Tomografía por emisión de positrones de cuerpo completo (PET/TAC) con 18F-fluorodesoxiglucosa

Imaging of Multiple Myeloma: Present and Future

Multiple myeloma (MM) is the second most common adult hematologic malignancy, and early intervention increases survival in asymptomatic high-risk patients. Imaging is crucial for the diagnosis and follow-up of MM, as the detection of bone and bone marrow lesions often dictates the decision to start treatment. Low-dose whole-body computed tomography (CT) is the modality of choice for the initial assessment, and dual-energy CT is a developing technique with the potential for detecting non-lytic marrow infiltration and evaluating the response to treatment. Magnetic resonance imaging (MRI) is more sensitive and specific than 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for the detection of small focal lesions and diffuse marrow infiltration. However, FDG-PET/CT is recommended as the modality of choice for follow-up. Recently, diffusion-weighted MRI has become a new technique for the quantitative assessment of disease burden and therapy response. Although not widespread, we address current proposals for structured reporting to promote standardization and diminish variations. This review provides an up-to-date overview of MM imaging, indications, advantages, limitations, and recommended reporting of each technique. We also cover the main differential diagnosis and pitfalls and discuss the ongoing controversies and future directions, such as PET-MRI and artificial intelligence.

[18F]FDG PET/CT in Short-Term Complications of COVID-19: Metabolic Markers of Persistent Inflammation and Impaired Respiratory Function

SARS-CoV-2 virus infects organs other than the lung, such as mediastinal lymph nodes, spleen, and liver, but, to date, metabolic imaging studies obtained in short-term follow-ups of patients hospitalized with severe COVID-19 infection are rare. Our objective was to evaluate the usefulness of [¹⁸F]FDG-PET/CT in the short-term follow-up of patients admitted for COVID-19 pneumonia and to explore the association of the findings with clinical prognostic markers. The prospective study included 20 patients with COVID-19 pneumonia (November 2020–March 2021). Clinical and laboratory test findings were gathered at admission, 48–72 h post-admission, and 2–3 months post-discharge, when [¹⁸F]FDG-PET/CT and respiratory function tests were performed. Lung volumes, spirometry, lung diffusion capacity for carbon monoxide (DLCO), and respiratory muscle strength were measured. Volumetric [¹⁸F]FDG-PET/CT results were correlated with laboratory and respiratory parameters. Eleven [¹⁸F]FDG-PET/CT (55%) were positive, with hypermetabolic mediastinal lymphadenopathy in 90.9%. Mediastinal lesion’s SUVpeak was correlated with white cells’ count. Eleven (55%) patients had impaired respiratory function, including reduced DLCO (35%). SUVpeak was correlated with %predicted-DLCO. TLG was negatively correlated with %predicted-DLCO and TLC. In the short-term follow-up of patients hospitalized for COVID-19 pneumonia, [¹⁸F]FDG-PET/CT findings revealed significant detectable inflammation in lungs and mediastinal lymph nodes that correlated with pulmonary function impairment in more than half of the patients.

[18F]-FDG PET/CT in oncologic patients with unsuspected asymptomatic infection with SARS-CoV-2

Purpose

Spain has been one of the most affected countries by the COVID-19 pandemic, being among the countries with worse numbers, including the death rate. However, most patients are asymptomatic, although they are very contagious. The objective of this study was to investigate the incidence in oncological patients infected with SARS-CoV-2 that are asymptomatic for COVID-19 and at home and that undergo PET/CT for oncologic indications, nonrelated to COVID-19, finding in the PET/CT lung alterations that are suggestive of SARS-CoV-2 infection.

Methods

During the period of maximum incidence of the global pandemic in one of the most affected regions of Spain, there were 145 patients that met inclusion and exclusion criteria and were included in the study. Imaging findings previously described such as ground-glass opacities with low [¹⁸F]-FDG uptake were considered images suspicious for SARS-CoV-2 infection. Patients with these findings were referred to RT-PCR testing and close follow-up to confirm the presence or absence of COVID-19.

