Comparison of long-labeled pseudo-continuous arterial spin labeling (ASL) features between young and elderly adults: special reference to parameter selection.

BACKGROUND: The signal intensity obtained by arterial spin labeling (ASL) depends not only on perfusion signal, but also on arterial transit time (ATT). Although ATT has a more significant effect on accurate regional cerebral blood flow (CBF) calculations, the multiple post-labeling delay (PLD) approach is difficult to use in routine examinations. PURPOSE: To optimize imaging parameters for labeling duration (LD) and PLD and to confirm their validity in long-labeled pseudo-continuous ASL. MATERIAL AND METHODS: The perfusion signal was simulated in four LDs and theoretical signal-to-noise ratio efficiency (SNReff) was calculated. In vivo studies were performed on a 3.0 T magnetic resonance imaging (MRI) scanner and 15 volunteers were categorized into either the young or elderly adult groups. We compared the differences in CBF values with or without ATT correction. RESULTS: Regarding signal simulation, perfusion signal increased with the length of LD. SNReff also improved with LD, but SNReff plateaued at an LD of 3.0 s. As for the in vivo study, SNR linearly increased along with the LD. The CBF differences with the correction of ATT were larger in the elderly adult group. This trend was most prominent in the longer ATT area in the occipital cortical region. CONCLUSION: A combination of imaging settings of LD = 3.5 s and PLD = 2.0 s were suggested as optimal imaging parameters for allowing acceptable CBF quantification and sufficient SNR in both young and elderly individuals.

Serial changes of (18)F-FDG PET/CT findings in ischiopubic synchondrosis: comparison with contrast-enhanced MRI.

UNLABELLED: A 3 years old female patient underwent resection and chemotherapy for a yolk sac tumor of the retroperitoneum. Two years later, fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) showed high uptake in the right ischiopubic synchondrosis (IPS), which had a radiolucent structure on CT. The structure showed contrast enhancement on magnetic resonance imaging (MRI), which was a non-specific finding. Six weeks later, a follow-up (18)F-FDG PET/CT scan was performed which showed no abnormal uptake in the IPS. The disappearance of (18)F-FDG uptake preceded that of contrast enhancement on MRI, which was seen 7 months after the initial (18)F-FDG PET/CT scan. CONCLUSION: This is the first report showing serial changes of (18)F-FDG uptake in IPS, in comparison to MRI findings.

Standardized uptake value differences between primary and metastatic lesions in ¹8F-FDG PET/CT of patients with lung cancer.

BACKGROUND: FDG-PET/CT is a robust tool for staging of lung cancer, but the differences in FDG uptake between primary and metastatic lesions have not yet been well described. PURPOSE: To define the potential range of standardized uptake value (SUV) differences between primary and metastatic lesions in lung cancer patients and to identify the factors responsible for these differences. MATERIAL AND METHODS: FDG-PET/CT images of 75 lung cancers with 296 metastases were analyzed retrospectively. Histological types, primary locations, and metastatic sites were recorded. The average and maximum SUV (SUVavg, SUVmax) of each primary tumor and metastasis were measured, and the ratio of metastatic SUVs to primary SUVs (M/Pavg, M/Pmax), its difference from 100% (diff-M/Pavg, diff-M/Pmax), the ratio of ROI area of metastatic to primary lesions (ROI-M/P), and its difference from 100% (diff-ROI-M/P) were calculated. RESULTS: M/Pavg was in the range of 35.9-224.6% (mean ± SD: 97.9% ± 35.9%), while M/Pmax was in the range of 24.8-286.7% (98.1% ± 45.3%). Furthermore, values were in the range of 50-200% for M/Pavg in 280/296 lesions (94.6%) and for M/Pmax in 255/296 lesions (86.1%). M/Pavg and M/Pmax showed significant linear correlations with ROI-M/P (r = 0.62, 0.64, respectively). Multivariate analysis showed that diff-ROI-M/P had the greatest effect on diff-M/Pavg and diff-M/Pmax. CONCLUSION: The SUVs of most metastatic lesions ranged from half to double those of primaries in lung cancer patients. When the SUV of a suspected metastasis is beyond the range of half to double that of the primary lung cancer, other non-metastatic lesions should be considered, while taking ROI size into account.

Evaluation of staging and early response to chemotherapy with whole-body diffusion-weighted MRI in malignant lymphoma patients: A comparison with FDG-PET/CT.

