Primary Pulmonary Lymphoepithelioma-like Carcinoma on FDG PET/CT

A 69-year-old male smoker was referred to ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) with the indication of a suspicious solitary pulmonary nodule. FDG PET/CT determined a 2.5?×?2-cm soft-tissue lesion (SUVmax, 16.2) with spiculated margins in the hilum of the right lung. A 1-cm diameter lymphadenopathy on the right hilum with an SUVmax of 3.2 was also determined. Transbronchial biopsy of the right hilar lymphadenopathy did not reveal any malignant features in histopathologic examination, and it was determined to be reactive. The patient underwent a right upper lobe segmentectomy, and the histopathologic evaluation revealed that the tumor was a primary lymphoepithelioma-like carcinoma (LELC) of the lung with negative Epstein-Barr virus (EBV) on in situ hybridization studies. In this case report, we mainly focus on the FDG avidity of this very rare kind of tumor comparatively with previous reports and possible explanations of discordancy in FDG avidity in relation to histopathologic characteristics.     

Recurrent thymoma: radiological (CT and FDG-PET) and histological (WHO criteria) features

A 66-year-old man, who had undergone surgical resection of a primary noninvasive thymoma (type B1) in the right anterolateral mediastinum 6 years before, underwent follow-up computed tomography (CT) scanning. The CT scan revealed a few nodules located at the posterior portion of the right thoracic base and just behind the right upper anterior chest wall. Subsequent fluorodeoxyglucose positron emission tomography (FDG-PET) scans showed multiple foci with high [standard uptake value (SUV) 4.3] and low (SUV 2.6) FDG uptake in the right lower posterior area and right upper anterior area of the chest, respectively. The fusion image of the CT and FDG-PET scans demonstrated that the areas of the increased FDG uptake corresponded to those of the nodules on the CT scan. All of the nodules were successfully removed surgically, and the histological features of the nodules indicated that they were type B1 or types B1 plus B2. We regarded the nodule located just behind the right upper anterior chest wall as a type B1 thymoma, whereas those in the posterior area of the right thoracic base as combined thymomas of types B1 plus B2. Our limited experience suggests that the degree of FDG uptake is a reflection of the subtype according to the World Health Organization (WHO) criteria. Furthermore, we showed the role of FDG-PET in the accurate assessment of recurrent thymoma and its therapeutic strategy.     

False-positive FDG-PET scan secondary to lipoid pneumonia mimicking a solid pulmonary nodule

Fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) scanning is useful in evaluating suspicious lesions of the lung. Our patient was a 65-year-old woman with a 45-pack-year smoking history who was referred for further evaluation because of a 3 cm × 3 cm solid lung nodule on computed tomography scan of the chest. FDG-PET scan revealed a standard uptake value of 3.2 suggestive of malignancy. The histology of the lung nodule was consistent with lipoid pneumonia, a benign condition frequently associated with inadvertent aspiration or inhalation of oily substances.     

Accuracy of transmission CT and FDG-PET in the detection of small pulmonary nodules with integrated PET/CT

Purpose The purpose of this study was to determine the accuracy of detection of small pulmonary nodules on quiet breathing attenuation correction CT (CTAC) and FDG-PET when performing integrated PET/CT, as compared with a diagnostic inspiratory CT scan acquired in the same imaging session.Methods PET/CT scans of 107 patients with a history of carcinoma (54 male and 53 female, mean age 57.3 years) were analyzed. All patients received an integrated PET/CT scan including a CTAC acquired during quiet respiration and a contrast-enhanced CT acquired during inspiration in the same session. Breathing CTAC scans were reviewed by two thoracic radiologists for the presence of pulmonary nodules. FDG-PET scans were reviewed to determine accuracy of nodule detection. Diagnostic CT was used as the gold standard to confirm or refute the presence of nodules.Results On the CTAC scans 200 nodules were detected, of which 183 were true positive (TP) and 17, false positive. There were 109 false negatives (FN). Overall, 51 (48%) patients had a false interpretation, including 19 in whom CT was interpreted as normal for lung nodules. The average size of the nodules missed was 3.8±2 mm (range 2–12 mm). None of the nodules missed on the CTAC scans were detected by PET. In the right lung there were 20 TP, 42 true negative (TN), 11 FP, and 34 FN interpretations with a sensitivity in nodule detection of 37% (CI 24–51%) and a specificity of 79% (CI 66–89%). In the left lungs there were 16 TP, 65 TN, 3 FP, and 23 FN interpretations, with a sensitivity of 41% (CI 26–58%) and a specificity of 96% (CI 88–99%).Conclusion The detection of small pulmonary nodules by breathing CTAC and FDG-PET is relatively poor. Therefore an additional diagnostic thoracic CT scan obtained during suspended inspiration is recommended for thorough evaluation of those patients in whom detection of pulmonary metastases is necessary for management.     

