Diagnostic value of 18F-FDG PET/CT in patients with TENIS syndrome: correlation with thyroglobulin levels

Objective

The aim of the study was to disclose the place of ¹⁸F-FDG PET/CT to predict recurrent disease in patients with differentiated thyroid cancer (DTC), negative radioiodine whole-body scan (WBS) and high serum thyroglobulin (Tg).

Methods

Seventy-one patients who underwent total thyroidectomy followed by radioactive iodine ablation and had negative radioiodine WBS but elevated Tg levels underwent PET/CT. They were followed up for 6–50 months (median 23) for the occurence of recurrent disease as detected by either clinical findings, other imaging modalities or histopathological examination. The place of PET/CT findings at baseline to predict the presence of recurrent disease was evaluated. Correlation between PET/CT findings and Tg levels was examined and a threshold for Tg level above which the predictive value of PET/CT was highest was determined.

Results

PET/CT was positive for recurrent disease in 38 (53.5 %) patients. The sensitivity, specificity, PPV, NPV and diagnostic accuracy of PET/CT to predict the occurence of recurrent disease at follow-up were 68.8, 78.3, 86.8, 54.5 and 71.9 %, respectively. The sensitivity, accuracy and PPV of PET/CT increased with increasing Tg levels. The highest diagnostic accuracy of PET/CT, with a sensitivity of 76.2 % and a specificity of 100 % to detect recurrent disease appeared to be at a Tg level greater than 29 ng/mL.

Conclusion

Our findings suggest that ¹⁸F-FDG-PET/CT is a valuable tool to predict the occurence of recurrent disease in patients with DTC, negative WBS and elevated Tg levels. PET/CT positivity has been shown to be strongly and positively correlated with Tg levels in this patient subset.     

18F-FDG PET/CT impact on testicular tumours clinical management

Purpose

Testicular tumour is the most common malignancy in young men. The diagnostic work-up is mainly based on morphological imaging. The aim of our study was to evaluate the clinical impact of ¹⁸F-FDG PET/CT in patients with testicular tumour.

Methods

We retrospectively evaluated all patients studied by ¹⁸F-FDG PET/CT at our centre. Inclusion criteria were: pathological confirmation of testicular tumour, contrast-enhanced CT scan performed within a month of the PET/CT scan, and clinical/imaging follow-up performed at the Oncology Unit of our hospital. Overall, 56 patients were enrolled and 121 PET/CT scans were evaluated. ¹⁸F-FDG PET/CT was performed following standard procedures and the results were compared with clinical, imaging and follow-up data. Clinicians were contacted to enquire whether the PET/CT scan influenced the patient's management. Answers were scored as follows: start/continue chemotherapy or radiotherapy, indication for surgery of secondary lesions, and clinical surveillance.

Results

On a scan basis, 51 seminoma and 70 nonseminoma (NS) cases were reviewed. Of the 121 cases. 32 were found to be true-positive, 74 true-negative, 8 false-positive and 6 false-negative by PET/CT. PET/CT showed good sensitivity and specificity for seminoma lesion detection (92 % and 84 %, respectively), but its sensitivity was lower for NS forms (sensitivity and specificity 77 % and 95 %, respectively). The PET/CT scan influenced the clinical management of 47 of 51 seminomas (in 6 chemotherapy was started/continued, in 3 radiotherapy was started/continued, in 2 surgery of secondary lesions was performed, and in 36 clinical surveillance was considered appropriate), and 59 of 70 NS (in 18 therapy/surgery was started/continued, and in 41 clinical surveillance was considered appropriate).

Conclusion

Our preliminary data demonstrate the potential usefulness of PET/CT for the assessment of patients with testicular tumour. It provides valuable information for the clinical management, particularly for clinical surveillance, post-therapy assessment and when relapse is suspected.     

Role of 68Ga-DOTATOC PET/CT in initial evaluation of patients with suspected bronchopulmonary carcinoid

Purpose

The objective of this study was to evaluate the role of ⁶⁸Ga-DOTATOC positron emission tomography (PET)/CT scan in patients with suspected pulmonary carcinoid tumour and to compare its results with ¹⁸F-fluorodeoxyglucose (FDG) PET/CT scan.

Methods

In this prospective study, 32 patients (age 34.22?±?12.03 years; 53.1 % female) with clinical suspicion of bronchopulmonary carcinoid were evaluated with ⁶⁸Ga-DOTATOC PET/CT and ¹⁸F-FDG PET/CT. The two imaging modalities were compared, considering the tissue diagnosis as the reference standard.

Results

Based on the reference standard 26 cases were carcinoid tumours [21 typical carcinoids (TC) and 5 atypical carcinoids (AC)] and 6 cases were non-carcinoid tumours. The sensitivity, specificity and accuracy of ⁶⁸Ga-DOTATOC PET/CT in the diagnosis of pulmonary carcinoid tumour were 96.15, 100 and 96.87 % respectively, whereas those of ¹⁸F-FDG PET/CT were 78.26, 11.1 and 59.37 % respectively. The maximum standardised uptake value (SUV_max) of TC on ⁶⁸Ga-DOTATOC PET/CT scan ranged from 3.58 to 55, while that of AC ranged from 1.1 to 32.5. ¹⁸F-FDG PET/CT was true-positive in all cases of AC and false-negative in eight cases of TC (sensitivity for TC 61.9 % and for AC 100 %).

