Incidence and clinical impact of silent pancreatitis after aortic arch surgery.

BACKGROUND: This study was designed to investigate the incidence and types of pancreatic injury, risk factors, and time-course changes in computed tomographic findings following total aortic arch replacement with moderate hypothermic circulatory arrest. METHODS: Medical records of patients who underwent total arch replacement between January 2006 and August 2021 were retrospectively reviewed. A comparison study between the patients with (group P) and without pancreatic injury (group N) was conducted to elucidate the impact of pancreatic injury. Follow-up computed tomography of the patients in group P was reviewed to investigate time-course changes of the pancreatic injury. RESULTS: Of 353 patients, 14 (4.0%) had subclinical pancreatic injury. Computed tomographic findings were consistent with acute pancreatitis in all patients, of whom eight patients had interstitial edematous pancreatitis, whereas six patients had necrotizing pancreatitis. Although walled-off necrosis occurred in three patients, none of them required drainage. In-hospital mortality was 7.1% and 4.4% in groups P and N, respectively (p = 0.98). The 5-year actuarial survival rates were 77.9% and 81.0% in groups P and N, respectively (p = 0.51). Multivariate analysis revealed that pancreatic injury was associated with chronic obstructive pulmonary disease (p = 0.03). CONCLUSIONS: This study highlighted that silent pancreatic injury after aortic arch surgery is underrecognized. Potential arterial sclerosis of the pancreatic circulation seems to be related to pancreatic injury.

Carbon Dioxide Angiography for the Detection of Lower Gastrointestinal Arterial Bleeding Initially Occult to Angiography with Iodinated Contrast Media.

This study evaluated the utility of carbon dioxide (CO2) in angiography for the detection of lower gastrointestinal arterial bleeding initially occult to angiography with iodinated contrast media. Fourteen patients underwent CO2-enhanced angiography. In all patients, extravasation was identified by contrast-enhanced computed tomography but not by initial iodinated contrast-enhanced angiography. After iodinated contrast-enhanced angiography, CO2-enhanced angiography was performed from the same catheter position. The detection capability for extravasation on CO2-enhanced angiography was evaluated. CO2-enhanced angiography allowed for the visualization of extravasation and subsequent transcatheter arterial embolization in 11 of 14 (79%) cases, with extravasation seen during either CO2-enhanced angiography (n = 8) or subsequent repeat iodinated contrast-enhanced angiography immediately after negative CO2-enhanced angiography (n = 3). Conservative treatment was performed in the remaining 3 cases. In conclusion, CO2-enhanced angiography appears useful for identifying occult lower gastrointestinal bleeding.

Embolization for acute arterial bleeding: use of the triaxial system and N-butyl-2-cyanoacrylate.

PURPOSE: The aim of this study was to evaluate the usefulness of transcatheter arterial embolization (TAE) using the triaxial system with N-butyl-2-cyanoacrylate (NBCA) for acute arterial bleeding in comparison to TAE using the triaxial system with gelatin sponges (GS)　and/or coils. MATERIAL AND METHODS: Between October 2013 and November 2018, 95 patients with acute arterial bleeding underwent emergency TAE using the triaxial system. Six patients underwent multiple TAEs and thus, 104 TAEs using the triaxial system were performed. In 26 of the 104 cases, TAE were performed with NBCA (NBCA group), and in the remaining 78 cases, TAE were performed with GS and/or coils (control group). RESULTS: Hemorrhagic shock and coagulopathy more often occurred in the NBCA group. Procedure time was shorter in the NBCA group. The technical success rate was 100% in both groups (p > 0.99). The clinical success rate in the NBCA and control groups was 92% and 96%, respectively (p = 0.6). There was one minor complication (4%, 1/26) of liver dysfunction in a patient of the NBCA group, but no complication in the control group (p = 0.26). CONCLUSION: TAE using the triaxial system with NBCA may be useful for acute arterial bleeding, especially in patients with hemorrhagic shock and coagulopathy.

