Clinical value of <Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography in patients with connective tissue disease

Connective tissue diseases represent a heterogeneous group of immunologically mediated inflammatory disorders with a large variety of affected organs other than the lung. ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) is widely used in oncology but may also be valuable in patients with infections or inflammatory disease. The purpose of this article was to assess the clinical value of ¹⁸F-FDG PET in patients with connective tissue disease. Our experience demonstrates that ¹⁸F-FDG PET is a unique imaging technique for assessing the metabolic activity throughout the body in those with a connective tissue disease. The technique appears to be a promising imaging modality for detecting coexistent neoplastic diseases and other autoimmune disorders.     

<Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography in uterine carcinosarcoma

Purpose Uterine carcinosarcomas clinically confined to the uterus usually harbor occult metastases. We conducted a pilot study to evaluate the value of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in uterine carcinosarcoma. Methods Patients with histologically confirmed uterine carcinosarcoma were enrolled. Abdominal and pelvic magnetic resonance imaging (MRI)/whole-body computed tomography (CT) scan, and whole-body ¹⁸F-FDG PET or PET/CT were undertaken for primary staging, evaluating response, and restaging/post-therapy surveillance. The clinical impact of ¹⁸F-FDG PET was determined on a scan basis. Results A total of 19 patients were recruited and 31 ¹⁸F-FDG PET scans (including 8 scans performed on a PET/CT scanner) were performed. Positive impacts of scans were found in 36.8% (7/19) for primary staging, 66.7% (2/3) for monitoring response, and 11.1% (1/9) for restaging/post-therapy surveillance. PET excluded falsely inoperable disease defined by MRI in two patients. Aggressive treatment applying to three patients with PET-defined resectable stage IVB disease seemed futile. Two patients died of disease shortly after salvage therapy restaged by PET. With PET monitoring, one stage IVB patient treated by targeted therapy only was alive with good performance. Using PET did not lead to improvement of overall survival of this series compared with the historical control (n = 35) (P = 0.779). Conclusions The preliminary results suggest that ¹⁸F-FDG PET is beneficial in excluding falsely inoperable disease for curative therapy and in making a decision on palliation for better quality of life instead of aggressive treatment under the guidance of PET. PET seems to have limited value in post-therapy surveillance or restaging after failure.     

Role of <Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography/computed tomography for therapy evaluation of patients with large-vessel vasculitis

Purpose  

Systemic vasculitis is a multisystem disease characterized by inflammation of blood vessels. Diagnosing extension of the disease and evaluating the response to therapy are cornerstones in the clinical management of vasculitis, and imaging has a pivotal role in this field.     

The performance of<Superscript> 18</Superscript>F-fluorodeoxyglucose positron emission tomography in small solitary pulmonary nodules

Solitary pulmonary nodule (SPN, intraparenchymal lung mass <3 cm) is often a diagnostic challenge. This study was performed to evaluate the diagnostic accuracy of ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG PET) in radiologically indeterminate SPN 10 mm on spiral CT. Between August 1997 and March 2001, we identified all patients with radiologically indeterminate SPNs 10 mm who were referred for FDG PET imaging at the VU University Medical Centre. All PET scans were retrospectively reviewed by an experienced nuclear medicine physician. PET was considered positive in cases with at least moderately enhanced focal uptake, and otherwise as negative. Lesions were considered benign on the basis of histology, no growth during 1.5 years or disappearance within at least 6 months. Thirty-five patients with 36 SPNs 10 mm in diameter at clinical presentation were identified (one patient had two metachronous lesions). In 13 of 14 malignant nodules and in two of 22 benign nodules, diagnosis was confirmed by histology. Prevalence of malignancy was 39%. PET imaging correctly identified 30 of 36 small lesions. One lesion proved to be false negative on PET (CT: 10 mm), and in five lesions, PET scans proved to be false positive. Specificity was 77% (17/22; 95% CI: 0.55–0.92), sensitivity 93% (13/14; 95% CI: 0.66–1.0), positive predictive value 72% (13/18; 95% CI: 0.46–0.90) and negative predictive value 94% (17/18; 95% CI: 0.73–1.0). This retrospective study suggests that FDG PET imaging could be a useful tool in differentiating benign from malignant SPNs 10 mm in diameter at clinical presentation. Such results may help in the design of larger prospective trials with structured clinical work-up.     

