Hisao Tonami

FDG PET in the evaluation of the aggressiveness of pulmonary adenocarcinoma : correlation with histopathological features

2-[Fluorine-18]fluoro-2-deoxy-d-glucose (FDG) uptake within the primary lesion correlates with survival on positron emission tomography (PET) studies of patients with non-small cell lung cancer. The more metabolically active the tumour, the worse the outcome. The aim of this study was to determine whether a correlation exists between aggressiveness as determined by pathology and the findings of FDG PET in pulmonary adenocarcinoma. Thirty-five patients with 38 adenocarcinomas of the lung were studied. All patients underwent thoracotomy within 4 weeks of the FDG PET study. For semiquantitative analysis, standardized uptake values (SUVs) were calculated. Patients were classified into high SUV (⩾4.0) and low SUV (<4.0) groups. The degree of FDG uptake (SUVs) in primary lung lesions was correlated with the histopathological features of aggressiveness (pleural involvement, vascular invasion or lymphatic permeation). The mean SUV of aggressive adenocarcinomas (4.36±1.94, n = 22) was higher than that of non-aggressive ones (1.53±0.88, n = 16) (P<0.0001). Tumours with a high FDG uptake have a significantly higher likelihood of aggressiveness than those with a low FDG uptake (P = 0.0004). Analysis by the Kaplan-Meier methods revealed that the groups had different prognoses (log-rank test, P = 0.0099). The high SUV group had a significantly worse prognosis. In conclusion, a correlation was seen between aggressiveness as determined by pathology and glucose metabolism as measured by FDG PET in adenocarcinoma of the lung. FDG PET may be used as a non-invasive diagnostic technique in measuring aggressiveness and prognosis in patients with pulmonary adenocarcinoma.

Creutzfeldt-Jakob disease: serial changes on diffusion-weighted MRI.

We present serial changes on diffusion-weighted MRI (DWI) in a patient with Creutzfeldt-Jakob disease (CJD). DWI revealed serial changes of abnormal hyperintense lesions that had become more extensive and conspicuous with progression of neurologic findings, more sensitively than conventional MRI. In the late stage, disappearance of abnormal hyperintense lesions on DWI was observed. DWI proved to be particularly useful for monitoring the progression of CJD.

A comparative study between MR sialography and salivary gland scintigraphy in the diagnosis of Sjögren syndrome.

Purpose The purpose of this work was to compare the diagnostic accuracy of MR sialography with that of salivary gland scintigraphy in Sjögren syndrome. Method One hundred thirty patients clinically suspected of having Sjögren syndrome were examined by MR sialography and salivary gland scintigraphy. A labial gland biopsy was performed in all patients. Imaging findings of MR sialography and salivary gland scintigraphy were compared with the results of labial gland biopsy. Results From the results of labial gland biopsy, the diagnosis of Sjögren syndrome was established in 80 patients. Abnormally high T2 signal intensity areas on MR sialography and decreased uptake and delayed excretion of [99mTc]pertechnetate on salivary gland scintigraphy were well seen in patients with Sjögren syndrome. For the diagnosis of Sjögren syndrome, salivary gland scintigraphy showed higher sensitivity than MR sialography. On the other hand, MR sialography showed higher specificity and positive predictive value (PPV) than salivary gland scintigraphy. Overall diagnostic accuracy was 83% for MR sialography and 72% for salivary gland scintigraphy. Conclusion The high PPV of MR sialography suggests that MR sialography is the preferred imaging modality in patients suspected of having Sjögren syndrome.

Clinical and imaging findings of lymphoma in patients with Sjögren syndrome.

Objective To describe and correlate the clinical and imaging findings of lymphomas in patients with Sjögren syndrome. Methods The authors reviewed the medical and imaging records of 27 cases of lymphoma from among a total of 463 patients with Sjögren syndrome. The estimated prevalence of lymphoma in patients with Sjögren syndrome was 5.8%. There were 22 women and 5 men. Histopathologically, 26 of the 27 neoplasms were non-Hodgkin lymphoma, including 6 mucosa-associated lymphoid tissue lymphomas, and the other neoplasm was Hodgkin lymphoma. The clinical and imaging findings of lymphomas were analyzed. Results No obvious correlations were present between the duration or severity of Sjögren syndrome and the lymphoma development. At the initial diagnosis, extranodal involvement was observed in 14 (52%) of the 27 patients, including the salivary gland (n = 9), lacrimal gland (n = 2), lung (n = 2), and thyroid gland (n = 1), mostly in the neck organs. On the other hand, nodal involvement was observed in 21 (78%) of the 27 patients. Of these 21 patients, 19 had at least cervical lymph node involvement. Conclusion Patients with Sjögren syndrome are at increased risk of lymphoma development. Because most lymphomas initially involve the neck organs, including the lymph nodes, meticulous imaging studies mainly focused on the cervical regions are recommended in the follow-up of patients with Sjögren syndrome.

Value of whole-body FDG PET in management of lung cancer

Abstract18F-fluorodeoxyglucose (FDG) PET imaging provides physiologic and metabolic information that characterizes lesions that are indeterminate by CT. FDG PET imaging is sensitive to the detection of lung cancer in patients who have indeterminate lesions on CT, whereas low grade malignancy such as bronchioloalveolar carcinoma and carcinoid may be negative on FDG PET. The specificity of PET imaging is less than its sensitivity because some inflammatory processes, such as active granulomatous infections, avidly accumulate FDG. This possibility should be kept in mind in the analysis of PET studies of glucose metabolism aimed at differentiating malignant from benign solitary pulmonary nodules. FDG uptake is considered to be a good marker of cell differentiation, proliferative potential, aggressiveness, and the grade of malignancy in patients with lung cancer. FDG PET accurately stages the distribution of lung cancer. Several studies have documented the increased accuracy of PET compared with CT in the evaluation of the hilar and mediastinal lymphnode status in patients with lung cancer. Whole-body PET studies detect metastatic disease that is unsuspected by conventional imaging. Management changes have been reported in up to 41% of patients on the basis of the results of whole-body studies. Whole-body FDG PET is also useful for the detection of recurrence. Several studies have indicated that the degree of FDG uptake in primary lung cancer can be used as an independent prognostic factor. Thus, whole-body FDG PET is clinically very useful in the management of lung cancer.

