Non-invasive temperature imaging of muscles with magnetic resonance imaging using spin-echo sequences

The application of spin-echo magnetic resonance imaging sequences on non-invasive temperature imaging for temperature mapping of human limbs is investigated. In an in vitro expriment performed on a meat sample, the equilibrium magnetisation P and the spin-lattice relaxation time T₁ are calculated from the values for the repetition time TR and the signal intensities obtained by a spin-echo sequence at different tissue temperatures tures as measured by a fibre-optic probe. T₁ is linearly correlated to the tissue temperature, and P is linearly correlated to the reciprocal value of the absolute temperature. Both effects, taken together, lead to a non-linear dependency of the signal intensity on temperature. Therefore a TR leading to maximum temperature dependency of the signal intensity is calculated and used in the futher experiments. In the in vivo experiments, the lower legs of two volunteers are cooled from outside. Images are acquired with a spin-echo sequence (1.5T, TR=1200 ms, TE=10 ms). A rise in signal intensity in the muscle with falling skin temperature is observed, particularly in more peripheral muscle layers. This study shows that spin-echo sequences can be used to monitor temperature changes and temperature differences in living muscle tissue.     

Blood pool ventriculography with a new technetium-labelled complex (99mTc-DEPIC) : a clinical evaluation

A new, single bolus method of in vivo blood pool imaging using a technetium Tc99m phosphine isocyanide complex (DEPIC) which binds to pre-albumin was evaluated in volunteers (n=4) and patients (n=20). DEPIC was assessed for its safety and possible drug interactions. Its duration of action and quality of ventriculography were compared with imaging using standard in vivo red cell labelling (PYP) during two 3-h scanning periods 1 week apart. DEPIC had a mean plasma halflife of 3.3 h. The count rate over the left ventricle was initially 42% higher with DEPIC than with PYP. However, removal of DEPIC by the liver resulted in equivalent count rates by 1 h, and by 3 h PYP count rates were 22% higher than DEPIC. Immediately post injection mean (SD) difference in the left ventricular ejection fraction between the two methods was 2.4% (7.7%). Satisfactory DEPIC scans were obtained up to 2 h post injection, but by 3 h there was a mean difference of 13% (11.3%). DEPIC was found to be a safe alternative to red all labelling for blood pool angiography, suitable for routine work. The single bolus methodology and high initial count rates offer improved efficiency and a capability for truly emergency scanning.     

Gliomatosis cerebri with good prognosis

A 52-year-old man was admitted to our clinic with severe headache and bilateral papilledema. Magnetic resonance (MR) images on admission demonstrated diffuse swelling of the cerebral cortex without formation of a tumor mass. Biopsy revealed diffuse infiltration with neoplastic glial cells. After radiation and chemotherapy, the MR images returned to normal. The morphological and neurological features of the present case met the criteria for gliomatosis cerebri. However, this patient showed an unusually good response to radiation and chemotherapy.     

核素显像对小儿消化道出血的病因诊断

目的探讨核素显像对小儿消化道出血，特别是对Ｍｅｃｋｅｌ憩室、肠重复畸形的病因诊断的价值。方法对２６例腹痛、便血为主要症状的患儿行９９ｍ锝酸盐（９９ｍＴｃＯ－４）显像，其中１２例显像阴性者于检查后２４小时有活动性出血者，再行９９ｍ锝标记红细胞显像。所有病例的诊断均经手术、病理及内窥镜等检查所证实。结果９９ｍＴｃＯ－４显像诊断Ｍｅｃｋｅｌ憩室和肠重复畸形的敏感性、特异性、准确性分别为８５．７％（１２／１４）、９１．７％（１１／１２）及８８．５％（２３／２６）。结论核素显像具有无创、方法简单易行等特点，特别是对异位胃粘膜诊断具有较好的灵敏性和特异性。核素显像可作为下消化道出血病因诊断的有效方法。     

窥视下尿道内切开术治疗尿道狭窄或闭锁

采用窥视下尿道内切开术治疗尿道狭窄或闭锁５３例，其中４８例治疗成功。狭窄闭锁段≤３ｃｍ者，单纯冷刀切开即可；＞３ｃｍ者，冷刀切开后需加电刀切除疤痕组织，扩大尿道，尿道内皮管植入。３６例患者术后随访１～８年（平均４年６个月），２７例排尿通畅，尿流率和性功能正常。本文就操作要点和并发症防治等进行了详细讨论。     

Image technique optimization in MR imaging of a titanium alloy joint prosthesis

The purpose of this study was to explore systematically the effect of the imaging parameters changeable by the user in spin-echo (SE) imaging sequences to minimize image distortion when imaging joint prostheses. A titanium alloy hip joint prosthesis was studied at 1.0 T. The SE imaging parameters were bandwidth/pixel (BW/p), TE, strength of encoding gradients (matrix size), echo train length (ETL), and direction of phase and frequency encoding. The effect of ETL in rapid acquisition relaxation enhanced (RARE) sequences was also evaluated with a turbo-SE sequence using a different ETL with the same TR and an effective TE. It is concluded that an optimized image quality can be achieved in SE imaging by using a high bandwidth/pixel value (at least 130 Hz/pixel), a high resolution matrix (256–512), sequences with multiple refocusing, and a frequency-encoding axis parallel to the long axis of the prosthesis. The degree of distortion is reduced with this optimized technique.     

~(99m)Tc-甲氧基异丁基异腈首次通过法心室显像评价左心室收缩功能

应用９９ｍＴｃ－甲氧基异丁基异腈（ＭＩＢＩ）对２９例受检者进行首次通过法心室显像，测定左室射血分数（ＬＶＥＦ），并与同期平衡法心室显像测得的ＬＶＥＦ进行相关分析。结果：首次通过法和平衡法心室显像测得的ＬＶＥＦ分别为（４６．５±１６．７）％、（４９．１±１６．１）％（Ｐ＞０．０５）。相关分析结果显示，二者有明显的相关（ｒ＝０．７８７，Ｐ＜０．０１）。结果表明：９９ｍＴｃ－ＭＩＢＩ为心肌显像剂，采用首次通过法心室显像，在观察心肌血流改变的同时，可准确可靠地评价左室收缩功能状态。     

MELAS presenting as migraine complicated by stroke: case report

A case of MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) which presented as migraine complicated by stroke is reported. Strokes associated with migraine have often been reported, but the mechanism remains unclear and may include a variety of pathologies. MELAS also presents with migrainous headache, vomiting, and stroke-like symptoms. Magnetic resonance imaging demonstrates characteristic findings. MELAS should be considered in the differential diagnosis of infarct-like lesions with migrainous headaches in young adults, especially if the symptoms fluctuate and are accompanied by a homonymous hemianopia. Received: 23 September 1996 Accepted: 19 February 1997     

Isolated oculomotor nerve paralysis in Lyme disease: MRI

Lyme disease is a cause of illness involving multiple organ systems, including, in 10–15 % of cases, the nervous system. Peripheral radiculoneuritis, cranial neuritis, encephalitis and myelitis are among the neurological manifestations found in the second and third stages. We present the MRI findings in isolated oculomotor nerve involvement by Lyme disease and discuss the differential diagnosis. Received: 14 June 1995 Accepted: 16 January 1996