Textural features of <Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography scanning in diagnosing aortic prosthetic graft infection

Background

The clinical problem in suspected aortoiliac graft infection (AGI) is to obtain proof of infection. Although ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography scanning (PET) has been suggested to play a pivotal role, an evidence-based interpretation is lacking. The objective of this retrospective study was to examine the feasibility and utility of ¹⁸F-FDG uptake heterogeneity characterized by textural features to diagnose AGI.

Methods

Thirty patients with a history of aortic graft reconstruction who underwent ¹⁸F-FDG PET/CT scanning were included. Sixteen patients were suspected to have an AGI (group I). AGI was considered proven only in the case of a positive bacterial culture. Positive cultures were found in 10 of the 16 patients (group Ia), and in the other six patients, cultures remained negative (group Ib). A control group was formed of 14 patients undergoing ¹⁸F-FDG PET for other reasons (group II). PET images were assessed using conventional maximal standardized uptake value (SUVmax), tissue-to-background ratio (TBR), and visual grading scale (VGS). Additionally, 64 different ¹⁸F-FDG PET based textural features were applied to characterize ¹⁸F-FDG uptake heterogeneity. To select candidate predictors, univariable logistic regression analysis was performed (α?=?0.16). The accuracy was satisfactory in case of an AUC?>?0.8.

Results

The feature selection process yielded the textural features named variance (AUC?=?0.88), high grey level zone emphasis (AUC?=?0.87), small zone low grey level emphasis (AUC?=?0.80), and small zone high grey level emphasis (AUC?=?0.81) most optimal for distinguishing between groups I and II. SUVmax, TBR, and VGS were also able to distinguish between these groups with AUCs of 0.87, 0.78, and 0.90, respectively. The textural feature named short run high grey level emphasis was able to distinguish group Ia from Ib (AUC?=?0.83), while for the same task the TBR and VGS were not found to be predictive. SUVmax was found predictive in distinguishing these groups, but showed an unsatisfactory accuracy (AUC?=?0.75).

Conclusion

Textural analysis to characterize ¹⁸F-FDG uptake heterogeneity is feasible and shows promising results in diagnosing AGI, but requires additional external validation and refinement before it can be implemented in the clinical decision-making process.

     

<Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography-computed tomography in the management of adult multisystem Langerhans cell histiocytosis

Purpose

The standard evaluation of multisystem Langerhans cell histiocytosis (LCH) includes a clinical evaluation, laboratory tests and a skeleton/skull X-ray survey, with chest high-resolution computed tomography (HRCT) in the case of pulmonary involvement. Preliminary reports suggest that ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸F-FDG PET-CT) may be useful for evaluating patients with LCH.

Methods

Fourteen consecutive adult patients with multisystem LCH were included in this retrospective study, and were evaluated using standard procedures and ¹⁸F-FDG PET-CT. The two sets of findings were compared both at baseline and during follow-up. Serial HRCT and pulmonary function tests were used to evaluate outcome in patients with lung involvement.

Results

At the baseline evaluation, PET-CT identified every LCH localization found with the standard evaluation (except a mild cecum infiltration). PET-CT showed additional lesions in seven patients, mostly involving bones, and differentiated inactive from active lesions. Thyroid ¹⁸F-FDG uptake was identified in three cases. No pituitary stalk ¹⁸F-FDG uptake was observed in patients with pituitary LCH. Only 3/12 (25 %) patients with pulmonary LCH displayed moderate pulmonary ¹⁸F-FDG uptake. During follow-up, variations (≥50 % of maximum standardized uptake) in bone ¹⁸F-FDG uptake intensity were correlated with disease state and response to treatment. The absence of lung ¹⁸F-FDG uptake did not preclude lung function improvement after treatment.

