CT virtual endoscopy of the stomach: comparison study with gastric fiberscopy.

BACKGROUND: We evaluated the value of computed tomographic (CT) gastric virtual endoscopy (VE) by comparing it with real gastric fiberscopy (GF). METHODS: Sixty-six VE findings in 63 patients were compared with lesions found with GF. After a GF examination, the examinees were given bubble-making granules for the stomach and placed in a supine position on the CT table. Abdominal CT slices of 1 mm thickness were obtained by multidetector row CT (Siemens Sensation 16) and reconstructed to VE images with volume and surface rendering on the same day. RESULTS: VE images were successful in showing subtle alterations in the gastric mucosal folds. Gastric cancer, polyps, ulcers, erosions, and gastritis were clearly visualized. Comparison studies between VE and GF (as the gold standard) showed a sensitivity of 92.7% and a specificity of 90.9%. Original CT images were also useful in detecting lesions in other abdominal organs such as the liver, adrenal gland, and kidney. CONCLUSION: Because VE is a good noninvasive screening method, except for minimal radiation exposure, it is expected to become a new technique for stomach examinations.

[Three-dimensional MR angiography of HCC and portal and hepatic veins using superparamagnetic iron oxide].

We examined a new MR technique for obtaining 3D-MRA images of the liver that simultaneously depicts HCC and the portal and hepatic veins. Five patients with clinically suspected HCC were studied with superparamagnetic iron oxide (SHU-555A) used as a negative contrast medium for the liver. In our study, a 3D-rotational display was provided on the CTR monitor from 2D-TOF images by computed reconstruction, clearly showing HCC and portal and hepatic veins on the same image. Our method was found to be of great value in planning surgery of the liver.

Acalculous cholecystitis (panniculitis) associated with Weber-Christian disease.

Acalculous cholecystitis occurred in a patient with Weber-Christian disease. It reflected a panniculitis similar to that which developed in the orbit, abdominal cavity, and the retroperitoneal space.

Dynamic MR studies of hepatocellular carcinoma with portal vein tumor thrombosis.

Gd-DTPA enhanced dynamic MR studies were evaluated in six patients with hepatocellular carcinoma associated with portal vein tumor thrombus. The portal vein tumor thrombus was clearly visualized as a low intensity lesion. The hepatic segment supplied by the portal vein showed high intensity, probably due to decreased portal blood flow and compensatory arterial blood flow. Tumors located in this segment were shown as areas of relatively low intensity compared with segmental high intensity areas. Thus dynamic MR study was found to be a useful method for differentiating the tumor from the surrounding nontumorous tissue with decreased portal blood flow.

Retroperitoneal schwannomas simulating adrenal tumors.

Tumors in the area of the adrenal were detected by chance in two patients who underwent a regular physical check-up. On arteriography the tumors were found to be fed by the adrenal artery. The diagnosis was retroperitoneal schwannoma, but in both patients it was difficult to differentiate the schwannoma from an adrenal tumor preoperatively.

[Regenerating nodules in liver cirrhosis--patho-MR-serological correlation study].

An MR study was performed in 73 clinically diagnosed cirrhotic patients to determine correlations among the demonstration of small low intensity nodules (SLINs), secondary changes due to cirrhosis, and serological data. In 32 patients, liver cirrhosis was proved histologically. SLINs were observed in 38 of the 73 patients on gradient echo (GRE) images and in 28 patients on T2-weighted SE images. Patho-MR correlation study of the liver in the 32 histologically proved cirrhotic patients revealed that SLINs were seen on GRE images only in patients with iron deposits in regenerating nodules (RNs). There was no significant correlation between secondary changes due to liver cirrhosis and the demonstration of SLINs. Serological data indicating liver cell injury and iron store in the body were significantly higher in patients with iron deposits in RNs than in those without iron deposits.

Differentiation between hepatoma and hemangioma with inversion-recovery snapshot FLASH MRI and Gd-DTPA.