Conclusion

⁶⁸Ga-DOTATOC PET/CT is a useful imaging investigation for the evaluation of pulmonary carcinoids. ¹⁸F-FDG PET/CT scan suffers from low sensitivity and specificity in differentiating the pulmonary carcinoids from other tumours.     

Diagnostic accuracy of 18F-FDG PET/CT for detection of suspected recurrence in patients with oesophageal carcinoma

Purpose

To evaluate the role of ¹⁸F-FDG PET/CT in the detection of recurrence in patients with oesophageal carcinoma, suspected clinically or following conventional investigations.

Methods

This was a retrospective study. Data from 180 patients (age 56.3?±?10.4 years; 126 men, 54 women) with histopathologically proven oesophageal carcinoma (squamous cell 115, adenocarcinoma 59, neuroendocrine carcinoma 4, small cell 1, poorly differentiated 1) who had undergone 227 ¹⁸F-FDG PET/CT studies for suspected recurrence were analysed. Recurrence was suspected clinically or following conventional investigations. PET/CT images were revaluated by two nuclear medicine physicians in consensus. Findings were grouped into local, nodal and distant recurrence. Results were compared to those from contrast-enhanced (CE) CT when available (109 patients). Clinical/imaging follow-up (minimum 6 months) with histopathology (when available) was taken as the reference standard.

Results

Of the 227 ¹⁸F-FDG PET/CT studies,166 were positive and 61 were negative for recurrent disease. PET/CT showed local recurrence in 134, nodal recurrence in 115 and distant recurrence in 47, with more than one site of recurrence in 34. The PET/CT findings were true-positive in 153 studies, true-negative in 54, false-positive in 13 and false-negative in 7. The sensitivity of ¹⁸F-FDG PET/CT was 96 %, the specificity was 81 %, the positive and negative predictive values were 92 % and 89 %, respectively, and the accuracy was 91 %. PET/CT showed similar accuracy in patients with squamous cell carcinoma and in those with adenocarcinoma (P?=?0.181).¹⁸F-FDG PET/CT was more specific than CECT (67 % vs. 21 %; P?<?0.0001). PET/CT was superior to CECT for the detection of nodal recurrence (P?<?0.0001), but not local recurrence (P?=?0.093) or distant metastases (P?=?0.441).

Conclusion

¹⁸F-FDG PET/CT shows high accuracy in the detection of suspected recurrence in patients with oesophageal carcinoma. It is more specific than and is superior to CECT in the detection of nodal recurrence.     

Diagnostic accuracy of 18F-FDG PET/CT for detecting recurrence in patients with primary skeletal Ewing sarcoma

Purpose

To evaluate the diagnostic accuracy of ¹⁸F-FDG PET/CT for detecting recurrence in patients with primary skeletal Ewing sarcoma.

Methods

We retrospectively analysed data from 53 patients (age 20.1?±?10.5 years, 39 male) who had undergone 71 ¹⁸F-FDG PET/CT studies for suspected recurrence (52 studies) or for routine follow-up (19 studies) after primary therapy of skeletal Ewing sarcoma. ¹⁸F-FDG PET/CT studies were evaluated qualitatively and quantitatively (maximum standardized uptake value, SUVmax) by two nuclear medicine physicians in consensus. Sensitivity, specificity, predictive values and accuracy were calculated on per study basis. Clinical/imaging follow-up (minimum 6 months) and/or histopathology (when available) were taken as the reference standard.

Results

Of the total of 71 ¹⁸F-FDG PET/CT studies, 42 (59.1 %) were positive for recurrence and 29 (40.9 %) were negative for recurrence. Local recurrence was most common (38 studies) followed by bone metastasis (9 studies), and node and lung metastasis (2 studies each). Of the 71 studies, 38 were true-positive, 27 were true-negative, 4 were false-positive and 2 were false-negative. Overall per study based sensitivity was 95 %, specificity was 87 %, PPV was 90 %, NPV was 93 % and accuracy was 91.5 %. No significant difference was found in the accuracy of PET/CT between the suspected recurrence group and the routine follow-up group (94 % vs. 84 %; P?=?0.390). Overall mean lesion SUVmax was 7.8?±?4.1 (range 1.9–17.2). No site-based difference was found in SUVmax.

Conclusion

¹⁸F-FDG PET/CT demonstrates high diagnostic accuracy for detecting recurrence in patients with primary skeletal Ewing sarcoma, when it is suspected (clinically or on imaging) or during routine follow-up.     

Characterizing IgG4-related disease with 18F-FDG PET/CT: a prospective cohort study

Purpose

IgG4-related disease (IgG4-RD) is an increasingly recognized clinicopathological disorder with immune-mediated inflammatory lesions mimicking malignancies. A cohort study was prospectively designed to investigate the value of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in characterizing IgG4-RD.

