Initial experience with FDG-PET/CT in the evaluation of breast cancer

Purpose We retrospectively reviewed FDG-PET/CT images in patients with breast cancer to determine whether PET/CT improved the level of diagnostic confidence as compared with PET and to compare PET/CT and CT findings at the location of suspected malignancies.Methods The study included 75 patients with known breast cancer. The initial PET/CT study for each patient was retrospectively reviewed to determine whether improved diagnostic confidence (IDC) regarding lesion localization and characterization was observed with PET/CT as compared with PET alone. PET/CT and CT findings were compared regarding lesion characterization and staging in 69 of the 75 patients, and in the case of discordant findings, comparison with histological or informative follow-up results was also performed.Results Fifty of the 75 patients exhibited increased FDG uptake in a total of 95 regions. In the comparison of PET/CT and PET, PET/CT resulted in IDC in 30 (60%) of these 50 patients and in 52 (55%) of the 95 regions. In the comparison between PET/CT and CT in 69 patients, PET/CT demonstrated a significantly better accuracy than CT (P<0.05). PET/CT showed definitely positive findings in 60 regions with malignancies, among which CT exhibited positive findings in 43 (72%). PET/CT and CT accurately staged 59 (86%) and 53 (77%) of the 69 patients, respectively.Conclusions PET/CT added incremental diagnostic confidence to PET in more than 50% of patients and regions with increased FDG uptake. PET/CT accurately detected more regions with malignancies than did CT. This initial evaluation suggests that PET/CT is preferable to PET or CT in the diagnosis of breast cancer.     

PET/MRI of the breast

The future clinical use of the combination of positron emission tomography (PET) with 2-Fluoro[F-18]-2-Deoxy-d-Glucose (FDG)and MRI is still unclear. If a patient requires a PET and breast DCE-MRI for staging purposes, both scans can be done in the same visit. In the breast, DCE-MRI is better at lesion detection (sensitivity), margin evaluation, and has a higher specificity than CT. The potential for multiparametric qualitative and quantitative imaging is also an advantage of PET/MRI which provides opportunity to improve tumor characterization and may ultimately lead to outcome prediction. This review discusses technical and clinical aspects of this emerging technology in breast cancer patients.     

Integrated PET/CT in the preoperative staging of lung cancer: A prospective comparison of CT,PET and integrated PET/CT

Purpose

The purpose of this study was to evaluate the role of integrated PET/CT in the staging of lung cancer compared with CT alone or PET alone.

Materials and methods

Thirty-three patients underwent integrated PET/CT for the staging of lung cancer. The tumor, node and metastasis (TNM) stages were assessed with CT, PET and integrated PET–CT and compared with the surgical and pathological staging.

Results

CT correctly evaluated the (T) status in (64%) of the patients, PET in (59%) and PET/CT in (86%). CT correctly evaluated the (N) status in (73%) of the patients, PET in (76%), and PET/CT (88%) with accuracy, sensitivity, specificity, PPV and NPV were 73%, 78%, 71%, 50% and 94% for CT, 76%, 67%, 79%, 55% and 95% for PET and 88%, 89%, 88%, 73% and 100% for PET/CT respectively, and for (M) status were 91%, 86%, 92%, 75% and 96% for CT, 88%, 71%, 92%, 71% and 92% for PET and 97%, 100%, 96%, 88% and 100% for PET/CT respectively. Regarding the overall TNM staging CT correctly staged 24 patients. PET correctly staged 23 cases while PET/CT correctly staged 30 cases. A significant difference in the accuracy of overall tumor staging between PET/CT and CT (P = 0.0412) or PET (P = 0.0233).

Conclusion

The integrated PET/CT is superior to either CT or PET in the staging of lung cancer which has an important impact on selection of the appropriate treatment regimen.     

Regional PET/CT after water gastric inflation for evaluating loco-regional disease of gastric cancer

Objective

We aimed to improve diagnostic accuracy of ¹⁸F-fluoro-2-deoxyglucose (FDG) PET/CT for gastric cancer with water gastric inflation.

Materials and methods

44 gastric cancer patients (M:F = 30:14, age ± std = 62.1 ± 14.5y) were enrolled before surgery. Fifty minutes after injection of FDG (0.14 mCi/kg body weight), whole body PET/CT was performed first and then regional PET/CT over gastric area was obtained 80 min post FDG injection after water gastric inflation. Diagnostic accuracies for loco-regional lesions were compared between whole body and regional PET/CT.

