Mitsuhiro Momose

Characteristic findings in images of extra-pancreatic lesions associated with autoimmune pancreatitis.

PURPOSE Autoimmune pancreatitis is a unique form of chronic pancreatitis characterized by a variety of extra-pancreatic involvements which are frequently misdiagnosed as lesions of corresponding organs. The purpose of this study was to clarify the diagnostic imaging features of extra-pancreatic lesions associated with autoimmune pancreatitis. MATERIALS AND METHODS We retrospectively analyzed diagnostic images of 90 patients with autoimmune pancreatitis who underwent computer-assisted tomography, magnetic resonance imaging, and/or gallium-67 scintigraphy before steroid therapy was initiated. RESULTS AIP was frequently (92.2%) accompanied by a variety of extra-pancreatic lesions, including swelling of lachrymal and salivary gland lesions (47.5%), lung hilar lymphadenopathy (78.3%), a variety of lung lesions (51.2%), wall thickening of bile ducts (77.8%), peri-pancreatic or para-aortic lymphadenopathy (56.0%), retroperitoneal fibrosis (19.8%), a variety of renal lesions (14.4%), and mass lesions of the ligamentum teres (2.2%). Characteristic findings in CT and MRI included lymphadenopathies of the hilar, peri-pancreatic, and para-aortic regions; wall thickening of the bile duct; and soft tissue masses in the kidney, ureters, aorta, paravertebral region, ligamentum teres, and orbit. CONCLUSIONS Recognition of the diagnostic features in the images of various involved organs will assist in the diagnosis of autoimmune pancreatitis and in differential diagnoses between autoimmune pancreatitis-associated extra-pancreatic lesions and lesions due to other pathologies.

Differentiation of autoimmune pancreatitis from suspected pancreatic cancer by fluorine-18 fluorodeoxyglucose positron emission tomography

BackgroundFluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) has been widely used for the diagnosis of pancreatic cancer. Because autoimmune pancreatitis is easily misdiagnosed as pancreatic cancer and can be tested for by FDG-PET analysis based on the presence of suspected pancreatic cancer, we attempted to clarify the differences in FDG-PET findings between the two conditions.MethodsWe compared FDG-PET findings between 15 patients with autoimmune pancreatitis and 26 patients with pancreatic cancer. The findings were evaluated visually or semiquantitatively using the maximum standardized uptake value and the accumulation pattern of FDG.ResultsFDG uptake was found in all 15 patients with autoimmune pancreatitis, whereas it was found in 19 of 26 patients (73.1%) with pancreatic cancer. An accumulation pattern characterized by nodular shapes was significantly more frequent in pancreatic cancer, whereas a longitudinal shape indicated autoimmune pancreatitis. Heterogeneous accumulation was found in almost all cases of autoimmune pancreatitis, whereas homogeneous accumulation was found in pancreatic cancer. Significantly more cases of pancreatic cancer showed solitary localization, whereas multiple localization in the pancreas favored the presence of autoimmune pancreatitis. FDG uptake by the hilar lymph node was significantly more frequent in autoimmune pancreatitis than in pancreatic cancer, and uptake by the lachrymal gland, salivary gland, biliary duct, retroperitoneal space, and prostate were seen only in autoimmune pancreatitis.ConclusionsFDG-PET is a useful tool for differentiating autoimmune pancreatitis from suspected pancreatic cancer, if the accumulation pattern and extrapancreatic involvement are considered. IgG4 measurement and other current image tests can further confirm the diagnosis.

