Lesion Analysis in PERCIST 1.0: Clinical Ease versus Research Requisite-Where Does the Balance Exist?

Background Semiqualitative parameter SUVmax has been the most frequently used semiquantitative positron emission tomography (PET) parameter for response evaluation, but only metabolic activity of a single (most metabolic) lesion is predicted. Newer response parameters such as tumor lesion glycolysis (TLG) incorporating lesions' metabolic volume or whole-body metabolic tumor burden (MTBwb) are being explored for response evaluation. Evaluation and comparison of response with different semiquantitative PET parameters such as SUVmax and TLG in most metabolic lesion, multiple lesions (max of five), and MTBwb in advanced non-small cell lung cancer (NSCLC) patients were made. The different PET parameters were analyzed for response evaluation, overall survival (OS), and progression-free survival (PFS). Methods 18 F-FDG-PET/CT (18-fluorine-fluorodeoxyglucose positron emission tomography/computed tomography) imaging was performed in 23 patients (M = 14, F = 9, mean age = 57.6 years) with stage IIIB-IV advanced NSCLC before initiation of therapy with oral estimated glomerular filtration rate-tyrosine kinase inhibitor for early and late response evaluation. The quantitative PET parameters such as SUVmax and TLG were measured in single (most metabolic) lesion, multiple lesions, and MTBwb. The parameters SUVmax, TLG, and MTBwb were compared for early and late response evaluation and analyzed for OS and PFS Results No significant difference in change in response evaluation was seen in patients evaluated with most metabolic lesion, multiple lesions, or MTBwb. Difference in early (DC 22, NDC 1) and late (DC 20, NDC 3) response evaluation was seen that remained unchanged when lesions were measured in terms of number of lesions or the MTBwb. The early imaging was seen to be statistically significant to the OS compared with late imaging. Conclusions Single (most metabolic) lesion shows similar disease response and OS to multiple lesions and MTBwb. Response evaluation by late imaging offered no significant advantage compared with early imaging. Thus, early response evaluation with SUVmax parameter offers a good balance between clinical ease and research requisition.

Crossed Cerebellar Diaschisis in Thalamic Lymphoma on 18 F-FDG PET/CT.

Primary central nervous system lymphomas (PCNSLs) are extranodal variant forms of non-Hodgkin lymphoma arising within the brain parenchyma, leptomeninges, or spinal cord. PCNSL can present with varied neurological symptoms and imaging findings, making diagnosis without biopsy difficult. PCNSLs are highly aggressive, causing rapid deterioration, but are responsive to chemotherapy and radiotherapy making early diagnosis important. Crossed cerebellar diaschisis (CCD) is mostly seen with cerebral cortex vascular insults and is rarely reported with thalamic lesions and even rarer with thalamic lymphoma. However, CCD has also been described in other brain tumors (including primary glioma), chronic subdural hematoma, congenital insults, intracranial infections, and various dementia subtypes. We present a rare case of thalamic lymphoma evaluated with positron emission tomography/computed tomography that showed hypermetabolism of thalamus and associated hypometabolism in ipsilateral cerebral cortex and contralateral cerebellum representing CCD.

123-Iodine MIBG in the Assessment of Sympathetic Denervation in Ogilvie's Syndrome.

123-Iodine metaiodobenzylguanidine (I-123 MIBG) imaging is frequently used in the assessment of sympathetic innervation and autonomic dysfunction in patients with cardiac failure, neurodegenerative Parkinson's syndrome, multiple system atrophy, myotonic dystrophy, and diabetic mellitus. The etiology of pseudo-obstruction remains unknown with likely imbalance between sympathetic and parasympathetic innervation proposed as a hypothesis. We present a case demonstrating the utility of I-123 MIBG scintigraphy for evaluating a case of pseudo-obstruction requiring frequent hospitalization due to progressive complex autoimmune neurological disorder.

Factors Influencing Outcome Post-Radium-223 Dichloride in Castrate Resistant Prostate Cancer: A Review of Some Real-World Challenges.

