Steatohepatitic hepatocellular carcinoma: imaging findings with clinicopathological correlation.

AIM: To evaluate the clinicopathological and computed tomography (CT) and magnetic resonance imaging (MRI) findings of steatohepatitic hepatocellular carcinoma (SH-HCC). MATERIALS AND METHODS: Clinicopathological and radiological features were evaluated in 20 patients with SH-HCC. The diagnosis of SH-HCC was made histologically if the tumour had four of the following five characteristics: steatosis (>5% tumour cells), ballooning, Mallory-Denk bodies, interstitial fibrosis, and inflammation. All patients underwent dynamic CT and MRI. CT and MRI images were reviewed for morphological features including tumour size, presence, and distribution of fat, and patterns and degree of contrast enhancement. RESULTS: Obesity, hypertension, and history of heavy alcohol intake were common clinical findings observed in 10 (50%), 13 (65%), and 11 (55%) of the 20 patients, respectively. Steatosis and steatohepatitis were pronounced in the background liver in 12 (60%) and 10 (50%) patients, respectively. SH-HCC was moderately differentiated in 18 patients (90%) and well differentiated in two (10%). Pathologically, steatohepatitic features were diffuse in 12 (60%) of the 20 tumours and focal in eight (40%). Tumour size and the percentage of intratumoural steatosis were not correlated (r=0.17, p=0.47). On CT, 16 (80%) patients showed arterial phase enhancement and delayed washout. On MRI, 16 (80%) of 20 tumours showed prominent fatty deposition (10 diffusely, six focally) with arterial phase enhancement. CONCLUSIONS: SH-HCC is likely to show prominent fatty deposits with arterial phase enhancement on CT and MRI. A hypervascular lesion with prominent fatty change should raise the diagnostic suspicion of SH-HCC.

MR imaging of IgG4-related disease in the head and neck and brain.

SUMMARY: IgG4-related disease is characterized by histologic fibrosis with IgG4-positive plasma cell infiltration. Our study evaluated MR imaging features of IgG4-related disease in the head and neck and brain. Images from 15 patients were retrospectively evaluated for the location, signal intensity, and enhancement patterns of lesions. Lacrimal gland enlargement was observed in 8 cases. Other lesions included orbital pseudotumor in 5, pituitary enlargement in 5, and cranial nerve enlargement in 7; the infraorbital nerve was involved in 4. All lesions were hypointense on T2-weighted images, which is typical for IgG4-related lesions. Multiple sites were involved in the head and neck and brain in 11 patients. The diagnosis of IgG4-related disease should be considered in a patient presenting with T2 hypointense lacrimal gland, pituitary, or cranial nerve enlargement, or a T2 hypointense orbital mass, especially if multiple sites in the head and neck are involved in the presence of elevated serum IgG4.

Three-dimensional images of liver tumours reconstructed by Gd-EOB-DTPA-enhanced MRI.

The purpose of this study was to evaluate three-dimensional images of liver tumours obtained with gadolinium ethoxybenzyl diethylenetriamine penta-acetic acid (Gd-EOB-DTPA)-enhanced MRI (3D-EOB-MRI) in hepatic surgery. We conclude that 3D-EOB-MRI may be an alternative method for depicting liver tumours adjacent to the hepatic veins and portal branches, and may provide additional information for surgical planning.

Characteristics of intravascular large B-cell lymphoma on cerebral MR imaging.

IVL is characterized by a propensity for intravascular tumor cell proliferation. Premortem diagnosis of IVL is difficult because of its nonspecific clinical, laboratory, and imaging manifestations. This study examined cerebral MR imaging patterns of IVL and their changes with and without chemotherapy. Nine of 11 patients studied presented with abnormal findings. We define 5 patterns of abnormal MR imaging findings: 1) infarctlike lesions, 2) nonspecific white matter lesions, 3) meningeal enhancement, 4) masslike lesions, and 5) hyperintense lesions in the pons on T2WI. Seven patients presented with only 1 pattern, while 2 patients presented with multiple patterns. Lesions in 7 treated patients responded to chemotherapy. Pathologic specimens revealed intravascular tumor cell infiltration with associated infarctions, necrosis, congestion, demyelination, vasculitis, and tumor cell extravasation. We conclude that MR imaging patterns can be possible manifestations of intravascular-dominant infiltration by tumor cells with associated occlusion or inflammation, depending on the level of affected vessels.

Imaging of early pancreatic cancer on multidetector row helical computed tomography.

