Evaluation of fluorodeoxyglucose positron‐emission tomography with computed tomography for staging of urothelial carcinoma

Study Type – Diagnostic (case series)
Level of Evidence 4

OBJECTIVE

To investigate the role of ¹⁸F‐fluorodeoxyglusose positron‐emission tomography (FDG‐PET), combined with computed tomography (CT) and forced diuresis, in the staging and follow‐up of urothelial carcinoma (UC).

PATIENTS AND METHODS

We recruited 44 patients with muscle‐invasive urothelial bladder cancer (UBC) before radical cystectomy (RC), 19 under follow‐up after RC and seven after systemic chemotherapy. For those who had RC, histopathology was used as the reference standard to compare the sensitivity and specificity of FDG‐PET/CT and standard CT in detecting UBC and pelvic lymph node metastasis. Furthermore, 36 patients with ≥6 months of follow‐up imaging were considered to describe the progression of UC and extrapelvic positive FDG‐PET/CT images.

RESULTS

For the detection of primary UBC, FDG‐PET/CT was slightly more sensitive than CT (85% vs 77%) but less specific (25% vs 50%). For the detection of pelvic node metastasis FDG‐PET/CT was more sensitive than CT (57% vs 33%) with a specificity of 100% for both imaging techniques. In 20 patients, extrapelvic FDG‐PET/CT images showed suspected disease at the first evaluation. UC progressed in nine of the 10 patients who had synchronous multiple PET‐positive retroperitoneal or mediastinal lymph nodes, and in only two of the nine with unique hyperactive lesions in the lung. FDG‐PET/CT also detected a pT1G3 UC of the renal pelvis and all bone metastases detected by bone scintigraphy.

CONCLUSIONS

FDG‐PET/CT could replace standard CT and bone scintigraphy in the presurgical staging and monitoring of patients with UC after surgery or chemotherapy.     

Bone Scan or 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography; Which Modality Better Shows Bone Metastases of Breast Cancer?

Background

In this multicenter study, we aimed to compare concurrent ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) and bone scan results of breast cancer patient.

Patients and Methods

162 patients with breast cancer (158 female, 4 male; mean age 50.6 years) were included in the study. FDG PET/CT examination was performed in all patients, and concurrent bone scintigraphy in 68 patients. The results of FDG PET/CT and bone scan were compared.

Results

132 of the 162 patients were operated on because of breast cancer. 89 patients had metastasis, and 4 had recurrent disease according to FDG PET/CT results. Metastatic sites in order of frequency were lymph nodes, bone, lung, liver, adrenal gland, local skin or muscle, brain, and peritoneum (peritonitis carcinomatosa). The sensitivity, specificity, accuracy, and negative and positive predictive value of bone scintigraphy versus FDG PET/CT were 96 vs. 100%, 100 vs. 98%, 100 vs. 83%, 100 vs. 100%, and 90 vs. 100%, respectively.

Conclusion

Although the 2 modalities were in concordance with each other, in 5 (21%) cases, FDG PET/CT could not show bone metastasis which were detected on bone scintigraphy. Hence, bone scintigraphy was superior to FDG PET/CT in the determination of bone metastasis derived from breast cancer. However, FDG PET/CT should be considered for soft tissue metastasis.     

The diagnostic accuracy of 18F-fluorodeoxyglucose positron emission tomography and computed tomography in staging bladder cancer: a single-institution study and a systematic review with meta-analysis

Purpose

The purpose of this study was to assess the diagnostic accuracy of 18F-fluorodeoxyglucose with positron emission tomography and computed tomography (FDG–PET–CT) to predict nodal metastases in patients with bladder cancer (BC) scheduled to undergo radical cystectomy (RC).

Methods

We retrospectively reviewed records of patients diagnosed with BC and scheduled to undergo RC at our center from January 2011 through February 2015, who also underwent FDG–PET–CT at the time of diagnosis. All patients underwent RC and an extended pelvic lymph node dissection as the reference standard. The primary endpoints were the sensitivity, specificity and overall accuracy of FDG–PET–CT in detecting lymph node metastasis. We also examined its accuracy in identifying distant metastasis. In addition, we conducted a protocol-driven systematic review and meta-analysis of accuracy of FDG–PET–CT for preoperative staging of BC, as compared to CT alone, as reported in individual studies. To assess the methodological quality of eligible studies, we used the QUADAS-2 tool (a revised tool for the Quality Assessment of Diagnostic Accuracy Studies) and pooled diagnostic accuracy measures using Meta-DiSc statistical software.