Results

48 primary tumors (23 EGC and 25 AGC) and 348 LN stations (61 metastatic and 287 benign) in 44 patients were investigated. Primary tumor sensitivity of whole body PET/CT (50% = 24/48) was significantly improved by regional PET/CT (75% = 36/48, p < 0.005). Sensitivity of whole body PET/CT (24.6% = 15/61) for LN metastasis was also significantly improved by regional PET/CT (36.1% = 22/61, p < 0.01), whereas specificity of whole body PET/CT (99.3% = 285/287) was not compromised by regional PET/CT (98.3% = 282/287, p > 0.05). Higher primary tumor FDG uptake in regional PET/CT indicated shorter progress-free survival (p = 0.0003).

Conclusion

Diagnostic accuracy of whole body PET/CT for loco-regional disease of gastric cancer could be significantly improved by regional PET/CT after water gastric inflation and prognosis could be effectively predicted by primary tumor FDG uptake in regional PET/CT.     

Integrated contrast-enhanced diagnostic whole-body PET/CT as a first-line restaging modality in patients with suspected metastatic recurrence of breast cancer

Objective(s)

Only few information exist about the diagnostic accuracy of PET/CT for restaging patients with metastatic recurrence of breast carcinoma. Therefore, our study hypothesis was to perform diagnostic contrast enhanced CT (ce-CT) and FDG-PET in a one-step investigation, to prove sensitivity of each modality and to determine whether diagnostic PET/CT adds information over PET or contrast enhanced CT alone for restaging of patients with suspected recurrence of breast cancer.

Methods

Fifty-two patients with suspected recurrence of breast cancer were included in our study. All of them were free of metastasis after the first line therapy. Indications for restaging were: Elevated tumor markers n = 32, clinical deterioration n = 16 and/or suspicious findings on other imaging studies n = 48. Integrated PET/CT was performed using contrast-enhanced diagnostic CT for attenuation correction.

Results

PET was correct in 44/52 patients (85%), ce-CT in 38/52 patients (73%) and PET/CT in 50/52 patients (96%). Sensitivity and specificity of lesion detection of PET, CT and PET/CT were 84%, 66% and 93%, and 100%, 92%, and 100%, respectively.

Discussion

PET/CT can improve staging and alter therapeutic options in patients suspected to have breast cancer recurrence and distant metastatic disease, primarily by demonstrating local or distant nodal involvement occult at other imaging studies. The added value of FDG-PET/CT over other diagnostic modalities is mainly expressed by the fact that a noninvasive whole-body evaluation is possible in a single examination.     

X线和PET/CT在早期食管癌诊断中的应用

目的:探讨早期食管癌的细微X线征像。方法:回顾性分析16例经手术病理证实的早期食管癌X线表现和其中6例PET/CT征像。结果:16例患者中食管鳞状上皮重度不典型增生1例,鳞癌14例,原位癌1例。食管钡餐造影表现有:①结节样充盈缺损;②扁平样充盈缺损;③粟粒样充盈缺损;④粘膜线增粗。PET/CT检查显示6例患者病灶均显示FDG代谢增高。结论:早期食管癌的钡餐造影检查表现多样,PET/CT对病灶的检出敏感性高,多种检查方法相结合可以提高诊断准确性,同时更准确的进行术前评估。     

Higher breast cancer conspicuity on dbPET compared to WB-PET/CT

ObjectivesThe purpose of this study was to evaluate lesion detectability of a dedicated breast positron-emission tomography (dbPET) scanner for breast cancers with an updated reconstruction mode, comparing it to whole-body positron-emission tomography/computed tomography (WB-PET/CT).Materials and methodsA total of 179 histologically-proven breast cancer lesions in 150 females who underwent both WB-PET/CT and dbPET with ¹⁸F-fluorodeoxyglucose were retrospectively analyzed. The patient/breast/lesion-based sensitivities based on visual analysis were compared between dbPET and WB-PET/CT. For lesions visible on both PET images, SUVmax values of the tumors were measured, and tumor-to-background ratios (T/B ratios) of SUVmax were compared between the two scans. Subgroup analyses according to clinical tumor stage, histopathology and histological grade were also performed.ResultsPatient/breast/lesion-based sensitivities were 95%, 95%, and 92%, respectively, for dbPET, and 95%, 94%, and 88%, respectively, for WB-PET/CT. Mean ± standard deviation SUVmax values of FDG-avid tumors were 13.0 ± 9.7 on dbPET and 6.4 ± 4.8 on WB-PET. T/B ratios were also significantly higher in dbPET than in WB-PET/CT (8.1 ± 7.1 vs. 5.1 ± 4.5). In the subgroup analysis, no significant differences in sensitivities between dbPET and WB-PET/CT were found. However, T/B ratios of dbPET were significantly higher than those of WB-PET/CT in cT1c, cT2, cT3, invasive cancer, invasive carcinoma of no special type, mucinous carcinoma and Grades 1–3.ConclusionNo significant differences in sensitivities were identified between dbPET using an updated reconstruction mode and WB-PET/CT; however, T/B ratios of dbPET were significantly higher than those of WB-PET/CT, indicating higher tumor conspicuity on dbPET.     

