Pseudoglandular Formation in Hepatocellular Carcinoma Determines Apparent Diffusion Coefficient in Diffusion-Weighted MRI

PURPOSE: To determine the impact of pseudoglandular formation on apparent diffusion coefficient (ADC) values of hepatocellular carcinoma (HCC) in diffusion-weighted imaging (DWI), and to validate the results using histopathological grades. MATERIALS AND METHODS: We assessed 182 HCCs surgically resected from 169 consecutive patients. Each type of tumor pseudoglandular formation was categorized into “non-,” “mixed-,” or “pure-,” based on official histopathology reports. The ADC for each tumor was independently measured, using the largest region of interest on the ADC map. Data were assessed using the analysis of variance test, with Bonferroni correction for post hoc analysis to stratify the relationship of ADCs with pseudoglandular formation, followed by subgroup analysis according to the histopathological tumor grades. RESULTS: The mean ADC was significantly higher in pure pseudoglandular lesions (n = 5, 1.29 ± 0.08 × 10−3 mm2/s) than in non-pseudoglandular lesions (n = 132, 1.08 ± 0.17 × 10−3 mm2/s; P = 0.003) or mixed-pseudoglandular lesions (n = 45, 1.16 ± 0.24 × 10−3 mm2/s; P = 0.034). The ADC values and pseudoglandular formation were significantly correlated in moderately differentiated HCCs (n = 103; r = 0.307, P = 0.007), while well- (n = 19) and poorly-differentiated HCCs (n = 60) did not show significant correlation (r = 0.105 and 0.068, respectively; P = 0.600 and 0.685, respectively). CONCLUSION: The degree of pseudoglandular formation could be one of the determinants of ADC in DWI of HCCs-especially moderately differentiated HCCs-while its influence does not appear to be significant in well- or poorly differentiated HCCs.

Attenuation-Based Automatic Tube Potential Selection in Cerebral Computed Tomography Angiography: Effects on Radiation Exposure and Image Quality

OBJECTIVE@#To investigate the feasibility of using the attenuation-based automatic tube potential selection (ATPS) algorithm for cerebral computed tomography angiography (CTA) and to assess radiation dose, vascular attenuation, and image quality compared to a conventional fixed 120-kVp protocol.@*MATERIALS AND METHODS@#Among 36 volunteers for cerebral CTA, a total of 18 were scanned with fixed 120 kVp and 140 effective mAs using automatic tube current modulation. The other 18 were scanned with an ATPS algorithm. Radiation doses, attenuation, contrast-to-noise ratio (CNR) of the cerebral arteries, subjective scores for arterial attenuation, edge sharpness of the artery, visibility of small arteries, venous contamination, image noise, and overall image quality were compared between the groups.@*RESULTS@#The volume CT dose index and effective dose of the ATPS group were lower than those of the fixed 120-kVp group. The ATPS group had significantly higher arterial attenuation and no significant difference in CNR, compared with the fixed 120-kVp. The ATPS group had higher subjective scores for arterial attenuation, edge sharpness of the artery, visibility of small arteries, and overall image quality.@*CONCLUSION@#The ATPS algorithm for the cerebral CTA reduced radiation dose by 43% while maintaining image quality and improved the attenuation of cerebral arteries by selecting lower tube potential.

Diffusion-Weighted MRI of Malignant versus Benign Portal Vein Thrombosis

OBJECTIVE: To validate the diffusion-weighted MRI (DWI) for differentiation of benign from malignant portal vein thrombosis. MATERIALS AND METHODS: The Institutional Review Board approved this retrospective study and waived informed consent. A total of 59 consecutive patients (52 men and 7 women, aged 40-85 years) with grossly defined portal vein thrombus (PVT) on hepatic MRI were retrospectively analyzed. Among them, liver cirrhosis was found in 45 patients, and hepatocellular carcinoma in 47 patients. DWI was performed using b values of 50 and 800 sec/mm2 at 1.5-T unit. A thrombus was considered malignant if it enhanced on dynamic CT or MRI; otherwise, it was considered bland. There were 18 bland thrombi and 49 malignant thrombi in 59 patients, including 8 patients with simultaneous benign and malignant PVT. Mean apparent diffusion coefficients (ADCs) of benign and malignant PVTs were compared by using Mann-Whitney U test. Diagnostic accuracy was evaluated using receiver operating characteristic (ROC) curve analysis. RESULTS: The mean ADC ± standard deviation of bland and malignant PVT were 1.00 ± 0.39 × 10(-3) mm2/sec and 0.92 ± 0.25 × 10(-3) mm2/sec, respectively; without significant difference (p = 0.799). The area under ROC curve for ADC was 0.520. An ADC value of > 1.35 × 10(-3) mm2/sec predicted bland PVT with a specificity of 94.6% (95% confidence interval [CI]: 84.9-98.9%) and a sensitivity of 22.2% (95% CI: 6.4-47.6%), respectively. CONCLUSION: Due to the wide range and considerable overlap of the ADCs, DWI cannot differentiate the benign from malignant thrombi efficiently.

