Semi-supervised learning towards automated segmentation of PET images with limited annotations: application to lymphoma patients

Manual segmentation poses a time-consuming challenge for disease quantification, therapy evaluation, treatment planning, and outcome prediction. Convolutional neural networks (CNNs) hold promise in accurately identifying tumor locations and boundaries in PET scans. However, a major hurdle is the extensive amount of supervised and annotated data necessary for training. To overcome this limitation, this study explores semi-supervised approaches utilizing unlabeled data, specifically focusing on PET images of diffuse large B-cell lymphoma (DLBCL) and primary mediastinal large B-cell lymphoma (PMBCL) obtained from two centers. We considered 2-[18F]FDG PET images of 292 patients PMBCL (n = 104) and DLBCL (n = 188) (n = 232 for training and validation, and n = 60 for external testing). We harnessed classical wisdom embedded in traditional segmentation methods, such as the fuzzy clustering loss function (FCM), to tailor the training strategy for a 3D U-Net model, incorporating both supervised and unsupervised learning approaches. Various supervision levels were explored, including fully supervised methods with labeled FCM and unified focal/Dice loss, unsupervised methods with robust FCM (RFCM) and Mumford-Shah (MS) loss, and semi-supervised methods combining FCM with supervised Dice loss (MS + Dice) or labeled FCM (RFCM + FCM). The unified loss function yielded higher Dice scores (0.73 ± 0.11; 95% CI 0.67-0.8) than Dice loss (p value < 0.01). Among the semi-supervised approaches, RFCM + αFCM (α = 0.3) showed the best performance, with Dice score of 0.68 ± 0.10 (95% CI 0.45-0.77), outperforming MS + αDice for any supervision level (any α) (p < 0.01). Another semi-supervised approach with MS + αDice (α = 0.2) achieved Dice score of 0.59 ± 0.09 (95% CI 0.44-0.76) surpassing other supervision levels (p < 0.01). Given the time-consuming nature of manual delineations and the inconsistencies they may introduce, semi-supervised approaches hold promise for automating medical imaging segmentation workflows.

TMTV-Net: fully automated total metabolic tumor volume segmentation in lymphoma PET/CT images - a multi-center generalizability analysis

PURPOSE

Total metabolic tumor volume (TMTV) segmentation has significant value enabling quantitative imaging biomarkers for lymphoma management. In this work, we tackle the challenging task of automated tumor delineation in lymphoma from PET/CT scans using a cascaded approach.

METHODS

Our study included 1418 2-[18F]FDG PET/CT scans from four different centers. The dataset was divided into 900 scans for development/validation/testing phases and 518 for multi-center external testing. The former consisted of 450 lymphoma, lung cancer, and melanoma scans, along with 450 negative scans, while the latter consisted of lymphoma patients from different centers with diffuse large B cell, primary mediastinal large B cell, and classic Hodgkin lymphoma cases. Our approach involves resampling PET/CT images into different voxel sizes in the first step, followed by training multi-resolution 3D U-Nets on each resampled dataset using a fivefold cross-validation scheme. The models trained on different data splits were ensemble. After applying soft voting to the predicted masks, in the second step, we input the probability-averaged predictions, along with the input imaging data, into another 3D U-Net. Models were trained with semi-supervised loss. We additionally considered the effectiveness of using test time augmentation (TTA) to improve the segmentation performance after training. In addition to quantitative analysis including Dice score (DSC) and TMTV comparisons, the qualitative evaluation was also conducted by nuclear medicine physicians.

RESULTS

Our cascaded soft-voting guided approach resulted in performance with an average DSC of 0.68 ± 0.12 for the internal test data from developmental dataset, and an average DSC of 0.66 ± 0.18 on the multi-site external data (n = 518), significantly outperforming (p < 0.001) state-of-the-art (SOTA) approaches including nnU-Net and SWIN UNETR. While TTA yielded enhanced performance gains for some of the comparator methods, its impact on our cascaded approach was found to be negligible (DSC: 0.66 ± 0.16). Our approach reliably quantified TMTV, with a correlation of 0.89 with the ground truth (p < 0.001). Furthermore, in terms of visual assessment, concordance between quantitative evaluations and clinician feedback was observed in the majority of cases. The average relative error (ARE) and the absolute error (AE) in TMTV prediction on external multi-centric dataset were ARE = 0.43 ± 0.54 and AE = 157.32 ± 378.12 (mL) for all the external test data (n = 518), and ARE = 0.30 ± 0.22 and AE = 82.05 ± 99.78 (mL) when the 10% outliers (n = 53) were excluded.

CONCLUSION

TMTV-Net demonstrates strong performance and generalizability in TMTV segmentation across multi-site external datasets, encompassing various lymphoma subtypes. A negligible reduction of 2% in overall performance during testing on external data highlights robust model generalizability across different centers and cancer types, likely attributable to its training with resampled inputs. Our model is publicly available, allowing easy multi-site evaluation and generalizability analysis on datasets from different institutions.

Dosimetric Analysis of a Phase I Study of PSMA-Targeting Radiopharmaceutical Therapy With [177Lu]Ludotadipep in Patients With Metastatic Castration-Resistant Prostate Cancer

OBJECTIVE

177Lutetium [Lu] Ludotadipep is a novel prostate-specific membrane antigen targeting therapeutic agent with an albumin motif added to increase uptake in the tumors. We assessed the biodistribution and dosimetry of [177Lu]Ludotadipep in patients with metastatic castration-resistant prostate cancer (mCRPC).

MATERIALS AND METHODS

Data from 25 patients (median age, 73 years; range, 60-90) with mCRPC from a phase I study with activity escalation design of single administration of [177Lu]Ludotadipep (1.85, 2.78, 3.70, 4.63, and 5.55 GBq) were assessed. Activity in the salivary glands, lungs, liver, kidneys, and spleen was estimated from whole-body scan and abdominal SPECT/CT images acquired at 2, 24, 48, 72, and 168 h after administration of [177Lu]Ludotadipep. Red marrow activity was calculated from blood samples obtained at 3, 10, 30, 60, and 180 min, and at 24, 48, and 72 h after administration. Organ- and tumor-based absorbed dose calculations were performed using IDAC-Dose 2.1.

RESULTS

Absorbed dose coefficient (mean ± standard deviation) of normal organs was 1.17 ± 0.81 Gy/GBq for salivary glands, 0.05 ± 0.02 Gy/GBq for lungs, 0.14 ± 0.06 Gy/GBq for liver, 0.77 ± 0.28 Gy/GBq for kidneys, 0.12 ± 0.06 Gy/GBq for spleen, and 0.07 ± 0.02 Gy/GBq for red marrow. The absorbed dose coefficient of the tumors was 10.43 ± 7.77 Gy/GBq.

CONCLUSION

[177Lu]Ludotadipep is expected to be safe at the dose of 3.7 GBq times 6 cycles planned for a phase II clinical trial with kidneys and bone marrow being the critical organs, and shows a high tumor absorbed dose.

Long-term Clinical Outcomes of Optimizing Combination Therapy for Primary Pulmonary Mucosa-associated Lymphoid Tissue Lymphoma: A Retrospective Study

INTRODUCTION

Pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma progresses with advancing disease stage. However, no standard treatment approach has been established. This single-center retrospective study evaluated clinical and radiological characteristics, treatment modalities, and long-term prognosis of pulmonary MALT lymphoma.

METHODS

The study included 42 patients diagnosed with pulmonary MALT lymphoma between October 2004 and July 2019. Primary therapeutic modalities were determined using modified Ann Arbor staging. Therapeutic response was evaluated via computed tomography and laboratory analyses every 6 months for 5 years. Radiological findings were categorized based on the Lugano classification as complete response (CR), partial response, stable disease (SD), or progressive disease.

RESULTS

Initial treatment included observation (n=2), surgical resection (n=6), or systemic chemotherapy (n=34). Patients treated surgically had localized disease and achieved initial and long-term CR. Of the 34 patients who underwent chemotherapy, 30 achieved CR, 2 achieved SD, and 2 died. Overall and progression-free survival (PFS) rates were 93.9% and 54.3%, respectively. Multivariate analysis indicated that PFS was lower in patients with modified Ann Arbor stage III-IV lymphoma and those who did not achieve CR.

CONCLUSIONS

Optimized treatment based on anatomical location, pulmonary function, and disease stage can improve long-term survival in patients with pulmonary MALT lymphoma.

Prognostic Value of FDG PET/CT in Patients with Nodal Peripheral T-Cell Lymphoma

This study evaluated the prognostic significance of FDG PET/CT in patients with nodal peripheral T-cell lymphoma (PTCL). We retrospectively reviewed patients with histologically confirmed nodal PTCL who underwent FDG PET/CT at baseline, after three cycles of first-line chemotherapy (interim), and at the end of therapy. Response was assessed visually using the Deauville 5-point scale (D5PS); scores of 1, 2, and 3 were considered PET-negative, and scores of 4 and 5 were considered PET-positive. The associations between FDG PET/CT findings and survival were assessed using Cox regression analysis. A total of 79 patients (44 males and 35 females; median age 56 years) were included in this study. In response assessment, 17 (22%) had an interim PET-positive result and 10 (13%) had an end-of-therapy PET-positive result. During a median follow-up of 50 months, 37 patients (47%) presented with disease progression and 30 patients (38%) died. The estimated 5-year progression-free survival (PFS) and overall survival (OS) were 57% and 64%, respectively. An interim PET-positive result was the only significant indicator of PFS. Higher International Prognostic Index and end-of-therapy PET-positive result were significant independent prognostic factors of OS. Interim and end-of-therapy FDG PET/CT responses based on D5PS are meaningful in predicting the outcomes of patients with nodal PTCL.