PET/CT在乳腺癌中的应用

乳腺癌是女性最常见的恶性肿瘤,如能得到早期诊断并早期治疗可明显地改善患者的预后情况甚至可以完全治愈。近年来正电子发射断层显像(PET)以及18F-FDG的广泛应用极大地改善了肿瘤患者的诊断和分期问题,及时改变了相应的治疗方法,而单纯的PET显像由于解剖定位欠清,有时正常生理性摄取与异常病理性摄取可能会难以鉴别,PET/CT的出现弥补了上述缺点,使FDGPET/CT在乳腺癌的分期与再分期、疗效监测、术前评估、原发病灶的诊断以及治疗方案的制订中都体现出自身独特的优势。     

Comparison of whole-body PET/CT and PET/MRI in breast cancer patients: Lesion detection and quantitation of 18F-deoxyglucose uptake in lesions and in normal organ tissues

Purpose

To compare the performance of PET/MRI imaging using MR attenuation correction (MRAC) (DIXON-based 4-segment -map) in breast cancer patients with that of PET/CT using CT-based attenuation correction and to compare the quantification accuracy in lesions and in normal organ tissues.

Methods

A total of 36 patients underwent a whole-body PET/CT scan 1 h after injection and an average of 62 min later a second scan using a hybrid PET/MRI system. PET/MRI and PET/CT were compared visually by rating anatomic allocation and image contrast. Regional tracer uptake in lesions was quantified using volumes of interest, and maximal and mean standardized uptake values (SUVmax and SUVmean, respectively) were calculated. Metabolic tumor volume (MTV) of each lesion was computed on PET/MRI and PET/CT. Tracer uptake in normal organ tissue was assessed as SUVmax and SUVmean in liver, spleen, left ventricular myocardium, lung, and muscle.

Results

Overall 74 FDG positive lesions were visualized by both PET/CT and PET/MRI. No significant differences in anatomic allocation scores were found between PET/CT and PERT/MRI, while contrast score of lesions on PET/MRI was significantly higher. Both SUVmax and SUVmean of lesions were significantly higher on PET/MRI than on PET/CT, with strong correlations between PET/MRI and PET/CT data (ρ = 0.71–0.88). MTVs of all lesions were 4% lower on PET/MRI than on PET/CT, but no statistically significant difference was observed, and an excellent correlation between measurements of MTV with PET/MRI and PET/CT was found (ρ = 0.95–0.97; p < 0.0001). Both SUVmax and SUVmean were significantly lower by PET/MRI than by PET/CT for lung, liver and muscle, no significant difference was observed for spleen, while either SUVmax and SUVmean of myocardium were significantly higher by PET/MRI. High correlations were found between PET/MRI and PET/CT for both SUVmax and SUVmean of the left ventricular myocardium (ρ = 0.91; p < 0.0001), while moderate correlations were found for the other normal organ tissues (ρ = 0.36–0.61; p < 0.05).

Conclusions

PET/MRI showed equivalent performance in terms of qualitative lesion detection to PET/CT. Despite significant differences in tracer uptake quantification, due to either methodological and biological factors, PET/MRI and PET/CT measurements in lesions and normal organ tissues correlated well. This study demonstrates that integrated whole-body PET/MRI is feasible in a clinical setting with high quality and in a short examination time.     

Choline PET/CT for prostate cancer: Main clinical applications

Several studies investigated the potential roles of imaging modalities in prostate cancer patients for the evaluation of intra-prostatic disease, stage and restage. However no precise guidelines exist about the use of imaging modalities, in particular about the role of PET/CT hybrid imaging. Considering the results of the literature and our experience, we tried to summarize the main applications of choline positron emission tomography (PET) in prostate cancer patients. The use of choline PET/CT for initial diagnosis and staging is not recommended as a first-line method. Instead the main and important application of choline PET/CT is represented by the restaging of the disease in case of biochemical relapse for the detection of lymph node and distant recurrence. In particular choline PET/CT could play a crucial role as first diagnostic procedure in prostate cancer patients who show a fast growing Prostate Specific Antigen (PSA) kinetics.     

