Apport de la TEMP–TDM en complément de la scintigraphie osseuse planaire dans la pratique courante du service de médecine nucléaire de Nancy

ObjectiveThe purpose of our study was to evaluate the diagnostic performance of SPECT coupled to computed axial tomography (SPECT–CT) in our daily practice of bone scintigraphy.Subjects and methodsSPECT–CT obtained as a complement to the planar bone scintigraphy in 39 patients were studied. Each type of image was retrospectively read by two differents observers: a nuclear medicine physician who was unaware of SPECT–CT results analysed planar bone scintigraphy, a second one who was unaware of planar bone scintigraphy results analysed SPECT–CT images. In this population of patients, 17 patients were addressed in an oncologic setting. The 22 other patients were addressed for pain of indeterminate origin without neoplasic context.ResultsIn 13% of the cases, SPECT–CT specified the precise location of increased uptake foci seen on planar bone scintigraphy. In 38% of cases, SPECT–CT confirmed a diagnosis suspected by the planar bone scintigraphy. In 10% of cases, SPECT–CT established a diagnosis that was uncertain with planar bone scintigraphy. In 26% of cases, SPECT–CT brought no additional information. Finally in 3% of cases, SPECT–CT proved to be more sensitive than planar images.ConclusionOur study demonstrates the utility of SPECT–CT in the daily practice of bone scintigraphy, this complementary imaging study benefited to 74% of our patients.     

Apport de l’imagerie hybride TEMP-TDM dans le suivi d’un cancer différencié de la thyroïde

In the management of patients with differentiated thyroid cancer (DTC), abnormalities detected on planar whole body scan and ¹³¹I-SPECT are difficult to interpret because of a lack of anatomical landmarks and limited specificity. Integrated ¹³¹I-SPECT-CT imaging has an additional value for characterization of equivocal tracer uptake seen on planar imaging as well as for precise localization. We illustrate through an observation the incremental diagnostic value of ¹³¹I-SPECT-CT images in the diagnosis of a cervical lymph node mimicking a physiological uptake on planar views. A 35-year-old Tunisian female was followed for papillary thyroid carcinoma, for which she underwent total thyroidectomy and iratherapy. Three years after a complete remission, the thyroglobulin (Tg) level on TSH stimulation increased. Diagnostic planar images with ¹³¹I did not disclose any obvious pathological foci. Furthermore, we noticed an increased ¹³¹I-uptake in the left sub-mandibulary area, which suggested a salivary physiological activity. SPECT-CT of the neck and chest were then performed with a Symbia T camera. Fused images demonstrate that this activity corresponds to a cervical lymph node closely adjacent to sub-mandibulary gland. Management of the patient was then changed. In selected patients with DTC, hybrid imaging should be used as a complementary to planar imaging in terms of diagnostic accuracy, because of superior focus localization and additional anatomic information derived from the CT component. Integrated SPECT-CT is then a useful tool, especially in cases of unclear diagnoses, precising anatomical localization of areas of increased ¹³¹I-uptake and distinguishing malignant lesions from normal physiological uptakes. This is particularly important in an oncologic center, as ours, where we don’t yet have a positron emission tomography (PET) camera is not yet available.     

Intérêt de l’imagerie hybride TEMP-TDM pour la détection du ganglion sentinelle dans les cancers du sein

IntroductionSingle-Photon Emission Computed Tomography-Computed Tomography (SPECT-CT) is an hybrid technique which associates functional and morphological images. The aim of this study was to assess the role of SPECT-CT lymphoscintigraphy in sentinel node identification in patients with breast cancer.MethodsTwelve months prospective study was undertaken. Lymphoscintigraphy comprising planar and SPECT-CT acquisition was performed in 51 consecutive patients with breast cancer (mean age: 62 ± 11.3, range: 33–83 years). Planar and SPECT-CT images were interpreted separately and the two imaging techniques were compared with respect to their ability to identify sentinel node.ResultsAn add-value of SPECT-CT images was evidenced in 31% of cases: a more accurate anatomic localization in 21% of cases and identification of undeterminate sites of uptake in 10% of cases. Furthermore, SPECT-CT detected intramammary (4% of cases) and retromammary (2% of cases) sentinel nodes missed by planar imaging. SPECT-CT was more sensitive for internal mammary drainage detection (6% of cases). The added value proved higher in obese patients. Finally, functional and anatomical images fusion and three-dimensional overview provided clear and readily usable informations to the surgeon.ConclusionHybrid SPECT-CT imaging improves the preoperative localisation of sentinel nodes in patients with breast cancer, in particular in obese patients. SPECT-CT provides readily usable informations to the surgeon.     

