Value of SPET/CT image fusion in the assessment of neuroendocrine tumours with 111In-Pentetreotide scintigraphy

Comparison of the detecting capability between 123I-mIBG and post-therapeutic 131I-mIBG scintigraphy for curie scoring in patients with neuroblastoma after chemotherapy

OBJECTIVE

To evaluate the detecting capability between planar imaging (PI) and PI combined with single-photon emission computed tomography/computed tomography (PICWS), including ¹²³I- and ¹³¹I-labeled metaiodobenzylguanidine (mIBG) and to compare the detecting capability between ¹²³I-mIBG and post-therapeutic ¹³¹I-mIBG scintigraphy including PI and PICWS for Curie scoring in patients with neuroblastoma.

METHODS

Sixty-two patients with 66 pairs of complete images with neuroblastoma were enrolled in this retrospective study.

RESULTS

Comparing the Curie scoring between ¹²³I-mIBG PI and PICWS and between post-therapeutic ¹³¹I-mIBG PI and PICWS, findings were concordantly negative in 28.79% and 18.18% of studies, concordantly positive in 66.67% and 74.24% of studies, and discordant in 4.54% and 7.58% of studies, respectively. PICWS was superior to PI including ¹²³I- and ¹³¹I-mIBG in the evaluation of Curie scoring for neuroblastoma patients (both P < 0.001). Comparing the Curie scores between ¹²³I- and post-therapeutic ¹³¹I-mIBG PI and between ¹²³I- and post-therapeutic ¹³¹I-mIBG PICWS, concordantly negative imaging was visualized in 22.73% and 19.70% of studies, concordantly positive imaging in 66.67% and 69.70% of studies, and discordant imaging in 10.60% and 10.60% of studies, respectively. Post-therapeutic ¹³¹I-mIBG was significantly better than that of ¹²³I-mIBG scintigraphy including PI and PICWS in detecting the Curie scoring for neuroblastoma patients (both P < 0.001).

CONCLUSION

The present study demonstrates that ¹³¹I- or ¹²³I-mIBG PICWS are more helpful in the evaluation of Curie scores than that of conventional PI and that post-therapeutic ¹³¹I-mIBG is superior to ¹²³I-mIBG scintigraphy for the detecting capability of Curie scoring in patients with neuroblastoma.

Contribution of ¹¹¹In-pentetreotide SPECT/CT imaging to conventional somatostatin receptor scintigraphy in the detection of neuroendocrine tumours

AIM

The aim of the study was to assess the contribution of 111In-pentetreotide single-photon emission computed tomography/computed tomography (SPECT/CT) imaging to conventional somatostatin receptor scintigraphy (SRS) in terms of lesion characterization and localization in the detection of neuroendocrine tumours (NETs).

MATERIALS AND METHODS

A total of 107 patients with suspected or confirmed NET underwent SRS and SPECT/CT after the injection of 148-222 MBq of 111In-pentetreotide. SRS and SPECT/CT images were interpreted independently. Each site of abnormal tracer uptake was recorded according to the anatomical localization, and as being consistent or not with NET. The findings were confirmed with pathological and/or clinical/imaging follow-up data.

RESULTS

A final diagnosis of NET was achieved in 49/107 patients (45.8%). No evidence of NET was found in the rest. SPECT/CT resulted in a significant reduction of indeterminate cases [14/107 (13.1%) vs. 1/107 (0.9%); P<0.001] and correctly reclassified one patient as negative for NET and another as positive for NET. SPECT/CT had 87.8% sensitivity and 96.6% specificity on a patient-based analysis, statistically higher than SRS (P<0.001). A total of 160 foci were detected (108 NETs and 52 physiological/benign tumours). SRS correctly classified 105/160 foci (65.6%) and remained inaccurate for 55 lesions. These 55 included 31 indeterminate lesions, 12 lesions detected only by SPECT/CT and 12 false-positive lesions. The number of foci correctly classified on the SPECT/CT images was 151/160 (94.4%), whereas two remained indeterminate and seven were false-positive findings.

CONCLUSION

SPECT/CT provides incremental diagnostic value over SRS, mainly because of a precise anatomical localization that helps discriminate between tumour lesions and physiological uptake. SPECT/CT may detect unsuspected lesions in a small proportion of patients.