Radiation Doses of Various CT Protocols: a Multicenter Longitudinal Observation Study

Emerging concerns regarding the hazard from medical radiation including CT examinations has been suggested. The purpose of this study was to observe the longitudinal changes of CT radiation doses of various CT protocols and to estimate the long-term efforts of supervising radiologists to reduce medical radiation. Radiation dose data from 11 representative CT protocols were collected from 12 hospitals. Attending radiologists had collected CT radiation dose data in two time points, 2007 and 2010. They collected the volume CT dose index (CTDIvol) of each phase, number of phases, dose length product (DLP) of each phase, and types of scanned CT machines. From the collected data, total DLP and effective dose (ED) were calculated. CTDIvol, total DLP, and ED of 2007 and 2010 were compared according to CT protocols, CT machine type, and hospital. During the three years, CTDIvol had significantly decreased, except for dynamic CT of the liver. Total DLP and ED were significantly decreased in all 11 protocols. The decrement was more evident in newer CT scanners. However, there was substantial variability of changes of ED during the three years according to hospitals. Although there was variability according to protocols, machines, and hospital, CT radiation doses were decreased during the 3 years. This study showed the effects of decreased CT radiation dose by efforts of radiologists and medical society.

Prognostic value of gallbladder wall thickening in patients with acute hepatitis A

PURPOSE: To investigate the clinical significance of gallbladder (GB) wall thickening frequently observed in patients with acute hepatitis A. METHODS: A total of 328 consecutive patients who were diagnosed with acute hepatitis A and underwent abdominal ultrasonography were enrolled retrospectively. Patients were divided into two groups: GB wall thickening (> or =3 mm, group A) and no thickening (group B). Group A was subdivided into two subgroups (GB wall thickening of > or =10 mm, group A-1 and > or =3 mm to <10 mm, group A-2). The laboratory results related to liver function, hospitalization duration, and time to normalization of liver function were compared between the groups. RESULTS: A total of 230 patients showed GB wall thickening (group A). Besides gamma-glutamyl transpeptidase and alkaline phosphatase, all laboratory results of group A were significantly higher than those of group B (P<0.05). Compared with group B, the hospitalization duration and the time to normalization of liver function were significantly longer in group A (P<0.05). Group A-1 included 146 patients and group A-2 included 84 patients. No significant differences in laboratory results, hospitalization duration, and time to normalization of liver function were found between the two subgroups. In the multivariate logistic regression analysis, serum alanine transaminase, total bilirubin and albumin levels, and hospitalization duration were significantly associated with GB wall thickening in patients with hepatitis A. CONCLUSION: The presence of GB wall thickening in patients with acute hepatitis A suggests a poorer prognosis irrespective of the degree of GB wall thickening or the degree of liver enzyme elevation.

Preoperative Evaluation of Lower Rectal Cancer by Pelvic MR with and without Gel Filling

PURPOSE: To assess the usefulness of rectal filling using ultrasonographic gel in patients with lower rectal cancer. MATERIALS AND METHODS: Twenty five patients with lower rectal cancer were enrolled. High resolution pelvic MR was performed twice before and after gel filling. Independently and retrospectively, two radiologists reviewed each set of MR images using five-grade scales for sphincter involvement, CRM (circumferential resection margin) involvement and depiction of the tumor. Same two radiologists retrospectively performed consensus review of each set of MR images for tumor distance from the anal verge and T&N staging. RESULTS: Tumor depiction scores from MR with gel filling were significantly higher than those of MR without distention (p0.05). Distance from the anal verge was significantly different between MR with gel filling and rigid endoscopy (6.8 +/- 1.6 cm vs. 5.8 +/- 1.6 cm, p=0.001). There were no significant differences between pathological staging and MR staging with or without gel filling. CONCLUSION: MR with gel filling improved tumor depiction. And also MR with gel filling revealed same ability for the predictions of CRM or sphincter invasion in patients with lower rectal cancer, comparing with MR without gel filling.