Early pancreatic cancer is small and limited to the pancreas. In contrast, small pancreatic cancer may include peripancreatic vasculature or metastasis involvement. This study evaluates images of early pancreatic cancer on multidetector CT (MDCT) using contrast-enhanced multiphasic imaging, and post-processed pancreatic duct images. CT findings and pathological features were analysed in eight patients with early pancreatic cancer. Pathological evaluation included location, size and histological grading of the tumour. MDCT evaluation covered the maximum diameter of the main pancreatic duct (MPD), stenosis or obstruction of the MPD, loss of normal lobar texture and associated pancreatitis. Attenuation differences between normal pancreatic parenchyma and the tumour (AD-PT) were also measured. Focal stenosis or obstruction of the MPD with dilatation of the distal MPD was demonstrated in all patients. Associated pancreatitis occurred in six patients with tumours measuring 12 mm or greater. Loss of normal lobar texture was recognised in four cases with the tumour measuring 14 mm or greater. Statistically, low-attenuated lesions and high-attenuated lesions differed with respect to the tumour size (p<0.01), and a positive relationship was demonstrated between the tumour size and AD-PT (r = 0.84). In seven cases, AD-PT is higher during the arterial phase than the pancreatic phase. Early pancreatic cancer appears as low attenuation on early phase, and as high- to iso-attenuation during the pancreatic and delayed phases in respect to the tumour size. Focal stenosis or obstruction of the MPD with dilatation of the distal MPD observed on curved reformation imaging seems important in the diagnosis of early pancreatic cancer.

Lens exposure during brain scans using multidetector row CT scanners: methods for estimation of lens dose.

BACKGROUND AND PURPOSE: Some recent studies on radiation lens injuries have indicated much lower dose thresholds than specified by the current radiation protection guidelines. The purpose of this research was to measure the lens dose during brain CT scans with multidetector row CT and to assess methods for estimating the lens dose. MATERIALS AND METHODS: With 8 types of multidetector row CT scanners, both axial and helical scans were obtained for the head part of a human-shaped phantom by using normal clinical settings with the orbitomeatal line as the baseline. We measured the doses on both eyelids by using an RPLGD during whole-brain scans including the orbit with the starting point at the level of the inferior orbital rim. To assess the effect of the starting points on the lens doses, we measured the lens doses by using 2 other starting points for scanning (the orbitomeatal line and the superior orbital rim). RESULTS: The CTDIvols and the lens doses during whole-brain CT including the orbit were 50.9-113.3 mGy and 42.6-103.5 mGy, respectively. The ratios of lens dose to CTDIvol were 80.6%-103.4%. The lens doses decreased as the starting points were set more superiorly. The lens doses during scans from the superior orbital rim were 11.8%-20.9% of the doses during the scans from the inferior orbital rim. CONCLUSIONS: CTDIvol can be used to estimate the lens dose during whole-brain CT when the orbit is included in the scanning range.

Patient skin dose during neuroembolization by multiple-point measurement using a radiosensitive indicator.

BACKGROUND AND PURPOSE: Although neuroembolization has recently spread quickly, sufficient attention has not been focused on the associated radiation exposure. The purpose of this research was to evaluate the patient's entrance skin dose (ESD) during neuroembolizations in 6 institutions. MATERIALS AND METHODS: This study was approved by all of the 6 institutional review boards, and all of the patients gave informed consent. This study included a total of 103 consecutive neuroembolizations in the 6 institutions. Patient ESDs during the procedures were evaluated by using caps that had 44 radiosensitive indicators adherent to the surface. The patient ESDs were calculated from the color difference of the indicators. To check for effects on the scalp, clinical follow-up was performed at 1-2 days, 2 weeks, and 3 months after the procedure. RESULTS: The averages of total fluoroscopic time, total number of digital subtraction angiography frames, and dose area product were 67.1 +/- 41.6 minutes, 883 +/- 626, and 257 +/- 150 Gy x cm(2), respectively. The average maximum ESD for each patient was 1.9 +/- 1.1 Gy (range, 0.4-5.6 Gy; median, 1.5 Gy). The average maximum ESDs of each institution ranged from 1.0 to 2.4 Gy. Epilation was observed in 6 patients. CONCLUSIONS: The maximum ESDs during neuroembolizations exceed the thresholds for radiation skin injuries in some cases.

New and reliable MRI diagnosis for progressive supranuclear palsy.