Lactate, choline, and creatine levels measured by vitro 1H-MRS as prognostic parameters in patients with non-small-cell lung cancer

To determine the biochemical characteristics of lung cancer tissue using in vitro 1H‐MRS, and investigate the correlation between survival probabilities and lactate (Lac), creatine (Cr), and choline (Cho) concentrations measured by in vitro 1H‐MRS.

Chordoid glioma of the third ventricle: CT and MR findings.

We present a case of chordoid glioma involving the third ventricle in a 42-year-old woman. CT and MR showed a homogeneously enhancing mass occupying the third ventricle, with a cystic component. Chordoid glioma should be included in the differential diagnosis of uncommon masses of the third ventricle in middle-aged women.

Fractional change in apparent diffusion coefficient as an imaging biomarker for predicting treatment response in head and neck cancer treated with chemoradiotherapy.

BACKGROUND AND PURPOSE: ADC provides a measure of water molecule diffusion in tissue. The aim of this study was to evaluate whether the fractional change in ADC during therapy can be used as a valid predictive indicator of treatment response in head and neck squamous cell carcinoma treated with chemoradiotherapy. MATERIALS AND METHODS: Forty patients underwent DWI at pretreatment and 3 weeks after the start of treatment. The pretreatment ADC, fractional change in ADC, tumor regression rate, and other clinical variables were compared with locoregional control and locoregional failure and were analyzed by using logistic regression analysis and receiver operating characteristic analysis. Furthermore, progression-free survival curves divided by the corresponding threshold value were compared by means of the log-rank test. RESULTS: The fractional change in ADCprimary, the fractional change in ADCnode, primary tumor volume, nodal volume, tumor regression ratenode, N stage, and tumor location revealed significant differences between locoregional failure and locoregional control (P < .05). In univariate analysis, the fractional change in ADCprimary, fractional change in ADCnode, tumor regression ratenode, N stage, and tumor location showed significant association with locoregional control (P < .05). In multivariate analysis, however, only the fractional change in ADCprimary was identified as a significant and independent predictor of locoregional control (P = .04). A threshold fractional change in ADCprimary of 0.24 revealed a sensitivity of 100%, specificity of 78.7%, and overall accuracy of 84.8% for the prediction of locoregional control. Progression-free survival of the 2 groups divided by the fractional change in ADCprimary at 0.24 showed a significant difference (P < .05). CONCLUSIONS: The results suggest that the fractional change in ADCprimary is a valid imaging biomarker for predicting treatment response in head and neck squamous cell carcinoma treated with chemoradiotherapy.

Percutaneous laser discectomy: MR findings within the first 24 hours after treatment and their relationship to clinical outcome.

OBJECTIVE The purpose of this study was to evaluate the early MR appearances of the intervertebral disc obtained within 24 h after percutaneous laser discectomy and to determine if a correlation exists between the MR images and the clinical outcome. SUBJECTS AND METHODS Twenty-nine discs in 26 patients with contained lumbar disc herniation treated by laser were included. Laser intervention was performed using Ho:YAG laser system. The results were quantitatively analysed by measuring areal changes of the herniated mass on axial T1-weighted images and signal changes within the disc on sagittal T2-weighted images. Clinical outcomes were evaluated according to Japanese Orthopaedic Association score (JOA score), and recovery rates based on JOA score immediately and 1 year after treatment were calculated. RESULTS The recovery rate immediately after treatment was 53.1%, and increasing to 64.6% 1 year later. The size of the disc herniation ranged from 7% to 55% of the axial cross-section of the spinal canal pre-operatively and no significant changes were noted postoperatively. Also no correlation was found between the pre-operative herniation size and the recovery rate. The signal changes within the disc increased significantly after treatment, but no correlation was present between the signal changes and the recovery rate. In five patients, soft-tissue changes along the laser tract were well demonstrated on MR imaging. CONCLUSION Although immediate postoperative MR imaging shows early tissue changes induced by laser, our study has not proven that immediate postoperative MR imaging could predict the clinical outcome after percutaneous laser discectomy.

Mri of Subperiosteal Hematoma of the Orbit

Objective The MR findings of two cases of subperiosteal hematoma of the orbit are described. Materials and Methods We present two cases of subperiosteal hematoma of the orbit following minor head trauma, the first presenting with chronic progressive exophthalmos and the second with acute proptosis. Results Both cases showed a well-defined biconvex mass with a curvilinear hypointense band in the superior portion of the orbit. In Case 1 chronic hematoma demonstrated high signal on both T1− and T2-weighted imaging, and in Case 2 acute hematoma displayed intermediate signal on T1-weighted imaging and high signal on T2-weighted imaging. Follow-up MRI in Case 2 demonstrated the typical signal changes from acute to subacute hematoma. Conclusion Subperiosteal hematoma has a characteristic appearance on MRI which is virtually diagnostic. In proper clinical settings MRI is the modality of choice for the detection and characterization of this hematoma.