Preoperative Thoracic CT Findings Associated With Postoperative Mechanical Ventilation in Patients Undergoing Major Abdominal or Pelvic Surgery: A Matched Case-Control Study.

BACKGROUND. Postoperative prolonged mechanical ventilation is associated with increased morbidity and mortality. Reliable predictors of the need for postoperative mechanical ventilation after abdominal or pelvic surgeries are lacking. OBJECTIVE. The purpose of this study was to explore associations between preoperative thoracic CT findings and the need for postoperative mechanical ventilation after major abdominal or pelvic surgeries. METHODS. This retrospective case-control study included patients who underwent abdominal or pelvic surgeries during the period from January 1, 2014, through December 31, 2018, and had undergone preoperative thoracic CT. Case patients were patients who required postoperative mechanical ventilation. Control patients and case patients were matched at a 3:1 ratio on the basis of age, sex, body mass index, chronic obstructive pulmonary disease, smoking status, and surgery type. Two radiologists (readers 1 and 2) reviewed the CT images. Findings were compared between groups. RESULTS. The study included 165 patients (70 women, 95 men; mean age, 67.0 ± 9.7 [SD] years; 42 case patients and 123 matched control patients). Bronchial wall thickening and pericardial effusion were more frequent in case patients than control patients for reader 2 (10% vs 2%, p = .03; 17% vs 5%, p = .01) but not for reader 1. Pulmonary artery diameter (mean ± SD) was greater in case patients than control patients for reader 2 (2.9 ± 0.5 cm vs 2.8 ± 0.5 cm, p = .045) but not reader 1. Right lung height was lower in case patients than control patients for reader 1 (18.4 ± 2.9 cm vs 19.9 ± 2.7 cm, p = .01) and reader 2 (18.3 ± 2.9 cm vs 19.8 ± 2.7 cm, p = .01). Left lung height was lower in case patients than control patients for reader 1 (19.5 ± 3.1 cm vs 21.1 ± 2.6 cm, p = .01) and reader 2 (19.6 ± 2.4 cm vs 20.9 ± 2.6 cm, p = .01). Anteroposterior (AP) chest diameter was greater for case patients than control patients for reader 1 (14.0 ± 2.3 cm vs 12.9 ± 3.7 cm, p = .02) and reader 2 (14.2 ± 2.2 cm vs 13.2 ± 3.6 cm, p = .04). In a multivariable regression model using pooled reader data, bronchial wall thickening exhibited an odds ratio (OR) of 4.6 (95% CI, 1.3-16.5; p = .02); pericardial effusion, an OR of 5.1 (95% CI, 1.7-15.5; p = .004); pulmonary artery diameter, an OR of 1.4 per 1-cm increase (95% CI, 0.7-3.0; p = .32); mean lung height, an OR of 0.8 per 1-cm increase (95% CI, 0.7-1.001; p = .05); and AP chest diameter, an OR of 1.2 per 1-cm increase (95% CI, 1.013-1.4; p = .03). CONCLUSION. CT features are associated with the need for postoperative mechanical ventilation after abdominal or pelvic surgery. CLINICAL IMPACT. Many patients undergo thoracic CT before abdominal or pelvic surgery; the CT findings may complement preoperative clinical risk factors.

Radiological approach to cavitary lung lesions.

Cavitary lesions in the lung are not an uncommon imaging encounter and carry a broad differential diagnosis that includes a wide range of pathological conditions from cancers, infections/inflammatory processes to traumatic and congenital lung abnormalities. In this review article, we describe a comprehensive approach for evaluation of cavitary lung lesions and discuss the differential diagnosis in the light of radiological findings.

Lung Cancer Recurrence: 18F-FDG PET/CT in Clinical Practice.

OBJECTIVE: The purpose of this article is to summarize the clinical utility of 18F-FDG PET/CT in the evaluation of lung cancer recurrence with an emphasis on typical anatomic and metabolic patterns of recurrence, expected posttherapeutic changes, and common pitfalls of FDG PET/CT. FDG PET/CT is useful in assessing therapeutic response and in determining the extent of recurrent disease and provides a guide for targeted biopsy. CONCLUSION: FDG PET/CT plays a crucial role in the evaluation of therapeutic response in lung cancer and guides management.