Results

For detecting nodal metastases in 78 patients, the sensitivity of FDG–PET–CT was 0.56 (95 % CI 0.29–0.80) and the specificity, 0.98 (95 % CI 0.91–1.00). Pooled sensitivity and specificity for detecting lymph node metastasis were 0.57 and 0.95, respectively. Positive likelihood ratio was 9.02. All lesions that were suspicious for distant metastasis were found to be positive on biopsy.

Conclusion

FDG–PET–CT was more accurate than CT alone in staging BC in patients undergoing surgery. Standardization of FDG–PET–CT protocol and cost-effectiveness analysis are required before widespread implementation of this technology.

     

Detection of incidental colorectal tumours with 18F‐labelled 2‐fluoro‐2‐deoxyglucose positron emission tomography/computed tomography scans: results of a prospective study

Aim This study assessed the clinical significance of incidental colorectal 2‐fluoro‐2‐deoxyglucose (FDG) uptake using ¹⁸F‐FDG positron emission tomography/computed tomography (PET/CT) scans and evaluated the importance of colonoscopy when incidental colorectal FDG uptake was observed. Method A prospective study was designed and conducted at a single institution over a 2‐year period. In patients undergoing PET/CT scans, all with FDG uptake in the colorectum were assigned to have colonoscopy and biopsy. The value of PET/CT scanning was studied by comparison with the colonoscopy and biopsy results. Results Among 10 978 PET/CT scans, one or more focal uptakes of FDG in the colorectum were observed in 148 (1.35%) patients. In 136 valid patients, malignant colorectal tumours and polyps were found in 23.5% and 20.5%, respectively,, while the colon in the other 56% was normal. A higher false‐positive rate was found in the right colon compared with the distal colorectum (66.2%vs 36.7%, P = 0.004). A significant increase of the maximum standardized uptake (SUVmax) value was found among normal, polyps and cancer groups. Multivariate analysis revealed that SUVmax was the risk factor for predicting colorectal cancer or polyps and FDG uptake in the right colon was a negative predictive factor for finding cancers or polyps. Conclusions Our study proves the necessity of colonoscopy when incidental FDG uptake is found on PET/CT imaging. The false‐positive FDG uptake is more commonly observed in the right colon. Although the SUVmax value is higher in cancer patients, a high SUVmax value does not necessarily result in malignancies.     

The clinical advances of fluorine‐2‐D‐deoxyglucose – positron emission tomography/computed tomography in urological cancers

Fluorine‐18 labeled fluorine‐2‐D‐deoxyglucose (FDG) is the most frequently used positron emission tomography (PET) probe but it has certain limitations when used in urological cancers. The introduction of co‐registered PET and computed tomography (PET/CT) represents a major advance in technology and FDG‐PET/CT has now become the new standard. The diagnostic performance of FDG‐PET and PET/CT depends on the metabolic activity of tumor tissue, which is generally low in primary renal cell and prostate cancers and often in their metastatic deposits. In contrast, both seminomatous and nonseminomatous germ cell tumors are characterized by upregulated glucose metabolism with subsequently increased FDG uptake in tumor sites. Generally, the metabolic activity provides accurate information regarding the presence of a viable tumor, except in patients with residual mature teratoma. Although bladder cancer demonstrates sufficiently increased FDG uptake, primary tumors are difficult to identify due to the renal excretion of FDG. The accuracy of FDG‐PET/CT in metabolically active metastases is generally higher compared to conventional CT except for identifying small lung deposits. With disease progression and subsequent de‐differentiation of prostate cancer, castrate resistant disease is more likely to present with lesions that have increased glucose metabolism.     

Combined 18F‐fluorocholine and 18F‐fluoride positron emission tomography/computed tomography imaging for staging of high‐risk prostate cancer

Study Type – Diagnosis (cohort) Level of Evidence 2a What's known on the subject? and What does the study add? Positron emission tomography/computed tomography (PET/CT) with choline and fluoride for the detection of metastases in patients with prostate cancer have each been evaluated, with mixed results. Choline PET/CT has been evaluated against pelvic lymphadenectomy, generally with a low sensitivity but a high specificity; however, the study populations have been heterogenous. Fluoride PET/CT has been evaluated against other imaging methods, such as bone scan, single photon emission CT and MRI, and has been shown to have high specificity as well as sensitivity for bone metastases, but there are no studies with biopsy verification. This is the first study that evaluates the clinical use of both choline and fluoride PET/CT on the same patients in a well‐defined population of patients with high‐risk prostate cancer.