Methods

Thirty-five patients diagnosed with IgG4-RD according to the consensus criteria were enrolled with informed consent. All patients underwent baseline ¹⁸F-FDG PET/CT evaluation. Among them, 29 patients underwent a second ¹⁸F-FDG PET/CT scan after 2 to 4 weeks of steroid-based therapy.

Results

All 35 patients were found with ¹⁸F-FDG-avid hypermetabolic lesion(s); 97.1 % (34/35) of these patients showed multi-organ involvement. Among the 35 patients, 71.4 % (25/35) patients were found with more organ involvement on ¹⁸F-FDG PET/CT than conventional evaluations including physical examination, ultrasonography, and computed tomography (CT). ¹⁸F-FDG PET/CT demonstrated specific image characteristics and pattern of IgG4-RD, including diffusely elevated ¹⁸F-FDG uptake in the pancreas and salivary glands, patchy lesions in the retroperitoneal region and vascular wall, and multi-organ involvement that cannot be interpreted as metastasis. Comprehensive understanding of all involvement aided the biopsy-site selection in seven patients and the recanalization of ureteral obstruction in five patients. After 2 to 4 weeks of steroid-based therapy at 40 mg to 50 mg prednisone per day, 72.4 % (21/29) of the patients showed complete remission, whereas the others exhibited > 81.8 % decrease in ¹⁸F-FDG uptake.

Conclusion

F-FDG PET/CT is a useful tool for assessing organ involvement, monitoring therapeutic response, and guiding interventional treatment of IgG4-RD. The image pattern is suggested to be updated into the consensus diagnostic criteria for IgG4-RD.     

18F-FDOPA PET/CT for detection of recurrence in patients with glioma: prospective comparison with 18F-FDG PET/CT

Purpose

Differentiation between recurrence and radiation necrosis in patients with glioma is crucial, since the two entities have completely different management and prognosis. The purpose of the present study was to compare the efficacies of ¹⁸F-FDG PET/CT and 3,4-dihydroxy-6-[¹⁸F]fluoro-phenylalanine (¹⁸F-FDOPA) PET/CT in detection of recurrent gliomas.

Methods

A total of 28 patients (age 38.82?±?1.25 years; 85.7 % men) with histopathologically proven glioma with clinical/imaging suspicion of recurrence were evaluated using ¹⁸F-FDG PET/CT and ¹⁸F-FDOPA PET/CT. ¹⁸F-FDG PET/CT and ¹⁸F-FDOPA PET/CT images were evaluated qualitatively and semiquantitatively. The combination of clinical follow-up, repeat imaging and/or biopsy (when available) was taken as the reference standard.

Results

Based on the reference standard, 21 patients were positive and 7 were negative for tumour recurrence. The sensitivity, specificity and accuracy of ¹⁸F-FDG PET/CT were 47.6 %, 100 % and 60.7 %, respectively, and those of ¹⁸F-FDOPA PET/CT were 100 %, 85.7 % and 96.4 %, respectively. The results of ¹⁸F-FDG PET/CT and ¹⁸F-FDOPA PET/CT were concordant in 57.1 % of patients (16 of 28) and discordant in 42.9 % (12 of 28). The difference in the findings between ¹⁸F-FDG PET/CT and ¹⁸F-FDOPA PET/CT was significant (P?=?0.0005, McNemar’s test). The difference was significant for low-grade tumours (P?=?0.0039) but not for high-grade tumours (P?=?0.250).

Conclusion

¹⁸F-FDOPA PET/CT is highly sensitive and specific for detection of recurrence in glioma patients. It is superior to ¹⁸F-FDG PET/CT for this purpose and is especially advantageous in patients with low-grade gliomas.     

Diuretic 18F-FDG PET/CT imaging for detection and locoregional staging of urinary bladder cancer: prospective evaluation of a novel technique

Purpose

Positron emission tomography/computed tomography (PET/CT) with ¹⁸F-fluorodeoxyglucose (FDG) has been used with limited success in the past in primary diagnosis and locoregional staging of urinary bladder cancer, mainly because of the pharmacokinetics of renal excretion of ¹⁸F-FDG. In the present prospective study, we have evaluated the potential application of diuretic ¹⁸F-FDG PET/CT in improving detection and locoregional staging of urinary bladder tumours.

Methods

Twenty-five patients suspected of having primary carcinoma of the urinary bladder were evaluated prospectively for diagnosis and staging. All of these 25 patients underwent conventional contrast-enhanced computed tomography (CECT) of the abdomen/pelvis and whole-body diuretic ¹⁸F-FDG PET/CT. In addition, pelvic PET/CT images were obtained using the special technique of forced diuresis using intravenous furosemide (20–40 mg). Of the 25 patients, 10 underwent radical cystectomy and 15 underwent transurethral resection of the bladder tumour (TURBT). Results of CECT and diuretic ¹⁸F-FDG PET/CT were compared considering histopathology as a reference standard.