CT Venography for Deep Vein Thrombosis Using a Low Tube Voltage (100 kVp) Setting Could Increase Venous Enhancement and Reduce the Amount of Administered Iodine

OBJECTIVE: To investigate the validity of the 100 kVp setting in CT venography (CTV) in the diagnosis of deep vein thrombosis (DVT), and to evaluate the feasibility of reducing the amount of administered iodine in this setting. MATERIALS AND METHODS: After receiving the contrast medium (CM) of 2.0 mL/kg, 88 patients underwent CTV of the pelvis and lower extremities by using one of four protocols: Group A, 120 kVp setting and 370 mgI/mL CM; group B, 120 kVp and 300 mgI/mL; group C, 100 kVp and 370 mgI/mL; group D, 100 kVp and 300 mgI/mL. The groups were evaluated for venous attenuation, vein-to-muscle contrast-to-noise ratio (CNRVEIN), DVT-to-vein contrast-to-noise ratio (CNRDVT), and subjective degree of venous enhancement and image quality. RESULTS: Venous attenuation and CNRVEIN were significantly higher in group C (144.3 Hounsfield unit [HU] and 11.9), but there was no significant difference between group A (118.0 HU and 8.2) and D (122.4 HU and 7.9). The attenuation value of DVT was not significantly different among the four groups, and group C had a higher absolute CNRDVT than the other groups. The overall diagnostic image quality and venous enhancement were significantly higher in group C, but there was no difference between groups A and D. CONCLUSION: The 100 kVp setting in CTV substantially help improve venous enhancement and CNRVEIN. Furthermore, it enables to reduce the amount of administered iodine while maintaining venous attenuation, as compared with the 120 kVp setting.

Hepatic Cavernous Hemangiomas: Relationship between Speed of Intratumoral Enhancement during Dynamic MRI and Apparent Diffusion Coefficient on Diffusion-Weighted Imaging

OBJECTIVE: To investigate the relationships between the apparent diffusion coefficients (ADCs) on diffusion-weighted imaging (DWI) and the speed of contrast-enhancement in hepatic hemangiomas. MATERIALS AND METHODS: Sixty-nine hepatic hemangiomas (> or = 1 cm) were evaluated with DWI, by using multiple b values (b = 50, 400, 800 s/mm2), followed by a gadolinium-enhanced dynamic MRI. The lesions were classified into three groups, according to the speed of contrast-enhancement on the portal phase. ADCs were measured on the ADC map automatically, and were calculated by using the two different b values (mADC50-400 with b values = 50 and 400; mADC400-800 with b values = 400 and 800 s/mm2). RESULTS: The mean ADCs (x 10-3 mm2/s) were significantly higher in the rapid group (1.9 +/- 0.44) than in the intermediate (1.7 +/- 0.35, p = 0.046) or the slow groups (1.4 +/- 0.34, p = 0.002). There were significant differences between the rapid and the slow groups in mADC50-400 (2.12 vs. 1.48; p = 0.008) and mADC400-800 (1.68 vs. 1.22, p = 0.010), and between the rapid and the intermediate groups in mADC50-400 (2.12 vs. 1.79, p = 0.049). Comparing mADC50-400 with mADC400-800, there was a significant difference only in the rapid group (p = 0.001). CONCLUSION: Higher ADCs of rapidly-enhancing hemangiomas may be related to richer intralesional vascular perfusion. Also, the restricted diffusion may be attributed to the difference of structural characteristics of hemangioma.