Duodenal stenosis after transcatheter arterial embolization for rupture of an inferior pancreaticoduodenal aneurysm.

A 64-year-old man presented with epigastric pain and underwent contrast-enhanced computed tomography. Ruptured aneurysm of the inferior pancreaticoduodenal artery was diagnosed. TAE was successfully accomplished using coils, but vomiting appeared 9 days later. Duodenal stenosis was diagnosed from contrast-enhanced computed tomography and upper gastrointestinal endoscopy and was attributed to edematous changes in the duodenum. Conservative management led to successful recovery and discharge.

Use of microspheres in embolization for unruptured renal angiomyolipomas.

PURPOSE: To describe our initial experience with use of microspheres in transcatheter arterial embolization (TAE) for unruptured sporadic renal angiomyolipomas (AMLs). MATERIALS AND METHODS: Seven consecutive patients with seven unruptured sporadic renal AMLs, 6 females and 1 male, with a median age of 45 years (range, 30-69 years), underwent TAE using microspheres between November 2016 and February 2020. We evaluated the technical success rate, complications related to the procedure, clinical success rate, and the shrinkage rate of renal AML. Technical success was defined as the completion of TAE. Clinical success was defined as presence of shrinkage of the renal AML after TAE. RESULTS: In all patients, TAE using microspheres was accomplished and technical success rate was 100% (7/7). Three patients exhibited slight pain, but it improved with only observation, and the minor complication rate was 43% (3/7) and major complication rate was 0% (0/7). After the TAE, shrinkage of renal AML was confirmed in 6 of 7 patients, and clinical success rate was 86% (6/7). The median of shrinkage rate was 47% (range, 26-83%) with a median follow-up period of 19 months (range, 4-30 months). CONCLUSION: TAE using microspheres appears to be effective and safe for unruptured sporadic renal AMLs.

Safety and utility of performing CT-guided biopsies of pulmonary lesions that arise after radiotherapy.

This study aimed to evaluate the feasibility, safety and usefulness of performing computed tomography (CT)-guided biopsies of pulmonary lesions that arise after radiotherapy. Seventeen patients (14 males and 3 females; median age: 69 years, range: 48-84 years) underwent CT-guided biopsies of pulmonary lesions that occurred in lung regions that had previously been treated with radiotherapy. Three patients underwent CT-guided biopsies twice, and thus, the total number of procedures was 20. We reviewed the subjects' medical records and images, and evaluated the rate for obtaining pathological diagnosis with the biopsy sample, subsequent clinical course, and complications associated with the procedure. In 19 of 20 procedures (95%), the CT-guided biopsy resulted in a pathological diagnosis being obtained. In 14 procedures, the pathological results were consistent with the patients' clinical courses. In the remaining 5 procedures, the lesions were pathologically diagnosed as benign, but they increased in size thereafter; so the lesions were considered to be clinically malignant. The results were considered to represent sampling errors. There were 3 minor complications (slight pneumothorax which did not require drainage) (3/20, 15%), and there were no major complications. In conclusion, performing CT-guided biopsies of pulmonary lesions that arise after radiotherapy appears to be feasible, safe and useful.

Safety of Transcatheter Arterial Embolization for Visceral Artery Pseudoaneurysms: Incidence of Intraprocedural Rupture.