Conclusions

Except for cases with pulmonary and pituitary involvement, ¹⁸F-FDG PET-CT could replace the standard evaluation for staging of adult patients with multisystem LCH. Serial PET-CT scans are useful for evaluating treatment responses, particularly in cases with bone LCH involvement.

     

Prognostic value of <Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography/computed tomography in patients with Barcelona Clinic Liver Cancer stages 0 and A hepatocellular carcinomas: a multicenter retrospective cohort study

Purpose

We evaluated the prognostic value of pretreatment ¹⁸F-fluorodeoxyglucose positron emission tomography with computed tomography (FDG PET/CT) in patients with Barcelona Clinic Liver Cancer (BCLC) stage 0 or A hepatocellular carcinoma (HCC) who had received curative treatment or transarterial chemoembolization (TACE).

Methods

Between 2009 and 2010, 317 patients diagnosed with HCC at seven hospitals were enrolled. Among these, 195 patients underwent curative treatments including resection, liver transplantation, and radiofrequency ablation. TACE was performed in 122 patients. The tumor-to-normal liver standardized uptake value ratio (TLR) of the primary tumor was measured using pretreatment FDG PET/CT. The prognostic significance of TLR and other clinical variables was assessed using Cox regression models. Differences in the overall survival (OS) associated with TLR or other significant clinical factors were examined using the Kaplan-Meier method.

Results

Over a median follow-up period of 46 months, 77 patients died from cancer. In the curative cohort, higher TLR (≥2) was significantly associated with death (hazard ratio [HR]?=?2.68; 95 % CI, 1.16–6.15; P?=?0.020) in multivariable analysis. Patients with a higher TLR had significantly worse OS than patients with a lower TLR (5-year overall survival, 61 % vs. 79.4 %; P?=?0.006). In the TACE cohort, the Model for End-Stage Liver Disease (MELD) score (≥8) was a significant independent prognostic factor for OS (HR?=?3.34; 95 % CI, 1.49–7.48; P?=?0.003), whereas TLR was not associated with OS. The Kaplan-Meier curves showed significantly poorer OS in patients with higher MELD scores (≥8) than in those with lower MELD scores (5-year survival rate, 33.1 % vs. 79.6 %; P?<?0.001).

Conclusions

Pretreatment TLR measured using FDG PET/CT was an independent prognostic factor for OS in patients with BCLC stage 0 or A HCC undergoing curative treatment. In contrast, underlying liver function appeared to be important in predicting the prognosis of patients undergoing TACE.

     

Plurifocal malignant peripheral nerve sheath tumor demonstrated by <Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography/computed tomography

Malignant peripheral nerve sheath tumors (MPNSTs) are sarcomas that derive from peripheral nerves or from cells associated with the nerve sheath. Magnetic resonance imaging is the main diagnostic imaging modality for evaluating MPNSTs. Computed tomography (CT) of the chest is the main imaging modality used to screen for distant disease, and bone scanning is considered useful for identifying selected metastases. Fluorodeoxyglucose positron emission tomography (FDG-PET) has been useful for differentiating malignant nerve sheath tumors from benign lesions and appears to be able to forecast prognosis. We report a case of a patient with neurofibromatosis 1 (NF1) with a histological diagnosis of MPNST, which was diagnosed by biopsy of a posterior right thigh mass examined by ¹⁸F-FDG-PET/CT.     

