Pretreatment Positron Emission Tomography with 18F-Fluorodeoxyglucose May Be a Useful New Predictor of Overall Prognosis Following Lenvatinib Treatment

BACKGROUND AND AIM

The aim of this study was to identify the utility of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) as a predictor of overall prognosis in patients with hepatocellular carcinoma treated with lenvatinib.

METHODS

Forty-eight consecutive patients who received lenvatinib treatment were reviewed. The oncological aggressiveness of tumors estimated using 18F-FDG-PET/CT was investigated by the analysis of progression-free survival (PFS), post-progression survival (PPS), and overall survival (OS). Multivariate analysis was used to identify potential confounders for OS during lenvatinib therapy.

RESULTS

Using the Modified Response Evaluation Criteria in Solid Tumors, a tumor-to-normal liver ratio (TLR) ≥2, indicating higher oncological aggressiveness in HCCs, was associated with a better objective response to lenvatinib than a TLR <2 (78 vs. 62%), resulting in a similar PFS (p = 0.751). Because of a significantly worse PPS, OS with a TLR ≥2 was poor compared to a TLR < 2 (p = 0.012). Multivariate analysis confirmed that a TLR ≥ 2 was associated with poor OS (hazard ratio, 2.709; 95% CI, 1.140-6.436; p = 0.024). Analysis of 24 patients who received a repeat 18F-FDG-PET/CT showed that daily changes expressed as ΔTLR × 103/day over the treatment course tended to be different among the types of subsequent treatment. A R0 resection and lenvatinib-TACE sequential therapy provided good disease control (median, -4.593 and -0.024, respectively) compared with other treatments (median, 5.278) (p = 0.075).

CONCLUSION

Lenvatinib has acceptable disease control regardless of estimated tumor differentiation. A high TLR (≥2) is a poor prognostic factor of OS following lenvatinib treatment, while ΔTLR × 103/day provides useful information of disease control status.

Usefulness of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Diagnosis of Infective Endocarditis in Patients With Adult Congenital Heart Disease

BACKGROUND

Infective endocarditis (IE) in patients with adult congenital heart disease (ACHD) remains a diagnostic challenge due to difficulties in detecting endocardial lesions by echocardiography. ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) has shown good diagnostic performance in prosthetic valve IE. This study aimed to assess its additional diagnostic value in ACHD-associated IE and to characterize its advantages.Methods and Results:Overall, 22 patients with ACHD and clinical suspicion of IE were retrospectively studied. ¹⁸F-FDG PET/CT was performed in addition to conventional assessment based on the modified Duke criteria. The final IE diagnosis was determined by an expert team during a 3-month clinical course, resulting in 18 patients diagnosed with IE. Seven patients (39%) were diagnosed with definite IE only by initial echocardiography. An ¹⁸F-FDG PET/CT assessment revealed endocardial involvement in the other 9 patients, resulting in the diagnosis of definite IE in 16 in total (88%). Right-sided endocardial lesions were more common (n=12, 67%) but rarely identified by echocardiography, whereas ¹⁸F-FDG PET/CT revealed right-sided lesions in 9 patients. A negative ¹⁸F-FDG PET/CT (n=7, 39%) assessment was associated with a native valve IE (71% vs. 0%). In 4 patients who were identified with not-IE, neither echocardiography nor ¹⁸F-FDG PET/CT detected any suspicious cardiac involvement.

CONCLUSIONS

In the diagnosis of ACHD-associated IE, characterized by right-sided IE, ¹⁸F-FDG PET/CT assessment should be useful.

Isolated Splenic Tuberculosis Masquerading as Disease Progression of Hodgkin's Lymphoma on Interim18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Scan

¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) scan is the imaging modality of choice in the management of lymphoma. However, 18F-FDG is a nonspecific tracer for tumoral metabolic activity and infective pathology, thus posing a challenge in accurate response assessment. Here, we present a case of Hodgkin's lymphoma, referred for staging PET/CT scan which showed FDG-avid disease in the mediastinum, and on interim ¹⁸F-FDG PET/CT in addition to the mediastinal mass lesion, a FDG-avid lesion was also noted in the spleen suggestive of disease progression. The biopsy report of the lesion was tuberculosis, which was masquerading as disease progression on interim ¹⁸F-FDG PET/CT.

