Diagnosing pulmonary embolism. Indeed, when will we ever learn?
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Biomedical subjects
Publications and source records attributed to H L Magill.
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Aggressive cardiac revascularization requires recognition of stunned and hibernating myocardium, and cost considerations may well govern the technique used. Dynamic low-dose (1 mCi) [123I]iodophenylpentadecanoic acid (IPPA) metabolic imaging is a potential alternative to PET using either 18FDG or 15O-water. Resting IPPA images were obtained from patients with severe ischemic cardiomyopathy, and transmural myocardial biopsies were obtained during coronary bypass surgery to confirm viability. Thirty-nine of 43 (91%) biopsies confirmed the results of the IPPA images with a sensitivity for viability of 33/36 (92%) and a specificity of 6/7 (86%). Postoperatively, wall motion improved in 80% of IPPA-viable, dysfunctional segments. Furthermore, when compared to reinjection thallium (SPECT-TI) scans after myocardial infarction, IPPA-SPECT-TI concordance occurred in 27/35 (77%) (K = 0.536, p = 0.0003). Similar to PET, IPPA demonstrated more viability than SPECT-TI, 26/35 (74%) versus 18/35 (51%) (p = 0.047). Metabolic IPPA cardiac viability imaging is a safe, inexpensive technique that may be a useful alternative to PET.
OBJECTIVE: The null hypothesis is that active labor is a more important factor with regard to both timing and progression of periventricular-intraventricular hemorrhage than is route of delivery. Infants delivered by cesarean section after entering the active phase of labor will behave in a manner similar to that of previously studied infants delivered vaginally as to when periventricular-intraventricular hemorrhage occurs and frequency of progression. STUDY DESIGN: The 106 infants of 85 women delivered by cesarean section were the subjects of this study. Forty-six infants were in the no-labor group, 33 in the latent-phase labor group, and 27 in the active-phase labor group. Head ultrasonographic examinations were performed at delivery, at 1, 6, 12, and 24 hours, and then daily for the first 7 days of life. Continuous variables were compared by one-way analysis of variance among those infants with no hemorrhage or with periventricular-intraventricular hemorrhage. Categoric variables were compared by chi 2 analysis and Fisher's exact test when appropriate. A p value of less than 0.05 was considered significant. RESULTS: There was no difference in the frequency of early hemorrhage (less than or equal to 1 hour of age), late hemorrhage (greater than 1 hour of age), or overall periventricular-intraventricular hemorrhage in the infants not in labor, in latent-phase labor, or in active-phase labor at the time of cesarean section. However, the frequency of grade 3 or 4 hemorrhage and the progression of hemorrhage were significantly higher in the infants whose mothers had an active phase of labor compared with infants whose mothers had no labor or did not progress beyond the latent phase. Infants who had early periventricular-intraventricular hemorrhage (less than or equal to 1 hour of age) also had a higher frequency of progression of hemorrhage. CONCLUSIONS: Cesarean section before the active phase of labor does not change the overall frequency of hemorrhage but results in a lower frequency of progression to grade 3 or 4 hemorrhage. We do not feel that these data support performing more cesarean sections for preterm delivery as a method of preventing progression of periventricular-intraventricular hemorrhage in the preterm infant.
The scintigraphic appearance of an overuse injury at the insertion of the iliotibial band is described. This injury was depicted on three-phase bone scintigraphy as focally increased radionuclide concentration in the anterolateral tibial condyle (lateral tibial tubercle) where the iliotibial band inserts. Overuse injuries involving the insertion of the iliotibial band are uncommon and are not to be confused with a stress fracture or other bony lesion involving the lateral tibial condyle.
Hypophosphatasia, a rare heritable form of rickets/osteomalacia, is characterized by deficient activity of the tissue nonspecific (liver/bone/kidney) isoenzyme of alkaline phosphatase (ALP). Signs may be present prenatally or not until late adult life. Although the infantile form of hypophosphatasia has usually been categorized as an autosomal recessive (AR) disorder, several studies suggest that childhood cases are the consequence of either AR or autosomal dominant (AD) inheritance and adult cases are primarily AD. Eastman and Bixler (J Craniofac Genet Dev Biol 3:213-234, 1983) propose that all cases of hypophosphatasia may reflect AD inheritance with 85% penetrance and homozygous lethality. We report on 3 patients with hypophosphatasia in a black family, first manifested clinically during infancy, where the pattern of inheritance for each is consistent with AR transmission. Two were brothers who died from the disorder. The other patient, a cousin, presented with classic stigmata of hypophosphatasia during infancy, but is now age 5 1/2 years and has had a much milder clinical course. Although consanguinity is absent, the maternal grandmothers are sibs as are the maternal grandfathers and the paternal grandmothers. The family history is otherwise negative for skeletal or dental disease. Laboratory and radiographic results are consistent with heterozygosity in each parent. Fibroblast ALP activity is less than 1% normal in all 3 patients with no complementation observed in heterokaryon analysis. Accordingly, the genetic defects appear to be identical in all 3 patients. Our findings show that infantile hypophosphatasia may be inherited as an AR condition where there is variable expressivity and that homozygosity or compound heterozygosity, as may be the case in this family, is not necessarily lethal.