OBJECTIVE

• ? To investigate how often positron emission tomography/computed tomography (PET/CT) scans, with both ¹⁸F‐fluorocholine and ¹⁸F‐fluoride as markers, add clinically relevant information for patients with prostate cancer who have high‐risk tumours and a normal or inconclusive planar bone scan.

PATIENTS AND METHODS

• ? Patients with prostate cancer with prostate specific antigen (PSA) levels between 20 and 99 ng/mL and/or Gleason score 8–10 tumours, planned for treatment with curative intent based on routine staging with a negative or inconclusive bone scan, were further investigated with a ¹⁸F‐fluorocholine and a ¹⁸F‐fluoride PET/CT.
• ? None of the patients received hormonal therapy before the staging procedures were completed.

RESULTS

• ? For 50 of the 90 included patients (56%) one or both PET/CT scans indicated metastases.
• ? ¹⁸F‐fluorocholine PET/CT indicated lymph node metastases and/or bone metastases in 35 patients (39%).
• ? ¹⁸F‐fluoride PET/CT was suggestive for bone metastases in 37 patients (41%).
• ? In 18 patients (20%) the PET/CT scans indicated widespread metastases, leading to a change in therapy intent from curative to non‐curative.
• ? Of the patients with positive scans, 74% had Gleason score 8–10 tumours. Of the patients with Gleason score 8–10 tumours, 64% had positive scans.

CONCLUSIONS

• ? PET/CT scans with ¹⁸F‐fluorocholine and ¹⁸F‐fluoride commonly detect metastases in patients with high‐risk prostate cancer and a negative or inconclusive bone scan.
• ? For 20% of the patients the results of the PET/CT scans changed the treatment plan.

     

[18F]‐fluorocholine positron‐emission/computed tomography for lymph node staging of patients with prostate cancer: preliminary results of a prospective study

Study Type – Diagnostic (case series)
Level of Evidence 4

OBJECTIVES

To evaluate prospectively [¹⁸F]‐fluorocholine positron‐emission/computed tomography (FCH PET/CT) for lymph node staging of prostate cancer before intended curative therapy, and to determine whether imaging 15 or 60 min after radiotracer injection is preferable.

PATIENTS AND METHODS

In all, 25 consecutive patients with newly diagnosed prostate cancer (Gleason score >6, and/or a prostate‐specific antigen level of >10 ng/mL, and/or T3 cancer) were scanned before lymphadenectomy. Each patient was assessed twice with imaging, at 15 and 60 min after the injection with FCH. Images were compared with the results of histopathological examination of the surgically removed lymph nodes. Maximum standardized uptake values (SUV_max) at 15 and 60 min were also compared.

RESULTS

Histopathologically, metastases were present in removed lymph nodes from three patients. FCH PET/CT showed a high radiotracer uptake in four patients, the former three and a fourth. The sensitivity, specificity, positive and negative predictive value of FCH PET/CT for patient based lymph node staging of prostate cancer were 100%, 95%, 75% and 100%, respectively; the corresponding 95% confidence intervals were 29.2–100%, 77.2–99.9%, 19.4–99.4% and 83.9–100%, respectively. Values of SUV_max at early and late imaging were not significantly different.

CONCLUSIONS

This small series supports the use of FCH PET/CT as a tool for lymph node staging of patients with prostate cancer. Values of SUV_max at early and late imaging did not differ. However, larger prospective studies are needed to validate these findings.     

Beurteilung von Residualtumoren nach Systemtherapie des metastasierten Seminoms

Background

Meta-analysis evaluating the accuracy and sensitivity of FDG (2-[¹⁸F]-fluoro-2-deoxy-D-glucose) positron emission tomography (PET) to predict viable residual tumours in patients with metastatic seminoma.

Material and methods

Altogether 5 studies with 130 patients were identified. Both FDG PET and the size of the residual lesions on conventional computed tomography (CT; lesions either ?? or > 3 cm) were correlated with the presence or absence of viable residual tumour.