Volume of pulmonary lobes and segments in chronic obstructive pulmonary diseases calculated using newly developed three-dimensional software

Purpose  The aim of this study was to measure the volume of each pulmonary segment by volumetric computed tomography (CT) data using a newly developed three-dimensional software application and to identify the differences between those with chronic obstructive pulmonary disease (COPD) and controls. Materials and methods  CT scans of 11 COPD patients and 16 controls were included. The volume of each pulmonary segment was measured by each of two operators to evaluate the reproducibility of the software. This measured volume was then divided by the total lung volume to revise individual variations. Results  Volumes of the right (rt) S2, rt S5, left (lt) S1 + S2, lt S3, and lt S5 were significantly larger in COPD patients than in controls (P < 0.05). Regarding the ratio of the volume of each pulmonary segment per total lung volume, the areas of rt S2 and lt S1 + S2 were significantly larger in COPD patients than in controls (P < 0.05), whereas lt S10 was significantly smaller in COPD patients than in controls (P < 0.05). Conclusion  We measured the volume of each pulmonary segment based on volumetric CT data using this software. In addition, we demonstrated that the upper lung volume of COPD subjects was larger than that of controls, whereas the lower lung volumes were almost the same.     

Widespread metastases from sarcomatoid renal cell carcinoma detected by 18F-FDG positron emission tomography/computed tomography

We present a case of sarcomatoid renal cell carcinoma (RCC). Although preoperative computed tomography (CT) scans demonstrated small lung and pleural nodules and mediastinal lymphadenopathy, these findings were not conclusive for metastases. Whole-body fluorine-18 fluorodeoxyglucose positron emission tomography and CT (FDG-PET/CT) performed 15 days after right nephrectomy showed intense FDG uptake in the aforementioned lesions (lung and pleural nodules, mediastinal lymph nodes). Unexpectedly, focal increased FDG uptake was found in the right infraspinatus muscle. FDG-PET/CT was considered useful for evaluating distant metastases and thus portending the aggressive nature of sarcomatoid RCC.     

Upper pole of a duplex kidney mimicking adrenal incidentaloma in 18F-fluoro-2-deoxy-D-glucose positron emission tomography: a pitfall in diagnosis

18F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) has proved to be valuable in the diagnosis and management of a variety of malignancies, but is still limited in providing detailed anatomical information. According to the literature, an adrenal incidentaloma with high FDG uptake usually indicates malignancy and requires further investigation. However, accurate localization of the adrenal gland in FDG-PET is difficult without the presence of surrounding well-visualized organs, such as the kidney or liver. If these organs have a congenital anomaly or are altered due to a previous operation, misdiagnosis can occur. We present a case with right partial duplex kidney accompanied by abnormal urine retention in the upper pole, which was misinterpreted as an adrenal incidentaloma in FDG-PET. A subsequent CT scan revealed a normal right adrenal gland, but a right partial duplex kidney. Fusion of the PET and CT images showed that the right adrenal lesion seen in the PET image corresponded to the upper pole of the duplex kidney.     

The utility of FDG-PET/CT as an effective tool for detecting recurrent colorectal cancer regardless of serum CEA levels

Purpose

Tumor recurrence of colorectal cancers (CRC) is generally followed up by analyses of the serum carcinoembryonic antigen (CEA) levels. However, recent evidence suggests that tumor recurrence can also be visualized by 18F-fluoro-deoxyglucose emission tomography/computed tomography (FDG-PET/CT) in patients with normal CEA levels. We retrospectively evaluated the diagnostic performance of FDG-PET/CT in patients with suspected recurrence of CRC by comparing PET/CT performance in patients with normal CEA levels with PET/CT performance in patients with elevated CEA levels.