Le ganglion sentinelle dans les cancers de la cavité orale : impact clinique et apport de l’imagerie hybride

ObjectivesWe report a prospective evaluation of the sentinel lymph node identification and biopsy in oral cavity cancer in order to assess the additional value of the single photon emission computed tomography-computed tomography (SPECT-CT).Patients and methodsThirteen patients with T1 or T2 clinical N0 oral cavity cancer were prospectively included. They first underwent a lymphoscintigraphy with planar imaging. A SPECT-CT was performed secondly. Finally, excised sentinel lymph nodes were screened according to a specific histological processing.ResultsThe scintigraphic detection rate was 100%, both with planar and SPECT/CT imaging. Dynamic and early images were predictive of the lymph node drainage territory for 11 patients (85%). An impact of SPECT/CT in 83% of cases was achieved with additional quantitative information in 58% cases and qualitative information in 58% cases. A greater sensibility was also pointed out for level 1 sentinel lymph nodes, close to the injection site. Once, an occult metastasis was revealed by the histological analysis of the sentinel lymph nodes.ConclusionRadioisotopic sentinel lymph node technique for oral cavity cancers allowed determining neck node status for all patients. Ninety-two percent of them were spared from a radical neck dissection or radiotherapy. Preoperative detection of sentinel lymph node is optimised in most cases by hybrid imaging procedure. Anatomical data provided by hybrid imaging are useful for surgery.     

Diagnostic d’une fracture occulte isolée de la marge postérieure du tibia par la TEMP–TDM

We report the case of a 56-year-old woman, investigated for pains of the right ankle related to a traumatism of an unspecified mechanism. The radiographic assessment was negative. The ^99mTc-HDP 3-phase bone scintigraphy highlighted, on the blood pool and the delayed images, a located lesion on the right ankle. The single photon emission computerized tomography guided by computerized tomography (SPECT-CT) showed a focused uptake on the posterior margin of the right tibia and a sharp lucent line within the tomoscintigraphic spot of uptake. The diagnosis accepted was an isolated occult fracture of the posterior margin of the right tibia. The contribution of the ^99mTc-HDP 3-phase bone scintigraphy combined with the SPECT-CT in the diagnosis of the occult fractures is discussed.     

Imagerie hybride (TEMP/TDM,TEP/TDM) et cancer différencié de la thyroïde

Differentiated thyroid cancer (DTC) is generally associated with a good prognosis. Local recurrences, mainly lymph-node involvement, account for 15–20% of cases and are surgically treated. Distant metastases, mostly in lungs and more rarely in bones, are present in 5% of patients. When iodine uptake is sufficient (in approximately 60% of patients), distant metastases can be destroyed by iterative activities of iodine 131. Serum thyroglobulin (Tg), which can be assessed either on hormonal treatment or on TSH stimulation is considered as the tumour marker in DTC. Functional (iodine 131 scintigraphy, FDG PET, bone scintigraphy) or anatomical (neck ultrasound, thoracic CT, bone MRI) imaging methods can be performed when Tg increases in order to show residual/recurrent disease. In recent years, new hybrid equipments integrating both a gamma camera and CT scan (SPECT/CT) have been commercialized while positron emission tomography cameras associated with CT (PET/CT) have been installed on the whole French territory. These equipments, which allow us to directly correlate functional and anatomical images, greatly improve the interpretation of planar scintigraphy or that of PET alone. Hybrid imaging enables us to precisely localize scintigraphic foci and most often, to immediately verify whether they correspond to tumour lesions. The aim of this article is to review the role of SPECT/CT and PET/CT in the management of patients with DTC in 2010.     