Recurrent Renal Carcinoma with Solitary Intramedullary Spinal Cord Metastasis

We report a case of an elderly male who has undergone right radical nephrectomy for renal cell carcinoma (RCC). Six months later, he presented with gradually progressive low backache and mild lower limb weakness. 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET-CT) was done that revealed a suspected area of mild metabolic activity in the spinal cords at the L1–L2 vertebral level. Magnetic resonance imaging revealed intramedullary spinal cord metastasis (ISCM). Solitary ICSM is a rare presentation of RCC on FDG PET-CT, and only a few case reports exist in the literature. This case highlights that adequate clinical history and careful examination of the PET images may reveal it.

Bilateral renal involvement in diffuse large B-cell lymphoma on fluorodeoxyglucose positron emission tomography/computed tomography

Secondary renal involvement in patients with diffuse large B-cell lymphoma (DLBCL) is rare and associated with poor prognosis. We, hereby, described a case of a patient diagnosed with DLBCL, in whom bilateral renal involvement was detected on 18F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT). The patient received 4 courses of chemotherapy, and follow-up ¹⁸F-FDG PET/ CT revealed the complete resolution of the diffuse increased renal ¹⁸F-FDG uptake. Renal lymphoma is uncommon and ¹⁸F-FDG PET/CT is particularly useful for detecting extranodal involvement in DLBLC.

A case of pulmonary tumor embolism diagnosed with respiratory distress immediately after FDG-PET/CT scan

Acute distress immediately following an ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) scan is an exceedingly rare event. We report a case whose condition was suddenly deteriorated in the nuclear medicine laboratory, and whose diagnosis was confirmed by FDG-PET/CT. A 67-year-old woman with left renal cell carcinoma (RCC) suddenly complained of dyspnea and tachycardia just after undergoing FDG-PET/CT. PET/CT images showed increased FDG uptakes in the left renal vein, inferior vena cava, right atrium, and bilateral hila. She was diagnosed with a massive tumor embolism from the inferior vena cava to both pulmonary arteries, and urgently underwent tumor embolectomy. FDG-PET/CT was helpful for diagnosing the tumor embolism and differentiating it from bland thromboembolism in this patient with RCC.

The Diagnostic Capacity of Pre-treatment 18F-FDG PET/CT for Predicting the Extranodular Spread of Lymph Node Metastases in Patients with Oral Squamous Cell Carcinoma

The aim of this study was to evaluate the ability of pretreatment 90-min 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) to predict the extranodular spread of lymph node metastases in oral squamous cell carcinoma. We retrospectively reviewed the cases of 56 patients who underwent pretreatment 18F-FDG PET/CT and surgery with neck dissection. Maximum standardized uptake value, metabolic tumor volume, and total lesion glycolysis were measured for the 56 primary sites and maximum standardized uptake value was measured for 115 lymph node levels. Extranodular spread was present at 9 lymph node levels in 7 patients. Significant differences were found in metabolic tumor volume and total lesion glycolysis of the primary site, and in lymph node maximum standardized uptake value, between patients with and without extranodular spread (p<0.05). Combining primary site total lesion glycolysis and lymph node maximum standardized uptake volume at their respective optimal cutoffs, the sensitivity, specificity, and accuracy for predicting extranodular spread were 89%, 92%, and 92%, respectively. Pretreatment 18F-FDG PET/CT is useful for predicting extranodular spread in patients with oral squamous cell carcinoma. The combined use of primary site total lesion glycolysis and lymph node maximum standardized uptake value showed greater predictive value than either predictor singly.

Potential and Clinical Significance of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography for Evaluating Liver Cancer Response to Lenvatinib Treatment

BACKGROUND

The sensitivity of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) in hepatocellular carcinoma (HCC) is low; however, clinical evidence demonstrating its prognostic value in patients with HCC has recently been reported. This study aimed to assess the value of 18F-FDG-PET/CT as a tool for evaluating the response of HCC to lenvatinib treatment.