Irreversible electroporation for prostate cancer using PSMA PET-CT

Background

To demonstrate the clinical usefulness of prostate-specific membrane antigen (PSMA) positron emission tomography (PET) computerized tomography (CT) for irreversible electroporation (IRE) in prostate cancer patients.

Methods

From January to May 2021, 17 men were diagnosed with localized prostate cancer through preoperative mpMRI and [¹⁸F] florastamin PSMA PET-CT imaging, followed by transperineal MRI-ultrasound fusion-guided biopsy. The patients underwent IRE focal therapy at the target lesions under general anesthesia. To evaluate the treatment outcome, serum prostate-specific antigen (PSA) levels were followed up in the 1st, 3rd, 6th, 9th, 12th months, and mpMRI was taken in the 1st and 12th months, followed by MR fusion biopsy in the 12th month post-IRE.

Results

The mean age of the patients was 66.1 ± 9.3 with a median PSA of 7.5 ng/ml. After the treatment, PSA nadir was 4.06 ± 3.4, and 11 (64.7%) achieved decline of PSA more than 50% from the baseline. Rate of negative biopsy for prostate cancer is 88% (15/17) at 12 months MR fusion biopsy after the IRE treatment. Among the relapsed cases, 1 (6.9%) patient recurred at margin of treated area, and 1 (6.9%) patient was from outfield recurrence. When excluding initial four patients, none of the patients had cancer recur.

Conclusions

When treating with IRE focal therapy, PSMA-PET CT is a potentially valuable diagnostic approach for localizing prostate cancer; it supports the detection of lesions with conventional mpMRI, enabling to perform the procedure more completely.

Diagnosis, treatment, and prognosis of primary intraocular lymphoma: Single-center real-world clinical experience

BACKGROUND

The diagnosis and management of primary intraocular lymphoma (PIOL) remain challenging. This study identified factors indicative of PIOL, described treatment outcomes, and determined modalities to prevent relapse.

METHODS

We included 21 PIOL-diagnosed patients, seven via cytology, 12 via genetic evaluation, and two via interleukin (IL) level measurements, who underwent vitrectomy and received local intravitreal methotrexate (IV-MTX) injection. Clinical outcomes, including treatment response and relapse, were compared between patients receiving IV-MTX alone (n = 13) or IV-MTX with systemic high-dose methotrexate (HD-MTX) as prophylaxis (n = 8).

RESULTS

Twelve ophthalmologic and eight central nervous system (CNS) relapse cases within a median of 20.3 and 11.6 months were shown, regardless of the treatment modalities, with a median progression-free survival of 21.3 (95% confidence interval, 9.5-36.7) months. There was no difference in demographic characteristics between the two groups, except with the poorer performance status in patients in the HD-MTX prophylaxis group. Furthermore, patients demonstrated rapid elevations in the vitreous fluid IL-10/IL-6 cytokine ratio before ophthalmologic and CNS relapse. Therefore, diagnosis should be based on clinical signs and assisted by vitrectomy, cytologic, molecular, and cytokine studies.

CONCLUSION

For PIOL, aggressive systemic treatment equivalent to that of primary CNS lymphoma (PCNSL) is recommended because solely HD-MTX did not prevent or delay CNS relapse. To prevent PIOL relapse in the CNS efficiently, prospective trials with large numbers of patients and advanced therapeutic regimens are necessary. Furthermore, regular clinical follow-up is crucial, and the IL-10/IL-6 ratio can help evaluate relapse promptly.

Trans-Aortic Flow Turbulence and Aortic Valve Inflammation: A Pilot Study Using Blood Speckle Imaging and 18F-Sodium Fluoride Positron Emission Tomography/Computed Tomography in Patients With Moderate Aortic Stenosis

BACKGROUND

¹⁸F-sodium fluoride positron emission tomography/computed tomography (¹⁸F-NaF PET/CT) has been proven to be useful in identification of microcalcifications, which are stimulated by inflammation. Blood speckle imaging (BSI) is a new imaging technology used for tracking the flow of blood cells using transesophageal echocardiography (TEE). We evaluated the relationship between turbulent flow identified by BSI and inflammatory activity of the aortic valve (AV) as indicated by the ¹⁸F-NaF uptake index in moderate aortic stenosis (AS) patients.

METHODS

This study enrolled 18 moderate AS patients diagnosed within the past 6 months. BSI within the aortic root was acquired using long-axis view TEE. The duration of laminar flow and the turbulent flow area ratio were calculated by BSI to demonstrate the degree of turbulence. The maximum and mean standardized uptake values (SUVmax, SUVmean) and the total microcalcification burden (TMB) as measured by ¹⁸F-NaF PET/CT were used to demonstrate the degree of inflammatory activity in the AV region.

RESULTS

The mean SUVmean, SUVmax, and TMB were 1.90 ± 0.79, 2.60 ± 0.98, and 4.20 ± 2.18 mL, respectively. The mean laminar flow period and the turbulent area ratio were 116.1 ± 61.5 msec and 0.48 ± 0.32. The correlation between SUVmax and turbulent flow area ratio showed the most positive and statistically significant correlation, with a Pearson's correlation coefficient (R²) of 0.658 and a p-value of 0.014.

CONCLUSIONS

The high degree of trans-aortic turbulence measured by BSI was correlated with severe AV inflammation.

A Single Dose of Novel PSMA-Targeting Radiopharmaceutical Agent [177Lu]Ludotadipep for Patients with Metastatic Castration-Resistant Prostate Cancer: Phase I Clinical Trial

[¹⁷⁷Lu]Ludotadipep, which enables targeted delivery of beta-particle radiation to prostate tumor cells, had been suggested as a promising therapeutic option for mCRPC. From November 2020 to March 2022, a total of 30 patients were enrolled for single dose of [¹⁷⁷Lu]Ludotadipep RPT, 6 subjects in each of the 5 different activity groups of 1.9 GBq, 2.8 GBq, 3.7 GBq, 4.6 GBq, and 5.6 GBq. [¹⁷⁷Lu]Ludotadipep was administered via venous injection, and patients were hospitalized for three days to monitor for any adverse effects. Serum PSA levels were followed up at weeks 1, 2, 3, 4, 6, 8, and 12, and PSMA PET/CT with [¹⁸F]Florastamin was obtained at baseline and again at weeks 4 and 8. The subjects required positive PSMA PET/CT prior to [¹⁷⁷Lu]Ludotadipep administration. Among the 29 subjects who received [¹⁷⁷Lu]Ludotadipep, 36 treatment emergent adverse events (TEAEs) occurred in 17 subjects (58.6%) and 4 adverse drug reactions (ADRs) in 3 subjects (10.3%). Of the total 24 subjects who had full 12-week follow-up data, 16 (66.7%) showed decrease in PSA of any magnitude, and 9 (37.5%) showed a decrease in PSA by 50% or greater. A total of 5 of the 24 patients (20.8%) showed disease progression (PSA increase of 25% or higher from the baseline) at the 12th week following single dose of [¹⁷⁷Lu]Ludotadipep. These data thus far suggest that [¹⁷⁷Lu]Ludotadipep could be a promising RPT agent with low toxicity in mCRPC patients who have not been responsive to conventional treatments.

Long-Term Clinical Outcomes in Treatment-Naïve Patients With Orbital Adnexal Mucosa-Associated Lymphoid Tissue Lymphoma: A Single-Center Study

Ocular adnexal mucosa-associated lymphoid tissue (MALT) lymphoma (OAML) is the most common type of ocular lymphoma with a higher prevalence in Asia than in Western countries. OAML represents 1%–2% of all non-Hodgkin’s lymphoma, 5%–15% of extranodal lymphomas, and approximately 55% of orbital malignancies. “Watch and wait” after biopsy or surgical resection, radiation therapy, and systemic treatment, including antibiotics administration and chemotherapy with various combinations of regimens can be considered for OAML treatment. Radiotherapy is adapted for limited-stage disease with excellent clinical outcomes of 85–100% complete remission and relatively superior local control efficacy and treatment duration. In contrast, chemotherapy has rarely been tested as frontline therapy. Nonetheless, several studies have reported a favorable response and long duration of progression-free survival using chemotherapy adaptations. When the disease involves both eyes or spreads beyond the conjunctiva, the risk of recurrence increases and limited-stage OAML has a recurrence rate of approximately 25% following radiotherapy only. Therefore, although recent consensus in the literature is that patients with limited-stage OAML recommended treating with radiation, physicians may choose the treatment modality not only by its efficiency but also by its adverse events profile and patients’ well-being. Herein, we present a large single-center study on OAML that included 292 patients who were followed up for up to 237 months. We collected and analyzed real-world data focusing on treatment outcomes and the role of radiotherapy as frontline therapy, and aimed to compare outcomes and complication profiles of chemotherapy, especially in limited-stage OAML, to identify an optimal treatment strategy.