Methods

A total of 235 patients with CRC who had been treated with surgery and/or chemotherapy/radiotherapy underwent PET/CT for the detection of tumor recurrence. The patients [96 females and 139 males; age (mean?±?SD) 59.9?±?12.6?years; range 18?C85] were divided into 2 groups based on whether their CEA levels were normal (<5?ng/ml) (Group 1, n?=?118) or elevated (>5?ng/ml) (Group 2, n?=?117). All of the patients had suspected recurrence based on raised CEA levels, clinical symptoms, and/or tumor detection using other imaging modalities.

Results

Of the 235 patients, 172 (73.1?%) had disease recurrence confirmed by a pathological examination (either biopsy or surgical exploration) or clinical follow-up studies. The FDG-PET/CT study yielded a true positive in detecting recurrence in 169 (71.9?%) patients, a true negative in 53 (22.5?%) patients, a false negative in 3 (1.2?%) patients and a false positive in 10 (4.2?%) patients. CRC recurrence was detected in 64.4?% (76/118) and 88?% (103/117) patients in Group 1 and Group 2 with FDG-PET/CT, respectively. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of the FDG-PET/CT study for establishing recurrence were 100, 84, 89.4, 100 and 93.2?%, respectively, for Group 1; by contrast, these parameters were 97.1, 84.6, 98, 78.5 and 95.7?%, respectively, for Group 2. The number of patients with hepatic and extra-hepatic metastases, such as lung and abdominal lymph node metastasis, detected with FDG-PET/CT was significantly different in Group 1 than in Group 2; however, the number of patients with local recurrence and peritoneal implants detected with FDG-PET/CT was not different between the two groups.

Conclusions

FDG-PET/CT can accurately detect tumor recurrence in patients with suspected recurrent CRC, even for patients with normal CEA levels.     

Fluorine- 18-fluorodeoxyglucose positron emission tomography for assessment of patients with unresectable recurrent or metastatic lung cancers after CT-guided radiofrequency ablation: Preliminary results

OBJECTIVES: We compared the diagnostic value of fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) with that of computed tomography (CT) following radiofrequency ablation (RFA) of inoperable recurrent or metastatic cancers in the lung. METHODS: Twelve patients (9 males and 3 females; 5 had recurrent lung cancer and the other 7 had metastatic nodules from a variety of primary cancers) were treated by RFA for 17 pulmonary nodules. FDG-PET was performed before and 2 months after RFA, and the mean standardized uptake value (SUV) was calculated. The response evaluation was based on the percent reduction relative to the baseline and the absolute values of SUV on FDG-PET performed at 2 months after RFA. We compared the response evaluations made based on findings of FDG-PET and CT at 2 and > or =6 months (mean 10.2) after RFA. RESULTS: The percent reduction in uptake at 2 months was significantly lower in nodules considered progressive (69.6 +/- 18.6%) than nonprogressive disease (38.7 +/- 12.5%; p < 0.01) based on CT findings at > or =6 months after RFA. The absolute SUV at 2 months was significantly higher in nodules considered progressive (2.61 +/- 0.75) than nonprogressive disease (1.05 +/- 0.67; p < 0.01) based on CT findings at > or =6 months post-RFA. CONCLUSION: Although our pilot study comprised few cases of various histopathological types of cancers in the lung, the results suggest that FDG-PET could predict regrowth on subsequent follow-up CT. Regrowth could be diagnosed earlier by FDG-PET than by CT, and nodules with residual uptake and with <60% reduction of uptake relative to baseline on FDG-PET at 2 months after ablation might require additional therapy.     