Results

Suspicious lung imaging findings were present in 7 of 145 patients (4.8%). Five of these 7 patients were confirmed as presenting SARS-CoV-2 infection, this is, COVID-19. In the remaining two, it was not possible to confirm the presence of COVID-19 with RT-PCR, although in one of them, PET/CT allowed an early diagnosis of a lung infection related to a bacterial pneumonic infection that was promptly and adequately treated with antibiotics.

Conclusion

These results confirm that the prevalence of SARS-CoV-2 infection is higher than suspected and that there are asymptomatic patients that are attending imaging departments to be explored for their baseline oncologic processes. In these patients, PET/CT allows an early diagnosis of COVID-19.

Development of a positron emission tomography risks map

Patient safety is an essential component of quality of care, especially when the complexity of care has reached extreme levels. Currently achieving this safety is considered a basic strategy of the National Health System. Nuclear Medicine departments have certain peculiarities that make them special in terms of patient safety, with situations that go beyond the common healthcare practice of other departments. Namely, that both encapsulated and non-encapsulated ionizing radiation is used in daily practice, and numerous groups of professionals must be coordinated to undertake positron emission tomography (PET) specifically, from the clinical management unit itself, and from other departments of the hospital (as well as companies outside the hospital itself and the Public Health System). The objective of this paper was to identify the risks to which a patient who is to be explored through PET can be exposed in a Nuclear Medicine department and draw up a risk map for the PET process. The methodology used is part of the proposal of the Ministry of Health (2007), and its practical implementation (given the limited literature available on Nuclear Medicine), follows as far as possible that of related care areas (radiodiagnosis and radiotherapy). For this purpose, a multidisciplinary team of professionals directly related to the PET process was created, using the modal analysis of faults and effects methodology to identify possible failures, their causes and the potential adverse events causing each. As a final step, a risk map was created, locating the previously identified faults at each stage of the process. This paper exposes the PET process, and describes the risks that patients might run when a PET scan is required, as well as the adverse events deriving from it. All this is shown in a risk map of the PET process.

Febrile syndrome of unknown origin: Indications for 18F-FDG PET/CT in inflammatory and infectious processes

Fever of unknown origin is defined as a body temperature greater than 38.3°C lasting more than three weeks for which the cause could not be found within one week of hospital admission. More than 200 causes have been reported, and these can be classified into four categories: infections, inflammatory diseases, oncologic processes, and miscellaneous conditions. Noninvasive diagnostic techniques are used in 69.2% of cases and invasive techniques in 30.8%. Structural imaging techniques show the morphological changes from infectious, inflammatory, and tumor-related processes, but they do not allow the detection of the early changes brought about by these processes. The metabolic information provided by ¹⁸F-FDG PET/CT has a promising role in these patients. ¹⁸F-FDG uptake is based on the cells' use of glucose as a source of energy, so it can be observed in infectious, inflammatory, and tumor-related processes. The established non-oncologic indications for ¹⁸F-FDG PET/CT are sarcoidosis, osteomyelitis, spondylodiscitis, fever of unknown origin, and vasculitis, which together account for more than 85% of studies.

Heterogeneity in [18F]fluorodeoxyglucose positron emission tomography/computed tomography of non-small cell lung carcinoma and its relationship to metabolic parameters and pathologic staging

To investigate the relationships between tumor heterogeneity, assessed by texture analysis of [18F]fluorodeoxyglucose-positron emission tomography (FDG-PET) images, metabolic parameters, and pathologic staging in patients with non-small cell lung carcinoma (NSCLC). A retrospective analysis of 38 patients with histologically confirmed NSCLC who underwent staging FDG-PET/computed tomography was performed. Tumor images were segmented using a standardized uptake value (SUV) cutoff of 2.5. Five textural features, related to the heterogeneity of gray-level distribution, were computed (energy, entropy, contrast, homogeneity, and correlation). Additionally, metabolic parameters such as SUVmax, SUVmean, metabolic tumor volume (MTV), and total lesion glycolysis (TLG), as well as pathologic staging, histologic subtype, and tumor diameter, were obtained. Finally, a correlation analysis was carried out. Of 38 tumors, 63.2% were epidermoid and 36.8% were adenocarcinomas. The mean ± standard deviation values of MTV and TLG were 30.47 ± 25.17 mL and 197.81 ± 251.11 g, respectively. There was a positive relationship of all metabolic parameters (SUVmax, SUVmean, MTV, and TLG) with entropy, correlation, and homogeneity and a negative relationship with energy and contrast. The T component of the pathologic TNM staging (pT) was similarly correlated with these textural parameters. Textural features associated with tumor heterogeneity were shown to be related to global metabolic parameters and pathologic staging.