Diffusion-Weighted MR Imaging before and after Contrast Enhancement with Superparamagnetic Iron Oxide for Assessment of Hepatic Metastasis

PURPOSE: The purpose of our study was to validate diffusion-weighted MRI (DWI) before and after superparamagnetic iron oxide (SPIO) injection for assessment of hepatic metastases. MATERIALS AND METHODS: Eighty-six hepatic metastases (size range, 0.3-4.7 cm; mean, 1.5 cm) verified pathologically or by follow-up imaging studies in 22 consecutive patients (17 men and 5 women; 44-83 years; mean age, 60 years) during a 13-month period were enrolled. Hepatic MRI, including DWI (b-factors=50, 400, 800 s/mm2) with breath-holding technique of single-shot spin-echo echo-planar imaging (TR/TE=1000/69 ms, average=2) before and after SPIO administration, were retrospectively reviewed by two independent radiologists with a 5-point scale confidence score for each hepatic lesion on pre-contrast DWI (pre-DWI), SPIO-enhanced DWI (SPIO-DWI), and SPIO-enhanced T2*-weighted imaging (SPIO-T2*wI). RESULTS: For all lesions, SPIO-T2*wI showed significantly higher confidence score in the diagnosis of hepatic metastases than pre-contrast or SPIO-DWI regardless of the size of b-factors (p0.05). Pre-DWI using b-factor=50 sec/mm2 was also comparable with SPIO-T2*wI by observer 1 (p=0.060). CONCLUSION: Pre-DWI has a limited value for the assessment of hepatic metastases, however, the repetition of DWI after SPIO injection using small b-factors could complement SPIO-T2*wI, especially for subcentimeter lesions.

Diagnosing Small Hepatic Cysts on Multidetector CT: an Additional Merit of Thinner Coronal Reformations

OBJECTIVE: We wanted to validate the additional merit of the thinner coronal reformation images from multidetector CT (MDCT) for making the diagnosis of hepatic cysts. MATERIALS AND METHODS: For the 90 benign hepatic cysts confirmed on MRI, the transverse (5-mm thickness) and additional coronal (2-mm thickness) reformation images from MDCT were compared with each other in terms of the Hounsfield units (HUs) and the size of each hepatic cyst. RESULTS: The attenuations (mean: 17.2 HUs, standard deviation: +/- 14.4) on the thinner coronal images were significantly lower than those (mean: 40.7 HUs; standard deviation: +/- 20.6) on the thicker transverse images for the small hepatic cysts (< or = 10 mm on the transverse image, p < 0.01). Twenty-three (79%) of the 29 cysts between 5 mm and 10 mm and 21 (51%) of 41 lesions up to 5 mm showed a mean HU value of 20 or less on the coronal reformation images. CONCLUSION: By reducing the partial volume effect, routine coronal reformation of MDCT with a thinner section thickness can provide another merit for making a confidential diagnosis of many small sub-centimeter hepatic cysts, and these small cysts are not easily characterized on the conventional transverse images.

Focal Liver Lesion Detection in Gadoxetic Acid-enhanced Liver MRI: Effects of Scan Delay, Hepatic Function, and Magnetic Field Strength

PURPOSE: To determine the effects of scan delay, hepatic function, and magnetic field strength on the performance of gadoxetic acid enhanced magnetic resonance imaging. MATERIALS AND METHODS: Gadoxetic acid enhanced MRI conducted in 72 patients with 10 minutes and 20 minutes delay were reviewed retrospectively. For quantitative analysis, liver-to-lesion signal difference ratio (SDR) was measured and compared according to scan delay time, hepatic function and magnetic field strength. For qualitative analysis, two board-certificated radiologists reviewed 10-minute delay and 20-minute delay images. The sensitivity and specificity of each reader was compared. RESULTS: The SDR of 20-minute images in non-cirrhotic patients was significantly higher (p 0.05) to 10-min delay images. In comparisons according to the magnetic strength, there was no significant difference between 1.5-T and 3.0-T systems. Comparisons of ROC curves showed no statistically significant differences in sensitivity and specificity between 10-minute and 20-minute delay images. CONCLUSION: An increase in the liver-to-lesion signal difference ratio was dependent on the patients' hepatic function but not dependent on the magnetic strength. There was no significant difference in sensitivity or specificity between the 10-minute and 20-minute delay images.