Extranodal nasal NK/T cell lymphoma with bronchial mucoepidermoid carcinoma and lung adenocarcinoma: a case report

Extranodal nasal NK/Tcell lymphoma (ENKTCL) is a relatively rare type of non-Hodgkin''s lymphoma. It is highly malignant, highly invasive, and easy to relapse. Most patients have a poor prognosis. We report a 48-year-old woman who presented with irritant dry cough that had persisted for 6 m. CT showed a mass in the right nasal cavity, with uneven density similar to soft tissue, with slight uneven enhancement. The mass and the upper, middle, and lower turbinates were not clearly demarcated, involving multiple adjacent sinus cavities, and the local bone showed osteolytic destruction; MRI showed isosignal on T1WI and slightly hypersignal on T2WI and DWI. In addition, there was a mass of soft tissue density at the bronchial opening in the right middle lobe, showing uneven and obvious enhancement; a cavity was seen in the nodule of the right lower lobe, and the adjacent pleura was stretched, showing moderate enhancement. The nasal mass was diagnosed as extranodal NK/T cell lymphoma, the right middle lobe mass was diagnosed as mucoepidermoid carcinoma, and the right lower lobe mass was diagnosed as lung adenocarcinoma. ENKTCL rarely invades the lungs. If a patient has a lung occupying lesion similar to it, biopsy confirmation should be considered to avoid misdiagnosis as a chest metastasis that affects the treatment effect.     

Systemic Immune Response to Vaccination on FDG-PET/CT

A patient with newly diagnosed right lung cancer had transient ¹⁸F-fluorodeoxyglucose (FDG)-avid left axillary lymph nodes and intense splenic FDG uptake on positron emission tomography (PET)/computed tomography (CT). History revealed that the patient received a left-sided influenza vaccine 2–3 days before the examination. Although inflammatory FDG uptake in ipsilateral axillary nodes is reported, to our knowledge, this is the first report of visualization of the systemic immune response in the spleen related to the influenza vaccination on FDG-PET/CT. The history, splenic uptake and time course on serial FDG-PET/CT helped to avoid a false-positive interpretation for progressing lung cancer and alteration of the radiation therapy plan.     

食管结核的影像学诊断(附5例报告)

目的　探讨食管结核的影像学表现 ,提高对该病的认识。方法　回顾性分析 5例经病理证实的食管结核 ,男 2例 ,女 3例 ,年龄 2 4～ 3 6岁 ,平均 2 9岁。 5例均行食管钡剂造影、CT和电子纤维胃镜检查 ,1例行手术治疗。结果　食管钡剂造影示 :食管上段 1例 ,中段 3例 ,下段 1例 ,表现为充盈缺损 2例 ,向心性狭窄 2例 ,腔内点状钡斑 1例 ,腔外不规则窦道形成 1例。黏膜纹破坏2例 ,平坦或消失 3例。胸部CT平扫 :1例左肺下叶后基底段支气管扩张 ,右肺门增大 ,右胸壁有小结节 ;1例食管下段管壁不规则增厚 ;1例胸膜肥厚粘连 ;2例未见明显异常。术前影像学误诊 3例 ,正确诊断 2例。结论　食管结核缺乏影像学的特点 ,诊断应密切结合临床。     

Low-sensitivity FDG-PET studies: less common lung neoplasms

Computed tomography (CT) and positron emission tomography (PET) using the radiopharmaceutical 18F-2-deoxy-d-glucose (FDG) play an important role in the diagnosis and tumor node metastasis staging of patients with non-small cell lung cancer (NSCLC). CT is the optimal modality for evaluating the primary tumor, whereas PET is useful in improving the accuracy of staging by detecting occult nodal and distant metastases. However, both modalities have limitations in the evaluation of the primary tumor and in the detection of metastases. With regard to FDG-PET, these limitations are amplified in primary adenocarcinoma of the lung that manifests as a subsolid nodule and in primary carcinoid tumors of the lung, as these malignancies commonly have low levels of FDG avidity. Because the misinterpretation of CT and PET studies can alter the diagnosis and staging when evaluating subsolid nodules and carcinoid tumors, awareness and knowledge of these limitations are required for appropriate patient management. This article reviews the use of PET in patients with these uncommon lung neoplasms as well as radiotracers that have been developed to interrogate different metabolic pathways, receptors, and targets to overcome the potential limitations of FDG-PET in the diagnosis, staging, as well as early response evaluation and monitoring of response to targeted therapies.     

