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1.
Positron emission tomography (PET), invented over 25 years ago, is the only imaging technique that provides images of the biological basis of disease. Since disease is a biological process, PET routinely detects disease when other imaging studies, such as CT and MRI, are normal. In addition to its clinical effectiveness, PET has been shown to reduce costs, primarily due to the elimination of other less accurate diagnostic tests and ineffective surgeries. PET has been determined to be applicable to a number of specific applications in the areas of: imaging cancer patients, characterizing myocardial blood flow and viability, and brain imaging in various physiological and pathologic conditions. Tremendous progress has been made in resolving the regulatory and reimbursement issues facing the field of PET. Working with HCFA, representatives of the Institute for Clinical PET and the Society of Nuclear Medicine have brought about expanded HCFA coverage for PET. When HCFA first authorized payment for PET, all coverage decisions were restricted to HCFA and an expanded national coverage policy. HCFA revised its national coverage policy in 1997; this was the first of several steps taken by HCFA towards careful expansion of PET reimbursement. In March 1999, three new indications for whole-body PET scans were added to Medicare's coverage policy. The Institute for Clinical PET is continuing to work with HCFA on continued, appropriate expansion of the coverage policy. This article is partially excerpted from a written statement made by Terry Douglass, Ph.D., president of CTI, Inc., on May 12, 1999, before the Senate Committee on Commerce, Science and Transportation and its Subcommittee on Science, Technology and Space. This was part of the committee's study of "Emerging Technologies in the New Millennium."  相似文献   

2.
Lymph node metastases: CT and MRI   总被引:10,自引:0,他引:10  
Imaging is playing a major role in the assessment of cervical lymphadenopathy. In head and neck malignancies, imaging can be helpful for staging, and sometimes in differentiating different types of metastases, such as squamous cell carcinomas, non-hodgkins disease and thyroid carcinomas. This article on imaging of cervical lymph node metastases will describe both radiological and clinical aspects. Computed tomography (CT) and magnetic resonance (MR) are widely used for primary tumor and nodal imaging. However, very seldom these modalities have clinical consequences for the management of the neck, such as a wait-and-see policy if no nodes are depicted. This is caused by the limited accuracy of both modalities caused by the fallibility of radiologic criteria for metastases. Ultrasound (US) is hampered by similar morphologic criteria, and only US-guided fine needle aspiration cytology (FNAC) can offer additional cytologic criteria which are more reliable.  相似文献   

3.
AIM: The purpose of this study was twofold: first to provide data for more accurate counselling of parents with regard to prognosis, and second, to ensure that by following a policy of selective micturating cystourethography (MCUG), significant pathology is not missed, in particular vesicoureteric reflux (VUR). (MCUG is only undertaken if the renal pelvic diameter (RPD) is >/= 10 mm or if there is calyceal or ureteric dilatation.) MATERIAL AND METHODS: Data were collected prospectively over a 6-year period. Pre and postnatal imaging findings were collected for all infants in whom a RPD of >/= 5 mm was identified at any gestational age. The imaging records of all patients were reviewed in 2005 for evidence of pathology detected after re-presentation with symptoms. The age range at review varied from 2-8 years. RESULTS: Complete data were available in 527 infants. The risk of significant pathology was related to the degree of antenatal renal pelvic dilatation varying from 6% for a RPD of 5 mm at 20 weeks gestation to 38% at 10 mm. At 28-33 weeks gestation the risk varied from 5% at 5mm to 15% at 10 mm. Subsequent imaging record review revealed only one patient with grade II VUR in the study population not picked up by our selective MCUG policy. CONCLUSION: The present study provides prognostic information that can be given to parents both antenatally and postnatally, and reassurance that a selective MCUG policy is appropriate.  相似文献   