Ability of FDG-PET/CT in the detection of gallbladder cancer

PURPOSE

To assess the value of FDG-PET/CT in the evaluation of gallbladder carcinomas (GBC).

METHODS

A prospective cohort of patients with suspicion of or confirmed GBC was studied with FDG-PET/CT. Diagnostic accuracy parameters were calculated in comparison with pathology and/or the clinical course of patients. Clinical impact of PET/CT imaging was estimated.

RESULTS

Forty-nine patients were enrolled (34 malignant tumors, 15 benign lesions; 37 staging, 12 restaging). Overall diagnostic accuracy was 95.9% for the diagnosis of the primary lesion, 85.7% for lymph node involvement and 95.9% for metastatic disease. Mean SUVmax in malignant gallbladder lesions was 7.92 ± 6.25 Analysis of ROC curves showed a SUVmax cut-off value of 3.62 for malignancy (S: 78.1%; Sp: 88.2%). Diagnostic accuracy in the restaging group reached 100%. FDG-PET/CT changed the management of 22.4% of the population.

COMMENTS

Diagnosis of malignancy or benignity of suspicious gallbladder lesions is accurately made with FDG PET/CT, allowing a precise staging of GBC due to its ability to identify unsuspected metastatic disease. SUVmax has a complementary role in addition to visual analysis.

Dual time point 2-deoxy-2-[18F]fluoro-D-glucose PET/CT: nodal staging in locally advanced breast cancer

AIM

To assess dual time point 2-deoxy-2-[(18)F]fluoro-D-glucose (18)(F)FDG PET-CT accuracy in nodal staging and in detection of extra-axillary involvement.

MATERIAL AND METHODS

Dual time point [(18)F] FDG PET/CT scan was performed in 75 patients. Visual and semiquantitative assessment of lymph nodes was performed. Semiquantitative measurement of SUV and ROC-analysis were carried out to calculate SUV(max) cut-off value with the best diagnostic performance. Axillary and extra-axillary lymph node chains were evaluated.

RESULTS

Sensitivity and specificity of visual assessment was 87.3% and 75%, respectively. SUV(max) values with the best sensitivity were 0.90 and 0.95 for early and delayed PET, respectively. SUV(max) values with the best specificity were 1.95 and 2.75, respectively. Extra-axillary lymph node involvement was detected in 26.7%.

CONCLUSION

FDG PET/CT detected extra-axillary lymph node involvement in one-fourth of the patients. Semiquantitative lymph node analysis did not show any advantage over the visual evaluation.

Surgical adhesive may cause false positives in integrated positron emission tomography and computed tomography after lung cancer resection

Surgical adhesives are frequently used after pulmonary resection to prevent or reduce pulmonary air leakages, since leakages may cause complications delaying the removal of chest drainage tubes and prolonging in-hospital stay. In this paper, we present 2 patients who underwent curative-intent pulmonary resection for non-small-cell lung carcinoma, in which the biological adhesive BioGlue(®) was used. Follow-up fluoro-2-deoxy-D-glucose positron emission tomography/computed tomographic (FDG-PET/CT) imaging revealed hypermetabolic pulmonary nodular lesions. Subsequent surgical exploration showed that the lesions were foreign body reactions to the bioadhesive. To our knowledge, this is the first study to examine false-positive follow-up FDG-PET/CT scans caused by the use of BioGlue(®) in pulmonary resection procedures.