Fluor-18-fluorodeoxyglucose positron emission tomography (FDG-PET) in malignant melanoma. Diagnostic comparison with conventional imaging methods

Purpose: To assess the diagnostic value of fluor-18-fluorodeoxyglucose positron emission tomography (FDG-PET) in screening for melanoma metastases.Material and Methods: The case records of 94 melanoma patients who had been examined by whole-body FDG-PET between 1995 and 1999 were evaluated retrospectively. Forty patients showed evidence of lymphogenous and 42 of hematogenous metastasis. The maximal interval between PET and the diagnostic procedure under comparison was 2 weeks. Confirmation of the findings was based on histology or the clinical or radiological course.Results: In 24 patients, all diagnostic examinations including CT had been performed within 2 weeks from PET. In no case did PET change the staging. In 13 patients, PET agreed with morphological diagnosis in the number of metastatically invaded organs. This included 3 patients without metastases. The estimated number of organs invaded by metastases was higher with PET in 5 patients and higher with morphological imaging techniques in 6 patients. Among the PET findings with higher or equivocal counts of organs with metastases there were 2 confirmed false-positive findings.Conclusion: In a selected patient population, FDG-PET was found to be inferior to CT for diagnosing lung and liver metastases. The supplementary use of FDG-PET is not generally of value once metastasis has been established.     

Toward clinically usable CAD for lung cancer screening with computed tomography

Objectives

The purpose of this study was to define clinically appropriate, computer-aided lung nodule detection (CAD) requirements and protocols based on recent screening trials. In the following paper, we describe a CAD evaluation methodology based on a publically available, annotated computed tomography (CT) image data set, and demonstrate the evaluation of a new CAD system with the functionality and performance required for adoption in clinical practice.

Methods

A new automated lung nodule detection and measurement system was developed that incorporates intensity thresholding, a Euclidean Distance Transformation, and segmentation based on watersheds. System performance was evaluated against the Lung Imaging Database Consortium (LIDC) CT reference data set.

Results

The test set comprised thin-section CT scans from 108 LIDC subjects. The median (±IQR) sensitivity per subject was 100 (±37.5) for nodules?≥?4 mm and 100 (±8.33) for nodules?≥?8 mm. The corresponding false positive rates were 0 (±2.0) and 0 (±1.0), respectively. The concordance correlation coefficient between the CAD nodule diameter and the LIDC reference was 0.91, and for volume it was 0.90.

Conclusions

The new CAD system shows high nodule sensitivity with a low false positive rate. Automated volume measurements have strong agreement with the reference standard. Thus, it provides comprehensive, clinically-usable lung nodule detection and assessment functionality.

Key Points

? CAD requirements can be based on lung cancer screening trial results. ? CAD systems can be evaluated using publically available annotated CT image databases. ? A new CAD system was developed with a low false positive rate. ? The CAD system has reliable measurement tools needed for clinical use.     

FDG-PET/CT findings of autoimmune pancreatitis associated with idiopathic retroperitoneal fibrosis

We report the fluorodeoxyglucose positron emission tomography (FDG-PET)/computed tomography (CT) findings of autoimmune pancreatitis (AIP) associated with idiopathic retroperitoneal fibrosis. A 69-year-old male patient was admitted to our hospital with obstructive jaundice. Six months prior to this admission, he was treated with steroid therapy for retroperitoneal fibrosis. Laboratory data showed that elevated T-bil, C-reactive protein, amylase and immunoglobulin 4, and antinuclear antibodies were positive. Clinical history, laboratory data, CT image, and magnetic resonance imaging led to a diagnosis of autoimmune pancreatitis. To investigate the inflammatory activity, FDG-PET/CT was undertaken. FDG-PET/CT demonstrated diffuse intense FDG uptake in the enlarged pancreas and diffuse mild uptake in the region of the abdominal aorta-bilateral iliac arteries. A dilated right renal pelvis and upper ureter, corresponding to hydronephrosis probably caused by retroperitoneal fibrosis, were shown. An FDG-PET/CT was useful to evaluate inflammatory activity and morphological imaging, and supported our diagnosis of AIP and retroperitoneal fibrosis.     