Results

The specificity (92 vs 59%), sensitivity (72 vs 63%), positive (70 vs 28%) and negative (93 vs 86%) predictive value of FDG PET were superior to data obtained by assessing residual tumour size (either ?? or > 3 cm) applying CT scans alone.

Conclusion

In view of the data currently available, FDG PET seems to be a clinically useful predictor of viable tumour in post-chemotherapy residuals of pure seminoma.     

18F‐FDG‐PET/CT predicts early tumor recurrence in living donor liver transplantation for hepatocellular carcinoma

The prognosis including ¹⁸F‐fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F‐FDG‐PET/CT) for the early recurrence for hepatocellular carcinoma (HCC) after living donor liver transplantation (LDLT) was not well established. Consecutive patients who underwent ¹⁸F‐FDG‐PET/CT and subsequent LDLT for HCC from March 2005 to June 2011 were enrolled. The 191 patients with a median follow‐up of 26.1 months were evaluated. There were 20 patients (10.5%) with early recurrence (≤6 months), 18 patients (9.4%) with late recurrence (>6 months), and 153 patients (80.1%) with no recurrence. Fifty‐five patients (28.8%) displayed increased PET/CT tumor uptake. Three‐year overall and disease‐free survival for PET/CT‐positive patients were 65.5% and 57.1%, respectively, while PET/CT‐negative patients showed respective values of 89.8% and 86.8% (P = 0.001 vs. P < 0.001). Tumor variables associated with PET/CT‐positive finding were preoperative AFP level, Milan, UCSF criteria, maximum tumor size, total tumor size, differentiation, vascular invasion, and serosal invasion. PET/CT‐positive status was identified as an independent prognostic factor for disease‐free survival influencing early recurrence in multivariable analysis (HR 3.945, 95% CI 1.196–13.016, P = 0.024). ¹⁸F‐FDG‐PET/CT is an independent and significant predictor of early tumor recurrence in LDLT for HCC.     

FDG-PET/CT for the Preoperative Lymph Node Staging of Invasive Bladder Cancer

Background

Locoregional lymph node metastasis is an important prognostic factor in patients with bladder cancer. Multimodal treatment, depending on preoperative stage, may improve survival. The standard imaging modalities for staging (computed tomography [CT] or magnetic resonance imaging [MRI]) have an accuracy range of 70–90% for lymph node staging. A more accurate preoperative diagnostic test could improve survival rates even more.

Objective

To determine whether the use of 2-deoxy-2 [F] fluoro-D-glucose (FDG) positron emission tomography (PET) in combination with CT (FDG-PET/CT) can increase the reliability of preoperative lymph node staging in patients with nonmetastatic invasive bladder cancer (T2 or higher, M0) or recurrent high-risk superficial disease (T1G3 with or without Tis, M0).

Design, setting, and participants

Fifty-one patients underwent a preoperative FDG-PET/CT between April 2004 and December 2007. Independent of the result for lymph node status, all patients underwent a radical cystectomy and an extended lymphadenectomy. The FDG-PET/CT and CT results were compared with the definitive pathologic results.

Measurements

Among the 51 patients, 13 patients had metastatically involved locoregional lymph nodes, diagnosed on histopathology. In six patients, these nodes demonstrated increased FDG uptake on PET. In seven patients, PET/CT did not diagnose the positive lymph nodes. PET/CT was false positive in one patient.

Results and limitations

For the diagnosis of node-positive disease, the accuracy, the sensitivity, and the specificity of FDG-PET/CT were 84%, 46%, and 97%, respectively. When analysing the results of CT alone, there was accuracy of 80%, sensitivity of 46%, and specificity of 92%. The use of FDG-PET/CT is hampered by technical limitations.

Conclusions

We found no advantage for combined FDG-PET/CT over CT alone for lymph node staging of invasive bladder cancer or recurrent high-risk superficial disease.     