4.
MR imaging evaluation of the activity of Crohn's disease.   总被引:14,自引:0,他引:14  
OBJECTIVE: The purpose of this study was to evaluate the sensitivity and specificity of MR imaging in assessing the activity of Crohn's disease. SUBJECTS AND METHODS: Thirty symptomatic patients with Crohn's disease but uncertain disease activity were prospectively examined using MR imaging. Twenty-nine patients were scored using the Crohn's disease activity index. Six hundred milliliters of water orally and 1 mg of glucagon intramuscularly were given before imaging. Breath-hold images were obtained using T2-weighted turbo spin-echo, T1-weighted fast low-angle shot, and fat-suppressed gadolinium-enhanced T1-weighted fast low-angle shot sequences. Images were assessed by two radiologists who were unaware of the patient's symptoms, clinical scoring, and other imaging tests, and who reached a consensus about the imaging findings (bowel wall thickening, bowel wall enhancement, and perienteric changes) and determined the absence or presence of active disease in each patient. MR imaging findings were correlated with endoscopy and surgery. RESULTS: Twenty-three patients had active disease and seven patients had inactive disease. One hundred twenty-four of a total of 168 bowel segments were examined with both MR imaging and endoscopy or surgery. On a per patient basis, MR imaging had an overall sensitivity of 91% and a specificity of 71% for active disease. The Crohn's disease activity index had a sensitivity of 92% and a specificity of 28%. On a per segment basis, MR imaging had a sensitivity of 59% and a specificity of 93%. Bowel wall thickening of greater than 4 mm, bowel wall enhancement (ratio of signal intensity of abnormal to normal bowel > 1.3:1), and increased mesenteric vascularity were useful in identifying active disease. A layered enhancement pattern after the IV administration of gadolinium was highly specific for active inflammation. CONCLUSION: MR imaging is useful in assessing the activity of Crohn's disease and may be helpful when clinical scoring is equivocal.  相似文献   

5.
AIM: to determine the effectiveness of a new imaging algorithm in the investigation of suspected pulmonary embolism (PE). MATERIALS AND METHODS: A new imaging algorithm for suspected PE was introduced following the installation of a multisection computed tomography (CT) machine at our institution. Before its installation, patients with suspected PE were evaluated with ventilation/perfusion (V/Q) scintigraphy. Subsequently, patients were triaged according to chest radiography (CR) and respiratory history to either lung scintigraphy or CT pulmonary angiography (CTPA). Patients with a normal CR and no history of lung disease were evaluated using perfusion (Q) scintigraphy [ventilation (V) scintigraphy was no longer performed]. Patients with an abnormal CR, asthma or chronic lung disease were evaluated using CTPA. All V/Q images in a continuous 3-year period before the introduction of the new imaging algorithm and all Q images performed in a 3-year period after its introduction were retrospectively reviewed. Imaging reports were categorized into normal, non-diagnostic (low or intermediate probability) or high probability for PE. Patients in the later group who subsequently underwent CTPA, were also reviewed. RESULTS: After the policy change the percentage of normal scintigrams significantly increased (39 to 60%; p<0.001). There was a non-significant increase in the percentage of high probability scintigrams (15 to 18%; p=0.716). Overall the diagnostic yield of lung scintigraphy improved significantly (54 to 78%; p<0.001). CONCLUSION: the diagnostic performance of lung scintigraphy can be improved by careful triage of patients to either Q scintigraphy or CTPA based on clinical history and CR findings. Q scintigraphy remains a valuable diagnostic test in the investigation of suspected PE in carefully selected patients.  相似文献   

6.
Technetium-99m 2-methoxyisobutylisonitrile (99mTc-MIBI) is a lipophilic agent that has been proposed as a useful tracer for the detection of disease sites in patients with multiple myeloma (MM). We performed a prospective study to determine the potential of 99mTc-MIBI imaging for the evaluation of the extent of primary disease in patients with advanced stage MM, compared with skeletal survey and bone scintigraphy. Twenty patients with advanced stage MM at initial diagnosis underwent whole-body 99mTc-MIBI imaging, together with contemporaneous skeletal survey and bone scintigraphy. The findings of 99mTc-MIBI imaging were correlated with the results of skeletal survey and bone scan. All 99mTc-MIBI scans were positive for the presence of active MM, whereas skeletal surveys were positive in 18 patients (90%) with osteolytic lesions. Bone scintigraphy demonstrated MM in only 15 patients (75%). In two patients with no detectable lesions on skeletal survey, 99mTc-MIBI imaging revealed uptake in the spine, corresponding to the abnormalities seen on magnetic resonance imaging (MRI). With respect to the localization of bone lesions, 99mTc-MIBI imaging was superior to bone scintigraphy in 15 patients (75%) and had concordant results with bone scintigraphy in four (20%). 99mTc-MIBI imaging is a very sensitive imaging modality for the identification of the extent of disease in patients with advanced MM. It is clearly superior to bone scintigraphy and complements the results of skeletal survey by finding additional disease sites. Hence, in active MM patients, 99mTc-MIBI imaging has the potential to detect bone marrow disease that cannot be detected by skeletal survey and bone scintigraphy.  相似文献   