Results

Of the 25 patients, CECT detected a primary tumour in 23 (sensitivity 92 %), while ¹⁸F-FDG PET/CT was positive in 24 patients (sensitivity 96 %). Mean size and maximum standardized uptake value of the bladder tumours were 3.33 cm (range 1.6–6.2) and 5.3 (range 1.3–11.7), respectively. Of the 25 patients, only 10 patients underwent radical cystectomy based on disease status on TURBT. Among those ten patients, nine had locoregional metastases. Among the nine patients who had positive lymph nodes for metastasis on histopathology, CECT and PET/CT scan had a sensitivity of 44 and 78 %, respectively. ¹⁸F-FDG PET/CT was found to be superior to CECT in the detection of the primary tumour and locoregional staging (p?<?0.05).

Conclusion

Diuretic ¹⁸F-FDG PET/CT is highly sensitive and specific and plays an important role in improving detection of the primary tumour and locoregional staging of urinary bladder tumours. Diuretic ¹⁸F-FDG PET/CT demonstrated a higher diagnostic value when compared with CECT in these patients.     

Usefulness of 18F-fluoride PET/CT in Breast Cancer Patients with Osteosclerotic Bone Metastases

Purpose

Bone metastasis is an important factor for the treatment and prognosis of breast cancer patients. Whole-body bone scintigraphy (WBBS) can evaluate skeletal metastases, and ¹⁸F-FDG PET/CT seems to exhibit high specificity and accuracy in detecting bone metastases. However, there is a limitation of ¹⁸F-FDG PET in assessing sclerotic bone metastases because some lesions may be undetectable. Recent studies showed that ¹⁸F-fluoride PET/CT is more sensitive than WBBS in detecting bone metastases. This study aims to evaluate the usefulness of ¹⁸F-fluoride PET/CT by comparing it with WBBS and ¹⁸F-FDG PET/CT in breast cancer patients with osteosclerotic skeletal metastases.

Materials and Methods

Nine breast cancer patients with suspected bone metastases (9 females; mean age ± SD, 55.6 ± 10.0 years) underwent ^99mTc-MDP WBBS, ¹⁸F-FDG PET/CT and ¹⁸F-fluoride PET/CT. Lesion-based analysis of five regions of the skeletons (skull, vertebral column, thoracic cage, pelvic bones and long bones of extremities) and patient-based analysis were performed.

Results

¹⁸F-fluoride PET/CT, ¹⁸F-FDG PET/CT and WBBS detected 49, 20 and 25 true metastases, respectively. Sensitivity, specificity, positive predictive value and negative predictive value of ¹⁸F-fluoride PET/CT were 94.2 %, 46.3 %, 57.7 % and 91.2 %, respectively. Most true metastatic lesions on ¹⁸F-fluoride PET/CT had osteosclerotic change (45/49, 91.8 %), and only four lesions showed osteolytic change. Most lesions on ¹⁸F-FDG PET/CT also demonstrated osteosclerotic change (17/20, 85.0 %) with three osteolytic lesions. All true metastatic lesions detected on WBBS and ¹⁸F-FDG PET/CT were identified on ¹⁸F-fluoride PET/CT.

Conclusion

¹⁸F-fluoride PET/CT is superior to WBBS or ¹⁸F-FDG PET/CT in detecting osteosclerotic metastatic lesions. ¹⁸F-fluoride PET/CT might be useful in evaluating osteosclerotic metastases in breast cancer patients.     

Clinical significance of 18F-α-methyl tyrosine PET/CT for the detection of bone marrow invasion in patients with oral squamous cell carcinoma: comparison with 18F-FDG PET/CT and MRI

Objective

L-3-[¹⁸F]-fluoro-α-methyl tyrosine (¹⁸F-FAMT) is an amino acid tracer for positron emission tomography/computed tomography (PET/CT) which specifically transported into cancer cells by L-type amino acid transporter 1 (LAT1). LAT1 overexpression in tumors is significantly correlated with cell proliferation and angiogenesis. ¹⁸F-FAMT PET/CT, fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) PET/CT and magnetic resonance imaging (MRI) were compared for their diagnostic performance in the detection of bone marrow invasion in patients with oral squamous cell carcinoma (OSCC).

Methods

Twenty-seven patients with OSCC on the upper or lower alveolar ridge underwent staging by MRI, ¹⁸F-FDG PET/CT and ¹⁸F-FAMT PET/CT studies before surgery. Post-surgical pathologic examination was used as the standard to determine the final diagnoses. The possibility of bone marrow invasion on MRI, ¹⁸F-FDG PET/CT and ¹⁸F-FAMT PET/CT were usually graded retrospectively into five-point score. Sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were calculated according to the obtained scores.

Results

As the sensitivity of ¹⁸F-FDG PET/CT was highest (100 %) among that of MRI (95 %) and ¹⁸F-FAMT PET/CT (90 %), the specificity of ¹⁸F-FAMT PET/CT was highest (85.7 %) among that of MRI (57 %) and ¹⁸F-FDG PET/CT (14.3 %). The size of pathological tumor was accorded with that detected by ¹⁸F-FAMT PET/CT and was smaller than that detected by ¹⁸F-FDG PET/CT (P < 0.01). Significant difference was not found between ¹⁸F-FAMT PET tumor volume and pathological tumor volume.

Conclusions

¹⁸F-FAMT PET/CT was useful and more specific than MRI or ¹⁸F-FDG PET/CT in the detection of bone marrow invasion of OSCC and may contribute to minimize the extent of resection in oral surgery patient.     

