Imagerie hybride TEMP/TDM de l’épiphysiolyse de hanche

Epiphysiolysis is a slipping of the superior femoral epiphysis under the effect of mechanical stresses. Rare event of end of growth, its incidence tends to increase with the increase of the overweight and the obesity in the child. The slipping can be progressive or acute and evolves spontaneously to fusion without pseudarthrosis or osteonecrosis but at the price of deformation and frequent secondary hip osteoarthritis. The treatment is surgical, with an iatrogenic risk of osteonecrosis if an osteotomy is performed. Although SPECT/CT bone scintigraphy has only a limited role at the initial stage (stage I), its major interest may be to evaluate the vitality of the capital femoral epiphysis, in particular a few weeks after surgery for epiphysiolysis with large displacement, before resuming hip support and/or in case of material MRI artifact resulting in an impossible assessment of vitality.     

Évaluation de l’irradiation additionnelle des patients de médecine nucléaire en imagerie hybride TEMP/TDM

One hundred and ten consecutive patients and 130 SPECT/CT examinations were involved in this retrospective study that focused on the evaluation of the excess of dose contributed by the CT to the patient during the SPECT/CT explorations, for routine examinations in nuclear medicine. The average age of patients was 53 years. In this study, it appeared that irradiation induced by a low dose CT combined with a SPECT is low compared to that of a diagnostic CT. The main risk on patients is the occurrence of radiation-induced cancer. In our study, this increased risk induced by the additional CT with low dose settings in line with SPECT examination, is not significant and does not exceed 0.026%. By weighing the diagnostic value of SPECT/CT examination with that of a stand-alone SPECT examination dosimetric “incremental cost” is justified because of its direct clinical benefit conveyed to the patient.     

Impact de l’imagerie hybride TEMP/TDM dans le diagnostic et la prise en charge de l’ostéome ostéoïde

IntroductionThe osteoid osteoma is a major bone benign tumors in children. It is more common in boys. The femoral and tibial locations account for 50% of cases. Clinically, it is revealed by nocturnal pain relieved by aspirin. The pain may precede by several months the radiographic abnormality. The purpose of our work is to elucidate the contribution of SPECT/CT in addition to the planar bone scintigraphy in the diagnosis and treatment of osteoid osteoma about two cases.Case reportClinical case No. 1: a 10-year-old child who presented a limp nocturnal pain in the left hip evolving for 4 months. The radiograph of the pelvis showed bone condensation subtrochanteric left femur. SPECT/CT showed an image for an osteoid osteoma. Surgical resection of the home revealed in the histological study an osteoid osteoma of the left femoral neck. The evolution was marked by an immediate pain relief and full recovery of the left lower limb mobility. Clinical case No. 2: an 11-year-old child who had a limp nocturnal pain at the upper end of the left femur evolving for 2 months. The pain was paroxysmal, relieved by salicylates. The X-ray of the pelvis showed a metaphyseal image with peripheral condensation and thickening of the cortex. SPECT/CT showed an image for an osteoid osteoma. The intervention was a tumor excision resection. Histopathological examination revealed a small nidus consistent with an osteoid osteoma. The evolution was marked by an immediate pain relief and normalization of the mobility of the left lower limb.DiscussionThe SPECT/CT can increase the sensitivity and specificity of planar bone scintigraphy. It confirms the location of osteoid osteoma and defines its anatomical relationships in order to optimize surgical management.ConclusionThe SPECT/CT contributes significantly to the diagnosis of osteoid osteoma when radiological images are atypical or unusual clinical expression.     

Apports de l’imagerie hybride TEMP/TDM dans le descellement aseptique de prothèse de hanche

Hip prosthesis loosening detection is a common indication for bone scan, however, the diagnosis can be difficult to confirm based solely on bone scan information which have a low specificity. The development of bone SPECT/CT hybrid imaging allows the correlation of two complementary modalities to palliate the low sensitivity of CT caused by metallic artefacts and the moderate specificity of bone scan. It becomes a necessity for nuclear medicine physicians to master the bases of pathological hip prosthesis radiological semiology. We propose in this review article to recall the physiopathology of prosthesis loosening then we will describe the radiological and scintigraphic characteristics of hip prosthesis loosening as well as its differential diagnoses and the benefits of other imaging modalities.     

