Objective To compare between 18F-2-fluoro-2-deoxy-D-glucose PET/computerized tomography (18F-FDG PET/CT) and routine iliac bone marrow biopsy (BMB) in assessment of bone marrow infiltration (BMI) in Hodgkin lymphoma and diffuse large B-cell lymphoma (DLBCL) patients at initial presentation. Patients and methods A retrospective analysis of 138 patients (50 Hodgkin lymphomas, 88 DLBCLs). The study included 70 males and 68 females with median age of 43 years. All patients underwent 18F-FDG PET/CT and iliac crest BMB before treatment. Any focal or patchy FDG uptake in the bone marrow, superior-to hepatic uptake was interpreted as abnormal with or without corresponding CT changes. Treatment response was evaluated clinically with each cycle of chemotherapy, radiologically after three cycles and at the end of treatment. Results The overall diagnostic performance showed significant higher sensitivity of 18F-FDG PET/CT than that of BMB (73.9 versus 62.5%, P = 0.046), while the specificity was higher in BMB than in 18F-FDG PET/CT (100% in BMB versus 93.5% in 18F-FDG PET/CT). In Hodgkin lymphoma, sensitivity, negative predictive value (NPV) and accuracy were significantly higher in 18F-FDG PET/CT compared with BMB, being 87.5, 94.4 and 96% versus 50, 81 and 84% (P = 0.02, 0.03, 0.04, respectively). However, for DLBCL patients, almost comparable results were found between both tests in terms of sensitivity, NPV and accuracy (66.7, 83.9 and 81.8% versus 68.8, 84.9 and 88.6%, respectively). After PET/CT scan, 12 patients (8.6%) were upstaged to stage IV, eight of them were negative by BMB. Conclusion 18F-FDG PET/CT seemed to be an excellent diagnostic test in assessment of BMI at initial assessment and staging of Hodgkin lymphoma and DLBCL patients.

The aim of this study was to evaluate the additive value of 99mtechnetium methylene diphosphonate (99mTc-MDP) hybrid single-photon emission computed tomography/computed tomography (SPECT-CT) in the diagnosis of skull base osteomyelitis (SBO) compared to planar bone scintigraphy (PBS). This was a single institution; prospective study included 23 patients with otitis externa, clinically suspected of SBO, all of them were diabetic. Three-phase bone scintigraphy and SPECT/CT were performed to all patients. The imaging modalities which had the most equivocal results were PBS (9/23) followed by SPECT (3/23). No equivocal results were detected with CT or SPECT-CT. SPECT-CT had the highest sensitivity (100%) and highest accuracy (95.7%) in diagnosis of SBO, whereas, PBS showed the lowest sensitivity (50%) and lowest accuracy (52.2%). In this study, SPECT-CT considered the best modality for accurate localization of the site of SBO involvement, followed by CT. SPECT and planar BS were less accurate in this consideration. When comparing the sensitivity of planar BS, CT, SPECT and SPECT/CT, statistical significance difference was detected between planar BS and SPECT (P = 0.057), planar BS and SPECT/CT (P = 0.001), and between CT and SPECT/CT (P = 0.031). No statistically significant difference was detected between SPECT and SPECT/CT (P = 0.250), CT and planar BS (P = 0.125), and between CT and SPECT (P = 0.508) In conclusion, 99Tc-MDP SPECT/CT has high sensitivity in the diagnosis of SBO and also provide accurate localization of the site of SBO.

Objective:To compare between Gates GFR measurement using 99m Tc DTPA scintigraphy (in vivo method)

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.

AIM:To correlate between the radionuclide in vitro plasma sampling method (using single and dual blood samples) and Gates’ GFR measurement using Tc-99m diethylene triamine penta-acetic acid (Tc-99m DTPA) renal scintigraphy (in vivo method).METHODS:This study included 40 renal donors (group 1) and 40 patients with obstructive uropathy (group 2). Group 1 included 22 males and 18 females with an age range from 22 to 65 years, while group 2 included 24 males and 16 females with age range 27 to 64 years. Both groups subjected to renal Scintigraphy after administration of 5 mCi 99m-Tc DTPA, GFR was calculated using Gates’ method (in vivo method), then plasma sampling was acquired at 60 mins and 180 mins post-injection of the tracer, samples were counted in well counter and GFR was calculated using in vitro technique either using single plasma sample (SPSM 60 mins) or dual sample (DPSM 60 & 180 min). Additionally, GFR was measured by estimated equations based on serum creatinine.RESULTS:In group 1, the mean GFR using in vivo Gates’ method was 115.7 ± 29 ml/min, while using the SPSM was 100.1 ± 16.1 ml/min, and the DPSM was 100.3 ± 20.1 ml/min. In group 2, mean GFR using in vivo method was 74.1 ± 14.5 ml/min, while using in vitro SPSM it was 77.5 ± 24.9 ml/min and DPSM was 76.8 ± 24.8 ml/min. There was no significant difference between mean GFR values using in vivo and in vitro methods (single or dual samples) in group 1 and 2 (p > 0.05). There is high significant correlation between SPSM and DPSM in groups 1 and 2 (r = 0.90, r = 0.91 respectively), moderate significant correlation was found between in vivo Gates’ method and in vitro SPSM in group 1 and 2 (r = 0.46 and 0.57 respectively) and moderate correlation was evident between in vivo and in vitro DPSM in both groups (r = 0.42 and 0.68 respectively). By using the DPSM as the reference standard significant high correlation was found with SPSM and significant-high moderate correlation with in vivo Gates’ scintigraphic method. Conclusion: In vitro plasma sampling considered as a reliable, accurate |method for GFR calculation yet it considered relatively complex, both single and dual sample in vitro techniques showed a very high correlation, and hence SPSM can replace DPSM.CONCLUSION:Renal scintigraphy and GFR estimation using Gates’ in vivo method is considered inaccurate, yet given its simplicity in performance it can still be used if corrected GFR is standardised for Egyptian population-based on studies with large numbers of patients from multiple centres.