Initial clinical results of simultaneous 18F-FDG PET/MRI in comparison to 18F-FDG PET/CT in patients with head and neck cancer

Purpose

The aim of this study was to evaluate the diagnostic capability of simultaneous ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/MRI compared to ¹⁸F-FDG PET/CT as well as their single components in head and neck cancer patients.

Methods

In a prospective study 17 patients underwent ¹⁸F-FDG PET/CT for staging or follow-up and an additional ¹⁸F-FDG PET/MRI scan with whole-body imaging and dedicated examination of the neck. MRI, CT and PET images as well as PET/MRI and PET/CT examinations were evaluated independently and in a blinded fashion by two reader groups. Results were compared with the reference standard (final diagnosis determined in consensus using all available data including histology and follow-up). Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated.

Results

A total of 23 malignant tumours were found with the reference standard. PET/CT showed a sensitivity of 82.7 %, a specificity of 87.3 %, a PPV of 73.2 % and a NPV of 92.4 %. Corresponding values for PET/MRI were 80.5, 88.2, 75.6 and 92.5 %. No statistically significant difference in diagnostic capability could be found between PET/CT and PET/MRI. Evaluation of the PET part from PET/CT revealed highest sensitivity of 95.7 %, and MRI showed best specificity of 96.4 %. There was a high inter-rater agreement in all modalities (Cohen’s kappa 0.61–0.82).

Conclusion

PET/MRI of patients with head and neck cancer yielded good diagnostic capability, similar to PET/CT. Further studies on larger cohorts to prove these first results seem justified.     

18F-FDG PET/CT in HIV-related central nervous system pathology

Purpose

To evaluate the utility of ¹⁸F-FDG PET/CT in suspected cerebral pathology in HIV-infected individuals.

Methods

¹⁸F-FDG PET/CT scans from 29 HIV-infected individuals (29 brain scans, 22 whole-body scans) who presented with neurological symptoms and signs were retrospectively reviewed and compared with subsequent clinical investigations.

Results

The majority of patients (n?=?25) were referred to differentiate infection from malignant causes of cerebral pathology. Ten of the 11 patients with an eventual diagnosis of toxoplasmosis infection were correctly diagnosed by ¹⁸F-FDG PET/CT showing lesional uptake less than that of normal brain cortex (mean SUVmax 3.5, range 1.9 – 5.8). All five patients with a final diagnosis of primary central nervous system lymphoma (PCNSL) were correctly diagnosed by ¹⁸F-FDG PET/CT showing lesional uptake greater than that of normal brain cortex (mean SUVmax 18.8, range 12.4 – 29.9). Four of the five patients with ¹⁸F-FDG PET/CT features suggesting a vasculitic process had vasculitis confirmed as the final diagnosis. Three patients showed variable uptake in multiple cerebral lesions (including final diagnoses of tuberculosis and metastases from lung cancer in two patients) and there were four other miscellaneous diagnoses. In 12 patients biopsies were performed at sites guided by PET abnormality (7 brain, 5 lymph nodes) confirming or excluding significant disease in 11.

Conclusion

¹⁸F-FDG PET/CT is particularly useful for differentiating between infection and PCNSL in HIV-infected patients with a cerebral lesion on MRI or CT. ¹⁸F-FDG PET/CT was also a helpful tool in the diagnostic work-up of patients with other HIV-related cerebral pathology. Additional advantages of ¹⁸F-FDG PET/CT are the abilities to assess abnormally increased glucose metabolism in the body and to identify potential sites for biopsy.     

Therapeutic impact of 18F-FDG PET/CT in recurrent differentiated thyroid carcinoma

Purpose

¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT) has proved effective in detecting recurrent or metastatic differentiated thyroid carcinoma (DTC) in the follow-up of operated DTC patients with high thyroglobulin (Tg) levels and negative findings on radioiodine whole-body scan. The aim of this retrospective study was to assess the impact of PET/CT on the planning of appropriate treatment for known recurrent disease in operated DTC patients.

Materials and methods

The study concerned 44 consecutive DTC patients (36 papillary, 8 follicular), who underwent total thyroidectomy and thyroid remnant ablation with ¹³¹I and PET/CT. All patients had proven or strongly suspected recurrent disease judging from neck ultrasound (US) and fine-needle aspiration cytology, and detectable basal Tg levels.

Results

PET/CT findings were positive in 25/44 patients (56.81 %) and negative in 19. A positive PET/CT result predicted resectable tumour recurrences in 19/25 patients, but also detected additional tumour sites that prompted changes to the treatment plan in 6/25 patients (24 %). A negative PET/CT result led to clinical monitoring for 11/19 patients (57.89 %).

Conclusions

PET/CT can help select patients, who might benefit from a tailored therapy by improving the detection of local recurrences not apparent on neck US or metastases.     

Comparison of diagnostic ability between 99mTc-MDP bone scan and 18F-FDG PET/CT for bone metastasis in patients with small cell lung cancer

Objective

The aim of this study was to compare the diagnostic ability of ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) with that of ^99mTc-methylene diphosphonate (^99mTc-MDP) bone scan for bone metastasis in staging patients with small cell lung cancer (SCLC).

