An atypical lower limb pain revealing a possible systemic venous vasculitis.

We describe a possible systemic vasculitis involving electively large veins. The patient presented with severe febrile lower limb pain. Diagnosis was made by color Doppler ultrasound (CDU) and confirmed by anatomopathological examination of the long saphenous vein, but not by examination of the temporal artery which was normal. CDU found a unilateral halo sign of one temporal artery and a major wall swelling of the lower limb proximal deep veins. The etiology of this possible vasculitis is still unknown. It could be an unusual clinical presentation of giant cell arteritis with vein involvement but without proven arterial involvement. To confirm this hypothesis, it would be interesting to look systematically for lower limb vein thickening with CDU in patients newly diagnosed with giant cell arteritis who have lower limb pain.

Does 18F-FDG PET/CT improve the detection of posttreatment recurrence of head and neck squamous cell carcinoma in patients negative for disease on clinical follow-up?

UNLABELLED: Posttreatment surveillance for the recurrence of head and neck squamous cell carcinoma (HNSCC) is a diagnostic challenge. Tissue distortion from radiation and surgery can obscure early detection of recurrence by conventional follow-up approaches such as physical examination, CT, and MRI. Several studies have shown that 18F-FDG PET may be an effective technique for the detection of persistent, recurrent, and distant metastatic HNSCC after treatment. The aim of this prospective study was to determine the benefits of hybrid 18F-FDG PET/CT in detecting a subclinical locoregional recurrence of HNSCC and distant metastases. The study patients were considered cured of HNSCC on the basis of 12 mo of negative findings on conventional follow-up. We also assessed the diagnostic accuracy of 18F-FDG PET/CT in these patients. METHODS: Ninety-one patients cured of HNSCC without any clinical evidence of recurrence were included. Whole-body 18F-FDG PET/CT examination was performed 11.6+/-4.4 mo after the end of the treatment. The gold standard was histopathology or 6 mo of imaging follow-up. RESULTS: The whole-body 18F-FDG PET/CT examinations had negative results in 52 patients and positive results in 39. Nine of these patients who exhibited abnormal 18F-FDG uptake in the head and neck area did not have recurrent HNSCC (false-positive). Thirty had proven recurrence. The sensitivity and specificity of 18F-FDG PET/CT in this study for the diagnosis of HNSCC recurrence were 100% (30/30) and 85% (52/61), respectively. The positive predictive value was 77% (30/39). The negative predictive value was 100% (52/52). The overall accuracy was 90% (82/91). CONCLUSION: The results of our study confirm the high effectiveness of 18F-FDG PET/CT in the assessment of HNSCC recurrence and suggest that 18F-FDG PET/CT is more accurate than conventional follow-up physical examination alone in the assessment of recurrence after previous curative treatment for HNSCC and could be proposed systematically at 12 mo of the usual follow-up.

Time trend analysis of pulmonary embolism diagnosis with single-photon emission computed tomography ventilation/perfusion imaging.

OBJECTIVE: Following the implementation of single-photon emission computed tomography ventilation/perfusion (SPECT V/Q) in our department, we previously carried out an observational study over the period 2011-2013 that showed the safety of SPECT V/Q to rule out pulmonary embolism (PE). However, PE prevalence (28%) was high compared with some studies. Our hypothesis was that the use of SPECT V/Q may be responsible for an overdiagnosis of PE, especially at the implementation phase of the test. The aim was to carry out a time trend analysis of the evolution over the years of PE diagnosis with SPECT V/Q. PATIENTS AND METHODS: To evaluate the time trend of SPECT V/Q results, the conclusions of all SPECT V/Q scans performed for a suspected acute PE in our department from April 2011 to December 2016 were collected. To confirm the safety of a diagnostic management on the basis of SPECT V/Q to rule out PE, a retrospective observational study of the outcome of patients assessed with SPECT V/Q for suspected acute PE was carried out during the period 2014-2016. SPECT V/Q was interpreted using a diagnostic cutoff of one segmental or two subsegmental mismatches. The final diagnostic conclusion was established by the physician responsible for patient care. The safety of SPECT V/Q was assessed by monitoring the risk of thromboembolic events during the 3-month follow-up period in patients left untreated on the basis of a negative SPECT V/Q. RESULTS: Over the period 2011-2016, an average 16% (95% confidence interval: 10-22%) annual reduction in the proportion of positive SPECT V/Q results was observed. The percentage of positive SPECT V/Q results was 25.3% over the period 2011-2013 compared with 16.3% in 2014-2016 (P<0.0001). Out of the 696 patients analyzed over the period 2014-2016, the SPECT V/Q was positive, indeterminate, and negative in 118, 3, and 575 patients, respectively. The 3-month thromboembolic risk in patients in whom PE was deemed absent according to the SPECT V/Q was 3/543=0.55% (95% confidence interval 0.19-1.61). CONCLUSION: A continuous decrease in the annual proportion of positive SPECT V/Q results was mainly observed while maintaining the safety of the test to rule out PE. Explanatory factors include the introduction of a combined SPECT/CT scan, increased experience and familiarity with the test, and an increased awareness of the risks and consequences of overdiagnosing PE.

