Scatter correction in scintigraphy: the state of the art

In scintigraphy, the detection of scattered photons degrades both visual image analysis and quantitative accuracy. Many methods have been proposed and are still under investigation to cope with scattered photons. The main features of the problem of scattering in radionuclide imaging are presented first, to provide a sound foundation for a critical review of the existing scatter correction techniques. These are described using a classification relating to their aims and principles. Their theoretical potentials are analysed, as well as the difficulties of their practical implementation. Finally, the problems of their evaluation and comparison are discussed. Correspondence to: I. Buvat     

Erfahrungen zur PFFB von isolierten radiusköpfchenfrakturen

Zusammenfassung Den Vorteilen einer osteosynthetischen Versorgung einer Fraktur mit sofortiger Aufnahme seiner Funktion, stehen die aus der Literatur bekannten Komplikationen gegenüber. Diese und unsere eigenen unbefriedigenden Ergebnisse nach der operativen Versorgung von Radiusköpfchenfrakturen ließen uns zu einer prospektiven randomisierten Studie einer primär funktionellen Behandlung unter Verzicht auf eine äußere oder innere Stabilisierung greifen. Seit Dezember 1991 haben wir im UKH-Graz bis einschließlich Dezember 1992 insgesamt 70 Patienten nach einem strikten Behandlungskonzept, unter Zuhilfenahme der Computertomographie zur Verlaufsbeobachtung versorgt. Die in 91% der Fälle als sehr gut and gut einzustufenden Frühergebnisse sowie das fehlende Auftreten einer, wie bei operativer Versorgung möglichen Komplikation, ebenso die zusätzlich deutlich frühere Arbeitsfähigkeit bzw. deutlich kürzere, wenn auch aufwendigere Behandlungszeit, lassen uns diese Verfahren nicht nur in unserem Hans weiterführen, sondern können wir auch weiter empfehlen.

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Experience with internal fixation of fractures of the head of the radius

The advantages of internal fixation of fractures, with the possibility of immediate resumption of the function of the fractured bone, are in contrast to the well-known complications described in the literature. These complications and our own unsatisfactory results after surgical treatment of fractures of the head of the radius induced us to carry out a randomized prospective study of primary functional treatment of such fractures without external or internal stabilization. From December 1991 through December 1992, a total of 70 patients were treated according to a strict treatment protocol at the Graz Hospital for Accident Surgery, and CT was used for observation of the healing process. The positive early results, which in 91% of all cases were classified as very good or good, the lack of complications that sometimes follow surgical treatment, the markedly earlier recovery of the patient's working capacity, and the clearly shorter — albeit somewhat more expensive — treatment period required have led us to continue using this method at our hospital and also to recommend its use elsewhere.

     

Exogastric neurilemmoma presenting as acute abdomen: Role of computed tomography in diagnosis

A case of subserosal gastric neurilemmoma is hereby presented. This reported case is unique in its clinical presentation including the appearance of acute abdomen and fever subsequent to unremarkable and uneventful upper gastrointestinal endoscopy. The tendency of neurilemmoma to cause mucosal ulceration with fistula formation probably led to this clinical presentation. The role of computed tomography in establishing diagnosis of exogastric tumor is emphasized.     

MRI and SPECT findings in amyotrophic lateral sclerosis

Summary MRI was performed in 21 patients and single photon emission computed tomography (SPECT) withN-isopropyl-p-¹²³I iodoamphetamine in 16 patients, to visualize upper motor neurone lesions in amyotrophic lateral sclerosis. T2-weighted MRI revealed high signal along the course of the pyramidal tract in the internal capsule and cerebral peduncle in 4 of 21 patients. SPECT images were normal in 4 patients, but uptake was reduced in the cerebral cortex that includes the motor area in 11.     

