Tsutomu Araki

BACKGROUND: Stereotactic irradiation (STI) has been actively performed using various methods to achieve better local control of Stage I nonsmall cell lung carcinoma (NSCLC) in Japan. The authors retrospectively evaluated results from a Japanese multiinstitutional study. METHODS: Patients with Stage I NSCLC (n = 245; median age, 76 years; T1N0M0, n = 155; T2N0M0, n = 90) were treated with hypofractionated high-dose STI in 13 institutions. Stereotactic three-dimensional treatment was performed using noncoplanar dynamic arcs or multiple static ports. A total dose of 18-75 gray (Gy) at the isocenter was administered in 1-22 fractions. The median calculated biologic effective dose (BED) was 108 Gy (range, 57-180 Gy). RESULTS: During follow-up (median, 24 months; range, 7-78 months), pulmonary complications of National Cancer Institute-Common Toxicity Criteria Grade > 2 were observed in only 6 patients (2.4%). Local progression occurred in 33 patients (14.5%), and the local recurrence rate was 8.1% for BED > or = 100 Gy compared with 26.4% for < 100 Gy (P < 0.05). The 3-year overall survival rate of medically operable patients was 88.4% for BED > or = 100 Gy compared with 69.4% for < 100 Gy (P < 0.05). CONCLUSIONS: Hypofractionated high-dose STI with BED < 150 Gy was feasible and beneficial for curative treatment of patients with Stage I NSCLC. For all treatment methods and schedules, local control and survival rates were better with BED > or = 100 Gy compared with < 100 Gy. Survival rates in selected patients (medically operable, BED > or = 100 Gy) were excellent, and were potentially comparable to those of surgery.

PURPOSE: To describe imaging findings of early hepatocellular carcinoma (HCC) at gadoxetic acid-enhanced magnetic resonance (MR) imaging, dynamic contrast material-enhanced computed tomography (CT), CT during arterial portography (CTAP), and CT during hepatic arteriography (CTHA) and to compare the diagnostic performance of each modality for small (≤ 2 cm) HCC. MATERIALS AND METHODS: The institute ethics committee deemed study approval unnecessary. One hundred eight resected small lesions in 64 patients were diagnosed as a dysplastic nodule (DN) (n = 12), progressed HCC (n = 66), or early HCC (n = 30). All but two patients underwent all imaging examinations. The imaging characteristics of the lesions with each modality were determined. To evaluate the diagnostic performance of the modalities, two radiologists graded the presence of HCC with use of a five-point confidence scale. The area under the receiver operating characteristic curve (A(z)), sensitivity, and specificity of each modality were compared. RESULTS: The imaging features that are statistically significant for differentiating an early HCC from a DN include fat-containing lesions at dual-echo T1-weighted MR imaging (seen in 16 of the 30 early HCCs and none of the DNs), low attenuation at unenhanced CT (seen in 13 of the 30 early HCCs and none of the DNs), low attenuation at CTAP (seen in 11 of the 30 early HCCs and none of the DNs), and low signal intensity at hepatocyte phase gadoxetic acid-enhanced MR imaging (seen in 29 of the 30 early HCCs and none of the DNs). The diagnostic performance of gadoxetic acid-enhanced MR imaging (A(z), 0.98 and 0.99) was significantly greater than that of contrast-enhanced CT (A(z), 0.87) and CTHA-CTAP (A(z), 0.85 and 0.86) owing to its significantly higher sensitivity (P < .001). CONCLUSION: Gadoxetic acid-enhanced MR imaging is the most useful imaging technique for evaluating small HCC, including early HCC.

OBJECTIVE: The purpose of this study was to determine the usefulness of diffusion-weighted MR imaging with single-shot echoplanar imaging in characterizing focal hepatic lesions by apparent diffusion coefficient (ADC) and contrast-to-noise ratio (CNR) measurements. MATERIALS AND METHODS: Diffusion-weighted imaging on a 1.5-T MR unit was performed in 46 patients with 74 known focal hepatic lesions (11 hemangiomas, 15 metastases, and 48 hepatocellular carcinomas [HCCs]). Mean values for ADCs and CNRs of all lesions were calculated. Mean values for CNRs with diffusion-weighted imaging were also compared with those for breath-hold T2-weighted fast spin-echo images. RESULTS: The mean values for ADCs were different for each type of tumor (5.39 x 10(-3) mm2/sec +/- 1.23 in hemangiomas, 2.85 x 10(-3) mm2/sec +/- 0.59 in metastases, and 3.84 x 10(-3) mm2/sec +/- 0.92 in HCCs), and each of them was significantly greater than the mean values for ADCs of the normal liver (2.28 x 10(-3) mm2/sec +/- 1.23 in normal liver [p < .05] except metastasis versus normal liver [p < .1]). Also, the mean values for ADCs were based on differences of ADC values. Only four (6%) of 63 malignant tumors (three HCCs and one metastasis) could not be differentiated from hemangiomas. The mean value for CNRs with diffusion-weighted images (14.4 +/- 8.54 in HCC and 29.0 +/- 6.79 in metastasis) was significantly higher than the mean values for CNRs obtained with T2-weighted fast spin-echo images in both metastases and HCCs (p < .05), whereas no significant difference was seen for hemangiomas. CONCLUSION: Mean values for ADCs differed for the three types of the hepatic lesions and were higher than ADCs of the normal liver. We suggest that diffusion-weighted imaging may be useful for increased detection of HCCs and metastases and in distinguishing these entities from hemangiomas.