Comparison of early F-18 Florbetaben PET/CT to Tc-99m ECD SPECT using voxel, regional, and network analysis

This study aimed to validate early-phase F-18 Florbetaben positron emission tomography (eFBB PET) as a brain perfusion test and determine the optimal reference region. A total of 27 patients with early Parkinson's disease with Tc-99m ethyl cysteinate dimer single photon emission tomography (ECD SPECT) and FBB PET were included. Six reference regions, including whole brain (GN), pons, central white matter (CWM), whole cerebellum (WC), WC with brain stem (WC + B), and cerebellar grey matter (CG), were applied to obtain SUVR using cortex volume-of-interest (VOI). Reference regions of WC (r 0.886), WC + B (r 0.897), and CG (r 0.904) had highest correlation values of cortex-VOI SUVR between both perfusion images (all p < 0.001). Early-phase FBB PET had a significant linear correlation of CG-normalized SUVR of the cortex, basal ganglia, thalamus, and midbrain with ECD SPECT in voxel-wise analysis (FDR adjusted-p < 0.05). Early-phase FBB PET extracts more ICNS than ECD SPECT, as 9 ICNS and 4 ICNs, respectively. Both eFBB PET and ECD SPECT well discriminated PD from DLB (Area-under-curve of receiver-operating-characteristics, 0.911 for eFBB PET, 0.922 for ECD SPECT). Our findings suggest that eFBB PET is a reliable perfusion test based on a high correlation with ECD SPECT using cerebellum-based normalization methods.

One Versus Up-to-5 Lesion Measurements for Response Assessment by PERCIST in Patients with Lung Cancer

Purpose

The optimal number of lesions to measure for response assessment from fluorine-18 fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) is not validated for lung cancer. We compared 1 lesion and up-to-5 lesion measurements for response assessment in lung cancer per PET Response Criteria in Solid Tumors (PERCIST).

Methods

Patients with lung cancer with pre- and post-treatment PET/CT images were included. The standard uptake value corrected for lean body mass (SUL_peak) of up-to-5 hottest target lesions was measured at each time point. The percent changes of SUL_peak of the single hottest lesion and the sum of up-to-5 hottest lesions were computed. Pearson correlation coefficient evaluated the strength of association between the percent changes of SUL_peak values from the 1 lesion and up-to-5 lesion analyses. Response categories were complete metabolic response (CMR) with no perceptible lesion; partial metabolic response (PMR), stable metabolic disease (SMD), or progressive metabolic disease (PMD) using the threshold of 30% and 0.8 unit change in SUL_peak; and unequivocal new lesion meant PMD. The concordance for response categorization was assessed by kappa statistics.

Results

A total of 40 patients (25 non-small cell lung cancer; 15 small cell lung cancer) were analyzed, all with ¹⁸F-FDG-avid lung cancer. Average of 3 target lesions were measured for up-to-5 lesion analysis. Pearson's r was 0.74 (P < 0.001) and increased to 0.96 (P < 0.001) when two outliers were excluded. Response categorization with 1 lesion and up-to-5 lesion analyses was concordant in 37 patients (92.5%, weighted kappa = 0.89).

Conclusion

Analyzing 1 lesion and up-to-5 lesions for response assessment by PERCIST showed high concordance in patients with lung cancer.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13139-021-00697-4.

Quantitation of cancer treatment response by 2-[18F]FDG PET/CT: multi-center assessment of measurement variability using AUTO-PERCIST™

Background

The aim of this study was to assess the reader variability in quantitatively assessing pre- and post-treatment 2-deoxy-2-[¹⁸F]fluoro-d-glucose positron emission tomography/computed tomography ([¹⁸F]FDG PET/CT) scans in a defined set of images of cancer patients using the same semi-automated analytical software (Auto-PERCIST™), which identifies tumor peak standard uptake value corrected for lean body mass (SUL_peak) to determine [¹⁸F]FDG PET quantitative parameters.

Methods

Paired pre- and post-treatment [¹⁸F]FDG PET/CT images from 30 oncologic patients and Auto-PERCIST™ semi-automated software were distributed to 13 readers across US and international sites. One reader was aware of the relevant medical history of the patients (read_reference), whereas the 12 other readers were blinded to history but had access to the correlative images. Auto-PERCIST™ was set up to first automatically identify the liver and compute the threshold for tumor measurability (1.5 × liver mean) + (2 × liver standard deviation [SD]) and then detect all sites with SUL_peak greater than the threshold. Next, the readers selected sites they believed to represent tumor lesions. The main performance metric assessed was the percent change in the SUL_peak (%ΔSUL_peak) of the hottest tumor identified on the baseline and follow-up images.

Results

The intra-class correlation coefficient (ICC) for the %ΔSUL_peak of the hottest tumor was 0.87 (95%CI: [0.78, 0.92]) when all reads were included (n = 297). Including only the measurements that selected the same target tumor as the read_reference (n = 224), the ICC for %ΔSUL_peak was 1.00 (95%CI: [1.00, 1.00]). The Krippendorff alpha coefficient for response (complete or partial metabolic response, versus stable or progressive metabolic disease on PET Response Criteria in Solid Tumors 1.0) was 0.91 for all reads (n = 380) and 1.00 including for reads with the same target tumor selection (n = 270).

Conclusion

Quantitative tumor [¹⁸F]FDG SUL_peak changes measured across multiple global sites and readers utilizing Auto-PERCIST™ show very high correlation. Harmonization of methods to single software, Auto-PERCIST™, resulted in virtually identical extraction of quantitative tumor response data from [¹⁸F]FDG PET images when the readers select the same target tumor.

Prognostic value of tumor metabolic imaging phenotype by FDG PET radiomics in HNSCC

OBJECTIVE

Tumor metabolic phenotype can be assessed with integrated image pattern analysis of ¹⁸F-fluoro-deoxy-glucose (FDG) Positron Emission Tomography/Computed Tomography (PET/CT), called radiomics. This study was performed to assess the prognostic value of radiomics PET parameters in head and neck squamous cell carcinoma (HNSCC) patients.

METHODS

¹⁸F-fluoro-deoxy-glucose (FDG) PET/CT data of 215 patients from HNSCC collection free database in The Cancer Imaging Archive (TCIA), and 122 patients in Seoul St. Mary's Hospital with baseline FDG PET/CT for locally advanced HNSCC were reviewed. Data from TCIA database were used as a training cohort, and data from Seoul St. Mary's Hospital as a validation cohort. With the training cohort, primary tumors were segmented by Nestles' adaptive thresholding method. Segmental tumors in PET images were preprocessed using relative resampling of 64 bins. Forty-two PET parameters, including conventional parameters and texture parameters, were measured. Binary groups of homogeneous imaging phenotypes, clustered by K-means method, were compared for overall survival (OS) and disease-free survival (DFS) by log-rank test. Selected individual radiomics parameters were tested along with clinical factors, including age and sex, by Cox-regression test for OS and DFS, and the significant parameters were tested with multivariate analysis. Significant parameters on multivariate analysis were again tested with multivariate analysis in the validation cohort.

RESULTS

A total of 119 patients, 70 from training, and 49 from validation cohort, were included in the study. The median follow-up period was 62 and 52 months for the training and the validation cohort, respectively. In the training cohort. binary groups with different metabolic radiomics phenotypes showed significant difference in OS (p = 0.036), and borderline difference in DFS (p = 0.086). Gray-Level Non-Uniformity for zone (GLNU_GLZLM) was the most significant prognostic factor for both OS (hazard ratio [HR] 3.1, 95% confidence interval [CI] 1.4-7.3, p = 0.008) and DFS (HR 4.5, CI 1.3-16, p = 0.020). Multivariate analysis revealed GLNU_GLZLM as an independent prognostic factor for OS (HR 3.7, 95% CI 1.1-7.5, p = 0.032). GLNU_GLZLM remained as an independent prognostic factor in the validation cohort (HR 14.8. 95% CI 3.3-66, p < 0.001).

CONCLUSIONS

Baseline FDG PET radiomics contain risk information for survival prognosis in HNSCC patients. The metabolic heterogeneity parameter, GLNU_GLZLM, may assist clinicians in patient risk assessment as a feasible prognostic factor.

FDG PET/CT Findings of Castleman Disease Assessed by Histologic Subtypes and Compared with Laboratory Findings

Castleman disease (CD) is a relatively rare lymphoproliferative disorder and the pathophysiology of the subtypes are incompletely understood. Fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) demonstrates the metabolic activity of inflammatory and tumorous conditions. The FDG uptake intensity and sites of involved lesions on FDG PET/CT were assessed by histologic subtypes, and compared to the patient's hemoglobin, platelet, albumin, and high-sensitivity C-reactive protein (hs-CRP) levels. In total, 60 PET/CT images of 44 consecutive CD patients were included: 4 (9%) unicentric and 40 (91%) multicentric; 21 (48%) hyaline vascular subtype, 16 (36%) plasma cell, and 7 (16%) mixed or unclassified. The maximum standardized uptake value (SUVmax) and tumor-to-liver (T/L) ratio of involved lymph nodes (LNs) were 5.3 ± 2.4 (range, 1.6-11.5) and 2.8 ± 1.6 (range, 1.1-9.6), respectively, with no significant difference between the histologic subtypes. Higher number of involved LN stations and presence of extra-nodal involvement on FDG PET/CT were associated with thrombocytopenia, hypoalbuminemia, and elevated hs-CRP levels (p values < 0.05). FDG-avidity was not different by histologic subtypes and did not correlate with laboratory findings. However, the extent of nodal and extra-nodal involvement as noted on FDG PET/CT was significantly associated with abnormal laboratory findings in patients with CD.