Management of suspected pulmonary embolism patients with low clinical and low V/Q probability.

OBJECTIVE: To assess whether guidelines for the management of suspected PE, recommending that ventilation/perfusion (V/Q) scintigraphy should be followed by other imaging in case of non-diagnostic result, and interpreted along with the clinical probability, are applied in daily practice. DESIGN: Two-year audit study. SETTING: Tertiary hospital in France. PARTICIPANTS: All patients referred to the nuclear medicine department for a suspected pulmonary embolism (PE), with a low clinical probability, a positive D-Dimer test, and a low V/Q scintigraphy. INTERVENTION: We reviewed medical records to collect data on further diagnostic strategy and therapeutic management. MAIN OUTCOME MEASURE: Thromboembolic risk during a three-month follow up in patients who did not undergo anticoagulation therapy on the basis of a negative diagnostic work up. RESULTS: Of the 456 selected patients, PE was excluded on the basis of a low pretest probability and a low V/Q scintigraphy probability without further testing in 184 (group 1). In the other 272 patients (group 2), 4 venous thromboembolism (VTE) events were diagnosed by leg vein ultrasonography and/or computed tomography pulmonary angiography. In patients who did not receive anticoagulant treatment during follow up, one patient from group 1 (0.6%, 95% confidence interval 0.1 to 3.3) and two patients from group 2 (0.9%, 95% CI 0.2 to 3.2) had an acute venous thromboembolic event. CONCLUSION: Different attitudes are adopted by physicians in patients with a low clinical probability and a low V/Q scintigraphy probability, without impact on safety, as assessed by a non-significant difference in the three-month thromboembolic risks between these two groups.

A new SPECT/CT reconstruction algorithm: reliability and accuracy in clinical routine for non-oncologic bone diseases.

BACKGROUND: xSPECT Bone® (xB) is a new reconstruction algorithm developed by Siemens® in bone hybrid imaging (SPECT/CT). A CT-based tissue segmentation is incorporated into SPECT reconstruction to provide SPECT images with bone anatomy appearance. The objectives of this study were to assess xB/CT reconstruction diagnostic reliability and accuracy in comparison with Flash 3D® (F3D)/CT in clinical routine. Two hundred thirteen consecutive patients referred to the Brest Nuclear Medicine Department for non-oncological bone diseases were evaluated retrospectively. Two hundred seven SPECT/CT were included. All SPECT/CT were independently interpreted by two nuclear medicine physicians (a junior and a senior expert) with xB/CT then with F3D/CT three months later. Inter-observer agreement (IOA) and diagnostic confidence were determined using McNemar test, and unweighted Kappa coefficient. The study objectives were then re-assessed for validation through > 18 months of clinical and paraclinical follow-up. RESULTS: No statistically significant differences between IOA xB and IOA F3D were found (p = 0.532). Agreement for xB after categorical classification of the diagnoses was high (κ xB = 0.89 [95% CI 0.84 -0.93]) but without statistically significant difference F3D (κ F3D = 0.90 [95% CI 0.86 - 0.94]). Thirty-one (14.9%) inter-reconstruction diagnostic discrepancies were observed of which 21 (10.1%) were classified as major. The follow-up confirmed the diagnosis of F3D in 10 cases, xB in 6 cases and was non-contributory in 5 cases. CONCLUSIONS: xB reconstruction algorithm was found reliable, providing high interobserver agreement and similar diagnostic confidence to F3D reconstruction in clinical routine.