Comparison of diagnostic value of I-123 MIBG and high-dose I-131 MIBG scintigraphy including incremental value of SPECT/CT over planar image in patients with malignant pheochromocytoma/paraganglioma and neuroblastoma

PURPOSE

to compare lesion detectability of I-123 MIBG scintigraphy with that of high-dose I-131 MIBG and to evaluate incremental benefit of SPECT/CT over planar image for the detection and localization of the lesions in patients with I-131 MIBG therapy for malignant pheochromocytoma/paraganglioma and neuroblastoma.

MATERIALS AND METHODS

we retrospectively investigated 16 patients with malignant pheochromocytoma/paraganglioma and neuroblastoma, who were referred for I-131 MIBG therapy. We investigated the lesion detectability in 10 pairs of I-123 and high-dose I-131 MIBG studies of the same patient, obtained within 2 weeks. In 31 studies of I-123 MIBG scintigraphy in 16 patients and 17 studies of high-dose I-131 MIBG scintigraphy in 12 patients, we compared planar and SPECT/CT images for the lesion detectability and localization.

RESULTS

the number of lesions detected by I-123 MIBG planer image and SPECT/CT and high-dose planer I-131 MIBG and SPECT/CT were 3.0 and 3.7, 7.3 and 7.7 per study, respectively. SPECT/CT images provided additional diagnostic information over planar images in 25 studies (81%) of 12 patients (75%) in I-123 MIBG scintigraphy and in 9 studies (53%) of 9 patients (75%) in high-dose I-131 MIBG scintigraphy.

CONCLUSION

post-therapy high-dose I-131 MIBG scintigraphy is superior to I-123 MIBG scintigraphy in lesion detectability even in comparison with I-123 MIBG SPECT/CT images and high-dose I-131 MIBG planar images in patients with malignant neuroendocrine tumors. SPECT/CT images are helpful for accurate identification of anatomic localization compared with planar images.

Comparison of single time-point [111-In] pentetreotide SPECT/CT with dual time-point imaging of neuroendocrine tumors

PURPOSE

to determine whether single time-point single-photon emission computed tomography-computed tomography (SPECT/CT) somatostatin receptor imaging can replace traditional dual time-point planar and SPECT somatostatin receptor scintigraphy for evaluation of neuroendocrine tumors.

MATERIALS AND METHODS

twenty-four patients (9 males, 15 females; mean age: 56 years; range: 14-82 years) underwent [111-In] pentetreotide scintigraphy, with planar whole-body images acquired at 24 and 48 hours after injection and abdominal SPECT/CT at 24 hours postinjection. Two blinded readers independently interpreted each study, using single time-point (24 hours planar and SPECT/CT) and separately using dual time-point (24- and 48-hours planar, and 24-hour SPECT without CT) image information. Consensus interpretations were compared with surgical pathology, or clinical and radiologic follow-up for at least 12 months.

RESULTS

Interobserver agreement was excellent (κ = 0.86) for single time-point imaging, and good (κ = 0.56) with dual time-point imaging. After consensus review, single time-point imaging identified pathologic lesions in 11 of 12 subjects with diagnosis of NET at follow-up, and in 0 of 12 subjects without NET (sensitivity 92%; specificity 100%). Dual time-point imaging performed similarly, but missed an additional NET case (sensitivity 83%; specificity 100%). After review of SPECT/CT, the readers considered that additional 48 hours imaging was not necessary in the majority of cases, indicating high degree of confidence with the single time-point imaging.

CONCLUSION

[111-In] pentetreotide SPECT/CT imaging at 24 hours identifies pathologic disease sites and distinguishes physiologic activity equally well compared to traditional strategies using 2 imaging days. Routine use of SPECT/CT will allow single time-point imaging without loss of diagnostic accuracy, enhancing patient convenience, and clinical throughput.

[Radioguided surgery of intestinal carcinoid tumor relapse. Role of SPECT-CT]

We present a patient with clinical suspicion of intestinal carcinoid relapse confirmed by a somatostatin receptor scintigraphy. A very intense somatostatin avid abdominal lesion was located and radioguided surgery was proposed. Prior to the procedure, we performed a SPECT-CT that made it possible to detect and localize the lesion anatomically, thus facilitating the performance of the radioguided procedure. Furthermore, it modified the planning of the intervention with the adequate physical and human resources to prevent the possible surgical complications.

