MAGNETIC RESONANCE IMAGING IN POSTERIOR CIRCULATION INFARCTION: IMPACT ON DIAGNOSIS AND MANAGEMENT

To compare the diagnostic yield of magnetic resonance imaging (MRI) with computed tomography (CT) in posterior circulation infarction, we used proton MRI with a 0.3 Tesla magnet and a 3rd generation CT scanner in 25 patients. Age-matched controls were compared in a blinded fashion. Seventeen patients (68%) showed relevant pathology on MRI not seen on CT, 11 with normal CT and six with more extensive lesions, chiefly in the brain stem. Evidence of abnormal vertebrobasilar blood flow was seen in 8/25 (32%) of patients, suggested by vascular high intensity signals on MRI. Two tissue and one flow abnormality were seen in the control group. MRI provides additional information concerning infarct site, extent and pathogenesis in posterior circulation infarction.     

Delineating the sites and progression of in vivo atrophy in multiple system atrophy using fluid-registered MRI.

We describe the pattern and progression of atrophy delineated using fluid registration of serial magnetic resonance imaging scans in a case of multiple system atrophy (MSA). The in vivo findings were consistent with those found at postmortem, including significant supratentorial atrophy concurrent with an unusual degree of cognitive impairment for MSA.     

''Gender gap'' in multiple sclerosis: magnetic resonance imaging evidence

The authors evaluated the gender difference in the magnetic resonance imaging characteristics of the lesions occurring in the brain of 413 multiple sclerosis (MS) patients. Men had fewer contrast-enhancing lesions (P = 0.01), but a higher proportion of lesions evolving into 'black holes' (P = 0.001), when compared with women. Thus, our data indicate that men with MS are prone to develop less inflammatory, but more destructive lesions than women. This study results provides support for a modulation of the MS pathological changes by gender.     

Surgical relevance of diagnostic imaging techniques in pretherapeutic staging of carcinoma of the esophagus, stomach, colon and rectum

Summary. The increasing spectrum of therapeutic options for tumors of the gastrointestinal tract has resulted in a refinement of the pretherapeutic diagnostic strategies. The diagnostic approach in surgical institutions that are focused on primary surgical resection will therefore be much less sophisticated than in institutions who propose a selective therapeutic approach based on the pretherapeutic tumor stage and prognostic parameters. Pretherapeutic assessment of the depth of tumor infiltration, i. e. the T-category, is essential because most further diagnostic and therapeutic decisions are based on this information. This can today be achieved with a high degree of accuracy by endoscopy and endoscopic ultrasonography. Early T-stages (T1–2) are usually an indication for primary surgical resection and, after exclusion of distant metastases, no further diagnostic studies are required. In patients with locally advanced esophageal, gastric or rectum tumors (T3–4) multimodal therapeutic concepts should be considered. This usually requires additional diagnostic studies. None of the available diagnostic imaging modalities today allows satisfactory pretherapeutic assessment of lymph node metastases. The assumed nodular status should therefore currently not influence therapeutic decisions. Essential is, however, the assessment of distant metastases, since the documentation of distant tumor spread will change the therapeutic approach to a palliative situation. Detailed histologic and molecular-biologic assessment of tumor characteristics is growing in importance. This not only provides therapeutically relevant information regarding tumor grading, but opens the door towards a modern molecular diagnostic approach. It can be expected that in the near future a vast amount of relevant prognostic information can be obtained from endoscopic tumor biopsies, which may soon alter our therapeutic concepts.      

Perfusion imaging by a flow-sensitive alternating inversion recovery (Fair) technique: Application to functional brain imaging