Atherosclerosis on CT Angiogram Predicts Acute Kidney Injury After Transcatheter Aortic Valve Replacement.

OBJECTIVE: The purpose of this study is to determine the association of vascular calcification and renal artery stenosis on CT angiogram (CTA) obtained before transcatheter aortic valve replacement (TAVR) with postprocedure acute kidney injury (AKI). MATERIALS AND METHODS: In this single-center retrospective cohort study, 106 pre-TAVR CTAs were evaluated by two independent blinded readers. Renal artery stenosis was visually graded as less than 50% or greater than or equal to 50% luminal narrowing. Calcification of the aorta and iliac arteries was scored from 0 (no calcification) to 3 (severe calcification) and was summed to develop a calcification score. Univariate comparisons between patients who did and did not develop AKI were made for radiologic measurements. Multivariable logistic regression was used to assess association of renal artery stenosis and atherosclerotic calcification with post-TAVR AKI. RESULTS: Post-TAVR AKI occurred in 20 of 106 patients. Subjects with bilateral main renal artery stenosis greater than or equal to 50% had significantly greater odds (odds ratio, 4.84; 95% CI, 1.41-16.54; p = 0.01) of developing post-TAVR AKI than did subjects with unilateral or no stenosis greater than or equal to 50% in the main renal arteries. Subjects who developed post-TAVR AKI had significantly higher aortic and iliac arterial calcification scores compared with subjects who did not develop post-TAVR AKI (mean ± SD, 21.4 ± 5.6 vs 17.9 ± 6.7; p = 0.04). CONCLUSION: AKI as a complication of TAVR is more likely to develop in patients with bilateral renal artery stenosis greater than or equal to 50% or severe atherosclerotic calcification of the aorta and iliac arteries.

Neuroendocrine Tumor Diagnosis and Management: 68Ga-DOTATATE PET/CT.

OBJECTIVE: The purpose of this article is to provide a review of the use of 68Ga tetraazacyclododecanetetraacetic acid-DPhe1-Tyr3-octreotate (DOTATATE) PET/CT, a functional imaging modality for assessment of well-differentiated neuroendocrine tumors (NETs). It has become the preferred imaging modality for initial diagnosis, selection of patients for peptide receptor radionuclide therapy, and localization of unknown primary tumors. The National Comprehensive Cancer Network guideline has added 68Ga-DOTATATE PET/CT as an appropriate test in the management of NETs. CONCLUSION: In combination with FDG PET/CT, 68Ga-DOTATATE PET/CT can noninvasively assess tumor heterogeneity, especially in G2 and G3 NETs, for personalized management of patients.

Role of FDG PET/CT in the Eighth Edition of TNM Staging of Non-Small Cell Lung Cancer.

Lung cancer is the leading cause of cancer-related mortality in the United States, and accurate staging plays a vital role in determining prognosis and treatment. The recently revised eighth edition of the TNM staging system for lung cancer defines new T and M descriptors and updates stage groupings on the basis of substantial differences in survival. There are new T descriptors that are based on the findings at histopathologic examination, and T descriptors are reassigned on the basis of tumor size and extent. No changes were made to the N descriptors in the eighth edition of the TNM staging of lung cancer, because the four N categories that are based on the location of the diseased nodes can be used to consistently predict prognosis. The eighth edition includes a new M1b descriptor for patients with a single extrathoracic metastatic lesion in a single organ (M1b), because they have better survival and different treatment options, compared with those with multiple extrathoracic lesions (M1c). Examination with fluorine 18 fluorodeoxyglucose (FDG) PET/CT is the standard of care and is an integral part of the clinical staging of patients with lung cancer. To provide the treating physicians with accurate staging information, radiologists and nuclear medicine physicians should be aware of the updated classification system and should be cognizant of the site-specific strengths and limitations of FDG PET/CT. In this article, the eighth edition of the TNM staging system is reviewed, as well as the role of FDG PET/CT in the staging of non-small cell lung carcinoma. ©RSNA, 2018.

Extraosseous Findings on Bone Scintigraphy Using Fusion SPECT/CT and Correlative Imaging.