INTRODUCTION: Transcatheter arterial embolization is the first-line treatment for visceral artery pseudoaneurysms (VAPAs); however, the intraprocedural rupture of pseudoaneurysms is an important complication. The present study was performed to evaluate the safety of embolization for VAPAs, including the incidence of intraprocedural rupture. METHODS: Among 56 consecutive patients with 57 VAPAs who underwent treatment between April 2009 and October 2020, 46 patients with 47 VAPAs underwent embolization. Complications related to embolization including intraprocedural rupture, the technical success rate, and clinical outcomes were evaluated. Complications that required extended hospitalization, an advanced level of care, or resulted in permanent adverse sequelae or death were classified as major complications, while the remainder were considered to be minor. Technical success was defined as the completion of embolization. RESULTS: The intraprocedural rupture of pseudoaneurysms occurred in 3 out of 47 VAPAs treated with embolization (6%) and resulted in minor complications. One liver abscess requiring drainage was regarded as a major complication (2%). Focal infarction after embolization was observed as a minor complication in 20 cases. Complications occurred in 24 out of 47 cases (51%), comprising one major complication (2%) and 23 minor complications (48%). The technical success rate was 100% (47/47). Fifty-three out of 56 patients (95%) were alive in a median follow-up period of 18 months (range: 2 days-137 months). CONCLUSIONS: Embolization is safe and useful for the treatment of VAPAs; however, the intraprocedural rupture of pseudoaneurysms may occur, and, thus, care is needed during this procedure.

Use of 0.014-in. pushable bare platinum coils in super-selective embolization through the 1.6-Fr. microcatheter of the triaxial system.

BACKGROUND: A triple-coaxial (triaxial) system, which consists of a small microcatheter, a large microcatheter, and a 4-Fr. catheter, has been reported to allow super-selective catheterization. A 1.6-Fr. microcatheter has recently become available as the small microcatheter for the triaxial system, in addition to 0.014-in. pushable bare platinum coils that may be introduced into the 1.6-Fr. microcatheter. PURPOSE: The purpose of the present study was to evaluate the feasibility of 0.014-in. pushable bare platinum coils in embolization through the 1.6-Fr. microcatheter of the triaxial system. MATERIAL AND METHODS: Between November 2015 and October 2019, 19 embolizations were performed on 18 patients, 9 males and 9 females with a median age of 77 years (range, 41-88 years), using 0.014-in. pushable bare platinum coils through the 1.6-Fr. microcatheter of the triaxial system. The technical success rate, clinical success rate, and complications associated with the procedure were assessed. Technical success was defined as the successful delivery and placement of 0.014-in. pushable bare platinum coils, and clinical success as the immediate postembolic complete cessation of blood flow confirmed by digital subtraction angiography. RESULTS: Eighty-four 0.014-in. pushable bare platinum coils were delivered and 19 arteries were successfully embolized. The median number of 0.014-in. pushable bare platinum coils was 4 (range, 1-12). The technical success rate was 100% (84/84) and the clinical success rate was also 100% (19/19). There were no complications associated with the procedures. CONCLUSION: The use of 0.014-in. pushable bare platinum coils in super-selective embolization through the 1.6-Fr. microcatheter of the triaxial system appears to be feasible and safe.

Use of a steerable triaxial system for challenging catheterization.

Purpose: A steerable triaxial system consisting of a small microcatheter, a high-flow steerable microcatheter, and a 4-Fr. catheter is currently used in clinical settings. The purpose of the present study was to evaluate the efficacy and safety of the steerable triaxial system for challenging catheterization.Material and methods: Sixteen patients underwent an interventional procedure with the steerable triaxial system. Medical records and images of the procedures were reviewed, and the technical success rate, clinical success rate, and complications related to the procedures were evaluated. Technical success was defined as successful catheterization to the target artery using the steerable triaxial system, and clinical success as completion of the aimed procedure.Results: Catheterization to the target artery was successfully performed with the steerable triaxial system in 14 out of 16 patients, but was unsuccessful in two. Therefore, the technical success rate was 88% (14/16). The procedure was successfully accomplished in the 14 technical success patients. Thus, the clinical success rate was 88% (14/16). There were no complications related to the procedures.Conclusions: The steerable triaxial system has potential as a useful and safe technique for challenging catheterization.

Bronchial arterial embolization using a gelatin sponge for hemoptysis from pulmonary aspergilloma: comparison with other pulmonary diseases.

