Jan Schiefer

Impact of Multiphase 68Ga-DOTATOC-PET/CT on therapy management in patients with neuroendocrine tumors.

Aim: Retrospective evaluation of the impact of integrated positron emission tomography/computed tomography (PET/CT) using 68Ga-DOTA(0)-Phe(1)-Tyr(3)-octreotide (68Ga-DOTATOC) on the therapeutic management of patients with neuroendocrine tumors (NET). Methods: The 68Ga-DOTATOC-PET/CT data of 66 patients (31 male, 35 female; age: 29–79, mean age: 56 years) with known or suspected NET were included. Imaging data (PET and triple-phase contrast-enhanced CT) were evaluated in consensus by two readers for the visualization of NET manifestations. Combined PET/CT, clinical and imaging follow-up as well as histopathology (if available) served as the reference standard. In order to assess the impact of the respective submodalities on the therapeutic strategy chosen, the results were compared to the treatment decision made by the interdisciplinary NET tumor board of our institution. Results: Two of the initial 66 patients included did not suffer from NET according to further immunohistopathological examination. In 50 of the remaining 64 (78%) NET patients, a total of 181 NET manifestations were detected by PET/CT. 59/181 (32.6%) were detected by one submodality only (CT 17.1%, PET 15.5%, p for comparison of both = 0.459). Combined PET/CT reading had an impact on the therapeutic management in 24 of 64 (38%) NET patients: primary resection (n = 5), curative lymph node resection (n = 1), initiation/switch of chemotherapy (CTx) due to progressive disease (n = 10), no surgery due to systemic disease (n = 2), radiopeptide receptor therapy instead of CTx (n = 1), additional bisphosphonate therapy (n = 4), and hepatic brachytherapy (n = 1). In 12 of 24 (50%) of these patients, relevant findings were detected by a single submodality only: CT (n = 5), PET (n = 7); p for comparison = 0.774). Conclusion:68Ga-DOTATOC-PET/CT influences therapeutic management in about one third of patients examined. CT and PET are comparably sensitive, deliver complementary information and equally contribute to therapeutic decision-making. Thus, despite the merits of the PET modality, the CT component must not be neglected and an optimized multiphase CT protocol is recommended.

68Ga-DOTATOC PET/CT of Neuroendocrine Tumors: Spotlight on the CT Phases of a Triple-Phase Protocol

The diagnostic value of neuroendocrine tumor (NET) imaging using PET with integrated CT is dependent on both components. This retrospective study assessed the value of the single CT phases of a triple-phase (early arterial, portal-venous inflow, and venous) CT protocol in comparison to 68Ga-DOTATOC PET in a masked reading. Methods: 68Ga-DOTATOC PET/CT examinations from 51 patients with known or suspected NET were included. Two readers assessed the data of PET and each of the 3 CT phases for NET lesions independently (using a 3-point score: 1 = benign, 2 = indeterminate, and 3 = malignant) and by consensus (using binary benign/malignant interpretation only). Only lesions within the field of the abdominal scan were evaluated. Clinical and imaging follow-up, histopathology (if available), and the decision of an interdisciplinary truth-panel served as a standard of reference. In addition to the calculation of standard statistical parameters (including general linear mixed models), interobserver reliability was estimated (Cohens κ). Results: Of 510 abdominal lesions observed, 354 were classified as malignant. Sensitivity was 77.1% for combined triple-phase CT, 53.4% for arterial CT, 66.1% for portal-venous CT, 66.9% for venous CT, and 72.8% for PET. The respective specificities were 85.3%, 92.9%, 92.3%, 89.7%, and 97.4%, and the respective accuracies were 79.6%, 65.5%, 74.1%, 73.9%, and 80.4%. Although arterial CT was found to be inferior to PET, portal-venous CT, and venous CT (P < 0.001), the differences between the other scans were not significant. Detection was exclusively by PET for 16.1% of lesions, by triple-phase CT for 20.3%, by arterial CT for 0.5%, by portal-venous CT for 3.9%, and by venous CT for 3.9%. Regarding interobserver reliability, the κ-value was 0.768 for PET, 0.391 for triple-phase CT, 0.577 for arterial CT, 0.583 for portal-venous CT, and 0.482 for venous CT. Conclusion: No CT phase can be omitted in NET imaging, and the triple-phase protocol continues to be strongly recommended also for PET/CT.