Aim Radium-223 has been the first-approved targeted Alpha therapy agent. We retrospectively assessed different factors influencing the overall survival (OS) and patient management. Setting and Design Thirty-two metastatic castration-resistant prostate cancer (mCRPC) patients' hematological parameters, number of cycles, performance status, and toxicities were evaluated for OS. Radium 223 dichloride (Radium-223) was administered every 4 weeks for a maximum of six cycles. Primary and secondary end points were OS, progression free survival (PFS), therapy toxicities, change in performance status, biochemical response, and skeletal-related events (SREs). Materials and Methods Patients' median age was 77 years (range: 57-90 years) and median follow-up was 399 days (range: 5-1,761 days). A total of 163 cycles were administered in 32 patients, with 4 or less cycles in 8 patients (25%) and 5 or more cycles in 24 patients (75%). Among eight patients with 4 or less cycles, three patients died, of which two patients died due to neutropenic sepsis. Statistical Analysis Mann-Whitney test was used to compare the cycle groups; Spearman's correlation coefficient was used to see the relation of different variables with OS. Log rank test was used for group comparison while Kaplan-Meier survivorship was used for OS. Results Statistical correlation was seen between the number of cycles ( p =0.037) and hemoglobin ( p =0.028). Kaplan-Meier OS ( p =0.038) was correlated with the number of cycles (≤ 4 cycles and ≥ 5 cycles). OS was 173 days in patients with one to four cycles, 226 days in five cycles, and 493 days in six cycles. Myelosuppression leading to stopping of full six cycles was seen in 7 of 32 patients (22%) and significantly correlated to inferior OS ( p =0.048). Conclusion Higher number of Radium-223 cycles was seen to be associated with better OS. Prior myelosuppression was associated with poor OS. Patients with better hematological profile were more likely to complete the maximum number of the cycles with a better OS.

Indeterminate skeletal and lymph node lesion on 18F PSMA 1007 PET/CT scanning: lessons from a review at 12 months with PSMA-RADS.

AIMS OF THE STUDY: The study utilizes the prostate-specific membrane antigen-reporting and data system (PSMA-RADS) version 1.0 in a real-world patient scenario in the evaluation of equivocal lesions using the PSMA-RADS categorization for patient management and communication in multidisciplinary team (MDT) meetings. METHODS: A retrospective analysis of 203 patients who had 18F PSMA PET/CT for either restaging or staging over 12 months was undertaken. The scans were evaluated for local disease, lymph node involvement and distant metastases. The scan findings were classified as suspicious for metastases, and equivocal and benign lesions. Experience with PSMA ligand imaging was considered while classifying the lesions, equivocal lesions were assessed with PSMA-RADS and followed up with complementary imaging and/or clinical follow-up assessment or MDT for further patient management. RESULTS: A total of 91 of 203 patients had equivocal lesions. Follow-up assessment was performed in 47 of 91 patients with imaging ( n = 36) or MDT discussion ( n = 11).On follow-up imaging ( n = 36), equivocal lesion was seen in skeletal lesions ( n = 24), pelvic lymph nodes ( n = 6), both skeletal and pelvic nodes ( n = 4), hilar and mediastinal lymph nodes ( n = 1) and spleen ( n = 1). The patients were reclassified as benign, metastatic with few lesion remained equivocal. Overall follow-up assessment impacted clinical management in 47% patients. CONCLUSION: 18F PSMA PET/CT may show equivocal lesions; many of them in the skeleton, a small proportion of which are ultimately proven metastatic. In contrast, a higher proportion of the equivocal nodes in the pelvis end up being metastatic on follow-up. A structured reporting with PSMA-RADS grading helps in the proper classification of lesions and standardization of reports.

Role of 18F-flurodeoxyglucose in orthopaedic implant-related infection: review of literature and experience.