PURPOSE: To evaluate the clinical outcomes of bronchial artery embolization (BAE) using a gelatin sponge for hemoptysis from pulmonary aspergilloma and compare them with treatment outcomes for hemoptysis from other diseases. METHODS: Fifty-two patients underwent BAE using a gelatin sponge. The etiology of hemoptysis was pulmonary aspergilloma in 8 (PA group) and other diseases in 44 (control group). The technical success rate, clinical success rate, hemoptysis-free rate, and complication rate were compared between the PA group and control group. Technical success was defined as the complete cessation of the targeted feeding artery as confirmed by digital subtraction angiography, and clinical success as the cessation of hemoptysis within 24 h of BAE. Recurrent hemoptysis was defined as a single or multiple episodes of hemoptysis causing > 30 ml of bleeding per day. RESULTS: Technical and clinical success rates were 100% in both groups. Hemoptysis-free rates were 85% at 6 months and 72% at 12-60 months in the control group, and 38% at 6-12 months and 25% thereafter in the PA group (P = 0.0009). No complications were observed following BAE in any case in the two groups. CONCLUSION: BAE using a gelatin sponge may not be effective for hemoptysis from pulmonary aspergilloma.

Usefulness of dual-phase cone-beam computed tomography during arteriography and automated tumour-feeder detection software in transarterial embolization for obscure arterial bleeding in the abdomen.

We report the usefulness of dual-phase cone-beam computed tomography during angiography (CBCTA) and automated tumour-feeder detection software (AFD) in transarterial embolization (TAE) for three consecutive cases of obscure arterial bleeding in the abdomen. Two patients presented with lower gastrointestinal bleeding and one showed bleeding into the pancreatic pseudocyst. Superior mesenteric or common hepatic angiography did not demonstrate extravasation, but dual-phase CBCTA and AFD could identify extravasation and an access route to the bleeding point. TAE with gelatin sponge particles and a microcoil was successfully performed under AFD guidance in all patients without any complication, and haemostasis could be achieved.

Excretion of necrotic hepatocellular carcinoma tissues into the biliary system after transcatheter arterial chemoembolization.

AIM: To evaluate the incidence and condition of necrotic tumor excretion into the biliary system in patients with hepatocellular carcinoma (HCC) >5 cm treated with conventional transcatheter arterial chemoembolization (TACE). METHODS: Eighty-three patients who underwent TACE for newly developed HCC >5 cm without an intraductal tumor thrombus and were followed-up by computed tomography for longer than 6 months were eligible. According to the location, the maximum tumors were divided into central (in contact with the left or right hepatic duct, n = 39) or peripheral (not in contact with them, n = 44). When high-density material in the biliary system that was not seen on pretreatment computed tomography was identified, it was determined as excreted necrotic tumor tissue containing iodized oil. The incidence, interval between TACE and occurrence of the necrotic tumor excretion, and clinical course were evaluated. RESULTS: Tumor excretion into the biliary system was identified in nine (10.8%) patients with a central tumor (mean diameter, 85.0 ± 29.6 mm) 28-433 days (mean, 219.3 ± 128.2) after the initial TACE. In one patient, the necrotic tumor cast caused cholangitis 1203 days after the initial TACE, and was endoscopically removed. Infection of the embolized tumor developed in two cases and percutaneous drainage was carried out 105 and 158 days later, respectively. CONCLUSIONS: Excretion of necrotic tumors into the biliary system after TACE was not rare in patients with centrally located HCC >5 cm. The detached tumor rarely caused symptoms and the communication between the tumor and bile duct caused the infection of tumors.

Performance of novel virtual parenchymal perfusion software visualizing embolized areas of transcatheter arterial chemoembolization for hepatocellular carcinoma.