Early Interim Chemotherapy Response Evaluation by F-18 FDG PET/CT in Diffuse Large B Cell Lymphoma

Fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) after one cycle of standard chemotherapy in patients with diffuse large B cell lymphoma (DLBCL) was assessed. Prospectively enrolled 51 patients had four PET/CT studies using the same protocol and system: at baseline and after one, three, and six cycles of chemotherapy (PET0, PET1, PET3, PET6). The PET1 and PET6 Deauville five-point score (D5PS) agreed in 60.8%, while PET3 and PET6 D5PS agreed in 90.2%. The absolute and percent changes of peak standard uptake value corrected for lean body mass (SULpeak) compared to baseline were significantly different between PET1 and PET3 (p = 0.001, p < 0.001) and PET1 and PET6 (p = 0.002, p = 0.001), but not between PET3 and PET6 (p = 0.276, p = 0.181). The absolute SULpeak from PET1 predicted treatment failure with accuracy of 78.4% (area under the curve 0.73, p = 0.023). D5PS, SULpeak, and metabolic tumor volume (MTV) were not statistically different between responders versus non-responders, or the one year disease-free versus relapse groups. D5PS and PERCIST responses showed 100% agreement at end-of-therapy. In conclusion, the responses after three and six cycles of therapy showed high degree of agreement. D5PS or MTV after one cycle of chemotherapy could not predict response or one-year disease-free status, but the SULpeak from PET1 was associated with response to first line therapy in DLBCL. Deauville and PERCIST criteria show high concordance.

Spontaneous Remission and Concomitant Progression in a Patient with DLBCL

Diffuse large B-cell lymphoma (DLBCL) is the most common type of lymphoma. Although DLBCL can be cured in more than half of all patients, up to 50% of patients become refractory to initial treatment or relapse after complete remission. We present a case of complete spontaneous remission of some tumors and concomitant newly developed tumors observed in a patient with relapsed DLBCL. Spontaneous remission of lymphoma without treatment is a rare phenomenon and can occur at baseline as well as in relapsed DLBCL. However, most patients who initially experience spontaneous remission later develop relapse. Thus, careful follow-up is required, and fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) allows monitoring of multiple lesions.

Role of F-18 FDG PET/CT in non-conjunctival origin ocular adnexal mucosa-associated lymphoid tissue (MALT) lymphomas

Background

Despite the widespread use of F-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) in the diagnosis and response assessment of patients with lymphoma, few studies have assessed its value in ocular adnexal lymphomas. The purpose of this study was to evaluate the role of FDG PET/CT in staging of non-conjunctival origin ocular adnexal mucosa-associated lymphoid tissue (MALT) lymphomas (OAML). In addition, the diagnostic sensitivity of FDG PET/CT was compared with magnetic resonance imaging (MRI). FDG PET/CT of 123 consecutive patients with pathologically proven OAML between January 2009 and February 2016 were retrospectively reviewed. The patients with MALT lymphoma originating from conjunctiva were excluded. A total 50 patients with non-conjunctival origin OAML were assessed. Maximum standardized uptake value (SUVmax) and additional PET parameters were measured for all lesions. Sensitivity for primary tumor detection was compared with MRI.

Results

Ten patients had bilateral OAML and total 60 OAML lesions were analyzed. MRI was missing in one patient. The tumor locations were as follows: eyelid, 9; lacrimal gland, 18; orbit, 33. Fifty lesions (83.3%) were FDG-avid tumors with mean ± SD SUVmax 4.8 ± 2.4 (range 2.0~11.1). The mean SUVmax according to tumor location were as follows: eyelid, 3.7 ± 1.1 (2.8~5.3); lacrimal gland, 3.6 ± 1.4 (2.1~6.4); orbit, 5.7 ± 2.6 (2.0~11.1). Mean SUVmax among the 3 locations were statistically different (P = 0.010). The sensitivity was calculated as 83.1% (49/59) for FDG PET/CT and 89.8% (53/59) for MRI, which were statistically comparable (P = 0.219 by McNemar’s test). Seven of 50 patients (14%) were upstaged by detection of extraocular lesions by FDG PET/CT (1 kidney and lung, 1 tonsil, 4 cervical LNs, 1 sacral foramen).

Conclusion

83.3% of the non-conjunctival origin OAML were FDG-avid tumors, with FDG PET/CT showing comparable sensitivity to that of MRI. FDG PET/CT detected unsuspected extraocular lymphoma involvement in 14% of the patients. FDG PET/CT performed for staging of non-conjunctival origin OAML may thus guide therapeutic management.

Anti-inflammatory effect of statin is continuously working throughout use: a prospective three time point 18F-FDG PET/CT imaging study

No data exist whether statins have robust anti-inflammatory effects of atherosclerotic plaques primarily during the early treatment period or continuously throughout use. This prospective three time point ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) study of the carotid artery assessed anti-inflammatory effects of statin during the early treatment period (initiation to 3 months) and late treatment period (3 months to 1 year) and their correlation with lipid and inflammatory profile changes during a year of therapy. Nine statin-naïve stable angina patients with inflammatory carotid plaques received 20 mg/day atorvastatin after undergoing initial ¹⁸F-FDG PET/CT scanning of carotid arteries and ascending thoracic aorta, and then completed serial ¹⁸F-FDG PET/CT imaging at 3 and 12 months whose data were analyzed. The primary outcome was the inter-scan percent change in target-to-background ratio (ΔTBR) within the index vessel. At 3 months of atorvastatin treatment, mean serum low-density lipoprotein cholesterol (LDL-C) level decreased by 36.4% to < 70 mg/dL (p = 0.001) and mean serum high-density lipoprotein cholesterol level increased to > 40 mg/dL (p = 0.041), with both maintained with no further reduction up to 1 year (p = 0.516 and 0.715, respectively) while mean serum high sensitivity C-reactive protein level only numerically decreased (p = 0.093). The index vessel ΔTBR showed continuous plaque inflammation reduction over 1 year, by 4.4% (p = 0.015) from the initiation to 3rd months and 6.2% (p = 0.009) from 3rd months to 1 year, respectively, without correlation with lipid profile changes. The ΔTBR of the bilateral carotid arteries and ascending aorta also continuously decreased from 3 months to 1 year. Three time point ¹⁸F-FDG PET/CT imaging demonstrates that statin's anti-inflammatory effect continues throughout its use up to 1 year, even though yielding stable below-target plasma LDL-C levels at 3 months.

Effect of Pioglitazone in Combination with Moderate Dose Statin on Atherosclerotic Inflammation: Randomized Controlled Clinical Trial Using Serial FDG-PET/CT

BACKGROUND AND OBJECTIVES

Non-statin therapy plus lower intensity statin might be an alternative in patients with coronary artery disease (CAD). A recent data suggested an anti-inflammatory therapy can reduce recurrent cardiovascular events and pioglitazone is also an intriguing inflammatory-modulating agent. However, limited data exist on whether pioglitazone on top of statins further attenuates plaque inflammation.

METHODS

Statin-naïve patients with stable CAD and carotid plaques of ≥3 mm were randomly prescribed moderate dose atorvastatin (20 mg/day), or moderate dose atorvastatin plus pioglitazone (30 mg/day) for 3 months. The primary endpoint was the change in the arterial inflammation of the carotid artery measured by ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) during 3 months.

RESULTS

Of the 41 randomized patients, 33 underwent an evaluation by fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT; 17 atorvastatin plus pioglitazone and 16 atorvastatin patients). The addition of pioglitazone significantly improved the insulin sensitivity and increased the high-density lipoprotein cholesterol after 3 months. Although a reduction in the (FDG) uptake by pioglitazone on top of atorvastatin in carotid arteries with plaque showed marginally statistical significance in the entire patient group (atorvastatin plus pioglitazone; -0.10±0.07 and atorvastatin -0.06±0.04, p=0.058), pioglitazone showed a further reduction of the fluorodeoxyglucose (FDG) uptake among patients who had a baseline FDG uptake above the median (atorvastatin plus pioglitazone; -0.14±0.04 and atorvastatin -0.03±0.03, p<0.001).

CONCLUSIONS

Pioglitazone demonstrated marginally significant anti-inflammatory effects in addition to moderate dose atorvastatin. This may have been due to the lack of power of the study. However, pioglitazone may have an anti-inflammatory effect in those patients with high plaque inflammation (Trial registry at ClinicalTrials.gov, NCT01341730).

Cardiac and Pericardial 18F-FDG Uptake on Oncologic PET/CT: Comparison with Echocardiographic Findings

BACKGROUND

Interpretation of cardiac uptake on 18-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) is often confounded by intense physiological FDG uptake and numerous benign conditions. The aim of the study was to describe the echocardiographic features in concordance with cardiac and pericardial ¹⁸F-FDG uptake on whole-body oncology PET/CT.

METHODS

We enrolled 43 consecutive patients (34 solid tumors, 8 lymphomas and 1 leukemia) who were newly diagnosed with non-cardiac malignancy showing incidental cardiac or pericardial ¹⁸F-FDG uptake on PET/CT and underwent transthoracic Doppler echocardiography (TTE) within 1 month of PET/CT. The maximum standardized uptake (SUV_max) of all lesions was measured.

RESULTS

Fifty-six ¹⁸F-FDG uptake lesions (32 pericardium, 7 myocardium, 9 cardiac chambers and 8 great vessels) were found, and pericardial effusion was the most common echocardiographic finding (22/43, 51.2%) among study population. Pericardial FDG uptake was shown as pericardial effusion (68.8%), intrapericardial echogenic materials (31.3%), pericardial thickening (28.1%), hyperechogenicity of myopericardium (18.8%), and restricted sliding movement or constrictive pericarditis (15.6%) on TTE. Lesions with regional wall motion abnormality (p = 0.004) or constrictive pericarditis (p = 0.021) had significantly higher mean SUV_max than those without. Myocardial FDG uptake demonstrated pericardial effusion (57.1%), regional wall motion abnormality (57.1%), and increased myocardial wall thickness (42.9%). All cardiac chamber FDG uptakes showed intracardiac mass on TTE.

