Postoperative low-dose follow-up computed tomography for patients with stomach cancer: optimal blending ratio of adaptive statistical iterative reconstruction for image quality and diagnostic performance.

OBJECTIVE: To compare the diagnostic performance of adaptive statistical iterative reconstruction applied low-dose computed tomography (CT) (LDCT) with that of the standard-dose CT (SDCT) for local recurrence in patients with stomach cancer. METHODS: Seventy-nine consecutive patients who had undergone surgical resection for stomach cancer were enrolled. To monitor recurrence, SDCT (120 kilovolt peak [kVp], 200mAs) had been performed. The LDCT (120 kVp, 100 mA s) was taken, and images were reconstructed with 4 levels of adaptive statistical iterative reconstruction (ASIR) blending (0%, 30%, 50%, and 70%). Two blinded radiologists recorded the diagnostic confidence scores for local recurrence in each data set using a 5-point scale. Endoscopic biopsy results served as the reference standard. Receiver operating characteristic (ROC) curve analysis was used to calculate the diagnostic performance. RESULTS: The diagnostic performance of LDCT with variable ASIR blending ratios was comparable to that of SDCT (area under ROC curve, 0.727-0.734, 0.687, respectively, P > 0.05). CONCLUSIONS: The diagnostic performance of ASIR applied LDCT is comparable to that of SDCT.

Quarter regular dose non-enhanced CT for urinary stone: added value of adaptive statistical iterative reconstruction.

BACKGROUND: As urinary stone diseases are common in young adults and have a high recurrence rate, repetitive computed tomography (CT) scans would increase the radiation hazard. Therefore, CT radiation dose reduction is needed in the diagnosis of urinary stones. PURPOSE: To prospectively evaluate the added value of adaptive statistical iterative reconstruction (ASIR) applied to half-dose (HDCT) and quarter regular dose non-enhanced CT (QDCT) for the detection of urinary stones. MATERIAL AND METHODS: One hundred and twelve consecutive patients who presented with acute flank pain and had clinically suspected urinary stones were initially eligible. All patients underwent non-enhanced CT that consisted of HDCT (120 kVp, 100 mAs) and QDCT (120 kVp, 40 mAs). The images were reconstructed separately with a 50% ASIR blending ratio. Two radiologists independently performed a 2-week interval reading to detect urinary stones on a per stone basis (size ≥1 mm) from the QDCT images to the ASIR applied images. Two weeks later, the HDCT images were analyzed in the same manner. The CT image noise was measured for each image set. The sensitivity for urinary stone detection for each set was compared using the McNemar test. RESULTS: A total of 114 urinary stones were found in 48 patients (37 men, 11 women; mean age, 46 years; range, 19-71 years). After applying ASIR to the QDCT images, the sensitivity increased from 70% to 80% for reader 1 and from 69% to 82% for reader 2 (P = 0.001, respectively). However, in the HDCT images, the sensitivity was unchanged for both readers (reader 1, 87%; reader 2, 89%). The measured noise significantly decreased from 40.2 to 27.7 after applying ASIR to the QDCT images and from 25.1 to 17.6 after applying ASIR to the HDCT images (P = 0.001 for both). CONCLUSION: Although ASIR showed no added diagnostic value for HDCT images, it improved the sensitivity for the detection of urinary stones based on QDCT images.

Apparent diffusion coefficient for discriminating metastatic from non-metastatic lymph nodes in primary rectal cancer.

OBJECTIVE: To investigate whether the apparent diffusion coefficient (ADC) could be used to discriminate metastatic from non-metastatic lymph nodes (LNs) in patients with primary rectal cancer. METHODS: This study investigated 34 patients (male: 12, female: 22, mean: 62.7, range: 37-82) who underwent 1.5-T MRI with diffusion-weighted imaging (DWI) and subsequent surgical resection. A blinded radiologist measured the ADC value in each regional LN after referring to the T2-weighted images and DWI. The t-test was used to compare the mean ADC values of the metastatic and non-metastatic LNs. A ROC analysis was performed to calculate the diagnostic performance and obtain the optimal cut-off. The histopathological results were used as the reference standard. RESULTS: 114 LNs (46 metastatic and 68 non-metastatic) were matched and analyzed. The mean ADC of the metastatic LNs was significantly lower than that of the non-metastatic LNs (0.9 ± 0.15 × 10(-3) mm(2)/s; 1.1 ± 0.22 × 10(-3) mm(2)/s, P<0.0001). The area under the ROC curve was 0.734 (95% confidence interval, 0.644-0.812). When an ADC value of 1.0 × 10(-3) mm(2)/s was used as the cut-off, a maximum accuracy of 72% was calculated (sensitivity, 78%; specificity, 67%). CONCLUSIONS: Although ADC could be used to discriminate metastatic from non-metastatic LNs, the diagnostic accuracy is approximately 70%.