METHODS

We evaluated 11 consecutive patients with HCC diagnosed by dynamic CT or magnetic resonance imaging combined with 18F-FDG-PET/CT from April 2018 to December 2019. The tumor-to-normal liver ratio (TLR) of the target tumor was measured before and during the course of lenvatinib treatment with 18F-FDG-PET/CT (pre and post analysis, respectively), with a TLR ≥2 classified as PET-positive HCC. At the time of each evaluation, we also used the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1, the modified RECIST (mRECIST), and the tumor marker alfa-fetoprotein (AFP).

RESULTS

Of 11 patients, 3 (27%) and 8 (73%) had an objective response to lenvatinib treatment at the time of post-analysis by RECIST 1.1 and mRECIST, respectively. There were 3 (27%) and 7 (64%) patients with PET-positive HCC at the time of pre- and post-analysis, respectively. There was a significant correlation between the rates of change in AFP and TLR during lenvatinib treatment (r = 0.69, p = 0.019). Based on these results, we were able to perform liver resection on 4 patients with PET-positive HCC as conversion therapy. Three samples from these patients showed poorly differentiated tumors.

CONCLUSION

18F-FDG-PET/CT has potential as an evaluation tool for describing biological tumor behavior and reflecting disease progression, location, and treatment response. This modality may provide useful information for considering prognosis and subsequent therapy.

The prognostic significance of the 18F-fluorodeoxyglucose positron emission tomography/computed tomography in early-stage nonsmall cell lung cancer

Context

The prognostic criteria for early-stage nonsmall cell lung cancer (NSCLC) wait to be explored.

Aim

In this study, our aim was to evaluate the prognostic significance of the positron emission tomography/computed tomography (PET/CT) maximum standardized uptake value (SUV_max) value of the primary tumor in patients with a diagnosis of early-stage NSCLC who received surgical treatment.

Settings and Design

This was a multicenter retrospective design.

Materials and Methods

Patients who had been diagnosed with early-stage NSCLC and who underwent surgery for the condition were included in this study. The preoperative fluorodeoxyglucose (18F-FDG) PET/CT results of the patients were retrospectively accessed from their medical files. The disease-free survival (DFS) rates of patients who had SUV_max values above and below the determined cutoff value were compared.

Statistical Analysis Used

SPSS version 22 and Kaplan-Meier method were used for statistical analysis.

Results

A total of 92 patients were included in the study. The median age of the patients was 60 years (range: 36-79). The determined cutoff SUV_max value of the primary tumor was 13.6. A comparison of the DFS rates of the patients with an SUV_max value above and below 13.6 revealed a significant difference in patients with Stage I (22.9 months vs. 50.3 months; P = 0.02) and Stage II (28 months vs. 40.4 months; P = 0.04), Stage I + II (43.5 months vs. 26.1 months; P = 0,02), and Stage IIIA (14.7 months vs. 13.6 months; P = 0.92) NSCLC.

Conclusions

We found that in early-stage NSCLC patients, the SUV_max value of the primary mass in 18F FDG PET/CT was a prognostic indicator for the DFS rates.

The Utility of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Differentiated Thyroid Cancer Patients with Biochemical Recurrence and Negative Whole-Body Radioiodine Scintigraphy and Evaluation of the Possible Role of a Limited Regional Scan

Purpose of the Study

¹⁸F-Fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) is used in the management of recurrent differentiated thyroid cancer (DTC) patients presented with rising thyroglobulin (Tg) or anti-Tg antibody (Atg) levels and negative whole-body I-131 scan (WBS). We aimed to evaluate the utility of regional or limited PET/CT in a large population preset with variable Tg/(ATg) levels.

Materials and Methods

In a retrospective study, we analyzed 137 PET/CT done on DTC patients presented with raised Tg/Atg and negative WBS. Retrospective evaluation of other available clinical information was done.

