Toshihiro Furuta

Hepatic Segments and Vasculature: Projecting CT Anatomy onto Angiograms.

Hepatic transarterial interventional therapies such as chemoembolization and radiation embolization are important treatment options for hepatocellular carcinoma. Understanding the anatomy of individual arterial branches and hepatic segments is critical for selecting the correct embolization technique for treatment and to avoid complications. The authors describe the morphologic characteristics of hepatic arterial branches (and their mimickers) and hepatic segments on conventional angiograms. These vessels and segments include the celiac artery, the common and proper hepatic arteries, the left and right hepatic arteries and branches, the caudate lobe, and the portal vein and branches. Mimickers of hepatic arteries include the cystic, accessory left gastric, and right gastric arteries, as well as branches of the left gastric artery that resemble segmental branches of the replaced left hepatic artery. The authors describe how each segmental branch of the hepatic artery and the area it supplies correlates at computed tomography (CT) and angiography. Finally, the authors demonstrate how the vascular anatomy changes with the respiratory cycle by creating a virtual movie from calculations with dynamic CT data, in which the arterial and venous phases are acquired at end expiration and inspiration, respectively. Each segmental branch of the hepatic artery has morphologic characteristics that help distinguish it from mimickers. The location of each hepatic segment can be estimated if the artery supplying the segment can be correctly identified on angiograms. Notably, morphologic differences in the hepatic artery system caused by respiration should be recognized.Hepatic transarterial interventional therapies such as chemoembolization and radiation embolization are important treatment options for hepatocellular carcinoma. Understanding the anatomy of individual arterial branches and hepatic segments is critical for selecting the correct embolization technique for treatment and to avoid complications. The authors describe the morphologic characteristics of hepatic arterial branches (and their mimickers) and hepatic segments on conventional angiograms. These vessels and segments include the celiac artery, the common and proper hepatic arteries, the left and right hepatic arteries and branches, the caudate lobe, and the portal vein and branches. Mimickers of hepatic arteries include the cystic, accessory left gastric, and right gastric arteries, as well as branches of the left gastric artery that resemble segmental branches of the replaced left hepatic artery. The authors describe how each segmental branch of the hepatic artery and the area it supplies correlates at computed tomography (CT) and angiography. Finally, the authors demonstrate how the vascular anatomy changes with the respiratory cycle by creating a virtual movie from calculations with dynamic CT data, in which the arterial and venous phases are acquired at end expiration and inspiration, respectively. Each segmental branch of the hepatic artery has morphologic characteristics that help distinguish it from mimickers. The location of each hepatic segment can be estimated if the artery supplying the segment can be correctly identified on angiograms. Notably, morphologic differences in the hepatic artery system caused by respiration should be recognized.

Artifact‐reduced simultaneous MRI of multiple rats with liver cancer using PROPELLER

To explore simultaneous magnetic resonance imaging (MRI) for multiple hepatoma‐bearing rats in a single session suppressing motion‐ and flow‐related artifacts to conduct preclinical cancer research efficiently.

Hemosuccus Pancreaticus in a Patient with Iodine Allergy: Successful Diagnosis with Magnetic Resonance Imaging and Treatment with Transarterial Embolization Using Carbon Dioxide as the Contrast Medium

Hemosuccus pancreaticus (HP) is defined as gastrointestinal bleeding via the pancreatic duct and duodenal papilla. Since the bleeding is usually intermittent, it often remains undetected by endoscopy. Most cases are diagnosed by contrast-enhanced computed tomography (CT) or angiography, and the first-line treatment is transarterial embolization (TAE). However, in general, these modalities require a large amount of iodinated contrast medium. Here, we report the case of a 50-year-old female with HP due to chronic pancreatitis. Contrast-enhanced CT and ordinary angiography were contraindicated for her, as she was allergic to iodine. She was diagnosed with HP following gadolinium-enhanced magnetic resonance imaging and successfully treated by TAE of the splenic artery with metallic coils using carbon dioxide as the contrast medium.

