Partie 5. Pathologies tumorales

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.     

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.     

Partie 1. Généralités

Bone scintigraphy is a nuclear imaging scan using a radiopharmaceutical composed of a bisphosphonate coupled to a radionuclide (technetium 99m). 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.     

Partie 3. Infections osseuses (hors greffe sur matériel)

Bone scintigraphy is a nuclear imaging scan using a radiopharmaceutical composed of a bisphosphonate coupled to a radionuclide (technetium 99m). 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.     

Partie 4. Rhumatologie

Bone scintigraphy is a nuclear imaging scan using a radiopharmaceutical composed of a bisphosphonate coupled to a radionuclide (technetium 99m). 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.     

Partie 7. Spécificités pédiatriques

Bone scintigraphy is a nuclear imaging scan using a radiopharmaceutical composed of a bisphosphonate coupled to a radionuclide (technetium 99m). 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.     

Intérêt de l’imagerie scintigraphique, à Madagascar,dans le diagnostic de l’adénome parathyroïdien ectopique – à propos d’un cas

This study reports the first case of ectopic parathyroid adenoma, diagnosed in the Department of Nuclear Medicine in Antananarivo. This clinical vignette illustrates the interest of the MIBI-Tc-99 m scan in locating this adenoma and its diagnostic confirmation after six years of erratic diagnosis. A whole body bone scintigraphy has also allowed to assess the state of bone metabolism and study outbreaks of fracture. The parathyroid scintigraphy was carried out after intra-venous administration of 666 MBq of MIBI-Tc99m. Dynamic images, static early and late static were acquired with a gamma camera E-Cam Siemens. The whole body bone scan was carried out after administration of 555 MBq of MDP-Tc-99 m. The results evidenced the presence of an para-aortic increased uptake area pointing to a left parathyroid adenoma. The persistence of a late left submaxillary increased uptake area raises, however, a reservation about the existence of a second adenoma. The bone scan displayed global skeletal remodeling, non suggestive of metastases, as it was mentioned with the CT-scan. In a diagnostic tools limited environment, skeletal pain refractory to painkillers, a chronic hypercalcemia associated with an increased parathyroid hormone level, should trigger the scintigarphic exploration in order to avoid bone and renal complications.     

Intérêt de la tomoscintigraphie cardiaque à la 123I-mIBG couplée à la perfusion myocardique dans le diagnostic de l’atrophie multisystématisée

ObjectiveThe aim of this prospective study is to assess the pertinence of using ¹²³I-mIBG myocardial tomoscintigraphy coupled with perfusion scintigraphy as a diagnostic tool, to discriminate between multiple system atrophy (MSA) and idiopathic Parkinson's disease (PD) at first guided by clinical data and L-DOPA tests.Material and methodsForty patients, aged from 43 to 78 years (median 62 years) with Parkinson's syndrome were studied. Nineteen had a diagnosis of PD (criteria of brain bank) and 21 AMS (Gibbs criteria). All were given test to acute L-DOPA. Chest-centered planar imaging (128 × 128 matrix, 5 minutes of duration) is performed at 1 hour and 4 hours after injection of 220 MBq of ¹²³I-mIBG, in addition a non-synchronised tomoscintigraphy (64 × 64 matrix, 32 images of 50 seconds , zoom 1.45) was performed after the 4th hour and 15 minutes after injection of 200 to 400 MBq of ^99mTc-tetrofosmin. Besides neurological data, the parameters retained for comparison purposes with ¹²³I-mIBG cardiac tomoscintigraphy were patients’ age, duration of disease and L-DOPA test results. Two regions of interest (ROI) identical in size and in shape are used for ¹²³I-mIBG uptake quantifications (H/M and washout [Wo]). The first one was placed in projection of mediastinum (M) and the other one in projection of heart (H).ResultsWe found an overall decreased uptake of the myocardial ¹²³I-mIBG without perfusion abnormality in 15 of 19 patients with PD and 11 among them were L-DOPA sensitive (L-DOPA test greater than 30%). Normal tracer uptake with ¹²³I-mIBG associated with an almost quite normal perfusion was seen in 15 of 21 patients with MSA and they were little or not L-DOPA sensitive (L-DOPA test less than 30%). Therefore, 10 discordant cases (25%) between cardiac scintigraphy and clinical evolution of disease with also discordant L-DOPA tests were observed. In the PD group, quantification of data enhanced the diagnostic decision with low heart to mediastinum ratio (H/M) (1.32 ± 0.15 at the early stage and 1.25 ± 0.13 at the later stage). In the MSA group, the uptake of ¹²³I-mIBG (1.66 ± 0.43 at the early stage and 1.72 ± 0.42 at the later stage) was comparable to literature data, however, with significant inter-individual variations. The association of data of scintigraphy with L-DOPA test allows to improve sensitivity in 84% and specificity in 90.5%.ConclusionOur prospective study of 40 cases shows the relevance of cardiac sympathetic postganglionic imaging with ¹²³I-mIBG coupled with myocardial perfusion scintigraphy to discriminate between MSA and PD with a higher sensitivity (71.4%) compared to the test with L-DOPA but a lower specificity (78.9%) than the L-DOPA. The difficulty of diagnosis is firstly linked to damage occurring to both the pre- and postganglionic sympathetic systems in patients with MSA and secondly to the integrity of the sympathetic nerve endings in patients with PD. However, the association of data of scintigraphy with L-DOPA test show a significant improvement of sensibility (84%).     