Results

One hundred and thirty-seven patients aged 8-72 years (41 ± 17.7 years) were included in the study. Eighty-nine (64.9%) patients had positive findings on ¹⁸F-FDG PET-CT. It included thyroid bed recurrence, cervical, mediastinal lymphadenopathy, lung, and bone lesions. In addition, 36 patients had metabolically inactive lung nodules detected on CT. Serum Tg and female sex were the only predictors for a positive PET scan. In most (97.1%) of the patients, the disease was limited to the neck and thoracic region.

Conclusions

PET/CT is an excellent imaging modality for evaluating DTC patients presented with biochemical recurrence. It not only finds the disease in more than 80% of the patients but also detects distant metastatic disease, which precludes regional therapies. Lesions were noted mostly in the neck and thoracic region with very few distant skeletal metastases (4/137 patients). In most of the patients, routine vertex to mid-thigh imaging could be avoided.

Alternative volumetric PET pjmirometers for evaluation of breast cancer cases with 18F-FDG PET/CT imaging: Metabolic tumour volume and total lesion glycolysis

INTRODUCTION

We aimed to investigate the prognostic and clinical values of two volumetric PET pjmirometers used in conjunction with SUV_max at different thresholds in invasive ductal carcinoma (IDC).

METHODS

A total of 139 metastatic IDC BC who underwent 18F-FDG PET/CT imaging were included to study. MTV and TLG (40%, 50%, 60% and 70%) used in conjunction with primary tumour SUV_max . Nodal involvement, distant metastasis, ER, PR, Ki-67 expression and survival data evaluated by comparing FDG PET pjmirometers.

RESULTS

Mean ± SD SUV_max of lesions (n = 139) was 13.97 ± 9.21. Primary tumour 18F-FDG uptake associated increased tumour diameter (>2 cm), high Ki-67 (>15%) and distant organ metastasis (DOM) (P = 0.015, 0.005 and 0.016, respectively). There was significant association between molecular subtypes and SUV_max (P = 0.002). High MTV associated with tumour diameter (MTV 40-70%), axillary lymph node (ALN) diameter (MTV 40-70%), and distant nodal metastasis (DNM) (MTV 50-70%). High TLG associated with tumour diameter (TLG 40-70%), high Ki-67 (TLG 40-70%), ALN metastasis (TLG 40%), ALN diameter (TLG 40-70%) and DNM (TLG 40-70%). Median survival found shorter in DOM patients (P = 0.030, Log Rank = 0.110).

CONCLUSION

We think evaluation of MTV and TLG at different thresholds in addition to SUV_max would enhance diagnostic and prognostic value of 18F-FDG PET/CT, and thus contribute to disease management.

Role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography and magnetic resonance imaging in prediction of response to neoadjuvant chemotherapy in pediatric osteosarcoma

The aim of our study was to evaluate the role of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI) in prediction of response to neoadjuvant chemotherapy (NAC) in pediatric osteosarcoma (OS) patients compared to percentage of tumor necrosis after surgical excision of the tumor. Forty-six pediatric OS patients treated with neoadjuvant chemotherapy and surgery were underwent PET/CT and MRI before, after 3 cycles, and after the completion of neoadjuvant chemotherapy. Imaging parameters include maximum standardized uptake value (SUVmax1, 2, and 3), tumor liver ratio (TLR 1, 2, and 3), and MRI tumor volume (MRTV 1, 2, and 3) at initial assessment before starting NAC, after finishing three cycles and after finishing 6 cycles before tumor excision, respectively. Cutoff values of the PET/CT and MRI parameters were determined using receiver operating characteristic (ROC) curve analysis and percentage of tumor necrosis of postsurgical specimen. Fourteen patients were good responders (30.4%), with more than 90% tumor necrosis, while 31 patients were poor responders (67.4%). The results of one patient were missed. We noticed that higher sensitivity for detecting poor responders was detected by SUVmax3/1, TLR3/1, and MRTV2/1 ratio cutoff values, while higher specificity was detected by TRL2 and SUVmax3 cutoff values. ROC curve analysis of MRTV2/1 and MRTV3/1 ratio was fair in predicting poor responders. PET/CT parameters are capable of predicting histological response to NAC in OS patients with overall sensitivity and specificity higher than MRI parameters.

