Evaluation of Positron Emission Tomography and Contrast-Enhanced Computed Tomography Scan in Nodal Staging of Early Operable Uterine Cancers.

INTRODUCTION: In early operable stages of cervical an endometrial malignancies, surgical staging of lymph nodes is advocated as contrast-enhanced computed tomography (CECT) has limited sensitivity and accuracy. Although fluorine-18 (F-18) fluorodeoxyglucose (FDG)/positron emission tomography (PET)-CT has potential to identify subcentimeter-sized nodal metastases, higher prevalence of pelvic inflammatory disease in developing countries could result in lower accuracy. The present study was undertaken to assess the incremental value of PET scan over CECT for nodal staging before radical surgery. METHODS: Forty-four patients with the International Federation of Gynecology and Obstetrics (FIGO) Stage IA2-IIb carcinoma cervix and 28 patients of FIGO Stage I-II carcinoma endometrium underwent F-18 FDG-PET-CECT scan. A SUVmax value >2.5 g/ml based on body weight was considered as positive. An enhancing node with >1 cm size in the shortest dimension, with loss of fatty hilum was considered positive on CT images. The histological findings were considered the gold standard against which the two modalities were compared. RESULTS: All 1226 pelvic nodes were dissected, of which 65 were found to be metastatic (i.e., 5.3%). Of the 72 patients, 15 (20.83%) had pelvic nodal metastases. The overall accuracy of PET and CECT for assessment of pelvic nodal metastases was comparable (i.e., 86% vs. 85%). CONCLUSION: PET and CECT scans have similar accuracy in pelvic nodal staging of operable uterine malignancies. Granulomatous inflammation may not be a major cause of false-positive results. The sensitivity and negative predictive values are not high enough to obviate need of surgical nodal staging.

Impact of the activity calculation method used in transarterial radioembolization: a dosimetric comparison between 90Y-SIRSphere and 90Y-TheraSphere therapy.

PURPOSE: Transarterial radioembolization is used to treat primary and secondary liver malignancies. Two commercially available drugs are utilized for the purpose. The aim of our study is to compare the radiation dose delivered to the tumor by these drugs. MATERIALS AND METHODS: This study included 86 patients (M : F - 7.6 : 1, median age=50.5 years), 46 patients were treated by Y-TheraSphere and 42 patients were treated by Y-SIRSphere. Activity administered in Y-TheraSphere and Y-SIRSphere was calculated using a modified partition model and a modified body surface area model, respectively. The radiation dose delivered by two drugs was calculated and compared in our study. RESULT: Activity administered in Y-TheraSphere was significantly higher than that of Y-SIRSphere. Hence, the radiation dose delivered to the tumor by Y-SIRSphere was significantly lower (58.4%) than that of Y-TheraSphere (P=0.000). CONCLUSION: As the radiation dose delivered by Y-SIRSphere was lower than Y-TheraSphere, we believe that the formula for Y-SIRSphere activity calculation needs to be modified so that the optimal dose can be delivered to the tumor.

A case of Hepatitis E in a blood donor.

The threat of hepatitis E is being felt in blood banks in recent times. The disease is usually self-limiting, but may progress to a fulminant fatal form. We report a unique case of a hepatitis E virus (HEV)-positive asymptomatic blood donor who later developed jaundice and informed the blood bank. A blood donor passed all eligibility criteria tests and donated blood. After 20 days, the blood bank was informed by the donor that he had developed vomiting and jaundice 1 day postdonation. He was investigated by a local laboratory 1 day postdonation for liver profile, which was high. There had been a major outbreak in his community of similar symptoms during the same period. HEV IgM antibody by enzyme-linked immunosorbent assay was positive. Silent infections may be lurking in apparently healthy donors. Donors need to be encouraged to revert in case of any significant developments after donation and maintain open channels of communication.

90Y microsphere therapy: does 90Y PET/CT imaging obviate the need for 90Y Bremsstrahlung SPECT/CT imaging?

