Hematopoietic recovery after 10-Gy acute total body radiation

Considerable data suggest that very high doses of acute total body radiation destroy most hematopoietic stem cells and that recovery is possible only after a bone marrow transplant. We review data from a radiation accident victim exposed to about 10-Gy or more acute total body radiation. Total dose and uniformity of distribution were confirmed by physical measurements (paramagnetic resonance), computer simulation, and biologic dosimetry (granulocyte kinetics and cytogenetic abnormalities). Treatment consisted of supportive measures, transfusions, and hematopoietic growth factors (granulocyte-macrophage colony-stimulating factor and interleukin-3). Hematopoietic recovery occurred slowly. Granulocytes were detectable throughout the postexposure period, exceeding 0.5 x 10(9)/L by day 37. There was slower and incomplete recovery of red blood cells and platelets. Increases in blood cell production were paralleled by morphologic changes in bone marrow biopsies. Gastrointestinal toxicity was moderate. Death from a probable radiation pneumonitis infection occurred on day 130. These data indicate the possibility of hematopoietic recovery after approximately 10 Gy or more acute total body radiation without a transplant. They also suggest that lung rather than gastrointestinal toxicity may be dose-limiting under these circumstances.     

Neonatal hyperchloremia related to bromide poisoning]

Hyperchloremia may reveal bromism during the neonatal period. The authors report on two cases of neonatal bromism. The first case concerns triplets without clinical signs although the children and their mother displayed hyperchloremia. In the other case a 6 week old infant displayed neurological abnormalities associated with hyperchloremia and elevated plasma bromide levels.     

Neonatal consequences of premature rupture of membranes (more than five days) before the 34th week of gestation]

Twenty-six cases of premature braking of the membranes which occurred before week 34 of amenorrhea and lasted for more than 5 days are assessed retrospectively. The mean age when the membranes broke was 26.6 weeks of amenorrhea. Delivery occurred on average at 31.5 +/- 2 WA, with an interval of between 6 and 91 days (mean 35 +/- 23 days). In 4 cases, chorioamniotitis complicated the premature breaking of the membranes. The perinatal mortality rate was 5 out of 27, including 2 still births. Nine of the neonates showed respiratory distress which required artificial ventilation. Four cases of pulmonary hypoplasia were confirmed by pathological examination. In all cases, this was associated with a reduction in the volume of the amniotic fluid, reduced fetal mobility and delayed intrauterine growth. In contrast, when these three factors were absent the prognosis was always good, regardless of the date at which the membranes broke. In the long term, the surviving children showed no neurological sequelae.     

Fungal sinusitis: diagnosis with CT and MR imaging

Of 293 patients who underwent computed tomography (CT), surgery, and pathologic examination for chronic sinusitis, 25 had a diagnosis of fungal sinusitis at pathologic examination. Of these, 22 had foci of increased attenuation at CT (in four patients the mean representative CT number [Hounsfied unit] was 122.2 HU [SD, 8.2 HU]), and three did not. Of the 22, 19 patients (76%) met the CT criterion of this study (there was a 12% false-positive and a 12% false-negative diagnostic rate). Six of the 19 patients and one additional patient underwent magnetic resonance (MR) imaging, and all demonstrated remarkably hypointense signal characteristics on T2-weighted images. The findings at MR imaging therefore appear more characteristic of fungal sinusitis than the findings at CT. Furnace atomic absorption spectrometry showed increased concentrations of iron and manganese in mycetoma compared with their concentrations in bacterially infected mucus. This finding and the presence of calcium in the fungal concretion may explain the hypointense T2-weighted signal on MR images.     

Detection of pneumocystis DNA in nasopharyngeal aspirates of leukaemic infants with pneumonia

The technique of polymerase chain reaction was used to detect Pneumocystis carinii DNA in nasopharyngeal secretions of three infants with leukaemia who had the clinical features of P carinii pneumonia. The use of this non-invasive technique allowed the early diagnosis and treatment of these infants whose protocols did not include the use of prophylactic co-trimoxazole.     

Real-time interactive color flow MR imaging

Real-time interactive color flow magnetic resonance (MR) imaging is a combination of real-time MR imaging and color encoding of velocity-induced phase angle. Flow-compensated (FC) and flow-encoded (FE) images are acquired continuously by using gradient echoes and a 12-msec repetition time. Each image is reconstructed within 200 msec of acquisition, and the FC magnitude image is displayed in gray-scale format. The phase difference between the reconstructed FC and FE images, a difference proportional to velocity along the flow-encoding direction, is encoded in color and superimposed on the gray-scale FC image. Magnitude and phase information are thus presented simultaneously. The viewer may interactively adjust many acquisition parameters during data acquisition. Experimental results of phantom and in vivo human studies validate the method. Characteristics of the color flow MR imaging technique are compared with those of duplex color ultrasound.     

Reperfused and nonreperfused myocardial infarction: diagnostic potential of Gd-DTPA--enhanced MR imaging

Forty-five patients with suspected acute myocardial infarction were examined with magnetic resonance (MR) imaging before and serially up to 30 minutes after intravenous injection of gadolinium diethylenetriaminepentaacetic acid (DTPA), 0.1 mmol/kg of body weight. Coronary angiography after thrombolytic therapy was performed in all patients to assess reperfusion. Intensity ratios between both reperfused and nonreperfused infarcted areas and normal myocardium increased significantly up to 15-20 minutes after administration of Gd-DTPA and were still elevated 30 minutes after injection (P less than .0001). In accordance with the findings in experimental studies, four distribution patterns of infarct enhancement were observed. The overlap in enhancement patterns and similar maximal intensity ratios after Gd-DTPA administration for both reperfused and nonreperfused infarcts preclude a reliable differentiation on the basis of these factors alone. Significant enhancement of both reperfused and nonreperfused infarcts allows adequate infarct imaging up to at least 30 minutes after administration of Gd-DTPA.     

Paranasal sinuses: CT imaging requirements for endoscopic surgery

Recent advances in the understanding of mucociliary activity and the pathophysiology of the nasal cavity and paranasal sinuses have revolutionized the surgical management of chronic and/or recurrent sinusitis. Meticulous radiographic delineation of the small structures in this region, coupled with endoscopic evaluation, provides detailed preoperative information regarding morphology and pathology. This information has led to more focused endoscopic surgical procedures, which have dramatically reduced patient morbidity. As a consequence, there is now worldwide interest among otolaryngologists in the radiologic definition of paranasal regional anatomy. For effective interactions between radiologist and otolaryngologist, the former must be prepared to render interpretations that address these "microanatomic" locales. This communication is directed at familiarizing the radiologist with these observations and concepts, considering both normal and disturbed anatomy with their attendant pathophysiologic and therapeutic implications.