Recommendations of the Spanish Societies of Radiation Oncology (SEOR), Nuclear Medicine & Molecular Imaging (SEMNiM), and Medical Physics (SEFM) on (18)F-FDG PET-CT for radiotherapy treatment planning

Positron emission tomography (PET) with (18)F-fluorodeoxyglucose (FDG) is a valuable tool for diagnosing and staging malignant lesions. The fusion of PET and computed tomography (CT) yields images that contain both metabolic and morphological information, which, taken together, have improved the diagnostic precision of PET in oncology. The main imaging modality for planning radiotherapy treatment is CT. However, PET-CT is an emerging modality for use in planning treatments because it allows for more accurate treatment volume definition. The use of PET-CT for treatment planning is highly complex, and protocols and standards for its use are still being developed. It seems probable that PET-CT will eventually replace current CT-based planning methods, but this will require a full understanding of the relevant technical aspects of PET-CT planning. The aim of the present document is to review these technical aspects and to provide recommendations for clinical use of this imaging modality in the radiotherapy planning process.

Richter's syndrome: Utility of ¹⁸F-FDG PET/CT

Richter's syndrome (RS) refers to transformation of the chronic lymphoid leukemia (CLL) to a diffuse large cell lymphoma. Prognosis of patients with RS is generally considered unfavorable. We present two cases of patients with history of CLL, who had an increased of the lymphadenopathy, with elevated lactate dehydrogenase (LDH) in serum and increased (18)F-FDG uptake of the neck lymph nodes, with subsequent confirmation of RS by histology.

Normal blood glucose level and (18)F-FDG PET/CT

Patient preparation for FDG PET studies is perhaps more critical and more complex than for any other commonly performed imaging procedure. We report a patient with normal blood glucose level prior to the execution of a PET study in which FDG uptake was virtually zero in internal organs and was very extense in large muscle groups. The patient recognizes ingestion several minutes before the test. Ten days later, a repeated PET scan with normal blood glucose level, showed a normal organs distribution of FDG.

18F-FDG retention index and biologic prognostic parameters in breast cancer

AIM

To analyze the correlation between [(18)F]-fluoro-2-deoxy-D-glucose (F-FDG) uptake assessed by positron emission tomography/computed tomography (PET/CT) in breast tumors and histopathologic and immunohistochemical prognostic factors.

MATERIAL AND METHODS

Sixty-eight women with breast cancer were prospectively evaluated. PET/CT was requested in the initial staging previous to neoadjuvant chemotherapy (multicentric study).All the patients underwent a standard (18)F-FDG PET/CT followed by a delayed acquisition, 1 hour (PET-1) and 3 hours (PET-2) after FDG administration. Both examinations were evaluated qualitatively and semiquantitatively (SUV(max) values) in PET-1 (SUV-1) and in PET-2 (SUV-2). The percentage variation of the standard uptake values (retention index) between PET-1 and PET-2 was calculated.Clinical and metabolic stages were assessed according to TNM classification. All biologic prognostic parameters, such as the receptor status, p53 and c-erbB-2 expression, proliferation rate (Ki-67), and grading were determined from tissue of the primary tumor. Metabolic, clinical, and biologic parameters were correlated.

RESULTS

A positive relationship was found between the SUV(max), tumor size, clinical, and metabolic stages. SUV-1 and SUV-2 values showed significant statistical correlation (P < 0.05) with PET stage and tumor size assessed by PET. On the contrary, the retention index showed relation with clinical stage (P < 0.05).When related to the biologic parameters, retention index showed the best results, with positive and significant relation (P < 0.05), with histologic grade, and Ki-67 and c-erbB-2 expression. Isolated SUV values only showed significant relation to Ki-67 expression.

CONCLUSION

The retention index showed the best relation with biologic and clinical parameters compared with isolated SUVmax values for what could be a predictive marker of tumor biologic behavior.

[Analysis of cost-effectiveness in the diagnosis of fever of unknown origin and the role of (18)F-FDG PET-CT: a proposal of diagnostic algorithm]

AIM

To analyze the costs of Fever of Unknown Origin (FUO) prior to the PET-CT study. To determine the effectiveness of PET-CT in the diagnosis of FUO. A proposal of diagnostic algorithm.