BACKGROUND: Transarterial radioembolization using Y microspheres is a novel therapeutic option for inoperable hepatic malignancies. As these spheres are radiolucent, real-time assessment of their distribution during the infusion process under fluoroscopic guidance is not possible. Bremsstrahlung radiations arising from 90Y have conventionally been used for imaging its biodistribution. Recent studies have proved that sources of 90Y also emit positrons, which can further be used for PET/computed tomography (CT) imaging. This study aimed to assess the feasibility of 90Y PET/CT imaging in evaluating microsphere distributions and to compare its findings with those of Bremsstrahlung imaging. MATERIALS AND METHODS: Thirty-five sessions of 90Y microsphere transarterial radioembolization were performed on 30 patients with hepatic malignancies. 90Y PET/CT imaging was performed within 3 h of therapy. Bremsstrahlung imaging was also performed for each patient. The imaging findings were compared for concordance in the distribution of microspheres. RESULTS: Exact one-to-one correspondence between 90Y PET/CT imaging and 90Y Bremsstrahlung imaging was observed in 97.14% of cases (i.e. in 34/35 cases). Discordance was observed only in one case in which 90Y PET/CT imaging resolved the microsphere uptake in the inferior vena cava tumor thrombus, which was, however, not visualized on Bremsstrahlung imaging. CONCLUSION: There is good concordance in the imaging findings of 90Y PET/CT and 90Y Bremsstrahlung imaging. 90Y PET/CT imaging scores over the conventionally used Bremsstrahlung imaging in terms of better resolution, ease of technique, and comparable image acquisition time. This makes it a preferred imaging modality for assessment of the distribution of 90Y microspheres.

Comparative analysis of hepatopulmonary shunt obtained from pretherapy 99mTc MAA scintigraphy and post-therapy 90Y Bremsstrahlung imaging in 90Y microsphere therapy.

INTRODUCTION: (99m)Tc macroaggregate albumin (MAA) scintigraphy is routinely used to estimate the hepatopulmonary shunt (HPS) of (90)Y microspheres because of their comparable average particle sizes (20-30 µm). However, the MAA particle size can vary from 10 to 90 µm. Therefore, HPS computed from (99m)Tc MAA scintigraphy may not accurately represent the HPS of (90)Y microspheres. In view of this, the present study was undertaken to investigate the accuracy of (99m)Tc MAA scintigraphy in estimating the HPS of (90)Y microspheres. MATERIALS AND METHODS: Nineteen sessions of transarterial radioembolization using (90)Y therasphere were carried out in 17 patients for hepatic malignancies (both primary and secondary). For each session of therapy, a pretherapeutic (99m)Tc MAA scintigraphy and post-therapeutic (90)Y Bremsstrahlung scintigraphy were performed. The HPSs obtained from these images were compared. RESULTS: The mean HPS fractions calculated from the pretherapeutic (99m)Tc MAA study and the post-therapeutic (90)Y Bremsstrahlung images were 4.77 ± 2.81 and 4.52 ± 2.5%, respectively. The coefficient of correlation (r) was 0.96. CONCLUSION: (99m)Tc MAA scintigraphy accurately predicts the HPS of (90)Y microspheres.

Therapeutic response to radiofrequency ablation of neoplastic lesions: FDG PET/CT findings.

Ablation of neoplastic lesions by using radiofrequency energy is gaining popularity in clinical practice because of the minimally invasive nature of radiofrequency ablation (RFA). Primary and secondary tumors of the liver and lung are treated with RFA when surgery is precluded because of comorbidity. Benign bone tumors are also treated with RFA to relieve pain and prevent further tumor growth. Differentiation between postablation tissue changes and residual disease is difficult with morphologic imaging modalities such as ultrasonography, computed tomography (CT), and magnetic resonance (MR) imaging, thus limiting the use of these modalities to detection of residual disease early after RFA. Fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) is a functional imaging modality that can be used to study the effects and efficacy of RFA. Lesions that show increased FDG uptake at PET become completely photopenic immediately after RFA, a finding that is suggestive of the completeness of ablation. Focal areas of increased FDG uptake within the ablated zone are suggestive of residual disease. Reactive tissue changes such as inflammation are depicted in the periphery of the ablated lesion and show a uniform low-grade FDG uptake, which can be differentiated from the focal, nodular intense uptake in areas of residual disease. Use of combined FDG PET/CT to detect residual disease early after RFA allows ablation to be repeated, if necessary, to obtain the maximum therapeutic benefit. Note that FDG uptake in the complications sometimes associated with RFA can be a cause of potential false-positive PET results.

Splenic mass and isolated gastric varices: a rare presentation of a neuroendocrine tumor of the pancreas.

CONTEXT: Splenic involvement in neuroendocrine pancreatic tumors is well known but rarely presents as a primary splenic mass. CASE REPORT: A rare case of a neuroendocrine tumor involving the tail of the pancreas, splenic hilum and splenic flexure of the colon, forming a conglomerate mass and presenting as isolated gastric varices is described. A 75-year-old male presented with hematemesis and melena. Esophagogastroduodenoscopy revealed isolated gastric varices. A CT scan revealed a mass predominantly involving the spleen and a small part of the pancreas. CONCLUSION: A splenic mass with isolated gastric varices should be kept in mind as one of the presentations of a pancreatic neuroendocrine tumor.