Intestinal metastasis from non-small-cell lung cancer initially detected by <Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography

Gastrointestinal (GI) metastasis from non-small-cell lung cancer (NSCLC) is relatively rare. As most patients with GI metastasis are diagnosed on the occasion of serious complications, such as ileus or perforation, the appropriate diagnosis is important. Here, we report a case of NSCLC metastatic to the small intestine diagnosed at initial staging using ¹⁸F-fluorodeoxyglucose positron emission tomography.     

Value of <Superscript>18</Superscript>F-fluorodeoxyglucose uptake in positron emission tomography/computed tomography in predicting survival in multiple myeloma

Purpose  

We assessed the role of the maximum standardized uptake value (SUV_max) of bone marrow and the extramedullary lesion with the highest SUV_max in positron emission tomography/computed tomography (PET/CT) of newly diagnosed multiple myeloma (MM) patients in predicting overall survival (OS).     

False-positive <Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography/computed tomography caused by incidental injury in a bulky intracystic carcinoma of the breast

We present a case of right intracystic carcinoma of the breast. An 83-year-old woman was seen at our hospital with a growing bulky mass in the right breast for the last 2 years. Whole-body fluorine-18 fluorodeoxyglucose positron emission tomography and computed tomography (¹⁸F-FDG-PET/CT) was performed 15 days after mammography (MMG). ¹⁸F-FDGPET/CT showed a right bulky cystic mass and intense FDG uptake in the intracystic nodules as well as in the adjacent extracystic lesion and the underlying pectoralis major muscle. It suggested tumor invasion of the pectoralis major muscle. Right mastectomy combined with partial resection of adherent pectoral muscle was performed. The main cystic lesion was diagnosed to be solid-papillary carcinoma, but the area of the pectoralis muscle was diagnosed to be a “foreign body” inflammation. It was thought that the compression related to MMG and core needle biopsy induced an injury in the bulky breast mass with leakage of contents into adjacent tissue, resulting in the foreign body inflammation. In conclusion, the coexisting foreign body inflammation was responsible for a false-positive ¹⁸F-FDG-PET/CT scan in the current case.     

Usefulness of <Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography for diagnosing disease activity and monitoring therapeutic response in patients with pulmonary mycobacteriosis

Purpose  To evaluate the usefulness of ¹⁸F-FDG PET in the imaging of pulmonary lesions related to disease activity and in monitoring responses to treatment in patients with pulmonary mycobacteriosis (PM). Materials and methods  We used high-resolution computed tomography (HRCT) and ¹⁸F-FDG PET to evaluate 47 consecutive untreated patients with PM, 25 with tuberculosis (TB) and 22 with Mycobacterium avium-intracellulare complex (MAC), who presented with small peripheral pulmonary nodules ≤3 cm, and compared the findings. The diagnosis of mycobacteriosis was confirmed by bacteriological examinations of bronchoscopic or surgically resected specimens. PET scans were visually and quantitatively analysed using SUVmax. In addition, 14 patients with PM underwent repeat PET scanning during antimycobacterial therapy, and changes in ¹⁸F-FDG uptake were clinically evaluated (6 during treatment and 12 after treatment). Results  Of all the lesions, 87.2% had SUVmax levels ranging from 3 to 7 (5.05 ± 1.56, range 2.5–7.6, n = 47). Further, SUV levels in patients with PM reflected disease activity as estimated by HRCT, but did not differ significantly between those with TB (4.96 ± 1.61, n = 25) and MAC (5.15 ± 1.53, n = 22). ¹⁸F-FDG uptake was significantly decreased in all 14 patients who received chemotherapy, indicating a positive response to treatment. Conclusion   ¹⁸F-FDG PET is considered to be useful for the diagnosis and evaluation of disease activity along with HRCT findings, and in monitoring response to chemotherapy in patients with PM.     

Application of <Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography to detection of proximal lesions of obstructive colorectal cancer

Purpose  

In cases of obstructive colorectal cancer (CRC), preoperative diagnosis of the proximal lesion is often difficult when the primary lesion impedes the passage of the endoscope. The aim of this study was to evaluate the usefulness of fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) in such cases.     