CONCLUSIONS

Cardiac or pericardial ¹⁸F-FDG uptake on oncology PET/CT shows characteristic echocardiographic features according to which heart sites are involved.

Correlation Between Infection Status of Epstein-Barr Virus and 18F-Fluorodeoxyglucose Uptake in Patients with Advanced Gastric Cancer

BACKGROUND

Epstein-Barr virus-associated gastric cancer (EBVaGC) is one of the four molecular subtypes of gastric cancer, as defined by the classification recently proposed by The Cancer Genome Atlas. We evaluated the correlation between EBV positivity and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake by positron emission tomography/computed tomography (PET/CT) in patients with gastric cancer.

MATERIALS AND METHODS

We retrospectively enrolled patients with gastric cancer who underwent pretreatment ¹⁸F-FDG PET/CT and subsequent surgical resection, and then were diagnosed with advanced gastric cancer (pathologic stage ≥T2 with any N stage). Maximum standardized uptake values (SUV_max) of gastric cancer were measured by pretreatment ¹⁸F-FDG PET/CT. EBV sequences were detected by in situ hybridization (ISH) techniques. We analyzed the correlation between EBV positivity, clinicopathologic features and metabolic activity of the primary tumor.

RESULTS

A total of 205 patients were included and 15 (7.3%) patients were identified as having EBV-positive gastric cancer. Age, gender, tumor location, and histological type showed no significant differences between EBV-positive and negative groups. EBV-positive cancer is significantly more frequent in the higher-metabolic-tumor group than in the lower one (p=0.032). The mean SUV_max of gastric cancers showed significant differences between EBV-positive and negative groups (9.9±4.2 vs. 7.0±4.8, p=0.026).

CONCLUSION

The infection status of EBV was significantly related to the ¹⁸F-FDG uptake of primary tumors in patients with advanced gastric cancer.

PERCIST in Perspective

Positron Emission tomography Response Criteria In Solid Tumors (PERCIST) version 1.0 was introduced in 2009 for objective assessment of tumor metabolic response using 18F-FDG PET/CT. Practical PERCIST: A Simplified Guide to PET Response Criteria in Solid Tumors 1.0 was published in 2016 to review and clarify some of the issues with the PERCIST. In this article, we reflect on the benefits and challenges of implementing PERCIST, and speculate on topics that could be discussed in PERCIST 1.1 in the future.

The value of pre- and post-neoadjuvant chemotherapy F-18 FDG PET/CT scans in breast cancer: comparison with MRI

Background Accurate assessment of neoadjuvant chemotherapy (NAC) response with positron emission tomography/computed tomography (PET/CT) or magnetic resonance imaging (MRI) may provide appropriate operation guidelines for individual breast cancer patients. Purpose To compare the values of PET/CT and MRI for response evaluation following NAC in breast cancer patients. Material and Methods Thirty-three consecutive patients who underwent NAC were included. PET/CT and MRI were performed before and one to four weeks after NAC. With response evaluation of PET/CT and MRI, patients with complete/partial responses on imaging studies were considered to be responders, and those showing stable/progressive disease non-responders. Peak standardized uptake value corrected for lean body mass (SULpeak) and metabolic tumor volume (MTV) were measured from PET/CT, and unidimensional diameter (1D) and tumor volume (TV) from MRI. Reduction rates for each parameter were calculated (Δ%SULpeak, Δ%MTV, Δ%1D, and Δ%TV). The pathological response for NAC as reference was evaluated after surgical resection of the remaining tumor in the breast. Results We identified 17 pathological responders and 16 non-responders. PET/CT had lower specificity and accuracy, but higher sensitivity than MRI, although no significant difference was found between PET/CT and MRI. Following NAC, there were significant differences between pathological responders and non-responders in SULpeak ( P < 0.001), MTV ( P < 0.001), 1D ( P = 0.0003), TV ( P = 0.038), Δ%SULpeak ( P = 0.001), Δ%MTV ( P < 0.001), Δ%1D ( P < 0.001), and Δ%TV ( P = 0.001). Conclusion PET/CT showed lower specificity and accuracy than MRI in evaluating responses to NAC, but both PET/CT and MRI parameters may have predictive value in distinguishing therapeutic responders and non-responders following NAC.

Coronary-to-pulmonary artery fistula in adults: Evaluation with thallium-201 myocardial perfusion SPECT

Objectives

With the increasing use of multi-detector CT, the number of detected cases with coronary-to-pulmonary artery fistula (CPAF) has increased. Several previous studies reported severe cases of angina, but no appropriate tests to evaluate myocardial perfusion for patients with CPAF have been established. We evaluated the hemodynamic characteristics of CPAF using thallium-201 (Tl-201) single photon emission computed tomography (SPECT).

Materials and methods

Tl-201 SPECT was performed in 17 patients with CPAF, but without evidence of coronary artery disease on coronary computed tomography angiography (CCTA) (age, 58.5±13.3 years; 8 men). Quantitative analysis of scintigraphic data was performed. Additionally, perfusion abnormalities were compared with CCTA findings. Medical records were obtained to define clinical data, diagnostic findings, symptoms, management, follow-up data, and major adverse cardiac events (MACE).

Results

Six patients (35.2%) showed perfusion abnormalities on SPECT studies and could be classified as follows: 3 patients, no reversible ischemia (3/17, 17.6%); 1 patient, mild ischemia (1/17, 5.8%); and 2 patients, moderate ischemia (2/17, 11.7%). During the follow-up, ten patients (58.8%) improved under medical management and 5 patients (29.4%) underwent surgical ligation for CPAF with symptomatic improvement in 4 patients. Seven patients performed follow-up myocardial perfusion SPECT, and symptomatic improvement correlated well with scintigraphic perfusion improvement in 6 patients No MACE was observed.

Clinical significance

Tl-201 myocardial perfusion SPECT might be useful for determining the hemodynamic status and for risk stratification in patients with CPAF.

Evaluation of Slug expression is useful for predicting lymph node metastasis and survival in patients with gastric cancer

BACKGROUND

Slug is a transcription factor that activates the epithelial-mesenchymal transition (EMT) process in cancer progression. The aim of our study was to evaluate the clinical significance of Slug expression in gastric cancer.

METHODS

The expression of Slug in gastric cancer tissues of 456 patients who underwent gastrectomy was evaluated by immunohistochemistry using tissue microarrays. Slug expression level was defined by the composite score determined by multiplying the tumor staining scores for intensity and extent. The associations of Slug expression with clinicopathological characteristics and overall and recurrence-free survival were analyzed.

RESULTS

Patients were divided into three groups according to Slug composite score (≤4, 6, and 9). Low, mid, and high expression of Slug was observed in 104 (22.7%), 130 (28.3%), and 225 (49.0%) of cases, respectively. Overall survival and recurrence-free survival progressively increased from high to low Slug expression. In terms of lymph node metastasis, the rate of positive lymph node metastasis was 38/104 (36.5%), 79/130 (60.8%), and 178/225 (79.1%) in low, mid, and high Slug expression groups, respectively, displaying a tendency to increase with higher Slug expression. In a multivariate analysis adjusting for patient age, tumor size, tumor depth, and histology, high Slug expression was associated with a high rate of positive lymph node metastasis compared with low Slug expression (odds ratio 3.42; 95% confidence interval, 1.74-6.69). In a subgroup analysis of T1 cancer, patients with negative Slug expression (defined as <5% positive tumor cells or no/weak staining) showed no lymph node metastasis (0/13), whereas those with positive Slug expression showed 15.9% (17/107) lymph node metastasis, with a negative predictive value of 100%.

CONCLUSIONS

High expression of Slug in gastric cancer tissue was associated with lymph node metastasis and poor survival. Evaluation of Slug would be useful for discriminating patients at high risk of lymph node metastasis in early gastric cancer.

Prognostic Value of Pre- and Post-Treatment FDG PET/CT Parameters in Small Cell Lung Cancer Patients

Purpose

To evaluate the prognostic value of PET parameters obtained from pre- and post-treatment FDG PET/CT examinations in patients with SCLC.

Methods

Fifty-nine patients with initially diagnosed SCLC from 2009 to 2014 were included and had chemotherapy and/or concurrent chemoradiotherapy. FDG PET/CT examinations were performed before (PET1) and after (PET2) treatment to evaluate treatment response. A region of interest was placed over the primary lesion and metastatic lymph nodes within the thoracic cavity. PET parameters including change from PET1 to PET2 (Δ in %) were acquired: SUVmax, SUVpeak, MTV2.5, TLG, ΔSUVmax, ΔSUVpeak, ΔMTV and ΔTLG. Patient characteristics including staging, age, sex, LDH and response evaluation by RECIST were surveyed. Statistical analysis was done using Kaplan-Meier method and Cox regression analysis with respect to OS and PFS.

