Masayuki Nakajo

Clinical Evaluation of Tumor Imaging with 201TI Chloride1

201TI was used as an imaging agent in 173 malignant tumors and 76 benign lesions. The sensitivity, specificity, and accuracy were 0.64, 0.61, and 0.63, respectively. Sensitivity was good in thyroid cancer (0.91) and fair in primary lung cancer (0.70) and primary liver cancer (0.71). Compared with 67Ga, 201TI appears to have a higher sensitivity in thyroid cancer and nearly the same sensitivity in primary lung cancer. 201TI might be useful in distinguishing cold thyroid nodules and in differentiating primary liver cancer from metastases.

Pancreatic Adenocarcinoma: Variability of Diffusion-weighted MR Imaging Findings

PURPOSEnTo compare the apparent diffusion coefficients (ADCs) of pancreatic adenocarcinomas that appear hyperintense with clearly defined borders (clear hyperintense) with those that do not show clear hyperintense borders on diffusion-weighted magnetic resonance (MR) images.nnnMATERIALS AND METHODSnInstitutional review board approval was obtained and informed consent was waived. Eighty patients with histologically confirmed pancreatic adenocarcinoma (mean tumor size, 32 mm) underwent fat-suppressed single-shot echo-planar 3.0-T diffusion-weighted MR imaging with diffusion gradients (b = 1000 sec/mm(2)). ADC values of the pancreatic adenocarcinomas (n = 80) and proximal (n = 51) and distal (n = 70) pancreas were compared by using the Friedman test, followed by the Wilcoxon signed-rank test, and the difference in serum amylase levels between pancreatic adenocarcinomas with and without clear hyperintensity was evaluated by using the x(2) test.nnnRESULTSnIn 38 of 80 patients, pancreatic adenocarcinomas showed clear hyperintensity relative to the surrounding pancreas; 26 were hyperintense with unclear distal borders; 12, isointense; and four, hypointense. In all patients, the mean ADC (± standard deviation) of the tumors (1.16 × 10(-3) mm(2)/sec ± 0.22) was significantly lower than those of the proximal pancreas (1.33 × 10(-3) mm(2)/sec ± 0.16, P < .001) and the distal pancreatic parenchyma (1.24 × 10(-3) mm(2)/sec ± 0.23, P = .004). No significant difference in ADC was seen between the pancreatic adenocarcinomas without clear hyperintensity and the distal pancreas. The frequency of serum amylase levels greater than 120 U/L (2.00 μkat/L) was significantly higher than in those with clear hyperintense pancreatic adenocarcinomas (P < .001).nnnCONCLUSIONnDiffusion-weighted MR imaging was not useful for delineating 47% of pancreatic adenocarcinomas, because of hyperintensity of the pancreatic parenchyma distal to the cancer.

FDG PET/CT and diffusion-weighted imaging of head and neck squamous cell carcinoma: comparison of prognostic significance between primary tumor standardized uptake value and apparent diffusion coefficient.

Purpose: To compare primary tumor 18F-fluorodeoxyglucose (FDG) maximum standardized uptake value (SUVmax) and diffusion-weighted imaging (DWI) apparent diffusion coefficient (ADC) obtained in the same patients with head and neck squamous cell carcinoma (HNSCC) to clarify the prognostic significance of both indexes. Materials and Methods: The study population comprised 26 patients with HNSCC visible on both pretreatment FDG PET/CT and DWI. Correlation between SUVmax and ADC (b values; 0 and 800 seconds/mm2) was analyzed by the Spearmans rank test. Disease-free survival (DFS) was calculated by the Kaplan-Meier method. Prognostic significance was assessed by the long-rank test and Cox proportional hazards analysis. Results: SUVmax and ADC correlated significantly and negatively (&rgr; = −0.566, P = 0.005). High (>12.1) SUVmax (P < 0.001), low (⩽0.88) ADC (P = 0.009), high (T3–4) T stage (P = 0.030), and high (N2–3) N stage (P = 0.007) were significant in predicting poor 2-year DFS. The accuracy for predicting disease events was 81% (21/26) for SUVmax (>12.1) and 73% (19/26) for ADC(⩽0.88) without significant difference between them (P = 0.52). Disease event hazards ratios for significant unadjusted SUVmax (P = 0.015) and ADC (P = 0.039) remained significant when adjusted for other dichotomized clinical covariates (SUVmax; P = 0.009–0.039, ADC; P = 0.017–0.037) except SUVmax for ADC and ADC for SUVmax and T stage. Conclusion: These results suggest that pretreatment primary tumor SUVmax and ADC correlate significantly and negatively and both may have similar potential to predict DFS or disease events of HNSCC.