Paraganglioma of the carotid body and intrapericardium

A 65-year-old Japanese woman with an intrapericardial tumor and neck tumor was admitted to our hospital. Intrapericardial tumor had not been resected because of massive bleeding from the hypervascular tumor and its invasion into the pericardium, ascending aorta, and pulmonary artery. The neck tumor had been successfully resected, and paraganglioma was pathologically diagnosed. Abnormal accumulation in the intrapericardial tumor was seen with ¹²³I-metaiodobenzylguanidine scintigraphy. Moreover, gene mutation of succinate dehydrogenase type D was found. Finally, paraganglioma of the carotid body and intrapericardium was diagnosed. <Learning objective: Cardiac paraganglioma (PGL) and simultaneous carotid body and cardiac PGL is exceedingly rare. We experienced a case of intrapericardial tumor and carotid body tumor, evaluated by histological examination of the surgical specimen of the carotid body tumor and multimodal imaging including ¹²³I-metaiodobenzylguanidine scintigraphy, and genetic analysis of the succinate dehydrogenase gene. The final diagnosis was type 1 PGLs of both the carotid body and intrapericardium.>.

18F-fluorodeoxyglucose positron emission tomography/computed tomography in childhood metastatic epithelioid hemangioendothelioma of the liver: Altering the management plan

Hepatic epithelioid hemangioendothelioma (EHE) is an uncommon vascular tumor, primarily seen in 20-40 years of age. We report the case of a 14-year-old boy with EHE and distant metastases identified on 18F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT), leading to a change in the management plan. ¹⁸F-FDG PET/CT proved to be useful in identifying the rare sites of metastasis and planning further treatment.

Aggressive squamous cell carcinoma of the renal pelvis

Squamous cell carcinoma (SCC) of the renal pelvis is a particularly rare tumor that accounts for a minor portion of renal malignancies and is aggressive with an unfavorable prognosis. It is usually diagnosed after surgery and at advanced stages as it does not possess specific clinical and radiological properties. The pathological examination of a 38-year-old female patient who had undergone nephrectomy due to a nonfunctioning right kidney caused by long-standing staghorn calculus revealed moderately differentiated renal pelvis SCC invading the renal parenchyma. The patient who experienced severe lumbar pain in the second postoperative month presented lymphadenopathy, which could not be detected with ultrasonography but was diagnosed with ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸FDG PET/CT). The patient received systemic treatment following the early diagnosis and survived past the average survival time. It was concluded that in cases where SCC was diagnosed after nephrectomy, investigating metastasis with ¹⁸FDG PET/CT and initiating early systemic treatment in the presence of metastasis could contribute to survival.

Regressed coronary ostial stenosis in a young female with Takayasu arteritis: a case report

Background

Takayasu arteritis is a rare systemic vasculitis, which affects the aorta and its major branches, especially in young females. Diagnosis and treatment for Takayasu arteritis with coronary stenosis are important to prevent fatal complications. Immunosuppressive treatment such as corticosteroid is a common treatment for this condition. However, the effects of immunosuppressive treatment on inflammatory coronary stenosis caused by Takayasu arteritis remains unknown.

Case presentation

An 18-year-old female had chest oppression on effort and was referred to our hospital due to ST-segment depression in I, aV_L, and V_2–4 on electrocardiogram. Coronary angiography showed severe stenosis in the ostium of both the left main trunk and the right coronary artery. ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography showed isolated inflammation of the aortic root. She was diagnosed with Takayasu arteritis and treated with combined immunosuppressive treatment with corticosteroid and tocilizumab, which decreased the FDG uptake in the aortic root. Four months after initiation of the immunosuppressive treatment, coronary angiography showed regression of the coronary ostial stenosis. Coronary artery bypass surgery was considered, but the patient rejected invasive revascularization for coronary artery disease. She did not have chest oppression or ST-segment depression after the immunosuppressive treatment. She had no cardiac events for 6 months after discharge.