Synostose talo-calcanéenne et scintigraphie osseuse à l’HMDP-Tc : intérêt des images TEMP-TDM et problèmes de diagnostic différentiel

The purpose of this case report is to illustrate the scintigraphic aspect of a common foot disease, the tarsal synostosis. We report the clinical case of a 36 years old patient with a history of repeated injuries of left ankle, and experiencing residual pain. Foot radiographs and CT scan were not contributory and a MRI exam of the foot disclosed fibrous talocalcaneal bridge in favor of a syndesmosis. Bone scintigraphy with SPECT-CT images had a double interest, showing the active inflammatory process of the synostosis and delimiting the anatomical structures related to this uptake. Medical treatment with anti-inflammatory drugs has been introduced, associated to immobilization, and followed by sessions of physiotherapy.     

Intérêt de la TEMP-TDM dans le repérage des métastases chez les patients suivis pour cancer différencié de la thyroïde (À propos d’un cas)

It is very important in the management of patients with differentiated thyroid cancer (CDT) to precisely localize the foci of I-131 uptake, but it is difficult with planar scintigraphy only because of a lack of anatomic landmarks. In this context hybrid-imaging appears to be a preferred technique to overcome this deficiency. We report a case of metastatic follicular thyroid carcinoma (CDT) in which planar scintigraphy diagnosed multiples uptake abnormalities. The foci of I-131 pinpointed in abdominal cavity could not be identified anatomically on whole body scintigraphy. SPECT-CT imaging helped to locate these hot spots and assign them to hepatic localization.     

Intérêt de l’imagerie hybride TEMP/TDM pour la scintigraphie des récepteurs de la somatostatine dans le bilan des tumeurs endocrines gastro-entéro-pancréatiques

In this work, we have evaluated the potential of image fusion and attenuation correction (AC) of SPECT-CT imaging for the assessment of gastro-entero-pancreatic endocrine tumors by somatostatin receptor scintigraphy (SRS).MethodAfter optimisation of acquisition and reconstruction parameters, we have evaluated, in a prospective study, SRS performed over a period of one year. We have compared visual interpretations of planar and tomographic images versus SPECT/CT images to determine if anatomical localisation and diagnostic contributions are improved. In a semi-quantitative analysis of pathological foci, we have measured maximal intensity values (T_max), tumour to background ratios (T/B) and tumour contrasts (Ct) with and without AC.ResultsIn 25 SRS, visual analysis has shown anatomical localisation improvements in 60% of cases (CI95%, 39–79) and diagnostic improvements in 64% of cases (CI95%, 43–82). Doubtful foci proportion changed from 44 to 11%. In the semi-quantitative analysis of 41 pathological foci, Wilcoxon matched-pairs tests showed significantly higher T_max, T/B and Ct values after AC.ConclusionSPECT/CT imaging improves diagnostic quality of SRS thanks to a better foci localisation and a better lesional contrast in the image.     

Fréquence de la fixation physiologique de l’uncus pancréatique en scintigraphie à l’111In-pentétréotide : étude rétrospective chez 198 patients

AimThe aim of this study is to evaluate the frequency of physiological ¹¹¹In-DTPA-octreotide uptake in the pancreatic uncinate process, on SPECT-CT acquisitions.MethodsWe analysed retrospectively 247 patients ¹¹¹In-DTPA-octreotide SPECT-CT images realized in the nuclear medicine department of Haut-Lévêque hospital (CHU of Bordeaux, France) between June 2012 and March 2015. Intensity uptake of pancreas uncinate process was classified in comparison with physiological liver and spleen uptake. When positive, an uptake was considerated as physiologic when radiological investigations (CT, MRI or echoendoscopy) did not show anatomical lesion in the pancreatic head, or if no lesion appeared during clinical and radiological follow-ups.ResultsOne hundred and ninety-eight patients without uncus and cephalic pancreatic lesion were analysed. Forty-two percent had a physiological ¹¹¹In-DTPA-octreotide uptake in the pancreatic uncinate process. Uptake intensity was significant (greater than or equal to liver uptake) in 17%.ConclusionIntense physiological ¹¹¹In-DTPA-octreotide uptake of the pancreatic uncinate process can occur in 17% of cases on SPECT-CT acquisitions. This tracer accumulation can mimic malignancy in pancreatic head. Uptake in the pancreatic uncinate process should be correlated with morphologic examinations, such as CT, MRI or somatostatin PET-CT if available.     