Incremental value of 111-in pentetreotide SPECT/CT fusion imaging of neuroendocrine tumors

RATIONALE AND OBJECTIVES

Hybrid single photon-emission computed tomographic (SPECT) and computed tomographic (CT) imaging for the investigation of neuroendocrine tumors allows the fusion of functional and anatomic information in a rapid and efficient method. The aim of this study was to assess the incremental diagnostic value of (111)In pentetreotide SPECT/CT imaging compared with traditional planar and SPECT imaging with respect to lesion localization and characterization and reader confidence.

MATERIALS AND METHODS

Forty-nine patients (23 male, 26 female; mean age, 56.9 years; range, 14-88 years) who underwent (111)In pentetreotide planar, SPECT, and SPECT/CT imaging were eligible for this retrospective study, including patients with suspected or confirmed carcinoid tumors (n = 24), endocrine pancreatic tumors (n = 18), medullary thyroid cancer (n = 3), paragangliomas (n = 2), and multiple endocrine neoplasia type I (n = 2). Planar and SPECT images were reviewed by two blinded readers, followed by interpretation using additional SPECT/CT images in a subsequent session. A third reader provided consensus in cases with disagreements.

RESULTS

In 55 of 89 lesions (61.8%), (111)In pentetreotide SPECT/CT imaging improved lesion localization compared to planar and SPECT imaging; in 25 of 89 lesions (28.1%), SPECT/CT imaging changed lesion classification. In 20 of 49 patients (40.8%) for reader 1 and 14 of 49 patients (28.6%) for reader 2, (111)In pentetreotide SPECT/CT imaging provided incremental diagnostic value, which was considered likely to affect patient management in twelve of 20 and seven of 14 patients, respectively. Increased reader confidence was found in 32 of 49 patients (65.3%) for both readers with uniformly high confidence after SPECT/CT interpretation.

CONCLUSIONS

Hybrid (111)In pentetreotide SPECT/CT imaging provides incremental diagnostic value and greater reader confidence over planar and SPECT imaging. This is achieved though superior lesion localization, the identification of physiologic activity, and additional anatomic information derived from the nondiagnostic CT portion of the study.

Anatomical accuracy of hybrid SPECT/spiral CT in the lower spine

AIM

The anatomical accuracy of hardware-based registration of skeletal single photon emission computed tomography (SPECT) and X-ray computerized tomography (CT) has as yet not been studied. The aim of this study was to evaluate this variable in the lower spine for a newly introduced hybrid SPECT/spiral-CT camera.

METHODS

In 22 patients referred for degenerative joint disease or tumours, whole-body bone scintigraphy including hybrid SPECT/spiral CT of the lower spine was performed. Subsequent analyses were performed on these pairs of images as well as on data sets obtained after using a rigid automated fusion procedure in addition. Two observers independently measured the distances between the visually determined centres of gravity of the CT and SPECT representation of the fourth and fifth lumbar vertebral body in the X-, Y- and Z-directions (X-, Y- and Z-distances).

RESULTS

The distances determined by the two observers for the two vertebral bodies correlated significantly and were averaged for further analysis. For hybrid SPECT/spiral CT without consecutive automated registration, the mean X-, Y- and Z-distances were 1.6+/-1.9 mm, 1.7+/-1.3 mm and 0.9+/-0.5 mm, respectively. Additional automated registration lowered these values to 1.2+/-0.9 mm, 1.1+/-0.7 mm and 0.8+/-0.4 mm, respectively. The difference for the Y-distance proved statistically significant (P<0.05). Additional automated registration significantly reduced the number of subjects in whom at least one of the distances determined was greater than the SPECT pixel size of 4.6 mm from 14% (n=3) to 0% (P<0.05).

CONCLUSION

Hardware-based fusion between skeletal SPECT and CT offers a nearly perfect data match in the lower spine. The additional use of a tool for automated rigid registration has the potential to reduce the error of alignment even further and may be useful in patients with reduced compliance leading to movements between the two examinations.