Soichi Akata

Evaluation of chest wall invasion by lung cancer using respiratory dynamic MRI

Conventional CT or MRI has low accuracy in assessing chest wall invasion in patients with peripheral lung cancer. For preoperative evaluation of chest wall invasion by peripheral lung cancer, respiratory dynamic (RD) MRI was carried out in 98 patients in whom conventional CT scan showed that the tumour was abutting the pleural surface, but there was no evidence of definite tumour invasion. We used 1.5‐T MR equipment. RD MR images were acquired by snapshot fast field echo sequence (repetition time = 8, echo time = 3, flip angle = 100) and 25 consecutive images were taken while the patient took deep breaths. These images were evaluated in cine mode to assess tumour movement along the chest wall. Sixty‐one patients underwent surgical resection of the tumour and RD MR findings were compared with those in pathological specimens. RD MR showed free tumour movement along the chest wall in 34 patients. At pathological examination, the RD MR findings were proved correct in all patients. Pathologically, 20 patients had chest wall invasion and their RD MR was positive (sensitivity 100%). There were seven false‐positive results among the 41 patients without chest wall invasion (specificity 82.9%). RD MR may improve the accuracy of conventional CT scan or MRI in the prediction of chest wall invasion of lung cancer, especially in patients in whom the results of conventional CT scan or MRI appear equivocal in the presence of a peripheral mass abutting the chest wall surface without obvious chest wall invasion.

Assessing liver function using dynamic Gd-EOB-DTPA-enhanced MRI with a standard 5-phase imaging protocol.

To evaluate liver function obtained by tracer‐kinetic modeling of dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) data acquired with a routine gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd‐EOB‐DTPA)‐enhanced protocol.

Cine MRI enables better therapeutic planning than CT in cases of possible lung cancer chest wall invasion

THE OBJECTIVE To evaluate the hypothesis that lung cancer treatment planning (whether or not to use induction therapy) can be improved if respiratory dynamic cine magnetic resonance imaging (RD MR) is used. METHOD We studied 100 lung cancer patients, 76 men and 21 women, scheduled for thoracotomies between May 1997 and December 2006 wherein it was unclear preoperatively whether chest wall invasion would be found. We evaluated the accuracy of RD MR as compared with the findings at operation and postoperative pathology. The accuracy of RD MRI for evaluating chest wall invasion was compared with the efficacy of CT and MRI within our own group of patients and with data from the studies of other investigators. RESULTS Concerning the evaluation of chest wall invasion, conventional computed tomography (CT) had 43.9% specificity, 60.0% sensitivity and 47.1% accuracy, while RD MR had 68.5% specificity, 100.0% sensitivity and 77.0% accuracy. RD MRI was particularly useful in the evaluation of cancers around 5 cm in diameter that were located adjacent to the diaphragm. Postoperative evaluation of superior sulcus tumor cases that had received induction therapy also showed that the RD MR procedure enabled an accurate decision in 87.5% of cases, and there were no false negative cases. CONCLUSIONS RD MR is more useful than CT or standard MRI for evaluating thoracic wall invasion. This noninvasive method enhances the reliability of deciding whether induction therapy should be employed.

Histological grade of differentiation of hepatocellular carcinoma: comparison of the efficacy of diffusion-weighted MRI with T2-weighted imaging and angiography-assisted CT.

Introduction: The purpose of this study is to determine the usefulness of diffusion‐weighted imaging (DWI) for evaluating the histological grade of differentiation of hepatocellular carcinoma (HCC) compared with T2‐weighted imaging (T2WI) and tumour haemodynamics.

CT scanning of bronchioloalveolar carcinoma: specific appearances

We reviewed CT scans in 38 cases with pathologically proved bronchioloalveolar carcinoma. CT revealed three CT patterns: solitary, pneumonic and diffuse forms. The solitary pattern (22 patients) had a high percentage of air bronchograms (95%), pleural indentation (77%) and spiculation (68%). The pneumonia-like pattern (16 lesions in 10 patients) had air bronchograms in all cases (100%), low attenuation (88%) and protrusion of interlobar fissures (63%). The diffuse form (six patients) had 2 or 3 mm diffuse small nodules scattered throughout the entire lung. CT of bronchioloalveolar carcinoma revealed many findings and was useful in recognizing the tumor distribution and extent. We conclude that CT is helpful for the diagnosis and evaluation of bronchioloalveolar carcinoma.