A Case of Mass-Forming Splenic Tuberculosis: MRI Findings with Emphasis of Diffusion-Weighted Imaging Characteristics

Tuberculosis remains one of the most prevalent and fatal infectious diseases in spite of considerable improvements in medical science. The diagnosis and treatment of extrapulmonary tuberculosis involving the abdomen is still complicated owing to vague or non-specific clinical features. Although rare, isolated splenic involvement is one of the important manifestations of extrapulmonary tuberculosis, and imaging suspicion of the disease is essential. We report a case of surgically confirmed mass-forming splenic tuberculosis showing a layered pattern consisting of caseous necrosis with profound restriction of water molecules surrounded by an irregular rind of granulation tissue with less diffusion restriction on diffusion-weighted magnetic resonance imaging (DWI). In the differential diagnosis of neoplastic or non-neoplastic mass-forming lesions involving the spleen, this unique DWI feature could be helpful in characterizing splenic tuberculosis. The patient has been in clinically disease free status for nearly 20 months after splenectomy.

Segmental Difference of the Hepatic Fibrosis from Chronic Viral Hepatitis due to Hepatitis B versus C Virus Infection: Comparison Using Dual Contrast Material-Enhanced MRI

OBJECTIVE: We wanted to identify the geographic differences in hepatic fibrosis and their associations with the atrophy-hypertrophy complex in patients with chronic viral hepatitis using the dual-contrast material-enhanced MRI (DC-MRI) with gadopentetate dimeglumine and ferucarbotran. MATERIALS AND METHODS: Patients with chronic C (n = 22) and B-viral hepatitis (n = 35) were enrolled for determining the subjective grade of fibrosis (the extent and thickness of fibrotic reticulations) in the right lobe (RL), the caudate lobe (CL), the medial segment (MS) and the lateral segment (LS) of the liver, with using a 5-grade scale, on the gradient echo T2*-weighted images of DC-MRI. The fibrosis grades of different segments were compared using the Kruskal-Wallis test followed by post-hoc analysis to establish the segment-by-segment differences. The incidences of two pre-established morphologic signs of cirrhosis were also compared with each other between the two groups of patients. RESULTS: There were significant intersegmental differences in fibrosis grades of the C-viral group (p = 0.005), and the CL showed lower fibrosis grades as compared with the grades of the RL and MS, whereas all lobes were similarly affected in the B-viral group (p = 0.221). The presence of a right posterior hepatic notch was significantly higher in the patients with intersegmental differences of fibrosis between the RL and the CL (19 out of 25, 76%) than those without such differences (6 out of 32, 19%) (p < 0.001). An expanded gallbladder fossa showed no significant relationship (p = 0.327) with the segmental difference of the fibrosis grades between the LS and the MS. CONCLUSION: The relative lack of fibrosis in the CL with more advanced fibrosis in the RL can be a distinguishing feature to differentiate chronic C-viral hepatitis from chronic B-viral hepatitis and this is closely related to the presence of a right posterior hepatic notch.

The Differential Imaging Features of Fat-Containing Tumors in the Peritoneal Cavity and Retroperitoneum: the Radiologic-Pathologic Correlation

There are a variety of fat-containing lesions that can arise in the intraperitoneal cavity and retroperitoneal space. Some of these fat-containing lesions, such as liposarcoma and retroperitoneal teratoma, have to be resected, although resection can be deferred for others, such as adrenal adenoma, myelolipoma, angiomyolipoma, ovarian teratoma, and lipoma, until the lesions become large or symptomatic. The third group tumors (i.e., mesenteric panniculitis and pseudolipoma of Glisson's capsule) require medical treatment or no treatment at all. Identifying factors such as whether the fat is macroscopic or microscopic within the lesion, the origin of the lesions, and the presence of combined calcification is important for narrowing the differential diagnosis. The development and wide-spread use of modern imaging modalities make identification of these factors easier so narrowing the differential diagnosis is possible. At the same time, lesions that do not require immediate treatment are being incidentally found at an increasing rate with these same imaging techniques. Thus, the questions about the treatment methods have become increasingly important. Classifying lesions in terms of the necessity of performing surgical treatment can provide important information to clinicians, and this is the one of a radiologist's key responsibilities.

