Shunro Matsumoto

Thoracic manifestation of myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA)-related disease. CT findings in 51 patients.

Objective To assess the pulmonary CT findings of patients with serum evidence of the myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA). Methods The pulmonary CT scans of 62 patients with serum evidence of MPO-ANCA (51 with microscopic polyangiitis, 11 with Churg-Strauss syndrome) were retrospectively assessed with regard to parenchymal, pleural, and mediastinal abnormalities. Results On the CT scans, abnormal findings were seen in 51 of the patients (82%, n = 62). Of the patients, the CT findings consisted of ground-glass attenuation in 48 of the patients (94%, n = 51), consolidation in 40 (78%), and thickening of bronchovascular bundles in 26 (51%). Pathologically, these findings corresponded to alveolar hemorrhages, interstitial chronic inflammation in the alveolar septa, vasculitis, or fibrosis. These abnormalities were predominantly seen in peripheral lung parenchyma (n = 37). Conclusion The CT findings in patients with MPO-ANCA consisted mainly of ground-glass attenuation and consolidation in the peripheral lung. These findings, although nonspecific, are considered as pulmonary involvement in patients with MPO-ANCA.

CT and MR imaging findings of xanthogranulomatous cholecystitis: correlation with pathologic findings

The aim of this study was to evaluate CT and MRI findings in xanthogranulomatous cholecystitis (XGC) and to correlate the imaging findings with various pathologic parameters. The study included 13 patients with histopathologically confirmed XGC. The CT (n=13) and MRI (n=5) obtained in these patients were evaluated retrospectively. On CT, low-attenuation areas in the wall of XGC correlated with foam and inflammatory cells or necrosis and/or abscess in XGC. Areas of iso- to slightly high signal intensity on T2-weighted images, showing slight enhancement at early phase and strong enhancement at last phase on dynamic study, corresponded with areas of abundant xanthogranulomas. Areas with very high signal intensity on T2-weighted images without enhancement corresponded with necrosis and/or abscesses. Luminal surface enhancement (LSE) of gallbladder wall represented preservation of the epithelial layer. The early-enhanced areas of the liver bed on dynamic CT and MR images corresponded with accumulation of inflammatory cells and abundant fibrosis. Our results indicate that CT and MRI findings correlate well with the histopathologic findings of XGC.

Chlamydia pneumoniae pneumonia and Mycoplasma pneumoniae pneumonia: comparison of clinical findings and CT findings.

The objective of this study was to identify the clinical and pulmonary CT findings associated with Chlamydia pneumoniae pneumonia and to compare them with those of Mycoplasma pneumoniae pneumonia. The clinical features and CT scans of 40 patients with C. pneumoniae pneumonia and 42 patients with M. pneumoniae pneumonia were retrospectively reviewed. There were no significant differences between the two etiologic agents with regard to clinical signs. Chest CT findings in patients with C. pneumoniae pneumonia consisted mainly of ground-glass attenuation (n = 38) and acinar patterns (n = 28). Acinar patterns and pleural effusions (n = 12) were observed significantly more frequently than in patients with M. pneumoniae pneumonia (P < 0.0001, P < 0.039, respectively). CT findings of centrilobular nodules and bronchial wall thickening were significantly less common than in the M. pneumoniae pneumonia patients (P < 0.0001, P < 0.0001, respectively). The CT finding of acinar patterns, although nonspecific, can be considered suggestive of C. pneumoniae pneumonia.

Primary malignant lymphoma of the gallbladder: a case report and literature review

Primary malignant lymphoma of the gallbladder is extremely rare and the associated radiological findings are not well described in the literature. We report a case of malignant lymphoma in the gallbladder wall of a 78-year-old woman. Pre-operative CT and MRI showed homogeneous submucosal thickening of the gallbladder wall with a preserved mucosal surface. These unique radiological findings may be useful for diagnosing malignant lymphoma of the gallbladder.

Ethanol injection therapy of an isolated bile duct associated with a biliary‐cutaneous fistula

Abstract  Bile leakage after hepatic resection often results in the formation of a biliary‐cutaneous fistula. Such a fistula, when caused by an isolated bile duct in the remnant liver, can be intractable. We report a successful case of ethanol injection therapy of an isolated bile duct. A 73‐year‐old man underwent right hepatic resection for hepatocellular carcinoma. Bile leakage occurred after surgery, and the patient developed a biliary‐cutaneous fistula. Fistulography revealed an isolated bile duct in the remnant portion of the caudate lobe without communication to the main biliary system. As conservative management with simple drainage was ineffective, injection therapy with ethanol was performed with a balloon occlusion catheter. After 11 therapy sessions, the bile duct was eradicated, and the biliary‐ cutaneous fistula was completely healed. The post‐treatment course was uneventful. Ethanol injection therapy can be a choice for management of patients with a biliary fistula caused by an isolated bile duct.

