (O) and temporal lobe (T). Each area was separately and independently evaluated for the presence or absence of DSI. The frequency of DSI in each area was plotted against patients' ages. The severity of leukoaraiosis was evaluated in relation with DSI in each cortical area. Patients with DSI in area F numbered 61 (5.7%), in area C 236 (26.0%), in area P 174 (15.9%), in area O 428 (47.2%), and in area T 10 (1.1%). The number of patients with DSI in each area increased with age. The greater the severity of leukoaraiosis, the greater the chance of finding DSI of the cerebral cortex. The incidence of DSI in the cerebral cortex increased with the patient's age as well as with the severity of co-existent white matter pathology.

[Evaluation of malignancy and viability of brain tumors by 201Tl SPECT: the correlation between 201Tl SPECT and pathology, clinical progress and the intensity of enhancement on CT images].

Thallium-201 (201Tl) SPECT was performed 48 times in 26 patients to clarify its usefulness in the evaluation of malignancy and viability of brain tumors. The early counts ratio (ER) and delayed counts ratio (DR) of a lesion compared with normal brain were obtained 10-15 minutes and 3 hours, respectively, after intravenous administration of 185 MBq of 201Tl chloride. Untreated high grade malignant tumors and recurrent tumors did not always show high ER and DR, and they were widely distributed. High grade malignant tumors that showed low ER and DR were not well enhanced on CT or MRI. In low grade malignant tumors, such as pituitary adenoma which was well enhanced on CT, ER and DR were as high as in high grade malignant tumor. Whether a tumor recurred within three months after radiotherapy or not was retrospectively predicted at accuracy rates of 93.8% and 87.5% with cut-off points of 4.0 for ER and 3.5 for DR. Cerebral radiation necrosis showed ring-like increased uptake of 201Tl in proportion to the progress of necrosis and intensity of enhancement on MRI. In conclusion 201Tl SPECT is considered to be less useful for lesions that are well enhanced on CT, because they show high uptake of 201Tl regardless of their malignancy and viability. On the other hand, in tumors that are not well enhanced on CT. 201Tl shows good accumulation in viable and high grade malignant lesions. 201Tl SPECT should be performed in such cases.

Adrenal adenomas: characteristic hyperintense rim sign on fat-saturated spin-echo MR images.

PURPOSE: To determine whether adrenal adenomas can be differentiated from metastases on fat-saturated magnetic resonance (MR) images. MATERIALS AND METHODS: Twenty-eight adrenal adenomas and 20 metastatic lesions were imaged at 1.5 T by means of fat-saturated T1- and T2-weighted and gadolinium-enhanced T1-weighted sequences. The authors evaluated visually whether structures of high signal intensity (hyperintense rim sign) could be observed in the outer margin of the adrenal masses. RESULTS: Twenty-six of 28 adrenal adenomas revealed the hyperintense rim sign on at least one kind of fat-saturated image, compared with only one of 20 metastases. The sensitivity of the hyperintense rim sign as suggestive of adrenal adenoma was 92%, specificity was 95%, and overall accuracy was 94%. CONCLUSION: The hyperintense rim sign is characteristic of adrenal adenomas. Thus, adrenal adenomas can be differentiated from metastases by means of this new imaging sign on fat-saturated MR images.

Septa in the liver of patients with chronic hepatic schistosomiasis japonica: MR appearance.

OBJECTIVE: Chronic hepatic schistosomiasis japonica is a disorder characterized by broad fibrous septa in the liver. The ability to recognize these septa on MR images might enable distinction of this lesion from other cirrhotic disorders. The purpose of this study was to analyze the MR appearance of these septa. MATERIALS AND METHODS: MR images of 18 patients who had typical calcifications of hepatic septa on CT scans were reviewed. The diagnosis was proved by biopsy in six patients. In the remaining 12, stool examinations were positive for schistosomiasis. T1-weighted MR images and T2-weighted and intermediate (long repetition time and short echo time) MR images acquired with the use of gradient-moment nulling were obtained in all 18 patients. In eight of 18 patients, additional T2-weighted and intermediate images were obtained without gradient-moment nulling. Fifteen patients had contrast-enhanced T1-weighted images. The presence of abnormal MR signal and its intensity at sites corresponding to the septa seen on CT scans were studied. RESULTS: MR images showed the septa as linear abnormalities frequently seen in the subdiaphragmatic portion of the right lobe of the liver. On T1-weighted images, septa had low signal intensity and were identified in nine of 18 patients. On T2-weighted images obtained with gradient-moment nulling, septa had high signal intensity and were seen in 13 of 18 patients. On T2-weighted images obtained without gradient-moment nulling, the septa had primarily low signal intensity and were seen in five of eight patients. On intermediate MR images obtained with gradient-moment nulling, the septa had primarily high signal intensity and were seen in nine of 18 patients. On intermediate images obtained without gradient-moment nulling, the septa had primarily low signal intensity and were seen in four of eight patients. In nine of 15 patients, septa were visualized as high-signal-intensity lesions on contrast-enhanced T1-weighted images. In 14 of 18 patients, the septa were detected in one or more sequences. CONCLUSION: Our experience suggests that MR imaging in patients with chronic schistosomiasis of the liver depicts the morphologic features of hepatic septa. MR signal characteristics of septa are not unique, but use of gradient-moment nulling alters the signal intensity of septa, similar to that of blood vessels, on intermediate and T2-weighted images.