Venous hemangioma of the mediastinum

Abstract Mediastinal hemangiomas are rare tumors. We present a case of venous hemangioma of the mediastinum. Computed tomography shows anterior mediastinal solid mass without enhancement effects. We believe that it is necessary to include a mediastinal hemangioma for differential diagnosis, when little or no enhancement effects are noted at early and delayed CT examination.

High-quality 3-dimensional image simulation for pulmonary lobectomy and segmentectomy: results of preoperative assessment of pulmonary vessels and short-term surgical outcomes in consecutive patients undergoing video-assisted thoracic surgery

OBJECTIVES The aim of this study was to evaluate the effectiveness of 3-dimensional computed tomography (3D-CT) software in short-term surgical outcomes and the assessment of variations of pulmonary vessel branching patterns on performing video-assisted thoracic surgery (VATS). METHODS The study included 179 consecutive patients who had undergone VATS anatomical lung resection, of which 172 were lobectomies (96%) and 7 were segmentectomies (4%), from May 2011 through January 2013. There were 124 patients (69%) in whom 3D-CT was performed and 55 patients (31%) who had not undergone 3D-CT. Observed actual pulmonary vessel branching patterns by intraoperative findings or footage were compared with the 3D image findings. Various surgical outcomes, including the occurrence of postoperative complications, in this study defined as those of Grade 2 or above under the Clavien-Dindo classification system, and total operative time, were retrieved from available clinical records. RESULTS Among the 124 patients with preoperative 3D imaging, there were 5 (4%) conversions from VATS to thoracotomy. The incidence rate of patients with postoperative complications was 8% (n = 10), and there were no 30-day or 90-day mortalities. Pulmonary artery (PA) branches were precisely identified for 97.8% (309 of 316) of branches on 3D images, and the sizes of the seven undetected branches (five in the right upper lobe, two in the left upper lobe) ranged from 1 to 2 mm. The 3D images accurately revealed 15 cases (12%) of anomalous or unusual PA branches and 5 cases (4%) of variant pulmonary veins. Multivariate logistic regression analysis of the association with postoperative complications and operative time in 165 lung cancer patients demonstrated that male gender was the only statistically significant independent predictor of complications (risk ratio: 5.432, P = 0.013), and patients without 3D imaging tended to have operative complications (risk ratio: 2.852, P = 0.074), whereas conducting the 3D-CT (risk ratio: 2.282, P = 0.021) as well as intraoperative bleeding amount (risk ratio: 1.005, P = 0.005) had significant association with operative time. CONCLUSIONS High-quality 3D-CT images clearly revealed the anatomies of pulmonary vessels, which could play important roles in safe and efficient VATS anatomical resection.

Survival of a surgical series of lung cancer patients with synchronous multiple ground-glass opacities, and the management of their residual lesions

OBJECTIVES We reviewed the medical record of a series of patients with synchronous multiple lung cancers (SMLC), in an attempt to identify the optimal treatment strategy for multiple ground-glass opacities (GGOs). MATERIALS AND METHODS From 2004 to 2010, 1223 patients underwent complete resection of non-small cell lung cancer. Among these, there were 67 patients (5.5%) with SMLC with at least 1 of the nodules showing GGO appearance. SMLC was divided into the main cancer (MC) which was a main target based on its tumor size or radiological invasiveness and sub-nodules. According to consolidation/tumor ratio (CTR) on thin-section computed tomography, 67 cases were classified into GG-group (MC showing GGO-dominant lesion; CTR≤0.5) and GS-group (MC showing solid-dominant lesion; CTR>0.5). RESULTS There were 24 patients in the GG-group (36%) and 43 patients in the GS-group (64%). Surgical resections included 11 sublobar resections (SLs), 32 lobectomies, 19 lobectomy+SLs, and 4 bilobectomies. There were 39 patients with a total of 118 unresected GGOs after the initial surgery. Among them, the frequency of growth was 8% on a per-nodule basis with the median tumor doubling time of 1373 days, and new GGOs emerged in 15 patients (23%). Multivariate analysis demonstrated that larger size of MC and the GS-group was associated with poor prognosis, whereas growth of the residual GGOs, the development of new GGOs, or whether or not all GGOs were treated did not affect survival. The 5-year OS proportions were 95.8% for the GG-group and 68.0% for the GS-group (p=0.009), and 92.4% for a MC of ≤25 mm and 53.6% for a MC of >25 mm (p=0.008). CONCLUSION Survival of patients with multifocal GGOs is strongly affected by radiological findings of the MC. Strict surgical control for MC could be most important.

