Biomedical subjects

Y Hamashima

Publications and source records attributed to Y Hamashima.

At least 217 records · Page 12Linked to original sources

PubMedDate not supplied

Retroperitoneal liposarcoma: sonographic findings.

This study, based on sonographic (US) results of 10 cases with histologically proven retroperitoneal liposarcoma (eight well-differentiated and two pleomorphic types), shows that the presence of fine echogenic lines within the tumor is a useful sign for diagnosing a well-differentiated liposarcoma. Presence of numerous fine fibrous septa in the lipomatous tumor tissue is thought to be responsible for this interesting phenomenon. Of interest is the fact that the direction of these lines changed according to the probe format used: parallel horizontal lines when using a linear probe and concentric lines converging toward the probe when using a sector or curved linear probe. In contrast, pleomorphic liposarcoma does not show this US sign. Knowledge of these US findings is useful for the diagnosis of retroperitoneal liposarcoma.

Adult↗

PubMedDate not supplied

Macronodular hepatic deformity on normal liver.

BACKGROUND AND METHODS: Macronodular hepatic deformity on normal liver is very rare. We present nine such cases and try to define the characteristic clinical and ultrasound (US) findings. RESULTS: In the left lobe, the lateral segment was replaced by multiple nodules and the medial segment was very atrophied and irregularly shaped. Compared with the left lobe, the right lobe showed very few abnormalities except for segment 6, which showed a macronodular deformity. These nodules, regardless of diameter or lobe, showed a relatively homogeneous internal structure and were isoechoic relative to the surrounding hepatic parenchyma. These multinodular changes on US corresponded to multiple regenerative nodules identified at laparoscopic evaluation. On color Doppler US and angiography, the major intrahepatic vessels were patent in all cases. CONCLUSION: Although relatively rare, the macronodular hepatic deformity on normal liver collected in our series showed a characteristic appearance by US. A good understanding of its characteristics may help sonographers in differentiating it from other, more common hepatic deformities.

Adult↗

PubMedDate not supplied

Pancreatic metastasis: sonographic findings.

BACKGROUND: Pancreatic metastasis is a relatively rare pathologic condition. Its ultrasound (US) findings have been infrequently reported, and there has been no previous report describing its color Doppler findings. METHODS: We reviewed the US findings of 13 such cases. RESULTS: The pancreatic metastasis consisted of a single hypoechoic nodule in four cases and multiple hypoechoic nodules in nine cases. US showed a slight dilatation of the main pancreatic duct in two cases of pancreatitis, and a marked biliary dilatation in one case of jaundice. The US results prompted introduction of appropriate treatment in these cases. Color Doppler US was useful for confirming the absence of flow abnormalities in the arterial and portal systems around the pancreas. In a patients with renal carcinoma metastasis, it showed many fine blood flow signals in the metastatic lesions. CONCLUSION: The role of US in the diagnosis of pancreatic metastasis consists of associated complications such as biliary dilatation or pancreatitis and detection of isolated lesions. Additional information provided by color Doppler US may increase diagnostic confidence.

Adult↗

PubMedDate not supplied

Pancreatic uncinate carcinoma: sonographic findings.

BACKGROUND: Pancreatic carcinoma arising from the uncinate process (pancreatic uncinate carcinoma) is relatively rare. We wished to define its clinical manifestations and sonographic findings. METHODS: Clinical and sonographic data of eight cases were reviewed. RESULTS: The common bile duct and the pancreatic duct were not dilated until a very late stage. The lesion mimicked a mesenteric tumor in two cases. The superior mesenteric vessels were compressed anteriorly. Computed tomography was useful, not only for confirming the pancreatic uncinate origin of the lesion but also for determining precisely the mode of mesenteric vascular involvement. CONCLUSION: Knowledge of these unusual sonographic findings can determine the diagnostic strategy in pancreatic uncinate carcinoma.

Aged↗

PubMedDate not supplied

Macronodular deformity of the spleen.

BACKGROUND AND METHODS: Macronodular splenic deformity without a focal lesion has rarely been reported. We present three such cases and discuss the possible pathomechanism. RESULTS: There was one case of macronodular deformity of unknown cause. In this case, the liver was elongated anteriorly over the dome of the spleen, and the markedly deformed spleen mimicked a round lesion in the left lobe of the liver. Color Doppler ultrasonography showed the major intra- and perisplenic vessels to be patent. There were two cases of macronodular deformity associated with extended portal thrombosis. In both cases, portal thrombosis extended throughout the intrahepatic and extrahepatic portal systems, and this portal flow disturbance was presumed to be the cause of the splenic deformity. CONCLUSION: Although very rare, thrombosis should be sought throughout the portal system when ultrasonography shows a markedly deformed spleen. Marked splenic deformity, especially in cases with an elongated liver, may mimic a liver tumor. A good understanding of its sonographic appearance may help sonographers prevent a hazardous misdiagnosis.