Results

The median follow-up was 9.6 months (2.5-80.5 months). 27 patients were LD and 32 were ED. Forty-six patients (78.0%) had died, and median OS was 8.6 months; 51 patients (86%) showed disease progression, and median PFS was 2.5 months. On univariate analysis, patients with ED, high interval change (ΔSUVmax and ΔSUVpeak) and low PET2 parameters showed longer OS and PFS. Multivariate analyses demonstrated that ΔSUVpeak (HR 2.6, P = 0.002) was an independent prognostic factors for OS, and MTV2.5 of PET2 (HR 2.8, P = 0.001), disease stage (HR 2.7, P = 0.003) and RECIST (HR 2.0, P = 0.023) were independent prognostic factors for PFS.

Conclusions

Metabolic and volumetric PET parameters obtained from pre- and post-treatment FDG PET/CT examinations in patients with SCLC have significant prognostic information.

18F-FDG PET/CT and histology for diagnosing recurrent/remnant tumors in head and neck cancer patients treated with radiotherapy

OBJECTIVE

The aim of this study was to assess the diagnostic performance of fluorine-18-fluoro-2-deoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) for locoregional recurrent/residual tumor in patients with head and neck cancer (HNC) who underwent previous radiotherapy (RT).

SUBJECTS AND METHODS

¹⁸F-FDG PET/CT images from patients with HNC who previously underwent RT were retrospectively reviewed. Only cases with histological confirmation within 4 weeks of PET/CT imaging were included. Standardized uptake values were obtained for lesions and PET/CT findings were compared with histological results.

RESULTS

Of 181 cases, 114 (63%) were histologically confirmed as malignant and 67 (37%) as benign. The sensitivity, specificity, and accuracy of PET/CT were 93%, 64%, and 82%, respectively. Inflammation was the most common cause of false positives and small tumor volume and low ¹⁸F-FDG avidity were the causes of false negatives. PET/CT had 100% sensitivity and 56% specificity for detecting recurrent or residual disease within 12 weeks after RT and 93% sensitivity and 64% specificity, more than 12 weeks after RT. The frequency of false positives in PET/CT images within 12 weeks of RT was similar to the results obtained 12 weeks after RT (15% vs. 14%). False positives were more frequent in PET/CT cases after two-dimensional or three-dimensional conformal RT than in those after intensity-modulated RT, although not statistically significant (15% vs. 9%, p>0.05).

CONCLUSION

¹⁸F-FDG PET/CT might aid the diagnosis of locoregional residual/recurrent tumors in patients with HNC previously treated with RT. Inflammation was the main cause of false positives regardless of the interval between RT and PET/CT, even several years after RT. Therefore, histological verification of positive PET/CT findings should be conducted during follow-up of HNC patients treated with RT.

Clinicopathological characteristics including BRAF V600E mutation status and PET/CT findings in papillary thyroid carcinoma

OBJECTIVE

We assessed the associations between FDG uptake in primary papillary thyroid carcinomas (PTCs) and clinicopathological features, including the BRAF V600E mutation, using quantitative and qualitative analyses of preoperative PET/CT data.

DESIGN AND PATIENTS

This was a retrospective review of 106 patients with PTC who underwent PET/CT scans between February 2009 and January 2011 before undergoing total thyroidectomy. Data collected from surgical specimens were compared with FDG uptake in the primary tumour using quantitative and qualitative analyses of preoperative PET/CT data. Clinicopathological data included the primary tumour size, subtype, capsular invasion, extrathyroid extension, multifocality, BRAF V600E mutation status, lymph node metastasis and distant metastasis.

RESULTS

The SUVmax of the primary tumour was significantly higher in patients with a primary tumour >1 cm, extrathyroid extension or the BRAF V600E mutation than in patients without these features (P<.001, .049 and <.001). Univariate analyses showed that primary tumour size, extrathyroid extension and BRAF V600E mutation status were associated with the SUVmax of the PTC. Multivariate analysis indicated that primary tumour size and the BRAF V600E mutation were associated with the SUVmax of the PTC. In a visual assessment, the primary tumour size was larger in FDG-avid than in non-FDG-avid PTCs (P<.001). There was no significant difference in the presence of multifocality, thyroid capsular invasion, extrathyroid extension, BRAF V600E mutation, lymph node metastasis or distant metastasis between FDG-avid and non-FDG-avid PTCs.

CONCLUSIONS

Primary tumour size and the BRAF V600E mutation are significant factors associated with the SUVmax on preoperative PET/CT in patients with PTC.

Quantitation of Cancer Treatment Response by 18F-FDG PET/CT: Multicenter Assessment of Measurement Variability

The aim of this study was to assess the interobserver variability of quantitative ¹⁸F-FDG PET/CT parameters used in assessments of treatment response across multiple sites and readers. Methods: Paired pre- and posttreatment ¹⁸F-FDG PET/CT images of 30 oncologic patients were distributed to 22 readers across 15 U.S. and international sites. One reader was aware of the full medical history (read_reference) of the patients, whereas the 21 other readers were unaware. The readers selected the single hottest tumor from each study, and made SUV measurements from this target lesion and the liver. Descriptive statistics, percentage changes in the measurements, and their agreements were obtained. Results: The intraclass correlation coefficient for the percentage change in SUV_max (%ΔSUV_max) of the hottest tumor was 0.894 (95% confidence interval [CI], 0.813-0.941), and the individual equivalence coefficient was 1.931 (95% CI, 0.568-6.449) when all reads were included (n = 638). When only the measurements that selected the same target tumor as the read_reference (n = 486) were included, the intraclass correlation coefficient for the %ΔSUV_max was 0.944 (95% CI, 0.841-0.989), and the individual equivalence coefficient was -0.688 (95% CI, -1.810 to -0.092). The absolute change in SUV_mean of liver corrected for lean body mass showed upper and lower limits of agreement (average bias ± 2 SDs) of 0.13 and -0.13 g/mL. Conclusion: The quantitative tumor SUV changes measured across multiple sites and readers show a high correlation. Selection of the same tumor target among readers further increased the degree of correlation.

Analysis of treatment outcomes for primary tonsillar lymphoma

Purpose

Although each Waldeyer’s ring sub-site is considered an independent prognostic factor, few studies have assessed the prognosis and treatment of tonsillar lymphoma. Treatment outcomes were analyzed in patients with primary tonsillar lymphoma who were treated with chemotherapy and radiotherapy (RT).

Materials and Methods

Nineteen patients with diffuse large B-cell lymphoma were evaluated, with a median follow-up of 53 months. Age, sex, and histology, amongst other factors, were reviewed. Progression-free survival (PFS) and overall survival (OS) rates were analyzed.

Results

Most patients had Ann Arbor stage I-II (94.7%), IPI score of 0 (89.5%), and complete remission after chemotherapy (89.5%). The 5-year PFS and OS rates were 74.6% and 80%, respectively. In univariate analysis, the rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) regimen resulted in a better PFS than the cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) regimen (88.9% vs. 50.0%; p = 0.053). RT dose was related to the survival outcome (p = 0.010 for PFS, p = 0.044 for OS). Patients were classified into the CHOP + RT (>40 Gy) group and R-CHOP + RT (≤40 Gy) group. The 5-year PFS rates were 50% in the CHOP + RT group, and 100 % in the R-CHOP + RT group (p = 0.018). The 5-year OS rates were 66.7% and 100%, respectively (p = 0.087).

Conclusion

Primary tonsillar lymphoma patients typically have favorable outcomes. Chemotherapy (R-CHOP) combined with relatively lower dose consolidative RT may be safe and effective for primary tonsillar lymphoma.

FDG PET/CT response in diffuse large B-cell lymphoma: Reader variability and association with clinical outcome

F-18-fluoro-2-deoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is essential for monitoring response to treatment in patients with diffuse large B-cell lymphoma (DLBCL) and qualitative interpretation is commonly applied in clinical practice. We aimed to evaluate the interobserver agreements of qualitative PET/CT response in patients with DLBCL and the predictive value of PET/CT results for clinical outcome.PET/CT images were obtained for patients with DLBCL 3 times: at baseline, after 3 cycles of first-line chemotherapy (interim), and after completion of chemotherapy. Two nuclear medicine physicians (with 3 and 8 years of experience with PET/CT) retrospectively assessed response to chemotherapy blinded to the clinical outcome using International Harmonization Project (IHP) criteria and Deauville 5-point score. The associations between PET/CT results and progression-free survival (PFS) and overall survival (OS) were assessed using Cox regression analysis.A total of 112 PET/CT images were included from 59 patients with DLBCL (36 male, 23 female; mean age 53 ± 14 years). Using the IHP criteria, interobserver agreement was substantial (Cohen κ = 0.76) with absolute agreement consistency of 89%. Using the Deauville score, interobserver agreement was moderate (Cohen weighted κ = 0.54) and absolute consistency was 62%. The most common cause of disagreements was discordant interpretation of residual tumor uptake. With median follow-up period of 60 months, estimated 5-year PFS and OS were 81% and 92%, respectively. Neither interim nor posttreatment PET/CT results by both readers were significantly associated with PFS. Interim PET/CT result by the more experienced reader using Deauville score was a significant factor for OS (P = 0.019).Moderate-to-substantial interobserver agreement was observed for response assessments according to qualitative PET/CT criteria, and interim PET/CT result could predict OS in patients with DLBCL. Further studies are necessary to further standardize the PET/CT-based response criteria for more consistent interpretation.