Feasibility of Systematic Respiratory-Gated Acquisition in Unselected Patients Referred for 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography.

OBJECTIVE: Respiratory motion in 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) induces blurred images, leading to errors in location and quantification for lung and abdominal lesions. Various methods have been developed to correct for these artifacts, and most of current PET/CT scanners are equipped with a respiratory gating system. However, they are not routinely performed because their use is time-consuming. The aim of this study is to assess the feasibility and quantitative impact of a systematic respiratory-gated acquisition in unselected patients referred for FDG PET/CT, without increasing acquisition time. METHODS: Patients referred for a FDG PET/CT examination to the nuclear medicine department of Brest University Hospital were consecutively enrolled, during a 3-month period. Cases presenting lung or liver uptakes were analyzed. Two sets of images were reconstructed from data recorded during a unique acquisition with a continuous table speed of 1 mm/s of the used Biograph mCT Flow PET/CT scanner: standard free-breathing images, and respiratory-gated images. Lesion location and quantitative parameters were recorded and compared. RESULTS: From October 1 2015 to December 31 2015, 847 patients were referred for FDG PET/CT, 741 underwent a respiratory-gated acquisition. Out of them, 213 (29%) had one or more lung or liver uptake but 82 (38%) had no usable respiratory-gated signal. Accordingly, 131 (62%) patients with 183 lung or liver uptakes were analyzed. Considering the 183 lesions, 140 and 43 were located in the lungs and the liver, respectively. The median (IQR) difference between respiratory-gated images and non-gated images was 18% (4-32) for SUVmax, increasing to 30% (14-57) in lower lobes for lung lesions, and -18% (-40 to -4) for MTV (p < 0.05). Technologists' active personal dosimetry and mean total examinations duration were not statistically different between periods with and without respiratory gating. CONCLUSION: This study showed that a systematic respiratory-gated acquisition without increasing acquisition time is feasible in a daily routine and results in a significant impact on PET quantification. However, clinical impact on patient management remains to be determined.

Incremental diagnostic utility of systematic double-bed SPECT/CT for bone scintigraphy in initial staging of cancer patients.

BACKGROUND: SPECT/CT has been shown to increase the diagnostic performance of bone scintigraphy for staging of malignancies. A systematic double-bed SPECT/CT of the trunk may allow further improvement. However, this would be balanced by higher dosimetry and longer acquisition time. The objective was to assess the incremental diagnostic utility of a systematic double-bed SPECT/CT acquisition for bone scintigraphy in initial staging of cancer patients, especially compared with the usual approach consisting in a whole body planar scan (WBS) plus one single-bed targeted SPECT/CT. METHODS: One hundred two consecutive patients referred for bone scintigraphy for initial staging of malignancy were analyzed. All patients underwent a double-bed SPECT/CT acquisition of the trunk. Images were interpreted by two nuclear medicine physicians in a 3-step procedure. Firstly, only WBS planar images were used; secondly, one additional single-bed SPECT/CT chosen based on planar images was used; finally, WBS planar and double-bed SPECT/CT images were interpreted. Lesions were classified as benign, equivocal or suspicious for metastasis. A per-lesion, per-anatomical region and per-patient analysis was performed. RESULTS: In a per-lesion analysis, the number of equivocal and suspicious lesions was 91 and 241 using WBS planar images, 17 and 259 using a single-bed SPECT/CT acquisition and 11 and 269 using double-bed SPECT/CT images, respectively. In a per-patient analysis, the diagnostic conclusion was negative, equivocal or suspicious for malignancy in 35, 53 and 14 patients using WB planar images, 77, 6 and 19 patients using an additional single-bed SPECT/CT and 76, 7 and 19 using double-bed SPECT/CT images, respectively. Seventeen lesions unseen on WBS images were interpreted as suspicious (n = 12) or equivocal (n = 5) on double-bed SPECT/CT images. Six lesions unseen on "WBS + targeted single-bed SPECT/CT" were interpreted as suspicious on double-bed SPECT/CT, with no shift in the metastatic status of patients. CONCLUSION: A systematic double-bed SPECT/CT acquisition has a limited incremental diagnostic value over an oriented single-bed SPECT/CT in terms of specificity and conclusiveness of bone scintigraphy in the initial staging of cancer patients. However, it slightly improved the sensitivity of the test by detecting unseen lesions on WBS, which may be of value for initial staging of cancer.