Methods

Ninety-five patients with SCLC who underwent both ¹⁸F-FDG PET/CT and ^99mTc-MDP bone scan for initial staging work-up were retrospectively enrolled. All ¹⁸F-FDG PET/CT and bone scan images were visually assessed. Bone metastasis was confirmed by histopathological results and all available clinical information.

Results

Of 95 patients with SCLC, metastatic bone lesions were found in 30 patients, and 84 metastatic lesions were evaluated on a lesion-basis analysis. The sensitivity of ¹⁸F-FDG PET/CT was 100?% on a per-patient basis and 87?% on a per-lesion basis, and there was no false-positive lesion on PET/CT images. In contrast, the sensitivity of the bone scan was 37?% on a per-patient basis and 29?% on a per-lesion basis. The bone scan showed 11 false-positive lesions. The bone scan detected two metastatic lesions that were not detected by PET/CT, which were outside the region scanned by PET/CT. On follow-up bone scan, 21 lesions that were not detected by the initial bone scan but were detected by PET/CT were newly detected.

Conclusions

In patients with SCLC, ¹⁸F-FDG PET/CT showed higher detection rate of bone metastasis than ^99mTc-MDP bone scan. Thus, ¹⁸F-FDG PET/CT can replace bone scan in staging patients with SCLC.     

Relations Between Pathological Markers and Radioiodine Scan and 18F-FDG PET/CT Findings in Papillary Thyroid Cancer Patients With Recurrent Cervical Nodal Metastases

Purpose

The aim of this study was to investigate relationships between the immunohistochemical results and radioiodine scan and ¹⁸F-FDG PET findings in papillary thyroid cancer (PTC) patients with recurrent cervical nodal metastases.

Methods

A total of 46 PTC patients who had undergone a radioiodine scan and/or ¹⁸F-FDG PET/CT and a subsequent operation on recurrent cervical lymph nodes were enrolled. Twenty-seven patients underwent ¹⁸F-FDG PET/CT, 8 underwent radioiodine scans, and 11 underwent both scans. In all surgical specimens, the immunoexpressions of thyroglobulin (Tg), sodium-iodide symporter (NIS), glucose transporter 1 (Glut-1), and somatostatin receptor 1 and 2A (SSTR1 and SSTR2A) were assessed, and associations between these expressions and radioiodine scan and ¹⁸F-FDG PET findings were evaluated.

Results

Of the 38 patients who underwent ¹⁸F-FDG PET/CT, all patients with weak Tg expression had positive ¹⁸F-FDG uptake, while only 45 % of the patients with moderate or strong Tg expression showed positive uptake (p = 0.01). The proportion of patients with positive ¹⁸F-FDG uptake increased as the degree of Glut-1 expression with luminal accentuation increased. Of the 19 patients who underwent a radioiodine scan, the proportion with positive radioiodine uptake was greater among patients with strong NIS and SSTR2A expression than among patients expressing these markers at weak levels (p = 0.04 for all). All three patients with weak Tg expression were negative for radioiodine uptake.

Conclusion

The ¹⁸F-FDG uptakes of recurrent cervical nodes are related to strong Glut-1 expression with luminal accentuation and weak Tg expression, whereas radioiodine uptake is related to the strong expressions of NIS and SSTR2A.     

Correlation of 18F-FDG PET/CT assessments with disease activity and markers of inflammation in patients with early rheumatoid arthritis following the initiation of combination therapy with triple oral antirheumatic drugs

Purpose

This study evaluated the potential of functional imaging to monitor disease activity and response to treatment with disease-modifying antirheumatic drugs (DMARD) in DMARD-naive patients with early rheumatoid arthritis (RA).

Methods

The study involved 17 patients with active RA in whom combination therapy was initiated with methotrexate, sulfasalazine, hydroxychloroquine, and low-dose oral prednisolone. Clinical disease activity was assessed at screening, at baseline and after 2, 4, 8 and 12 weeks of therapy. ¹⁸F-FDG PET/CT of all joints was performed at baseline and after 2 and 4 weeks of therapy.

Results

¹⁸F-FDG maximum standardized uptake values showed a reduction of 22?±?13 % in 76 % of patients from baseline to week 2 and a reduction of 29?±?13 % in 81 % of patients from baseline to week 4. The percentage decrease in ¹⁸F-FDG uptake from baseline to week 2 correlated with clinical outcome, as measured by the disease activity score (DAS-28) at week 12. In addition, changes in C-reactive protein levels and erythrocyte sedimentation rate were positively associated with changes shown by PET.

Conclusion

¹⁸F-FDG PET/CT findings after 2 and 4 weeks of triple combination oral DMARD therapy correlated with treatment efficacy and clinical outcome in patients with early RA. ¹⁸F-FDG PET/CT may help predict the therapeutic response to novel drug treatments.     

11C-Choline PET/CT in patients with hormone-resistant prostate cancer showing biochemical relapse after radical prostatectomy

Purpose

To determine the diagnostic efficacy of ¹¹C-choline PET/CT in patients with prostate cancer (PC) after radical prostatectomy who presented with increasing PSA levels during follow-up in spite of being on hormone treatment (HT), and therefore showing HT resistance.