Quantitative evaluation of liver function with T1 relaxation time index on Gd-EOB-DTPA-enhanced MRI: Comparison with signal intensity-based indices

To evaluate whether the reduction rate of T1 relaxation time of the liver (T1 relaxation time index) before and 20 minutes after gadolinium‐ethoxybenzyl‐diethylenetriaminepentaacetic acid (Gd‐EOB‐DTPA) injection has the potential to serve as an magnetic resonance imaging (MRI)‐based liver function test in comparison with signal intensity‐based indices.

Reduction of oxidative stress in liver cancer patients by oral green tea polyphenol tablets during hepatic arterial infusion chemotherapy

Hepatic arterial infusion chemotherapy (HAI) using an implanted port system is the standard regimen for primary and metastatic liver cancers (MLCs). However, there have been few studies concerning HAI-induced oxidative stress and damage to the liver or other organs. The aim of the present study was to investigate the ability of green tea polyphenols (GTPs) to reduce the oxidative stress or increase the biological antioxidative potential in HAI-treated patients. A total of 19 patients with inoperable hepatocellular carcinoma (HCC) or MLC from colorectal malignancy were eligible for HAI with cisplatin (CDDP) and 5-fluorouracil (5FU). The study subjects were randomly assigned to either a 3 or a 6 oral GTP tablets per day group. Each tablet had a GTP content equivalent to 79 mg of epigallocatechin-3-gallate. The oxidative stress was assessed by measuring the levels of derivatives of reactive oxygen metabolites (d-ROMs) and the biological antioxidative potential (BAP) values in patient plasma using the Free Radical Analytical System 4 (FRAS4), and correlating the results with clinical laboratory data for the patients. The levels of d-ROMs were significantly reduced by the oral intake of 6 GTP tablets for 6–9 months (P=0.0463) but were not significantly reduced by the oral intake of 3 GTP tablets daily. BAP values remained constant in the 3 and 6 tablet groups for 6–9 months during the follow-up study. The total serum bilirubin (T-bil) levels increased significantly at 3 (P=0.028) and 9 (P=0.0151) months and the red blood cell (RBC) count decreased at 6 months (P=0.0458) after intake for the 6 GTP tablet group. Alkaline phosphatase (ALP) levels increased significantly at 9 months (P=0.0298). Cholinesterase (ChE) decreased significantly at 9 (P= 0.0127) and 12 (P= 0.0207) months after intake for the 3 GTP tablet group. The results indicate that the daily intake of 6 GTP tablets containing 474 mg polyphenols significantly reduces HAI-induced oxidative stress in HCC or MLC patients while the antioxidative potentials of the patients remain constant.

Gd-EOB-DTPA-enhanced magnetic resonance imaging features of hepatic hemangioma compared with enhanced computed tomography.