7.
PURPOSE: This study was done to determine the diagnostic accuracy of magnetic resonance (MR) imaging in patients with rectal carcinoma by comparing post-chemoradiation MR imaging with pathological specimens. MATERIALS AND METHODS: We enrolled 39 patients with locally advanced rectal cancer. All patients received chemoradiation therapy before surgery and neoadjuvant chemoradiation therapy followed by MR imaging. MR images were analysed by a team of two expert radiologists unaware of the clinical and histopathological findings. RESULTS: Following neoadjuvant chemoradiation therapy, the analysis of MR images showed 23 (59%) patients with a rectal disease staged ≤T2 and 16 (41%) with a disease staged >T2. Post-treatment histological staging (TNM) revealed 13 patients with a disease >T2 and 26 patients with a disease ≤T2. Cohen's kappa to measure concordance between post-chemoradiation MR staging and histological response showed 83.6% concordance for disease confined to the serosa (≤T3): concordance was 97.22% for disease ≤N1 and 33.33% for disease >N1. CONCLUSIONS: MR imaging is critical for discovering T3 disease; moreover, morphological MR imaging does not always provide the opportunity to discern small residual cancer cells hidden in fibrotic tissue that could cause involvement of circumferential resection margin (CRM) on histology.  相似文献   

8.
PURPOSE: To examine whether choline measurement by proton magnetic resonance (MR) spectroscopy in patients with malignant tumors is clinically meaningful in addition to routine MR imaging. MATERIALS AND METHODS: MR spectroscopy and MR imaging were performed in 27 consecutive patients with suspected malignant disease. Malignancy was assessed based on total choline compound levels using proton MR spectroscopy, and the results were compared with MR imaging findings. RESULTS: The sensitivity of MR imaging (84%, 21/25) was not significantly different from that of MR spectroscopy (88%, 22/25) among the 25 actual malignant diseases. Both MR imaging and MR spectroscopy produced two false-negative results. In one case, MR spectroscopy produced a false-negative result, whereas MR imaging produced a true-positive result. In two cases of benign breast disease, MR imaging produced false-positive results. MR spectroscopy produced one true-negative result and one false-positive result. CONCLUSION: Although choline measurement by MR spectroscopy is a useful tool in the evaluation of malignant disease, it should be reserved for patients with suspected malignant disease that cannot be detected by MR imaging, such as those with non-palpable prostate tumor with elevated sPSA levels.  相似文献   

9.
BACKGROUND AND PURPOSE: In cases of metastatic disease of the spine, monitoring the response to medical therapy with plain radiography, bone scanning, and conventional spin-echo sequence MR imaging is unsatisfactory because of the insensitivity or nonspecific findings of these imaging modalities. The purpose of this study was to investigate signal intensity changes of bone marrow after therapy by using diffusion-weighted MR imaging to monitor the response to medical therapy in cases of metastatic disease of the spine. METHODS: Twenty-four patients with metastatic disease of the spine were examined with MR imaging. Diffusion-weighted MR imaging and spin-echo MR imaging were performed in all patients before and after radiation therapy. Follow-up diffusion-weighted MR imaging and spin-echo MR imaging were performed for comparison purposes in nine cases at 1 month, in seven cases at 2 months, in seven cases at 3 months, and in three cases at 6 months after therapy. The diffusion-weighted MR imaging sequences were based on a steady-state free precession with a low b value (165 s/mm(2)) and a single shot stimulated echo-acquisition mode with a high b value (650 s/mm(2)). Apparent diffusion coefficient maps were obtained using two different b values incorporated in a diffusion-weighted single shot stimulated echo-acquisition mode sequence. Apparent diffusion coefficient maps were obtained in three cases. Signal intensity changes of the metastatic disease of the vertebral bone marrow before and after therapy on conventional spin-echo sequence and diffusion-weighted MR images were evaluated. RESULTS: As shown by diffusion-weighted MR imaging, metastatic disease of the vertebral bone marrow included in our study before therapy was hyperintense to normal vertebral bodies. In 23 patients with clinical improvement, metastatic disease of the spine after therapy was hypointense relative to normal vertebral bodies on the follow-up diffusion-weighted MR images. In one patient with hepatocellular carcinoma, the clinical symptoms did not improve and follow-up bone scanning performed 6 months after therapy showed increased uptake. Persistent hyperintense bone marrow after therapy was also noted on diffusion-weighted MR images. Decreased signal intensity of the metastatic disease of the spine on diffusion-weighted MR images was observed >1 month after therapy. CONCLUSION: Diffusion-weighted MR imaging shows that, with successful therapy, there is decreased signal intensity of metastatic disease of the vertebral bone marrow.  相似文献   