Hilar and Pancreatic Gallium-67 Accumulation is Characteristic Feature of Autoimmune Pancreatitis

Introduction and Aims Autoimmune pancreatitis is characterized by severe lymphocytic inflammation, suggesting that gallium-67 scintigraphy provides a useful tool for detecting characteristic lesions of this disease, because gallium-67 concentrates in lymphoid cells. We tried to determine whether gallium-67 accumulates in the characteristic lesions. Methodology We performed gallium-67 scintigraphy in 24 patients with autoimmune pancreatitis before and after 4 weeks of corticosteroid therapy and determined the factors associated with positive images. Results Sixteen patients (67%) had marked gallium-67 accumulation in the pancreas before corticosteroid therapy and negative images after 4 weeks of therapy, and they had significantly higher serum IgG4 values than did those without gallium-67 accumulation (median, 758 mg/dL versus 329 mg/dL; p = 0.011). Marked hilar gallium-67 accumulation was found in 16 patients (67%) and was also associated with significantly higher serum IgG4 values than did those without it (median, 758 versus 239 mg/dL; p = 0.0044). Among 16 patients with positive hilar images, 12 had positive pancreatic uptake and 5 had both pancreatic and salivary gland uptakes. Conclusions Hilar and pancreatic accumulation of gallium-67 is a characteristic feature of autoimmune pancreatitis during the active stage of the disease, when IgG4 serum levels are high.

Spontaneous extensive necrosis in non-Hodgkin lymphoma : Prevalence and clinical significance

Purpose We studied the prevalence of spontaneous extensive necrosis in the nodes of patients with non-Hodgkin lymphomas and assessed the clinical significance of this finding. Method CT and MRI performed before initiation of radiation or chemotherapy were reviewed in 60 consecutive patients with non-Hodgkin lymphomas to evaluate the presence or absence of spontaneous extensive necrosis in the lymphomatous nodes. The results were correlated with histopathologic grading, stages of lymphomas, maximal axial diameters of the lesions, International Prognostic Index (IPI), age, and serum lactate dehydrogenase (LDH) levels. We then performed Kaplan-Meier analysis of disease-free survival using each factor. Results Extensive necrotic nodes that appeared as rim-enhanced masses on enhanced CT or MR images were found in 15 patients (25%), of whom 10 patients had pathologic verification. The patients with necrosis had significantly higher stages (Stage II or higher), greater IPI (IPI of ≥2), and higher serum LDH levels than those without necrosis (p = 0.001, p = 0.005, and p = 0.005, respectively). With the Kaplan-Meier method, a statistically significant difference was noted for serum LDH levels (p = 0.015) and IPI (p = 0.021) but not for extensive necrosis (p = 0.600). Conclusion Spontaneous extensive necrosis in lymphomatous nodes is not a rare event. This finding may have a prognostic significance for patients with non-Hodgkin lymphomas.

MR imaging of primary malignant lymphoma in the larynx

Abstract We present MR findings in a patient with primary laryngeal lymphoma. The MR images showed a homogeneous mass in the right supraglottic larynx extending to the true vocal cord through the paraglottic space, of which signal intensity was intermediate both on T1- and T2-weighted images. The tumor was moderately enhanced and preserved mucosal layers were demonstrated as hyperintense bands on gadolinium-enhanced fat-suppressed T1-weighted images. Primary laryngeal lymphoma should be included in the differential diagnosis for a homogeneous solid mass in the supraglottic submucosal area.

Lymphoscintigraphy using technetium-99m HSA-DTPA with SPECT/CT in chylothorax after childbirth

Technetium-99m human serum albumindiethylenetriaminepentaacetic acid (HSA-DTPA) lymphoscintigraphy with single photon emission computed tomography combined with integrated low-dose computed tomography (SPECT/CT) is useful for evaluating chylothorax. We report a case of chylothorax that occurred 2 months after childbirth in a 24-year-old woman. Lymphoscintigraphy with SPECT/CT showed abnormal tracer accumulation in the right plural effusion, and chylothorax was diagnosed. Collateral branches of the thoracic duct were found to be ruptured during video-assisted thoracoscopic surgery performed for ligation.

Secondary malignant lymphoma which simulated primary thyroid cancer.

A patient with secondary thyroid lymphoma who complained of a neck mass was presented. Multiple nodules were detected in both lobes of the thyroid gland, which appeared as homogeneous hypoechoic masses on ultrasonogarphy (US), low-density masses on computed tomography (CT), and areas of increased uptake on gallium-67 scintigraphy. The residual thyroid gland was normal. Surgery established a diagnosis of secondary thyroid lymphoma with no coexistent Hashimotos thyroiditis but with cervical node involvement by lymphoma. Radiologic evidence of normal residual thyroid gland in a patient with thyroid lymphoma may be a sign of secondary thyroid lymphoma.