Tumor localization and biochemical response to cure in tumor‐induced osteomalacia

Tumor‐induced osteomalacia (TIO) is a rare disorder of phosphate wasting due to fibroblast growth factor‐23 (FGF23)‐secreting tumors that are often difficult to locate. We present a systematic approach to tumor localization and postoperative biochemical changes in 31 subjects with TIO. All had failed either initial localization, or relocalization (in case of recurrence or metastases) at outside institutions. Functional imaging with ¹¹¹Indium‐octreotide with single photon emission computed tomography (octreo‐SPECT or SPECT/CT), and ¹⁸fluorodeoxyglucose positron emission tomography/CT (FDG‐PET/CT) were performed, followed by anatomic imaging (CT, MRI). Selective venous sampling (VS) was performed when multiple suspicious lesions were identified or high surgical risk was a concern. Tumors were localized in 20 of 31 subjects (64.5%). Nineteen of 20 subjects underwent octreo‐SPECT imaging, and 16 of 20 FDG‐PET/CT imaging. Eighteen of 19 (95%) were positive on octreo‐SPECT, and 14 of 16 (88%) on FDG‐PET/CT. Twelve of 20 subjects underwent VS; 10 of 12 (83%) were positive. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were as follows: sensitivity = 0.95, specificity = 0.64, PPV = 0.82, and NPV = 0.88 for octreo‐SPECT; sensitivity = 0.88, specificity = 0.36, PPV = 0.62, and NPV = 0.50 for FDG‐PET/CT. Fifteen subjects had their tumor resected at our institution, and were disease‐free at last follow‐up. Serum phosphorus returned to normal in all subjects within 1 to 5 days. In 10 subjects who were followed for at least 7 days postoperatively, intact FGF23 (iFGF23) decreased to near undetectable within hours and returned to the normal range within 5 days. C‐terminal FGF23 (cFGF23) decreased immediately but remained elevated, yielding a markedly elevated cFGF23/iFGF23 ratio. Serum 1,25‐dihydroxyvitamin D₃ (1,25D) rose and exceeded the normal range. In this systematic approach to tumor localization in TIO, octreo‐SPECT was more sensitive and specific, but in many cases FDG‐PET/CT was complementary. VS can discriminate between multiple suspicious lesions and increase certainty prior to surgery. Sustained elevations in cFGF23 and 1,25D were observed, suggesting novel regulation of FGF23 processing and 1,25D generation.     

Significant increase in detection of prostate cancer recurrence following radical prostatectomy with an early imaging acquisition protocol with <Superscript>18</Superscript>F-fluorocholine positron emission tomography/computed tomography

Purpose

To highlight a new imaging acquisition protocol during ¹⁸F-fluorocholine PET/CT in patients with biochemical recurrence after RP.

Methods

A total of 146 patients with PSA levels between 0.2 and 1 ng/ml with negative conventional imaging who did not receive salvage treatment were prospectively enrolled. Imaging acquisition protocol included an early dynamic phase (1–8 min), a conventional whole body (10–20 min), and a late phase (30–40 min). Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were measured. Univariable and multivariable analyses were performed to identify independent predictors of positive PET/CT.

Results

The median trigger PSA was 0.6 ng/ml (IQR 0.43–0.76). Median PSA doubling time (PSA DT) was 7.91 months (IQR 4.42–11.3); median PSA velocity (PSAV) was 0.02 ng/ml per month (IQR 0.02–0.04). Overall, ¹⁸F-fluorocholine PET/CT was positive in 111 of 146 patients (76 %). Out of 111 positive examinations, 80 (72.1 %) were positive only in the early dynamic phase. Sensitivity, specificity, PPV, NPV, and accuracy were 78.9, 76.9, 97.2, 26.3, and 78.7 %, respectively. At multivariable logistic regression, trigger PSA ≥ 0.6 ng/ml [odds ratio (OR) 3.13; p = 0.001] and PSAV ≥ 0.04 ng/ml per month (OR 4.95; p = 0.004) were independent predictors of positive PET/CT. The low NPV remains the main limitation of PET/CT in this setting of patients.

Conclusions

The increased sensitivity, thanks to the early imaging acquisition protocol, makes ¹⁸F-fluorocholine PET/CT an attractive tool to detect prostate cancer recurrences in patients with a PSA level <1 ng/ml.