Partie 2. Orthopedie – Traumatologie

Bone scintigraphy is a nuclear imaging scan using a radiopharmaceutical composed of a bisphosphonate coupled to a radionuclide (technetium 99 m). Radiopharmaceutical uptake is particularly important at the level of the bone structures having a strong osteoblastic activity. These uptakes can be due to a benign pathology (fracture, loosening of prosthesis, rheumatic pathologies, etc.) or to a malignant pathology (primary or secondary bone lesion). The high sensitivity of bone scintigraphy makes it particularly interesting at the initial stage of the pathology, especially when x-rays are normal. In addition, its specificity has clearly improved in recent years with the increasingly use of tomoscintigraphy coupled with X-ray scanning (SPECT/CT). We describe the operating principle of bone scintigraphy, normal uptakes with its variants as well as pathological uptake features in traumatic, rheumatic, prosthetic or cancerous pathologies.     

Évaluation de la tomoscintigraphie de perfusion pulmonaire couplée à la tomodensitométrie dans la prédiction de la fonction respiratoire postopératoire

IntroductionThe aim of our study was to evaluate the performances of pulmonary perfusion single photon emission computed tomography-computed tomography (SPECT-CT) with semi-automatic analysis for preoperative assessment for lung cancer.Materiel and methodThirty-five patients underwent preoperative lung perfusion scintigraphy (planar and SPECT-CT acquisition) from august 2016 to December 2017. Predicted postoperative forced expiratory volume in one second (ppoFEV1 and FEV1) by both methods were compared between each other and with the actual FEV1 measured 3 months after surgery. We also evaluated interobserver reproductibility of SPECT-CT semi-automatic segmentation software and the concordance of the data simulating reductions of 30 and 50% of acquisition time.ResultsFor 30 lobectomies and 5 pneumonectomies, the mean ppoFEV1 was 69%, a difference with actual ppoFEV1 of ?8% for SPECT-CT and ?6.77% for planar (P < 0,001). Both methods were well correlated, correlation coefficient was 0,827, 95% CI [0.686–0.909] but underestimated the actual poppFEV1. For SPECT-CT, interobserver reproducibility was excellent for pulmonary and lobar evaluation. The lobar functions, without 30 and 50% of the time acquisition, had absolute difference < 3% in comparison to native data.DiscussionWe did not prove SPECT-CT superiority on planar scintigraphy, actual FEV1 being difficult to predict because of confounding factors. But this exam could be useful before lobectomy and in cases of heterogeneous perfusion. Easily made, this method is reproducible even on data simulating a reduction of 50% of time acquisition.     

Intérêt de l’imagerie hybride TEMP-TDM dans l’exploration des infections

Single-Photon Emission Computed Tomography-Computerized Tomography (SPECT-CT) is a new hybrid technique which offers new diagnostical capabilities in daily nuclear medicine practice. This technique not only allows to acquire fusioned anatomic and functional images in the same time, but also, it increases sensitivity and accuracy of SPECT thanks to attenuation and scattering corrections got from transmission data. Until now, SPECT-CT data have been mainly obtained in oncology and cardiology, but now, many authors use it in many scan studies and particularly for infectious diseases. In inflammatory bowel diseases, SPECT-CT seems to increase diagnostical performances and to modify management of many patients. In suspected vascular sepsis, SPECT-CT could increase sensitivity of white blood cell scintigraphy but also its specificity thanks to spatial resolution of CT. In osteoarticular sepsis, SPECT-CT has the advantage to distinguish osteomyelitis from soft tissue infection and to guide biopsies. Nevertheless, in the light of PET-CT works, SPECT-CT development will probably modify nuclear medicine practice and many studies have to be conducted to highlight consensual procedure guidelines.     

Imaging Non-Specific Wrist Pain: Interobserver Agreement and Diagnostic Accuracy of SPECT/CT,MRI, CT,Bone Scan and Plain Radiographs

Purpose

Chronic hand and wrist pain is a common clinical issue for orthopaedic surgeons and rheumatologists. The purpose of this study was 1. To analyze the interobserver agreement of SPECT/CT, MRI, CT, bone scan and plain radiographs in patients with non-specific pain of the hand and wrist, and 2. to assess the diagnostic accuracy of these imaging methods in this selected patient population.