Acetic acid sclerotherapy for treatment of a bile leak from an isolated bile duct after laparoscopic cholecystectomy.

Bile leak after laparoscopic cholecystectomy is not uncommon, and it mainly occurs from the cystic duct stump and can be easily treated by endoscopic techniques. However, treatment for leakage from an isolated bile duct can be troublesome. We report a successful case of acetic acid sclerotherapy for bile leak from an isolated bile duct after laparoscopic cholecystectomy.

Imaging findings of intravascular papillary endothelial hyperplasia presenting in extremities: correlation with pathological findings.

OBJECTIVE: To describe magnetic resonance imaging (MRI) and ultrasound (US) findings of intravascular papillary endothelial hyperplasia (IPEH) arising in extremities. MATERIALS AND METHODS: Six patients with IPEH confirmed by surgical resection were reviewed retrospectively. Before resection, 3 patients underwent both MRI and US and 3 patients underwent only MRI. Two radiologists retrospectively reviewed MR/US imaging results and correlated them with pathological features. RESULTS: The 6 IPEHs were diagnosed as 4 mixed forms and 2 pure forms. The pre-existing pathology of four mixed forms was intramuscular or intermuscular hemangioma. By MRI, the mixed form of IPEH (n = 4) revealed iso- to slightly high signal intensity containing nodule-like foci of high signal intensity on T1-weighted images (T1WI) and high signal intensity-containing nodule-like foci of low signal intensity on T2-weighted images (T2WI). The pure form of IPEH (n = 2) showed homogeneous iso- signal intensity on T1WI and high and low signal intensity containing nodule-like foci of low signal intensity on T2WI. On gadolinium-enhanced fat-suppressed T1WI, 50% of cases (n = 3: mixed forms) revealed peripheral, septal, and central enhancement. The other IPEHs (n = 3: 1 mixed and 2 pure forms) showed peripheral and septal enhancement or only peripheral enhancement. By US, two mixed forms of IPEH showed well-defined hypoechoic masses containing hyperechoic septa and central portion with vascularities. One pure form of IPEH was a homogeneous hypoechoic mass with septal and peripheral vascularities on color Doppler imaging. The foci of high signal intensity on T1WI, foci of low signal intensity on T2WI, and non-enhancing portions on MRI and the hypoechoic portion on US were histopathologically correlated with thrombi and the peripheral/septal or central enhancing areas on MRI, hyperechoic septa and the central portion on US, and septal/central or peripheral vascularities on color Doppler imaging corresponded to hypertrophic papillary epithelium and a fibrovascular core. CONCLUSIONS: Even though imaging findings of the pure form of IPEH are rather nonspecific, the mixed form of IPEH should be considered a possible diagnosis when a well-defined mass with T2 hyperintense signal containing nodule-like foci of low signal intensity, T1 iso- to slightly hyperintense signal containing nodule-like foci of high signal intensity, and peripheral/septal or central enhancement on MRI is seen in extremities, along with the US finding of a hypoechoic mass containing hyperechoic septa with vascularities.

Size and location of ruptured intracranial aneurysms.

OBJECTIVE: The aim of study was to review our patient population to determine whether there is a critical aneurysm size at which the incidence of rupture increases and whether there is a correlation between aneurysm size and location. METHODS: We reviewed charts and radiological findings (computed tomography (CT) scans, angiograms, CT angiography, magnetic resonance angiography) for all patients operated on for intracranial aneurysms in our hospital between September 2002 and May 2004. Of the 336 aneurysms that were reviewed, measurements were obtained from angiograms for 239 ruptured aneurysms by a neuroradiologist at the time of diagnosis in our hospital. RESULTS: There were 115 male and 221 female patients assessed in this study. The locations of aneurysms were the middle cerebral artery (MCA, 61), anterior communicating artery (ACoA, 66), posterior communicating artery (PCoA, 52), the top of the basilar artery (15), internal carotid artery (ICA) including the cavernous portion (13), anterior choroidal artery (AChA, 7), A1 segment of the anterior cerebral artery (3), A2 segment of the anterior cerebral artery (11), posterior inferior cerebellar artery (PICA, 8), superior cerebellar artery (SCA, 2), P2 segment of the posterior cerebral artery (1), and the vertebral artery (2). The mean diameter of aneurysms was 5.47+/-2.536 mm in anterior cerebral artery (ACA), 6.84+/-3.941 mm in ICA, 7.09+/-3.652 mm in MCA and 6.21+/-3.697 mm in vertebrobasilar artery. The ACA aneurysms were smaller than the MCA aneurysms. Aneurysms less than 6 mm in diameter included 37 (60.65%) in patients with aneurysms in the MCA, 43 (65.15%) in patients with aneurysms in the ACoA and 29 (55.76%) in patients with aneurysms in the PCoA. CONCLUSION: Ruptured aneurysms in the ACA were smaller than those in the MCA. The most prevalent aneurysm size was 3-6 mm in the MCA (55.73%), 3-6 mm in the ACoA (57.57%) and 4-6 mm in the PCoA (42.30%). The more prevalent size of the aneurysm to treat may differ in accordance with the location of the aneurysm.

