Vesical Imaging-Reporting and Data System (VI-RADS®): Initial experience in the classification of muscle-invasive bladder cancer

OBJECTIVE

to analyze the diagnostic accuracy of the VI-RADS® system in the differentiation of non-muscle-invasive bladder tumors (NMIBT from muscle-invasive bladder tumors (MIBT in suspicious cystoscopic findings without prior transurethral resection (TUR evaluated by radiologists with no prior experience in its use.

MATERIAL AND METHODS

retrospective study carried out with 18 patients with suspicious lesions in cystoscopy. All of them underwent MRI of the bladder. Two radiologists with no prior experience in the use of the VI-RADS® system evaluated the results. All patients underwent TUR of the suspicious lesions after MRI. The sensitivity and specificity of the system were analyzed for VI-RADS® values ≥ 3 or VI-RADS® ≥ 4, as well as the Cohen's kappa coefficient between both radiologists.

RESULTS

the mean values of sensitivity and specificity of both radiologists considering both the VI-RADS® ≥ 3 or VI-RADS® ≥ 4 values were 91.7% and 87.5%, respectively. The kappa coefficient considering the VI-RADS® ≥ 3 as positive, was 0.551 (P<.05), while considering the VI-RADS® ≥ 4 as positive, it was 0.571 (P<.05).

CONCLUSION

The VI--RADS® system presents excellent sensitivity (91.7% and specificity (87.5% values in the classification of MIBT performed by radiologists with no prior experience in its use, with a moderate interobserver agreement.

Diagnostic value of CT, PET and combined PET/CT performed with low-dose unenhanced CT and full-dose enhanced CT in the initial staging of lymphoma

AIM

The aim of this paper was to compare the accuracy of contrast-enhanced computed tomography (CT), positron emission tomography (PET), unenhanced low-dose PET/CT (LD-PET/CT) and full-dose enhanced PET/CT (FD-PET/CT) for the initial staging of lymphoma.

METHODS

One hundred and one lymphoma patients were examined by [18F]FDG-PET/CT including unenhanced low-dose CT and enhanced full-dose CT. Each modality of PET/CT was evaluated by a nuclear medicine physician and a radiologist unaware of the other modality, while the CT and PET images were interpreted separately by another independent radiologist and nuclear medicine physician respectively. The nodal and extranodal lesions detected by each technique were compared with a reference standard.

RESULTS

For nodal assessment, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (LR+), and negative LR (LR-) of LD-PET/CT were 97%, 96%, 98%, 95%, 26 and 0.02 respectively, and those of FD-PET/CT were 97%, 97%, 98%, 95%, 36 and 0.02. These results were significantly better than those of PET (sensitivity 82%, specificity 81%, PPV 88%, NPV 72%, LR+ 4.3, LR- 0.21). Likewise, both PET/CT displayed a higher sensitivity, NPV and LR- than CT (91%, 84%, 0.1 respectively). For organ evaluation, both modalities of PET/CT also had significantly better sensitivity and NPV than that of PET (LD-PET/CT: sensitivity 92%, NPV 90%; FD-PET/CT sensitivity 94%, NPV 92%; PET: sensitivity 70%, NPV 69%). The sensitivity, specificity, PPV and NPV for bone marrow involvement were 29%, 84%, 45% and 72% respectively for PET, and 29%, 90%, 56%, and 74% for both, LD-PET/CT, and FD-PET/CT. No significant differences were found between LD-PET/CT and FD-PET/CT, but FD-PET/CT detected important incidental findings in 5.9% of patients.

CONCLUSION

PET/CT is an accurate technique for the initial staging of lymphomas without significant differences between LD-PET/CT and FD-PET/CT. FD-PET/CT detects relevant incidental findings that are missed on LD-PET/CT.

[Integrated PET/CT scanner in oncology applications: a radiologic perspective]

OBJECTIVE

To describe our experience with an integrated PET/CT system in the clinical applications in Oncology.

MATERIAL AND METHODS

An integrated PET/CT scanner is an in-line system combining a full-ring detector PET and a multidetector row helical CT in one machine. This is a multidisciplinary technique involving a nuclear medicine physician, a radiologist, a radiopharmacologist, and a physicist, with distinct tasks and working together. The clinical indications for PET scans are determined by the National Health System, which in Madrid is coordinated by Agencia Laín Entralgo, and are performed by a nuclear medicine physician with the help of a radiologist for CT interpretation. The combined PET/CT scans are supervised and interpreted by both a nuclear medicine physician and a radiologist.

RESULTS

Between September 2003 and August 2005, a total of 2459 examinations were performed at our institution: 2200 were PET scans with low-dose noncontrast-CT for attenuation correction (clinical indications approved by NHS), and 259 were combined PET/CT scans with full-diagnostic enhanced-CT (in the setting of research programmes). The overall distribution of clinical indications for the 2459 examinations were: lung cancer 14.7%, solitary lung nodule characterization 7%, lymphoma 23.5%, colon cancer 18.5%, gastric cancer 1.9%, brain tumors 2.6%, head-neck tumors 5.5%, thyroid cancer 5%, breast cancer 4%, unknown origin cancer 4.3%, epilepsy 1.4%, others 11.6%.

CONCLUSION

In our experience, the integrated PET/CT system has advantages over the stand-alone PET and/or CT. However, more studies, as the ongoing research programmes at our facility are needed for the diagnostic validation of this technique.