     

The value of 18F‐FDG PET/CT in diagnosing and localising deep sternal wound infection to guide surgical debridement

Deep sternal wound infection (DSWI) is a severe complication in patients after open heart surgery (OHS). But there is a lack of appropriate imaging tool to detect the infection sites, which may lead to incomplete debridement. The present study aims to investigate the value of ¹⁸F‐fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F‐FDG PET/CT) in comparison with CT scan in diagnosing and localising DSWI. A total of 102 patients with DSWI after OHS were retrospectively collected from January 2012 to December 2017 in our hospital. All the patients had surgical debridements for DSWI with pretreatment imaging of either ¹⁸F‐FDG PET/CT or CT scan. The sensitivity, specificity, and accuracy of localising infection sites were compared between PET/CT and CT groups, with surgical, microbiological, and histopathological findings as the gold standard. The length of hospital stays and the rate of recurrence were also compared. Ten patients in the PET/CT group had a follow‐up PET/CT scan after debridement, and the correlations between the changes of PET/CT findings and surgical outcomes were analysed. ¹⁸F‐FDG PET/CT is more accurate than CT in diagnosing and localising DSWI after OHS, which leads to a more successful surgical debridement with a lower rate of recurrence and a shorter length of hospital stay. In addition, follow‐up PET/CT after debridement could evaluate the treatment effect.     

FGD-PET in the follow-up of recurrent colorectal cancer

Objective The current methods of detection of recurrent colorectal cancer after surgical treatment are inaccurate using conventional imaging. This study set out to detect early recurrence by means of PET in patients treated surgically for colorectal cancer by curative resection. Methods Thirty‐one disease‐free patients were recruited and underwent FDG‐PET. The results were verified by clinical, surgical and radiological follow up and/or biopsy to evaluate the accuracy for detecting recurrence. Results PET detected 6 sites of increased activity in 5 patients. Three of these underwent surgery. One was false positive with no evident tumour and two underwent an hepatic resection with removal of a homental metastasis. The sensitivity was 100% and specificity 83.3%. Clinical management was altered in two cases (6.4%). Conclusions This study demostrates that PET is more accurate than conventional imaging for the evaluation of recurrence in colorectal cancer patients. FDG‐PET should be considered in the follow‐up of patients after treatment for colorectal cancer in addition to other imaging methods.     

Findings of fat‐suppressed T2‐weighted and diffusion‐weighted magnetic resonance imaging in the diagnosis of non‐palpable testes

Study Type – Diagnostic (exploratory cohort)
Level of Evidence 2b What’s known on the subject? and What does the study add? Both conventional magnetic resonance imaging (MRI) and ultrasonography (US) have been used for children with non‐palpable testes to facilitate a preoperative diagnosis, but the accuracy of these examinations was not satisfactory. In the present study, to improve the diagnostic accuracy of non‐palpable testes by MRI examination, we employed fat‐suppressed T2‐weighted imaging and DWI, as well as conventional MRI. Additional MRI assessments are useful methods to improve the accuracy of diagnosing non‐palpable testes.

OBJECTIVE

To evaluate the magnetic resonance imaging (MRI) findings, diagnostic accuracy and clinical usefulness of fat‐suppressed T2‐weighted and diffusion‐weighted imaging (DWI) in the management of non‐palpable testes.

PATIENTS AND METHODS

In all, 56 children (63 non‐palpable testes) aged 8 months–11 years (mean 24.7 months) with non‐palpable testes were enrolled. T1‐ and T2‐weighted imaging, as well as fat‐suppressed T2‐weighted imaging and DWI were performed during MRI examination, and the imaging results were compared with surgical findings.

RESULTS

In the 63 non‐palpable testes, MRI identified 22% (14/63) as intra‐abdominal, 20% (13/63) as intra‐canalicular, 29% (18/63) as testicular nubbins, and 29% (18/63) as unidentifiable. Although it was difficult to confirm their presence in the abdominal cavity using T1‐ and T2‐weighted imaging alone, additional assessment, including fat‐suppressed T2‐weighted imaging and DWI facilitated the detection of intra‐abdominal testes more easily because they were imaged at a markedly higher signal intensity. The sensitivity, specificity and positive and negative predictive values for the MRI vs the operative findings were 100, 97.3, 96.3, and 100%, respectively. The overall prediction accuracy was 98.4%.

CONCLUSION

Additional MRI assessments, fat‐suppressed T2‐weighted imaging and DWI are useful examinations to improve the preoperative diagnostic accuracy of non‐palpable testes.     

Diagnostic efficacy of [11C]choline positron emission tomography/computed tomography compared with conventional computed tomography in lymph node staging of patients with bladder cancer prior to radical cystectomy

Background

Current imaging techniques are of limited value for lymph node (LN) staging in bladder cancer (BCa) patients scheduled for radical cystectomy (RC).