Impact diagnostique de l’imagerie hybride TEMP/TDM dans la prise en charge des neuroblastomes. Expérience du service de médecine nucléaire du CHU Mohammed VI de Marrakech

IntroductionThe neuroblastoma is a malignant pediatric tumor of the peripheral sympathetic nervous system. This is the pediatric solid extracranial tumor most common and accounts for approximately 8 to 10% of childhood cancers. The diagnosis is based on imaging showing a tumor developed at the expense of the sympathetic nervous system, increased urinary catecholamines, increased uptake of meta-iodo-benzylguanidine (MIBG) and histology who finds a malignant proliferation of small round cells. An assessment of the tumor mass and its extension are required to assess the prognosis and adapt the treatment. The MIBG scintigraphy is a non-invasive imaging technique that can evaluate with a single review the totality of the tumor extension. The single-photon emission computed tomography/computed tomography (SPECT/CT) improves the sensitivity of the examination, it allows an anatomical and functional study and improves the anatomical localization of scintigraphic uptake observed. The purpose of our work is to illustrate the contribution of the SPECT/CT in addition to the planar MIBG scintigraphy in the diagnosis and staging of neuroblastoma about four cases.Case reportClinical case 1: a 4-year old child, presented for 2 months abdominal pain. In the clinical examination, he presented a hard abdominal mass, painless and right paramedian. Abdominal ultrasound showed a right retroperitoneal mass with lymph nodes. The dosage of urinary catecholamines was increased. The ¹³¹I-MIBG scintigraphy showed an image for a right adrenal neuroblastoma measuring 8.6 × 4.5 cm. Surgical excision of the adrenal mass revealed in the anatomopathologic study a malignant tumoral proliferation with round cells compatible with a neuroblastoma. Clinical case 2: a 10-month old infant, presented since 15 days an exophtalmia with poor general status. The clinical examination showed a right abdominal mass and a bilateral periorbital ecchymosis. The radiography of the thorax showed a widening mediastinal. Abdominal echography showed a tissular mass of the right adrenal gland with retroperitoneal lymph nodes and an ascites. The dosage of urinary catecholamines was increased. The ¹³¹I-MIBG scintigraphy showed a right adrenal neuroblastoma measuring 6.4 × 2.7 cm with orbital bone metastases in favor of a Hutchinson syndrome. Clinical case 3: a 2-month old infant, followed since 1 month for bilateral adrenal neuroblastoma. The clinical examination showed an important abdominal distension with bluish nodules under skin. The abdominal echography and the abdomino-pelvic TDM showed two adrenal masses corresponding to a bilateral neuroblastoma with liver metastases. The ¹³¹I-MIBG scintigraphy showed two adrenal masses measuring respectively 6.5 × 3.4 cm and 8 × 6 cm, with liver and skin metastases in favor of 4S neuroblastoma with bilateral adrenal tumors. Clinical case 4: a 3-year old child, followed for left adrenal neuroblastoma with multiple bone metastases. The clinical examination showed a left abdominal mass with exophtalmia and right palpebral ecchymosis. The radiography of the thorax showed a widening of the mediastin with repression of the paravertebral right line. Abdominal echography showed a left retroperitoneal tissular mass measuring 9.2 × 5.2 cm. The abdomino-pelvic TDM showed a left adrenal tumor with lumbar vertebral bone metastases. A first ¹³¹I-MIBG scan showed a left neuroblastoma with multiple bone metastases in the right orbit, the right humerus, the occipital bone, the right scapula and spine (D10, D11, L1, L3, S1). The child was treated by 5 courses of chemotherapy (protocol HRNLB/10). The ¹³¹I-MIBG scan control showed a regression of neuroblastoma size (1.4 × 1.2 cm) with loss of bone metastases of the occipital bone, the right scapula and spine.DiscussionThe MIBG scintigraphy is a simple, non-invasive examination that has excellent sensitivity and specificity in detection of neuroblastoma and especially in invasion bone marrow and in evaluation of the therapeutic response. The hybrid SPECT/CT imaging improve the performance of the scintigraphy as well in sensibility, toward the deep localization, as in specificity for images poorly defined in planar imaging.     