Methods

We evaluated a large series of 157 consecutive PC patients previously treated by radical prostatectomy who presented with biochemical recurrence with increasing PSA levels in spite of ongoing HT (HT-resistant patients). At the time of ¹¹C-choline PET/CT, the mean value of trigger PSA level was 8.3 (range ?0.2 – 60.6 ng/mL), the mean PSA doubling time (PSAdt) was 5.3? (range ?0.4 – 35 months), and the mean PSA velocity (PSAvel) was 22.1 ng/mL/year (range 0.12 – 82 ng/mL/year). ¹¹C-Choline PET/CT was performed following a standard procedure at our centre to investigate increasing PSA levels, either as the first imaging procedure or in patients with negative conventional imaging. At the time of ¹¹C-choline PET/CT all patients were receiving HT (61 were receiving monotherapy and 96 multidrug therapy). PET-positive findings were validated by: (a) transrectal US-guided biopsy in patients with recurrence in the prostatic bed, (b) surgical pelvic lymphadenectomy, (c) other imaging modalities, including repeated ¹¹C-choline PET/CT, performed during a minimum follow-up of 12-months.

Results

¹¹C-Choline PET/CT showed positive findings in 104 of the 157 patients (66 %). ¹¹C-choline PET/CT detected: a single lesion in 40 patients (7 in the prostate bed, 10 in lymph nodes, 22 in bone, 1 at another site); two lesions in 18 patients (7 in lymph nodes, 7 in bone, 4 in both lymph nodes and bone); three or four lesions in 7 patients (4 in lymph nodes, 2 in bone, 1 at another site); and more than four lesions in the remaining 39 patients (2 in the prostate bed, 12 in lymph nodes, 12 in bone, 11 in both lymph nodes and bone, 2 at other sites). In ¹¹C-choline PET-negative patients, the mean values of trigger PSA, PSAdt and PSAvel were 3.8 ng/mL (range 0.2 – 11.9 ng/mL) 7.0 months (range 1.21 – 35 months) and 5.8 ng/mL/year (range 0.12 – 30.1) respectively, while in ¹¹C-Choline-PET-positive patients they were 10.5 ng/mL (range 0.2 – 60.6), 4.4 months (range 0.4 – 19.7) and 15.9 ng/mL/year (range 0.5 – 82.0) respectively. The differences between PET-negative and PET-positive patients were statistically significant for all these parameters: trigger PSA, p?<?0.01; PSAdt, p?<?0.01; PSAvel, p?=?0.03.

Conclusion

In our patient population, ¹¹C-choline PET/CT was able to detect relapsed disease in a large proportion of HT-resistant PC patients during HT. These data, obtained in a large series, suggest that HT withdrawal before performing a ¹¹C-choline PET/CT scan may not be necessary for the detection of recurrent disease if PSA levels are increasing and PSA kinetics are rapid.     

Prospective evaluation of 68Ga-DOTANOC PET-CT in differentiated thyroid cancer patients with raised thyroglobulin and negative 131I-whole body scan: comparison with 18F-FDG PET-CT

Purpose

The purpose of the study was to evaluate the role of ⁶⁸Ga-DOTANOC PET-CT in differentiated thyroid cancer (DTC) patients with negative ¹³¹I-whole body scan (WBS) along with serially increasing serum thyroglobulin (Tg), and compare the same with ¹⁸F-FDG PET-CT.

Methods

Sixty two DTC patients with serially rising Tg levels and negative ¹³¹I-WBS were prospectively enrolled. All patients underwent ⁶⁸Ga-DOTANOC PET-CT and ¹⁸F-FDG PET-CT within an interval of two weeks. PET-CT analysis was done on a per-patient basis, location wise and lesion wise. All PET-CT lesions were divided into four categories-local, nodal, pulmonary and skeletal. Histopathology and/or serial serum Tg level, clinical and imaging follow up (minimum-1 year) were used as a reference standard.

Results

Ga-DOTANOC PET-CT demonstrated disease in 40/62 (65 %) patients and ¹⁸F-FDG PET-CT in 45/62 (72 %) patients, with no significant difference on McNemar analysis (p?=?0.226). Per-patient sensitivity and specificity of ⁶⁸Ga-DOTANOC PET-CT was 78.4 %, 100 %, and for ¹⁸F-FDG PET-CT was 86.3 %, 90.9 %, respectively. Out of 186 lesions detected by both PET-CTs, 121/186 (65 %) lesions were seen on ⁶⁸Ga-DOTANOC PET-CT and 168/186 (90.3 %) lesions on ¹⁸F-FDG PET-CT (p?<?0.0001). There were 103/186 (55 %) lesions concordant on both. Excellent agreement was noted between ⁶⁸Ga-DOTANOC PET-CT and ¹⁸F-FDG PET-CT for detection of local disease (??=?0.92), while moderate agreement was noted for nodal and pulmonary disease (??=?0.67). ⁶⁸Ga-DOTANOC PET-CT changed management in 21/62 (34 %) patients and ¹⁸F-FDG PET-CT in 17/62 (27 %) patients.