10.
PurposeLiterature reports indicate that advanced imaging is overutilized, especially in the emergency setting. At our institution, stat spinal MRI for suspected acute spinal cord compression (ASCC) was perceived to be excessively utilized. A continuous quality improvement process was employed to investigate this trend and improve the efficiency of this diagnosis.MethodsSpine imaging in patients with suspected ASCC was retrospectively evaluated for appropriateness of indications and quality of imaging. Based on the results, a new institutional policy for ordering MR for suspected ASCC was implemented, concurrent with development of a new screening spine MRI protocol. Subsequently, indications, efficacy, and imaging utilization of the new strategy were analyzed for improved operational effectiveness.ResultsThe initial retrospective study demonstrated only a 1.4% positive rate of ASCC as well as image-quality degradation due to patient motion resulting from prolonged scan times. Based on these results, a new institutional policy for ordering stat ASCC spine MRI was instituted with an updated screening MRI protocol. This policy resulted in a positive rate of ASCC of 4.4%, and decreased scan time by 50%-70%, while preserving diagnostic image quality and decreasing resource utilization.ConclusionsAs suspected, stat spinal MRI for ASCC was excessively utilized at our institution. The study demonstrated that systemic improvements regarding this issue can be achieved by using a multidisciplinary approach and following a continuous quality improvement methodology. A new MRI protocol for identification of ASCC was found to preserve image quality and diagnostic confidence, while simultaneously decreasing scan time and use of valuable health care resources.  相似文献   

11.
PurposeThe operational and financial impact of the widespread coronavirus disease 2019 (COVID-19) curtailment of imaging services on radiology practices is unknown. We aimed to characterize recent COVID-19-related community practice noninvasive diagnostic imaging professional work declines.MethodsUsing imaging metadata from nine community radiology practices across the United States between January 2019 and May 2020, we mapped work relative value unit (wRVU)-weighted stand-alone noninvasive diagnostic imaging service codes to both modality and body region. Weekly 2020 versus 2019 wRVU changes were analyzed by modality, body region, and site of service. Practice share χ2 testing was performed.ResultsAggregate weekly wRVUs ranged from a high of 120,450 (February 2020) to a low of 55,188 (April 2020). During that −52% wRVU nadir, outpatient declines were greatest (−66%). All practices followed similar aggregate trends in the distribution of wRVUs between each 2020 versus 2019 week (P = .96-.98). As a percentage of total all-practice wRVUs, declines in CT (20,046 of 63,992; 31%) and radiography and fluoroscopy (19,196; 30%) were greatest. By body region, declines in abdomen and pelvis (16,203; 25%) and breast (12,032; 19%) imaging were greatest. Mammography (−17%) and abdominal and pelvic CT (−14%) accounted for the largest shares of total all-practice wRVU reductions. Across modality-region groups, declines were far greatest for mammography (−92%).ConclusionsSubstantial COVID-19-related diagnostic imaging work declines were similar across community practices and disproportionately impacted mammography. Decline patterns could facilitate pandemic second wave planning. Overall implications for practice workflows, practice finances, patient access, and payment policy are manifold.  相似文献   

12.
笔者报道了1例肋骨血管瘤患者,即从临床症状、影像学表现、临床诊断、组织病理学检查诊断及预后等方面介绍并分析了该病的特点,并通过文献复习加深了对肋骨血管瘤的认识。该病为肋骨的血管瘤病变,其进展相对较缓慢,虽然在影像学上无明显的特异性表现,但并非只能通过组织病理学检查诊断,影像学表现在该病的诊断上仍有一定的参考价值。该病的影像学表现多种多样,易与恶性骨肿瘤及骨肿瘤样病变混淆。因该病极易误诊,所以需结合临床表现、影像学检查及术后组织病理学检查综合考虑。  相似文献   