99mTc ovalbumin labelled eggs for gastric emptying scintigraphy: in-vitro comparison of solid food markers.

BACKGROUND: The reliability of solid phase gastric emptying measurements by scintigraphy requires a marker that remains within the solid component of the test meal, and which is not degraded by the gastric juice throughout the scintigraphic procedure. In Europe, foods are most often labelled with 99mTc rhenium sulfide macrocolloid (RSMC) but this solid phase marker was withdrawn from the market in January 2004. OBJECTIVE: To test other potential solid phase markers and to compare them to the reference marker RSMC. These markers were rhenium sulfide nanocolloid (RSNC), tin fluoride colloid (TFC), phytates and two albumins (Alb and AlbC). All were radiolabelled with 99mTc. METHODS: After quality control, each 99mTc marker was incorporated into the albumin of one egg. Then, egg white and yolk were mixed together, and a well-cooked omelette was prepared. Aliquots of the omelette were incubated with an acidic solution of pepsin at 37 degrees C which mimicked gastric juice. Unbound radioactivity in the supernatant fraction was measured at various times up to 3 h. RESULTS: The radiochemical purity was > 95% for all radiopharmaceuticals. During the in-vitro incubation, the percentage of 99mTc labelled colloids released from the omelette increased continuously: after 3 h, 5% for TFC and RSMC, 8% for phytates, and > 9% for the two albumins and RSNC. CONCLUSION: Considering quality controls and release of 99mTc during in-vitro incubation of the omelette, TFC showed the same behaviour as the reference marker RSMC. Thus, TFC seems to be the best candidate to replace RSMC for the radiolabelling of the solid phase of the gastric emptying test meal.

Interest of chest X-ray in tailoring the diagnostic strategy in patients with suspected pulmonary embolism.

Current diagnostic strategies for pulmonary embolism rely on the sequential use of noninvasive diagnostic tests including ventilation-perfusion (V/Q) scan and computed tomography pulmonary angiography (CTPA). V/Q scan remains criticized because of a high proportion of nondiagnostic test results, especially when the chest X-ray (CXR) is abnormal. The present study assesses whether CXR results have an impact on the conclusiveness of a noninvasive diagnostic strategy of pulmonary embolism based on the combination of pretest probability, compression ultrasonography, V/Q scan, and CTPA. Patients suspected of having pulmonary embolism were managed according to a validated diagnostic strategy. All patients underwent a CXR within 24 h of the suspicion of pulmonary embolism. CXR results were correlated to strategy conclusiveness, as assessed by the rate of required CTPA as per the diagnostic algorithm. Two hundred and twenty-three patients were retrospectively analyzed. CXRs were considered as normal in 108 (48%) patients and abnormal in 115 (52%) patients. According to the diagnostic algorithm, a CTPA was required to reach a diagnostic conclusion in 11 (10%) patients of the normal CXR group, and in 14 (12%) patients of the abnormal CXR group (P > 0.05). In this study, the presence of CXR abnormalities did not have an impact on the conclusiveness of a diagnostic strategy of pulmonary embolism based on V/Q scan. CXR abnormalities should likely not be regarded as a contraindication to the use of V/Q scan in patients with suspected pulmonary embolism.

Octreotide imaging plus bone scintigrams to optimally localize gastroenteropancreatic neuroendocrine tumors.

