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.     

Démarche sémiologique en TEMP/TDM osseuse. Une approche diagnostique intégrée de l’imagerie hybride

This article sketches out properties of the three modalities of bone scintigraphy: planar imaging, SPECT, SPECT/CT. Technical principles of SPECT/CT are developed. An integrative diagnostic approach of SPECT/CT patterns is then applied to malignant and benign skeletal conditions.     

Évaluation par la TEMP–TDM des lésions classées indéterminées en scintigraphie osseuse chez les patients de cancérologie

The aim of the present study was to investigate the contribution of the single photon emission computed tomography/computed tomography (SPECT/CT) in cancer patients and to evaluate its ability to correctly classify indeterminate lesions on planar bone scintigraphy (PBS).MethodsFrom November 2006 to August 2007, all patients with confirmed malignancy, whose PBS showed indeterminate lesions, underwent without delay a SPECT/CT. The study included 120 patients (67 men, 53 women), with a mean age of 69 ± 12 years (range 42–96 years). The patients with obvious metastases, important pains or who did not accept the examination were excluded from the study. The location of the lesions was described either as precise, probable or indeterminate. The lesions were classified either as definitely malignant, definitely benign or indeterminate.ResultsBreast, prostate, lung and kidney neoplasms represented approximately 80% of all cancers. The PBS highlighted 267 lesions of location either as precise (n = 29), probable (n = 129) or indeterminate (n = 109), classified either as definitely malignant (n = 28), definitely benign (n = 27) or indeterminate (n = 212). The SPECT/CT revealed 440 lesions, of location either as precise (n = 353), likely (n = 39) or indeterminate (n = 48), classified either as definitely malignant (n = 84), definitely benign (n = 305) or indeterminate (n = 51). Thoracic and lumbar spine and pelvis were the locations of 79% of the scintigraphic lesions and of 88% of the osseous metastases. SPECT/CT modified the final report of 80 patients, by excluding from metastases (n = 2), by showing metastases (n = 23) and by showing the benign character of indeterminate lesions (n = 55). Moreover, 69 patients out of 120 (> 57%) had an evolution confirmed with 35 true positives, 31 true negatives, one false negative and two patients with indeterminate lesions on SPECT/CT, without osseous metastasis.ConclusionThe assessment of the indeterminate scintigraphic lesions of oncologic patients benefits from the SPECT/CT. The lesion-based analysis showed that the SPECT/CT detected more lesions (+64%) and correctly classified 88% of the detected lesions. The patient-based analysis highlighted that SPECT/CT modified the final report for more than 66% of the patients. The follow-up showed that SPECT/CT correctly classified for more than 95% of the patients.     

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.     

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.     

Validation du logiciel de semi-quantification DaTQUANT® dans l’aide à l’analyse visuelle en TEMP au 123I-FP-CIT dans l’étude des pathologies neurodégénératives

ObjectiveSemi-quantification is a valuable tool increasing the diagnosis accuracy of the single photon emission computer tomography (SPECT) with FP-CIT-¹²³I (DaTSCAN^®), particularly in cases where visual analysis is unclear and especially on the posterior putamen. The DaTQUANT^® software (GE^® Healthcare), allows a quick and simple uptake assessment on several regions of interest. It also provides deviation values compared to a database of healthy subjects obtained in the ENC-DAT project. However, any threshold value is currently validated routinely.Patients and methodsA retrospective study was conducted in 55 patients (33 men, 22 women) referred for a suspicion of neurological disorders and who underwent SPECT imaging with DaTSCAN^® on camera D670 GE^®. Final diagnosis made by neurologist time after the SPECT was established as a reference, reinforced by clinical evolution. Analysis was initially visual without semi-quantitative results, realized by two experimented nuclear physicians, and then semi-quantitative analysis was made by DaTQUANT^® with calculation of Youden indices and ROC curves so as to define threshold values for six regions of interest (caudate, putamen anterior, posterior putamen, bilaterally).ResultsInterobserver match in the blind visual analysis was excellent with kappa coefficient = 0.91, CI at 95% = [0.87–0.95]. The semi-quantitative and statistical analysis by DaTQUANT^® determined pathological threshold values for each region of interest, setting a standard deviation percentage from a database of healthy subjects, worth −16.3% for the right posterior putamen (sensitivity of 100% and specificity of 88%) and −18.3% for the left posterior putamen (sensitivity of 100% and specificity of 97%).ConclusionThe pathological threshold values defined by our study would improve the data analysis obtained from DaTQUANT^® software and would support the DaTSCAN^® visual analysis. Nevertheless, such statistical values are complementary to visual analysis.     

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.     

Cancer de la prostate et masses abdominopelviennes fixant le 99mTc-HDP. Apport de la tomographie d’émission monophotonique couplée à la tomodensitométrie (TEMP–TDM)

We report the case of a 63-year-old man, investigated for staging of a prostatic cancer, diagnosed by biopsy, following a rise in the prostatic specific antigen (PSA) on a systematic assessment. The interrogation before examination revealed signs of beginning right crural neuropathy. The hydroxymethylene diphosphonate technetium 99m-labeled (^99mTc-HDP) whole-body bone scintigraphy highlighted two extraosseous uptake images, the first of moderated intensity in the right iliac area, the second milder, in the abdominal median area. Osseous metastases were not visualized. The single photon emission computerized tomography guided by computerized tomography (SPECT/CT) identified the median abdominal mass which corresponded to a bulky aneurysm of the under renal abdominal aorta. The right iliac mass could be accurately analyzed and differentiated from the various organs of the abdominopelvic cavity. Its lymphatic origin was hypothetised, but the diagnosis of lymphatic metastasis of the prostatic cancer was obtained by the pathologic examination of CT scan-guided biopsy.     

