Impact of fluorodeoxyglucose PET on the management of esophageal cancer

Application of partial volume effect correction and 4D PET in the quantification of FDG avid lung lesions

PURPOSE

The aim of this study is to assess a software-based method with semiautomated correction for partial volume effect (PVE) to quantify the metabolic activity of pulmonary malignancies in patients who underwent non-gated and respiratory-gated 2-deoxy-2-[(18)F]fluoro-D-glucose (FDG)-positron emission tomography (PET)/x-ray computed tomography(CT).

PROCEDURES

The study included 106 lesions of 55 lung cancer patients who underwent respiratory-gated FDG-PET/CT for radiation therapy treatment planning. Volumetric PET/CT parameters were determined by using 4D PET/CT and non-gated PET/CT images. We used a semiautomated program employing an adaptive contrast-oriented thresholding algorithm for lesion delineation as well as a lesion-based partial volume effect correction algorithm. We compared respiratory-gated parameters with non-gated parameters by using pairwise comparison and interclass correlation coefficient assessment. In a multivariable regression analysis, we also examined factors, which can affect quantification accuracy, including the size of lesion and the location of tumor.

RESULTS

This study showed that quantification of volumetric parameters of 4D PET/CT images using an adaptive contrast-oriented thresholding algorithm and 3D lesion-based partial volume correction is feasible. We observed slight increase in FDG uptake by using PET/CT volumetric parameters in comparison of highest respiratory-gated values with non-gated values. After correction for partial volume effect, the mean standardized uptake value (SUVmean) and total lesion glycolysis (TLG) increased substantially (p value <0.001). However, we did not observe a clinically significant difference between partial volume corrected parameters of respiratory-gated and non-gated PET/CT scans. Regression analysis showed that tumor volume was the main predictor of quantification inaccuracy caused by partial volume effect.

CONCLUSIONS

Based on this study, assessment of volumetric PET/CT parameters and partial volume effect correction for accurate quantification of lung malignant lesions by using respiratory non-gated PET images are feasible and it is comparable to gated measurements. Partial volume correction increased both the respiratory-gated and non-gated values significantly and appears to be the dominant source of quantification error of lung lesions.

Medical imaging in personalised medicine: a white paper of the research committee of the European Society of Radiology (ESR)

The future of medicine lies in early diagnosis and individually tailored treatments, a concept that has been designated 'personalised medicine' (PM), which aims to deliver the right treatment to the right patient at the right time. Medical imaging has always been personalised and is fundamental to almost all aspects of PM. It is instrumental in solving clinical differential diagnoses. Imaging procedures are tailored to the clinical problem and patient characteristics. Screening for preclinical disease is done with imaging. Stratification based on imaging biomarkers can help identify individuals suited for preventive intervention. Treatment decisions are based on the in vivo visualisation of the location and extent of an abnormality, as well as the loco-regional physiological, biochemical and biological processes using structural and molecular imaging. Image-guided biopsy provides relevant tissue specimens for genetic/molecular characterisation. In addition, radiogenomics relate imaging biomarkers to these genetic and molecular features. Furthermore, imaging is essential to patient-tailored therapy planning, therapy monitoring and follow-up of disease, as well as targeting non-invasive or minimally invasive treatments, especially with the rise of theranostics. Radiologists need to be prepared for this new paradigm as it will mean changes in training, clinical practice and in research. Key Points • Medical imaging is a key component in personalised medicine • Personalised prevention will rely on image-based screening programmes • Anatomical, functional and molecular imaging biomarkers affect decisions on the type and intensity of treatment • Treatment response assessment with imaging will improve personalised treatment • Image-based invasive intervention integrates personalised diagnosis and personalised treatment.

Quantitative assessment of global lung inflammation following radiation therapy using FDG PET/CT: a pilot study

PURPOSE

Radiation pneumonitis is the most severe dose-limiting complication in patients receiving thoracic radiation therapy. The aim of this study was to quantify global lung inflammation following radiation therapy using FDG PET/CT.