Materials and Methods

Thirty-two consecutive patients with non-specific pain of the hand or wrist were evaluated retrospectively. All patients had been imaged by plain radiographs, planar early-phase imaging (bone scan), late-phase imaging (SPECT/CT including bone scan and CT), and MRI. Two experienced and two inexperienced readers analyzed the images with a standardized read-out protocol. Reading criteria were lesion detection and localisation, type and etiology of the underlying pathology. Diagnostic accuracy and interobserver agreement were determined for all readers and imaging modalities.

Results

The most accurate modality for experienced readers was SPECT/CT (accuracy 77%), followed by MRI (56%). The best performing, though little accurate modality for inexperienced readers was also SPECT/CT (44%), followed by MRI and bone scan (38% each). The interobserver agreement of experienced readers was generally high in SPECT/CT concerning lesion detection (kappa 0.93, MRI 0.72), localisation (kappa 0.91, MRI 0.75) and etiology (kappa 0.85, MRI 0.74), while MRI yielded better results on typification of lesions (kappa 0.75, SPECT/CT 0.69). There was poor agreement between experienced and inexperienced readers in SPECT/CT and MRI.

Conclusions

SPECT/CT proved to be the most helpful imaging modality in patients with non-specific wrist pain. The method was found reliable, providing high interobserver agreement, being outperformed by MRI only concerning the typification of lesions. We believe it is beneficial to integrate SPECT/CT into the diagnostic imaging algorithm of chronic wrist pain.     

Scintigraphie des parathyroïdes double isotope Tc-MIBI/I dans l’hyperparathyroïdisme primaire : comparaison entre un protocole d’acquisition planaire et une TEMP de soustraction couplée à la TDM

In patient with primary hyperparathyroidism, preoperative imaging first objective is to determine accurately and reliably position and anatomic localization of enlarged parathyroid gland in order to guide surgeon for gland removal and to permit minimally invasive surgery. Although subtraction planar scintigraphy is an efficient imaging to diagnose hyperfunctioning parathyroid, the lack of anatomical reference for this single imaging technique could be obviated by hybrid imaging. We compared, in 23 patients with primary hyperparathyroidism, a planar scan of neck and mediastinum associated with a cervical anterior pinhole scan to a subtraction (¹²³I/^99mTc-MIBI) SPECT scan of neck and mediastinum fused with CT. Surgical and histopathologic findings were used as the standard of truth. Subtraction SPECT/CT appeared to be more sensitive and specific than planar protocol to diagnose and to accurately localize pathologic parathyroid. Sensitivity was 76 and 56 %, specificity was 100 and 80 % for hybrid SPECT/CT and planar protocol respectively. SPECT protocol was typically more efficient to diagnose pathologic parathyroid derived from upper gland and for patient with concomitant nodular goiter.     

Scintigraphie à l’OctréoScan® : aspects pratiques. Le point de vue du manipulateur

Evaluation of neuroendocrine tumors extent comprises a somatostatin receptor scintigraphy with OctréoScan^®. This examination begins with the radiopharmaceutical preparation and its quality control (dose, visual appearance, radiochemical purity, pH). The radiopharmaceutical is administered intravenously at a slow rate with respect of the contra-indications and recommendations. The patient's good respect of low residue diet and digestive preparations is essential for a good imaging quality. In addition, the technologist's psychological role (particularly for people suffering from claustrophobia) and adequate procedures must be taken into account. Several days are necessary to perform the examination that comprises whole body and planar (thoracic and abdominal) views, combined SPECT-CT imaging. This hybrid modality using fused images allows a good anatomical localisation of focal areas of increased uptake even in case of faint uptake. Some false-positive can be avoided (colonic stasis, gall bladder). SPECT-CT contribution to the diagnosis is certain.     

Infarctus osseux révélés par des arthralgies – Apport de la TEMP-TDM

We report the case of a 41-year-old woman, investigated for arthralgia of the knees, wrists and ankles who presented heterogeneous increased uptake of the distal extremities of femurs and the proximal extremities of tibias on the whole-body bone scintigraphy. A scintigraphy realized five years previously had shown a more homogeneous increased uptake in the same territory. The single photon emission computerized tomography guided by computerized tomography (SPECT-CT) centered on knees revealed several areas of heterogeneous increased uptake which corresponded to intraosseous “smoke twirled” lesions surrounded by calcifications. The clinical context, the location of the lesions and the morphological aspect are suggestive of bone infarcts. These infarcts were ascribed to a chronic alcoholism. Arthralgia could not be explained to this day.     