Adult↗

PubMedDate not supplied

Duodenal carcinoma: sonographic findings.

BACKGROUND: Duodenal carcinoma is a relatively rare tumor and its sonographic (US) findings have rarely been reported. METHODS: We reviewed the clinical data and US results of 15 patients with histologically proven duodenal carcinoma to pinpoint the contribution of US to the diagnosis. RESULTS: US was useful for not only detecting the duodenal carcinoma (13 of 15, 86.7%), which altered the endoscopic procedure in nine patients, but also for evaluating vascular involvement (marked portal invasion in four cases and inferior vena cava invasion in two cases). Four of the eight carcinomas arising from the second or third portion showed this vascular invasion. CONCLUSION: After reviewing the clinical data and US results of 15 cases of duodenal carcinoma, we found that US was useful for detecting duodenal carcinoma and determining vascular invasion. Thus, US contributed significantly to alter the endoscopic procedure and patient management.

Carcinoma↗

PubMedDate not supplied

Peripheral bone metastasis from hepatocellular carcinoma: sonographic findings.

BACKGROUND AND METHODS: We reviewed medical and radiologic records of five patients with bone metastasis from hepatocellular carcinoma (HCC) to evaluate the role of sonography (US) in the diagnosis of this bone metastasis. RESULTS: The metastatic lesions were clearly visualized by US as expansive, homogeneous, soft tissue masses with bony destruction, and color Doppler US showed fine vessels within the lesions. After treatment, US showed a decrease in tumor size with an increase in echogenicity and a decrease in blood flow. Hepatic US at the time of bone metastasis showed a portal tumor thrombus in all cases. CONCLUSION: When US detects a portal venous tumor thrombus in HCC patients, attention should be directed not only to the liver but also to bone to improve patient care. US is useful not only in detecting the metastatic lesion but also in evaluating the treatment effect.

Bone Neoplasms↗

PubMedDate not supplied

Portal hypertension in children and young adults: sonographic and color Doppler findings.

Portal hypertension is a relatively uncommon pathologic condition in children and young adults in contrast with older adults. The aim of this study is to evaluate the utility of sonography and color Doppler sonography in the diagnosis of portal hypertension in children and young patients and to evaluate the sonographic pattern of each disease. We reviewed 25 such patients who were younger than 30 years old and obtained the following sonographic findings: (1) liver cirrhosis: (a) multiple intrahepatic venovenous shunts in patients with primary Budd-Chiari syndrome and (b) intrahepatic vascular narrowing and nodular coarse parenchymal texture, with multiple very-high-echo spots along the portal vein in patients with Wilson disease; (2) congenital hepatic fibrosis: marked and developed collaterals, wide periportal echogenic band, and a heterogeneous parenchymal texture comprised of multiple high echoes but without portal thrombus; and (3) extrahepatic portal thrombosis: invisible portal lumen except as an echogenic band. Sonography and color Doppler sonography are very useful in diagnosing these portal hypertensive diseases. However, there are no specific sonographic findings, and the role of sonography is limited to follow-up observation of associated secondary hepatobiliary changes in patients with congenital biliary atresia.

Adolescent↗

PubMedDate not supplied

Portal vein aneurysm: report of six cases and review of the literature.

Portal vein aneurysm is very rare, and its relation to portal hypertension has been emphasized. We report six cases of portal vein aneurysm (five extrahepatic and one intrahepatic). All patients were asymptomatic and had no signs suggestive of portal hypertension; the lesion was incidentally detected by ultrasound. Color Doppler sonography showed a constant hepatopetal flow along the aneurysmal wall, which immediately led to the diagnosis. We stress the usefulness of color Doppler sonography for studying the hemodynamics of this vascular anomaly and briefly review the literature.

Aneurysm↗

PubMedDate not supplied

Color Doppler findings of gastrointestinal varices.