METHODS

We studied 20 subjects with stage III non-small-cell lung carcinoma who had undergone FDG PET/CT imaging before and after radiation therapy. On all PET/CT studies, the sectional lung volume (sLV) of each lung was calculated from each slice by multiplying the lung area by slice thickness. The sectional lung glycolysis (sLG) was calculated by multiplying the sLV and the lung sectional mean standardized uptake value (sSUVmean) on each slice passing through the lung. The lung volume (LV) was calculated by adding all sLVs from the lung, and the global lung glycolysis (GLG) was calculated by adding all sLGs from the lung. Finally, the lung SUVmean was calculated by dividing the GLG by the LV. The amount of inflammation in the lung parenchyma directly receiving radiation therapy was calculated by subtracting tumor measurements from GLG.

RESULTS

In the lung directly receiving radiation therapy, the lung parenchyma SUVmean and global lung parenchymal glycolysis were significantly increased following therapy. In the contralateral lung (internal control), no significant changes were observed in lung SUVmean or GLG following radiation therapy.

CONCLUSION

Global lung parenchymal glycolysis and lung parenchymal SUVmean may serve as potentially useful biomarkers to quantify lung inflammation on FDG PET/CT following thoracic radiation therapy.

Advantages of positron emission tomography-computed tomography imaging in esophageal squamous cell carcinoma

To explore the value of positron emission tomography-computed tomography (PET-CT) scan in esophageal squamous cell carcinoma (ESCC), we retrospectively summarize the results of PET-CT scan from 118 patients, with ESCC who underwent PET-CT scan in the different courses during treatment. Then, the results of PET-CT scan plus other conventional methods were analyzed to identify the value of PET-CT scan in diagnosis, staging, response evaluation, monitoring recurrence, and metastasis following treatment. It is suggested that PET-CT scan possess high value in diagnosis and gives more favorable indication in N and M staging. PET-CT scan should be translated into routine surveillance for postoperation follow up and is one of more helpful evaluators of response to chemoradiotherapy or chemotherapy.

Outcomes of endoscopic and surgical resection for a second primary cancer in the residual cervical esophagus after thoracic esophagectomy

Patients who have received subtotal esophagectomy for thoracic esophageal cancer must be closely monitored for second primary malignancies. The purpose of this study is to review and assess patients who developed a second primary esophageal cancer in the residual cervical esophagus. Between 1996 and 2010, 10 patients were diagnosed in our hospital with esophageal squamous cell cancer in the residual cervical esophagus after undergoing thoracic esophagectomy and were treated with endoscopic or surgical resection. Data from these patients were reviewed retrospectively. Seven of the 10 patients (70%) had multiple primary carcinoma lesions at the time of their esophagectomy. A second primary cancer in the residual cervical esophagus was detected in eight patients during follow-up endoscopic examinations while the patients were still asymptomatic. Seven of the patients underwent endoscopic resection for a superficial cancer. None of those patients experienced any complications, and all are currently alive and cancer-free. The remaining three patients underwent resection of the cervical esophagus with regional lymph node dissection. Two of those patients experienced severe complications; one subsequently died (hospital death) from pneumonia, 12 months after surgery, while the other died from recurrence of his cancer. The third patient is alive and cancer-free. Early detection of a second primary malignancy in the residual cervical esophagus followed by endoscopic resection is the best treatment strategy for patients who previously received subtotal esophagectomy for thoracic esophageal cancer. Surgical resection puts patients at high risk of mortality or morbidity.

False positive diagnosis of metastatic esophageal carcinoma on positron emission tomography: a case report of cholecystitis simulating a hepatic lesion

Esophageal cancer has been increasing in incidence for the last several decades. The current staging evaluation includes computed tomography, endoscopic ultrasonography, and F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT), which influences the treatment options. PET/CT is limited in its ability to differentiate hypermetabolic metastatic disease from acute/chronic inflammatory conditions, and this must be considered during interpretation. This is the case report of a 77-year-old man with esophageal cancer whose PET/CT demonstrated increased F-18 FDG uptake in the right lobe of the liver. This was originally interpreted at an outside institution as suspicious for metastatic disease, which would have precluded potential surgical cure. Subsequent reinterpretation and additional imaging including magnetic resonance imaging suggested that the uptake in the liver was likely due to adjacent gallbladder inflammation. On the basis of this interpretation, an abdominal exploration, liver biopsy, cholecystectomy, and transhiatal esophagectomy were performed. Final pathology of the gallbladder revealed perforated cholecystitis and a pericholecystic abscess (related to a prior septic episode), which were responsible for the increased radiotracer uptake. This case is presented to illustrate the importance of considering benign etiologies that may mimic metastatic disease when interpreting PET/CT scans.