Constrictive tuberculous pericarditis diagnosed using <Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography: a report of two cases

We present two cases of tuberculous pericarditis that were diagnosed using ¹⁸F-fluorodeoxyglycose (¹⁸F-FDG) positron emission tomography (PET). Here, we highlight the value of ¹⁸F-FDG-PET for demonstrating tuberculous pericardial involvement as well as disease dissemination and activity. The patients received antitubercular treatment, and their symptoms and findings resolved accordingly.     

<Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography in the diagnosis of malignancy in patients with paraneoplastic neurological syndrome: a systematic review and meta-analysis

Purpose

The detection of occult cancer in patients suspected of having a paraneoplastic neurological syndrome (PNS) poses a diagnostic challenge. The aim of our study was to perform a systematic review and meta-analysis to assess the diagnostic performance of FDG PET for the detection of occult malignant disease responsible for PNS.

Methods

A systematic review of the literature (MEDLINE, EMBASE, Cochrane, and DARE) was undertaken to identify studies published in any language. The search strategy was structured after addressing clinical questions regarding the validity or usefulness of the test, following the PICO framework. Inclusion criteria were studies involving patients with PNS in whom FDG PET was performed to detect malignancy, and which reported sufficient primary data to allow calculation of diagnostic accuracy parameters. When possible, a meta-analysis was performed to calculate the joint sensitivity, specificity, and detection rate for malignancy (with 95% confidence intervals [CIs]), as well as a subgroup analysis based on patient characteristics (antibodies, syndrome).

Results

The comprehensive literature search revealed 700 references. Sixteen studies met the inclusion criteria and were ultimately selected. Most of the studies were retrospective (12/16). For the quality assessment, the QUADAS-2 tool was applied to assess the risk of bias. Across 16 studies (793 patients), the joint sensitivity, specificity, and detection rate for malignancy with FDG PET were 0.87 (95% CI: 0.80–0.93), 0.86 (95% CI: 0.83–0.89), and 14.9% (95% CI: 11.5–18.7), respectively. The area under the curve (AUC) of the summary ROC curve was 0.917. Homogeneity of results was observed for sensitivity but not for specificity. Some of the individual studies showed large 95% CIs as a result of small sample size.

Conclusions

The results of our meta-analysis reveal high diagnostic performance of FDG PET in the detection of malignancy responsible for PNS, not affected by the presence of onconeural antibodies or clinical characteristics.

     

Pulmonary artery intimal sarcoma: the role of <Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography in monitoring response to treatment

We report the case of 58-year-old man with pulmonary artery intimal sarcoma. He initially presented with cough, right-sided chest pain, and shortness of breath. Although the diagnosis of pulmonary embolism had been considered, chest radiograph and pulmonary perfusion scintigraphy showed a mass in the right hilum and no perfusion in the right lung. ¹⁸F-fluorodeoxyglucose positron emission computed tomography (FDGPET) showed increased FDG uptake in the mass obstructing the right pulmonary artery. Fine-needle biopsy revealed a pathological diagnosis of pulmonary artery intimal sarcoma. The patient was successfully treated with radiotherapy and adjuvant chemotherapy. FDG-PET was used for monitoring the response to therapy.     

18F-氟脱氧葡萄糖PET在原发性肝细胞癌中的应用

肝细胞癌(HCC)的早期诊断是获得临床治愈的关键,准确分期是制定合理治疗方案的基础.尽管18F-氟脱氧葡萄糖(18F-FDG)PET诊断HCC的总体敏感性不高,但其阳性显像与肿瘤分化程度、肝内外转移、门静脉癌栓及血清甲胎蛋白水平等许多因素相关.因此,18F-FDG PET在中、低分化的HCC诊断、分期与再分期、监测治疗反应、评价疗效、判断预后以及鉴别肝脏良性疾病等方面具有独特的价值.     