Erdheim–Chester disease with an 18F-fluorodeoxyglucose-avid breast mass and BRAF V600E mutation

Abstract Erdheim–Chester disease (ECD) is a non-Langerhans cell histiocytosis. Herein we report a case of a 49-year-old woman who developed bilateral knee pain. Imaging procedures revealed multiple long bone lesions and a well-defined 18F-fluorodeoxyglucose-avid mass in the left breast. The breast mass was resected, and an open biopsy was performed on the right femoral lesion. Both specimens revealed involvement by histiocytic infiltrates with features suggestive of ECD. The BRAF V600E mutation was detected by DNA sequencing and immunohistochemistry.

Magnetic resonance microscopy imaging of posterior interosseous nerve palsy

Posterior interosseous nerve palsy, also called deep radial nerve syndrome, is a neuropathy caused by radial nerve entrapment or compression at the level of the supinator muscle. Although imaging studies are not necessary for diagnosing this syndrome because of its characteristic clinical manifestations, the causes of palsy, which include mass lesions, or precise anatomical findings can sometimes be demonstrated by imaging. Magnetic resonance (MR) findings of posterior interosseous nerve palsy have been described as involving atrophy of related muscles caused by denervation, a common secondary change of this nerve disorder. We present a case in which the swollen posterior interosseous nerve itself could be directly depicted by MR imaging using a 4.7-cm microscopy coil in a patient with neuropathy.

Detection of Lung Tumors in Mice Using a 1-Tesla Compact Magnetic Resonance Imaging System

Due to their small size, lung tumors in rodents are typically investigated using high-field magnetic resonance (MR) systems (4.7 T or higher) to achieve higher signal-to-noise ratios, although low-field MR systems are less sensitive to susceptibility artifacts caused by air in the lung. We investigated the feasibility of detecting lung tumors in living, freely breathing mice with a 1-T compact permanent magnet MR system. In total, 4 mice were used, and MR images of mouse lungs were acquired using a T1-weighted three-dimensional fast low-angle shot sequence without cardiac or respiratory gating. The delineation and size of lung tumors were assessed and compared with histopathological findings. Submillimeter lesions were demonstrated as hyperintense, relative to the surrounding lung parenchyma, and were delineated clearly. Among the 13 lesions validated in histopathological sections, 11 were detected in MR images; the MR detection rate was thus 84.6%. A strong correlation was obtained in size measurements between MR images and histological sections. Thus, a dedicated low-field MR system can be used to detect lung tumors in living mice noninvasively without gating.

Full and hybrid iterative reconstruction to reduce artifacts in abdominal CT for patients scanned without arm elevation

Background Abdominal computed tomography (CT) without arm elevation is associated with degraded image quality due to streak artifacts. Purpose To compare the degree of streak artifacts in abdominal CT images without arm elevation between full iterative reconstruction (IR), hybrid IR, and filtered back projection (FBP) using two commercially available scanners. Material and Methods First, a phantom study simulating CT examination without arm elevation was performed. Second, unenhanced axial images of 33 patients (17 and 16 patients for each vendor) who underwent CT without arm elevation were reconstructed with full IR, hybrid IR and FBP. A radiologist placed 50 parallel lines with lengths of 50 pixels vertical to the streaks and quantitatively evaluated the images for streak artifacts in the phantom study. Two radiologists evaluated the images of patients for streak artifacts (on the liver and the kidney) and diagnostic acceptability using a four-point scale. Results The phantom study indicated that full IR algorithms were more effective than FBP in reducing streak artifacts. In the clinical patient study, streak artifacts were significantly more reduced with full IR compared with FBP in both the liver and kidney (P < 0.012). Streak artifact reduction was limited with hybrid IR. Model-based iterative reconstruction (MBIR) (one of the full IR algorithms) provided diagnostically more acceptable image quality (P < 0.016) compared with FBP. Conclusion In abdominal CT without arm elevation, full IR enabled a more efficient streak artifact reduction compared with FBP and MBIR was associated with diagnostically more acceptable images.

Magnetic resonance-based visualization of thermal ablative margins around hepatic tumors by means of systemic ferucarbotran administration before radiofrequency ablation: animal study to reveal the connection between excess iron deposition and T2*-weighted hypointensity in ablative margins.

