Fumiyasu Tsushima

Incidental prostate 18F-FDG uptake without calcification indicates the possibility of prostate cancer

Incidental 18F-fluorodeoxyglucose (18F-FDG) uptake in the prostate is often experienced in clinical practice; however, it is difficult to determine whether incidental uptake is indicative of a malignancy or benign state based on the maximum standardized uptake value (SUVmax). In the present study, we investigated the clinical significance of incidental prostate uptake by 18F-FDG positron emission tomography (PET)/CT, and examined the differences between malignant and benign uptake from a clinicopathological viewpoint. We reviewed 3,236 male subjects who underwent 18F-FDG PET/CT scans at Hirosaki University Hospital (Japan) from 2008 to 2012 in order to identify cases of incidental prostate FDG uptake. The final diagnosis was made by serum prostate-specific antigen (PSA) levels, biopsy, imaging studies and clinical follow-up with PET findings. Incidental FDG uptake of the prostate was observed in 53 cases (2%). Four cases were excluded due to insufficient clinical data, and 49 cases were included in the present study. Of the 49 cases, 8 (16%) had prostate cancer, while 41 (84%) were benign. All 8 malignant cases had high uptake areas, e.g. in the prostate peripheral zone, where there was no coexistence of calcification or FDG uptake. Of the 41 benign cases, 19 had high uptake in the inner zone, 17 in the peripheral zone, and 5 in both the inner and peripheral zones. Of the 41 cases, 18 (44%) showed FDG uptake coexisting with prostatic calcification. Incidental prostate 18F-FDG uptake infrequently signifies prostate cancer; however, FDG uptake not coexisting with calcification indicates the possibility of prostate cancer and should be included in the differential diagnosis for performing other clinical examinations.

Incidence of unilateral distal vertebral artery aplasia: evaluation by combining basiparallel anatomic scanning-magnetic resonance imaging (BPAS-MRI) and magnetic resonance angiography

PurposeThe incidence of a unilateral aplastic distal vertebral artery (VA) has been reported as 0.2% of cases on cerebral angiography. During our daily magnetic resonance (MR) examinations, however, we frequently encounter MR angiograms (MRAs) that do not demonstrate unilateral VA. The purpose of this study was to calculate the frequency of aplastic unilateral distal VA by MR images performed for asymptomatic people.Materials and methodsOver a time span of 1 year, 237 asymptomatic people (140 men, 97 women; ages 28–67 years, mean 54.4 years) underwent brain MRI during a “brain check-up examination” in our hospital. To identify an aplastic unilateral distal VA, we retrospectively compared three-dimensional time-of-flight MRA with basiparallel anatomic scanning (BPAS)-MRI which was designed for recognition of the arterial outer contour.ResultsAplasia of the unilateral distal VA was confirmed in 11 persons (4.6%). According to our classification, hypoplastic distal VA in 12 (5.1%) and asymptomatic acquired unilateral distal VA occlusion was also proved in 2 (0.8%).ConclusionWe found that the frequency of aplastic unilateral VA was 4.6% in asymptomatic people using a combination of MRA and BPAS-MRI for assessment of an intracranial VA.

Temporal variations in stump pressure and assessment of images obtained from cone‐beam computed tomography during balloon‐occluded transarterial chemoembolization

Balloon‐occluded transcatheter arterial chemoembolization (B‐TACE) was used to show the optimized duration of balloon occlusion to start injection of lipiodol in order to maximize lipiodol deposition in the nodule, and to reveal the endpoint of lipiodol injection.

Bolus injection of contrast agents with various iodine concentrations and delivery rates for intracranial three-dimensional CT angiography: evaluation of intracranial arteriovenous contrast using a multidetector-row CT scanner

PurposeWe evaluated the difference in computed tomography (CT) attenuation values of the intracranial arterial and venous systems among the various contrast injection protocols (higher iodine delivery rate or higher concentration of the agent) on the source images of intracranial three-dimensional CT angiography (3D-CTA) using a multidetector-row CT (MDCT) scanner.Materials and methodsWe used 100 ml of iopamidol 300 at an injection rate of 3.0 ml/s, 100 ml of iopamidol 300 at an injection rate of 3.7 ml/s, and 80 ml of iopamidol 370 at an injection rate of 3.0 ml/s. There were 10 patients in each group. Attenuation values of the bilateral internal carotid arteries (ICAs), basilar artery trunk, bilateral cavernous sinuses (CSs), and Galenic vein were measured quantitatively on the axial CT angiographic source images obtained by four-channel MDCT.ResultsInjection of the high-concentration contrast with a higher iodine-delivery rate achieved good arteriovenous contrast at the cavernous portion. With the same rate of iodine delivery, injection of the intermediate concentrate agent increased the CT value of not only the ICAs but also the CSs.ConclusionHigh-concentration contrast could increase ICA attenuation without intracavernous attenuation gain during the “first-pass” phase.