Practical PERCIST: A Simplified Guide to PET Response Criteria in Solid Tumors 1.0

Positron Emission Tomography (PET) Response Criteria in Solid Tumors (PERCIST 1.0) describes in detail methods for controlling the quality of fluorine 18 fluorodeoxyglucose PET imaging conditions to ensure the comparability of PET images from different time points to allow quantitative expression of the changes in PET measurements and assessment of overall treatment response in PET studies. The steps for actual application of PERCIST are summarized. Several issues from PERCIST 1.0 that appear to require clarification, such as measurement of size and definition of unequivocal progression, also are addressed. (©) RSNA, 2016.

Is the Glut expression related to FDG uptake in PET/CT of non-small cell lung cancer patients?

Though 18F-FDG PET/CT scans are widely used in non-small cell lung cancer (NSCLC), the mechanism of FDG uptake by lung cancer cells has not yet been fully elucidated. This study evaluated the relationship between FDG uptake and the expression of glucose transporters in NSCLC. Sixty-four NSCLC patients who underwent both preoperative 18F-FDG PET/CT scanning and thoracotomy were included. The maximum standardized uptake value (SUVmax) of the primary lung cancer was compared to the immunohistochemistry results for Glut expression and tumor size. In all the NSCLC cases, degree of FDG uptake significantly correlated with both Glut-1 and Glut-3 expression. When stratified by the histology, squamous cell carcinomas showed higher mean SUVmax, Glut-1 expression intensity, and percentage of area positive for Glut-1 expression than adenocarcinomas. Glut-1 and Glut-3 expressions correlated with SUVmax in adenocarcinomas, but there was no significant correlation in squamous cell carcinomas. No significant correlation was observed between tumor size and FDG uptake or Glut expression. These results show that Glut expression was significantly correlated with SUVmax in NSCLC, especially in adenocarcinomas, and that neither FDG uptake nor the expression of Glut was associated with tumor size.

Response to Early Treatment Evaluated with 18F-FDG PET and PERCIST 1.0 Predicts Survival in Patients with Ewing Sarcoma Family of Tumors Treated with a Monoclonal Antibody to the Insulinlike Growth Factor 1 Receptor

The aim of this study was to assess the prognostic and predictive value of early quantitative (18)F-FDG PET to monitor therapy with an antibody to the insulinlike growth factor 1 receptor (IGF-1R antibody) in patients with Ewing sarcoma family of tumors (ESFT).

METHODS

(18)F-FDG PET images at baseline and approximately 9 d after initiation of IGF-1R antibody therapy in 115 patients with refractory or relapsed ESFT were prospectively obtained as part of the Sarcoma Alliance for Research through Collaboration trial. Responses were centrally evaluated by PERCIST 1.0 in 93 patients. The 9-d PET responses were correlated to overall survival (OS), progression-free survival (PFS), and clinical benefit after 6 wk of therapy based on clinical observation and CT response by World Health Organization anatomic criteria.

RESULTS

The median OS was 8.1 mo (95% confidence interval, 6.4-10.0 mo). When PERCIST was used, patients with progressive metabolic disease showed shorter OS (median, 4.7 mo) than patients without progression (median, 10.0 mo; P = 0.001). Progressive metabolic disease on day-9 PET was associated with a significantly higher risk of death (hazard ratio, 2.8; 95% confidence interval, 1.5-5.5). Changes in (18)F-FDG uptake after 9 d of therapy had an area under the curve of receiver-operating characteristic of 0.71 to predict 1-y OS. The area under the curve was 0.63 to predict progression at 3 mo and 0.79 to predict clinical benefit after 6 wk of therapy.

CONCLUSION

Treatment response by quantitative (18)F-FDG PET assessed by PERCIST 1.0 as early as 9 d into IGF-1R antibody therapy in patients with ESFT can predict the OS, PFS, and clinical response to therapy.

The Prognostic Value of (18)F-FDG PET/CT for Early Recurrence in Operable Breast Cancer: Comparison with TNM Stage

PURPOSE

We evaluated whether the maximum standardized uptake values (SUVmax) of primary tumor from the initial staging by (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) of patients with breast cancer could identify patients at risk for early recurrence within 2 years, particularly in comparison to the American Joint Committee on Cancer (AJCC) stage.

METHODS

We reviewed the staging (18)F-FDG PET/CT images of patients with primary breast cancer and their medical records. The SUVmax of the primary tumor was measured. The presence or absence of FDG uptake in the axillary lymph node (ALN) was also assessed. The patient's pathologic primary tumor stage (pT), pathologic regional lymph node stage (pN), stage grouping, age, estrogen receptor (ER) and progesterone receptor (PR) status, and neoadjuvant chemotherapy history were evaluated with the FDG uptake parameters for recurrence within 2 years following the end of first-line therapy.

RESULTS

Recurrence within 2 years was present in 9.1 % (n = 40) out of the 441 patients assessed. The FDG uptake in ALN, pT, pN, stage grouping and neoadjuvant chemotherapy history were prognostic for early recurrence, while primary tumor SUVmax, age, and ER or PR status were not significant on logistic regression. On multivariate analysis, only the stage grouping (odds ratio 2.79; 95 % CI 1.73, 4.48; p < 0.0001) and neoadjuvant chemotherapy history (odds ratio 2.70; 95 % CI 1.22, 5.98; p = 0.0141) could identify patients at increased risk for recurrence within 2 years.

CONCLUSIONS

Primary tumor FDG uptake measured by SUVmax, and visual assessment of FDG uptake in the ALN in the initial staging PET/CT of patients with breast cancer may not have additional prognostic value compared with the AJCC stage grouping for early recurrence.

Bone recurrence after curative resection of gastric cancer

BACKGROUND

Standard follow up for bone recurrence has not yet been established for gastric cancer after surgical resection. The aim of this study was to investigate the incidence of and related risk factors for bone recurrence after surgical resection of gastric cancer.

METHODS

A cohort of 3035 gastric cancer patients after curative resection was reviewed. We analyzed the patients who had bone scintigraphy before the surgery as well as during the follow-up period. The incidence of and the risk factors for bone recurrence after surgical resection of gastric cancer were investigated.

RESULTS

In a total of 1683 patients analyzed, bone recurrence was detected in 30 patients (1.8%). The incidence of bone recurrence was significantly higher in advanced gastric cancers than in early lesions (3.5 vs. 0.4%, p < 0.01). The most common recurrence site was the spine, followed by pelvic bone and rib. Most patients had multiple bone metastases. The median time for recurrence was 28 months (range 4-111) from the surgery. In univariate analysis, the recurrence rate was higher in the tumors with large size, undifferentiated pathology, location in the body, and advanced stage. In multivariate analysis, lymph node metastasis (N2/N3 vs. N0/N0I) was the most predictable risk factor for bone recurrence [hazard ratio [HR] 1.44 (95% confidence interval [CI] 1.217-1.694)] and depth of invasion (T2-4 vs. T1) was also independently associated with bone recurrence.

CONCLUSIONS

The incidence of bone recurrence was low after curative surgery in patients with gastric cancer. Intensive follow up with bone scintigraphy seems to be unnecessary in these patients.

Clinical significance of incidental colonic 18F-FDG uptake on PET/CT images in patients with gastric adenocarcinoma

BACKGROUND AND OBJECTIVES

We assessed the ability of positron emission tomography-computed tomography (PET/CT) to detect synchronous colonic pathology and determined the significance of 18F-fluorodeoxyglucose (18F-FDG) activity in the colon of gastric cancer patients.

METHODS

A total of 239 gastric cancer patients who underwent PET/CT and colonoscopy preoperatively were included. FDG uptake patterns on PET/CT were classified as (1) group A, focal; (2) group B, diffuse; and (3) group C, no uptake. The PET/CT findings were compared with the results of concurrent colonoscopy.

RESULTS

In group A, a total of 123 polyps of >0 mm were observed. Of these, nine polyps were colonic adenocarcinomas and six were high-grade dysplasia. The incidence of colonic adenocarcinomas was significantly higher in group A than in the other two groups (p = 0.037). There was a significant correlation between SUVmax values and incidence of colonic polyps of >10 mm (r = 0.471, p = 0.04). The distribution pattern of SUVmax in polyps with adenoma (>10 mm) was less homogenous than in polyps (>10 mm) with adenocarcinoma.

CONCLUSIONS

The focal colonic FDG uptake in PET/CT requires colonoscopic confirmation. The suspicion of colonic malignancy increased in the presence of polyps >10 mm that showed a positive correlation with the SUVmax.

Value of Surveillance (18)F-FDG PET/CT in Colorectal Cancer: Comparison with Conventional Imaging Studies

PURPOSE

To assess the value of PET/CT for detecting local or distant recurrence in patients who undergo surgery for colorectal cancer (CRC) and to compare the accuracy of PET/CT to that of conventional imaging studies (CIS).

METHODS

Tumor surveillance PET/CT scans done between March 2005 and December 2009 of disease-free patients after surgery with or without adjuvant chemotherapy for CRC were retrospectively studied. CIS (serial enhanced CT from lung base to pelvis and plain chest radiograph) were performed within 1 month of PET/CT. We excluded patients with distant metastasis on initial staging, a known recurrent tumor, and a lack of follow-up imaging. The final diagnosis was based on at least 6 months of follow-up with colonoscopy, biopsy, and serial imaging studies in combination with carcinoembryonic antigen levels.

RESULTS

A total of 262 PET/CT scans of 245 patients were included. Local and distant recurrences were detected in 27 cases (10.3%). On case-based analysis, the overall sensitivity, specificity, and accuracy were 100, 97.0, and 97.3% for PET/CT and 85.1, 97.0, and 95.8% for CIS, respectively. On lesion-based analysis, PET/CT detected more lesions compared to CIS in local recurrence and lung metastasis. PET/CT and CIS detected the same number of lesions in abdominal lymph nodes, hepatic metastasis, and peritoneal carcinomatosis. PET/CT detected two more metachronous tumors than did CIS in the lung and thyroid gland.