BACKGROUND: To examine the utility of diffusion-weighted MRI (DW-MRI) for staging and early response to chemotherapy assessment in lymphoma patients as compared with fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT). METHODS: Twenty-eight patients with histologically confirmed malignant lymphoma underwent both MRI and FDG-PET/CT before (pretreatment) and after two courses of chemotherapy (mid-treatment). Staging with MRI (DW-MRI alone and with T2-weighted images) and FDG-PET was compared visually, and the concordance rate (kappa value, κ) was calculated. To evaluate early response to chemotherapy, patients were divided into two groups, lesion-positive (LP) and lesion-negative (LN), based on a proposed original criterion. Progression-free survival (PFS) was compared between the groups using the Kaplan-Meier method. RESULTS: The stage diagnosed with DW-MRI alone and with FDG-PET/CT was concordant in 22 patients (κ = 0.71; P < 0.05), and by adding T2-weighted images, the number of concordant patients increased to 26 (κ = 0.90; P < 0.05). On mid-treatment imaging, 19 patients were diagnosed as LN from both modalities. PFS differed significantly between LP and LN on both DW-MRI (P = 0.0013) and FDG-PET/CT (P = 0.037). CONCLUSION: DW-MRI is a promising tool for staging and evaluation of early response to chemotherapy in patients with lymphoma.

Variations in feeding arteries of hepatocellular carcinoma located in the left hepatic lobe.

The left hepatic lobe is divided into three subsegments according to anatomical landmarks; however, there are several variations in the vascular territories of the left hepatic arterial branches. Hepatocellular carcinoma (HCC) located near the umbilical fissure or at the left side of the umbilical portion of the left portal vein has frequent crossover blood supply. HCC located in the caudal aspect of the lateral segment has a variety of feeding arteries, and is infrequently supplied by the caudate artery or the medial subsegmental artery (A4), and by the lateral left hepatic arteries. HCC located in the posterior aspect of segment 4 is frequently supplied by the caudate artery or a small A4 branch arising from the caudate artery. In addition, the left inferior phrenic, right and left internal mammary, right and left gastric, cystic, and omental arteries are well known extrahepatic collateral pathways supplying HCC in the left hepatic lobe, especially when the hepatic artery is attenuated by previous transcatheter arterial chemoembolization (TACE). Interventional radiologists should have sufficient knowledge of vascular territories in the left hepatic arterial branches and extrahepatic collaterals to perform effective TACE for HCC located in the left hepatic lobe.

Comparison of local control effects of superselective transcatheter arterial chemoembolization using epirubicin plus mitomycin C and miriplatin for hepatocellular carcinoma.

PURPOSE: To compare local control effects of superselective transcatheter arterial chemoembolization (TACE) using epirubicin (EPI) plus mitomycin C (M) and miriplatin (MPT) for hepatocellular carcinoma (HCC). MATERIALS AND METHODS: One-hundred and twenty-nine HCCs treated with superselective TACE were divided into three groups according to the type of anticancer drug; EPI-M-TACE (n = 51), MPT-TACE (n = 21), and MPT-I-TACE (MPT emulsion) (n = 57). Local recurrence, patterns of recurrence (intratumoral recurrence; IR), and follow-up angiograms were evaluated. RESULTS: Mean tumor diameter and follow-up period for the EPI-M-TACE, MPT-TACE, and MPT-I-TACE groups were 16.9 mm and 15.5 months, 20.7 mm and 12.0 months, and 18.8 mm and 9.6 months, respectively. Local recurrence for the EPI-M-TACE, MPT-TACE, and MPT-I-TACE groups at 5, 10, and 15 months was 6.1, 47.6, and 40.1%, 23.5, 67.3, and 63.9%, and 26.2, 75.4, and 72.9%, respectively. IR for the EPI-M-TACE, MPT-TACE, and MPT-I-TACE groups was 23.1, 71.4, and 71.0%, respectively. Local recurrence and IR in the EPI-M-TACE group were significantly less than those in the MPT-TACE and MPT-I-TACE groups. Follow-up angiograms revealed less arterial damage in the MPT-TACE and MPT-I-TACE groups. CONCLUSION: Superselective TACE using MPT resulted in very frequent local recurrence, in particular IR, despite less arterial damage.

Origins of feeding arteries of hepatocellular carcinoma located near the umbilical fissure of the left hepatic lobe: angiographic evaluation.

