Yukihisa Saida

Double arterial phase dynamic MRI with sensitivity encoding (SENSE) for hypervascular hepatocellular carcinomas.

To investigate the efficacy of SENSE MRI, including the double arterial phase dynamic study, to detect hypervascular hepatocellular carcinomas (HCCs).

Syndromes Associated with Vascular Tumors and Malformations: A Pictorial Review

Use of the International Society for the Study of Vascular Anomalies (ISSVA) classification system has been strongly recommended in recent years because of the need for separate therapeutic measures for patients with vascular tumors and malformations. In the ISSVA classification system, vascular tumors, which are neoplastic, are distinguished from vascular malformations, which are caused by vascular structural anomalies and are not neoplastic, on the basis of the presence or absence of neoplastic proliferation of vascular endothelial cells. It is important that radiologists be familiar with the development, diagnosis, and treatment of vascular tumors and malformations, especially the imaging features of low- and high-flow vascular malformations. Some vascular tumors and malformations develop in isolation, whereas others develop within the phenotype of a syndrome. Syndromes that are associated with vascular tumors include PHACE syndrome. Syndromes that are associated with vascular malformations include Sturge-Weber, Klippel-Trénaunay, Proteus, blue rubber bleb nevus, Maffucci, and Gorham-Stout syndromes, all of which demonstrate low flow, and Rendu-Osler-Weber, Cobb, Wyburn-Mason, and Parkes Weber syndromes, all of which demonstrate high flow. Because imaging findings may help identify such syndromes as systemic, it is important that radiologists familiarize themselves with these conditions.

Focal Fatty Masses of the Pancreas

Five patients with solitary fatty mass of the pancreas examined with CT and ultrasound (US) were evaluated. The areas of fat replacement were located in the pancreatic neck, body or tail. The size ranged from 4 to 30 mm in the longest diameter. The shape varied from roundish, to ovoid to semicircular, and the contour was universally well defined. The internal structure was homogeneous in 3 patients, but in one case there were thin septa and, in another, a slightly hyperdense part in the peripheral portion. All the masses except the smallest one were in part contact with pancreatic fat. CT showed fat with the same density as the peripancreatic fat and low HU units. The mass was hypoechoic in 2 cases and hyperechoic in one. The masses in the tail of the pancreas were not detected by US.

Pitfalls in liver imaging

Abstract. Localized, abnormal attenuation/intensity areas on unenhanced and/or enhanced study of CT/MR imaging do not necessarily correspond to tumors themselves or real tumor size. Pitfalls in the diagnosis of liver tumor are described dividing into enhanced study (vascular variants, vascular abnormalities, hyperplastic nodules, around the tumor, and miscellaneous) and unenhanced study (fatty change, focal spared area of diffuse fatty liver, and miscellaneous).

Late-presenting posterior transdiaphragmatic (Bochdalek) hernia in adults: prevalence and MDCT characteristics.

Purpose The objective of our study was to determine the prevalence of posterior transdiaphragmatic hernia in a large normal adult population. We also performed volume measurements and described its characteristics and sequential changes. Materials and Methods We prospectively evaluated 3107 chest computed tomography screenings obtained at our center between September 2005 and March 2006. The images were analyzed by experienced radiologists, who focused on the distribution, size, content, and sequential changes of the diaphragmatic hernia. Volumetric measurement was used to evaluate the size of the hernia. We also performed a chart review for each case and recorded the sex, age, symptoms, and clinical history. Results A total of 525 hernias were identified in 396 of 3107 persons, representing an incidence of 12.7%. Age ranges were 36 to 86 years and average was 62.8 years. The prevalence of the posterior diaphragmatic hernias in the 50s, 60s, and 70s age groups was 10.5% (168/1596), 13.7% (137/1003), and 20.3% (80/394), respectively. All persons were asymptomatic. In 93.7% (492/525) of the hernias, only fat was observed, whereas kidney involvement was observed in 5.5% (29/525). Protruded hernia content extended along the diaphragm, thoracoabdominal wall, and in the intermediate position between these 2 structures in 53.7%, 32.8%, and 13.5% of the hernias, respectively. No significant sequential changes were observed (P=0.082) during our follow-up period (12 to 27 mo). Conclusions Incidentally observed posterior transdiaphragmatic hernias are a common finding on multidetector-row computed tomography, occurring in up to 20% of persons by age 70 years.

Systemic arterial supply to the normal basal segments of the left lower lobe treated by coil embolization, with long-term follow-up

We report a case of a 41-year-old woman who underwent therapeutic embolization of an aberrant systemic artery of the lung. Except for chest pains immediately after embolization, she recovered well and has not experienced hemoptysis in the past 6 years. In such patients, coil embolization could be an alternative choice of treatment, with the expectation of an excellent long-term result despite ischemia of the corresponding lung parenchyma.