Attenuation values of the intracranial arterial and venous vessels by bolus injection of various contrast agents: a study with a single-detector helical CT scanner

PurposeWe evaluated the arteriovenous contrast on the source images of intracranial three-dimensional computed tomography (CT) angiography (3D-CTA) using a high-concentration (370 mg I/ml) contrast agent in comparison with intermediate-concentration (300 mg I/ml) contrast.Materials and methodsWith a fixed intravenous injection rate and scanning delay, 3D-CTA was performed using a single-detector helical CT scanner in 30 consecutive patients. We used 100 ml of iohexol 300 for 10 patients, 100 ml of iopamidol 300 for 10 patients, and 80 ml of iopamidol 370 for 10 patients. Attenuation values of the bilateral internal carotid arteries, bilateral middle cerebral arteries, basilar artery trunk, bilateral cavernous sinuses, bilateral basal veins, and Galenic vein were measured quantitatively on the axial CT angiographic source images.ResultsHigh-concentration contrast significantly increased the attenuation values of the intracranial arterial system without increasing the attenuation of the venous system.ConclusionHigh-concentration contrast is helpful for obtaining valuable arteriovenous contrast on source images with intracranial 3D-CTA.

Impact of pretreatment whole-tumor perfusion computed tomography and 18F-fluorodeoxyglucose positron emission tomography/computed tomography measurements on local control of non-small cell lung cancer treated with stereotactic body radiotherapy.

This study aimed to investigate the correlation between the average iodine density (AID) detected by dual-energy computed tomography (DE-CT) and the maximum standardized uptake value (SUVmax) yielded by [18F] fluorodeoxyglucose positron emission tomography (18F-FDG PET) for non–small cell lung cancer (NSCLC) treated with stereotactic body radiotherapy (SBRT). Seventy-four patients with medically inoperable NSCLC who underwent both DE-CT and 18F-FDG PET/CT before SBRT (50‒60 Gy in 5‒6 fractions) were followed up after a median interval of 24.5 months. Kaplan–Meier analysis was used to determine associations between local control (LC) and variables, including AID, SUVmax, tumor size, histology, and prescribed dose. The median AID and SUVmax were 18.64 (range, 1.18–45.31) (100 µg/cm3) and 3.2 (range, 0.7–17.6), respectively. No correlation was observed between AID and SUVmax. Two-year LC rates were 96.2% vs 75.0% (P = 0.039) and 72.0% vs 96.2% (P = 0.002) for patients classified according to high vs low AID or SUVmax, respectively. Two-year LC rates for patients with adenocarcinoma vs squamous cell carcinoma vs unknown cancer were 96.4% vs 67.1% vs 92.9% (P = 0.008), respectively. Multivariate analysis identified SUVmax as a significant predictor of LC. The 2-year LC rate was only 48.5% in the subgroup of lower AID and higher SUVmax vs >90% (range, 94.4–100%) in other subgroups (P = 0.000). Despite the short follow-up period, a reduction in AID and subsequent increase in SUVmax correlated significantly with local failure in SBRT-treated NSCLC patients. Further studies involving larger populations and longer follow-up periods are needed to confirm these results.