Role of <Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography/computed tomography in patients affected by differentiated thyroid carcinoma,high thyroglobulin level,and negative <Superscript>131</Superscript>I scan: review of the literature

Differentiated thyroid carcinoma (DTC) is a slow-growing tumor that represents 1% of all malignant tumors and is the most frequent endocrine cancer. ¹⁸F-Fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) imaging is an increasingly important imaging tool in oncology and is still under investigation in numerous studies looking into its efficacy and cost-effectiveness. Despite the fact that ¹⁸F-FDG-PET/CT has been shown to be a powerful and accurate diagnostic tool in patients affected by DTC with high serum thyroglobulin (Tg) levels and negative radioiodine (¹³¹I) total body scan, its definitive role is not completely clear, in particular regarding the role of thyroid stimulating hormone (TSH) and Tg value “cutoff” over which is better to perform the study. In this review, these issues are analyzed to clarify controversial aspects and identify established cornerstones. In particular, the literature analysis suggests that levothyroxine withdrawal is preferable in cases of relatively low Tg levels (<10 ng/ml) and good clinical compliance to hypothyroidism. Moreover, recombinant thyrotropin stimulating hor mone (rTSH) could be a preferable alternative in patients clinically unable to tolerate therapy withdrawal. A Tg cutoff level over which to perform the study seems to be 10 ng/ml, a reasonable value maintaining high accuracy in terms of a good compromise between sensitivity and specificity.     

Diagnostic accuracy of <Superscript>18</Superscript>F-fluorodeoxyglucose positron emission tomography/computed tomography in differentiated thyroid cancer patients with elevated thyroglobulin and negative <Superscript>131</Superscript>I whole body scan: evaluation by thyroglobulin level

Background  

To evaluate the diagnostic accuracy of ¹⁸F-FDG PET/CT in detection of recurrent differentiated thyroid cancer (DTC) in patients with elevated stimulated thyroglobulin (Tg) or anti-Tg antibody (Ab) levels, and negative ¹³¹I whole body scan according to the Tg level.     

<Superscript>18</Superscript>F-DOPA positron emission tomography for the detection of glomus tumours

The purpose of this study was to evaluate (18)F-DOPA whole-body positron emission tomography ((18)F-DOPA PET) as a biochemical imaging approach for the detection of glomus tumours. (18)F-DOPA PET and magnetic resonance imaging (MRI) were performed in ten consecutive patients with proven mutations of the succinate dehydrogenase subunit D ( SDHD) gene predisposing to the development of glomus tumours and other paragangliomas. (18)F-DOPA PET and MRI were performed according to standard protocols. Both methods were assessed under blinded conditions by two experienced specialists in nuclear medicine (PET) and diagnostic radiology (MRI). Afterwards the results were compared. A total of 15 lesions (four solitary and four multifocal tumours, the latter including 11 lesions) were detected by (18)F-DOPA PET. Under blinded conditions, (18)F-DOPA PET and MRI revealed full agreement in seven patients, partial agreement in two and complete disagreement in one. Eleven of the 15 presumed tumours diagnosed by (18)F-DOPA PET were confirmed by MRI. The correlation of (18)F-DOPA PET and MRI confirmed three further lesions previously only detected by PET. All of them were smaller than 1 cm and had the signal characteristics of lymph nodes. For one small lesion diagnosed by PET, no morphological MRI correlate could be found even retrospectively. No tumour was detected by MRI that was negative on (18)F-DOPA PET. All tumours diagnosed by MRI showed a hyperintense signal on T2-weighted images and a distinct enhancement of contrast medium on T1-weighted images. The mean tumour size was 1.5+/-0.5 cm. (18)F-DOPA PET seems to be a highly sensitive metabolic imaging procedure for the detection of glomus tumours and may have potential as a screening method for glomus tumours in patients with SDHD gene mutations.