Hyperattenuating rim on noncontrast CT of the liver: Probable peritumoral sparing of fatty infiltration

CT scans showing a hyperattenuating rim within the liver were retrospectively evaluated in 10 patients to clarify the character, aetiology and clinical significance. All patients had hepatic tumours (7 cavernous haemangiomas in 6 patients, 3 metastatic tumours and 1 hepatocellular carcinoma) as well as fatty infiltration of the liver. Typical features of the hyperattenuating rim on noncontrast CT of the liver included (1) attenuation similar to that of the spleen, (2) a circular or semicircular shape, (3) a width of a few millimeters, (4) peritumoral localization and (5) loss of visualization with contrast enhancement. No such rims were noted around hepatic tumours unassociated with fatty infiltration. Peritumoral sparing of fatty infiltration was inferred. A hyperattenuating rim on noncontrast liver CT, although rare, suggests the presence of a hepatic tumour in fatty liver.

CT and MRI in detection of intrahepatic portosystemic shunts in patients with liver cirrhosis.

Objective Our goal was to determine the prevalence and anatomic location of intrahepatic portosystemic shunts (IPSs) in patients with hepatic cirrhosis as shown by CT and MRI. Materials and Methods We retrospectively reviewed CT and MR scans of 33 cirrhotic patients who had IPSs. In addition, two series of 100 consecutive CT or MR were reviewed to determine the prevalence of IPSs and the percentage of intrahepatic and extrahepatic paraumbilical veins. Results Intrahepatic portosystemic shunts were divided into three groups according to the intrahepatic course: paraumbilical shunt between the left portal vein and the paraumbilical vein anterior to the liver (n = 29); inferior vena caval shunt between the posterior branch of the right portal vein and the inferior vena cava (n = 2); and miscellaneous (n = 2). Shunts of the paraumbilical type ran through the medial (n = 23), lateral (n = 3), or both medial and lateral (n = 3) segments of the left lobe of the liver. Twenty-five patients had one shunt, and four had more than one. Six cases were also associated with extrahepatic paraumbilical veins. Conclusion Intrahepatic portosystemic shunts, especially the paraumbilical type, were not infrequently visualized in patients with hepatic cirrhosis.

Quantification of Fatty Degeneration Within the Supraspinatus Muscle by Using a 2-Point Dixon Method on 3-T MRI

OBJECTIVE The objective of this study was to quantify fatty degeneration of the supraspinatus muscle by using a 2-point Dixon technique on 3-T MRI and to evaluate the correlation of muscular atrophy and fat fraction values among different severities of rotator cuff tears across differing ages and sexes. SUBJECTS AND METHODS Patients with shoulder pain (n = 359) were evaluated by shoulder MRI on a 3-T unit, including a 2-point Dixon sequence for quantification of muscle atrophy and fatty degeneration within the supraspinatus muscle. Two board-certified musculoskeletal radiologists evaluated the degree of rotator cuff tears in three groups: full-thickness tear (n = 63), partial tear (n = 54), and no tear (n = 242). In quantitative analysis, we measured signal intensity values of in-phase images (SIn) and fat images (SFat) within the supraspinatus muscle, and the fat fraction was calculated as SFat/SIn. The Thomazeau occupation ratio was used as a quantitative index of muscular atrophy. Fat fraction and muscle atrophy were evaluated among these groups. RESULTS Fat fraction values were changed with the degree of rotator cuff tears and were (mean ± SD) 0.258 ± 0.123 among patients with full-thickness tears, 0.166 ± 0.067 among patients with partial tears, and 0.128 ± 0.061 among patients with no tears, with statistically significant differences (p < 0.001). The values were higher in female than in male patients in all groups. The Pearson correlation coefficient was 0.348 between age and fat fraction value, and 0.664 between muscular atrophy rate and fat fraction value. CONCLUSION An increase in supraspinatus fatty degeneration was statistically significantly correlated with severity of supraspinatus tears and moderately correlated with muscular atrophy. Fatty degeneration tends to progress more rapidly than muscular atrophy in female patients, with statistically significant sex differences.

Thoracolithiasis: 11 cases with a calcified intrapleural loose body.

Purpose To describe clinical and imaging characteristics of thoracolithiasis. Materials and Methods Medical records from our center from September 2005 to March 2007 were reviewed. A definitive diagnosis was made by multidetector-row computed tomography studies of the chest, which revealed in each patient an intrapleural calcified nodular opacity, which changed in intrapleural location on serial examinations. Eleven patients fulfilled this criteria. The images were analyzed by experienced radiologists, who focused on the distribution, size, and shape of the thoracolithiasis. Results The incidence of thoracolithiasis was 0.086% (11 of 12,835 individuals). All the patients were asymptomatic and did not have any history of intrathoracic disease. The nodules ranged in size from 5 to 15 mm (median 8 mm), and were ovoid and smoothly marginated. Each nodule contained homogeneous diffuse calcification. Eight nodules occurred in the left pleural space and 3 in the right. Their locations varied, which included on the diaphragm, along the posterior chest wall of the lower lung, abutting the left cardiac margin, and near the paraspinal space of the lower thoracic spine. Each of the calcified pleural bodies changed in intrapleural location on follow-up computed tomography examination. Conclusions The calcified intrapleural nodular opacities of thoracolithiasis tended to be located inferiorly, presumably secondary to the effects of gravity, and they seemed to migrate freely within the pleural cavity.