Infection and inflammation are a common occurrence with orthopaedic procedures. Anatomical modalities can show the transformation in the disease process; however, these may occur later when compared with functional imaging modalities that are more likely to identify early disease patterns. Various molecular imaging modalities such as three-phase bone scintigraphy, labelled leucocyte scintigraphy, as well as radiolabelled antibiotics and immunoglobulins have been considered and have played key roles in assisting clinical decision-making. While 18F-flurodeoxyglucose (FDG) PET/computed tomography (CT) has been relatively well established in cancer pathways, it has the potential to contribute to surgical decision making for possible osteomyelitis post-metal implant surgery. In this article, we present a review of recently used tracers, and share our experience with using 18F-FDG PET/CT studies in a few diverse clinical settings related to post-metal implant osteomyelitis.

Role of 18F-FDG PET/CT in infection of cardiovascular implantable electronic devices: review of the literature and initial experience.

Infections involving cardiovascular implantable electronic devices are becoming increasingly common, and increasingly complex to manage. Advances in technology have made implantable electronic devices smaller, and easier to implant, and patients are now also more likely to be older, with more complex comorbidities. Infections related to these devices are, however, not decreasing, and in some settings, these are rising. There is a clinical need for more accurate tests for confirming or ruling out infected devices. In this article, we review the relevant literature and share our own initial experience.

F-18 fluorodeoxyglucose positron emission tomography/computed tomography in a rare case of recurrent malignant mixed mullerian tumor.

We report a case of 66-year-old female with previous history of histopathologically proven. Malignant mixed mullerain tumor of the uterus in whom positron emission tomography/computed tomography (CT) done for characterization of soft tissue lesion in pelvis noticed on CT, showed extensive recurrent disease in the pelvis with pulmonary metastases.

Can 3'-deoxy-3'-(18)F-fluorothymidine or 2'-deoxy-2'-(18)F-fluoro-d-glucose PET/CT better assess response after 3-weeks treatment by epidermal growth factor receptor kinase inhibitor, in non-small lung cancer patients? Preliminary results.

The objectives of this study was to study the diagnostic efficacy of 3'-deoxy-3'-fluorine-18-fluorothymidine ((18)F-FLT) and of 2'-deoxy-2'-(18)F-fluoro-d-glucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) for response evaluation following three weeks treatment by epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) in non small cell lung cancer (NSCLC) patients. Fifteen patients of advanced stage (IIIB-IV) NSCLC planned for oral 1st or 2nd/3rd line EGFR-TKI treatment were enrolled in the study. Baseline, prior to treatment, and follow-up after three weeks, (18)F-FLT and (18)F-FDG PET/CT imaging was performed in all patients. The standard uptake lean body mass (SULpeak) and total lesion glycolysis (TLG) values of the hottest lesions were calculated in all patients using semi-quantitative analysis. Statistical analysis on PET semi-quantitative data was used to evaluate the overall survival (OS) and progression free survival (PFS). The patients were either classified as responders or non-responders or at a steady state according to the PET response criteria in solid tumors (PERCIST). The receiver operating characteristic curve (ROC) analysis was done on the (18)F-FDG PET/CT clinical responders, to derive the cut-off values on the corresponding data sets between responders and non responders. Results showed that in responders (18)F-FDG SULpeak values better predicted OS and PFS values when compared to (18)F-FLT SULpeak values and also were a better predictor of OS as compared to the TLG values. In responders, the ROC analysis carried out on (18)F-FLT PET/CT imaging data in responders indicated a decrease of ≥22% in SULpeak and a decrease of ≥0.7 in absolute values. Three (3/15) patients developed resistance to EGFR-TKI treatment at 3 months of follow-up. In conclusion, in both responders and in non responders, patients with NSCLC treated for 3 weeks by EGFR-TKI, both OS and PFS were better predicted by (18)F -FDG SULpeak than by (18)F -FLT SULpeak. Although, the difference was only borderline, yet, (18)F -FDG SULpeak was a better predictor of OS compared to TLG values. However, to validate these findings, studies need to be carried in a larger number of patients.