13.
MR imaging in the differential diagnosis of scrotal and testicular disease   总被引:1,自引:0,他引:1  
It is frequently impossible to discriminate between various causes of scrotal pain and swelling by means of clinical examination and ultrasound (US) alone. Surgical exploration is necessary in cases of indefinite differential diagnosis. For evaluation of the diagnostic potential of magnetic resonance (MR) imaging in scrotal disease, 200 patients with testicular abnormalities were studied. For 74 of these patients, the diagnosis was cancer, based on clinical and US findings. MR imaging demonstrated malignant disease in 54 patients and benign disease in 20. All of the MR imaging findings were confirmed at surgical biopsy. Despite high costs of the procedure, the authors believe that MR imaging is a useful aid for diagnosis in cases of indefinite findings in scrotal and testicular disease.  相似文献   

14.
Dural arteriovenous fistulas: evaluation with MR imaging   总被引:2,自引:0,他引:2  
The preangiographic diagnosis of cerebral dural arteriovenous fistula (DAVF) can be difficult. The magnetic resonance (MR) images of 12 patients with angiographically proved DAVF were evaluated to characterize the appearance of these lesions and to identify those patients at increased risk for complications. Patients with DAVF demonstrating venous occlusive disease are at higher risk for complications from the arterialized collateral venous system. This venous occlusive disease is demonstrated best at arteriography. The MR imaging appearance of dilated cortical veins without a parenchymal nidus is suggestive of a DAVF with veno-occlusive disease. Eight of the 12 patients in our series demonstrated this finding at angiography. Complications, including infarction and hemorrhage, were identified at MR imaging in eight patients with MR imaging evidence of veno-occlusive disease. At angiography 42% of these complications were not apparent. In one patient with a DAVF draining into an unobstructed right sigmoid sinus, results of MR study were normal. Although patients with DAVF without veno-occlusive disease may have normal findings at MR imaging, DAVF associated with veno-occlusive disease and dilated pial venous drainage can be documented on MR images. This subset of DAVF patients, many of whom were identified only at MR imaging, is at higher risk for complications due to veno-occlusive disease. These patients are believed to require more urgent therapy. MR imaging is useful in the pretherapeutic planning for patients with DAVF.  相似文献   

15.
A series of 25 patients with biopsy proven adenocarcinoma of the prostate underwent preoperative staging evaluation with a digital rectal examination, endorectal ultrasound, and body coil magnetic resonance imaging (MRI) before their radical retropubic prostatectomy. The sensitivity and specificity of the digital rectal examination for the detection of extracapsular disease were 17 and 100%, respectively. The sensitivity and specificity of endorectal ultrasound for the detection of extracapsular disease were 35 and 89%, respectively. The sensitivity and specificity of body coil MRI for the detection of extracapsular disease by adenocarcinoma of the prostate were 47 and 63%, respectively. Microscopic disease of the capsule and seminal vesicles was the principle reason for understaging by both imaging modalities. This small series suggests that both imaging modalities are marginally more sensitive, albeit less specific, for extracapsular disease of the prostate than the digital rectal examination, with ultrasound having a slight edge in specificity and MRI having a slight edge in sensitivity.  相似文献   

16.
Caroli's disease: magnetic resonance imaging features   总被引:2,自引:0,他引:2  
Our objective was to describe the main aspects of MR imaging in Caroli's disease. Magnetic resonance cholangiography with a dynamic contrast-enhanced study was performed in nine patients with Caroli's disease. Bile duct abnormalities, lithiasis, dot signs, hepatic enhancement, renal abnormalities, and evidence of portal hypertension were evaluated. Three MR imaging patterns of Caroli's disease were found. In all but two patients, MR imaging findings were sufficient to confirm the diagnosis. Moreover, MR imaging provided information about the severity, location, and extent of liver involvement. This information was useful in planning the best therapeutic strategy. Magnetic resonance cholangiography with a dynamic contrast-enhanced study is a good screening tool for Caroli's disease. Direct cholangiography should be reserved for confirming doubtful cases. Electronic Publication  相似文献   