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.     

18F-sodium fluoride PET/CT indications

¹⁸F-sodium fluoride uptake mechanism is based on the fluoride ion exchange, with a hydroxyl group of the hydroxyapatite being at the surface of the bone crystals and thus forming fluorapatite, especially at sites with a high rate of bone remodeling. ¹⁸F-fluoride shows a lower protein binding and faster plasma clearance with respect to ^99mTc-diphosphonates (twice increased bone uptake). The adult dose range is 185–370 MBq, whereas in children it is advisable to adjust dose (0.057 mCi/kg). The acquisition time of the ¹⁸F-fluoride PET study is similar to that of ¹⁸F-FDG one (60 ± 30 minutes). The CT is required for attenuation correction (low amperage 30 mAs) but also allows artifact reduction and quantification. ¹⁸F-fluoride PET shows high sensitivity for detection of bone metastases, affecting its specificity. However, CT addition may increase specificity, resulting in a high accuracy of ¹⁸F-fluoride PET/CT. Given its uptake mechanism, its sensitivity is higher for mixed and blastic metastases rather than for lytic ones. Multiple studies have shown that the sensitivity of the ¹⁸F-fluoride is higher than bone scan, including whole-body bone SPECT. However, ¹⁸F-fluoride PET/CT should find their real indications in the current algorithms of clinical practice.     

Froid hivernal et port exclusif de chaussures de sport en tissu par une adolescente : effets tardifs en tomoscintigraphie osseuse et en résonance magnétique nucléaire

We present a rare clinical case of a 14-year-old adolescent girl from central Switzerland with an algoneurodystrophy of the left foot and leg 6 months after grade I frostbite(s) of the feet. After 6 months of constant pain of the digits, not attenuated by non steroid anti-inflammatory drugs, MRI of the feet reveals a predominantly left-sided and distal medullary edema, limited to the phalanges. Bone scintigraphy shows a predominantly left-sided diffuse feet hypoperfusion, coupled with an increased bone uptake of the left leg at late images. Inadequate life-style of adolescents, i.e., exclusively wearing shoes made of cloth and not of leather – even with temperatures below 0 °C in winter – might be a cause of chronic pain of foot digits. This is a rare demonstration of late effects of cold on foot digits by combined MRI and bone scintigraphy. Algoneurodystrophy in children and adolescents is an underdiagnosed clinical entity.     

Prevalence of transthyretin cardiac amyloidosis in elderly patients diagnosed with heart failure

ObjectiveThere is increased interest in studying ATTR-CA, a pathology that primarily affects patients of geriatric age and is frequently underdiagnosed. We aim to establish the prevalence of ATTR-CA in a cohort of patients with a history of HFpEF and to describe its characteristics.MethodsWe conducted a prospective observational study. Patients ≥75 years, clinical history of HFpEF, atrial dilation ≥34 ml/m² and left ventricular wall thickening >13 mm, were included. Demographic and analytical parameters were collected, and a comprehensive geriatric assessment was performed, along with a transthoracic echocardiogram and cardiac scintigraphy. Finally, telephone follow-up was carried out at 6 and 12 months.Results50 patients were recruited, mean age 86 ± 6 years, 54% women. Age and functional class (I–II vs. III–IV) were factors associated with presenting with ATTR-CA. Patients with positive scintigraphy had a median time to admission of 5.2 months (confidence interval [CI] 95% 0–10.9), while in those with negative scintigraphy, it was 12.2 months (95% CI 11.7–12.8); log-rank: p = 0.064. Patients with positive scintigraphy had a median time to the combined endpoint (death and readmission) of 1.9 months (95% CI 0–6.1), and patients with negative scintigraphy of 11.9 months (95% CI 11.7–12); log-rank: p = 0.027.ConclusionsATTR-CA appears to be a prevalent etiology in elderly patients within the spectrum of HFpEF. Patients with a diagnosis of ATTR-CA had a shorter time to admission for HF and the combined event of death and admission than patients with a negative result on scintigraphy.     

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.     