MATERIAL AND METHODS

A retrospective study was performed that included 20 patients who had been studied between January 2007 and January 2011, with a mean age of 57.75 years and FUO diagnosis. All underwent a PET-CT study with (18)F-FDG. Individual and mean costs of FUO in these patients were assessed, including hospitalization days and complementary tests prior to the PET-CT study. The effectiveness of the PET-CT study in the diagnosis of FUO was analyzed. Costs of the FUO process were determined, including those of the PET-CT study, and if it had been done earlier in the diagnostic process.

RESULTS

Mean hospital stay per patient until the PET-CT study was 28 days. The cost per hospitalization day was 342 €. Average cost per patient in complementary tests was 1395 €. Total cost of the FUO process until the PET-CT study was around 11167 € per patient. The PET-CT study showed a 78% sensitivity, 83% specificity, 92% PPV and 62% NPV. If PET-CT had been performed earlier in the FUO process, assuming the same effectiveness, 5471 € per patient would have been saved.

CONCLUSION

The PET-CT study could be cost-effective in the FUO process if used at an early stage, helping to establish an early diagnosis, reducing hospitalization days due to diagnostic purposes and the repetition of unnecessary tests.

18F-FDG-PET/CT in the surveillance of patients with lymphoma: detection of asymptomatic recurrences

AIM

To assess the diagnostic accuracy of (18)F-FDG-PET/CT in detecting asymptomatic recurrences in patients with lymphoma. To define uptake patterns of recurrence indicative of recurrence.

MATERIAL AND METHODS

Those patients with lymphoma who fulfilled the following inclusion criteria of clinical complete remission and negative PET/CT study were included retrospectively and longitudinally. Conventional surveillance of these patients was performed only by (18)F-FDG PET/CT following a standardized procedure. Pathologic locations (supra- and infradiaphragmatic) and their character (single or multiple) were analyzed in order to determine reliable metabolic patterns of recurrence. The final diagnosis was established by histopathological analysis or clinical follow-up greater than 8 months.

RESULTS

A total of 199 explorations belonging to 106 patients with lymphoma were included. Of these patients, 59 had Hodgkin's lymphoma and 47 non-Hodgkin's lymphoma. There was suspicion of relapse from the metabolic point of view in 27 of the PET/CT scans. Of these, 14 (10 patients) were false positive (FP), and 13 (8 patients) true positive. The remaining studies were true negative, no false negatives being detected. The pattern most frequently related to recurrence was infradiaphragmatic lymph node involvement while most of the FP had isolated supradiaphragmatic involvement. Sensitivity, specificity, PPV, NPV and diagnostic accuracy of PET/CT parameters for the study were 100%, 92%, 48%, 100% and 93%, respectively.

CONCLUSION

(18)F-FDG-PET/CT is a sensitive technique in the detection of asymptomatic recurrences in patients with lymphoma during their follow-up. Multiple character and infradiaphragmatic locations were the patterns that best correlated to the diagnosis of recurrence.

Is a selective brain (18)F-FDG PET/CT study profitable in patients with small cell lung cancer?

AIM

To evaluate the diagnostic yield of a selective brain (18)F-FDG PET/CT in neurologically asymptomatic patients with small cell lung cancer.

MATERIAL AND METHODS

Twenty-one neurologically asymptomatic patients referred to our service between July 2008 and December 2009 for staging of small cell lung cancer were included in the study. All underwent a standard (18)F-FDG PET/CT study followed by a selective brain PET/CT. The neurological findings were confirmed by CT scan with intravenous contrast, MRI or minimum clinical follow-up of 6 months. The brain PET/CT was considered positive if any alteration was observed in the FDG distribution that was not related with previously known benign lesion in the CT image.

RESULTS

Brain metastases were detected in 5 of the 21 patients (23.8%), these being correctly classified in 3 of them by the selective brain PET/CT. The stage was upgraded in one of them with the selective brain study. Only one patient showed a hypermetabolic lesion in the PET images in relationship to the lesions observed in the CT images. Sensibility, specificity, positive predictive value and negative predictive value were 60, 100, 100 and 88.89%, respectively.