MRI signal characteristics of progressive massive fibrosis in silicosis

AIM To determine the magnetic resonance imaging (MRI) signal characteristics of progressive massive fibrosis (PMF) in silicosis. SUBJECTS AND METHODS We evaluated prospectively the MR appearances in 17 patients with 34 PMF lesions on the basis of pre-contrast signal intensity (SI) and SI pattern and post-contrast enhancement pattern, using a 0.5-T unit. There were 13 PMF lesions in six patients who had silicosis and 21 PMF lesions in 11 patients who had silicotuberculosis. The SI pattern on T2-weighted image (WI) was classified into four types and the pattern of contrast enhancement on T1-WI was classified into three types. MR appearances of PMF lesions were correlated with the findings of computed tomography (CT). RESULTS The commonest signal intensity characteristic was isointensity (70%) on T1-WI and hypointensity (68%) on T2-WI when compared with skeletal muscle. For signal pattern on T2-WI, a type with only internal high SI areas (46% in silicosis group, 38% in silicotuberculosis group) was most frequent. All of these areas corresponded to the low density areas at CT, suggestive of necrosis. After intravenous contrast medium enhancement, rim enhancement (54% in silicosis group, 52% in silicotuberculosis group) was most frequent, followed by no enhancement. CONCLUSION The most common MRI appearance of PMF was isointensity on T1-WI and hypointensity on T2-WI when compared with skeletal muscle, with internal high SI areas on T2-WI and either rim enhancement or no enhancement.

Extrapancreatic neural plexus invasion by carcinomas of the pancreatic head region: evaluation using thin-section helical CT

PurposeThe aim of this study was to determine the computed tomographic (CT) criteria for diagnosing the second portion of the extrapancreatic neural plexus (PLX-II) invasion by carcinoma of the pancreatic head region on thin-section helical CT.Materials and methodsA total of 41 patients with carcinoma of the pancreatic head region (17 in the pancreas, 24 in the lower common bile duct) underwent three-phase helical CT (collimation 5 mm; reconstruction 2.5 mm) before surgery. Two criteria were established for the assessment of the PLX-II running between the superior mesenteric artery (SMA) and the medial margin of the uncinate process: criterion A: assessment of the area around the SMA and inferior pancreaticoduodenal artery; criterion B: assessment of the jejunal trunk.ResultsPLX-II invasion was pathologically confirmed in 19 patients with pancreatobiliary carcinoma. For criterion A, all 19 patients with positive PLX-II invasion and 20 of the 22 with negative PLX-II invasion were correctly diagnosed (sensitivity 100%; specificity 91%; accuracy 95%). For criterion B, 3 of the 17 patients with positive PLX-II invasion and all 20 with negative PLX-II invasion were correctly diagnosed (sensitivity 18%; specificity 100%; accuracy 62%). The two false-positive cases using criterion A were correctly diagnosed using criterion B.ConclusionThin-section helical CT provides sufficient diagnostic ability regarding PLX-II invasion by carcinoma of the pancreatic head region.

Diagnosis of lung cancer in a patient with pneumoconiosis and progressive massive fibrosis using MRI

Abstract. We report the MRI features and correlative pathologic findings of a lung cancer in a patient with progressive massive fibrosis (PMF). In this case, MRI was able to distinguish the lung cancer as a high signal intensity area, and the fibrotic mass as a low signal intensity area, on both T1-weighted and T2-weighted images when compared with muscle. MRI is potentially useful in distinguishing cancer tissue from PMF in patients with pneumoconiosis.

Adrenal nonhyperfunctioning adenoma and nonadenoma: CT attenuation value as discriminative index.

BackgroundWhen an asymptomatic adrenal mass is incidentally discovered on abdominal CT scans, the distinction between a nonhyperfunctioning adenoma and a nonadenoma would be important.MethodsWe evaluated the CT findings of 36 adrenal masses (14 nonhyperfunctioning adenomas, 22 nonadenomas) in 34 patients with no evidence of hormonal hypersecretion. CT attenuation values of adrenal masses on CT scans were calculated by setting a circular region of interest as large as possible in the center of each adrenal mass.ResultsBelow 20 HU in CT attenuation values, all adrenal masses, except one case of ganglioneuroma with myxomatous change, were nonhyperfunctioning adenomas. With an arbitrary threshold of 20 HU, the sensitivity of CT attenuation values in distinguishing nonhyperfunctioning adenomas from nonadenomas was 64%, the specificity was 95%, and the accuracy was 83%. When decreasing the threshold to 15 HU, the sensitivity was 64%, the specificity was 100%, and the accuracy was 86%. The CT attenuation value on noncontrast CT was more useful for making this distinction than the size and interior homogeneity.ConclusionsOur data suggest that an asymptomatic adrenal mass with homogeneous low attenuation (≦15 HU) and less than or equal to 4 cm indicates a nonhyperfunctioning adenoma, and no further examinations are necessary. CT attenuation value on non-contrast CT is the most important discriminatory factor.

Invasive carcinomas derived from intraductal papillary mucinous neoplasms of the pancreas: a long-term follow-up assessment with CT imaging.

Objective: To describe computed tomography (CT) findings of invasive carcinoma derived from intraductal papillary mucinous neoplasms (IPMNs) of the pancreas during long-term follow-up. Methods: Follow-up CT findings of 5 patients with IPMNs progressing to invasive carcinomas were respectively reviewed for 12 to 63 months. All patients underwent thin-section 3-phase helical and/or multislice CT. Results: Invasive carcinomas were detected as hypo- (n = 3) or hyperattenuating (n = 2) solid masses in the pancreatic parenchyma on contrast-enhanced CT. Hypoattenuating masses were mostly visualized on arterial dominant phase images. In 4 branch-duct type IPMNs, the solid masses appeared with (n = 3) or without (n = 1) dilatation of the main pancreatic duct after 3 to 5 years. In the remaining combined-type IPMN, a solid mass was detected on initial CT and progressively increased during the follow-up. Conclusions: Arterial dominant phase CT is useful for detecting invasive carcinoma derived from IPMNs and is an effective follow-up method.