Lalitha K. Shankar

Purpose:Currently, guidelines for PET with 18F-fluorodeoxyglucose (FDG-PET) interpretation for assessment of therapy response in oncology primarily involve visual evaluation of FDG-PET/CT scans. However, quantitative measurements of the metabolic activity in tumors may be even more useful in evaluating response to treatment. Guidelines based on such measurements, including the European Organization for Research and Treatment of Cancer Criteria and PET Response Criteria in Solid Tumors, have been proposed. However, more rigorous analysis of response criteria based on FDG-PET measurements is needed to adopt regular use in practice.Experimental Design:Well-defined boundaries of repeatability and reproducibility of quantitative measurements to discriminate noise from true signal changes are a needed initial step. An extension of the meta-analysis from de Langen and colleagues (2012) of the test–retest repeatability of quantitative FDG-PET measurements, including mean, maximum, and peak standardized uptake values (SUVmax, SUVmean, and SUVpeak, respectively), was performed. Data from 11 studies in the literature were used to estimate the relationship between the variance in test–retest measurements with uptake level and various study-level, patient-level, and lesion-level characteristics.Results:Test–retest repeatability of percentage fluctuations for all three types of SUV measurement (max, mean, and peak) improved with higher FDG uptake levels. Repeatability in all three SUV measurements varied for different lesion locations. Worse repeatability in SUVmean was also associated with higher tumor volumes.Conclusions:On the basis of these results, recommendations regarding SUV measurements for assessing minimal detectable changes based on repeatability and reproducibility are proposed. These should be applied to differentiate between response categories for a future set of FDG-PET–based criteria that assess clinically significant changes in tumor response.

According to the World Health Organization, there were almost 18 million patients living with cancer in 2020. It is estimated that over 14 million patients will require oncologic surgery in 2040. This is a 52% increase from 2018 estimations.¹ Due to the importance of a complete (R0) resection on survival and the increase in detection of early-stage disease, surgical resection remains an important treatment of solid tumors.^2,3 Achieving an R0 resection and identifying disease in lymph nodes or synchronous lesions has been shown repeatedly to improve oncologic outcomes and is a mainstay of curative-intent treatment.⁴ However, achieving these margins and finding residual disease during surgery remains a challenge for surgical oncologists. This is mainly due to the inability to see microscopic disease left behind and, at times, uncertainty about involvement of vital structures.

Purpose:Currently, guidelines for PET with 18F-fluorodeoxyglucose (FDG-PET) interpretation for assessment of therapy response in oncology primarily involve visual evaluation of FDG-PET/CT scans. However, quantitative measurements of the metabolic activity in tumors may be even more useful in evaluating response to treatment. Guidelines based on such measurements, including the European Organization for Research and Treatment of Cancer Criteria and PET Response Criteria in Solid Tumors, have been proposed. However, more rigorous analysis of response criteria based on FDG-PET measurements is needed to adopt regular use in practice.Experimental Design:Well-defined boundaries of repeatability and reproducibility of quantitative measurements to discriminate noise from true signal changes are a needed initial step. An extension of the meta-analysis from de Langen and colleagues (2012) of the test–retest repeatability of quantitative FDG-PET measurements, including mean, maximum, and peak standardized uptake values (SUVmax, SUVmean, and SUVpeak, respectively), was performed. Data from 11 studies in the literature were used to estimate the relationship between the variance in test–retest measurements with uptake level and various study-level, patient-level, and lesion-level characteristics.Results:Test–retest repeatability of percentage fluctuations for all three types of SUV measurement (max, mean, and peak) improved with higher FDG uptake levels. Repeatability in all three SUV measurements varied for different lesion locations. Worse repeatability in SUVmean was also associated with higher tumor volumes.Conclusions:On the basis of these results, recommendations regarding SUV measurements for assessing minimal detectable changes based on repeatability and reproducibility are proposed. These should be applied to differentiate between response categories for a future set of FDG-PET–based criteria that assess clinically significant changes in tumor response.

Purpose: Currently, guidelines for PET with 18F-fluorodeoxyglucose (FDG-PET) interpretation for assessment of therapy response in oncology primarily involve visual evaluation of FDG-PET/CT scans. However, quantitative measurements of the metabolic activity in tumors may be even more useful in evaluating response to treatment. Guidelines based on such measurements, including the European Organization for Research and Treatment of Cancer Criteria and PET Response Criteria in Solid Tumors, have been proposed. However, more rigorous analysis of response criteria based on FDG-PET measurements is needed to adopt regular use in practice. Experimental Design: Well-defined boundaries of repeatability and reproducibility of quantitative measurements to discriminate noise from true signal changes are a needed initial step. An extension of the meta-analysis from de Langen and colleagues (2012) of the test–retest repeatability of quantitative FDG-PET measurements, including mean, maximum, and peak standardized uptake values (SUVmax, SUVmean, and SUVpeak, respectively), was performed. Data from 11 studies in the literature were used to estimate the relationship between the variance in test–retest measurements with uptake level and various study-level, patient-level, and lesion-level characteristics. Results: Test–retest repeatability of percentage fluctuations for all three types of SUV measurement (max, mean, and peak) improved with higher FDG uptake levels. Repeatability in all three SUV measurements varied for different lesion locations. Worse repeatability in SUVmean was also associated with higher tumor volumes. Conclusions: On the basis of these results, recommendations regarding SUV measurements for assessing minimal detectable changes based on repeatability and reproducibility are proposed. These should be applied to differentiate between response categories for a future set of FDG-PET–based criteria that assess clinically significant changes in tumor response.

For many years, rhinologists and radiologists have had to rely upon conventional radiographs for the evaluation of paranasal sinus disease. The information gleaned from such studies is mainly relevant to the general condition of the larger paranasal sinuses, especially the frontal, maxillary, and sphenoid sinuses, and yields minimal information about the delicate bony anatomical or mucosal changes that may be present in the ethmoid air cells of the lateral wall of the nose. With the development of functional endoscopic sinus surgery (FESS), such imaging has proved inadequate. Today, computed tomography (CT) scanning and magnetic resonance imaging (MRI) are the standard means by which to image the paranasal sinuses and nasal cavity. CT is the preferred method of imaging when investigating benign inflammatory disease of the paranasal sinuses. This chapter provides a basic overview of CT scanning and its application to the imaging of the sinuses.

Historically, surgical procedures to alleviate recurrent or chronic sinusitis were directed at the larger paranasal sinuses. It was thought that the ventilation of these sinuses could be improved by creating new, and theoretically more effective, alternative drainage pathways. Alternative drainage procedures, such as the inferior meatal antrostomy, are now known not to redirect the flow of mucus through the newly created opening (the antrostomy), but only to act as a ‘drain’ when the mucociliary system is overwhelmed by mucus and pus. The persistence of symptoms following these procedures is usually secondary to persistent disease in the anterior ethmoid air cells affecting the natural ostia and the ostiomeatal complex. Recurrent sinus infections may also occur despite there being a widely patent natural accessory ostium when ostiomeatal complex disease is present.