Evaluation of interim PET response criteria in paediatric Hodgkin's lymphoma—results for dedicated assessment criteria in a blinded dual-centre read

BACKGROUNDnThe aim of this study was to evaluate the use and reliability of the new positron emission tomography (PET)-based response criteria for interim positron emission tomography (iPET) in patients with paediatric Hodgkins lymphoma (pHL). Particular emphasis was put on interobserver variability and on identification of a visual cut-off defining patients with very low risk for relapse.nnnPATIENTS AND METHODSnThe iPET scans of 39 pHL patients were evaluated in two independent centres by two PET-experienced specialists in nuclear medicine (blinded read, centre consensus) each. The iPET scans were interpreted using a 5-point scale and were compared with the outcome. Cohens kappa-test (κ) was used to analyse the interobserver agreement.nnnRESULTSnConcordant ratings were assessed in 19 patients with iPET-negative findings, in 11 patients with iPET-positive findings and in 2 patients with inconclusive ratings. A substantial agreement between attended centres was achieved (κ = 0.748). All patients suffering relapse were concordantly identified, taking mediastinal blood pool structures (MBPS) as visual cut-off between PET-positive and PET-negative findings, respectively. All pHL patients with uptake lower than or equal to MBPS remained in complete remission.nnnCONCLUSION(S)nThe iPET interpretation assured low interobserver variability. High sensitivity for identification of pHL patients suffering relapse is achieved if [18F]-fluorodeoxyglucose uptake above the MBPS value is rated as a PET-positive finding.

Quantification in 68Ga-DOTA(0)-Phe(1)-Tyr(3)-Octreotide Positron Emission Tomography/Computed Tomography: Can We Be Impartial about Partial Volume Effects?

Aim: In combined positron emission tomography/computed tomography (PET/CT) of neuroendocrine neoplasms using 68Ga-DOTA(0)-Phe(1)-Tyr(3)-octreotide (68Ga-DOTATOC), partial volume effects (PVEs) may occur in smaller lesions. This study determined the lesional cutoff size for the occurrence of PVEs in a clinical setting. Methods: Retrospective assessment of 51 PET/CT examinations (16-slice PET/CT device) for malignant PET foci was carried out. In all foci, the maximal standardized uptake value (SUVmax) and maximal lesion diameter on axial CT was documented. Determined SUVmax and lesional sizes were correlated via LOESS regression. In the resulting curve, the cutoff point for SUVmax size dependency was determined visually and mathematically using 2 approximating straight lines. Results: In 45 patients, 313 of 413 PET foci found were malignant, measurable on CT and had a roughly spherical geometry (SUVmax: 2.5-103.3, mean ± SD 20.5 ± 15.18; CT diameter: 5-103 mm, mean ± SD 21.8 ± 13.1 mm). The cutoff lesional size for the occurrence of PVEs was 20.4 mm by the mathematical approach and 25 mm by visual assessment. Conclusion: In 68Ga-DOTATOC imaging, the clinical lesional size threshold is far larger than expected from systemic resolution only. Thus, tracer uptake quantification is only acceptable in sufficiently large lesions.

Renal Sympathetic Denervation by CT-Guided Ethanol Injection: A Phase II Pilot Trial of a Novel Technique.

AbstractObjectivesCT-guided ethanol-mediated renal sympathetic denervation in treatment of therapy-resistant hypertension was performed to assess patient safety and collect preliminary data on treatment efficacy.nMaterials and MethodsEleven patients with therapy-resistant hypertension (blood pressure of >160xa0mmHg despite three different antihypertensive drugs including a diuretic) and following screening for secondary causes were enrolled in a phase II single arm open label pilot trial of CT-guided neurolysis of sympathetic renal innervation. Primary endpoint was safety, and secondary endpoint was a decrease of the mean office as well as 24-h systolic blood pressure in follow-up. Follow-up visits at 4xa0weeks, 3, and 6xa0months included 24-h blood pressure assessments, office blood pressure, laboratory values, as well as full clinical and quality of life assessments.ResultsNo toxicities ≥3° occurred. Three patients exhibited worsened kidney function in follow-up analyses. When accounting all patients, office systolic blood pressure decreased significantly at all follow-up visits (maximal mean decrease −41.2xa0mmHg at 3xa0months). The mean 24-h systolic blood pressure values decreased significantly at 3xa0months, but not at 6xa0months (mean: −9.7 and −6.3xa0mmHg, respectively). Exclusion of five patients who had failed catheter-based endovascular denervation and/or were incompliant for antihypertensive drug intake revealed a more pronounced decrease of 24-h systolic blood pressure (mean: −18.3 and −15.2xa0mmHg at 3 and 6xa0months, pxa0=xa00.03 and 0.06).ConclusionCT-guided sympathetic denervation proved to be safe and applicable under various anatomical conditions with more renal arteries and such of small diameter.