17.
Childhood adrenoleukodystrophy is an X chromosome-linked disorder characterized by progressive demyelination of cerebral white matter and adrenal insufficiency. Magnetic resonance (MR) imaging was performed in 15 patients with symptomatic disease and three with presymptomatic disease. MR imaging findings were abnormal only in symptomatic patients. Major sites of disease were the occipital, parietal, and temporal lobes, with all patients showing involvement of occipital lobes, optic radiations, and splenium of the corpus callosum. Follow-up images obtained in four patients demonstrated a posterior-to-anterior progression of disease. Correlation of results from MR imaging with those from evoked potential studies indicated that MR imaging was the method of choice for detecting demyelination of visual, auditory, and motor systems in adrenoleukodystrophy.  相似文献   

18.
A series of 25 patients with biopsy proven adenocarcinoma of the prostate underwent preoperative staging evaluation with a digital rectal examination, endorectal ultrasound, and body coil magnetic resonance imaging (MRI) before their radical retropubic prostatectomy. The sensitivity and specificity of the digital rectal examination for the detection of extracapsular disease were 17 and 100%, respectively. The sensitivity and specificity of endorectal ultrasound for the detection of extracapsular disease were 35 and 89%, respectively. The sensitivity and specificity of body coil MRI for the detection of extracapsular disease by adenocarcinoma of the prostate were 47 and 63%, respectively. Microscopic disease of the capsule and seminal vesicles was the principle reason for understaging by both imaging modalities. This small series suggests that both imaging modalities are marginally more sensitive, albeit less specific, for extracapsular disease of the prostate than the digital rectal examination, with ultrasound having a slight edge in specificity and MRI having a slight edge in sensitivity.  相似文献   

19.
目的 探讨血清甲状旁腺激素(PTH)升高的甲状旁腺相关疾病的核医学诊断方法和体会.方法 对25例甲状旁腺相关疾病患者进行99Tcm-MIBI SPECT双时相法甲状旁腺显像及99Tcm-亚甲基二膦酸盐(99Tcm-MDP)全身骨静态显像法显像,同时测定血清PTH和血清钙、磷及碱性磷酸酶含量.结果 ①原发性甲状旁腺功能亢进(PHPT)和继发性甲状旁腺功能亢进(SHPT)者血清PTH水平呈不同程度升高,其中PHPT较明显.②PHPT和SHPT患者手术前后PTH水平的变化明显,t分别为6.24和6.85,P均<0.01;③PHPT患者全身骨显像常呈典型的代谢性骨病骨显像特点,甲状旁腺99Tcm-MIBI双时相显影阳性率为90%以上;④SHPT患者全身骨显像表现多样,常因血本底偏高,骨/组织放射性计数值降低,使骨显像的清晰度受到影响,但通常以骨摄取显像剂增多为主.99Tcm-MIBI双时相甲状旁腺显像多有不同程度的甲状旁腺增生,达56%以上.结论 甲状旁腺、全身骨SPECT检查结合血清PTH水平测定的方法对甲状旁腺相关疾病的诊断及指导治疗具有很高的临床应用价值.  相似文献   

20.
A prospective study was undertaken to compare the accuracy of surface coil magnetic resonance (SCMR) imaging, metrizamide myelography (MM), and computed tomography with metrizamide (CTM) in the determination of cervical radiculopathy. Surgical findings were the objective measure of accuracy. Fifty-two patients underwent all imaging studies. Studies were evaluated for disease location and type (bone vs. soft tissue). Twenty-eight patients underwent subsequent cervical surgery at 39 levels form an anterior interbody approach. Predictions made with SCMR imaging were surgically confirmed in 74% of patients, with CTM in 85%, and with MM in 67%. There was 90% agreement with surgical findings when SCMR imaging and CTM were used jointly, and 92% agreement when CTM and MM were used jointly, In general, SCMR imaging was as sensitive as CTM for identification of disease level, but not as specific for type of disease. MM was the modality least specific for disease type. The major advantage of CTM was its ability to distinguish bone from soft tissue, for which contrast material is unnecessary. SCMR imaging is a viable alternative to MM and, together with computed tomography, if needed, provides a thorough examination of the cervical region.  相似文献   

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