BACKGROUND: Compared with esophageal varices, gastrointestinal varices are relatively rare, but they are clinically important because they tend to bleed massively. Color Doppler sonography is now widely used to diagnose the collaterals, but few color Doppler findings of gastric or intestinal varices have been reported. The aim of this study was to investigate the sonographic and color Doppler findings of gastrointestinal varices and to determine the role of color Doppler sonography in the diagnosis of these varices. METHODS: We studied 30 patients who were diagnosed by endoscopy as having gastrointestinal varices (24 gastric, four duodenal, two intestinal) with color Doppler sonography and compared the results with the clinical data. The causes of gastric varices included liver cirrhosis (16/24, 66.7%), idiopathic portal hypertension (3/24, 12. 5%), chronic pancreatitis with splenic vein thrombosis (2/24, 8.3%), congenital biliary atresia (1/24, 4.2%), congenital hepatic fibrosis (1/24, 4.2%), and unknown (1/24, 4.2%). The causes of duodenal varices included idiopathic portal hypertension with portal thrombosis (3/4, 75%) and liver cirrhosis (1/4, 25%). RESULTS: The gastric wall at the fundus was thickened in 17 of 24 cases (70.8%) with gastric varices, and the duodenal wall was thickened in four of four cases (100%) with duodenal varices. Sonography revealed thrombosis in the splenic vein in two of two cases with gastric varices secondary to chronic pancreatitis and in the confluence of the superior mesenteric vein and the splenic vein in three of four cases with duodenal varices. Color Doppler sonography demonstrated multiple, slow constant blood flows in the thickened wall in 15 of 24 cases (62.5%) with gastric varices and in four of four cases (100%) with duodenal varices. It demonstrated accumulated slow constant blood flows in the cecum in the case with cecal varices. Color Doppler showed also the communication between the varices and the neighboring vascular system (superior mesenteric vein and inferior vena cava) in the case with cecal varices, but it did not directly reveal such a communication in the other 29 cases (96.7%). Color Doppler showed a hepatofugal flow in the left gastric vein in all the hemorrhagic gastric varicose patients with esophageal varices, but it showed a hepatopetal flow in the left gastric vein in the isolated nonhemorrhagic gastric varicose patients. CONCLUSION: Color Doppler sonography was very useful for the diagnosis of gastric and duodenal varices and for visualizing fine venous flows in the thickened gastric or duodenal wall. When it shows portal thrombosis in the confluence of the splenic vein and the superior mesenteric vein, duodenal varices should be suspected. The flow direction of the left gastric vein helps to differentiate hemorrhagic gastric varices from nonhemorrhagic ones.

Adolescent↗

PubMedDate not supplied

Sonographic findings of anomalous position of the gallbladder.

Anomalous position of the gallbladder is relatively rare and has been reported only in isolated case reports. We tried to determine its ultrasound (US) findings on the basis of 18 such patients. In the left-side gallbladder group (nine patients), the gallbladder was imaged as an oval cystic mass in front of the pancreas. In all patients, the narrow neck of the gallbladder was clearly detected by US in the usual location before the main portal vein. Four of nine patients had small gallbladder stones. The retrohepatic gallbladder group (four patients) showed marked atrophy of the right lobe of the liver. Two patients had multiple gallstones in the bile ducts of the right lobe. All patients in the suprahepatic retrohepatic gallbladder group (four patients) were cirrhotic, and the anterior segment of the right lobe was markedly atrophied. In the intercostal scan, the gallbladder mimicked a perihepatic fluid. In the floating gallbladder group (one patient), the gallbladder was imaged as a cystic mass in the anterior abdominal wall. Surgical intervention showed a severely inflamed gallbladder, with small stones adhered into the anterior abdominal wall and partially ruptured. Knowledge of the wide range of US findings of malposition of the gallbladder helps in avoiding misdiagnosis.

Adult↗

PubMedDate not supplied

Lobar atrophy of the liver.

Lobar atrophy of the liver due to causes other than liver tumor or liver cirrhosis is a relatively rare pathological condition, and there are only a few reports in the literature. We report six such cases and try to evaluate the relationship between lobar atrophy and portal flow disturbance. The patients could be divided into two groups according to the site of the atrophy: those with atrophy of the left lobe (two cases) and those with atrophy of the right lobe (four cases). The two cases with atrophy of the right lobe had hepatholithiasis in the involved segments, but the cause was not determined in the remaining four cases. In all six cases, portal flow disturbance was noted, including invisibility of the portal vein in four cases, narrowing in one case, and portal thrombus in one case. Collateral circulation was not recognized in any of our cases. Of interest is the mode of lobar atrophy. Atrophy of the right lobe was always associated with marked enlargement of the left lobe, but that of the left lobe did not induce an enlargement of the right lobe.

Aged↗

PubMedDate not supplied

Intrahepatic venous collaterals.