Objective

Evaluate the diagnostic efficacy of [11C]choline positron emission tomography in combination with computed tomography (PET/CT) for LN staging of patients with BCa scheduled for RC and compare that efficacy with the diagnostic efficacy of CT and the gold standard of histopathologic evaluation.

Design, setting, and participants

From June 2004 to May 2007, 44 patients with localized BCa were staged with [11C]choline PET with low-dose CT for attenuation correction and simultaneous intravenous and rectal contrast-enhanced diagnostic CT before RC and pelvic lymph node dissection (PLND). LNs were dissected from the internal and external iliac arteries up to the origin of the inferior mesentery artery according to a template with 14 predefined anatomic fields.

Intervention

Diagnostic [11C]choline PET/CT before RC and regional LN dissection.

Measurements

Histopathologic findings of resected LN were correlated with the results of [11C]choline PET/CT and CT alone in a patient- and field-based manner. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of [11C]choline PET/CT and CT were assessed.

Results and limitations

LN metastases were found in 12 of 44 patients (27%). On patient-based analysis, sensitivity, specificity, PPV, NPV, and accuracy for [11C]choline PET/CT were calculated as 58%, 66%, 39%, 81%, and 64%, respectively; and for CT the calculated percentages were 75%, 56%, 39%, 86%, and 61%, respectively. Twenty-five of 471 dissected LN fields (5%) showed metastases. On field-based analysis, sensitivity, specificity, PPV, NPV, and accuracy for [11C]choline PET/CT were 28%, 95%, 21%, 96%, and 91%, respectively; for CT, the calculated percentages were 39%, 92%, 20%, 96%, and 90%, respectively. Limitations of this study are small patient number and the fact that not all patients underwent extensive PLND.

Conclusions

In patients with BCa who were scheduled for RC, preoperative LN staging with [11C]choline PET/CT was not able to improve diagnostic efficacy compared with conventional CT alone.     

18F-Fluoroethylcholine PET/CT Identifies Lymph Node Metastasis in Patients with Prostate-Specific Antigen Failure After Radical Prostatectomy but Underestimates Its Extent

Background

The detection of lymph node metastases (LNMs) is one of the biggest challenges in imaging in urology.

Objective

To evaluate the accuracy of combined 18F–fluoroethylcholine (FEC) positron emission tomography (PET)/computed tomography (CT) in the detection of LNMs in prostate cancer (PCa) patients with rising prostate-specific antigen (PSA) level after radical prostatectomy.

Design, settings, and participants

From June 2005 until November 2011, 56 PCa patients with biochemical recurrence after radical prostatectomy underwent bilateral pelvic and/or retroperitoneal lymphadenectomy based on a positive 18F-FEC PET/CT scan.

Outcome measurements and statistical analysis

The findings of PET/CT were compared with the histologic results.

Results and limitations

Median PSA value at the time of 18F-FEC PET/CT analysis was 6.0 ng/ml (interquartile range: 1.7–9.4 ng/ml). In 48 of 56 (85.7%) patients with positive 18F-FEC PET/CT findings, histologic examination confirmed the presence of PCa LNMs. Of 1149 lymph nodes that were removed and histologically evaluated, 282 (24.5%) harbored metastasis. The mean number of lymph nodes removed per surgical procedure was 21 (standard deviation: ±18.3). A lesion-based analysis yielded 18F-FEC PET/CT sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 39.7%, 95.8%, 75.7%, and 83.0%, respectively.A site-based analysis yielded sensitivity, specificity, PPV, and NPV of 68.4%, 73.3%, 81.3%, and 57.9%, respectively. Patients with negative PET/CT did not undergo surgery, thus sensitivity, specificity, and negative predictive value on a patient basis could not be calculated.

Conclusions

A positive 18F-FEC PET/CT result correctly predicted the presence of LNM in the majority of PCa patients with biochemical failure after radical prostatectomy but did not allow for localization of all metastatic lymph nodes and therefore was not adequately accurate for the precise estimation of extent of nodal recurrence in these patients.     

Positive margins after nephron‐sparing surgery for renal cell carcinoma: long‐term follow‐up of patients on active surveillance

Study Type – Therapy (case series)
Level of Evidence 4

OBJECTIVE

To analyse our long‐term oncological outcomes with active surveillance in patients with positive surgical margins (PSMs) after nephron‐sparing surgery (NSS) for renal cell carcinoma (RCC), as this situation is a difficult therapeutic dilemma.