AIM: To evaluate the performance of novel virtual parenchymal perfusion (VPP) software in conventional transcatheter arterial chemoembolization (cTACE) for hepatocellular carcinoma. METHODS: VPP was retrospectively applied to 43 hepatocellular carcinomas treated with cTACE. The virtual embolized area (VEA) was estimated after positioning a virtual injection point on images of non-selective cone-beam computed tomography during hepatic arteriography, at the same position in superselective cTACE. The real embolized area (REA) was defined as the area where iodized oil was retained on 1-week computed tomography after cTACE. Three dimensions across the tumor (maximum [a] and minimum [b] in the axial and craniocaudal [c]) directions, and the volume of the VEA and REA were compared using linear regression analysis. It was also evaluated whether an adequate safety margin ≥5 mm could be predicted by VPP. RESULTS: The mean lengths of a, b, and c of the VEA and REA were 54.6 ± 15.9 mm (range 24.9-91.0 mm) and 55.0 ± 15.7 mm (range 23.9-92.8 mm; r = 0.9448, P < 0.001), 35.4 ± 11.7 mm (range 16.1-66.0 mm) and 35.4 ± 13.2 mm (range 12.2-69.2 mm; r = 0.9369, P < 0.001), and 42.1 ± 11.6 mm (range 25.0-75.7 mm) and 42.9 ± 11.7 mm (range 25.7-78.7 mm; r = 0.9092, P < 0.001), respectively. The mean volume of the VEA and REA was 71.8 ± 44.8 mL and 75.5 ± 46.9 mL, respectively (r = 0.9913, P < 0.0001). VPP showed no safety margins in seven tumors, including all three actually embolized without safety margins. CONCLUSION: The VEA estimated using VPP showed a good correlation with the REA of cTACE.

Preoperative transarterial embolization using gelatin sponge for hypervascular bone and soft tissue tumors in the pelvis or extremities.

BACKGROUND: Preoperative transcatheter arterial embolization for hypervascular bone and soft tissue tumors plays an important role in reducing intraoperative blood loss (IBL). PURPOSE: To evaluate the use of a gelatin sponge in preoperative transcatheter arterial embolization for hypervascular bone and soft tissue tumors in the pelvis or extremities. MATERIAL AND METHODS: Thirty-seven patients (21 men, 16 women; median age, 61 years; age range, 23-79 years) underwent preoperative transcatheter arterial embolization between April 2004 and January 2015. Medical records and images were reviewed, and the technical success rate, clinical success rate, and complications were evaluated. Technical success was defined as a devascularization rate of 75% or higher, and clinical success was defined as intraoperative blood loss (IBL) <1500 mL in cases undergoing surgery within 3 days of transarterial embolization and <3000 mL in cases operated 4 or more days later. RESULTS: Tumor sizes were in the range of 2.0-13.0 cm (median, 5.0 cm). The devascularization rate was decreased by >75% at follow-up angiography in all cases, and the technical success rate was 100 % (37/37). The median IBL was 491 mL (range, 30-3800 mL), and the clinical success rate was 89% (33/37). The minor complication of local pain was observed in 13 out of 37 cases (35%) during or after embolization, but was controllable by an analgesic. CONCLUSION: Preoperative transarterial embolization using a gelatin sponge appears to be feasible and safe, and may contribute to decreasing IBL.

Evaluation of tumor recurrence after superselective conventional transcatheter arterial chemoembolization for hepatocellular carcinoma: Comparison of computed tomography and gadoxetate disodium-enhanced magnetic resonance imaging.

AIM: To retrospectively evaluate the detectability of tumor recurrence with computed tomography (CT) and magnetic resonance imaging (MRI) after superselective conventional transcatheter arterial chemoembolization (cTACE) for hepatocellular carcinoma (HCC). METHODS: The detectability of tumor recurrence with CT and gadoxetate disodium-enhanced MRI obtained within 30 days (mean, 16.9 ± 10.1) were compared in 38 patients with recurrent HCC after superselective cTACE. Tumor recurrence was divided into local and distant recurrence. Local recurrence was also divided into intratumoral and peritumoral recurrence. RESULTS: Tumor recurrence (maximum diameter, 19.7 ± 10.1 mm) was demonstrated by images 12.4 ± 11.7 months after cTACE. CT could depict 16 (76.2%) of 21 intratumoral recurrences in 12 patients and 14 (53.8%) of 26 peritumoral recurrences in 11, as well as 39 (55.7%) of 70 distant recurrences in 15 (75%) of 20 patients. Arterial phase MRI could depict 20 (95.2%) of 21 intratumoral recurrences in 14 patients and all 26 (100%) peritumoral recurrences in 21, as well as 60 (85.7%) distant recurrences in all 20 (100%) patients. The detectability of tumor recurrence with MRI was significantly higher than that with CT (P = 0.00549). On MRI, pseudolesions were observed in five (13.2%) patients and artifacts in the arterial phase in five (13.2%). Regarding the diagnostic performance, CT was superior to MRI in two (5.3%) patients and MRI was superior to CT in 19 (50%). They were almost equal in 17 (44.7%). CONCLUSION: The detectability of tumor recurrence after superselective cTACE with gadoxetate disodium-enhanced MRI was superior to that of CT.