Conclusions

We described regressed coronary ostial stenosis in a young female patient with Takayasu arteritis. Immunosuppressive treatment might have a favorable effect on coronary ostial stenosis in Takayasu arteritis.

Adenoid Cystic Carcinoma of Buccal Mucosa: Role of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Detection and Biopsy of Pulmonary Metastases and Assessment of Treatment Response

Adenoid cystic carcinoma of the buccal mucosa has an increased propensity for recurrence and distant metastases. Due to the poor prognosis at late detection of distant metastases, it is advisable to keep a close follow-up. In the present case, ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography proved invaluable in the comprehensive workup of the patient, including detection of local recurrence, distant metastases, and in assessing treatment response.

Clinical value of 18 F-fluorodeoxyglucose positron emission tomography/computed tomography for interstitial lung disease and myositis in patients with dermatomyositis

¹⁸ F-Fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) is usually used to screen malignancy in patients with dermatomyositis (DM). Additionally, it is well known that FDG-PET/CT provides valuable information for evaluating the activity of several inflammatory diseases, such as sarcoidosis, atherosclerosis, inflammatory bowel disease and rheumatoid arthritis. Therefore, the objective of this study was to evaluate the clinical usefulness of FDG-PET/CT for the detection of inflammatory lesions and disease activity of both myopathy and interstitial lung disease (ILD) in DM patients. We measured the maximum standardized uptake value (SUVmax) in the muscles and lungs in 22 DM patients, and compared with magnetic resonance imaging (MRI) and high-resolution computed tomography (HRCT) findings in the same muscle and lung regions as well as with clinical findings. We found that the location of increased FDG uptake was nearly consistent with the region of ILD and myositis detected by HRCT or MRI, respectively. There was a significant positive correlation between lung HRCT score and SUVmax in each lung. Serum Krebs von den Lungen-6 levels also revealed significant positive correlation with total SUVmax of right and left lungs. Regarding FDG-PET/CT and myopathy, total SUVmax in the muscles was significantly correlated with serum cytokeratin levels. Our results suggest that FDG uptake (SUVmax) might be useful for not only the detection of malignant tumors, but also the evaluation of the location and activity of ILD and myositis in DM patients.

Role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in restaging and prognosis of recurrent melanoma after curative surgery

Malignant melanoma is a highly aggressive tumor and surgical resection is the primary treatment. However, the chances of recurrence are quite high despite complete resection. The aim of study was to evaluate the ¹⁸F-fluorodeoxyglucose(¹⁸F-FDG) positron emission tomography–computed tomography (PET/CT) in detection of recurrent melanoma after curative surgery and its prognostic value. Fifty-four melanoma patients (32 women) with prior primary lesion resection were evaluated with ¹⁸F-FDG PET/CT for clinically suspicious recurrent disease. The diagnostic accuracy of ¹⁸F-FDG PET/CT (visual interpretation as well as semi-quantitative parameter) was determined on the basis of subsequent imaging and clinical follow-up. Melanoma-specific survival and risk of progression (hazard ratio [HR]) were assessed using Kaplan–Meier method and Cox regression analysis. ¹⁸F-FDG PET/CT detected recurrent diseases in 36 (66%) patients including distant metastases in 13 patients and second synchronous malignancy in 2 patients. Overall, the sensitivity, specificity, positive predictive value, and negative predictive value of ¹⁸F-FDG PET/CT were 91.2%, 80.0%, 88.6%, and 84.2%, respectively, with area under the curve of 0.86 (95% confidence interval: 0.74–0.97; P < 0.05). Positive ¹⁸F-FDG PET/CT study was associated with a significantly shorter overall survival than negative study (30.8 ± 4.6 vs. 64.5 ± 6.9 months, P < 0.05). Apart from positive ¹⁸F-FDG PET/CT scan, maximum standardized uptake value (SUVmax) >2.7 and combination of both were independently associated with an increased risk of disease progression (HR = 7.72, 21.58, and 11.37, respectively; P < 0.05). ¹⁸F-FDG PET/CT showed enhanced diagnostic performance in patients with suspicious recurrent malignant melanoma leading to appropriate management. FDG positivity along with SUVmax >2.7 provides important prognostic value in predicting the survival outcomes and assessing the risk of disease progression.