PURPOSE: To analyze the origins of the feeding arteries of hepatocellular carcinomas (HCCs) near the umbilical fissure of the left hepatic lobe. METHODS: Twenty-eight HCCs with a mean ± SD tumor diameter of 3.4 ± 1.0 cm (range 1-4.4 cm) in contact with the right or left side of the umbilical fissure were treated by superselective transcatheter arterial chemoembolization (TACE). The origins of the tumor-feeding arteries were analyzed with arteriograms and computed tomography or cone-beam computed tomography images obtained during and 1 week after TACE. RESULTS: Twenty-one HCC lesions were located in segment 3 and seven were located in segment 4. Of 21 tumors in segment 3, 13 (61.9%) were supplied by the lateral inferior subsegmental artery (A3), three (14.3%) by the medial subsegmental artery (A4), three (14.3%) by both A4 and A3, one (4.8%) by a branch arising from the left lateral hepatic artery, and one (4.8%) by a branch of the right gastric artery. In particular, all tumor-feeding branches arising from A4 were the first branch of A4. Of seven tumors in segment 4, four (57.1%) were supplied by A4 and three (42.9%) by A3. In particular, all tumor-feeding branches arising from A3 were the first branch of A3. CONCLUSION: This study demonstrates crossover blood supply to HCC lesions located near the umbilical fissure, in addition to direct feeding from a separate branch. In particular, the first branch of the opposite subsegmental artery may feed tumors when crossover blood supply is present.

Arterial blood supply to the caudate lobe of the liver from the proximal branches of the right inferior phrenic artery in patients with recurrent hepatocellular carcinoma after chemoembolization.

PURPOSE: To evaluate the arterial blood supply to the caudate lobe of the liver from the proximal branches of the right inferior phrenic artery (RIPA) in patients with recurrent hepatocellular carcinoma after transcatheter arterial chemoembolization (TACE). MATERIALS AND METHODS: Thirteen patients, including 10 who had a history of TACE of the caudate artery (A1), underwent TACE of the proximal RIPA branches. Iodized oil distribution was evaluated by computed tomography (CT) 1-week after TACE. Angiographic findings were also evaluated. RESULTS: Previously embolized A1 was occluded (n = 15) or attenuated (n = 2). In one of three patients without A1 TACE, A1 was also attenuated. TACE was performed at the first branch of the proximal RIPA (n = 8), the first branch of the anterior branch (n = 6), and the first branch of the posterior branch (n = 1), respectively. Iodized oil was mainly distributed into the dorsal part of the Siegel lobe (SP) (n = 10), the caudate process (n = 1), and both (n = 2). In three of seven patients who had undergone serial RIPA angiography, RIPA parasitization to SP was suspected before A1 TACE. CONCLUSION: The proximal RIPA branches mainly supply the SP when A1 is attenuated.

Thrombolysis and thromboaspiration for acute thromboembolic occlusion in the upper extremity.

PURPOSE: To report technical aspects of thrombolysis and thromboaspiration for acute thromboembolic occlusion in the upper extremity. MATERIALS AND METHODS: This study included four consecutive patients with acute thromboembolic occlusion in the upper extremity (right arm, n = 3; left arm n = 1). The mean patient age was 81.3 ± 11.5 years (mean ± standard deviation; range 69-92 years) and all patients had chronic atrial fibrillation. Emergent angiography was performed via the femoral artery. RESULTS: Thromboembolic occlusion was demonstrated in the axillary artery (n = 2), axillary and radial arteries (n = 1), and brachial, radial, and ulnar arteries (n = 1). Endovascular treatment was performed via the unaffected brachial (n = 3) or radial artery (n = 1). Thrombolysis was performed for three patients using 360,000-480,000 IU (mean 400,000 ± 69,000 IU) urokinase, including 12-h continuous infusion in one. Thromboaspiration was performed in all four patients using a 6F catheter. Recanalization was achieved in all patients and all arms were salvaged. Perforation of the small branch during guidewire manipulation was successfully managed by placement of a microcoil. CONCLUSION: The combination of thrombolysis and thromboaspiration is effective for acute thromboembolic occlusion in the upper extremity.

Usefulness of C-arm CT during superselective infusion chemotherapy for advanced head and neck carcinoma.