Position-related renal perfusion disturbances as a possible underestimated mechanism in patients with resistant hypertension: a case vignette

PurposeIn patients with resistant hypertension and large blood pressure fluctuations, the role of orthostatic hypertension, associated with position-dependent renal perfusion disturbances, has not been investigated in detail yet.MethodsIn this regard, four patients from our outpatient clinic were investigated by the use of 24-h ambulatory blood pressure monitoring (ABPM), active standing test, renal duplex sonography and Tc99m-mercaptoacetyltriglycine [MAG3] renal scintigraphy in supine and upright position.ResultsFour patients (three males and one female; 51–79xa0years) with a mean of 4.25 antihypertensive drugs including a diuretic were evaluated. The recorded blood pressure fluctuations were up to 89/58–198/121xa0mmHg. Three patients exhibited an extreme and one a normal dipping pattern in the 24-h ABPM. Three patients demonstrated a hypertensive orthostatic reaction in the active standing test. By duplex sonography, a bilateral decrease in the overall intrarenal resistive indices was shown in two patients, a unilateral overall decrease in one patient and a localized decrease in the last patient. From a morphological standpoint of view, all patients had a normal anatomical position and a physiologic descent of both kidneys. But the normalized tubular extraction rate was pathologic in all patients in the upright body position and normalized when lying down in three patients.ConclusionsPosition-dependent renal perfusion should be considered in patients with large blood pressure fluctuations and extreme dipping. If morphological imaging shows no abnormalities, functional imaging provides additional information. Further investigation is needed, foremost if nephropexy could improve blood pressure control in some of these patients.

Contents Vol. 97

D.H. Abbott, Madison, Wisc. E. Arzt, Buenos Aires A.V. Babwah, London, Ont. T. Bartness, Atlanta, Ga. C.L. Bethea, Beaverton, Oreg. D.W. Brann, Augusta, Ga. B. Canny, Monash, Vic. M. Caplin, London K. Catt, Bethesda, Md. A. Chodobski, Providence, R.I. S.L. Dickson, Gothenburg J. Drouin, Montreal, Que. P.J. Enriori, Monash, Vic. W. Farrell, Keele M. Freeman, Tallahasse, Fla. A.C. Gore, Austin, Tex. K. Grove, Beaverton, Oreg. T. Harmar, Edinburgh A. Herbison, Dunedin J. Herman, Cincinnati, Ohio J.J. Hirst, Callaghan, N.S.W. T. Hökfelt, Stockholm U. Kaiser, Boston, Mass. K. Kim, Seoul J.Z. Kiss, Geneva A.C. Latronico, São Paulo G. Leng, Edinburgh J. Levine, Evanston, Ill. C. Libertun, Buenos Aires C. Llorens-Cortes, Paris A. Lomniczi, Beaverton, Oreg. A. Loudon, Manchester Z.-L. Lu, Edinburgh G. Martinez de la Escalera, Querétaro R. Melcangi, Milano I. Modlin, New Haven, Conn. Z. Naor, Tel Aviv M. Palkovits, Budapest I. Parhar, Kuala Lumpur D.W. Pfaff, New York, N.Y. T.M. Plant, Pittsburgh, Pa. J. Reul, Bristol R. Reynolds, Edinburgh E. Rissman, Charlottesville, Va. J.L. Roberts, San Antonio, Tex. I. Robinson, London P. Ruszniewski, Clichy W. Schlegel, Geneva D. Skinner, Laramie, Wyo. M. Sleeman, Clayton, Vic. J. Smith, Perth, W.A. E. Spinedi, La Plata R. Steiner, Seattle, Wash. E. Terasawa, Madison, Wisc. A. Tilbrook, Roseworthy, S.A. E. Wagner, Pomona, Calif. B. Walker, Edinburgh H. Watanobe, Chiba M. Watt, Clayton, Vic. M. Wierman, Denver, Colo. J. Wingfield, Seattle, Wash. S. Wray, Bethesda, Md. International Journal for Basic and Clinical Studies on Neuroendocrine Relationships