Masamichi Koyama

FDG uptake heterogeneity evaluated by fractal analysis improves the differential diagnosis of pulmonary nodules

PURPOSE The present study aimed to determine whether fractal analysis of morphological complexity and intratumoral heterogeneity of FDG uptake can help to differentiate malignant from benign pulmonary nodules. MATERIALS AND METHODS We retrospectively analyzed data from 54 patients with suspected non-small cell lung cancer (NSCLC) who were examined by FDG PET/CT. Pathological assessments of biopsy specimens confirmed 35 and 19 nodules as NSCLC and inflammatory lesions, respectively. The morphological fractal dimension (m-FD), maximum standardized uptake value (SUV(max)) and density fractal dimension (d-FD) of target nodules were calculated from CT and PET images. Fractal dimension is a quantitative index of morphological complexity and tracer uptake heterogeneity; higher values indicate increased complexity and heterogeneity. RESULTS The m-FD, SUV(max) and d-FD significantly differed between malignant and benign pulmonary nodules (p<0.05). Although the diagnostic ability was better for d-FD than m-FD and SUV(max), the difference did not reach statistical significance. Tumor size correlated significantly with SUV(max) (r=0.51, p<0.05), but not with either m-FD or d-FD. Furthermore, m-FD combined with either SUV(max) or d-FD improved diagnostic accuracy to 92.6% and 94.4%, respectively. CONCLUSION The d-FD of intratumoral heterogeneity of FDG uptake can help to differentially diagnose malignant and benign pulmonary nodules. The SUV(max) and d-FD obtained from FDG-PET images provide different types of information that are equally useful for differential diagnoses. Furthermore, the morphological complexity determined by CT combined with heterogeneous FDG uptake determined by PET improved diagnostic accuracy.

Primary pituitary lymphoma diagnosis by FDG-PET/CT.

Primary pituitary lymphoma is extremely rare. We describe a 71-year-old man who presented with appetite loss and sudden visual loss. Brain magnetic resonance imaging showed a mass at the pituitary gland that was moderately and homogeneously enhanced with contrast media. F-18 fluorodeoxyglucose positron emission tomography combined with CT (FDG-PET/CT) performed for a systemic survey revealed focal moderate FDG uptake only in the pituitary gland. The mass was histologically diagnosed as non-Hodgkin lymphoma from a biopsy of the pituitary gland.

Fdg-pet Images of Acrometastases

Skeletal metastasis is common in patients with malignancy, but very few patients have acrometastasis, that is, metastasis to the hand or foot. We present 2 cases of acrometastasis from lung cancer where primary and metastatic foci were demonstrated on FDG-PET. The first case involves a 53-year-old man who complained of left foot pain and had osteolytic metastasis in the left calcaneus due to lung adenocarcinoma. True whole-body PET demonstrated lung cancer with calcaneal metastasis. Another case involves a 62-year-old man with large cell carcinoma of the right lung who complained of right wrist pain. Osteolytic metastasis of the hamate was demonstrated on images.

Evaluation of a revised version of computer-assisted diagnosis system, BONENAVI version 2.1.7, for bone scintigraphy in cancer patients

ObjectiveBONENAVI is a computer-assisted diagnosis system that analyzes bone scintigraphy automatically. We experienced more than a few segmentation errors with the previous BONENAVI version (2.0.5). We have since obtained a revised version (2.1.7) and evaluate it.MethodsBone scans of patients were analyzed by BONENAVI version 2.0.5 and a revised version 2.1.7 with regard to segmentation errors, sensitivity, and specificity. Patients with skeletal metastases from prostate cancer, lung cancer, breast cancer, and other cancers were included in the study as true-positive cases. Patients with no skeletal metastasis (regardless of hot spots), and patients with abnormal bone scans but no skeletal metastasis were included as negative cases. Bone-scan patients were subjected to artificial neural network (ANN) evaluation. Values equal to or above 0.5 were regarded as positive, and those below 0.5 as negative. The patients whose clinical status did not correspond to their ANN scores were assessed for any similarities.ResultsThe frequency of segmentation errors was statistically significantly reduced when using BONENAVI version 2.1.7. The differences in sensitivity and specificity for the results of version 2.0.5 versus version 2.1.7 were not different, giving a high Cohen’s kappa coefficient. In the patients who showed an increased ANN value with version 2.1.7, a few false-positive thoracic lesions were identified. Patients whose ANN value was significantly high with version 2.0.5 showed no tendencies.ConclusionRevised BONENAVI version 2.1.7 for bone scintigraphy was superior with regard to segmentation errors. However, its sensitivity and specificity were similar to those of version 2.0.5. The false-positive identification of thoracic lesions in revised version 2.1.7 might be subject to remedy.