Dual-modality FDG-PET/CT in follow-up of patients with recurrent iodine-negative differentiated thyroid cancer

The usefulness of combined 2-[¹⁸F] fluoro-2-deoxy-D-glucose positron emission tomography and computed tomography (FDG-PET/CT) in locating suspected recurrence in patients with iodine-negative differentiated thyroid cancer (DTC) was evaluated. Thirty-six patients with DTC and suspected iodine-negative recurrence underwent restaging with FDG-PET/CT. The images of CT, FDG-PET, both modalities viewed side by side (CT+PET), and FDG-PET/CT were evaluated by two physicians separately. Imaging results were correlated with either histology (n = 20) and/or clinical follow-up of at least 36 months. Recurrent disease was diagnosed in 22/36 patients. FDG-PET alone, CT alone, CT+PET, and FDG-PET/CT showed a sensitivity of 82%, 73%, 91%, and 96%, respectively. Specificities were 79%, 71%, 79%, and 100%, respectively. FDG-PET/CT significantly improved specificity compared with CT+PET and resulted in a further treatment modification in 5/36 patients (14%). CT alone was especially sensitive for lung metastases, FDG-PET alone for the remainder of the body. Accurate fusion of functional and morphologic data by FDG-PET/CT improves the staging accuracy of patients with suspected recurrence of iodine-negative DTC. This has an impact on patient management in a substantial number of patients.     

肺炎性结节30例CT分析

目的:探讨肺炎性结节的CT征象与鉴别诊断。方法:回顾性分析经手术及病理证实的肺炎性结节病例30例,其中单发28例,多发2例。共33个结节。结果:①病变部位:结节位于两肺下叶基底段15个,背段8个,上叶后段(尖后段)3个,前段1个;中叶(舌叶)6个,均邻近胸膜。②CT征象:病灶呈类圆形30个,不规则形3个。其中密度均匀26个,支气管充气征5个,空洞2个,边缘光整16例,有粗长毛刺8例,边缘模糊似短毛刺或棘状突起5例,分叶4例,垂直于胸膜的刀切样边缘13例,局部胸膜增厚粘连18例,胸膜尾征16例。结论:全面分析CT征象能提高肺炎性结节的正确诊断率。     

FDG PET/CT allowing detection and follow-up of tumor cell transplantation

After detection of small cell lung cancer in a 67-year-old patient who had donated a kidney 7 months earlier, the graft recipient underwent FDG-PET/CT to determine the presence/absence of tumor cell transmission. It showed abnormal increased uptake of the renal graft, associated with hypermetabolic lymph nodes and hepatic, pulmonary and bone lesions. Emergency graft resection was performed 5 days after PET/CT, permitting immunosuppressive therapy withdrawal. Pathologic examination of the kidney showed parenchymal infiltration by tumor cells compatible with small cell lung cancer. Thereafter, pathologists proved that the recipient’s and donor’s tumor cells matched using microsatellite markers. FDG-PET/CT was performed in the follow-up and showed progression in the donor despite chemotherapy and radiotherapy. He died a few months later. However, FDG-PET/CT showed a complete metabolic response after only 3 courses of chemotherapy in the recipient.     

CT引导建立兔肺VX2肿瘤模型的实验研究

目的 建立适合微波消融的兔肺肿瘤模型.方法 新西兰大白兔36只,CT引导下穿刺,将载有VX2肿瘤组织悬液的亲水凝胶接种于右肺内.结果 接种后14～26 d,CT检查证实34只新西兰大白兔肺内有肿瘤生长,其中26只呈单发结节,直径0.5～0.8 cm,兔肺VX2肿瘤模型成功率为72.2%(26/36);另有2只肺内呈多发结节生长,并出现胸腔积液;4只累及纵隔;2只出现胸壁种植转移.接种过程未出现气胸、出血等并发症.结论 本实验建模方法安全、有效,并可在肺内局部形成较大体积的实体瘤,能满足微波消融治疗肺癌的研究需要,因此所建兔肺VX2肿瘤模型是成功的.