Efficacy of automated tumor-feeder detection software using cone-beam computed tomography technology in transarterial embolization through extrahepatic collateral vessels for malignant hepatic tumors.

AIM: We evaluated the performance of automated tumor-feeder detection (AFD) software using cone-beam computed tomography technology in identifying tumor-feeders of extrahepatic collaterals. METHODS: AFD was prospectively used in superselective transarterial chemoembolization (TACE) or embolization (TAE) of extrahepatic collaterals for 29 hepatocellular carcinomas and one liver metastasis (mean tumor diameter ± standard deviation, 28 ± 15.6 mm) in 25 patients. The detectability of extrahepatic tumor-feeders with non-selective digital subtraction angiography (DSA) and AFD was evaluated and compared using a χ(2) -test. Tumor response of target lesions in each patient at 2-3 months after treatment was evaluated using the modified Response Evaluation Criteria in Solid Tumors. Complications were also evaluated. RESULTS: Of 46 tumor-feeders, non-selective DSA and AFD could identify 26 and 44, respectively (P < 0.001). Regarding the origin of tumor-feeders, both non-selective DSA and AFD could identify 14 of 15, six of seven and two of two tumor-feeders of the right inferior phrenic, omental and right renal capsular artery, respectively. In the cystic and left gastric or right colic artery, AFD could identify 13 of 13 and nine of nine tumor-feeders but non-selective DSA could identify only three of 13 and one of nine, respectively (P < 0.001). Complete response was obtained in 15 patients, partial response in six, stable disease in three and progressive disease in one. No severe complications developed except for right pleural effusion after embolization of the right inferior phrenic artery. CONCLUSION: AFD has a sufficient ability to identify extrahepatic tumor-feeders and may improve the safety and local effects of TACE/TAE of extrahepatic collaterals.

IgG4-related disease: dataset of 235 consecutive patients.

Immunoglobulin G4-related disease (IgG4-RD) is a recently discovered systemic condition, in which various organ manifestations are linked by a similar histological appearance. Our knowledge of this condition is still fragmented, as most studies have examined only a few dozen patients or focused on a particular organ manifestation. This study was conducted to learn the demography and patient characteristics of IgG4-RD using a large cohort. A total of 235 consecutive patients with IgG4-RD, diagnosed in 8 general hospitals in the same medical district, were identified by searching the institutions' radiology database. Inclusion criteria were histology-proven IgG4-RD according to the Pathology Consensus Statement and/or definitive type 1 autoimmune pancreatitis meeting the International Consensus Diagnostic Criteria. Clinical notes and images of selected patients were retrospectively reviewed. All patients were adults (M/F = 4/1). The median age was 67 years (range 35-86). Nine tenths were diagnosed in their 50s to 70s. Among 486 manifestations identified in total, the most common was pancreatitis diagnosed in 142 patients (60%), followed by sialadenitis (34%), tubulointerstitial nephritis (23%), dacryoadenitis (23%), and periaortitis (20%). The majority of patients (95%) had at least 1 of the 5 most common manifestations. Male and female patients differed in their organ manifestations (periaortitis more common in males and sialodacryoadenitis more common in females). Serum IgG4 (normal ≤135 mg/dL) was elevated to >135 mg/dL in 208 patients (88%) and >270 mg/dL in 167 (71%). The IgG4 value was significantly higher in patients with multiorgan involvement than in those with a single manifestation (median 629 mg/dL vs 299 mg/dL, P < 0.01). Of 218 patients, for whom both IgG4 and IgG values were available, the IgG4/IgG ratio was raised to >10% in 194 (89%). Corticosteroids were effective, but the relapse rate was estimated to be 24% in the study period (median 37 months). During the follow-up, 15 malignant diseases were diagnosed in 13 patients (6%). This figure is similar to the incidence (12.9 cancers) expected from the Japanese nationwide study for cancer epidemiology (standardized incidence ratio 1.16). In conclusion, this reliable dataset could improve the characterization of IgG4-RD, particularly its unique demography and the frequency of each organ manifestation.