Coexistence of Multiple Metastatic Lesions Showing Various Grades of Differentiation in a Single Patient with Neuroendocrine Tumor of Lung as Primary: A Combined Modality Approach of 68Ga-DOTANOC Positron Emission Tomography/Computed Tomography and 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Imaging

Neuroendocrine tumors (NETs) of gastrointestinal (GI) tract and lungs are a rare variety of tumors but given their indolent nature are quite prevalent. These tumors are mostly malignant in nature and are often diagnosed in advanced stages. GI tracts are the most common sites of NETs followed by lungs, thymus, and other less common sites being ovaries, testis, and hepatobiliary system. Nuclear medicine imaging modalities include ⁶⁸Ga-DOTANOC positron emission tomography/computed tomography (PET/CT) which is sensitive for low-grade NETs and ¹⁸F-fluorodeoxyglucose (FDG) PET/CT which is more valuable for high-grade NETs. However, intermediate-grade NETs are equally sensitive to both ⁶⁸Ga-DOTANOC PET/CT and 18F-FDG PET/CT.

Using 18F-fluorodeoxyglucose positron emission tomography/computed tomography to estimate the length of gross tumor and involvement of lymph nodes in esophagogastric junction carcinoma

Objective

To determine the optimal approach for estimating the length of gross tumor and involvement of the lymph nodes with ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in esophagogastric junction carcinoma (EGJC). The result was verified with pathologic examination.

Materials and Methods

Twenty patients with diagnosed and untreated EGJC were enrolled. The length of the gross tumor was measured using different approaches with PET/CT: Standardized uptake value (SUV) 1.5-5.5 in intervals of 1.0 and 10%-50% of maximum SUV (SUV_max) on ¹⁸F-FDG PET/CT in intervals of 10%. The results were expressed as L_1.0-L_5.0, and L_10%-L_50%, respectively. The pathological length of gross tumor (L_path) was calculated based on the shrinkage ratio of primary tumor. The measurable lymph nodes were measured on PET/CT preoperatively, labeled during operation, and examined for pathology.

Results

L_path was 6.87 ± 2.25 cm, L_30% and L_2.5 were 6.61 ± 1.76 cm and 7.56 ± 1.89 cm, respectively. L_30% was closer to L_path than other % SUV_max, L_2.5 was closer to L_path than other absolute SUV thresholds. The diagnostic performance of ¹⁸F-FDG PET/CT for lymph nodes was best at the cutoff SUV of 2.7, providing sensitivity of 70% and a specificity of 83.7% for detecting lymph node metastases.

Conclusions

The tumor length with 30% SUV_max as the threshold was closest to the actual pathological length of EGJC. The diagnostic efficiency of ¹⁸F-FDG PET/CT was best at the cutoff SUV_max of 2.7 for detecting lymph node metastases in EGJC.

Spontaneous Resolution of Idiopathic Panniculitis: Role of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Diagnosis and follow-up

We present the case of a-55-year-old female patient who presented with dry cough. High-resolution computed tomography chest revealed multiple nodules in both lungs. ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) was done to look for the unknown primary. It showed hypermetabolic bilateral lung nodules, subcutaneous nodules involving lower limbs, an intramuscular nodule, enlarged paratracheal, and right axillary nodes. There was no primary tumor seen. The biopsy of subcutaneous nodule revealed panniculitis with the foreign body granuloma. Follow-up scans after 6 and 9 months showed spontaneous resolution of all lesions except for few right axillary nodes. There was no active treatment given, and the patient remains asymptomatic on follow-up. Here, PET/CT played a role in excluding a primary tumor, guiding the biopsy, and follow-up.