Ferucarbotran-Enhanced Hepatic MRI at 3T Unit: Quantitative and Qualitative Comparison of Fast Breath-hold Imaging Sequences

PURPOSE: To compare the relative values of various fast breath-hold imaging sequences for superparamagnetic iron-oxide (SPIO)-enhanced hepatic MRI for the assessment of solid focal lesions with a 3T MRI unit. MATERIALS AND METHODS: 102 consecutive patients with one or more solid malignant hepatic lesions were evaluated by spoiled gradient echo (GRE) sequences with three different echo times (2.4 msec [GRE_2.4], 5.8 msec [GRE_5.8], and 10 msec [GRE_10]) for T2*-weighted imaging in addition to T2-weighted turbo spin echo (TSE) sequence following intravenous SPIO injection. Image qualities of the hepatic contour, vascular landmarks and artifacts were rated by two independent readers using a four-point scale. For quantitative analysis, contrast-to-noise ratio (CNR) was measured in 170 solid focal lesions larger than 1 cm (107 hepatocellular carcinomas, nine cholangiocarcinomas and 54 metastases). RESULTS: GRE_5.8 showed the highest mean points for hepatic contour, vascular anatomy and imaging artifact presence among all of the subjected sequences (p<0.001) and was comparable (p=0.414) with GRE_10 with regard to lesion conspicuity. The mean CNRs were significantly higher (p<0.001) in the following order: GRE_10 (24.4+/-14.5), GRE_5.8 (14.8+/-9.4), TSE (9.7+/-6.3), and GRE_2.4 (7.9+/-6.4). The mean CNRs of CCCs and metastases were higher than those of HCCs for all imaging sequences (p<0.05). CONCLUSION: Regarding overall performances, GRE using a moderate echo time of 5.8 msec can provide the most reliable data among the various fast breath-hold SPIO-enhanced hepatic MRI sequences at 3T unit despite the lower CNR of GRE_5.8 compared to that of GRE_10.

Ferucarbotran-Enhanced Hepatic MRI at 3T Unit: Quantitative and Qualitative Comparison of Fast Breath-hold Imaging Sequences

PURPOSE: To compare the relative values of various fast breath-hold imaging sequences for superparamagnetic iron-oxide (SPIO)-enhanced hepatic MRI for the assessment of solid focal lesions with a 3T MRI unit. MATERIALS AND METHODS: 102 consecutive patients with one or more solid malignant hepatic lesions were evaluated by spoiled gradient echo (GRE) sequences with three different echo times (2.4 msec [GRE_2.4], 5.8 msec [GRE_5.8], and 10 msec [GRE_10]) for T2*-weighted imaging in addition to T2-weighted turbo spin echo (TSE) sequence following intravenous SPIO injection. Image qualities of the hepatic contour, vascular landmarks and artifacts were rated by two independent readers using a four-point scale. For quantitative analysis, contrast-to-noise ratio (CNR) was measured in 170 solid focal lesions larger than 1 cm (107 hepatocellular carcinomas, nine cholangiocarcinomas and 54 metastases). RESULTS: GRE_5.8 showed the highest mean points for hepatic contour, vascular anatomy and imaging artifact presence among all of the subjected sequences (p<0.001) and was comparable (p=0.414) with GRE_10 with regard to lesion conspicuity. The mean CNRs were significantly higher (p<0.001) in the following order: GRE_10 (24.4+/-14.5), GRE_5.8 (14.8+/-9.4), TSE (9.7+/-6.3), and GRE_2.4 (7.9+/-6.4). The mean CNRs of CCCs and metastases were higher than those of HCCs for all imaging sequences (p<0.05). CONCLUSION: Regarding overall performances, GRE using a moderate echo time of 5.8 msec can provide the most reliable data among the various fast breath-hold SPIO-enhanced hepatic MRI sequences at 3T unit despite the lower CNR of GRE_5.8 compared to that of GRE_10.

Prostate Cancer: Added Value of Subtraction Dynamic Imaging in 3T Magnetic Resonance Imaging with a Phased-array Body Coil

PURPOSE: To determine the added value of dynamic subtraction magnetic resonance (MR) imaging for the localization of prostate cancer. MATERIALS AND METHODS: We examined 21 consecutive patients who underwent MR imaging in 3T unit with a phased-array body coil and then had radical prostatectomy. After T2-weighted fast spin-echo imaging, we performed a contrast-enhanced dynamic 3D gradient-echo imaging consisting of pre-contrast, 2 successive early-phased (first imaging was started just after the appearance of contrast material in the aortic bifurcation followed by second imaging 35 seconds after the initiation of first imaging) and one 5-minute delayed post-contrast series. Subtraction of pre-contrast images from corresponding post-contrast images of each phase was performed on the console. RESULTS: On ROC analysis, the overall accuracy (Az value) of dynamic imaging combined with subtraction imaging was higher than T2-weighted imaging (p = 0.001) or conventional dynamic imaging alone (p = 0.074) for localization of cancer foci regardless of their zonal locations. Among pathologically verified 81 lesions, the mean volume of detected lesions with the subtraction images (n = 49, 0.69cm3) was smaller than with T2-weighted images (n = 14, 1.05cm3) or conventional dynamic images (n = 43, 0.71cm(3)). CONCLUSION: For localization of small prostate cancer, additional subtraction for the dynamic imaging could be superior to both T2-weighted imaging and un-subtracted dynamic imaging.