Contribution of dynamic sentinel lymphoscintigraphy images to the diagnosis of patients with malignant skin neoplasms in the upper and lower extremities

The aim of the present study was to confirm the contribution of dynamic images in sentinel lymphoscintigraphy in malignant skin neoplasms: precisely, to investigate if dynamic images were necessary and to observe if dynamic images could reduce the areas needed for biopsy and dissection. Twenty-five patients with malignant skin neoplasms of the lower (n = 21) and upper (n = 4) extremities were retrospectively investigated. Images were evaluated by two independent reviewers, an expert in diagnostic radiology and nuclear medicine and a diagnostic radiologist in training. Visualized hot spots were assessed to be sentinel nodes using only static planar images. Next, both static planar and dynamic images were assessed. Reviewers scored diagnostic confidence values of determined sentinel nodes as follows: 0, cannot be decided; 1, possible; 2, probable; and 3, definitive. Patterns of lymphatic drainage were categorized into six different pathways: (1) inguinal type, (2) popliteal type, (3) inguinal and popliteal type, (4) axillary type, (5) cubital type, and (6) axillary and cubital type. In cases in the lower extremities, with dynamic images, the expert reviewer changed assessment in three cases and the trainee reviewer changed it in one case. There were no cases in which a decision was changed to be the same between both reviewers. Although the average diagnostic confidence value of assessment is usually higher with dynamic images, significant differences were not present. In cases of the upper extremities, both reviewers changed their assessment in one patient. By mutual agreement, cases in which assessment was changed with dynamic images were the inguinal and popliteal type, and the axillary and cubital type. The expert reviewer noticed lymphatic channels only visualized on dynamic images and changed assessment. Determination of whether or not a lymph node is a sentinel node depends on visualization of the lymphatic network. In the present circumstances, all biopsies of hot spots determined to be lymph nodes should not be excluded. However, excessive biopsies should be avoided as much as possible. It is necessary to use dynamic images alongside skillful observation.

Arterial Coil Embolization and Arterialization of the Portal Vein for a Ruptured Hepatic Artery after Partial Hepatectomy

Figure 2. Angiography of celiac artery. Bleeding stopped after coil embolization (arrow). From: Fumiyasu Tsushima, PhD, MD Akihisa Kakuta, MD, PhD Daisuke Kudo, MD, PhD Keinosuke Ishido, MD, PhD Kenichi Hakamada, MD, PhD Departments of Radiology (F.T., A.K.) and Gastroenterological Surgery (D.K., K.I., K.H.) Hirosaki University Graduate School of Medicine 5 Zaifu-cho Hirosaki, Aomori 036-8562, Japan

Interventional Treatment for Giant Hepatic Hemangioma Accompanied by Arterio-portal Shunt with Ascites

A 73-year-old woman with massive ascites associated with a giant hepatic mass accompanied by arterio-portal (AP) shunt was admitted to our hospital. Based on contrast-enhanced computed tomography (CT) and angiography findings, hepatic hemangioma with AP shunt and ascites due to portal hypertension was diagnosed. Transcatheter arterial embolization (TAE) by N-butyl-2-cyanoacrylate (NBCA) was performed without complications. The patients ascites disappeared, and her liver function test results improved after the treatment. The patient has maintained a steady state for two years. This case indicates that TAE with NBCA is a safe and effective treatment for hepatic hemangioma accompanied by AP shunt.

Hypoxia is important in F-18 FDG accumulation in thecoma-fibroma tumors on F-18 FDG PET/CT scans

Several studies have noted benign thecoma-fibroma tumors with positive F-18 fluorodeoxyglucose (FDG) accumulation mimicking malignant ovarian tumors following F-18 FDG positron emission tomography (PET). The present study analyzed four cases with false-positive F-18 FDG PET/computed tomography (CT) diagnoses of thecoma-fibroma tumors as malignant tumors due to F-18 FDG accumulation, compared with eight cases of FDG-positive ovarian cancers and two cases of FDG-negative fibromas. Hypoxia inducible factor (HIF)-1α expression was examined in the six thecoma-fibroma tumors using reverse transcription-polymerase chain reaction (RT-PCR). The four F-18 FDG-positive cases exhibited higher cellularity, maximum standard uptake and signal intensity on T2-weighted imaging, and gadolinium (Gd) enhancement using magnetic resonance imaging than the two FDG-negative fibroma cases. In the F-18 FDG-positive thecoma-fibroma group, Ki-67 expression was low and LAT1 expression was not identified, ruling out the diagnosis and potential for malignancy. However, considerable glucose transporter 1, HIF-1α, and vascular endothelial growth factor expression was observed. HIF-1α expression was elevated in all four false-positive cases by RT-PCR. From these results, it was hypothesized that hypoxia due to elevated cellularity may stimulate HIF-1α expression and be associated with F-18 FDG accumulation in F-18-positive thecoma-fibroma tumors.