L’apport de l’imagerie hybride TEMP/TDM dans la prise en charge du cancer différencié de la thyroïde

IntroductionSingle photon emission computed tomography combined with a low dose computed tomography (SPECT/CT), is a hybrid imaging integrating functional and anatomical data. The purpose of our study was to evaluate the contribution of the SPECT/CT over traditional planar imaging of patients with differentiated thyroid carcinoma (DTC).MethodsPost-therapy iodine 131 (¹³¹I) whole-body scan followed by cervico-thoracic SPECT/CT, were performed in 100 patients with DTC.ResultsAmong these 100 patients followed for a predominantly papillary DTC, planar imaging and SPECT/CT, were perfectly concordant in 70% of patients and discordant in the remaining 30%. The use of fusion imaging SPECT/CT compared to conventional planar imaging allowed us to correct our therapeutic approach in 27% (27/100 patients), according to the protocols of therapeutic management of our institute.ConclusionSPECT/CT is a hybrid imaging modality which provides better identification and more correct anatomic localization of the foci of radioiodine uptake with impact on therapeutic management.     

Double ectopie thyroïdienne explorée par imagerie scintigraphique en mode hybride TEMP/TDM. À propos d’un cas

Ectopic thyroid is a rare entity resulting from developmental defect migration of thyroid gland during its embryogenesis. The circumstances and the age of ectopic thyroid discovery depend on the size and the functional character of ectopic focus. We are presenting the case of a 13-year-old boy who was followed for a growth delay with biological hypothyroidism. Planar ^99mTc scan and SPECT-CT have shown two foci of increased tracer uptake, one at the base of tongue and the second in prehyoid region. There was no tracer uptake in the thyroid bed. The two ectopic foci could not be visualized on ultrasonograpy and only one of them was detected at CT. This affirms the superiority, in terms of sensitivity and specificity, of morpho-functional imaging compared to purely morphological explorations in the detection of functional ectopic thyroid tissue to an optimal diagnosis approach, and therefore, a better orientation of the therapeutic strategy.     

Reproductibilité en scintigraphie osseuse planaire,TEMP et TEMP/TDM du pied douloureux : importance d’une sémiologie standardisée

AimThe diagnostic benefit of bone single photon emission computed tomography/computed tomography (SPECT/CT) is currently being demonstrated. However, until now, reproducibility has been poorly investigated. Therefore, a study was undertaken to assess intra- and inter-reader reliability comparing bone planar views, SPECT and SPECT/CT.MethodsThe study was carried out on a cohort of 50 adults consecutively referred to two distinct Nuclear Medicine departments for clinical and radiological suspicion of a reflex sympathetic dystrophy (RSD) of the foot. Each set of planar views and SPECT/CT was independently re-read by two Nuclear Medicine physicians (one junior and one senior expert) in a blinded fashion. An array of bone scan and CT semiological criteria depicting RSD and main differential diagnoses was initially elaborated. Reliability was measured by percentage of agreement and computation of unweighted kappa.ResultsAmong the 50 patients, only four actually suffered from RSD. Among the 46 patients who did not suffer from RSD, 28 were affected by miscellaneous skeletal lesions. This is the reason why the study shifted from focusing on RSD to the etiologic diagnosis of a painful foot. Percentage of inter-reader agreement rose from 74% for planar scintigraphy and SPECT to 96% for SPECT/CT. This study showed reliability indices higher than in literature mainly due to the use of predefined detailed semiological criteria and to the learning effect of the junior physician at senior physician school.ConclusionBone SPECT/CT provides significantly stronger intra-reader and inter-reader agreement in comparison to planar images and stand-alone SPECT.     