Renal Manifestation of Birt-Hogg-Dubé Syndrome Depicted by 18F-fludeoxyglucose Positron Emission Tomography/Computed Tomography in a Patient with Hurtle Cell Thyroid Malignancy

Birt-Hogg-Dubé (BHD) syndrome is an autosomal dominant genetic disorder characterized by small papular skin lesions (fibrofolliculomas) causing susceptibility to kidney cancer, renal and pulmonary cysts, spontaneous pneumothoraces, and several noncutaneous tumors. We report a case of a 67-year-old woman, with a previous history of right hemithyroidectomy for adenomatous lesion. She presented with a swelling in the right thyroid bed that on subsequent biopsy revealed features of metastatic carcinoma. 18F-fludeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) performed for the detection of primary malignancy showed increased high-grade metabolic activity in the right supraclavicular soft tissue mass extending into the superior mediastinum. Moreover, on low-dose CT, there have been bilateral renal interpolar cortical lesions with mild metabolic activity. Given the fact that the right neck mass was highly unlikely to represent renal metastases in the absence of widespread metastatic disease, surgical excision of the right neck mass was performed. The histology of the mass was in keeping with hurtle cell thyroid carcinoma. In regard to renal lesions, bilateral partial nephrectomy was performed, which was consistent with chromophobe renal cell carcinoma, raising the suspicion of BHD that was confirmed by the subsequent genetic evaluation. It is well established that 18F-FDG PET/CT study is not an optimal modality for evaluation of renal lesions. However, careful assessment of the CT features in conjunction with the associated metabolic activity of the 18F-FDG PET component increases the diagnostic accuracy of PET/CT.

Unilateral Primary Adrenal Lymphoma: Uncommon Presentation of a Rare Disease Evaluated Using 18F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography

Primary adrenal lymphoma (PAL) is a relatively rare disease entity with only fewer than 200 cases reported till date. PAL frequently presents with bilateral adrenal involvement and shows male preponderance. We here present a case of PAL in a 65-year-old female with a relatively uncommon unilateral adrenal involvement. The present case depicts that ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography had decisive role in the treatment management of this patient suggesting its potential utility in the management of this rare disease.

18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Features in Locally Advanced Breast Cancer and Their Correlation with Molecular Subtypes

Purpose:

¹⁸F-Fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) is now recognized as a staging investigation for locally advanced breast cancer. This retrospective review of data was performed to correlate the maximum standardized uptake value (SUV_max) of the primary tumor with the molecular subtype of breast cancer.

Materials and Methods:

Patients with biopsy-proven, treatment naïve, Stage III breast cancer, for whom ¹⁸F-FDG PET/CT data and immunohistochemistry 4 was available were included in the study. Correlations were deduced between the SUV_max of primary tumor to the molecular subtypes.

Results:

Three hundred and two patients were included in the study. Fifty-two (17.2%) tumors were Luminal A (LA), 131 (43.4%) Luminal B (LB), 42 (13.9%) human epidermal growth factor receptor-2 enriched (HE), and 77 (25.5%) basal-like (BL). SUV_max of the primary tumor differed significantly between LA and other subtypes (SUV_max: LA Median 7.4, LB 11.65, HE 13.5, BL 15.35, P < 0.001). Estrogen receptor (ER) and progesterone receptor (PR) positivity were inversely correlated to the SUV_max of the primary (SUV_max: ER + Median 10.4, ER - 14.2, P < 0.001, PR + 9.65, PR − 13.9, P < 0.001). There was a strong positive correlation observed between Ki67 and SUV_max (Pearson Coefficient 0.408, P < 0.001). A SUV_max value of 9.65 was determined as a cutoff on receiver operating characteristic curve to differentiate between LA and other subtypes with a sensitivity of 92.3% and specificity of 70.6%.

Conclusions:

SUV_max of primary showed a statistically significant difference between LA subtypes when compared to other subtypes. However, there was overlap of values in each subgroup and thus ¹⁸F-FDG PET/CT cannot be used to accurately assess the molecular characteristics of the tumor.