BACKGROUND: The aim of this study was to reevaluate the causes and sites of intrahepatic venous collaterals and to determine the role of color Doppler sonography in the diagnosis of this relatively rare vascular abnormality. METHODS: Real-time color Doppler sonography was used to study 21 patients with intrahepatic venous collaterals. The cause, distribution, and clinical manifestations of collaterals were determined, and Doppler waveforms obtained from the collaterals were also analyzed. RESULTS: First, the causes of intrahepatic venous collaterals were divided roughly into two groups according to the presence or absence of veno-occlusions. The former group included liver tumors (six cases), primary Budd-Chiari syndrome (five cases), and metastatic adrenal tumors invading the inferior vena cava (two cases). The latter group consisted of diaphragmatic hernia (three cases), Osler-Weber-Rendu disease (two cases), and congestive liver (one case). The cause was not determined in two cases. Second, venous collaterals were distributed throughout the entire liver in primary Budd-Chiari syndrome but localized in the other cases. Third, Doppler waveforms of the collaterals were divided into two patterns: flat flow and multiphasic flow. Flat flow pattern was seen in patients with veno-occlusive diseases, and multiphasic flow pattern was seen in patients without veno-occlusive disease. CONCLUSION: The relationship between intrahepatic venous collaterals and veno-occlusive diseases has been emphasized in the literature, but the results of our series showed that they occurred under a wide variety of conditions, even without veno-occlusive diseases, including diaphragmatic hernia and Osler-Weber-Rendu disease. The analysis of the Doppler waveforms of the collaterals was useful in differentiating those due to veno-occlusive diseases and those not.

Adolescent↗

PubMedDate not supplied

Small bowel varices: report of two cases.

Two cases of small bowel (S-B) varices associated with portal hypertension, one with liver cirrhosis and one with portal thrombus, are reported. Detection of S-B varices has been a challenging task and several invasive diagnostic techniques have been used for this purpose. However, in our cases, color Doppler sonography revealed the S-B varices supplied by the superior mesenteric vein and draining to the iliac (one case) or ovarian vein (other case), which helped to establish an early appropriate diagnostic and treatment plan.

Aged↗

PubMedDate not supplied

Sonographic and color Doppler findings of gastrointestinal myogenic tumors with a marked extraluminal growth.

We present five cases with gastro (four cases) and intestinal (one case) myogenic tumors with a marked extraluminal growth. In all cases, incidental discovery of an asymptomatic mass prompted further examination. One of three cases with a pedunculated growth mimicked a gallbladder cancer. The mass of a jejunal leiomyoma case changed markedly in location under probe compression. Color Doppler sonography confirmed not only the hypervascular nature of the mass but also feeding and draining vessels.

Adult↗

PubMedDate not supplied

Sonographic and color Doppler findings of rupture of liver tumors.

We present six cases of ruptured liver tumor (hepatocellular carcinoma, five cases; liver metastasis, one case) in which gray-scale sonography revealed an ascites containing constantly moving dense high-echo spots, leading to a high suspicion of acutely developing hemoperitoneum. Color Doppler sonography helped in detecting the rupture site by demonstrating a high-velocity jet flow from it. Although four of six patients were dead within 3 months, detection of the rupture site by color Doppler sonography made the initial transarterial embolization therapy easy and prompt.

Adult↗

PubMedDate not supplied

Splenic artery aneurysm: value of color Doppler and the limitation of gray-scale ultrasonography.

BACKGROUND: To reevaluate the advantages and limitations of gray-scale and color Doppler sonography in the diagnosis of splenic artery (Sp-A) aneurysm. METHODS: We reviewed the gray-scale and color Doppler sonograms of five cases with Sp-A aneurysm (four patients with portal hypertension and one patient without portal hypertension). Color Doppler sonography was performed in all five patients, and power Doppler sonography was performed in three. RESULTS: Gray-scale sonography failed to detect the aneurysm in four of five cases because of a surrounding splenorenal (Sp-R) shunt in three patients and marked calcification of the aneurysmal wall in one patient. Pulsed Doppler sonography showed a slightly turbulent pulsatile flow along the aneurysmal wall, which immediately led to the diagnosis in four cases, including the three cases with Sp-R shunt. In one case, color Doppler sonography failed to detect the aneurysm because of a markedly calcified aneurysmal wall, although power Doppler sonography could visualize the aneurysm. CONCLUSIONS: Gray-scale sonography is not a useful diagnostic tool for Sp-A aneurysm. Clinicians should use color Doppler sonography in the evaluation of the splenic hilus in patients with Sp-R shunt to find a small Sp-A aneurysm. The addition of power Doppler sonography is helpful in visualizing calcified Sp-A aneurysms.

Adult↗

PubMedDate not supplied

Hepatic hemangioma with arterioportal shunts.

Color Doppler sonograms and angiographic findings in 23 hepatic hemangioma patients were compared to clarify how arterioportal shunts influence color Doppler findings of hepatic hemangiomas. The results of our study showed that the presence of arterioportal shunts (six cases) gave rise to large feeding arteries (five cases), multiple intratumoral flows (six cases), and reversal of portal flow within (five cases) or around (four cases) the tumor. These color Doppler findings mimicked hypervascular malignant tumors. Knowledge of such unusual color Doppler findings in hepatic hemangiomas may help in avoiding misinterpretations of color Doppler sonograms.

Female↗