Evaluation of a 2D UNet-Based Attenuation Correction Methodology for PET/MR Brain Studies

Journal of Digital Imaging - Deep learning (DL) strategies applied to magnetic resonance (MR) images in positron emission tomography (PET)/MR can provide synthetic attenuation correction (AC) maps,...     

[11C]Choline PET/CT detection of bone metastases in patients with PSA progression after primary treatment for prostate cancer: comparison with bone scintigraphy

Purpose  

The aim of this study was to evaluate the clinical usefulness of [¹¹C]choline positron emission tomography (PET)/CT in comparison with bone scintigraphy (BS) in detecting bone metastases (BM) of patients with biochemical progression after radical treatment for prostate cancer (PCa).     

Imaging of a thymoma incidentally detected by C-11 choline PET/CT

The integrated modality positron emission tomography/computed tomography (PET/CT) with C-11 choline is an established diagnostic tool for restaging prostate cancer patients with a biochemical failure after primary treatment. Thymoma is a rare tumor originating in thymus epithelial cells, asymptomatic in one-third to one-half of patients, and often occurring in the fourth and fifth decades of life. In the present case, C-11 choline PET/CT was performed in a prostate cancer patient with a biochemical relapse, to restage the disease. In addition to the detection of local recurrent disease in prostatic fossa, an abnormal C-11 choline increased uptake in mediastinum was reported. The mediastinal finding was initially wrongly interpreted by clinicians as a lymph nodal metastasis from prostate cancer. However, histopathological analysis confirmed the presence of a thymoma. Although rare, thymoma has to be considered as differential diagnosis in case of mediastinal masses presenting C-11 choline PET/CT positive findings, to avoid inappropriate patient management.     

Role of 18FDG-PET/CT in detecting relapse during follow-up of patients with Hodgkin’s lymphoma

The role of ¹⁸FDG-PET/CT during follow-up of patients affected by Hodgkin’s lymphoma (HL) in complete remission after treatment is not fully elucidated, since a wide use of ¹⁸F fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸FDG-PET/CT) in this setting could be limited by a relative high rate of false-positive results. Herein, we summarize a retrospective analysis of 27 patients with Hodgkin’s lymphoma in complete remission after the first-line (n?=?20) or salvage (n?=?7) therapy receiving serial ¹⁸FDG-PET/CT scans during follow-up. Out of 165 scans, 13 were suspected for relapse, which was confirmed in seven patients. All relapses were correctly identified by ¹⁸FDG-PET/CT positivity, with a 100% sensitivity; false-positive rate was 46% and negative predictive value was 100%. True-positive findings were mostly associated with multiple sites, subdiaphragmatic involvement, and/or previous sites of disease. According to our results, we conclude that performing routine PET/CT scan during follow-up of those patients who are at high risk of relapse would be advisable, although caution must be adopted when interpreting PET/CT results due to the relatively high rate of false-positive findings. If FDG abnormal uptake is present at multiple nodal sites, subdiaphragmatic lymph nodes, or previous sites of disease, histological verification of PET abnormal findings is warranted.     

Early chemotherapy intensification with BEACOPP in advanced-stage Hodgkin lymphoma patients with a interim-PET positive after two ABVD courses

Interim 2-[18F]Fluoro-2-deoxy-D-glucose Positron Emission Tomography performed after two chemotherapy cycles (PET-2) is the most reliable predictor of treatment outcome in ABVD-treated Hodgkin Lymphoma (HL) patients. We retrospectively analysed the treatment outcome of a therapeutic strategy based on PET-2 results: positive patients switched to BEACOPP, while negative patients continued with ABVD. Between January 2006 and December 2007, 219 newly diagnosed HL patients admitted to nine centres were enrolled; 54 patients, unfit to receive this treatment were excluded from the analysis. PET-2 scans were reviewed by a central panel of nuclear medicine experts, according to the Deauville score (Meignan, 2009). After a median follow up of 34 months (12-52) the 2-year failure free survival (FFS) and overall survival for the entire cohort of 165 patients were 88% and 98%; the FFS was 65% for PET-2 positive and 92% for PET-2 negative patients. For 154 patients in which treatment was correctly given according to PET-2 review, the 2-year FFS was 91%: 62% for PET-2 positive and 95% for PET-2 negative patients. CONCLUSIONS: this strategy, with BEACOPP intensification only in PET-2 positive patients, showed better results than ABVD-treated historic controls, sparing BEACOPP toxicity to the majority of patients.     

Diagnostic accuracy of FDG PET/CT for clinical evaluation at the end of treatment of HL and NHL: a comparison of the Deauville Criteria (DC) and the International Harmonization Project Criteria (IHPC)

Purpose

To evaluate the accuracy and prognostic value of FDG PET/CT for response assessment after treatment in patients with Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) when using the Deauville Criteria (DC) and the International Harmonization Project Criteria (IHPC).

Methods

This retrospective study included 101 patients (35 HL, 66 NHL) who underwent early restaging FDG PET/CT after treatment. Scans were evaluated using the IHPC and DC. Two thresholds of positivity for the DC were used: a score of at least 3 (DC3, i.e. scores 3?–?5) and a score of at least 4 (DC4, i.e. a score of 4 or 5). Accuracy was assessed using conventional diagnostic procedures, multidisciplinary team case notes, further PET/CT scans and/or follow-up. Progression-free survival and overall survival were computed using the Kaplan-Meier method. The Cox proportional hazards model was used to identify predictors of outcome.

Results

Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of FDG PET/CT for early restaging were, respectively, 92 %, 87 %, 74 %, 92 % and 86 % using DC4, 97 %, 76 %, 64 %, 98 % and 84 % using DC3, and 97 %, 67 %, 57 %, 98 % and 76 % using the IHPC. FDG PET/CT positivity was associated with a worse cumulative survival rate over a 2-year period when using DC4 in comparison with the IHPC (20 % vs. 49 %; p?<?0.05) and DC3 (47 %; p?<?0.05). Cox regression analysis showed different risks of progression in patients positive on FDG PET/CT using the IHPC, DC3 and DC4 (hazard ratios 1.57, 0.7 and 3.2, respectively).

Conclusion

FDG PET/CT using DC4 showed higher diagnostic accuracy for HL and NHL than FDG PET/CT using either the IHPC or DC3, indicating its value in predicting clinical outcome after treatment.