CONCLUSION

Hypometabolic areas in the cerebral parenchyma are frequently associated to metastatic lesions in patients with small cell lung cancer. The selective brain PET/CT in these patients allows correct staging and early treatment of unsuspected metastasis.

Clinical relevance of incidental finding of focal uptakes in the colon during 18F-FDG PET/CT studies in oncology patients without known colorectal carcinoma and evaluation of the impact on management

AIMS

To assess the significance and the impact of focal FDG uptake in the colon in oncology patients without known colorectal carcinoma.

MATERIALS AND METHODS

A retrospective study was undertaken on 2,220 (18)F-FDG PET/CT studies carried out consecutively in the Nuclear Medicine Department in our hospital from 2 December 2008 to 31 May 2010. Inclusion criteria were patients with abnormal (18)F-FDG uptake in colorectal area that could not be explained (or not previously known) by their clinical histories. Patients previously diagnosed with colorectal carcinoma were excluded. A total of 86 patients (57 male, average age 63.4, range 46-85) were finally included. Colonoscopy with biopsy was established as a reference test. The impact of these findings on the diagnostic-therapeutic management in these patients was evaluated.

RESULTS

A colonoscopy was performed in 54 of the 86 patients, this examination not having been done up-to-date in the remaining 32 patients. Biopsy was obtained in 43 lesions of the 54 patient in whom a colonoscopy was performed. Colon disease was detected in 49 of these 54 patients, obtaining 54 FDG incidental foci which corresponded to 10 previously unsuspected primary colorectal carcinoma, 3 metastases, 27 adenomatous polyps with different degrees of dysplasia and 14 inflammatory processes. In the remaining 5 patients, the colonoscopy was normal. PET/CT modified the diagnostic and treatment management in most of the patients (49/54, that is 91%).

CONCLUSIONS

These results confirm the need to determine the cause of abnormal (18)F-FDG colorectal uptakes in the PET/CT studies by using colonoscopy and biopsy. This approach allows for the detection and early treatment of malignant and premalignant lesions.

[Positron tomography with 18F-fluorodeoxyglucose in the preoperative evaluation of gall bladder lesions suspicious of malignancy. Diagnostic utility and clinical impact]

BACKGROUND

Gallbladder carcinoma is a neoplasm having a poor prognosis in which the role of the positron emission tomography with (18)F-fluordeoxyglucose as a diagnostic tool, although of possible usefulness, has not been well-defined.

METHODS/DESIGN

It is a prospective cohort of patients with radiologically malignant suspicious gallbladder lesions. A staging diagnostic presurgical FDG-PET study was carried out in each patient using both dedicated PET and multimodality PET-CT scanners. Diagnostic accuracy parameters were calculated from the results of PET imaging and were correlated with the condition and/or the clinical course of the patients. The clinical impact of its implementation in the diagnosis of gallbladder carcinoma was also analyzed.

RESULTS

A total of 42 patients were recruited (22 malignant lesions, 20 benign). Overall diagnostic accuracy was 83.33% for the diagnosis of the primary lesion, 88.89% for the evaluation of lymph node involvement and 85.1% for the evaluation of metastatic disease. Mean SUVmax in malignant gallbladder lesions was 6.14±2.89. ROC curve showed a cut-off value of 3.65 in the SUVmax for malignancy. Accuracy of PET studies alone (n=21) was slightly lower than that of the PET/CT (n=21). FDG-PET changed the management of 14.8% of the population due to the identification of unsuspected metastatic disease.

COMMENTS

FDG-PET accurately diagnoses malignancy or benignity of suspicious gallbladder lesions, with the addition of its capacity to identify unsuspected metastatic disease. PET-CT improves the diagnostic accuracy of the procedure, due to the metabolic-structural complementarity of their information. The SUVmax has a complementary value added to the visual analysis.