Intérêt de l’imagerie hybride TEMP-TDM dans l’histiocytose langerhansienne osseuse. À propos d’un cas

Langerhans’ cell histiocytosis is a non-malignant proliferative disease of unknown etiology. It is a rare illness affecting mainly children and young adults with a male predominance. It can affect one or many organs. The bone locations are the most frequent. We present one case of multifocal Langerhans’ cell histiocytosis in a 22-year-old male patient followed for diabetes insipidus with an enlargement of the pituitary stalk at the magnetic resonance imaging (MRI), and a lytic bone lesion revealed in lumbar spine (L2) by ^99mTc-HMDP scintigraphy conducted in planar mode, and then in Single Photon Emission Computed Tomography coupled to Computed Tomography (SPECT/CT) in hybrid mode. To this end, we propose to highlight diagnostic gain of SPECT/CT compared with SPECT and planar scintigraphy to characterize radiotracer uptake abnormalities in bone in Langerhans’ cell histiocytosis.     

Impact diagnostique de la TEMP–TDM dans l’exploration des tumeurs endocrines

Image fusion using single photon emission computed tomography–computed tomography (SPECT–CT) associates functional and morphological images. This study evaluates the added value of SPECT–CT, obtained with a hybrid SPECT–CT gamma camera, on anatomic localization and diagnostic impact in assessment of endocrine tumours and pheochromocytomas.MethodSix months prospective study was undertaken including 33 consecutive exams encompassing 20 Somatostatin Receptor Scintigraphies (SRS) and 13 ¹²³I-meta-iodo-benzyl-guanidine (MIBG) scans. Two experienced nuclear medicine physicians independently analysed independently planar and SPECT images in a first time, then, SPECT–CT fused images in a second time. They evaluated two parameters: SPECT–CT impact on anatomic localization (LA) and its diagnostic impact (ID). Each parameter was scored according three levels of evaluation.ResultsAn added value of SPECT–CT images was evidenced in 55% of cases on the anatomic localization and in 41% of the patients on the diagnostic impact. Therefore, a more important benefit was noted when SPECT was positive (LA: 90%; ID: 70%) than when it was negative (LA: 15%; ID: 8%). Furthermore, the added value proved higher for the SRS compared to MIBG scans.ConclusionSPECT–CT fusion images obtained by a hybrid system is more relevant to determine anatomic localization and more accurate than SPECT alone, particularly in the assessment of endocrine tumours. The added value of SPECT–CT seems to be lower for MIBG scans in the assessment of pheochromocytomas.     

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.     

Apport de la TEP/TDM au FDG en cancérologie de l’intestin grêle

This article focuses on the indication for FDG PET/CT in case of tumours of the small intestine, neuro-endocrine tumours excluded. The adenocarcinomas, lymphomas and sarcomas (including stromal tumours or GIST) are studied. There is no specific recommendation for FDG PET/CT in adenocarcinomas, extremely rare in comparison with colorectal adenocarcinomas. However, the utility of FDG PET/CT has been reported in clinical cases for detection and staging, especially in patients with high risk of developing the disease (Crohn's disease being the most important risk factor). The primary lymphomas of the small gut are also very rare, corresponding in all cases to non-Hodgkin lymphomas, for which the role of FDG PET/CT is recognised in follicular lymphoma, large B-cell lymphoma and Burkitt lymphoma. The stromal tumours correspond to the most frequent sarcomas. Stromal tumours in the small intestine are less frequent in the small intestine than in the stomach. The role of FDG PET/CT is well established in stromal tumours for the staging of the disease and for determining the efficacy of therapy with tyrosine kinase inhibitor. FDG PET is especially effective to evaluate the response since the radiologic criteria are difficult to assess, based not on the decrease of size of the lesions but on the decrease of density and of contrast enhance.     