Reassessment of the Usefulness of 18F-FDG PET in the Evaluation of Adrenal Masses Detected on CT or MR

PURPOSE: To reassess the usefulness of 18F-FDG PET in the differential diagnosis of benign and malignant tumors from adrenal masses detected on CT or MR. MATERIALS AND METHODS: A retrospective analysis was performed on 20 patients (n = 21), on whom PET scans were obtained with characteristically benign CT (n = 21) and MR (n = 2) findings. Seventeen patients had a proven primary malignancy and three patients had adrenal incidentalomas. PET findings were interpreted as positive if the 18F-FDG uptake of the adrenal mass was greater than or equal to that of the liver. Each adrenal mass was characterized by its size and standardized uptake value (SUV). For statistical analysis, the t-test was used to analyze results for size and SUV. RESULTS: PET findings were positive for eight adrenal masses; two masses were pathologically proven as adrenocortical oncocytomas. The false positive rate was 38% in all patients and 41% in patients with a malignancy. CONCLUSION: 18F-FDG PET was useful in evaluating the primary lesions as well as metastases, but a high false positive rate in patients with a primary malignancy should be considered in the diagnosis of metastasis to the adrenal gland.

Nonleukemic Granulocytic Sarcoma of the Ileum: A Case Report

Granulocytic sarcoma is an uncommon clinical condition that usually occurs in the bone, periosteum, soft tissue, lymph node and skin, and this is rarely seen in the gastrointestinal tract. To the best of our knowledge, few cases of granulocytic sarcoma in the small bowel have been reported in the English literature. We present here a case of nonleukemic granulocytic sarcoma of the ileum in a 42-year-old patient who had no evidence of blood or bone marrow involvement that would have been suggestive of acute leukemia or myeloproliferative disorders.

Usefulness of Colon Transit Time and Defecography in Patients with Chronic Constipation

PURPOSE: We wanted to evaluate whether both the colonic transit time (CTT) and defecography are necessary for diagnosing constipated patients, and we also wanted to assess the defecographic findings of patients with outlet obstruction on CTT. MATERIALS AND METHODS: Over the recent 3 years, 26 patients (21 women and 5 men, mean age: 59 years) underwent both CTT and defecography because of their chronic constipation or defecation difficulty. The mean interval between the 2 studies was 48 days. Colonoscopy, barium enema and manometry were performed in 22, 8 and all the patients, respectively. RESULTS: On CTT, 13 patients (50.0%) were normal and 13 patients (50.0%) were abnormal; the abnormal results were composed of outlet obstruction (n=8, 30.8%), outlet obstruction and colon inertia (n=2, 7.7%), colon inertia (n=2, 7.7%), and outlet obstruction and hindgut dysfunction (n=1, 3.8%). On defecography, 6 patients (23.1%) were normal and 20 patients (76.9%) were abnormal; the results were composed of rectocele (n=8, 30.7%), rectocele and perineal descent syndrome (PDS; n=4, 15.4%), PDS and rectal intussusception (n=3, 11.5%), spastic pelvic floor syndrome (SPFS; n=3, 11.5%), rectocele and SPFS (n=1, 3.8%), and rectal intussusception (n=1, 3.8%). Of the 11 patients with outlet obstruction on CTT, rectocele (n=4, 36.4%), SPFS (n=1, 9.1%), rectocele and PDS (n=1, 9.1%), and PDS and rectal intussusception (n=1, 9.1%) were demonstrated on defecography, except for the 4 normal cases. CONCLUSION: Both CTT and defecography were necessary for diagnosing the patients with chronic constipation in compensation, and 63.6% of the patients with pelvic outlet obstruction showed an abnormal pelvic defecation function.