Tetra-arsenic oxide (Tetras) enhances radiation sensitivity of solid tumors by anti-vascular effect.

Tetras (tetra-arsenic oxide, As(4)O(6)) is a derivative of arsenic used in Korean traditional medicine for the treatment of cancer, but its mechanism remains largely undefined. Recently, a similar arsenic derivative, diarsenic trioxide (As(2)O(3), ATO), has been shown to mediate anti-tumor activity, therefore reigniting interest in the therapeutic effect of arsenic compounds. Here we report that Tetras can effectively mediate an anti-vascular effect on tumors, leading to delay in tumor growth and increased survival. Our study demonstrates for the first time the potential use of Tetras as a radiation therapy enhancement agent for solid tumors. These findings reveal an unappreciated role of Tetras in cancer therapy and its potential application to radiotherapy in achieving local tumor control.

Usefulness of Diffusion-Weighted MRI for Differentiation between Parkinson's Disease and Parkinson Variant of Multiple System Atrophy.

BACKGROUND AND PURPOSE: Several studies have reported that diffusion-weighted imaging (DWI) is able to help discriminate a Parkinson variant of multiple system atrophy (MSA-p) from Parkinson's disease (PD) on the basis of the increased regional apparent diffusion coefficient (rADC). We analyzed the usefulness of DWI by using the rADC for differential diagnosis between MSA-p and PD and investigated the correlation between the rADC value and clinical features of MSA-p and PD. METHODS: Twelve patients with PD and 10 with MSA-p were studied. The rADC value was determined in different brain regions, including the dorsal putamen (DP) and middle cerebellar peduncles (MCP). RESULTS: The rADC values of the DP showed a greater increase in MSA-p patients than in PD patients (p=0.03). MSA-p patients also presented increased rADC values of the MCP compared with PD patients (p=0.0001). In particular, the sensitivity, specificity and positive predictive values of the MCP rADC were higher than those of the DP rADC. However, DP and MCP rADC values were not correlated with clinical features in either MSA or PD patients. CONCLUSIONS: DWI discriminated between PD and MSA-p based on rADC values in DP and MCP. The MCP rADC value, in particular, could better discriminate MSA-p from PD.

The steroid effect on the blood-ocular barrier change induced by triolein emulsion as seen on contrast-enhanced MR images.

OBJECTIVE: The purpose of this study is to evaluate the effect of dexamethasone on the damaged blood-ocular barrier caused by triolein emulsion, using contrast-enhanced MR imaging. MATERIALS AND METHODS: An emulsion of 0.1-mL triolein in 20 mL of saline was infused into the carotid arteries of 32 cats, 12 cats were placed in the treatment group and 18 cats were placed in the Control group. Thirty minutes after the infusion of triolein emulsion, a set of orbital pre- and post-contrast T1-weighted MR images (T1WIs) were obtained. Infusion of 10 mg/kg dexamethasone into the ipsilateral carotid artery of each of the cats in the treatment group cats and 20 mL saline in each of the cats in the control group was given. A second set of pre- and post-contrast orbital T1WIs were obtained three hours following triolein emulsion infusion. Qualitative analysis was performed for the the anterior chamber (AC), the posterior chamber (PC), and in the vitreous humor of the ipsilateral and contralateral eyes. The signal intensity ratios of the ipsilateral eye over the contralateral eye were quantitatively evaluated in the three ocular chambers on the first and second set of T1WIs, and were then statistically compared. RESULTS: Qualitatively, the AC, the PC or the vitreous did not show immediate contrast enhancement on the first and the second set of post-contrast T1WIs. However, the AC and the PC showed delayed contrast enhancement for both groups of cats on the second pre-contrast T1WIs. No enhancement or minimally delayed enhancement was seen for the vitreous humor. Quantitatively, the signal intensity ratios in the PC of the treatment group of cats were statistically lower than the ratios of the control group of cats for the second set of T1WIs (p = 0.037). The AC and vitreous showed no statistically significant difference between the feline treatment group and control group (p > 0.05). CONCLUSION: Contrast-enhanced MR images revealed increased vascular permeability in the PC of the eye after infusion of triolein emulsion. Dexamethasone seems to decrease the breakdown of the blood-aqueous barrier in the PC.