PURPOSE: In-111 pentetreotide (Octreotide) is highly sensitive for detecting gastroenteropancreatic neuroendocrine tumors and their metastases. However, a lack of landmarks makes it difficult to localize them anatomically. To overcome this difficulty, the authors simultaneously obtained Octreotide and bone tomoscintigrams, in addition to standard planar images. They used a bicolor scale to display pairs of scintigrams to easily identify the distribution of both tracers. METHODS: Twenty-one hours after Octreotide injection, Tc-99m MDP was also administered to the patients. Three hours later, dual-energy planar and tomographic data were acquired simultaneously. The latter were reconstructed using a filtered back-projection algorithm using a Metz filter. Both sets of data were displayed simultaneously using a bicolor scale, such that Octreotide data appear in green and bone data in red. RESULTS: Planar, tomographic, and three-dimensional data were obtained. With this approach, foci of abnormal uptake are localized more precisely. Hard data can be transmitted easily to referring physicians, who appreciate this compact and efficient means to locate foci of abnormal uptake, especially during surgery planning. However, this method is not well suited to the visualization of small lesions with low Octreotide uptake because the intensity range is drastically reduced. Such lesions are better seen on Octreotide planar images and standard tomoscintigrams. CONCLUSIONS: This approach, which involves only standard image processing, provides landmarks to easily localize significant Octreotide uptake. It can be implemented readily in most nuclear medicine workstations. It complements but does not replace the usual method to display Octreotide data.

Role of SPECT/CT compared with MRI in the diagnosis and management of patients with wrist trauma occult fractures.

BACKGROUND: The diagnosis of wrist fractures, especially scaphoid fractures, remains a challenge because of nonunion risk. Currently, new hybrid technologies are emerging such as 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. METHODS: In this study, all patients addressed at the orthopedic department at Brest University Hospital for wrist pain after trauma with initial normal plain radiographs were prospectively included. Patients with normal radiographs but with signs strongly suggestive 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 up for at least 6 months and reviewed by the same surgeon. SPECT/CT findings were compared with those of the other modalities and follow-up. RESULTS: From December 2009 to May 2011, 57 patients were enrolled. Fifty-seven SPECT/CT and 52 MRI scans were obtained. Twenty-eight patients had normal imaging results, whereas 29 patients presented bone bruise and/or fractures. Ten patients were concordant according to SPECT/CT and MRI; 2 patients presented fractures on SPECT/CT without MRI performed; 17 patients had partially discordant results. Only 1 patient presented a nonunion at the follow-up, whereas both investigations were positive. CONCLUSIONS: This study highlights the good performances of SPECT/CT, which allows the detection of most occult carpal fractures. When a carpal occult fracture is strongly suspected clinically, SPECT/CT might be proposed at first intention after normal radiographs.

V/Q SPECT interpretation for pulmonary embolism diagnosis: which criteria to use?

UNLABELLED: Ventilation-perfusion (V/Q) SPECT has been reported to improve the diagnostic performance of V/Q imaging for the diagnosis of pulmonary embolism (PE). However, only sparse data based on an objective reference test are available, and the criteria used for interpretation have varied widely. Therefore, the aim of our study was to assess the performance of V/Q SPECT using various criteria for interpretation, in comparison with a validated independent diagnostic strategy. METHODS: The SPECT study included patients for whom V/Q SPECT data were compared with the results of an independent and validated diagnostic algorithm for PE. V/Q SPECT scans were performed after intravenous injection of (99m)Tc-macroaggregated albumin and simultaneous ventilation with (81m)Kr gas. Interpretation was performed independently by 2 nuclear medicine physicians who were not aware of the clinical history, diagnostic strategy conclusion, or patient's outcome. Sensitivity, specificity, and likelihood ratios were evaluated for various combinations of mismatched defect numbers and sizes (segmental or subsegmental). Generation of receiver-operating-characteristic curves was based on the number of mismatch defects and the number of subsegmental mismatch defects or equivalent. RESULTS: Of the 249 patients who were analyzed, the diagnosis of PE was confirmed in 49 and ruled out in 200 according to the previously validated independent strategy. Of all the tested criteria, the best performance was achieved using a diagnostic cutoff of at least 1 segmental or 2 subsegmental mismatches, with sensitivity and specificity of 0.92 (95% confidence interval, 0.84-1) and 0.91 (95% confidence interval, 0.87-0.95), respectively. With a negative V/Q SPECT result, the posttest probability of PE was 0.010, 0.037, and 0.119 for a low, intermediate, and high clinical probability. With a positive V/Q SPECT result, the posttest probability of PE was 0.531, 0.814, and 0.939 for a low, intermediate, and high probability. CONCLUSION: For V/Q SPECT interpretation, a diagnostic cutoff of 1 segmental or 2 subsegmental mismatches seems best for confirming or excluding acute PE.