PURPOSE OF THE STUDY: To evaluate the usefulness of C-arm computed tomography (CT) during superselective intra-arterial infusion chemotherapy for advanced head and neck carcinoma. METHODS: C-arm CT was performed during superselective intra-arterial infusion chemotherapy for 11 patients with advanced head and neck carcinoma located in the hypopharynx (n = 3), maxillary sinus (n = 3), oropharynx (n = 1), larynx (n = 1), extra-auditory canal (n = 1), tonsil (n = 1) and tongue (n = 1). The usefulness of C-arm CT during superselective catheterisation was evaluated. RESULTS: On arteriography, nine tumours showed tumour stains and two in the oropharynx or tonsil showed no obvious tumour stains. C-arm CT was performed one to four times (mean ± standard deviation, 2.5 ± 0.8) in each patient during a single procedure. C-arm CT clearly showed not only the vascular territory of the selected branch but also the tumour itself in all patients. Intra-arterial infusion chemotherapy was performed through one to three branches (mean, 1.7 ± 0.9) according to C-arm CT findings without any complications. CONCLUSION: C-arm CT during superselective intra-arterial infusion chemotherapy was useful to determine the arterial supply of head and neck carcinoma. C-arm CT may replace conventional CT during superselective arteriography in this procedure.

Kikuchi-Fujimoto disease: PET/CT assessment of a rare cause of cervical lymphadenopathy.

PURPOSE: Kikuchi-Fujimoto disease (KFD), formerly called subacute necrotizing lymphadenitis, is a rare cause of cervical lymphadenopathy. The purpose of this study was to evaluate the usefulness of FDG PET/CT for distinguishing KFD from non-Hodgkin lymphoma (NHL). MATERIALS AND METHODS: Twenty-two patients with cervical lymphadenopathy (8 with KFD and 14 with NHL) underwent CT and FDG PET/CT scans to examine the cervical lymphadenopathy. Regional values of FDG uptake were evaluated using the standardized uptake value (SUV) and partial volume corrected SUV (corSUV) based on the count recovery coefficient. Tumor size (mm), SUV, and corSUV were compared among KFD, indolent NHL, and aggressive NHL. RESULTS: KFD lesions tended to be smaller (13.8 ± 5.4 mm) than those of indolent (25.4 ± 11.8) and aggressive (29.7 ± 18.8) NHL, whereas there were no significant differences in size. As for SUV, a significant difference was observed only between indolent and aggressive (6.4 ± 1.5 and 17.3 ± 9.3, P < 0.05) NHL; however, KFD showed a significantly greater corSUV (23.8 ± 10.6) as compared with indolent NHL (9.2 ± 5.1, P < 0.05), which did not show a significant difference from aggressive NHL (21.4 ± 10.2). FDG PET/CT detected thoracoabdominal lesions in 2 patients (25%) with KFD. CONCLUSIONS: KFD shows high FDG uptake for size, which may reflect the pathologic characteristics, including necrotizing lymphocytes and numerous histiocytes (macrophages) surrounding small necrotic foci. FDG PET/CT will be useful for detecting noncervical lesions of KFD and distinguishing KFD from NHLs using both SUV and corSUV.

Efficacy of cone-beam computed tomography during transcatheter arterial chemoembolization for hepatocellular carcinoma.

Cone-beam computed tomography (CBCT) using a flat-panel detector is an alternative method of obtaining cross-sectional images. This technique is now being used during transcatheter arterial chemoembolization (TACE) for inoperable hepatocellular carcinoma (HCC). Several CBCT techniques are performed to detect HCC lesions: CBCT during portography (CBCTAP), CBCT during hepatic arteriography (CBCTHA), CBCT after iodized oil injection (LipCBCT), CBCT during arteriography (CBCTA) of extrahepatic collaterals. Almost all HCC lesions can be detected using these CBCT images. Three-dimensional arteriography using maximum intensity projection from CBCTHA images can identify the tumor-feeding branch. In particular, this technique is useful when the tumor stain cannot be demonstrated on arteriography. In addition, dual-phase CBCTHA can improve the diagnostic accuracy for hypervascular HCCs because corona enhancement can be detected around the tumor. To monitor the embolized area during TACE, selective CBCTHA or LipCBCT at the embolization point is useful. Two sequential CBCT scans without and with contrast material injection is also useful to confirm each embolized area of two vessels. Furthermore, CBCTA can prevent nontarget embolization. Although the image quality of CBCT is low compared to that of conventional CT, CBCT provides useful information that helps perform TACE for HCCs safely and effectively.

Portal blood supply to locally progressed hepatocellular carcinoma after transcatheter arterial chemoembolization: Observation on CT during arterial portography.