Intérêt de l’imagerie hybride TEMP/TDM pour la détection de l’ectopie parathyroïdienne. Expérience du service de médecine nucléaire – CHU Mohammed VI,Marrakech

IntroductionHyperparathyroidism due to a parathyroid ectopia is a rare disease; it is the most common cause of persistent or recurrent hyperparathyroidism. Its treatment is exclusively surgical and the results of the surgery benefit from the contribution of preoperative imaging techniques. The aim of this work is to illustrate the interest of the single photon emission computed tomography/computed tomography (SPECT/CT) in the detection and treatment of ectopic parathyroid orientation.Case reportClinical case 1: a 41-year-old patient was followed for persistent primary hyperparathyroidism revealed by brown tumors at the level of the lower extremity of the right femur and tibia. The rate of parathormone was 1987.4 pg/mL. The cervical echography and the scanning were not decisive. The SPECT/CT, performed during a ^99mTc-MIBI scintigraphy and the same for the 2nd clinical case, has showed an area of high uptake projecting behind the left sternoclavicular joint. The diagnosis of ectopic parathyroid localization was retained. Resection and pathologic examination of the surgical specimen revealed parathyroid adenoma tissue. The evolution was marked by a normalization of the rate of parathormone. Clinical case 2: a 71-year-old patient who presents a clinico-biological board of primitive persistent hyperparathyroidism. A first scintigraphy (^99mTc-MIBI) realized in 2010 was negative. The rate of parathormone was 969 ng/L, the rate of calcium was 2.90 mmol/L. Two cervical ultrasound were normal. The SPECT/CT has objectified an area of high uptake in projection at the upper floor of the middle mediastinum. The diagnosis of ectopic parathyroid localization was retained. Surgical resection and histological study revealed a parathyroid adenoma tissue. The evolution was marked by a normalization of the rate of parathormone.DiscussionThe SPECT/CT has an important role in the management of patients with persistent or recurrent hyperparathyroidism. It can usually visualize ectopic parathyroid injury, specify its size and anatomic relationships to optimize surgical management.     

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.     

Performances de la scintigraphie osseuse TEMP/TDM en comparaison avec l’IRM dans le diagnostic des fractures occultes du carpe

BackgroundThe diagnosis of wrist fractures, especially scaphoid fractures, remains a challenge because of non-union risk. Currently new hybrid technologies are emerging such as single photon emission computed tomography–computed tomography (SPECT/CT) systems, which combine functional and anatomical data sets. So, we wanted to evaluate the utility of SPECT/CT in the management of occult carpal fractures.Patients and methodsAll patients addressed to the orthopaedic department at Brest University Hospital for wrist pain after trauma and with initial normal plain radiographs were prospectively included. Patients with normal radiographs but a strong suspicion of clinical fracture underwent a bone SPECT/CT and an MRI of the wrist. Therapeutic management took into account the results of all modalities and all patients were followed for at least 6 months and reviewed by the same surgeon. SPECT/CT findings were compared to those of the other modalities and follow-up.ResultsFrom December 2009 to May 2011, 57 patients were enrolled. Fifty-seven SPECT/CT and 52 MRI were performed. Twenty-six patients presented a positive SPECT/CT (31 fractures). MRI concluded to abnormalities for 26 patients (20 fractures and 17 bone bruises). Sensitivity, specificity, positive predictive value, negative predictive value and accuracy per patient were respectively 88.46%, 96.15%, 95.83%, 89.29%, 92.3% and per lesion 75.68%, 96.15%, 96.55%, 73.53%, 84.13%. Interobserver reproducibility for SPECT/CT was excellent. Only one patient presented a non-union at the follow-up whereas both investigations were positive.ConclusionThis study highlights the good performances of SPECT/CT, which allows the detection of most occult carpal fractures. When a carpal occult fracture is clinically strongly suspected, SPECT/CT might be proposed in first intention after normal radiographs.     

Intérêt de l’imagerie hybride TEMP/TDM dans la localisation des glandes parathyroïdes ectopiques : à propos de 3 cas

The presence of a parathyroid gland in ectopic position constitutes one of the leading causes of surgery failure. For this purpose, scintigraphy takes a major place in the anatomical localization of pathological parathyroid and so facilitates its treatment. The advent of hybrid cameras combining single photon emission tomography to CT (SPECT/CT) has further strengthened the contribution of this imaging modality in the precise localization of ectopic parathyroid and its anatomical relationships. The objective of our work is to illustrate the interest of hybrid imaging SPECT/CT, compared to planar scintigraphy and ultrasounds within the framework of primary hyperparathyroidism, particularly ectopic situation through three cases.