OBJECTIVE: To evaluate the area of the midbrain and pons on mid-sagittal MRI in patients with progressive supranuclear palsy (PSP), Parkinson disease (PD), and multiple-system atrophy of the Parkinson type (MSA-P), compare these appearances and values with those of normal control subjects, and establish diagnostic MRI criteria for the diagnosis of PSP. METHODS: The authors prospectively studied MRI of 21 patients with PSP, 23 patients with PD, 25 patients with MSA-P, and 31 age-matched normal control subjects. The areas of the midbrain tegmentum and the pons were measured on mid-sagittal MRI using the display tools of a workstation. The ratio of the area of the midbrain to the area of the pons was also evaluated in all subjects. RESULTS: The average midbrain area of the patients with PSP (56.0 mm2) was significantly smaller than that of the patients with PD (103.0 mm2) and MSA-P (97.2 mm2) and that of the age-matched control group (117.7 mm2). The values of the area of the midbrain showed no overlap between patients with PSP and patients with PD or normal control subjects. However, patients with MSA-P showed some overlap of the values of individual areas with values from patients with PSP. The ratio of the area of the midbrain to the area of pons in the patients with PSP (0.124) was significantly smaller than that in those with PD (0.208) and MSA-P (0.266) and in normal control subjects (0.237). Use of the ratio allowed differentiation between the PSP group and the MSA-P group. CONCLUSION: The area of the midbrain on mid-sagittal MRI can differentiate PSP from PD, MSA-P, and normal aging.

Unusual imaging appearances of pancreatic serous cystadenoma: correlation with surgery and pathologic analysis.

BACKGROUND: We describe imaging and pathologic features of serous cystadenoma of the pancreas on multislice helical computed tomography CT (MS-CT) and surgical resection. METHODS: Radiologic and pathologic features were analyzed in five patients. All patients underwent MS-CT and digital subtraction angiography (DSA), and four patients underwent magnetic resonance (MR) imaging. Preoperatively, three cases showed radiologic evidence of mainly solid appearance on MS-CT, and the suspected diagnoses were solid pancreatic tumors (patients 1-3). The other two cases showed radiologic evidence of macrocystic tumor of the pancreas, and the suspected diagnoses were mucinous cystic tumors (cases 4 and 5). All patients underwent surgery, and the diagnosis of serous cystadenoma was confirmed on pathologic examination. RESULTS: In three cases that showed a solid appearance on MS-CT, a microcystic appearance was identified on microscopic examination, and the tumors were found to be hypervascular lesions on multiphasic contrast-enhanced CT and DSA. In cases 1 and 2, the lesions showed high intensity with internal septation on T2-weighted MR images. In two cases, the tumors were classified as a macrocystic variant of serous cystadenoma, and no mural nodules, papillary projections, or calcifications were seen in the tumors. CONCLUSION: Imaging appearance of serous cystadenoma on MS-CT is various and sometimes indistinguishable from that of solid tumor or mucinous cystic tumors of the pancreas. Imaging findings of hypervascularity and a well-marginated high-intensity lesion with internal septation on T2-weighted MR imaging may be crucial to identify serous cystadenoma that contains no visible cystic compartments on MS-CT.

Isolated dissection of the superior mesenteric artery: CT findings in six cases.

Dissection of the superior mesenteric artery (SMA) not associated with aortic dissection is rare. The purpose of this study is to describe the computed tomographic (CT) findings of this condition. We studied the CT findings of six patients with isolated dissection of the SMA. CT demonstrated thrombosis of the false lumen or intramural hematoma (n = 4) and/or intimal flap (n = 4) in all six patients. Other CT findings were enlarged diameter of the SMA (n = 5), increased attenuation of the fat around the SMA (n = 5), and hematoma in the mesentery with hemorrhagic ascites (n = 1). CT is useful for the diagnosis of isolated dissection of the SMA, and increased attenuation of the fat around the artery is considered the key to the diagnosis when no definite findings are evident.

Quantitative flow visualization of fluidized-bed heat exchanger by neutron radiography.

Quantitative flow visualization of a gas-solid fluidized-bed installed vertical tube-bank has been successfully conducted using neutron radiography and image processing technique. The quantitative data of void fraction distribution as well as the fluctuation data are presented. The time-averaged void fraction is well correlated by the drift-flux model. The bubbles formed in the bed, rise along the vertical tubes and the observed bubble size is smaller than that in a free bubbling bed without tube-banks. The bubble diameter is well correlated by the modified Mori and Wen's correlation taking into account the pitch of tube arrangement. The bubble rise velocity is also well correlated by applying the drift-flux model. These results are consistent for both bed materials of Geldart's B- and A-particles, while the bubble size is significantly different between two kinds of particles.

Validation of CBF measurement with non-invasive microsphere method (NIMS) compared with autoradiography method (ARG).