AIMnTo clarify features of hepatic hemangiomas on gadolinium-ethoxybenzyl-diethylenetriaminpentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) compared with enhanced computed tomography (CT).nnnMETHODSnTwenty-six patients with 61 hepatic hemangiomas who underwent both Gd-EOB-DTPA-enhanced MRI and enhanced CT were retrospectively reviewed. Hemangioma appearances (presence of peripheral nodular enhancement, central nodular enhancement, diffuse homogenous enhancement, and arterioportal shunt during the arterial phase, fill-in enhancement during the portal venous phase, and prolonged enhancement during the equilibrium phase) on Gd-EOB-DTPA-enhanced MRI and enhanced CT were evaluated. The degree of contrast enhancement at the enhancing portion within the hemangioma was visually assessed using a five-point scale during each phase. For quantitative analysis, the tumor-muscle signal intensity ratio (SIR), the liver-muscle SIR, and the attenuation value of the tumor and liver parenchyma were calculated. The McNemar test and the Wilcoxons signed rank test were used to assess the significance of differences in the appearances of hemangiomas and in the visual grade of tumor contrast enhancement between Gd-EOB-DTPA-enhanced MRI and enhanced CT.nnnRESULTSnThere was no significant difference between Gd-EOB-DTPA-enhanced MRI and enhanced CT in the presence of peripheral nodular enhancement (85% vs 82%), central nodular enhancement (3% vs 3%), diffuse enhancement (11% vs 16%), or arterioportal shunt (23% vs 34%) during arterial phase, or fill-in enhancement (79% vs 80%) during portal venous phase. Prolonged enhancement during equilibrium phase was observed less frequently on Gd-EOB-DTPA-enhanced MRI than on enhanced CT (52% vs 100%, P < 0.001). On visual inspection, there was significantly less contrast enhancement of the enhancing portion on Gd-EOB-DTPA-enhanced MRI than on enhanced CT during the arterial (3.94 ± 0.98 vs 4.57 ± 0.64, respectively, P < 0.001), portal venous (3.72 ± 0.82 vs 4.36 ± 0.53, respectively, P < 0.001), and equilibrium phases (2.01 ± 0.95 vs 4.04 ± 0.51, respectively, P < 0.001). In the quantitative analysis, the tumor-muscle SIR and the liver-muscle SIR observed with Gd-EOB-DTPA-enhanced MRI were 0.80 ± 0.24 and 1.28 ± 0.33 precontrast, 1.92 ± 0.58 and 1.57 ± 0.55 during the arterial phase, 1.87 ± 0.44 and 1.73 ± 0.39 during the portal venous phase, 1.63 ± 0.41 and 1.78 ± 0.39 during the equilibrium phase, and 1.10 ± 0.43 and 1.92 ± 0.50 during the hepatobiliary phase, respectively. The attenuation values in the tumor and liver parenchyma observed with enhanced CT were 40.60 ± 8.78 and 53.78 ± 7.37 precontrast, 172.66 ± 73.89 and 92.76 ± 17.92 during the arterial phase, 152.76 ± 35.73 and 120.12 ± 18.02 during the portal venous phase, and 108.74 ± 18.70 and 89.04 ± 7.25 during the equilibrium phase, respectively. Hemangiomas demonstrated peak enhancement during the arterial phase, and both the SIR with Gd-EOB-DTPA-enhanced MRI and the attenuation value with enhanced CT decreased with time. The SIR of hemangiomas was lower than that of liver parenchyma during the equilibrium and hepatobiliary phases on Gd-EOB-DTPA-enhanced MRI. However, the attenuation of hemangiomas after contrast injection was higher than that of liver parenchyma during all phases of enhanced CT.nnnCONCLUSIONnProlonged enhancement during the equilibrium phase was observed less frequently on Gd-EOB-DTPA-enhanced MRI than enhanced CT, which may exacerbate differentiating between hemangiomas and malignant tumors.

Diagnosis of Metastases from Postoperative Differentiated Thyroid Cancer: Comparison between FDG and FLT PET/CT Studies

PURPOSEnTo compare positron emission tomography (PET)/computed tomography (CT) studies performed with the glucose analog fluorine 18 ((18)F) fluorodeoxyglucose (FDG) and the cell proliferation tracer (18)F fluorothymidine (FLT) in the diagnosis of metastases from postoperative differentiated thyroid cancer.nnnMATERIALS AND METHODSnThe institutional ethics review board approved this prospective study. From March 2010 to February 2012, 20 patients (mean age, 53 years; age range, 22-79 years) with postoperative differentiated thyroid cancer underwent both FDG and FLT PET/CT as a staging work-up before radioiodine therapy. In each patient, 28 anatomic areas were set and analyzed for lymph node and distant metastases. The McNemar exact or χ(2) test was used to examine differences in diagnostic indexes in the detection of lymph node and distant metastases between both tracer PET/CT studies.nnnRESULTSnThere were 34 lymph node metastases and/or 73 distant metastases (70 metastases in lung and one each in bone, nasopharynx, and brain) in 13 patients. At patient-based analysis, the sensitivity, specificity, and accuracy were 92% (12 of 13 patients), 86% (six of seven patients), and 90% (18 of 20 patients), respectively, for FDG PET/CT and 69% (nine of 13 patients), 29% (two of seven patients), and 55% (11 of 20 patients) for FLT PET/CT. The accuracy of FDG PET/CT was significantly better than that of FLT PET/CT (P = .023). At lesion-based analysis, the sensitivity, specificity, and accuracy for diagnosing lymph node metastases were 85% (29 of 34 lesions), 99.6% (245 of 246 lesions), and 97.9% (274 of 280 lesions), respectively, for FDG PET/CT and 50% (17 of 34 lesions), 90.7% (223 of 246 lesions), and 85.7% (240 of 280 lesions) for FLT PET/CT. The sensitivity, specificity, and accuracy for diagnosing distant metastases were 45% (33 of 73 lesions), 100% (207 of 207 lesions), and 85.7% (240 of 280 lesions), respectively, for FDG PET/CT and 6.8% (five of 73 lesions), 100% (207 of 207 lesions), and 75.7% (212 of 280 lesions) for FLT PET/CT. The sensitivity (P = .002), specificity (P < .001), and accuracy (P < .001) of FDG PET/CT in the diagnosis of lymph node metastases were superior to those of FLT PET, as were the sensitivity (P < .001) and accuracy (P < .001) in the diagnosis of distant metastases.nnnCONCLUSIONnFDG PET/CT is superior to FLT PET/CT in the diagnosis of postoperative differentiated thyroid cancer lymph node and distant metastases. Thus, FDG PET/CT is more suitable than FLT PET/CT for examining recurrence of postoperative differentiated thyroid cancer.