CONCLUSION

PET/CT detected more recurrences in patients who underwent surgery for CRC than did CIS and had the additional advantage of evaluating the entire body during a single scan.

Role of [(18)F]-fluorodeoxy-D-glucose positron emission tomography and computed tomography in the early detection of persistent/recurrent thyroid carcinoma in intermediate-to-high risk patients following initial radioactive iodine ablation therapy

BACKGROUND

Positron emission tomography/computed tomography (PET/CT) scan has a role in the surveillance of patients with a history of thyroid carcinoma. Its efficacy after remnant ablation as far as detecting persistent or recurrent thyroid carcinoma before other surveillance methods is not known, however. In intermediate-to-high risk thyroid carcinoma patients we studied whether PET/CT scan, performed 6-12 months after the first remnant ablation, could provide more information than ultrasonography (US) and thyrotropin-stimulated serum thyroglobulin (Tg) determination with diagnostic whole-body scan (DxWBS).

METHODS

We studied 71 subjects with differentiated thyroid cancer (DTC) who were intermediate-to-high risk for persistent/recurrent disease and who had received PET/CT scan, US, and DxWBS simultaneously with stimulated Tg levels 6-12 months after remnant ablation. To evaluate the diagnostic efficacy of PET/CT scan, the sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were calculated.

RESULTS

Ten subjects (14%) had persistent/recurrent disease detected 6-12 months after remnant ablation. Persistence/recurrence was detected in nine (12.7%) of these patients by conventional methods, including US and DxWBS, along with stimulated Tg levels. The remaining case was detected solely by a PET/CT scan, which showed a mediastinal prevascular lesion; this was confirmed by a therapeutic WBS after additional radioiodine therapy. Among the six patients whose PET/CT scan showed positive results, five had persistent/recurrent disease. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of PET/CT scan for detecting persistent/recurrent thyroid carcinoma were 50%, 98.4%, 83.3%, 92.3%, and 91.5%, respectively.

CONCLUSION

In intermediate-to-high risk patients with DTC seen 6-12 months after their first remnant ablation, there is almost no complementary role for adding a PET/CT scan to conventional follow-up methods, an US and a DxWBS simultaneously with stimulated Tg levels.

Clinical significance of observation without repeated radioiodine therapy in differentiated thyroid carcinoma patients with positive surveillance whole-body scans and negative thyroglobulin

BACKGROUND/AIMS

Currently, there is no consensus on the necessity of repeated radioiodine therapy (RAI) in patients who show iodine uptake in the thyroid bed on a diagnostic whole-body scan (DxWBS) despite undetectable thyroglobulin (Tg) levels after remnant ablation. The present study investigated the clinical outcomes of scan-positive, Tg-negative patients (WBS+Tg-) who did or did not receive additional RAI.

METHODS

We retrospectively reviewed 389 differentiated thyroid carcinoma patients who underwent a total thyroidectomy and received high-dose RAI from January 2003 through December 2005. The patients were classified according to surveillance DxWBS findings and TSH-stimulated Tg levels 6 to 12 months after the initial RAI.

RESULTS

Forty-four of the 389 patients (11.3%) showed thyroid bed uptake on a DxWBS despite negative Tg levels (WBS+Tg-). There was no difference in clinical and pathological parameters between WBS+Tg- and WBS-Tg- patients, except for an increased frequency of thyroiditis in the WBS+Tg- group. Among the 44 WBS+Tg- patients, 27 subjects were treated with additional RAI; 25 subjects showed no uptake in subsequent DxWBS. Two patients were evaluated only by ultrasonography (US) and displayed no persistent/recurrent disease. The other 17 patients received no further RAI; Eight patients and two patients showed no uptake and persistent uptake, respectively, on subsequent DxWBS. Six patients presented negative subsequent US findings, and one was lost to follow-up. Over the course of 53.2 ± 10.1 months, recurrence/persistence was suspicious in two patients in the treatment group.

CONCLUSIONS

There were no remarkable differences in clinical outcomes between observation and treatment groups of WBS+Tg- patients. Observation without repeated RAI may be an alternative management option for WBS+Tg- patients.

Significance of incidental focal uptake in prostate on 18-fluoro-2-deoxyglucose positron emission tomography CT images

To evaluate the clinical significance of incidental focal prostate fluorodeoxyglucose (FDG) uptake, we reviewed 18-F-FDG positron emission tomography (PET)/CT scans from 2003 to 2007 and selected cases with focal FDG uptake in prostate. Cases of known prostate cancer were excluded. The maximum standardised uptake value (SUV(max)), site (central or peripheral) and pattern (discrete or ill-defined) of FDG uptake, calcification (present or absent) and prostate volume (<30 or ≥30 cc) were recorded. The PET/CT findings were correlated with serum prostate-specific antigen (PSA) levels, imaging studies, clinical follow-up and biopsy. Of a total of 5119 cases, 63 (1.2%) demonstrated focal FDG uptake in prostate. Eight cases were lost to follow-up. Among the 55 cases with follow-up, malignancy was confirmed by biopsy in 3 (5.4%). The three malignant cases had SUV(max) values of 3.3, 3.6 and 2.3, and all were noted in the peripheral portion of prostate; two of these cases had a discrete FDG uptake pattern, none had calcification corresponding to the FDG uptake area and one had a prostatic volume greater than 30 cc. The mean SUV(max) of 52 benign cases was 3.2 ± 1.7 and focal FDG uptake was noted in the peripheral portion in 34 (65%), 20 (38%) cases showed a discrete FDG uptake pattern, 35 (67%) were accompanied by calcification and 32 (62%) had a prostatic volume greater than 30 cc. The majority of cases demonstrating focal FDG uptake in prostate were benign and no PET/CT finding could reliably differentiate benign from malignant lesions; however, when discrete focal FDG uptake without coincidental calcification is seen, particularly in the peripheral zone of the prostate, further clinical evaluation is recommended.

The value of dual-time-point 18F-FDG PET/CT for identifying axillary lymph node metastasis in breast cancer patients

OBJECTIVE

The sensitivity of 18-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) for detecting axillary lymph node (ALN) metastases in breast cancer is reported to be low. Several studies have shown, however, that dual-time-point (18)F-FDG PET imaging provides improved accuracy in the diagnosis of certain primary tumours when compared with single-scan imaging. The purpose of this study was to assess whether the use of dual-time-point (18)F-FDG PET/CT scans could improve the diagnostic accuracy of ALN metastasis in breast cancer.

METHOD

The study included 171 breast cancer patients who underwent pre-operative (18)F-FDG PET/CT scans at 2 time-points, the first at 1 h after radiotracer injection and the second 3 h after injection. Where (18)F-FDG uptake was in the ALN perceptibly increased, the maximum standardised uptake values for both time-points (SUVmax1 and SUVmax2) and the retention index (RI) were calculated. Correlation between the PET/CT results and post-operative histological results was assessed.

RESULTS

The performance of 1 h and 3 h PET/CT scans was equal, with sensitivity 60.3% and specificity 84.7%, in detecting ALN metastasis. Out of 171 patients, 60 had ALNs with increased (18)F-FDG uptake on 1 h or 3 h images. There was no significant difference in RI between the metastatic ALN-positive group and the node-negative group. The area under the receiver operating characteristic (ROC) curve for SUVmax1 was 0.90 (p<0.001) and 0.87 for SUVmax2 (p<0.001).

CONCLUSION

Dual time-point imaging did not improve the overall performance of (18)F-FDG PET/CT in detecting ALN metastasis in breast cancer patients.

Hypoperfusion and ischemia in cerebral amyloid angiopathy documented by 99mTc-ECD brain perfusion SPECT

Cerebral amyloid angiopathy (CAA) is known to be an important cause of spontaneous cortical-subcortical intracranial hemorrhage in normotensive older persons. CAA can also manifest as leukoencephalopathy, brain atrophy, and ischemia secondary to hypoperfusion. Our goal was to verify cerebral hypoperfusion in patients with CAA using (99m)Tc-ethylcysteinate dimer ((99m)Tc-ECD) brain perfusion SPECT.

METHODS

A total of 11 patients (5 men and 6 women; age range, 58-78 y; mean age +/- SD, 70.0 +/- 7.0 y) with clinically and radiologically established probable CAA who underwent (99m)Tc-ECD SPECT were included. (99m)Tc-ECD SPECT scans were also obtained from 13 age-matched healthy control subjects (7 men and 6 women; age range, 60-79 y; mean age +/- SD, 66.7 +/- 6.4 y) for comparison. The relative regional cerebral blood flow values obtained for patients and controls were compared using software.

RESULTS

Compared with controls, patients with probable CAA showed hypoperfusion in the inferior parietal lobule of both parietal lobes (Brodmann area [BA] 40), middle temporal gyrus of the left temporal lobe (BA 39), postcentral gyrus of the right parietal lobe, superior temporal gyrus of the right temporal lobe (BA 22), superior temporal gyrus of the right frontal lobe (BA 10), inferior temporal gyrus of the left temporal lobe (BA 20), and both caudate bodies (P < 0.0001, t = 4.65).

CONCLUSION

Patients with probable CAA had significantly decreased cerebral perfusion and may be at risk for leukoencephalopathy, atrophy, and ischemia.