[Utility of PET/CT for mediastinal staging of non-small cell lung cancer in stage III (N2)]

PURPOSE

To evaluate the accuracy of integrated positron emission tomography with (18)F-fluoro-2-deoxy-D-glucose (FDG) and computed tomography (PET/CT) in mediastinal lymph node staging in patients with potentially operable (N2) non-small cell lung cancer (NSCLC) and to ascertain the role of invasive staging in verifying positron emission tomography (PET)/computed tomography (CT) results.

MATERIAL AND METHODS

A retrospective study of consecutive patients with pathologically-proven NSCLC and N2 staging by enhanced CT was performed. A PET/CT scan was performed for all the patients. Lymph node staging was pathologically confirmed when it was possible or by consensus in the Thoracic Cancer Committee. Sensitivity, specificity, negative predictive value and positive predictive value of PET/CT in N2 cases were determined.

RESULTS

A total of 34 patients with N2 by CT were evaluated. PET/CT showed N2 in 30 patients. Discrepancies were found in four patients, two patients were classified as N1 in PET/CT and two patients as N0. Lymph node staging was pathologically confirmed in 20 patients. No false positives were found in PET/CT study. Sensitivity was 94.7%, specificity and positive predictive values were 100% and negative predictive value was 50%.

CONCLUSIONS

Our data show that integrated PET/CT provides high sensitivity and positive predictive value in mediastinal nodal staging of NSCLC patients. Therefore, in patients with potentially resectable lung cancer, neoadjuvant chemotherapy candidate, mediastinoscopy could be reserved for restaging after induction therapy.

[18F-FDG PET/CT with retrograde filling of the urinary bladder in the assessment of malignant pelvic disease]

AIM

To assess the role of PET/CT with retrograde filling of urinary bladder (RFUB) in the assessment of pelvic malignancy in patients with urothelial or gynecological tumors.

MATERIAL AND METHODS

A retrospective longitudinal analysis based on 62 studies belonging to 52 patients was performed. All of them had a history of pelvic malignancy (29 urothelial and 23 gynecological) and 42 had undergone previous treatments. All patients underwent a standard PET/CT protocol. Inclusion criteria were radiological alterations in pelvic organs or increased urinary activity of (18)F-FDG that hindered evaluation of the pelvic structures. Pathological pelvic locations were assessed as the additional value of PET/CT with RFUB. The pathologic lesions were histologically or clinically evaluated with a minimum follow-up of 12 months.

RESULTS

Pelvic malignancy was confirmed in 33 cases, 16 of which were of urothelial origin. A total of 35/62 studies showed a pathologic PET/CT in pelvis, 4 of them were false positive and 2 false negative. In 19 cases, malignancy was detected in the bladder wall, 16 of which were true positive. No false negative was detected. Regarding standard imaging acquisition, RFUB helped to confirm or rule out bladder and/or gynecological disease in 54 cases.

CONCLUSION

Retrograde bladder filling is a highly recommended technique in the assessment of malignant pelvic disease, especially of bladder origin.

Is FDG-PET suitable for evaluating neoadjuvant therapy in non-small cell lung cancer? Evidence with systematic review of the literature

BACKGROUND

Neoadjuvant therapy response assessment is crucial in patients with non-small cell lung cancer (NSCLC). FDG-PET has emerged as a valuable tool for defining therapy response assessment in other tumours.

AIM

To systematically review publications appearing in the literature describing induction therapy response assessment with FDG-PET in NSCLC.

METHODS

We performed a bibliographic search and selected only prospective studies in order to include the highest levels of evidence.

RESULTS

Nine of 497 potentially relevant publications were selected. The ranges of sensitivity, specificity, positive predictive value and negative predictive value for primary tumour response assessment were 80-100%, 0-100%, 42.9-100%, and 66.7-100%, respectively. Pooling data for N2 restaging after neoadjuvant response the overall sensitivity was 63.8% (95% CI, 53.3-73.7%) and overall specificity was 85.3% (95% CI, 80.4-89.4%).

CONCLUSION

The results of the analysis do not support the use of FDG-PET as the only re-assessment tool for mediastinal lymph node evaluation for routine clinical use. FDG-PET seems to predict primary tumour response to induction therapy but it could not be shown by pooling analysis.