Prognostic value of fluorine-18 fluorodeoxyglucose positron-emission tomography imaging in patients with head and neck squamous cell carcinoma.

BACKGROUND: High tumor uptake of fluorodeoxyglucose (FDG) is associated with an unfavorable outcome in patients with cancer. We evaluated FDG uptake as a prognostic factor in patients with head and neck squamous cell carcinoma. METHODS: Maximum standardized uptake values (SUVmax) of tumor, liver, and pulmonary artery were recorded. Ratios of SUVmax from tumor to liver (T/L) and from tumor to pulmonary artery (T/PA) were calculated for each patient. Clinical data, tumor, and SUVmax ratios were compared with disease-free survival (DFS) and overall survival (OS). RESULTS: Eighty-nine patients were included: 48 presented a local recurrent disease or distant metastases and 42 died. For both DFS and OS, tumor SUVmax value of 7 was the best cutoff value and 4 and 5 for T/L and T/PA ratios. Multivariate analysis confirmed the independent prognostic value of these 3 thresholds for DFS and OS. CONCLUSIONS: FDG uptake has a significant and independent relationship with recurrence and survival.

Diagnostic accuracy of single-photon emission tomography ventilation/perfusion lung scan in the diagnosis of pulmonary embolism.

BACKGROUND: Planar ventilation/perfusion (V/Q) lung scintigraphy is a validated tool for the diagnosis of pulmonary embolism (PE). Nevertheless, given the high rate of nonconclusive V/Q, further investigation is often necessary. V/Q single-photon emission CT (SPECT) scan could improve V/Q performance, but sparse data are available on its accuracy. This study assessed the diagnostic performance of V/Q SPECT scan in a cohort of consecutive patients with suspected PE. METHODS: Three hundred twenty-one consecutive patients with a clinical suspicion of PE were prospectively included. Patients suspected of having PE were managed according to a reference diagnostic strategy validated by a 3-month follow-up. In addition to the reference strategy, patients had a V/Q SPECT scan, the results of which were compared with the initial work-up results. RESULTS: Prevalence of PE was 0 of 41 (0%; 95% CI, 0%-9%), six of 134 (4%; 95% CI, 2%-9%),15 of 36 (42%; 95% CI, 27%-58%), and 28 of 32 (88%; 95% CI, 72%-95%) in the normal, low,intermediate, and high V/Q SPECT scan probability groups, respectively. The combination of V/Q SPECT scan with clinical probability was diagnostic in 88% of patients. CONCLUSIONS: V/Q SPECT scan results show satisfactory accuracy for PE diagnosis. Validation of dedicated interpretation criteria is required, followed by outcome studies that use V/Q SPECT scan as part of a diagnostic strategy to rule out PE. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT01183026; URL: www.clinicaltrials.gov

Noninvasive diagnosis of pulmonary embolism.