^18氟-脱氧葡萄糖PET/CT显像在原发性肝细胞癌中的应用研究

目的评价18氟-脱氧葡萄糖(18FDG)PET/CT在原发性肝细胞癌中的应用价值.材料和方法28例患者被分成3组.第一组为未经相关治疗的HCC组,共13例;第二组为肝脏良性病变组,共9例;第三组为HCC治疗后疗效观察组,共6例.18FDG PET/CT影像学表现结合手术病理及临床随访,计算18FDG PET/CT对HCC诊断的敏感性,并分析标准摄取值(SUV)的影响因素.结果第一组患者Ⅰ型表现7例,Ⅱ型表现5例,Ⅲ型表现1例;第二组患者Ⅰ型表现0例,Ⅱ型表现4例,Ⅲ型表现5例;18FDG PET/CT对HCC诊断的灵敏度为53.8%,其SUV值的大小和肿瘤的生物学行为有关.第三组患者Ⅰ型表现5例,Ⅱ型表现0例,Ⅲ型表现1例,其SUV值的大小与肿瘤残留有关.结论18FDG PET/CT显像在HCC生物学特性评估及HCC治疗后疗效监测方面有明显优势.     

The diagnostic value of PET/CT in recurrence and distant metastasis in breast cancer patients and impact on disease free survival

Aim of work

To detect the diagnostic value of PET/CT in breast cancer patients. We compared the performance of PET/CT with that of conventional imaging in detection of recurrence and distant metastasis and evaluated the impact PET/CT results have on disease free survival.

Materials and methods

We retrospectively studied 50 patients with breast cancer with clinical suspicion of recurrent or metastatic lesion and who underwent PET/CT and conventional imaging procedures. The imaging results were retrospectively compared with histopathology and clinical follow-up as a reference standard.

Results

PET/CT detected distant metastases with a sensitivity of 97% and a specificity of 93%. In contrast, the sensitivity and specificity of combined conventional imaging procedures were 75% and 73%, respectively, disease-free survival was significantly shorter in the 34 M1-PET/CT patients than in the 14 M0-PET/CT patients (log-rank P = 0.002) also PET/CT detected recurrence in 1 patient with equivocal mammographic findings.

Conclusion

In breast cancer, PET/CT is superior to conventional imaging procedures for detection of recurrence, distant metastases and PET/CT can be used to improve prediction of the clinical outcome of breast cancer patients.     

PET/CT对肿瘤放疗策略的影响

目的：探讨PET／CT对肿瘤放疗策略的影响。方法：对189例恶性肿瘤进行放疗前^18F-FDG全身PET／CT检查,应用标准摄取值（SUV）进行评价,病灶区SUV≥2．5为阳性。结果：PET／CT检查后,56例放射策略发生变化,其中14例（25．0％）改行其他治疗,12例（21．4％）将根治性放疗改为姑息性放疗,18例（32．1％）改变了照射靶区,12例（21．4％）调整了放疗剂量。结论：PET／CT为恶性肿瘤放疗前的全面评估和决策提供了更多更有效的临床信息,其功能显影和解剖影像同机融合的突出优势,明显提高了治疗效果,减少或减轻了并发症的发生。     

Breast Sparganosis Incidentally Detected by FDG PET/CT

Sparganosis is a rare, parasitic infection that is caused by the plercercoid tapeworm larvae of the genus Spirometra. Sparganosis is transmitted by ingestion of larvae-containing water or intermediate hosts, such as raw amphibians, and usually presented with a subcutaneous nodule in the abdominal wall, extremities, and genital organs. Among the various involved organs, the breast is a seldom encountered site for sparganosis. However, breast sparganosis has clinical importance, since it is generally presented with an indolent palpable mass that mimics malignancy, even without evidence of inflammation. Herein, we report a case of breast sparganosis that was detected incidentally by FDG PET/CT during staging work ups in a patient with gall bladder cancer.     