Are catecholamine-derived indexes in adrenal venous sampling useful for judging selectivity and laterality in patients with primary aldosteronism?

In order to investigate retrospectively whether catecholamine concentrations obtained by adrenal venous sampling (AVS) are useful for lateralization of the aldosteronoma-bearing adrenal gland. The study population comprised 35 patients (10 men, 25 women; mean age, 49.8xa0years) with aldosteronoma and 18 patients (9 men, 9 women; mean age, 51.8xa0years) with non-functioning adenoma who underwent AVS between 1994 and 2010. In all cases, AVS was performed without administering adrenocorticotrophic hormone. Successful or unsuccessful adrenal vein blood sampling (selectivity) was judged by the ratio of plasma cortisol (C) level in each adrenal vein to that in the infra-renal inferior vena cava [C(side)/C(IVC)] as a gold standard, with successful selectivity defined using four different cut-off values [C(side)/C(IVC)xa0≥xa03.0, 2.0, 1.36 or 1.1]. Receiver operating characteristics (ROC) analyses were conducted to determine: (1) degree of selectivity; and (2) the best catecholamine (epinephrine, norepinephrine, and dopamine)-derived index for lateralization of the aldosteronoma-bearing adrenal gland. Among the catecholamine-derived indexes, the epinephrine concentration ratio of adrenal vein to IVC was the most reliable for all four different cut-off values in the evaluation of adrenal vein selectivity. Meanwhile, the ratio of aldosterone to norepinephrine between dominant and non-dominant sides was the most reliable index (right: area under the curve (AUC), 0.965xa0±xa00.024; 95xa0% confidence interval (CI), 0.874–0.996; left: AUC, 0.937xa0±xa00.033; 95xa0% CI, 0.834–0.985) for lateralization of the aldosteronoma-bearing gland. Catecholamine concentrations obtained by AVS are useful for not only judging selectivity, but also lateralization of the aldosteronoma-bearing gland.

Computed tomographic features of two cases of acute gastric anisakiasis

Little is known about the detailed computed tomography (CT) features of acute gastric anisakiasis. Our two cases showed transiently swollen gastric folds comprised of the remarkably thickened contrast little-enhanced submucosal layer with little-thickened contrast-enhanced mucosal and muscular-serosal layers on multi-detector row CT. When CT demonstrates the swollen gastric folds in acute abdomen, acute gastric anisakiasis should be included in the differential diagnosis.

A black adrenal adenoma difficult to be differentiated from a malignant adrenal tumor by CT, MRI, scintigraphy and FDG PET/CT examinations

Black adrenal adenoma (BAA) is an adrenal adenoma which contains lipofuscin and has a black or brown appearance. Preoperative diagnosis of BAA is difficult because it is diagnosed by pathologic findings. We report a case of an incidentally discovered non-hyperfunctioning BAA in the left adrenal gland of a 58-year-old man. It showed an oval lipid-poor mass, 3xa0cmxa0×xa02xa0cm in size on computed tomography (CT) and magnetic resonance imaging (MRI), no avid uptake of 131I-norcholesterol and 123I-meta-iodobenzylguanidine (MIBG) on scintigraphy, and intense avid uptake of 18F-fluorodeoxyglucose (FDG) on positron emission tomography–CT (PET/CT). FDG PET/CT showed that it was a hypermetabolic lesion, more intense than the activity of the liver, and the maximum standardized uptake value was 5.6 on 1-h early imaging and 8.3 on 2-h delayed imaging, suggesting a malignant tumor. BAA is a clinically rare benign adrenal adenoma, but it should be kept in mind that BAA may exhibit false-positive results for malignancy or inconclusive results for benignity with modern imaging modalities including CT, MRI, adrenal scintigraphy with radiolabelled cholesterol and radiolabelled MIBG, and FDG-PET like this case.