Association between high-resolution computed tomography findings and the IASLC/ATS/ERS classification of small lung adenocarcinomas in Japanese patients

OBJECTIVES The detection rate of small pulmonary nodules has recently increased and new techniques have been developed to improve diagnostic yield. The IASLC/ATS/ERS classification demonstrated a difference in prognosis depending on the histological subtypes of lung adenocarcinoma. We evaluated the association between high-resolution computed tomography (HRCT) findings and the classification of these tumors. METHODS We reviewed the data of 220 lung adenocarcinoma (≤3 cm) patients who received complete resection with lymph node dissection in our hospital. From the HRCT findings, the tumors were classified into the following 3 categories: pure-solid nodules, part-solid nodules, or pure ground-glass opacity (GGO) nodules. Pathological invasion factor (PIF) was evaluated by the degree of blood vessel invasion, lymphatic permeation, and visceral pleural invasion. RESULTS The tumors were classified as pure GGO nodules in 16 patients, part-solid nodules in 91, and pure-solid nodules in 113 from the HRCT findings. Tumors were diagnosed as noninvasive or minimally invasive adenocarcinomas (NMIADs) in 44 patients, and invasive adenocarcinomas (IADs) in 176. Lymph node metastasis was present in 31 patients (14.1%) and PIF in 101 (45.9%). All pure-solid nodules were IADs with a high PIF frequency (75.2%) or with lymph node metastasis (26.5%). All pure GGO nodules were NMIADs or lepidic-predominant adenocarcinomas. Among the part-solid nodules, IAD was detected in 67.0% of the patients and PIF in 16.5%. The consolidation/tumor (C/T) ratio and consolidation size were associated with IAD (optimal cut-off values: 0.4 and 8mm, respectively) and PIF (0.8 and 15 mm, respectively). CONCLUSIONS The HRCT findings correlated with the IASLC/ATS/ERS classification and were useful for evaluating the histological nature of the tumors. Most pure-solid tumors had the potential for high-grade malignancy, including PIF and lymph node metastasis. For part-solid tumors, the C/T ratio and consolidation size were important for predicting PIF and for diagnosing IAD according to this classification.

Distinguishing hepatic hemangiomas from metastatic tumors using T1 mapping on gadoxetic-acid-enhanced MRI.

OBJECTIVE The objective was to evaluate the usefulness of T1 mapping in distinguishing hepatic hemangiomas from metastatic tumors on gadoxetic-acid-enhanced magnetic resonance imaging. METHODS We examined 20 hemangiomas in 14 patients and 21 metastatic tumors in 11 patients. We performed T1 mapping using the double-flip angle method before and after the injection of gadoxetic acid. Quantitative evaluation was carried out using the pre- and post-contrast enhancement ratios (CERs), and qualitative evaluation was conducted to evaluate the added value of T1 mapping using receiver operating characteristics analysis. RESULTS The mean CERs of metastatic tumors at 70 s, 240 s and 20 min after the injection of gadoxetic acid were 1.54 (95% confidence interval: 1.37-1.71), 1.47 (1.34-1.6) and 1.30 (1.19-1.41); those of hemangiomas were 3.36 (2.41-4.31), 3.06 (2.44-3.68) and 2.20 (2.02-2.38), respectively. The mean CERs of hemangiomas were significantly higher than those of metastatic tumors (P<.05). When the mean CER cutoff value 20 min after the injection was set at 1.6, the diagnostic sensitivity of hepatic hemangiomas was 100%. There was no added value observed statistically in the qualitative evaluation of T1 mapping (P>.05). CONCLUSION It is valuable to evaluate quantitatively T1 mapping 20 min after hepatobiliary phase acquisition in the case of difficulty in distinguishing hepatic hemangiomas from metastatic tumors qualitatively.