Semiquantitative measurement of pulmonary hilar gallium-67 uptake using single photon emission computed tomography/computed tomography for the diagnosis of autoimmune pancreatitis

PurposeWe ascertained the difference in the level of pulmonary hilar (PH) gallium-67 (Ga-67) uptake in autoimmune pancreatitis (AIP) patients between the active (before corticosteroid therapy) and remittent (after 4 weeks of corticosteroid therapy) phases using a semiquantitative measurement method based on single photon emission computed tomography (SPECT) with integrated low-dose computed tomography (CT).Materials and methodsGa-67 planar scans and SPECT were performed in 11 AIP patients before and after 4 weeks of corticosteroid therapy. A region of interest (ROI) was drawn over the bilateral pulmonary hilum and the liver, and average counts of the pulmonary hilum and liver were calculated. The average counts of the pulmonary hilum divided by those of the liver gave the pulmonary hilum/liver ratio (H/L).ResultsA significant difference was observed in the H/L between active and remittent phases. H/L in the active phase was 1.03 ± 0.32 and that in the remittent phase was 0.58 ± 0.25 (t-test, P = 0.0016).ConclusionsPH Ga-67 uptake in patients with active AIP was semiquantitatively higher than that in those with remittent AIP. Hence, this may be a useful finding for an early diagnosis, estimating the effectiveness of corticosteroid therapy, and following up patients with this disease.

Camurati-Engelmann disease on a 99mTc-HMDP bone scan.

Camurati–Engelmann disease (CED) is characterized by progressive bilaterally symmetrical diaphyseal sclerosis of the long bones [1]. The base of the skull are usually involved [2]. It is characterized by marked thickening of the cortices limited to the diaphyseal regions of tubular bones, occurring on both periosteal and endosteal surfaces [3]. It usually presents in young children with gait disturbance and limb pain and deformity [4]. Autosomal dominant transmission has been noted [5]. This case was a 56-year-old woman, with bilateral lower legs’ pain, general fatigue, and muscle weakness, who was a member of the Japanese family, with CED performed a genomewide linkage analysis in Nagasaki University School of Medicine [6]. Tc-HMDP (hydroxymethylene diphosphonate) bone scintigraphy (a) showed multi-uptakes in the bilateral upper and lower limbs, almost symmetrically extended along longitudinal bone cortices, which were consistent with sclerosing dysplasias on bone X-ray of forearms (b) and a tibia (c).

Serial assessment of left ventricular function in various patient groups with Tl-201 gated myocardial perfusion SPECT

PurposeThe present study was performed to assess stress-related left ventricular (LV) function variations in various patient groups and to determine if they were affected by sex or the type of stress experienced. We used thallium (Tl)-201 gated myocardial perfusion single-photon emission computed tomography (SPECT) for the analysis.Materials and methodsA total of 270 patients were examined by electrocardiography-gated myocardial perfusion SPECT imaging to assess LV function. After injection of Tl-201 at a dose of 111 MBq at peak stress, SPECT scans were acquired at 10 min (after stress) and 3 h (rest) after injection on a three-headed camera.ResultsIn the normal perfusion group, the mean LV ejection fraction (LVEF) was significantly higher, and both the end-diastolic volume index (EDVI) and end-systolic volume index (ESVI) were significantly lower in women than in men (P < 0.05). Poststress stunning occurred in 29 of 98 patients (30.0%) in the ischemia group and in 42 of 90 patients (46.7%) in the fixed group. There was a significant difference in poststress stunning between bicycle ergometer stress and dipyridamole stress (P < 0.05).ConclusionIn patients with normal perfusion, LVEF, EDVI, and ESVI determined by gated Tl-201 SPECT should be corrected for sex. In addition, the influence of the type of stress should be considered when assessing stress-related LV function variations.