OBJECTIVE: Extraosseous radioactivity outside of the expected biodistribution is often encountered on (99m)Tc-methylene diphosphate (MDP) bone scintigraphy, and proper interpretation requires an understanding of the mechanisms underlying this uptake and knowledge of the possible causes, depending on the site or structure involved. CONCLUSION: We present examples of extraosseous radiotracer uptake seen on (99m)Tc-MDP bone scans in which either SPECT with integrated CT or correlative imaging improved the study's interpretation.

Quarter-Century PET/Computed Tomography Transformation of Oncology: Hepatobiliary and Pancreatic Cancer.

[18F] Fluorodeoxyglucose (18F-FDG) PET/CT can improve the staging accuracy and clinical management of patients with hepatobiliary and pancreatic cancers, by detection of unsuspected metastases. 18F-FDG PET/CT metabolic parameters are valuable in predicting treatment response and survival. Metabolic response on 18F-FDG PET/CT can predict preoperative pathologic response to neoadjuvant therapy in patients with pancreatic cancer and determine prognosis. Several novel non-FDG tracers, such as 68Ga prostate-specific membrane antigen (PSMA) and 68Ga-fibroblast activation protein inhibitor (FAPI) PET/CT, show promise for imaging hepatobiliary and pancreatic cancers with potential for radioligand therapy.

Augmentation of Radioiodine Uptake by Pulmonary Metastasis of Papillary Thyroid Carcinoma Treated with Dabrafenib and Trametinib.

Redifferentiation therapy with Dabrafenib (a BRAF inhibitor) and Trametinib (a MEK inhibitor) restores radioiodine avidity of radioiodine-refractory papillary thyroid carcinoma (PTC). A 50-year-old man was diagnosed with radioiodine-refractory PTC pulmonary metastasis post prior total thyroidectomy and radioiodine ablation. The patient was treated with Dabrafenib and Trametinib, followed by second radioiodine ablation with I-131 sodium iodine. Diffuse increased radioiodine uptake by pulmonary metastasis was visualized on post ablation whole body scan. Response to second radioiodine ablation was demonstrated by decrease in size of pulmonary nodules seen on chest CT, along with decrease of thyroglobulin level.

Fibrin-Associated Large B-Cell Lymphoma (FA-LBCL) Involving Solid Organs as Necrotic Cystic Lesions-A Rare Entity with Potential Diagnostic Pitfalls: A Two-Case Series and Review of the Literature.

Fibrin-associated large B-cell lymphoma (FA-LBCL) is a rare subtype of Epstein-Barr virus (EBV)-associated lymphoma, recognized as an independent entity per the 5th edition of the WHO classification of hematolymphoid neoplasms. It is usually associated with longstanding chronic inflammation and arises within fibrinous material in confined anatomic spaces. We report the clinicopathologic manifestations of two patients of FA-LBCL involving the adrenal gland and kidney. Both tumors were diagnosed after presenting as cystic masses on imaging studies. These lymphomas were non-invasive, with microscopic aggregates of large B-lymphoma cells along/within cystic wall and admixed with fibrinous material and without prominent inflammation. By immunohistochemistry and in-situ hybridization, lymphoma cells were positive for CD45, PAX5, CD79a, MUM1, BCL2, PD-L1, and EBV/EBER (Epstein-Barr virus encoded small RNA) with a high proliferation index. Both patients remain in remission after management with complete surgical resection and additional chemo-immunotherapy in one patient. Considering its rarity, scant tumor cells, and varied clinical presentations, FA-LBCL may pose diagnostic challenges, especially when presenting as extensively necrotic cystic lesions, needing multidisciplinary collaboration in formulating management.

ACR Appropriateness Criteria® Pulmonary Arteriovenous Malformation (PAVM): 2023 Update.

Pulmonary arteriovenous malformations (PAVMs) occur in 30% to 50% of patients with hereditary hemorrhagic telangiectasia. Clinical presentations vary from asymptomatic disease to complications resulting from the right to left shunting of blood through the PAVM such as paradoxical stroke, brain abscesses, hypoxemia, and cardiac failure. Radiology plays an important role both in the diagnosis and treatment of PAVM. Based on different clinical scenarios, the appropriate imaging study has been reviewed and is presented in this document. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

ACR Appropriateness Criteria® Sepsis.

Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection. A search for the underlying cause of infection typically includes radiological imaging as part of this investigation. This document focuses on thoracic and abdominopelvic causes of sepsis. In 2017, the global incidence of sepsis was estimated to be 48.9 million cases, with 11 million sepsis-related deaths (accounting for nearly 20% of all global deaths); therefore, understanding which imaging modalities and types of studies are acceptable or not acceptable is imperative. The 5 variants provided include the most commonly encountered scenarios in the setting of sepsis along with recommendations and data for each imaging study. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Gastroenteropancreatic Neuroendocrine Tumor Diagnosis: DOTATATE PET/CT.

Gastroenteropancreatic neuroendocrine tumors(NETs), which arise from the small intestine, rectum, colon, appendix, or pancreas, have variable malignant potential with clinical behavior determined by proliferative activity according to the Ki-67 index and tumor differentiation. Somatostatin receptor (SSTR) expression by NETs allows SSTR imaging using 68Ga-DOTATATE PET/computed tomography (CT) and treatment with octreotide or SSTR-targeted peptide receptor radionuclide therapy (PRRT). 68Ga-DOTATATE PET/CT is indicated for localization of the primary tumor in select cases, staging patients with known NET, and selecting patients for PRRT. NCCN guidelines consider imaging with 68Ga-DOTATATE PET/CT appropriate for staging and receptor status assessment.

Tumor loss-of-function mutations in STK11/LKB1 induce cachexia.

Cancer cachexia (CC), a wasting syndrome of muscle and adipose tissue resulting in weight loss, is observed in 50% of patients with solid tumors. Management of CC is limited by the absence of biomarkers and knowledge of molecules that drive its phenotype. To identify such molecules, we injected 54 human non-small cell lung cancer (NSCLC) lines into immunodeficient mice, 17 of which produced an unambiguous phenotype of cachexia or non-cachexia. Whole-exome sequencing revealed that 8 of 10 cachexia lines, but none of the non-cachexia lines, possessed mutations in serine/threonine kinase 11 (STK11/LKB1), a regulator of nutrient sensor AMPK. Silencing of STK11/LKB1 in human NSCLC and murine colorectal carcinoma lines conferred a cachexia phenotype after cell transplantation into immunodeficient (human NSCLC) and immunocompetent (murine colorectal carcinoma) models. This host wasting was associated with an alteration in the immune cell repertoire of the tumor microenvironments that led to increases in local mRNA expression and serum levels of CC-associated cytokines. Mutational analysis of circulating tumor DNA from patients with NSCLC identified 89% concordance between STK11/LKB1 mutations and weight loss at cancer diagnosis. The current data provide evidence that tumor STK11/LKB1 loss of function is a driver of CC, simultaneously serving as a genetic biomarker for this wasting syndrome.

ACR Appropriateness Criteria® Routine Chest Imaging.

Routine chest imaging has been used to identify unknown or subclinical cardiothoracic abnormalities in the absence of symptoms. Various imaging modalities have been suggested for routine chest imaging. We review the evidence for or against the use of routine chest imaging in different clinical scenarios. This document aims to determine guidelines for the use of routine chest imaging as initial imaging for hospital admission, initial imaging prior to noncardiothoracic surgery, and surveillance imaging for chronic cardiopulmonary disease. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

ACR Appropriateness Criteria® Preprocedural Planning for Transcatheter Aortic Valve Replacement: 2023 Update.

This document discusses preprocedural planning for transcatheter aortic valve replacement, evaluating the imaging modalities used in initial imaging for preprocedure planning under two variants 1) Preintervention planning for transcatheter aortic valve replacement: assessment of aortic root; and 2) Preintervention planning for transcatheter aortic valve replacement: assessment of supravalvular aorta and vascular access. US echocardiography transesophageal, MRI heart function and morphology without and with IV contrast, MRI heart function and morphology without IV contrast and CT heart function and morphology with IV contrast are usually appropriate for assessment of aortic root. CTA chest with IV contrast, CTA abdomen and pelvis with IV contrast, CTA chest abdomen pelvis with IV contrast are usually appropriate for assessment of supravalvular aorta and vascular access. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

ACR Appropriateness Criteria® Thoracoabdominal Aortic Aneurysm or Dissection: Treatment Planning and Follow-Up.