Role of 18F-FDG PET/CT in identifying distant metastatic disease missed by conventional imaging in patients with locally advanced breast cancer.

OBJECTIVES: This study was conducted to evaluate the role of (18)F-fluorodeoxyglucose ((18)F-FDG) PET/computed tomography (CT) in identifying missed distant metastases in patients with locally advanced breast cancer (LABC) who were assessed by conventional imaging methods. MATERIALS AND METHODS: Forty-three consecutive patients with histopathologically proven LABC with negative conventional imaging results for distant metastases were included in the study. All of them underwent (18)F-FDG PET/CT within a week after conventional imaging. RESULTS: (18)F-FDG PET/CT findings suggestive of distant metastases were noted in 11/43 patients, and 10 of them were confirmed to have true-positive distant metastatic disease on clinical follow-up of 6 months. None of the patients with negative (18)F-FDG PET/CT for distant metastases developed distant metastases during the follow-up. (18)F-FDG PET/CT had a sensitivity, specificity, positive predictive value, and negative predictive value of 100, 96.8, 91, and 100%, respectively, for identifying distant metastases missed by conventional imaging. In addition, (18)F-FDG PET/CT suggested previously unknown lymph nodal metastases in 16/43 (37%) patients. Change in stage was noticed in 17/43 (39.5%) patients. CONCLUSION: (18)F-FDG PET/CT is a sensitive and specific imaging modality for identifying distant metastases in patients with LABC missed by conventional imaging. In addition, it detects unknown lymph nodal metastases in a significant proportion of patients and hence can be used routinely in staging of patients with LABC.

Renal cell carcinoma presenting as isolated deltoid muscle metastasis 12 years after radical nephrectomy detected on 18F-FDG PET/CT.

We report a case of renal cell carcinoma detected to have isolated deltoid metastasis on 18F-FDG PET/CT 12 years after radical nephrectomy. Isolate muscle (deltoid) metastasis from renal cell carcinoma has not been reported in the literature.

(99m)Tc-pertechnetate scintigraphy and endoscopy in assessment of caustic-induced gastric mucosal injury.

Endoscopy is the gold standard for evaluating caustic-induced gastric mucosal injury. Injuries ≥ 2b (confluent ulceration or charring) are associated with perforation and cicatrisation. Grade 1-2a injuries recover without intervention. Grade 2b and 3 injuries require observation and may need intervention. (99m)Tc-pertechnetate imaging can assess gastric viability after caustic injury. We correlated (99m)Tc-pertechnetate SPECT/CT with endoscopic findings in 4 patients with increasing grades of caustic-induced gastric mucosal injury.

Factors predicting treatment failure in patients treated with iodine-131 for graves' disease.

Treatment of Graves' disease with iodine-131 ((131)I) is well-known; however, all patients do not respond to a single dose of (131)I and may require higher and repeated doses. This study was carried out to identify the factors, which can predict treatment failure to a single dose of (131)I treatment in these patients. Data of 150 patients with Graves' disease treated with 259-370 MBq of (131)I followed-up for at least 1-year were retrospectively analyzed. Logistic regression analysis was used to predict factors which can predict treatment failure, such as age, sex, duration of disease, grade of goiter, duration of treatment with anti-thyroid drugs, mean dosage of anti-thyroid drugs used, (99m)Tc-pertechnetate ((99m)TcO4 (-)) uptake at 20 min, dose of (131)I administered, total triiodothyronine and thyroxine levels. Of the 150 patients, 25 patients required retreatment within 1 year of initial treatment with (131)I. Logistic regression analysis revealed that male sex and (99m)TcO4 (-) uptake were associated with treatment failure. On receiver operating characteristic (ROC) curve analysis, area under the curve (AUC) was significant for (99m)TcO4 (-) uptake predicting treatment failure (AUC = 0.623; P = 0.039). Optimum cutoff for (99m)TcO4 (-) uptake was 17.75 with a sensitivity of 68% and specificity of 66% to predict treatment failure. Patients with >17.75% (99m)TcO4 (-) uptake had odds ratio of 3.14 (P = 0.014) for treatment failure and male patients had odds ratio of 1.783 for treatment failure. Our results suggest that male patients and patients with high pre-treatment (99m)TcO4 (-) uptake are more likely to require repeated doses of (131)I to achieve complete remission.