Découverte fortuite de fixations colorectales focales du FDG en TEP/TDM : corrélation aux données de la coloscopie

PurposeFDG-PET is an established tool for the diagnosis of recurrent or metastatic colorectal carcinoma. Several case series suggest that FDG-PET often detects incidental adenomatous polyps or colorectal adenocarcinomas. The aim of this study was to correlate unexpected colorectal foci of FDG uptake to pathology findings after systematic colonoscopy.Patients and methodsWe reviewed the records of 3541 patients who underwent FDG PET/CT in our institution over a 30-month period for the assessment of a known or suspected malignancy. In 85 of them, incidental, nodular shaped and well-circumscribed foci of abnormal uptake were identified in the area of the colon or rectum. Patients with segmental or diffuse abnormal colorectal uptake were excluded, as well as patients with known benign or malignant colorectal disease. Colonoscopy and complete pathology report was available in 29 patients. Maximal standardized uptake value (SUV_max) was measured in all lesions.ResultsUnexpected colorectal foci of FDG uptake were associated with colonoscopic abnormalities in 23 patients (true positive rate: 79 %). Adenocarcinomas were found in six patients (SUV_max = 7.3 ± 2.6), tubulous adenomas in four patients (SUV_max = 7.3 ± 4.9) and tubulovillous adenomas in 12 patients (SUV_max = 4.2 ± 1.1). Hyperplasic polyps with no sign of dysplasia were found in the last patient (SUV_max = 3.3). Concomitant CT abnormalities were found on PET/CT fusion in eight patients and consisted of wall thickening (n = 5) or nodular mass (n = 3). Conversely, PET was falsely positive in six patients (21 %), with no concomitant CT abnormalities and no abnormal findings at endoscopy (SUV_max = 6.2 ± 2.8, no significant difference with true positive lesions).ConclusionOur findings emphasize the need to perform a colonoscopy in front of incidental nodular colorectal foci of FDG uptake because malignant or pre-malignant neoplasms, which are not clinically apparent, are found in more than three-quarter of cases.     

Changes of net charge and α-helical content affect the pharmacokinetic properties of human serum albumin

The pharmacokinetics of 17 genetic variants of human serum albumin with single-residue mutations and their corresponding normal albumin were studied in mice. In all cases, the plasma half-life was affected, but only variants with + 2 changes in charge prolonged it, whereas changes in hydrophobicity decreased it. Good positive and negative correlations were found between changes in α-helical content taking place in domains I + III and domain II, respectively, and changes in half-lives. No correlation was found to type of mutation or to changes in heat stability as represented by ΔH_v. Liver and kidney uptake clearances were also modified: α-helical changes of domains I + III showed good negative correlations to both types of clearances, whereas changes in domain II only had a good positive correlation to kidney uptake clearance. No correlation between the other molecular changes and organ uptakes was observed. The relatively few correlations between changes in molecular characteristics and the organ uptakes of the variants are most probably due to different handling by plasma enzyme(s) and the various types of cell endocytosis. Of the latter, most lead to destruction of albumin, but at least one results in recycling of the protein. The present information should be useful when designing recombinant, therapeutical albumins or albumin products with a modified plasma half-life.     

Studies on phosphate uptake by Acinetobacter calcoaceticus under aerobic conditions

Acinetobacter calcoaceticus was cultivated in a well-aerated stirred tank reactor and its phosphate uptake capacity was investigated. Statistical media optimization was done to figure out favourable growth conditions of Acinetobacter calcoaceticus NRRLB-552. Plackett–Burman design was used to figure out the key nutrients (sodium acetate, ammonium chloride and calcium chloride) featuring high growth and/or uptake of phosphate. The optimal concentrations for these nutrients were (sodium acetate 5.0 g/l, ammonium chloride 0.67 g/l, calcium chloride 0.05 g/l) obtained by central composite design (CCD) protocols and verified in shake flask cultivations. Predicted and experimental dry cell weights obtained using the optimized media were 2.046 and 2.54 g/l indicating 97% agreement. The optimal values of pH and temperature for growth and phosphate uptake were found to be 7.69 and 31.86 °C, respectively, using CCD. Batch kinetics was also established in shake flask and fermenter using optimized medium and environmental conditions. Phosphate uptakes of 21 mg/g biomass and 36 mg/g biomass were obtained in shake flask and fermenter, respectively. The possible inhibition of nutrients (carbon, nitrogen and phosphate) was also established under shake flask cultivation conditions. Growth of the bacteria was inhibited at a concentration higher than 0.4% carbon and 0.6% nitrogen. However increasing concentration of phosphate did not show any inhibitory effect on growth. The above kinetics and inhibition data will serve as suitable database for the development of a mathematical model for growth and its use will be able to facilitate appropriate reactor design for the removal of phosphates from industrial effluents.     