BACKGROUND: We designed a simple and integrated diagnostic algorithm for acute pulmonary embolism (PE). Diagnosis was based on clinical probability assessment, plasma D-dimer testing, then sequential testing to include lower limb venous compression ultrasonography, ventilation perfusion lung scan, and chest multidetector CT (MDCT) imaging. METHODS: We included 321 consecutive patients presenting at Brest University Hospital in Brest, France, with clinically suspected PE and positive d-dimer or high clinical probability. Patients in whom VTE was deemed absent were not given anticoagulants and were followed up for 3 months. RESULTS: Detection of DVT by ultrasonography established the diagnosis of PE in 43 (13%). Lung scan associated with clinical probability was diagnostic in 243 (76%) of the remaining patients. MDCT scan was required in only 35 (11%) of the patients. The 3-month thromboembolic risk in patients not given anticoagulants, based on the results of the diagnostic protocol, was 0.53% (95% CI, 0.09-2.94). CONCLUSIONS: A diagnostic strategy combining clinical assessment, d-dimer, ultrasonography, and lung scan gave a noninvasive diagnosis in the majority of outpatients with suspected PE and appeared to be safe.

Clinical and therapeutic impact of 18F-FDG PET/CT whole-body acquisition including lower limbs in patients with malignant melanoma.

OBJECTIVES: To assess the added benefit of scanning lower limbs in addition to the usual whole-body positron emission tomography/computed tomography (PET/CT) scan in patients with no known or suspected primary or metastatic melanoma involving the lower limbs. MATERIALS AND METHODS: This is a retrospective study of 122 consecutive patients [174 2-[¹8F]-fluoro-2-deoxy-D-glucose (FDG) PET/CT] who underwent FDG PET/CT for staging of melanoma at different time points in the course of the disease from October 2005 to February 2009 at the Brest University Hospital. Reports of whole-body PET/CT scans including lower limbs were reviewed. PET/CT abnormalities on the lower extremities were tabulated by location and correlated with pathology, other imaging studies and at least a 6-month clinical follow-up. The usefulness of lower limbs acquisition in clinical management was evaluated according to imagery findings. RESULTS: Among the 174 consecutive PET/CT scans performed in 122 patients, 33 scans in 28 patients highlighted abnormal FDG uptakes considered as equivocal or suggestive of malignancy in the lower limbs. In 28 cases, uptakes were located at once in the lower limbs and in the rest of the body (lung, liver, mediastinal and sub-diaphragmatic lymph nodes, adrenal glands, bone) corresponding to disseminated disease. In five cases, PET/CT uptakes were located only in lower limbs; each pathological uptake corresponded to benign lesions. Lower limbs findings never impacted clinical and therapeutic decision. CONCLUSION: Lower limbs additional PET/CT acquisition seems to offer poor additional benefit with none unexpected lesion detected and routine skull base to upper thigh images might be sufficient for this subset of patients.

Detection of occult wrist fractures by quantitative radioscintigraphy: a prospective study on selected patients.

OBJECTIVE: To determine the value of quantitative radioscintigraphy (QRS) in the diagnosis of wrist trauma occult fractures. PURPOSE: Because of the risk of non-union, the diagnosis of wrist fractures, including scaphoid fractures, is essential but remains difficult despite many imaging modalities. The aim of the study was to assess the benefits of QRS in the diagnosis of occult post-trauma wrist fractures. METHODS: This prospective study included all patients presenting at the orthopaedic department at Brest University Hospital for wrist pain after trauma with initial normal plain radiographs. Patients with normal radiographs but strongly suspected of fracture underwent QRS consisting of three-phase bone scintigraphy with quantitative analysis. When a fracture was suspected the radiograph and scintigraphy were fused to precisely locate the fracture if the index was higher than 2. If the index was lower than 1.9, fracture was excluded. Between these two indices, other investigations, such as magnetic resonance imaging, were performed. All patients were followed for at least 3 months and reviewed by the same surgeon. Patients underwent a physical examination and possibly other investigations. RESULTS: From April 2006 to July 2008, 87 patients were enrolled (34 women, 53 men; median age 29 years; range, 15-87 years). Among the 46 pathologic bone scintigrams, 55 occult fractures were highlighted. At follow-up, none presented non-union. One had an undetermined QRS. Among the 40 negative results for QRS at follow-up, only one had a non-union. Sensitivity and negative predictive value were 97 and 98%, respectively for carpal fractures. CONCLUSION: This study highlights the benefit of QRS, which allows the detection of most occult carpal fractures and reduces the risks of complications such as pseudoarthritis.