Enjeux,défis,opportunités et stratégie durable d’implantation de l’imagerie hybride TEMP/TDM dans un pays à ressources médicales limitées,la Côte d’Ivoire

From HO Anger's analogic gamma camera to digital camera, developed countries are at the time of hybrid cameras SPECT/CT and PET/CT. Sub-Saharan black Africa in the image of Côte d’Ivoire, a country with limited medical resources shows an important delay in the evolution of the health system in general and particularly in medical imaging equipment. The purpose of this paper was to approach the issues, challenges and sustainable strategy for the implementation of hybrid imaging SPECT/CT in a developing country where the rate of morbidity and mortality remains high due to infectious but also cancer diseases because of the inadequacy of the health technical platform. To address these challenges, Côte d’Ivoire like many countries in sub-Saharan Africa with limited medical resources must design, test and develop clinical strategies adapted to developing countries. Health authorities of this country must develop a policy for sustainable financing of medical imaging, including the training of the adequate health personnel according to a model of corporate leadership. In this perspective, Côte d’Ivoire must have a SPECT/CT instead of a simple gamma camera. This would allow to optimize its diagnostic health system in oncology, bone and joint disease and in many other medical disciplines. And especially since the SPECT/CT is a high-performance device that has largely demonstrated its diagnostic efficiency and that can be used as SPECT alone or as isolated CT. In addition, this country should take over digital imaging in the context of cooperation with some countries of Africa and Europe ahead in the field of modern medical imaging, seeking assistance from international organizations (IAEA, RAD-AID, WHO,…). Finally this country should implement methods of assessment, types of performance indicators to guide planning for future projects of its system.     

Apport de la TEMP/TDM pour la détection du ganglion sentinelle dans les cancers du col utérin et de l’endomètre

The sentinel lymph node procedure is still under evaluation for the management of cervical and endometrial carcinomas. The aim of our study was to determine the diagnostic accuracy of single-photon emission computed tomography/computed tomography (SPECT/CT) for preoperative sentinel lymph node mapping in uterine cancers. Sixty-eight patients with cervical (n = 42) or endometrial carcinoma (n = 26) underwent preoperative lymphoscintigraphy for sentinel node mapping. Sentinel node detection rate with conventional planar imaging was similar to that of SPECT/CT (87.1 versus 91.8 %) in the whole cohort. However, SPECT/CT detected a higher number of sentinel nodes in more than one third of patients, affected by either cervical or endometrial carcinoma. The rate of non or insufficiently contributive procedures (lack of uptake or unilateral uptake) in endometrial carcinomas was 47 % with conventional planar imaging, and 30 % with SPECT/CT. Sensitivity of both procedures for the detection of metastatic nodes was 81.8 %, compared to 100 % for the intraoperative combined detection (gamma probe sonde and blue dye). The impact of SPECT/CT for the sentinel lymph node detection in cervical and endometrial carcinomas needs further evaluation. Nevertheless, SPECT/CT may provide additional information when conventional planar imaging detects only unilateral uptake, may improve identification of atypical localizations, and facilitate surgical approach.     

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.     

TEMP/TDM et scintigraphie osseuse en cancérologie : impact d’une acquisition scannographique basse dose chez les patients avec foyer isolé suspect ou de nature indéterminée

AimTo evaluate the usefulness of a low dose SPECT/CT and the added value of an additional “diagnostic” centred CT-scan in cancer patients with a solitary focus observed on planar whole-body bone scintigraphy (PWBS) and classified as indeterminate or suspicious.Material and methodsSixty consecutive patients underwent a low dose SPECT/CT acquisition (120 kV, 30 mAs, 3 mm slice thickness) followed by a “diagnostic” CT-scan (120 kV, 100 mAs, 1.25 mm slice thickness) centred on the focus. The first observer considered prospectively WBS, low-dose SPECT/CT and finally the centred SPECT/CT. A blinded review was performed by a second observer.ResultsPWBS depicted solitary indeterminate or suspicious foci in 38 and 22 patients, respectively. SPECT/CT acquisitions clarified 73% (44/60) of the foci. Additional diagnostic CT-scan altered low-dose SPECT/CT results in nine patients. Additional foci (not found by PWBS) located outside the scanning area of the centred diagnostic CT-scan were found in 20 patients. Inter observer agreement for PWBS, low-dose SPECT/CT and diagnostic SPECT/CT was equal to 0.542, 0.68 and 0.694, respectively. ROC analysis showed no difference between low-dose SPECT/CT and diagnostic SPECT/CT for observer 1 and observer 2.ConclusionThis study shows that a conventional low-dose SPECT/CT in patients presenting with a solitary focus on PWBS is sufficient to improve both accuracy and inter observer variability of bone scanning. A CT volume session should not be limited to the area of the solitary focus since additional foci located outside the centred CT-scan frequently occurred.     

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.     

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.     

Taux de fixation de la pointe du ventricule gauche et correction d’atténuation TEMP/TDM dans la scintigraphie myocardique de perfusion chez les patients non ischémiques

Introduction

Attenuation correction (AC) has been shown to improve the accuracy of myocardial perfusion single photon emission computed scintigraphy (SPECT). It often reveals a decrease in apical uptake in the AC of the left ventricular (LV) in non-ischemic patients. We aimed to identify the parameters that could affect the apical radiotracer uptake in non-ischemic patients.