PATIENTS AND METHODS

We performed open NSS for renal masses with frozen‐section analysis of any suspicious zone of the surgical bed, followed by extensive argon‐beam coagulation. In patients where the final histopathological examination of the renal mass revealed PSMs, follow‐up consisted of computed tomography (CT) every 6 months in the first 2 years and then annually up to 5 years, and thereafter we alternated ultrasonography with CT.

RESULTS

From 1995 to 2003 we had 11 cases of microscopic definitive PSMs after NSS for RCC. Two patients required nephrectomy (one for postoperative bleeding and another as an elective procedure), so nine were followed. These patients were either operated under elective (seven) or imperative (two) conditions. The histological subtype was clear cell carcinoma in three, papillary in two, chromophobe in two and hybrid oncocytic RCC in two, with a Furhman grade of 2 in six and 3 in three. The mean size was 31.4 mm, and the stage was pT1a in six, pT1b in one and pT3a in two. After a median follow‐up of 80.5 months, there was no local recurrence or distant progression.

CONCLUSIONS

In our experience, microscopic PSMs in NSS specimens can be managed conservatively with active surveillance, achieving excellent results and avoiding extensive reoperation without compromising long‐term oncological outcomes.     

18FDG PET/CT在术前检测食管癌淋巴结转移及分期中的应用

目的观察^18FDG PET/CT在术前检测食管癌淋巴结转移及分期的临床应用价值.方法随机选择拟行手术治疗的食管癌病人30例,术前1周内行^18FDG PET/CT检查,12例病人同期行CT增强扫描,术前均不接受放化疗,根据术后病理对比PET/CT与CT诊断食管癌淋巴结转移及确定淋巴结分期的价值.结果22例存在淋巴结转移,共切取并分离淋巴结243枚,转移淋巴结49枚.PET/CT诊断淋巴结转移的敏感性、特异性、准确性分别为93.9%、91.2%、91.8%,CT分别为40.8%、96.9%、85.6%;PET/CT阳性与阴性预测值分别为73.0%,98.3%,CT为76.9%,86.6%.PET/CT确定淋巴结分期的敏感性、特异性、准确性分别为95.5%、62.5%、86.7%,CT分别为72.7%、75.0%、73.3%.结论18FDG PET/CT图像融合技术诊断食管癌淋巴结转移及确定淋巴结分期临床应用价值优于CT.     

Role of Fusion of Prone FDG‐PET and Magnetic Resonance Imaging of the Breasts in the Evaluation of Breast Cancer

Abstract: The purpose of this study is to report further about the statistically significant results from a prospective study, which suggests that fusion of prone F‐18 Fluoro‐deoxy‐glucose (FDG) positron emission tomography (PET) and magnetic resonance (MR) breast scans increases the positive predictive value (PPV) and specificity for patients in whom the MR outcome alone would be nonspecific. Thirty‐six women (mean age, 43 years; range, 24–65 years) with 90 lesions detected on MR consented to undergo a FDG‐PET scan. Two blinded readers evaluated the MR and the computer tomography (CT) attenuation‐corrected prone FDG‐PET scans side‐by‐side, then after the volumes were superimposed (fused). A semiautomatic, landmark‐based program was used to perform nonrigid fusion. Pathology and radiologic follow‐up were used as the reference standard. The sensitivity, specificity, PPV, negative predictive value (NPV), and accuracy (with 95% confidence intervals) for MR alone, FDG‐PET alone, and fused MR and FDG‐PET were calculated. The median lesion size measured from the MR was 2.5 cm (range, 0.5–10 cm). Histologically, 56 lesions were malignant, and 15 were benign. Nineteen lesions were benign after 20–47 months of clinical and radiologic surveillance. The sensitivity of MR alone was 95%, FDG‐PET alone was 57%, and fusion was 83%. The increase in PPV from 77% in MR alone to 98% when fused and the increase in specificity from 53% to 97% were statistically significant (p < 0.05). The false‐negative rate on FDG‐PET alone was 26.7%, and after fusion this number was reduced to 9%. FDG‐PET and MR fusions were helpful in selecting which lesion to biopsy, especially in women with multiple suspicious MR breast lesions.