Hybrid single photon emission computed tomography/computed tomography sulphur colloid scintigraphy in focal nodular hyperplasia.

It is important to differentiate focal nodular hyperplasia (FNH), a benign condition of liver most commonly affecting women, from other neoplasm such as hepatic adenoma and metastasis. The functional reticuloendothelial features of FNH can be demonstrated by scintigraphy. We present a case of breast cancer in whom fluorodeoxyglucose positron emission tomography/computerized tomography (CT) showed a homogenous hyperdense lesion in liver, which on Tc99m sulfur colloid single-photon emission computed tomography/CT was found to have increased focal tracer uptake suggestive of FNH.

Role of F-18 fluorodeoxyglucose positron emission tomography/computed tomography in the detection of recurrence in patients with cervical cancer.

INTRODUCTION: Treatment of cervical cancer is usually surgery in the early stages and radiotherapy or chemoradiotherapy in more advanced stages of the disease. Recurrence may occur in multiple sites following primary treatment. Although recurrent metastatic disease is not curable, surgical treatment may be of great help if locoregional recurrence is detected early. Fluorine-18 Fluorodeoxyglucose positron emission tomography - computed tomography (F-18 FDG PET/CT) forms an important part of investigations in the diagnosis of clinically suspicious recurrent cervical cancer. OBJECTIVE: To assess the role of F-18 FDG PET/CT in diagnosing recurrence in patients with clinical suspicion of recurrent cervical cancer. MATERIALS AND METHODS: We retrospectively evaluated 53 histopathologically proved patients of cervical cancer. All the patients had been treated with either surgery/radiation therapy with or without chemotherapy. The standard PET/CT acquisition protocol, with delayed post void static pelvic images, wherever required, was followed in all patients. Significant uptake of FDG in the lymph nodes was considered to be a recurrence suggestive of metastasis. Para-aortic lymph nodal involvement was considered to be distant metastasis. Any significant uptake in the lung nodule on FDG PET was evaluated either by histological confirmation, by taking fine needle aspiration cytology (FNAC), or by a follow-up chest CT done after three months. RESULTS: Of the 53 patients with clinically equivocal recurrence, FDG PET/CT suggested recurrence in 41 patients (local recurrence in 14 patients and distant recurrence/metastasis with or without local recurrence in 27 patients). It had a sensitivity of 97.5%, a specificity of 63.6%, positive predictive value of 90.9%, and negative predictive value of 87.5%. CONCLUSION: PET/CT appears to have an important role in detecting recurrence following primary treatment of cervical cancer. The high positive and negative predictive values of PET/CT may be helpful in planning management of recurrent cervical cancer.

Is 68Ga-DOTATATE the answer in lung carcinoid? : Case report and review of literature.

Carcinoid tumors are rich in somatostatin receptors and show high uptake of radiotracer on octreotide scintigraphy. 68Ga-DOTATATE could be of great help at initial staging and during follow-up of these patients. We describe a patient with avid 68Ga-DOTATATE and poor F18-FDG uptake.

Methylene diphosphonate uptake in a case of vertebral hemangioma: demonstration with hybrid SPECT/CT.

Osseous hemangiomas are usually asymptomatic. Symptomatic hemangiomas are rare and represent approximately 1% of all cases. Hemangiomas usually present as photopenic defects in methylene diphosphonate (MDP) bone scintigraphy. MDP uptake in vertebral hemangiomas is extremely rare. We report a 20-year-old woman who presented with upper back pain. MDP bone scan showed focus of MDP uptake in the seventh dorsal vertebra. SPECT/CT localized the uptake to vertebral body and transverse process with CT findings suggestive of hemangioma. Further, MRI also confirmed hemangioma in the same location.