Reoperative sentinel lymph node biopsy for ipsilateral breast tumor recurrence after previous axillary lymph node dissection: Report of a case

Sentinel lymph node biopsy has become a standard component of the evaluation of early-stage breast cancer, with a gradually increasing number of indications in this patient population. This report presents the case of a patient who underwent reoperative sentinel lymph node biopsy as part of an evaluation of ipsilateral breast tumor recurrence; she had previously undergone axillary lymph node dissection. Preoperative lymphoscintigraphy showed aberrant lymphatic drainage, and all three sentinel lymph nodes were positive for cancer. Although the optimal management of regional lymph nodes in patients with ipsilateral breast tumor recurrence who have already undergone axillary lymph node dissection has not been established, reoperative sentinel lymph node biopsy in this setting may therefore potentially enable the identification of subclinical, aberrantly located nodal metastasis.

Contralateral axillary node metastasis from recurrence after conservative breast cancer surgery.

Sentinel lymph node detection (SLND) with radiocolloid has become widely used for evaluation of nodal metastasis in primary breast cancer. However, the procedure for recurrent breast cancer is not well established. Contralateral axillary node metastasis is uncommon. We report 2 cases of contralateral axillary node metastasis with recurrent breast cancer. In the first case, contralateral node metastasis was found by SLND. In the other case without SLND, contralateral node metastasis developed after resection of local recurrence. FDG-avid contralateral node was pathologically diagnosed as metastasis. The SLND might be useful in patients with local recurrence after conservative breast cancer surgery.

Sinonasal oncocytic Schneiderian papilloma accompanied by intravascular lymphoma: A case report on FDG-PET/CT imaging.

Introduction:F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) is useful for the staging and assessment of treatment response in patients with lymphoma. Occasionally, benign lesions demonstrate avid FDG uptake and result in false positive findings. Case:We report the case of an 82-year-old man presenting with cutaneous lesions, which were histopathologically diagnosed as intravascular lymphoma. FDG-PET/CT for staging demonstrated an FDG-avid mass extending from the right maxillary sinus to the nasal cavity, moderate uptake in the adrenal glands, mild uptake in the knee and the foot, and faint uptake in the skin and subcutaneous tissue of the legs. He subsequently underwent biopsy of the paranasal mass, which was diagnosed as oncocytic Schneiderian papilloma without lymphoma invasion. Glucose transporter (GLUT) 1 staining was highly positive in the papilloma cells, resulting in high FDG avidity. After completion of chemotherapy, the abnormal FDG uptakes in the skin, soft tissue, and adrenal glands disappeared on PET/CT. However, avid FDG uptake persisted in the sinonasal Schneiderian papilloma for 15 months before regression. Conclusion:Benign tumors with oncocytic components may show avid FDG uptake. Therefore, correct diagnosis of oncocytic Schneiderian papilloma on FDG images is difficult when other accompanying malignant tumors, especially lymphoma, are present. If post-therapeutic PET/CT images show a discordant lesion, oncocytic tumors, albeit uncommon, should be considered in the differential diagnoses.

Radiation-induced osteosarcoma might mimic metastatic bone lesions: a case with bone scan and FDG PET/CT imaging.

We report on a 53-year-old woman with osteosarcoma of the skull who underwent radiation therapy for metastatic brain tumor. She had a history of uterine endometrial cancer treated with chemotherapy and surgery 9 years previously. FDG PET/CT for surveillance showed nodular accumulation at the right suprainguinal region and very avid accumulation at the left side of the occipital bone. Bone scan showed increased accumulation at the same portion of the occipital bone. The occipital tumor was surgically removed and diagnosed as radiation-induced osteosarcoma.

FDG PET imaging in a patient with primary seminoma of the prostate.

Primary seminoma of the prostate is extremely rare. We describe a case of a 35-year-old man who presented with difficulty in urinating. Physical findings were unremarkable, but a rectal examination revealed a slightly hardened prostate with a nodule in the right lobe. Blood parameters were normal; however, blood chemistry revealed slightly elevated lactic dehydrogenase, and microscopic hematuria was evident. Serum prostate acid phosphate, carcinoembryonic antigen, and alpha-fetoprotein values were within normal limits. Both computed tomography and magnetic resonance images revealed a large mass in the prostate gland. A prostatic sarcoma or malignant lymphoma was initially suspected. A systemic survey using 18-fluoro-2-deoxyglucose (F-18 FDG) positron emission tomography revealed focal FDG uptake in the prostate gland. A prostatic biopsy of the mass was histologically diagnosed to reveal an extragonadal seminoma.