Conclusion

Ga-DOTANOC PET-CT is inferior to ¹⁸F-FDG PET-CT on lesion based but not on patient based analysis for detection of recurrent/residual disease in DTC patients with negative WBS scan and elevated serum Tg levels. It can also help in selection of potential candidates for peptide receptor radionuclide therapy.     

Detection of neck recurrence in patients with differentiated thyroid cancer: comparison of ultrasound, contrast-enhanced CT and 18F-FDG PET/CT using surgical pathology as a reference standard: (ultrasound vs. CT vs. 18F-FDG PET/CT in recurrent thyroid cancer)

Objectives

To compare the diagnostic performance of ultrasound, contrast-enhanced computed tomography (CT) and ¹⁸F-FDG positron emission tomography (PET)/CT for detecting recurrent differentiated thyroid cancer in the neck.

Methods

Twenty patients who had undergone previous surgery for differentiated thyroid cancer (19 papillary carcinomas; 1 medullary carcinoma) and presented with pathologically proven recurrence in the neck were included. All patients had undergone ultrasound, CT and PET/CT in the 2 months before further surgery. In each patient, ultrasound, CT and PET/CT images were retrospectively reviewed to determine the presence of loco-regional recurrence by level-by-level analysis. Imaging results were correlated with the histological evaluation of the neck dissection as a standard of reference.

Results

Recurrences were found at 52 out of 110 cervical nodal levels surgically explored. The sensitivity, specificity and accuracy were 69.2 %, 89.7 % and 80.0 % for ultrasound; 63.5 %, 94.8 % and 80.0 % for CT; and 53.8 %, 79.3 % and 67.3 % for PET/CT, respectively. ROC analysis revealed higher diagnostic performance with ultrasound than with PET/CT for detecting recurrent tumour.

Conclusions

Although no significant difference was found among the three techniques, the sensitivity and specificity of ultrasound and CT were higher than those of PET/CT for the evaluation of cervical recurrence in patients with differentiated thyroid cancer.

Key Points

? Ultrasound, CT and ¹⁸ F-FDG PET/CT can all detect recurrent thyroid cancer. ? Ultrasound and CT have higher sensitivity and specificity. ? Ultrasound, CT and ¹⁸ F-FDG PET/CT frequently demonstrated discordant findings     

11C-Choline PET/CT detects the site of relapse in the majority of prostate cancer patients showing biochemical recurrence after EBRT

Purpose

The aim of this retrospective study was to evaluate the usefulness and the detection rate of ¹¹C-choline PET/CT in a population of patients with prostate cancer (PC), exclusively treated with external beam radiotherapy (EBRT) as primary treatment, who showed biochemical relapse.

Materials and methods

We enrolled 140 patients showing a serum PSA level >2 ng/mL (mean 8.6 ng/mL, median 5 ng/mL, range 2 – 60 ng/mL). All patients had been treated with EBRT to the prostate gland and prostatic fossa with doses ranging from 70 to 76 Gy in low-risk patients (T1/T2 and/or serum PSA <10 ng/mL) and escalating to >76 Gy (range 76 – 81 Gy) in high-risk patients (T3/T4 and/or serum PSA >10 ng/mL). Of the 140 patients, 53 were receiving androgen deprivation therapy at the time of the scan. All positive ¹¹C-choline PET/CT findings were validated by transrectal ultrasound-guided biopsy or at least 12 months of follow-up with contrast-enhanced CT, MR, bone scintigraphy or a repeated ¹¹C-choline PET/CT scan. The relationships between the detection rate of ¹¹C-choline PET/CT and the factors PSA level, PSA kinetics, Gleason score, age, time to relapse and SUVmax in patients with positive findings were analysed.

Results

¹¹C-Choline PET/CT detected the site of relapse in 123 of the 140 patients with a detection rate of 87.8 % (46 patients showed local relapse, 31 showed local and distant relapse, and 46 showed only distant relapse). In patients with relapse the mean serum PSA level was 9.08 ng/mL (median 5.1 ng/mL, range 2 – 60 ng/mL), the mean PSA doubling time was 5.6 months (median 3.5 months, range 0.4 – 48 months), and the mean PSA velocity was 15 ng/mL/year (median 8.8 ng/mL/year, range 0.4 – 87 ng/mL/year). Of the 123 patients with relapse, 77 (62.6 %) showed distant relapse with/without local relapse, and of these 77, 31 (40.2 %) showed oligometastatic disease (one or two distant lesions: lymph node lesions only in 16, bone lesions only in 14, and lymph node lesions and bone lesions in 1). In univariate and multivariate analyses PSA kinetics was the only variable affecting ¹¹C-choline PET/CT detection rate. A significant correlation between PSA kinetics and site of recurrence (local relapse only vs. distant metastasis) was also observed.

Conclusion

The detection rate of ¹¹C-choline PET/CT in patients with PC showing biochemical recurrence after EBRT as primary treatment is relatively high (87.8 %). ¹¹C-Choline PET/CT was able to detect extraprostatic disease in the 62.6 % of patients. Considering this high detection rate, ¹¹C-choline PET/CT could have clinical usefulness in the management of these PC patients, but this should be confirmed in future studies.