Changes in the basal ganglia and thalamus following reperfusion after complete cerebral ischaemia

We report specific changes bilaterally in the basal ganglia and thalamus following reperfusion after complete cerebral ischaemia. A 69-year-old man, resuscitated after cardiac arrest, showed symmetrical lowdensity lesions in the head of the caudate nucleus and lentiform nucleus on CT. MRI revealed methaemoglobin derived from minor haemorrhage in the basal ganglia and thalamus, not evident on CT. We suggest that this haemorrhage results from diapedesis of red blood cells through the damaged capillary endothelium following reperfusion.     

延颈髓交界处髓内肿瘤的诊断与显微手术治疗

报道显微手术治疗10例延颈髓交界处髓内肿瘤(ITCJ),肿瘤全切除6例,次全切除4例,无手术死亡,70％病例术后好转。ITCJ可分为颈延型和延颈型两大类型。MRI是诊断本病的主要方法,并且具有指导手术的重要意义。结果也表明,显微手术方法和术后呼吸功能监护很有必要。     

Infantile hypopituitarism: etiological variability evidenced by MRI

In this study, magnetic resonance imaging (MRI) was performed to document potentially present morphostructural abnormalities of the hypothalamopituitary region in seven infants (age 0–21 months) who presented very early in life with clinical and biochemical evidence of hypopituitarism. Four infants had associated congenital cerebro-facial malformations.The following anatomical abnormalities were identified in variable combinations: ectopic neurohypophysis absence of the pituitary stalk, extreme elongation of the pituitary stalk, aplasia of the anterior pituitary lobe and no identification of the hypothalamopituitary complex.MRI proved to be very sensitive in the identification of structural malformations of the hypothalamopituitary region in infants with or without cerebro-facial malformations. AllhwuLll the magnetic resonance image does not appear to be a good predictor of endocrine dysfunction, it provides us more insight into the precise aetiology of this disorder and may be therefore of diagnostic, prognostic and therapeutic importance.     

Orbital Hydatid Cyst: CT and MRI

Orbital hydatid cyst is rare. We present a case with CT and MRI, emphasizing the superiority of the latter. Received: 19 August 1996 Accepted: 9 September 1996     

Diffusion-weighted magnetic resonance imaging for demonstration of cerebral infarcts

Summary Forty-one patients demonstrating clinical symptoms for cerebral infarction were investigated by magnetic resonance imaging with diffusion-weighted echo-planar imaging (DWI) and T2-weighted imaging (T2WI). In 8 patients only DWI showed the cerebral lesions clearly. One patient with positive DWI and T2WI suffered from HSV encephalitis. DWI is superior to T2WI in assessment of small cortical infarcts and cerebral infarction in patients with preexisting vascular lesions. DWI is not specific, so other causes like cerebral hematoma and encephalitis have to be considered.      

MRI of a family with focal abnormalities of gyration

Focal abnormalities of gyration (FAG) are developmental disorders that may occur in isolated patients or, as in the case being reported, as part of a familial disorder. Analysis of individuals in a family spanning three generations was carried out using MRI. Abnormalities, present in all members of generations II and III, included focal cortical dysplasia (three patients), focal cortical infolding (two patients) and schizencephaly (one patient); associated minor anomalies, such as white matter abnormalities, were seen in the remaining three members of generations II and III. MRI recognition of FAG in the family being reported proved useful in defining their phenotypical expression and providing proper counselling for individual family members. Received: 22 August 1996 Accepted: 7 October 1996     

Characterization and prediction of gradient acoustic noise in MR imagers

Gradient acoustic noise has been measured and characterized for an epoxy-potted, shielded gradient assembly in a 1.5 T MRI system. Noise levels vary by 10 dB or more as a function of longitudinal position in the scanner and reflect the pattern of forces applied to the gradient assembly. The noise level increases slightly (1–3 dB) with a patient in the scanner. The spectrum of the noise is similar (but not identical) to the spectrum of the input signal. A gradient-pulse-to-acoustic-noise transfer function was obtained by using a white noise voltage input to the gradient system. The transfer function enabled us to accurately predict acoustic noise output for a pulse sequence consisting of a series of trapezoidal pulses on a single axis and for a clinical fast spin echo sequence with gradients present on all three axes.     

Flow-independent angiography for peripheral vascular disease: Initial in-vivo results

Flow-independent angiography (FIA), an approach that isolates arterial blood using MR relaxation characteristics rather than flow effects, was evaluated for application in peripheral vascular disease (PVD). First, pilot studies were conducted in which FIA coronal projection images were obtained from controls and symptomatic patients with PVD to assess clinical utility. All control images corresponded to the expected leg arterial anatomy with little interference from deep veins (one of five) and muscle (zero of five). Superficial venous signal was less well suppressed in comparison to deep veins (four of five). Images of symptomatic patients were less consistent with difficulty suppressing muscle and deep venous signal in some cases and edema when present. We then compared T2 values for muscle (T2_m, tibialis anterior), arterial blood (femoral and popliteal arteries), and venous blood (femoral, popliteal, and saphenous veins) in controls (n = 8) and symptomatic patients with intermittent claudication (n = 5) or ischemic rest pain (n = 7). Changes in T2 measurements of various tissues accounted for poorer contrast in symptomatic patients. Patients with ischemic rest pain had significantly higher T2_m compared with controls (T2_m = 39.3 ± 2.1 (1 standard error of the mean [SEM]) versus 30.9 ± .4, P < .01). For all measurements, other than saphenous vein, variances were greater in symptomatic patients. To realize the inherent advantages of FIA for this clinical application, additional work on suppression of signals from muscle, veins, and edema is required. One promising approach involves shifting from projection images to three-dimensional acquisitions for improved tissue suppression.     

Retardation of pain development: a case of recovery from congenital insensitivity to pain

Congenital analgesia is a rare genetic disorder. We report here that a 12-year-old boy was able to recover from congenital insensitivity to pain. Neurological examinations revealed that there was a 'stocking' distribution of pain decrement on the lower extremities under the patient's knee joints. Magnetic Resonance Imaging (MRI) of his brain showed gyrus thinning with sulcus widening at both sides of the parietal lobe. Southern blot hybridization probed with cDNAs of various opioid receptors did not detect any significant abnormality. Our results suggest that this rare case may not be genetically determined.