Non-enhanced CT versus contrast-enhanced CT in integrated PET/CT studies for nodal staging of rectal cancer

Purpose The purpose of the present study was to determine the diagnostic accuracy of non-enhanced CT and contrast-enhanced CT in integrated PET/CT studies for preoperative nodal staging of rectal cancer. Methods Retrospective analysis was performed in 53 patients with pathologically proven rectal cancer who had been referred for preoperative staging. All patients underwent integrated PET/CT consisting of non-enhanced and contrast-enhanced CT followed by whole-body fluorine-18-fluorodeoxyglucose ([¹⁸F]FDG) PET. Both non-enhanced and contrast-enhanced PET/CT images were evaluated separately by two observers in consensus. The reference standard was histopathologic results. For nodal staging of rectal cancer, we compared diagnostic accuracy on a per-patient basis between the two modalities. Results Nodal staging was correctly determined with non-enhanced studies in 37 patients (70%) and with contrast-enhanced studies in 42 patients (79%). On a per-patient basis, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of regional lymph node staging were 85%, 68%, 83%, 72%, and 79%, respectively, with contrast-enhanced studies, and 85%, 42%, 73%, 62%, and 70%, respectively, with non-enhanced studies. The difference in the accuracy of nodal staging between the two modalities was not significant (p = 0.063). Compared with non-enhanced studies, contrast-enhanced studies determined more correctly the status of pararectal lymph nodes (p = 0.002), internal iliac lymph nodes (p = 0.004), and obturator lymph nodes (p < 0.0001). Conclusion Contrast-enhanced PET/CT is superior to non-enhanced PET/CT for precise definition of regional nodal status in rectal cancer.     

PET/CT显像在乳腺癌疗效评价及预后中的作用

乳腺癌是危害全球妇女健康的最常见的恶性肿瘤。PET/CT的应用大大提高了乳腺癌的临床诊治率。PET/CT在评价治疗效果及术前早期识别出对反应无效的患者方面有着独到的优势。近年来，有研究发现，癌细胞表面分子标记，如雌激素受体、孕激素受体和人表皮生长因子受体2表达水平等可直接影响疾病的预后和治疗方案的制定。     

Role of respiratory-gated PET/CT for pancreatic tumors: A preliminary result

Purpose

The aim of this study is to ascertain role of respiratory-gated PET/CT for accurate diagnosis of pancreatic tumors.

Materials and methods

Prior to clinical study, the phantom study was performed to evaluate the impact of respiratory motion on lesion quantification. Twenty-two patients (mean age 65 years) with pancreatic tumors were enrolled. Pathological diagnoses by surgical specimens consisted of pancreatic cancer (n = 15) and benign intraductal papillary mucinous neoplasm (IPMN, n = 7). Whole-body scan of non-respiratory-gated PET/CT was performed at first, and subsequent respiratory-gated PET/CT for one bed position was performed. All PET/CT studies were performed prior to surgery. The SUV max obtained by non-respiratory-gated PET/CT and respiratory-gated PET/CT, and percent difference in SUVmax (%SUVmax) were compared.

Results

The profile curve of 5 respiratory bin image was most similar to that of static image. The third bin of 5 respiratory bin image showed highest FWHM (24.0 mm) and FWTM (32.7 mm). The mean SUVmax of pancreatic cancer was similar to that of benign IPMN on non-respiratory-gated PET/CT (p = 0.05), whereas significant difference was found between two groups on respiratory-gated PET/CT (p = 0.016). The mean %SUV of pancreatic cancer was greater than that of benign IPMN (p < 0.0001). Identification of the primary tumor in pancreatic head (n = 13, 59%) was improved by using respiratory-gated PET/CT because of minimal affection of physiological accumulation in duodenum.

Conclusion

Respiratory-gated PET/CT is a feasible technique for evaluation of pancreatic tumors and allows more accurate identification of pancreatic tumors compared with non-respiratory-gated PET/CT.     

Bone metastasis in patients with non-small cell lung cancer: The diagnostic role of F-18 FDG PET/CT

Purpose

To evaluate the performance of F-18 FDG PET/CT in the detection of bone metastasis in non-small cell lung cancer (NSCLC) patients.

Materials and methods

Three hundred and sixty-two consecutive NSCLC patients who underwent F-18 FDG PET/CT scanning were retrospectively analyzed. Each image of PET/CT, combined CT, and PET was performed at 10 separate areas and interpreted blindly and separately. The sensitivity, specificity and accuracy of F-18 FDG PET/CT, combined CT and F-18 FDG PET were calculated and the results were statistically analyzed.