Amyotrophic lateral sclerosis: T2 shortening in motor cortex at MR imaging.

PURPOSE: To determine whether decreased signal intensity of the motor cortex (T2 shortening) at magnetic resonance (MR) imaging is a useful finding for supporting the diagnosis of amyotrophic lateral sclerosis (ALS). MATERIALS AND METHODS: High-field-strength (1.5-T) MR images of 15 patients (seven men and eight women, aged 28-80 years) and 49 neurologically normal age-matched control patients were examined for T2 shortening in the motor cortex. In addition, brains of patients with ALS were examined at autopsy. RESULTS: The MR images of 14 of the 15 patients showed T2 shortening in precentral cortices, while the images of all but one of the control patients showed no such finding. In three of eight brains at autopsy, sections from the precentral cortex showed sparsely distributed, intensely stained astrocytes and macrophages. CONCLUSION: Abnormal iron deposition associated with the degenerative process could be the source of T2 shortening, which is a useful MR imaging finding in the diagnosis of ALS.

Schistosomiasis japonica of the liver: contrast-enhanced CT findings in 113 patients.

OBJECTIVE: The purpose of this study was to determine the findings on contrast-enhanced CT scans in patients with hepatic schistosomiasis japonica and to determine their pathologic basis. MATERIALS AND METHODS: Unenhanced and contrast-enhanced CT scans of 113 patients with histologically proved schistosomiasis were reviewed. Radiologic and pathologic findings were correlated after autopsy in 19 patients. RESULTS: Unenhanced CT scans showed septal calcification in the liver parenchyma in 53 patients (47%) and capsular calcification along the hepatic surface in 29 patients (26%). Twenty-seven patients (24%) had both types of calcification. Fifty-four patients (48%) showed one or more types of enhancement. Septal enhancement (i.e., linear enhancement of hepatic parenchyma looking like septa in the liver) was seen in 52 patients (46%). Forty-seven of the 53 patients who had septal calcification on unenhanced CT scans had septal enhancement on scans obtained after the administration of contrast material. The enhancement was found at sites of septal calcification in 44 patients and at noncalcified sites in 18 (15 had enhancement at both calcified and noncalcified sites). Five of 60 patients who did not have septal calcification on unenhanced CT scans had septal enhancement at noncalcified sites on scans obtained after the administration of contrast material. Amorphous enhancement (i.e., poorly defined and irregularly shaped enhancement) was seen in six patients (5%). Capsular enhancement (i.e., curvilinear enhancement along the hepatic surface) was seen in 12 patients (11%). Histologic studies showed broad fibrous septa at sites of septal enhancement. CONCLUSION: CT findings in patients with schistosomiasis japonica involving the liver include septal, amorphous, and capsular contrast enhancement. Septal enhancement occurs in broad fibrous septa. CT evidence of septal enhancement may suggest the diagnosis of hepatic schistosomiasis japonica, especially when no calcification is seen on unenhanced CT scans.

[Radiation stenosis and fistula formation developed after iridium-192 high-dose-rate intracavitary radiation boost therapy for carcinoma of the esophagus].

Intracavitary irradiation using a high-dose-rate Ir-192 remote after-loading system was applied to 14 advanced or inoperable patients with esophageal carcinoma as a boost therapy. The total dose of external irradiation was 45-70 Gy/15-35 fractions and that of intracavitary irradiation was 11.6-34.0 Gy/2-4 fractions at a point 5 mm deep from the inner surface of the esophageal mucosa. The time-dose-fractionation factor (TDF) of the whole treatment was 116-186 (mean, 146). Six patients (43%) had complete response (CR), three (21%) had partial response and five (36%) had no response. Esophageal carcinoma that showed exophytic growth, was less than 5 cm ling, and showed favorable response to external irradiation was likely to be a good candidate for intracavitary radiation boost therapy. Fistula formation was produced in five patients (36%), four of whom were irradiated at more than 140 TDF. All six CR patients were free from esophageal tumors, but severe esophageal stenosis due to radiation injury developed in five (83%) of them. They were irradiated at more than 135 TDF. One- and two-year survival rates were 28.6% and 14.3%, respectively. The poor prognosis was ascribed to the frequent occurrence of fatal radiation stenosis and fistula formation. An appropriate therapeutic dose for esophageal carcinoma that does not cause severe radiation stenosis was estimated to be under 120 TDF.

Dense parenchymal accumulation of Lipiodol after transarterial chemoembolization.