Human brain atlas: For high-resolution functional and anatomical mapping

We present the new computerized Human Brain Atlas (HBA) for anatomical and functional mapping studies of the human brain. The HBA is based on many high-resolution magnetic resonance images of normal subjects and provides continuous updating of the mean shape and position of anatomical structures of the human brain. The structures are transformable by linear and nonlinear global and local transformations applied anywhere in 3-D pictures to fit the anatomical structures of individual brains, which, by reformatting, are transformed into a high-resolution standard anatomical format. The power of the HBA to reduce anatomical variations was evaluated on a randomized selection of anatomical landmarks in brains of 27 young normal male volunteers who were different from those on whom the standard brain was selected. The HBA, even when based only on standard brain surface and central structures, reduced interindividual anatomical variance to the level of the variance in structure position between the right and left hemisphere in individual brains. © 1994 Wiley-Liss, Inc.     

Added value of OCT in evaluating the presence of leakage in patients with age-related macular degeneration treated with PDT

Background Evaluating the presence of leakage on fluorescein angiography (FA) in patients with age-related macular degeneration (AMD) retreated with photodynamic therapy (PDT) can be difficult. New diagnostic tools such as optical coherence tomography (OCT) might help to optimize PDT management.Methods Thirty AMD patients scheduled for regular follow-up FA in conjunction with PDT treatment were also scanned with OCT. Follow-up data at 9 months were retrieved from the patients’ medical records. Inter-observer agreement [kappa (κ) coefficient] for the presence of leakage on FA, for OCT parameters for leakage, and agreement between FA and OCT evaluations were calculated. The indication for retreatment was evaluated using the leakage analysis based on FA alone, OCT alone, and both examinations combined, and compared to the actual follow-up of the patients at 9 months.Results Agreement between the two observers for the presence of leakage on FA was moderate (κ=0.51). OCT agreement between the two observers for the presence of leakage was good (κ=0.85). Agreement between FA and OCT for the presence of leakage was poor (κ=0.16). Follow-up data at 9 months on all patients were analyzed. Seven out of 30 patients were not retreated at the time of examination, and four of these patients (57%) remained stable without further treatment. Twenty-three patients did receive a PDT treatment at the time of examination; and eight of these patients did not show leakage on OCT, and five of these patients (62%) remained stable without additional treatment. In contrast, only three out of 15 patients (20%) with leakage on both FA and OCT remained stable during this 9 month follow-up period.Conclusions Inter-observer agreement for the presence of leakage was moderate for FA and good for OCT. There was considerable disagreement between leakage as judged by OCT and by FA. OCT could be of help in the decision regarding PDT retreatment. Assuming that 57% of the patients without leakage either on FA or OCT would remain stable without retreatment, the rate of probable ineffective retreatment could be reduced from 35% to 20%.There was no financial support for this study. The authors have full access to the data and will allow Graefe’s Archive for Clinical and Experimental Ophthalmology to review the data if requeste.d     

造影剂到达腹主动脉的峰值大小与患者因素的关系

目的探讨造影剂到达腹主动脉的峰值大小与患者因素之间的关系。方法108例患者以2.5ml/s注射欧乃派克(300mgI/ml)20ml,12s后采用testbolus技术在腹腔干水平同层动态扫描腹主动脉,用dynamic evaluation软件测得腹主动脉的峰值大小,采用单因素回归分析和多因素逐步回归分析法研究患者的性别、年龄、身高、体重、心率、血压、注射位点、达峰时间及是否有心脏病、糖尿病、或化疗史对造影剂到达腹主动脉峰值大小是否有影响及影响程度。结果造影剂到达腹主动脉峰值大小,在男性平均比女性低;其随年龄、身高、体重、达峰时间的增加而逐渐降低,注射位点在手背静脉其值平均比在肘部静脉低;其不受心率、血压、是否有心脏病、糖尿病或化疗史的影响。参考公式:峰值大小(HU)=383.8400-身高(cm)×1.0909-体重(kg)×0.6760 注射位点×16.7878-达峰时间(s)×1.6882。结论可根据患者的性别、年龄、身高、体重、注射位点和达峰时间来适当调整患者CT血管成像时造影剂用量。     