La perfusion pulmonaire en morphoTEMP dans le diagnostic de l’embolie pulmonaire : comparaison à la scintigraphie pulmonaire planaire de ventilation/perfusion

The aim of this study is to assess a new tool for the diagnosis of acute pulmonary embolism (PE): single-photon emission computed tomography lung perfusion imaging associated with unenhanced computed tomography (SPECT/CT) compared to planar ventilation-perfusion (VQ) lung scintigraphy.MethodsOne hundred and three patients with suspected acute PE underwent VQ scintigraphy (two scans were uninterpretable) followed by perfusion SPECT/CT. The two types of images were analysed separately: (1) according to the modified PIOPED scintigraphic criteria for VQ lung scan and (2) with regard to SPECT/CT mismatches suggestive acute PE (segmental perfusion defects detected on SPECT images not matched with CT abnormalities).ResultsOn average, the number of segmental perfusion defects per patient was higher with SPECT/CT than with planar scintigraphy (4.3 ± 3.6 versus 2.8 ± 2.6; p < 0.001). A mismatch was found with SPECT-CT in 0% (0/18) of normal scintigraphy, and 8% (3/39) for low, 32% (8/25) for intermediate and 74% (14/19) for high probabilities of PE at scintigraphy. The presence of a SPECT/CT mismatch was also associated with higher pretest probability of acute PE (p = 0.001), even for the 25 patients in the intermediate-probability subgroup (p = 0.02). Finally, a SPECT/CT match was found in 29 patients that was not suggestive of acute PE due to the presence, in areas with perfusion defects on SPECT images, of the following CT abnormalities: hypodensity and/or emphysema (71%), condensation or atelectasis (38%), pleural disease (7%), extrapulmonary structure (14%) and/or bronchial obstruction (7%).ConclusionIn patients with suspected acute PE, the results obtained with pulmonary SPECT/CT images are consistent with those obtained with VQ scintigraphy and the pretest probability of PE. Further studies comparing SPECT/CT imaging with angiographic techniques are now required to evaluate more specifically the diagnostic value of this new tool.     

Apport de l’imagerie hybride TEMP/TDM dans la détection des ganglions sentinelles : à propos de 32 cas

Objectives

Retrospective evaluation of the SPECT/CT role in the Sentinel Lymph Node identification.

Patients and methods

Thirty-two patients underwent a lymphoscintigraphy with SPECT/CT imaging. Those patients presented several cancer types (16 melanoma, one squamous cell carcinoma, three breast cancers, eight vulvar cancers, three cervical cancers).

Results

The scintigraphic detection rate was 81% with planar imaging while this rate was 89% with SPECT/CT. The SPECT/CT provided an additional quantitative information in 66% cases. Moreover, the quality of the interpretation was better in two different conditions (planar interpretation followed by routine and blinded SPECT/CT interpretation) with SPECT/CT. In our study, the false negative rate is 4.5%.

Conclusions

SPECT/CT provides quantitative and qualitative informations in the sentinel lymph node detection. Therefore, it can be a valuable tool for the surgeon to find and harvest the sentinel lymph node especially where the lymphatic drainage pattern can be unusual or hard to predict (cervical or trunk localisation). It's a new tool for preoperative detection and it can decrease the false negative rate.     

Lésion lytique douloureuse solitaire du tibia chez un homme de 23 ans correspondant à un fibrome non ossifiant : une pseudo-tumeur… si mal nommée !

A 23-year-old patient is referred for long-standing mechanical pain of right tibia. X-rays disclose an intra-cortical lytic area of tibial diaphysis. A bone scintigraphy including a SPECT-CT study discloses a hot spot matching with roentgenographic lytic focus. MRI exhibits heterogeneous signal abnormalities. A bone biopsy is decided. Pathological findings are consistent with a non-ossifying fibroma (NOF). From this case report, pathophysiology, pathology, natural history, multimodality imaging and differential diagnosis of NOF are sketched out.