As the incidence of thoracoabdominal aortic pathology (aneurysm and dissection) rises and the complexity of endovascular and surgical treatment options increases, imaging follow-up of patients remains crucial. Patients with thoracoabdominal aortic pathology without intervention should be monitored carefully for changes in aortic size or morphology that could portend rupture or other complication. Patients who are post endovascular or open surgical aortic repair should undergo follow-up imaging to evaluate for complications, endoleak, or recurrent pathology. Considering the quality of diagnostic data, CT angiography and MR angiography are the preferred imaging modalities for follow-up of thoracoabdominal aortic pathology for most patients. The extent of thoracoabdominal aortic pathology and its potential complications involve multiple regions of the body requiring imaging of the chest, abdomen, and pelvis in most patients. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

PET/Computed Tomography: Laryngeal and Hypopharyngeal Cancers.

Treatment of laryngeal and hypopharyngeal tumors with surgery, radiation therapy, and chemotherapy is aimed at improving survival and preserving function. PET with fluorodeoxyglucose F 18 (18F FDG-PET)/computed tomography is the standard of care and an integral part of staging and treatment response assessment in patients with laryngeal and hypopharyngeal cancers. Knowledge of cross-sectional laryngeal and hypopharyngeal anatomy, expected patterns of tumor spread, and awareness of physiologic FDG uptake in head and neck structures is essential for accurate TNM staging. 18F FDG-PET/computed tomography is superior to anatomic imaging in identifying posttreatment local, regional, and distant tumor recurrence.

FDG PET/CT for Primary Staging of Lung Cancer and Mesothelioma.

Lung cancer is the leading cause of cancer-related mortality in the United States. Accurate staging at initial diagnosis determines appropriate treatment and is the most important predictor of survival. Since 2018, the 8th edition of the TNM staging system has been used to stage lung cancer based on local tumor extent (T), nodal involvement (N), and metastases (M). 18 F fluorodeoxyglucose (FDG) PET/CT, which combines functional and anatomic imaging, is the standard of care and an integral part of clinical staging of patients with lung cancer. Malignant pleural mesothelioma (MPM), the most common primary malignant pleural tumor affecting the pleura is staged with 8th edition of TNM staging for MPM. 18 F FDG PET/CT is indicated in select patients who are surgical candidates to identify locally advanced tumor, nodal metastases, or extrathoracic metastases, which may preclude surgery.

FDG PET/CT findings and post-treatment changes of COVID-19 pneumonia in a patient with lymphoma: A case report.

A 29-year-old male with a history of Hodgkin's lymphoma presented for evaluation of response to chemotherapy with positron emission tomography/computed tomography using fluorine-18-fluoro-2-deoxy-d-glucose (18F-FDG PET/CT). Follow-up 18F-FDG PET/CT imaging demonstrated resolution of previously noted FDG avid axillary lymphadenopathy. However, multiple opacities with increased FDG uptake were noted in the lungs bilaterally, which were suspicious for pulmonary infection, including viral pneumonia. The patient tested positive for coronavirus disease 2019 (COVID-19) virus infection by reverse transcription-polymerase chain reaction (RT-PCR). Additional cycles of chemotherapy were delayed until the patient became negative for COVID-19 virus infection on follow-up RT-PCR test 2 weeks later. The patient received two additional cycles of chemotherapy. Follow-up 18F-FDG PET/CT post chemotherapy demonstrated a decrease in the size of the previously seen mediastinal lymphadenopathy, reduction of FDG uptake by the previously seen mediastinal lymphadenopathy, and reduction of FDG uptake by the previously seen pulmonary opacities, at 2 months after COVID-19 diagnosis. The findings of this case report demonstrated the importance of recognition of pulmonary abnormalities caused by COVID-19 pneumonia on 18F-FDG PET/CT imaging for clinical management of patients with lymphoma.