颅脑外伤性病变的CT检查及其临床意义

目的：探讨颅脑外伤严重程度及CT征象与预后的关系，并探讨CT复查的最佳时间及临床意义。方法：回顾性分析80例颅脑外伤的严重程度与初次CT征象的关系，统计分析复查CT发现新病变的数目、程度及时间。结果：颅脑外伤的严重程度与初次CT征象符合率为92．5％(74／80)。外伤后即刻昏迷、CT显示重度复合伤、脑干损伤或弥漫性脑白质损伤的病死率达70．0％(21／30)。1～3d复查CT发现迟发性病变80个，4—7d21个，7d后8个。结论：临床病情与CT征象变化对判断预后有重要意义，颅脑外伤后3、7d是复查CT的最佳时机，出现病情变化应随时复查。     

~(99m)Tc-MIBI心肌灌注断层显像监测蒽环类药物的心脏毒性

目的 :探讨99mTc-MIBI心肌灌注断层显像在蒽环类药物心脏毒性监测中的价值。方法 :2 3例接受蒽环类药物治疗的患者 ,在治疗前进行心电图、心肌酶学检查、核素心室造影测左室射血分数 (LVEF)和99mTc MIBI心肌灌注断层显像并计算相对定量值。并于每一周期治疗后重复上述检查。结果 :蒽环类药物治疗一周期后 ,2 3例患者心肌相对定量值明显下降 (P <0 .0 1)。其中 11例吡喃阿霉素、6例表阿霉素和 6例米托蒽醌治疗的患者 ,心肌相对定量值明显下降 (P <0 .0 5 ) ,心电图和心肌酶学无明显变化 (P >0 .0 5 )。蒽环类药物治疗多周期后的 10例患者心肌相对定量值较治疗前下降 (P <0 .0 5 )。 9例患者的心肌相对定量值 (最大累积剂量为 2 0 0mg/m2 )与一周期后无明显差别 (P >0 .0 5 )。10例患者治疗前及多周期治疗后LVEF均 >6 0 %,且化疗前后无明显差别 (P >0 .0 5 )。结论 :99mTC MIBI心肌灌注断层显像能监测蒽环类药物所致的心肌损害 ,且较左室射血分数敏感 ,比心电图和心肌酶学检查优越 ,有利于指导蒽环类药物的临床应用。     

老年认知功能障碍与脑结构CT测量的相关性研究

目的探讨脑萎缩与老年认知功能障碍之间的相关性。方法对开滦集团公司1063名离退休职工进行健康查体,用简易精神状态量表(MMSE)评定认知功能,按分界值将本次研究对象分为认知功能障碍组和认知功能正常组,同时用CT线性测量脑的相关部位以诊断脑萎缩情况,并对各型脑萎缩与认知功能的相关系数及提示老年认知功能障碍的敏感度、特异度、准确度进行分析。结果1063名观察对象中符合入选标准并资料完整者共计511名,其中108名有认知功能障碍,髓质脑萎缩55名、皮质萎缩5名、混合型萎缩30名;认知功能正常者403名,髓质脑萎缩214名、皮质萎缩13名、混合型萎缩62名。认知功能障碍组脑萎缩的发病率高于认知功能正常组,差异具有统计学意义(P<0.005);2组间颞叶海马钩回间距(26.86mm±3.73mmvs25.95mm±3.80mm)及海马钩回间距/大脑左右径的比值(0.21±0.02vs0.20±0.02)差异具有统计学意义(P<0.05);海马钩回间距、皮质脑萎缩、混合型脑萎缩与认知功能障碍呈负相关(分别为r=-0.094,P=0.034,r=-0.156,P≈0.000,r=-0.147,P≈0.000),以海马钩回间距20mm提示老年认知功能障碍的敏感度最高(98.14%),混合型脑萎缩的特异度(84.86%)、准确度最高(72.80%)。结论CT测量相关脑结构,判断脑萎缩类型可以为老年认知功能障碍的诊断提供有价值的信息。