Objective The objective of this study was to demonstrate experimentally that radiofrequency ablation (RFA) of ferucarbotran-accumulated healthy liver tissues causes excess iron deposition in the ablated liver tissues on postablation days and produces sustained T2*-weighted low signals indicative of ablative margins surrounding hepatic tumors. Materials and Methods We conducted 3 experiments using 30 rats. In experiment 1, we administered either ferucarbotran (n = 6) or saline (n = 4), acquired T2*-weighted images (T2*-WIs) of the liver by using a 3-T magnetic resonance scanner, and subsequently performed RFA of healthy liver lobes. We acquired follow-up T2*-WIs up to day 7 and histologically analyzed the liver specimens. In another 4 rats, we performed sham operation, instead of RFA, in ferucarbotran-accumulated liver lobes, followed by the same image acquisition and histological analysis. In experiment 2, we administered 59Fe-labeled ferucarbotran, subsequently performed either RFA (n = 4) or sham operation (n = 4) in the liver, and acquired autoradiograms of the liver specimens on day 7. In experiment 3, we conducted RFA treatment for 8 rats bearing orthotopic hepatic tumors after ferucarbotran administration and monitored tumor growth by using serial T2*-WIs. Results On days 4 and 7 of the experiment 1, T2*-WIs of 6 rats with systemic ferucarbotran administration and subsequent hepatic RFA showed low-signal regions indicative of ablated liver tissues, whereas high-signal areas were seen in 4 saline-administered rats. Neither high nor low signal areas were detected in 4 sham-operated rats. Histologically, larger amounts of iron were observed in the RFA-induced necrotic liver tissues in the ferucarbotran-administered rats than in the saline-administered-rats. The 59Fe autoradiography of the rats in experiment 2 revealed accumulation of ferucarbotran-derived iron in necrotic liver tissues. Among 6 hepatic tumors grown in 6 rats of the experiment 3, a total of 4 tumors were stable in size, but the other 2 increased markedly on day 7. Retrospectively, T2*-WIs showed the former tumor sites surrounded completely by low-signal areas on day 4. Conclusions The RFA of ferucarbotran-accumulated healthy liver tissues in the rats caused excess iron deposition in the ablated liver tissues and produced sustained T2*-weighted hypointense regions. Similar hypointense regions surrounding hepatic tumors were indicative of ablative margins.

Single-energy metal artifact reduction technique for reducing metallic coil artifacts on post-interventional cerebral CT and CT angiography

PurposeTo evaluate the effects of the single-energy metal artifact reduction (SEMAR) algorithm on image quality of cerebral CT and CT angiography (CTA) for patients who underwent intracranial aneurysm coiling.MethodsTwenty patients underwent cerebral CT and CTA using a 320-detector row CT after intracranial aneurysm coiling. Images with and without application of the SEMAR algorithm (SEMAR CT and standard CT images, respectively) were reconstructed for each patient. The images were qualitatively assessed by two independent radiologists in a blinded manner for the depiction of anatomical structures around the coil, delineation of the arteries around the coil, and the depiction of the status of coiled aneurysms. Artifact strength was quantitatively assessed by measuring the standard deviation of attenuation values around the coil.ResultsThe strength of artifacts measured in SEMAR CT images was significantly lower than that in standard CT images (25.7 ± 10.2 H.U. vs. 80.4 ± 67.2 H.U., p < 0.01, Student’s paired t test). SEMAR CT images were significantly improved compared with standard CT images in the depiction of anatomical structures around the coil (p < 0.01, the sign test), delineation of the arteries around the coil (p < 0.01), and the depiction of the status of coiled aneurysms (p < 0.01).ConclusionThe SEMAR algorithm significantly reduces metal artifacts from intracranial aneurysm coiling and improves visualization of anatomical structures and arteries around the coil, and depiction of the status of coiled aneurysms on post-interventional cerebral CT.

Persistent T2*-hypointensity of the liver parenchyma after irradiation to the SPIO-accumulated liver: An imaging marker for responses to radiotherapy in hepatic malignancies.

To determine whether T2*‐weighted MRI has the ability to visualize the irradiated liver parenchyma and liver tumor after irradiation to the previously superparamagnetic iron oxide (SPIO)‐accumulated liver.