Perfusion is a crucial physiological parameter for tissue function. To obtain perfusion-weighted images and consequently to measure cerebral blood flow (CBF), a newly developed flow-sensitive alternating inversion recovery (FAIR) technique was used. Dependency of FAIR signal on inversion times (TI) was examined; signal is predominantly located in large vessels at short TI, whereas it is diffused into gray matter areas at longer TI. CBF of gray matter areas in the human brain is 71 ± 15 SD ml/100 g/min (n = 6). In fMRI studies, micro- and macrovessel inflow contributions can be obtained by adjusting TIs. Signal changes in large vessel areas including the scalp were seen during finger opposition at a TI of 0.4 s; however, these were not observed at a longer TI of 1.4 s. To compare with commonly used BOLD and slice selective inversion recovery techniques, FAIR and BOLD images were acquired at the same time during unilateral finger opposition. Generally, activation sites determined by three techniques are consistent. However, activation of some areas can be detected only by FAIR, not by BOLD, suggesting that the oxygen consumption increase couples with the CBF change completely. Relative and absolute CBF changes in the contralateral motor cortex are 53 ± 17% SD (n = 9) and 27 ± 11 SD ml/100 g/min (n = 9), respectively.     

MR imaging of the brain in patients with hepatic form of Wilson''s disease

The aim of this study was to detect the sites and frequency of possible lesions by brain magnetic resonance imaging (MRI; 1,5T) in a group of 16 neurologically asymptomatic patients with hepatic form of Wilson's disease (WD; seven untreated and nine under treatment). Abnormal MR findings of the brain were found in 75% of patients. Lesions in brain parenchyma were detected in all untreated, drug-naive patients and in 44% of treated patients. Abnormal signal in globus pallidus, putamen, and caudate nucleus was revealed in 86, 71 and 71% of treated and in 33, 33 and 22% of untreated patients, respectively. In five of eight patients with putaminal pathology (62.5%) and in four of seven patients with caudate nuclei involvement (57%), only proton density 2-weighted sequence (PDW) exhibited sensitivity for lesion detection, with both T1W and long echo T2W sequences being insensitive. This superiority of PDW sequence was even more pronounced in the group of untreated patients in whom 80% of putaminal pathology was visible exclusively on this sequence. The lower frequency of lesions in the group of treated in comparison with untreated patients indicated that they might be reversible in the course of chronic chelating therapy.     

A method of simultaneous dual-radionuclide cardiac imaging with technetium 99m and thallium 201. I: Analysis of interradionuclide crossover and validation in phantoms

Background  

Simultaneous dual-radionuclide technetium 99m/thallium 201 scintigraphy can potentially produce perfectly aligned stress and rest images in less time than conventional protocols. However, interradionuclide crossover limits diagnostic accuracy. Accordingly, we evaluated^99mTc and²⁰¹Tl crossover in line and heart phantoms.     

Renal metastasis from choriocarcinoma: MRI appearance

Choriocarcinoma is the most malignant tumor of gestational trophoblastic neoplasia. It grows rapidly and metastasizes to the lung, liver, and, less frequently, to the brain. Renal involvement is rare. Magnetic resonance imaging (MRI) is a useful modality to image the affected tissues; it contributes to the evaluation and management of the disease. One case of renal choriocarcinoma with MRI evaluation is reported. Received: 24 February 1997/Accepted: 14 April 1997     

MR appearances of urinary bladder in amyloidosis associated with multiple myeloma

Amyloidosis led to thickening of the urinary bladder wall, with hypointensity in T2-weighted images, which was distinguished from multiple myeloma involvement. Received: 3 April 1995/Accepted: 7 August 1995     

胰腺实性-假乳头状瘤影像与病理诊断分析

目的 探讨胰腺实性-假乳头状瘤的影像及病理学的诊断要点。资料与方法 回顾分析11例经手术切除、病理学和免疫组织化学证实的胰腺实性一假乳头状瘤患者的临床资料，以比较其影像和病理学特点。结果 (1)本病多发于30岁以下女性，临床主要表现为腹痛。(2)CT、MRI表现为肿瘤内有实性和囊性结构，可分为3型；特征性表现为“浮云征”。(3)肿瘤大部分位于胰腺，多有完整包膜，不伴有胆总管扩张。(4)病理学特点为肿瘤实性部分由实性区、假乳头区及两者过渡区以不同比例混合而成。囊性区由坏死、液化、陈旧性出血组成。(5)肿瘤的囊实性结构是形成“浮云征”的病理基础。结论 胰腺实性-假乳头状瘤有相对特征性的影像和病理学表现，术后预后较好。