Results

Bone metastasis was confirmed in 82 patients with 331 positive segments based on the image findings and clinical follow-up. On patient-based analysis, the sensitivity of F-18 FDG PET/CT (93.9%) was significantly higher than those of combined CT (74.4%) and F-18 FDG PET (84.1%), respectively (p < 0.05). The overall specificity and accuracy of combined CT, F-18 FDG PET, and F-18 FDG PET/CT were 90.7%, 93.2%, 98.9% and 87.0%, 91.2%, and 97.8%, respectively (compared with PET/CT, p < 0.05). On segment-based analysis, the sensitivity of the three modalities were 79.5%, 94.3%, and 98.8%, respectively (compared with PET/CT, p < 0.05). The overall specificity and accuracy of the three modalities were 87.9%, 89.2%, 98.6% and 84.5%, 91.2%, 98.7%, respectively (compared with PET/CT, p < 0.05).

Conclusion

F-18 FDG PET/CT is superior to F-18 FDG PET or combined CT in detecting bone metastasis of NSCLC patients because of the complementation of CT and PET. It is worth noting that the added value of F-18 FDG PET/CT may beneficially impact the clinical management of NSCLC.     

Low-dose non-enhanced CT versus full-dose contrast-enhanced CT in integrated PET/CT scans for diagnosing ovarian cancer recurrence

Objective

To evaluate low-dose non-enhanced CT (ldCT) and full-dose contrast-enhanced CT (ceCT) in integrated ¹⁸F-fluorodeoxyglucose (FDG)-PET/CT studies for restaging of ovarian cancer.

Materials and methods

One hundred and twenty women who had undergone treatment for ovarian cancer underwent a conventional PET/CT scans with ldCT, and then ceCT. Two observers interpreted and decided in consensus on the PET/ldCT and PET/ceCT images by a 3-point scale (N: negative, E: equivocal, P: positive) per patient and lesion site. Final diagnoses were obtained by histopathological examinations, or clinical follow-up for at least 6 months.

Results

Patient-based analysis showed that the sensitivity, specificity, and accuracy of PET/ceCT was 86.9% (40/46), 95.9% (71/74), and 92.5% (111/120), respectively, whereas those of PET/ldCT were 78.3% (36/46), 95.0% (70/74), and 88.3% (106/120), respectively. All sensitivity, specificity, and accuracy significantly differed between two methods (McNemar test, p < 0.0005, p = 0.023, and p < 0.0001, respectively). The scales of detecting 104 recurrent lesion sites were N:14, E:6, P:84 for PET/ceCT, and N:15, E:17, P:72 for PET/ldCT, respectively. Eleven equivocal and one negative regions by PET/ldCT were correctly interpreted as positive by PET/ceCT.

Conclusion

PET/ceCT is a more accurate imaging modality with higher confidence for assessing ovarian cancer recurrence than PET/ldCT.     

Prospective evaluation of MRI,C-acetate PET/CT and contrast-enhanced CT for staging of bladder cancer

Purpose

To prospectively evaluate the diagnostic performance of magnetic resonance imaging (MRI), ¹¹C-acetate positron emission tomography/computed tomography (PET/CT) and contrast-enhanced CT for bladder cancer staging, using whole-mount pathologic review of radical cystectomy and pelvic lymph node specimens as the reference standard.

Materials and methods

The institutional review board approved this prospective study, which was compliant with the Health Insurance Portability and Accountability Act. Written informed consent was obtained from 16 patients with histologically confirmed bladder cancer who underwent MRI, ¹¹C-acetate PET/CT and contrast-enhanced CT before radical cystectomy and pelvic lymph node dissection. Before imaging 4/16 patients had received intravesical Bacillus Calmette-Guérin treatment, 6 had received systemic chemotherapy, 3 had received both and 3 had received neither. Measures of diagnostic performance including accuracy, sensitivity and specificity were estimated separately for each imaging modality.

Results

MRI correctly staged 56% of patients (9/16), overstaged 38% (6/16) and understaged 6% (1/16). CT correctly staged 50% of patients (8/16), overstaged 44% (7/16) and understaged 6% (1/16). In 9 patients, ¹¹C-acetate PET/CT showed uptake within the bladder wall; the uptake was true-positive in 7 patients and false-positive in 2 patients. Of the remaining 7 patients, 5 had true-negative and 2 had false-negative PET/CT results for cancer in the bladder wall. For all modalities, staging accuracy was reduced in patients with a history of prior intravesical and/or systemic chemotherapy.

Conclusion

In staging bladder cancer, MRI, ¹¹C-acetate PET/CT and CT displayed similar levels of accuracy. For all modalities, a history of intravesical and/or systemic chemotherapy affected staging accuracy.