The purpose of this study is to examine the correlation of measured regional cerebral blood flow (rCBF) by means of a new microsphere method (non-invasive microsphere method), to the autoradiography (ARG) method, which is an established quantification method for 123I-IMP brain SPECT. The non-invasive microsphere (NIMS) method and ARG method were simultaneously applied to 30 patients, and quantified rCBF maps were calculated with each method. A significant correlation (r = 0.70: p < 0.001) was detected between mCBF values calculated with the NIMS and ARG methods. This new method seems to reliably quantify rCBF with brain SPECT.

[A case of orbital MALT lymphoma in which 67Ga scintigraphy was useful for evaluating the radiation therapy response].

A 67-year-old man was hospitalized at our institution complaining with epiphora and exophthalmos on the left side. Magnetic resonance imaging (MRI) showed an ill demarcated retrobulbar mass in the left orbit. 67Ga scintigraphy revealed avid uptake in the left orbital region. The patient was treated with radiation therapy. One month after the radiation therapy, the size of the mass decreased remarkably on MRI. 67Ga planar imaging after treatment showed no uptake, but 67Ga SPECT showed slightly increased uptake in the left orbital region. One year after the radiation therapy, MRI showed residual mass in the left orbital region. Both 67Ga planar imaging and SPECT showed no uptake in the left orbital region. 1.8 years after the radiation therapy, MRI showed the residual mass with no interval change in size. Both 67Ga planar imaging and SPECT showed no uptake in the left orbital region. The patient remains well with no evidence of local recurrence. 67Ga scintigraphy is useful in assessing the response to radiation therapy of MALT lymphoma in this case.

Combination of preoperative embolization of the right portal vein and hepatic artery prior to major hepatectomy in high-risk patients: a preliminary report.

BACKGROUND/AIMS: Preoperative transhepatic portal vein embolization may not always be sufficient to achieve the desired changes in contralateral hepatic volume and function. The beneficial role of additional transcatheter arterial embolization performed after inadequate response to preoperative transhepatic portal vein embolization is described. METHODOLOGY: Four patients underwent both preoperative transhepatic portal vein embolization and transcatheter arterial embolization, and 6 control patients underwent preoperative transhepatic portal vein embolization only. Changes in right liver lobe volume fraction, residual left lobe volume fraction, and prediction score (low-risk, < 45; borderline, 45-55; high-risk > 55); were evaluated. RESULTS: 1) The change in right liver lobe volume after both preoperative transhepatic portal vein embolization and transcatheter arterial embolization (volume after/before) was 0.75 times that of the original level whereas after preoperative transhepatic portal vein embolization, they were only 0.81 times that of the original level. 2) The change in residual left liver volume after both preoperative transhepatic portal vein embolization and transcatheter arterial embolization (volume after/before) was 1.40 times that of the original level whereas after preoperative transhepatic portal vein embolization they were only 1.30 times than the original level. The changes in left liver volume after preoperative transhepatic portal vein embolization/transcatheter arterial embolization was more favorable than those after preoperative transhepatic portal vein embolization only. 3) The change in prediction score after both preoperative transhepatic portal vein embolization and transcatheter arterial embolization (after/before) was 0.81 times that of the original level. All prediction score in high-risk patients recovered to the borderline or safety zone. Change after preoperative transhepatic portal vein embolization only (before/after) was 0.87 times that of the original level. 4) All 4 patients who underwent both preoperative transhepatic portal vein embolization and transcatheter arterial embolization received right hepatic lobectomy successfully and returned to their normal life style. CONCLUSIONS: Preoperative occlusion of right hepatic inflow vessels increased the volume and function of the contralateral lobe where high-risk patients recovered to the borderline zone for major hepatic resection.

Multiple myeloma showing increased accumulation of Tc-99m hexamethylpropylene amine oxime on brain SPECT.

The authors report a case of multiple myeloma with increased accumulation of Tc-99m hexamethylpropylene amine oxime (HMPAO) on brain SPECT. Tc-99m HMPAO is a lipophilic compound that freely passes through the intact blood-brain barrier and cell membrane and is rapidly converted to a hydrophilic form by glutathione and then retained in the neuron for several hours. In general, Tc-99m HMPAO shows decreased accumulation in brain tumors. However, some reports of increased accumulation in brain tumors, such as meningioma, glioblastoma multiforme, high-grade astrocytoma, pituitary adenoma, and multiple myeloma, have been published. The Tc-99m HMPAO uptake in these tumors has been attributed to tumor blood flow or glutathione contents within the tumor. With regard to uptake to Tc-99m HMPAO in multiple myeloma, the tumor size is considered to be an additional factor.