The radiologic, CT, MR, and histological features of a case of chondrosarcoma of the femur presenting in childhood are reported. This case emphasizes the use of correlative imaging in establishing the diagnosis as well as the value of MR supplemented by Gadolinium-DTPA enhancement in disclosing abundant necrosis within the tumor.
The association between periventricular-intraventricular hemorrhage (PV-IVH) and frequent handling resulting from various neonatal intensive care procedures and routine interventions was evaluated in a prospective clinical study. Inborn premature babies with birth weight less than or equal to 1500 gm (n = 156) who did not have PV-IVH or who had grade 1 PV-IVH at less than or equal to 1 hour were randomly assigned to the reduced manipulation protocol (n = 62) or to standard care (n = 94). A bedside microcomputer-based data acquisition system was used to monitor the duration of rest or the number of interventions per day. Infants assigned to receive reduced manipulation spent a significantly higher percentage of time each day at rest than did those who received standard manipulation (p less than 0.006). However, the incidence of grades 2 to 4 PV-IVH did not differ significantly (30% in the study vs 37% in the standard manipulation group). When we analyzed the effect of manipulation in relation to risk of PV-IVH, while taking into account other perinatal variables, standard manipulation was not associated with increased risk of grades 2 to 4 PV-IVH. However, low birth weight, maternal smoking, general anesthesia, early grade 1 PV-IVH, low hematocrit, lowest arterial oxygen pressure within the first 6 hours of life, and large base deficit at 6 hours of age all increased the relative risk of grades 2 to 4 PV-IVH.
Bedside microcomputer-derived, minute-to-minute mean arterial pressure (MAP) values during the first 48 hours of life were studied in 100 preterm babies with birth weight less than or equal to 1500 gm. In those babies (n = 72) with no periventricular-intraventricular hemorrhage (PV-IVH) or with grade 1 PV-IVH, the MAP values increased during the study period, with minute-to-minute variation and interval undulation. The MAP values in those with birth weight greater than 1000 gm were higher than in those of lower birth weight. Infants in whom grades 2 to 4 PV-IVH developed (n = 28) had consistently lower MAP values during the study period. Minute-to-minute variability, expressed as the average of the coefficients of variation at 15-minute intervals, did not differ between birth weight groups, nor did they differ between the PV-IVH group and their matched control subjects. However, those with PV-IVH spent a greater percentage of time, with a coefficient of variation greater than or equal to 13% or less than 3%, than their matched control subjects spent (p less than 0.005). This study provides reference data for MAP changes in premature babies. The observed MAP changes in those with PV-IVH lend support to a significant role for MAP alterations in the pathogenesis of PV-IVH.
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While avid accumulation of gallium-67 citrate and technetium-99m methylene diphosphonate (MDP) occurs initially in most cases of primary Ewing sarcoma, uptake after therapy is less well defined. Thirty patients with Ewing sarcoma who underwent Ga-67 and bone scintigraphy at diagnosis, at completion of therapy, and at relapse from 1978 to 1988 were evaluated. All 30 patients showed less primary site Ga-67 activity following therapy. Twenty-three of 28 patients who underwent corresponding bone scintigraphy showed less uptake, but residual activity was usually more intense than with Ga-67. Avid reaccumulation of Ga-67 occurred in four of five patients with primary site relapse, while patients who underwent bone scintigraphy showed less change. It was concluded that a greater decrease in Ga-67 than in Tc-99m MDP uptake often occurs in patients successfully treated for primary Ewing sarcoma. Information obtained at Ga-67 scintigraphy is most likely to be helpful if results of bone scintigraphy remain abnormal or if occult relapse is suspected.
Dipyridamole TI-201 imaging is an ideal alternative to exercise TI-201 scintigraphy in patients who are unwilling or unable to perform maximum exercise stress. The use of intravenous dipyridamole, alone or in combination with exercise, has not been approved for clinical practice by the Food and Drug Administration. Once approval is granted, the test will become a widely used and important component of the cardiac work-up. The indications, methodology, side effects, and utility of dipyridamole cardiac imaging in the clinical setting are discussed and a variety of examples presented.
Variation in skin-to-kidney center distance has been shown to have a significant influence on quantification of renal function with the gamma camera. Several techniques to compensate for this variability have been proposed in adults, yet it has been suggested that depth correction is not necessary for quantitative renography in children. Skin-to-kidney center distances were measured from computed tomograms in 53 supine pediatric patients. Nearly 40% of the kidneys examined varied more than 1 cm from the average renal depth, and 8% deviated more than 2 cm. Right kidney depth differed from left kidney depth by more than 1 cm in less than 10% of the patients. Measurements were in agreement with regression equations based on lateral scintigraphy in children, but were consistently underestimated by nomograms developed for skin-to-kidney center distance in adults. Failure to recognize interindividual variability in skin-to-kidney center distance can introduce significant errors in quantitative pediatric renography.