Thirty-eight patients with focal liver tumors (20 hepatomas, 18 hemangiomas) were studied by dynamic sequential inversion recovery (IR) snapshot fast low angle shot (FLASH) MR imaging with Gd-DTPA. Immediately after 0.05 mmol/kg Gd-DTPA was administered intravenously for 2-3 s followed by flushing with normal saline for 4-5 s, 10 images were obtained in the first 20 s (time zero is the end of flush, early phase). Then, one image every 30 s from 1 to 3 min (late phase) and images at 5 min and 7 min (delayed phase) were obtained serially. Hepatomas showed total enhancement in 18 of 20 patients in the early phase, and isointense or low intensity enhancement with respect to the surrounding liver parenchyma in 18 patients in the late to delayed phases. Hemangiomas showed peripheral enhancement in 14 patients in the early phase, but did not show total enhancement (except for two hemangiomas less than 3 cm in size) in the early phase, and showed high intensity enhancement in 15 patients in the late phase. Ninety percent of hepatomas and 82% of hemangiomas showed their characteristic enhancement patterns in the early to delayed phases. We conclude that dynamic sequential IR snapshot FLASH MR images enhanced with Gd-DTPA can facilitate differentiation between hepatomas and hemangiomas.

Siderotic nodules in hepatic cirrhosis disappearing after biliary hemorrhage: MR imaging.

Magnetic resonance demonstrated siderotic regenerating nodules in a patient with hepatocellular carcinoma with accompanying liver cirrhosis. The siderosis disappeared when iron deficiency anemia developed in association with biliary hemorrhage. Magnetic resonance was sensitive enough to follow changes in the siderosis. The mechanism of iron deposition in regenerating nodules that accompanied liver cirrhosis did not seem to be related to the severity of the liver damage.

[Dynamic MRI of hepatocellular carcinoma with portal vein tumor thrombus].

Dynamic MRI with injection of Gd-DTPA was performed in 7 patients with hepatocellular carcinoma associated with portal vein tumor thrombus. A portal vein tumor thrombus was clearly visualized as a low intense structure. The segment supplied with this portal vein shows high intensity, probably due to the decrease in portal blood flow and compensated arterial blood flow. A tumor itself, located in this segment, was shown as a low intense area. Thus dynamic MRI is a useful method for differentiating the tumor from the surrounding nontumorous tissue with decrease in portal flow.

Limitation of transcatheter arterial chemoembolization using iodized oil for small hepatocellular carcinoma. A study in resected cases.

The radiologic and histologic findings are presented of the resection of 14 small hepatocellular carcinomas (HCC), less than 2 cm in maximum diameter, after transcatheter arterial chemoembolization (TCE) using iodized oil. The effect of TCE on small HCC depended on the morphologic type of the tumors. When no extracapsular invasion of tumor cells occurred, TCE was extremely effective against encapsulated tumors. However, in nine of the 14 resected specimens, viable tumor cells remained in or around the tumor. The authors suggest that small HCC are not always curable with TCE alone and that a multi-disciplinary approach is necessary for patients with small HCC.

Regenerating nodules in hepatic cirrhosis: MR findings with pathologic correlation.

To establish clearly the pathologic basis for small low-intensity nodules seen on MR images of the cirrhotic liver, we obtained MR images in 26 patients with cirrhosis in whom partial hepatectomy for hepatoma (15 patients), laparoscopy for cirrhosis (10 patients), or autopsy (one patient) was subsequently performed. Small low-intensity nodules were seen on gradient-echo images with short TEs (10-13 msec) in 13 of the 26 patients. In 12 of these 13 patients, small low-intensity nodules appeared larger and clearer as the TE was prolonged (14-25 msec). On T2-weighted spin-echo images, small low-intensity nodules were seen in 12 of the 13 patients, but not seen as well as on gradient-echo images. Pathologic correlation in these 13 patients revealed that the nodules on the MR images corresponded to iron deposits in regenerating nodules. Small low-intensity nodules were observed only on T2-weighted spin-echo images in two of the remaining 13 patients, in whom microscopic examination of the liver revealed marked inflammatory cell infiltration in the fibrous septa and no iron deposition. We conclude that small low-intensity nodules observed on MR images are caused by iron deposits in regenerating nodules, and that gradient-echo images with short and prolonged TEs are useful to confirm the presence of iron deposits in regenerating nodules.

[MRI of hepatocellular carcinoma--the intensity changes after TCE].

Magnetic resonance (MR) imaging of the liver has been useful in detecting hepatic tumors, especially hepatocellular carcinoma (HCC), and in characterizing the internal architecture of HCC. In this paper, we present MR image of the resected cases of HCC with the pathological findings, and assess MR image for the potential utility of demonstrating the pathologic features of HCC treated with TCE.

[Dynamic MRI of liver tumors--evaluation by inversion recovery snap shot FLASH MR imaging].