Light composite scalar in twelve-flavor QCD on the lattice.

On the basis of lattice simulations using highly improved staggered quarks for twelve-flavor QCD with several bare fermion masses, we observe a flavor-singlet scalar state lighter than the pion in the correlators of fermionic interpolating operators. The same state is also investigated using correlators of gluonic interpolating operators. Combined with our previous study that showed twelve-flavor QCD to be consistent with being in the conformal window, we infer that the lightness of the scalar state is due to infrared conformality. This result shed some light on the possibility of a light composite Higgs boson ("technidilaton") in walking technicolor theories.

Utility of the fluid-attenuated inversion recovery sequence in detecting a hyperintense putaminal rim in multiple system atrophy-parkinsonism: a preliminary study.

OBJECTIVE: To investigate the utility of fluid-attenuated inversion recovery (FLAIR) imaging for diagnosing multiple system atrophy-parkinsonism (MSA-P). METHODS: We retrospectively evaluated 49 subjects (19 with MSA-P including 11 with early-stage disease, 15 with Parkinson's disease and 15 matched controls) in order to compare the diagnostic value of FLAIR imaging to detect a hyperintense putaminal rim (HPR) with that of T(2)-weighted (T2W) imaging. RESULTS: Compared with T2W imaging, FLAIR imaging detected HPR more conspicuously in the 19 MSA-P patients (p = 0.01); this trend was also observed in 11 early-stage MSA-P patients (p = 0.01). Furthermore, FLAIR imaging tended to increase sensitivity of detecting HPR compared with T2W imaging (all patients: 89 vs. 58%, p = 0.07; early-stage patients: 100 vs. 55%, p = 0.06). CONCLUSIONS: FLAIR imaging might be more useful for detecting HPR in MSA-P patients, even though they are at an early stage.

Can dual-energy CT evaluate contrast enhancement of ground-glass attenuation? Phantom and preliminary clinical studies.

RATIONALE AND OBJECTIVES: Evaluation of contrast enhancement of pulmonary lesions with ground-glass attenuation (GGA) is difficult with conventional techniques but might be possible using contrast-mapping images (CMIs) obtained by dual-energy computed tomography. To address this issue, a phantom study was conducted, and this technique was then applied to clinical cases. MATERIALS AND METHODS: Phantoms made of agarose gel and those made of hollow resin clay, containing various concentrations of iodine or calcium, were used to simulate soft tissue and GGA, respectively. They were scanned using a dual-energy computed tomographic scanner, and the relationship between iodine concentration and calculated iodine value on CMIs was examined. The influence of calcium was also evaluated. In addition, contrast enhancement of 24 GGA lesions was evaluated on CMIs. RESULTS: There was a good correlation between iodine value and iodine concentration in the soft-tissue models (r(2) = 0.996). In the GGA models, the former tended to exceed the latter when default parameters for calculating CMIs were used, but this could be corrected by modifying the parameters (r(2) = 0.998). The iodine value increased with calcium concentration in both models. On CMIs, contrast enhancement was visible in 22 adenocarcinomas but not in a pulmonary hemorrhage and an inflammatory change. CONCLUSIONS: Dual-energy computed tomography can evaluate contrast enhancement of GGA lesions.