Tsuyoshi Matsushita

Esophageal Invasion by Thyroid Carcinomas: Prediction Using Magnetic Resonance Imaging

Purpose We evaluated the accuracy of magnetic resonance imaging (MRI) in predicting esophageal invasion by thyroid carcinomas and established an optimal criterion for diagnosing esophageal invasion. Method The MRI findings (size and margins of tumor, ratio of tumor contact to the esophagus, shape and displacement of the esophagus, and tumor invasion to the outer and inner layers of the esophagus) in 67 patients with thyroid carcinomas were retrospectively reviewed and correlated with surgical and pathologic findings. Logistic modeling was used to determine the significant factors for predicting esophageal invasion. Results Seventeen (34%) of the 67 patients had pathologically or surgically verified esophageal invasion. The logistic modeling revealed that outer layer invasion (P < 0.001) and poorly defined margins (P = 0.001) were the significant factors. The outer layer invasion showed the highest accuracy of 91%, with 82% sensitivity and 94% specificity. The addition of poorly defined margins to this criterion did not improve its accuracy. Conclusion Esophageal invasion by thyroid carcinoma was accurately predicted with MRI, and an MRI finding of outer layer invasion was optimal for diagnosing esophageal invasion.

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.

Prognostic Significance of Magnetic Resonance Findings in Advanced Papillary Thyroid Cancer

We assessed the prognostic importance of magnetic resonance (MR) findings in locally advanced papillary thyroid cancer. MR findings, clinical data, and pathologic (and surgical) data for 66 patients, including 51 women and 15 men with a mean age of 57 years, who had primary surgery for papillary thyroid cancers were correlated with prognosis. Mean follow-up was 27.5 months (range, 5-117 months). Recurrence was seen in 18 patients (27%). In univariate analyses, age of 60 years or more (p = 0.0066), male gender (p = 0.0373), six MR findings (tumor size of > or = 4 cm ([p = 0.0002], ill-defined margins ([p < 0.0001], tumor extension of the trachea [p = 0.0337], carotoid artery [p = 0.0028]), esophagus [p < 0.0001], and lymph nodes [p = 0.0005]), and three pathologic findings (tumor extension of soft tissues [p = 0.0288], carotid artery [p = 0.0013], and esophagus [p < 0.0001]) had a significant adverse effect on disease-free survival. In multivariate analyses, tumor size (p = 0.0169) and nodal metastasis (p = 0.0393) determined on MR imaging and pathologic esophageal invasion (p = 0.0016) were the only significant independent variables. Esophageal invasion was accurately diagnosed with MR imaging (94% accuracy). MR findings may contain prognostic importance of locally advanced papillary thyroid cancer.

MR features of primary and secondary malignant lymphoma of the pancreas: a pictorial review

ObjectiveTo describe the imaging findings of primary and secondary pancreatic malignant lymphoma on magnetic resonance imaging (MRI), to help differentiate lymphoma of the pancreas from primary adenocarcinoma and autoimmune pancreatitis among others, and to discuss a few atypical presentations of pancreatitis mimicking lymphoma.ConclusionKnowledge of these imaging manifestations of lymphoma may be helpful to arrive at an accurate diagnosis and avoid unnecessary morbidity and mortality from inadvertent surgery.Main Messages• Pancreatic malignant lymphoma is shown as a nodular low-density area with mild enhancement on CT.• It sometimes shows variable manifestations mimicking other tumours and inflammatory conditions.• MRI provides useful information for differentiating malignant lymphoma from other mimickers.

Effect of hepatobiliary uptake of Gd-EOB-DTPA on the hepatic venous phase of dynamic magnetic resonance imaging on a 3.0-T apparatus: comparison between Gd-EOB-DTPA and Gd-DTPA.

PurposeWe aimed to reveal the difference in contrast enhancement of the abdominal organs and major vessels on dynamic contrast-enhanced magnetic resonance imaging (DCM-MRI) using gadoxetic sodium (Gd-EOB-DTPA) and gadopentetate dimeglumine (Gd-DTPA) in the same patients.Materials and methodsDCM-MRI using Gd-EOBDTPA and Gd-DTPA were performed in the same 17 patients. Precontrast and DCM-MRI images [arterial phase (AP), portal venous phase (PP), hepatic venous phase (HP)] were acquired before and after bolus injection of each contrast agent. The organ-to-muscle ratio [liver (L/M), spleen (S/M), aorta (A/M), portal vein (P/M), hepatic vein (V/M)] were calculated at each phase and analyzed statistically.ResultsThere was no significant difference between Gd-EOB-DTPA and Gd-DTPA images regarding the L/M or V/M mean on precontrast images or the mean of L/M at AP and L/M at the PP. At the AP, PP, and HP, the means of S/M, A/M, P/M, and V/M with Gd-EOBDTPA were lower than those with Gd-DTPA. On HP, The mean L/M with Gd-EOB-DTPA was higher than that with Gd-DTPA.ConclusionOn 3-T DCM-MRI using Gd-EOB-DTPA, contrast enhancement of the organs, except for the liver, was lower than that on DCM-MRI using Gd-DTPA. The HP was already affected by hepatobiliary uptake in Gd-EOB-DTPA.

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.

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.

Extraordinarily high aldosterone, 901.0 ng/dL, in a patient with primary aldosteronism: an insight into the underlying mechanism

A 43-yr-old hypertensive male was admitted due to hypokalemia (1.8 mEq/L) and renal dysfunction (eGFR, 20.0 mL/min/1.73 m2). His plasma aldosterone was 901.0 ng/dL, plasma renin activity 5.7 ng/mL/hr, and aldosterone/renin activity ratio 158. Angiotensin II (AII) was 0.7 pg/mL, ACTH <1.0 pg/mL, and cortisol 21.6 μg/dL. Liquid chromatography-tandem mass spectrometry analysis showed that aldosterone (104 times the control) as well as its precursors were significantly elevated in the patients plasma. A left adrenal (4-cm-diameter) tumor with 131I-Adosterol uptake was found and removed. Four days later, plasma aldosterone and renin activity had dropped to 7.73 ng/dL and 1.6 ng/mL/hr, respectively. However, they rose to 24.0 ng/dL and 10.9 ng/mL/hr, respectively, by Day 102. Nevertheless, magnetic resonance angiography found no evidence of a renovascular lesion. The tumor was a benign adrenocortical adenoma composed predominantly of clear cells positive for 17α-hydroxylase, [hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerases], and aldosterone synthase. A quantitative real-time polymerase chain reaction analysis of the tumor cells revealed that expression of the gene encoding aldosterone synthase was 85 times the control level. In addition, the tumor cells harbored G151R mutation of the inward rectifying potassium channel subfamily j, member 5 gene. The striking overexpression of aldosterone synthase by the tumor cells was considered the primary mechanism for the extravagant overproduction of aldosterone in this case. This overexpression may have resulted from integration of signals from AII and forced membrane depolarization due to the potassium channel mutation.