Dense accumulation of Lipiodol in hepatic segmental parenchyma was studied by computed tomography (CT) after transarterial chemoembolization (TACE) for hepatic tumor. Six patients showed dense accumulation of Lipiodol in hepatic segmental parenchyma on CT two weeks after TACE. Four of the six showed parenchymal accumulation of Lipiodol as dense as that in a tumor at three weeks after TACE. Therefore, it was considered that evaluation with CT should be performed after one month or more in order to differentiate between Lipiodol accumulation in tumors and that in non-neoplastic liver parenchyma.

[MR imaging of amyotrophic lateral sclerosis].

Magnetic resonance imaging (MR imaging) provides a sensitive method for mapping the normal and pathological distribution of iron in the brain. High field strength MR imaging (1.5 T) was used to evaluate eight patients with amyotrophic lateral sclerosis (ALS) and 49 neurological normal control patients. All eight ALS patients showed decreased signal intensity in the motor cortex on T2-weighted images, while only one of the normal control patients showed this finding. The results suggested that the decreased signal intensity in the motor cortex in ALS was caused by the deposition of iron in this area.

MR imaging of malignant mesenchymal tumors of the liver.

Magnetic resonance (MR) features of five primary malignant mesenchymal neoplasms (plasmocytoma, leiomyosarcoma, undifferentiated sarcoma, epithelioid hemangioendothelioma, and angiosarcoma) of the liver were reported. All tumors were hypointense on T1-weighted images and hyperintense on T2-weighted images. No halo and intravenous extension were noted. A target appearance was revealed in epithelioid hemangioendothelioma. MR findings of angiosarcoma were essentially the same as those of cavernous hemangiomas (markedly hyperintense with hypointense linear septa on T2-weighted images). MR findings of these rare hepatic malignancies were nonspecific, although they were quite different from those of typical hepatocellular carcinomas. This study suggested that MR differentiation of primary hepatic mesenchymal tumors from other common benign and malignant neoplasms was difficult; however, the number of studied cases was limited.

Membranous lipodystrophy: MR imaging appearance of the brain.

Five patients with membranous lipodystrophy (lipomembranous polycystic osteodysplasia with progressive dementia) underwent magnetic resonance (MR) imaging of the brain. T2-weighted MR images showed atrophied cerebral white matter with dilated ventricles; increased signal intensity of the white matter; and decreased signal intensity of the thalamus, putamen, caudate nucleus, and cerebral cortex. Although each single finding is not specific, the combination of the above MR findings when coupled with skeletal lesions strongly suggests this rare disease.

Magnetic resonance imaging of macroscopic intrahepatic portal-hepatic venous shunts.

Direct communication between portal branches and the hepatic vein [macroscopic intra-hepatic portal-hepatic venous shunt (IPHVS)] is a rare entity. We have recently studied five patients with this condition. Magnetic resonance imaging (MRI) clearly demonstrated in each case the portal-hepatic venous shunt due to "flow void." Multiple diffuse shunts were present in one case and a solitary shunt was demonstrated in the others. The solitary shunt was either tubular, focally dilated or racemose in configuration. The MRI findings and clinical significance of this rare entity are discussed.

Visualization of the bone/bone marrow of lower extremities in Ga-67 whole-body images.

Patients whose Ga-67 whole-body images showed increased uptake by the bone/bone marrow of the lower extremities were selected and classified into three types according to the extent and the grade of the visualization. These types were then compared with their serum iron levels, iron-binding capacities, and the results of several other serum biochemical tests. Of 374 consecutive whole body 72-hr images reviewed, 59 (15.8%) showed increased uptake of the tracer by the bone/bone marrow of the lower extremities. The three classified types were as follows: type T--visualization of both tibiae and femurs; type S--strong visualization of the femurs; and type W--weak visualization of the femurs. The serum iron concentration was significantly high in type T and low in type S. In conclusion, the pattern of Ga-67 uptake by the bone/bone marrow of the lower extremities fairly closely reflects the status of iron metabolism.

[Fundamental evaluation of bone densitometry using dual energy X-ray absorptiometry (DEXA)].

A newly developed instrument based on dual energy X-ray absorptiometry (DEXA), Hologic QDR-1000, was evaluated fundamentally and clinically. Image quality was quite satisfactory though radiation exposure was minimal, 780.2 nC/kg (3.024 mR) for lumbar measurement. Reproducibility of the repeated measurement of a phantom was fairly good; 0.343 CV% in a same day and 0.520 CV% in a long period. Accuracy determined by measurement of potassium phosphate solution was also satisfactory. Bone mineral densities measured by this instrument were fairly correlated with those measured by single energy quantitative CT; coefficient was 0.740 for 17 patients. Mix-DP plates of more than 10 cm thick overestimated the bone mineral densities of a phantom. Bone mineral densities of Japanese normal volunteers were in the normal range (mean +/- 2SD) of the Americans though mostly lower than the mean. In patients with spondylosis deformans or prominent aortic calcification, bone mineral densities might be overestimated. Lateral view was obtainable though its reproducibility was not good. Positioning especially for measuring femoral neck was quite critical for reproducible measurement. In conclusion, this new instrument is quite accurate and satisfactory for clinical application to measuring bone mineral densities.