AIM: To analyze the clinical features of locally progressed hepatocellular carcinoma (HCC) supplied by portal blood (PB) after transcatheter arterial chemoembolization (TACE). METHODS: This cohort included 12 tumors (mean diameter ± SD, 1.8 ± 0.8 cm) in 10 patients. PB supply to tumors was judged by CT during arterial portography (CTAP). Imaging data and the clinical course were retrospectively evaluated. RESULTS: Six tumors initially had a small tumor portion supplied by PB. In four tumors, TACE was incomplete because of technical problems. PB supply to recurrent tumors was demonstrated 7.3 ± 3.7 months after TACE. On follow-up arteriography, all embolized branches were occluded or severely attenuated. Four tumors showing a partial stain were treated by additional TACE (n = 3) or TACE plus radiofrequency (RF) ablation (n = 1), one without staining was treated by RF ablation, and seven were followed-up. All tumors progressed except for one treated by RF ablation. On serial CTAP images, relatively large-diameter portal veins directly entered 11 tumors (91.7%) and connected with intratumoral vessels in nine (75%). During follow-up, partial arterial supply was demonstrated in two tumors and additional TACE was performed. Nine patients died after 31.4 ± 16.2 months due to tumor progression (n = 8), or hepatic failure (n = 1). One patient has survived for 53 months despite multiple tumors. CONCLUSIONS: PB supply to locally progressed tumor after TACE became apparent on CTAP. Arterial damage by TACE, incomplete TACE, and preexisting tumor tissues supplied by PB may be the main causes.

Microcoil embolization during abdominal vascular interventions through microcatheters with a tip of 2 French or less.

PURPOSE: The aim of this study was to evaluate the technical aspects of embolization using microcoils through a microcatheter with a tip of 2F or smaller during abdominal vascular interventions. MATERIALS AND METHODS: Coil embolization through a microcatheter with a tip of 2F or smaller was attempted in 73 procedures. Two types of microcoil-Liquid Coil (Boston Scientific, Watertown, MA, USA) and Tornado Coil (Cook, Bloomington, IN, USA)-were deployed through four types of thinner microcatheter [2F tip (n = 49) and 1.8F tip (n = 24)]. Coil jams in the microcatheter and coil migration were evaluated. RESULTS: In total, 286 microcoils were placed (mean ± SD, 3.9 ± 4.3 coils per procedure, range 1-32 coils). In 19 procedures (26.9%), Liquid Coils were used alone. In 44 (60.3%), Tornado Coils were used alone. In 10 (13.7%), Liquid Coils and Tornado Coils were combined. There were no coil jams in the microcatheter in this series. One Tornado Coil (0.3%) delivered into the gastroduodenal artery migrated to the right hepatic artery. CONCLUSION: Liquid Coils and Tornado Coils can be placed through a thinner microcatheter without difficulty. However, there is a risk of coil migration in large vessels or at the proximal site because the catheter tip is not stabilized.

Angiographic evaluation of feeding arteries of hepatocellular carcinoma in the caudate lobe of the liver.

PURPOSE: To evaluate the origins of feeders of hepatocellular carcinoma (HCC) in the caudate lobe (S1). MATERIALS AND METHODS: Eighty-eight HCCs (mean diameter 21.4 mm) were treated by chemoembolization. The tumor-feeding caudate artery was confirmed when a tumor stain was demonstrated on angiogram and iodized oil was accumulated into the HCC and S1 on computed tomography (CT). The origins were divided into R(1) (right proximal), R(2) (right distal), L(1) (left proximal), L(2) (left distal), A (anterior segmental), P (posterior segmental), M (middle hepatic or medial segmental), Ph (proper hepatic), Ch (common hepatic), and Ex (extrahepatic). The origins of feeders supplying HCCs in the Spiegel lobe (SP; n = 36), the paracaval portion (PC; n = 38), and the caudate process (CP; n = 14) were also analyzed. RESULTS: One hundred sixteen feeders were identified: 11 (9.5%) arose from R(1); 21 (18.1%) arose from R(2); nine arose (0.9%) from L(1); 15 (12.9%) arose from L(2); 24 (20.7%) arose from A; 25 (21.6%) arose from P; seven (6.0%) arose from M; one (0.9%) arose from Ph; and three (2.6%) arose from Ex. HCCs in the SP and the PC were fed by feeders from both hepatic arteries (the ratios of right to left were 3:2 and 3:1, respectively), and HCCs in the CP were dominantly fed by feeders from the right hepatic artery. CONCLUSION: The caudate artery most frequently arises from the right hepatic artery, followed with almost equal frequency by the left hepatic, the anterior segmental, and the posterior segmental artery. The origins of the caudate arteries differ according to the subsegmental locations.