We have studied 20 patients with liver tumor (hepatoma 12, hemangioma 6, metastatic tumor 2) using inversion recovery snap shot FLASH dynamic MR imaging. After intravenous injection of Gd-DTPA, serial 17 images were obtained during 7 minutes. Hepatoma showed central enhancement on early phase (0-20 sec) in 11 patients and absent or less enhancement than surrounding liver parenchyma on late phase (1-3 min) in 12 patients. Hemangioma showed peripheral enhancement on early phase in 6 patients, and slight to moderate enhancement on late phase in 5 patients. Peripheral slight enhancement were seen on late and delayed (5-7 min) phase in two patients with metastatic liver tumor. These characteristic enhancement patterns should facilitate differential diagnosis of liver tumors.

Portal blood flow in congestive heart failure: pulsed duplex sonographic findings.

Twenty-one patients with congestive heart failure were examined with duplex sonographic scanning of the portal vein. The Doppler sonographic findings were compared with those of healthy subjects, patients with chronic liver disease, and patients with Budd-Chiari syndrome. Increasing pulsatility of the Doppler signals was demonstrated in 11 patients with severe congestive heart failure. Two patients with severe congestive heart failure showed decreasing pulsatility of portal Doppler signals in response to therapeutic procedures. Portal flow patterns suggestive of severe congestive heart failure include a monophasic forward flow with peak velocity in ventricular diastole and gradual diminution of velocity throughout ventricular systole (n = 5), a reversed flow velocity in ventricular systole (n = 3), and vena cava-like biphasic forward velocity peaks during each cardiac cycle (n = 2). The time-velocity waveform shape of portal flow is, to a large degree, influenced by the mechanical events in the right side of the heart in severe congestive heart failure.

Computed tomographic arteriography of the liver using balloon occlusion.

The article describes a new method for computed tomographic arteriography (CTA) of hepatocellular carcinoma (HCC) using a balloon occlusion catheter in 8 patients. Our dynamic study indicated that: 1) a bolus injection of contrast medium with our method of CTA (CTA-B) produced an attenuation difference between liver and tumor which was about double that obtained with standard methods for CTA, and 2) marked tumor-liver attenuation differences (above 20 HU) persisted for more than 60 s in CTA-B and for not more than 20 s with conventional methods for CTA. The results show that CTA-B is superior to standard methods in enabling multiple scans of the liver during greater and prolonged differential tumor enhancement after administration of a bolus of contrast medium. In conjunction with table incrementation, CTA-B allows scanning of the entire liver at the time of maximal contrast enhancement with two to three injections of contrast medium. Two patients complained of abdominal pain during balloon inflation. No other complications were observed.

Effect of transcatheter arterial embolization on the boundary architecture of hepatocellular carcinoma.

Daughter nodules and intrahepatic metastases are resistant to conventional transcatheter arterial embolization therapy. To clarify the mechanism of this resistance, the boundaries of hepatocellular carcinomas and their relationship to the blood supply were studied. The boundaries of the hepatocellular carcinomas studied were classified as one of five types: encapsulated, granulation, stromal, replacing, or sinusoidal. The granulation and stromal types had a capsule-like structure, but lacked the hyalinization which is the hallmark of a true tumor capsule. The granulation and stromal types could also be differentiated from the encapsulated type because of their different blood supplies and the differing effects of transcatheter arterial embolization. When barium sulfate was infused into the portal vein, it did not enter into encapsulated tumors, but it entered granulation and stromal type tumors. Small nodules such as daughter nodules and intrahepatic metastases do not have capsules, and so have a blood supply that makes them resistant to conventional transcatheter arterial embolization therapy.

[Siderotic regenerating nodules in liver cirrhosis--evaluation by gradient echo (FLASH) imaging 1.5T].

In three patients with histologically proven liver cirrhosis, a large number of small, low-intensity nodule(SLIN)s was clearly seen on gradient echo(GRE) images which are sensitive to field inhomogeneity. A histological study revealed that the SLINs corresponded to the regenerating nodules, laden with iron, of liver cirrhosis. As TE was prolonged, the SLINs increased in size in all three cases and fused with each other in one of three cases on GRE images. This phenomenon suggests that the magnetic susceptibility effect due to iron included in the regenerating nodules is the cause for the regenerating nodules shown as SLINs on GRE images, and that one SLIN does not always correspond to one regenerating nodule. We conclude that GRE images should be considered important for diagnosis of regenerating nodules in liver cirrhosis.