Place des explorations isotopiques dans les otites externes nécrosantes

BackgroundThe necrotizing otitis externa (NOE) is potentially lethal which mainly occurs on the most among the elderly and diabetic. The aim of our study was to evaluate the contribution of isotopic explorations in diagnosis, staging and monitoring of the NOE.MethodsOur retrospective study was about 50 patients with a strong suspicion of NOE who benefited a bone and/or gallium scintigraphy.ResultsOur population was composed of 38 men and 12 women with mean age of 68 years. All patients were diabetic. The most common complaint was otalgia (98% of cases). The sensitivity of computed tomography (CT) which was performed in 84% of cases was 66.6% of cases. Bone scintigraphy (BS) was performed in all patients showing increased uptake in the temporal region in 90% of cases. An extension to surrounding structures was objectified in 26% of cases. Follow-up Ga 67 SPECT was performed in 56% of cases, demonstrated increased uptake at the temporal region in 43% of cases. The statistical study showed that only the presence of an extended tympanic lysis on CT was statistically significant to the positivity of BS (P = 0.036). No statistically significant correlation was found between all other CT abnormalities, clinical and biological signs and the positivity of bone scintigraphy.ConclusionIsotopic explorations were a great contribution in the management of the NOE. At the initial phase, the BS allowed to confirm very early an existence of osteomyelitis of the skull base. During the follow-up, the gallium-67 scan allowed the following of the evolution of infectious process.     

Sodium-dependent vitamin C transporter SVCT2: Expression and function in bone marrow stromal cells and in osteogenesis

Ascorbic acid (Vitamin C) has a critical role in bone formation and osteoblast differentiation, but very little is known about the molecular mechanisms of ascorbic acid entry into bone marrow stromal cells (BMSCs). To address this gap in knowledge, we investigated the identity of the transport system that is responsible for the uptake of ascorbic acid into bone marrow stromal cells (BMSCs). First, we examined the expression of the two known isoforms of the sodium-coupled ascorbic acid transporter, namely SVCT1 and SVCT2, in BMSCs (Lin ? ve Sca1 + ve) and bone at the mRNA level. Only SVCT2 mRNA was detected in BMSCs and bone. Uptake of ascorbic acid in BMSCs was Na⁺-dependent and saturable. In order to define the role of SVCT2 in BMSC differentiation into osteoblasts, BMSCs were stimulated with osteogenic media for different time intervals, and the activity of SVCT2 was monitored by ascorbic acid uptake. SVCT2 expression was up-regulated during the osteogenic differentiation of BMSCs; the expression was maximal at the earliest phase of differentiation. Subsequently, osteogenesis was inhibited in BMSCs upon knock-down of SVCT2 by lentivirus shRNA. We also found that the expression of the SVCT2 could be negatively or positively modulated by the presence of oxidant (Sin-1) or antioxidant (Ascorbic acid) compounds, respectively, in BMSCs. Furthermore, we found that this transporter is also regulated with age in mouse bone. These data show that SVCT2 plays a vital role in the osteogenic differentiation of BMSCs and that its expression is altered under conditions associated with redox reaction. Our findings could be relevant to bone tissue engineering and bone related diseases such as osteoporosis in which oxidative stress and aging plays important role.     

La concentration plasmatique de PTH permet-elle de sélectionner les patients atteints d’hyperparathyroïdie secondaire pour bénéficier de la scintigraphie double isotope MIBI (99mTc)/123I préopératoire ?

The utility of preoperative scintigraphy in case of secondary hyperparathyroidism is questioned by some authors. Obviously, an imaging modality that will detect all hyperplastic glands, including the ectopic ones, would be of interest in those patients at high risk for surgery. However, scintigraphy has a limited detection rate in some patients. We investigated whether one of the following parameters would identify a subgroup of patients in whom the detection rate would be optimal: age, gender, hemodialysis and duration since its onset, and plasma levels of parathyrin (PTH).MethodsRetrospective series of 38 patients referred for preoperative parathyroid scintigraphy due to secondary hyperparathyroidism who then underwent parathyroidectomy. Scintigraphy was performed 20 min and then 3 h after injection of 8 MBq/kg of sestamibi (^99mTc) with a previous ingestion of 0.1 MBq/kg iodine-123, 3 h before.ResultNo significant correlation was observed between the number of glands detected on scintigraphy (and confirmed by postoperative histology) and plasma PTH levels (r = ?0.17). A weak positive correlation (r = +0.34) was noted in the group of six non-hemodialysed patients. No significant relationship between this number of detected glands and a clinical parameter was observed.ConclusionIn our experience, these parameters do not permit to select, among patients with secondary hyperparathyroidism and scheduled for parathyroidectomy, those who will better benefit from parathyroid scintigraphy.