Intracortical lipoma of the femur.

Intracortical lipoma is an extremely rare benign primary bone tumor. We encountered a case of an intracortical lipoma found incidentally in the femur of a 31-year-old female. Magnetic resonance imaging and computed tomography of the femur demonstrated an intracortical fatty lesion in the posterolateral aspect of the diaphysis. The intracortical lesion showed some intramedullary extension, multiple septations, and dot-like calcifications. Intralesional curettage was performed. Histologically, the tumor consisted of mature, viable adipocytes without foci of fat necrosis or dystrophic calcification.

Ex vivo proton MR spectroscopy (1H-MRS) for evaluation of human gastric carcinoma.

The present study was performed to determine the characteristics of the biochemical metabolites related to gastric cancer using ex vivo (1)H magnetic resonance spectroscopy (MRS), and to assess the clinical usefulness. A total of 35 gastric specimens resected during surgery for gastric cancer were used to compare MR spectra. A 1.5-T (64-MHz) clinical MR imager equipped with facilities for spectroscopy was used to obtain MR spectra from 33 gastric specimens. High-resolution (1)H nuclear magnetic resonance (NMR) spectra of the remains of two specimens were also examined with a 9.4-T (400-MHz) NMR spectrometer. Localized spectroscopic measurements were performed in two layers of gastric tissue, the proper muscle layer and the composite mucosa/submucosa layer. T(2) FSE and 3D SPGR images were used to determine the voxel size and the location for MRS data collection. MR spectra were obtained using the single-voxel PRESS technique with parameters of TR/TE = 2000/30 ms, NA = 256, and voxel size = 3 x 3 x 3 mm(3) (27 microL). Cancerous and noncancerous gastric tissues in the voxel were determined by histopathological analysis. On 9.4-T ex vivo NMR spectroscopy, the following metabolite peaks were found: lipids at 0.9 ppm (CH(3)) and 1.3 ppm (CH(2)); alanine (beta-CH(3)) at 1.58 ppm; N-Acetyl neuraminic acid (NANA: sialic acid) at 2.03 ppm; and glutathione at 2.25 ppm in normal gastric tissue layers. In the 1.5-T MR system, broad and featureless spectral peaks of the various metabolites in normal human gastric tissue were observed at 0.9 ppm, 1.3 ppm, 2.0 ppm, and 2.2 ppm regardless of gastric tissue layer. In specimens (Borrmann type III) with tubular adenocarcinoma, resonance peaks were observed at 1.26 ppm, 1.36 ppm (doublet of lactate), and 3.22 ppm (choline). Cancer lesions showed decreased levels of lipid peaks, showing the significant lactate doublet peaks, and increased intensity of the choline peak as compared with noncancerous gastric tissue. We found that decreased levels of lipids and increases in lactate and choline peaks in gastric tissue were markers for malignancy in gastric lesions. Information provided by ex vivo (1)H MRS, together with the development of in vivo (1)H MRS with high field strength and high resolution, may be very useful for the diagnosis of gastric cancer in clinical situation.

Tetraarsenic oxide, a novel orally administrable angiogenesis inhibitor.

Arsenic compounds have been used to treat angiogenic diseases such as cancer, psoriasis, and rheumatoid arthritis in traditional oriental medicine. In recent years, arsenic trioxide (As2O3, diarsenic oxide) has been successfully used to treat acute promyelocytic leukemia. We investigated the antiangiogenic properties of tetraarsenic oxide (As4O6), another trivalent arsenic compound. In in vitro studies, tetraarsenic oxide inhibited the proliferation (IC50 = 99.7 nM), migration into the denuded area (IC50 = 27.4 nM), and invasion through a layer of Matrigel (IC50 = 73.5 nM) of basic fibroblast growth factor (bFGF)-stimulated bovine capillary endothelial (BCE) cells in a dose-dependent manner. Tetraarsenic oxide also inhibited the tube formation of human umbilical vein endothelial cells. Tetraarsenic oxide induced cell cycle arrest of bFGF-stimulated BCE cells in the G2/M phase and inhibited the secretion of matrix metalloproteinase-2 from BCE cells. Orally administered tetraarsenic oxide (50 mg/kg/day) inhibited bFGF-induced new-vessel formation in a rat corneal micropocket assay, and reduced by about 54% the number of experimental pulmonary metastatic nodules in mice implanted with B16F10 melanoma cells. Thus, we provide evidence that tetraarsenic oxide has effective antiangiogenic activities.