Operative vaginal delivery and midline episiotomy: a bad combination for the perineum

OBJECTIVE

The purpose of this study was to determine the impact of operative vaginal delivery (forceps or vacuum) and midline episiotomy on the risk of severe perineal trauma.

STUDY DESIGN

In this retrospective cohort study, we assessed the impact of maternal and obstetric factors on the risk of development of severe perineal trauma (third- and fourth-degree perineal lacerations) for all singleton, vertex vaginal live births (n = 33,842) between 1996 and 2003.

RESULTS

Among nulliparous women, 12.1% had operative vaginal delivery, 22.4% had midline episiotomy, and 8.1% experienced severe perineal trauma. Among multiparous women, 3.4% had operative vaginal delivery, 4.2% had midline episiotomy, and 1.2% experienced severe perineal trauma. Controlling for maternal age, ethnicity, birth weight and head circumference, evaluation of the interaction of episiotomy and delivery method revealed that forceps (nulliparous women: odds ratio [OR] 8.6, 95% CI 6.5-10.7; multiparous women: OR 26.3, 95% CI 18.1-34.5) and episiotomy (nulliparous women: OR 4.5, 95% CI 3.7-5.4; multiparous women: OR 14.6, 95% CI 10.4-20.5) were consistently associated with the increased risk of anal sphincter trauma. In fact, the magnitude of effect of the statistically significant synergistic interaction was evidenced by more than 3-fold excess of risk of using operative vaginal delivery alone.

CONCLUSION

The use of operative vaginal delivery, particularly in combination with midline episiotomy, was associated with a significant increase in the risk of anal sphincter trauma in both primigravid and multigravid women. Given the reported substantial long-term adverse consequences for anal function, this combination of operative modalities should be avoided if possible.

Sildenafil citrate and fetal outcome in pregnant rats

OBJECTIVE

To determine the effects of sildenafil citrate on fetal growth in maternal rats exposed to hypoxia.

METHODS

Timed pregnant rats were randomized to either hypoxia or control on gestational days (GD) 18-20, and received either sildenafil (45 mg/kg) orally every 12 h on GD 18-21 or an equal volume of sterile water. Fetal pups were retrieved by laparotomy on GD 21. Pup weight and length were evaluated and cGMP measured in maternal and fetal blood.

RESULTS

In the non-hypoxic rats, sildenafil exposure was associated with a decrease in size(4.75 +/- 0.43 vs. 5.11 +/- 0.34 g, p = 0.00). In contrast, in the hypoxic rat model, sildenafil exposure was associated with increased size of the offspring (5.48 +/- 0.45 vs. 5.16 +/- 0.36 g, p = 0.016). Maternal cGMP levels were increased in the presence of both sildenafil and hypoxia (23.0 +/- 10.5 vs. 15.6 +/- 2.7 pmol/ml, p = 0.001).

CONCLUSION

Exposure to sildenafil in a non-hypoxic setting results in a decrease in fetal size. Sildenafil in the presence of a stimulus, hypoxia, will lead to increased fetal size. These results suggest that sildenafil may have some influence on fetal growth. How these effects occur and by what mechanism remain to be determined.

Demonstration and characterization of a detector for minimally destructive detection of Bose condensed atoms in real time

We present the first detector that is capable of recording high-bandwidth atom number density measurements of a Bose-Einstein condensate, with a readout of the data in real time. It is based on a shot-noise-limited unbalanced Mach-Zehnder interferometer designed for a minimally destructive measurement of the atom column density of a Bose-Einstein condensate. The shot-noise limit is reached by phase modulating the laser in one arm and phase locking the interferometer with a second-color laser. The detector is characterized, and its sensitivity for a fractional change in the column density of a Bose-Einstein condensate is calculated. With this detection system it may be possible to implement feedback to stabilize a Bose-Einstein condensate or an atom laser.

Cyclooxygenase inhibitors and the exercise-induced stress response

Objective. This study investigated the effects of single dosages of the non-steroidal anti-inflammatory drug (NSAID) naproxen, and of the coxib, rofecoxib, on the exercise-induced stress response. Design. Eight subjects (age 20.9 ± 1.1 years, weight 70.4 ± 3.9 kg, height 170.9 ± 6.7 cm, body surface area 1.82 ± 0.09 m2, body mass index 24.1 ± 1.3 kg.m-2) took part in a double-blind, drug-placebo, cross-over design study. The experimental procedures were performed on 3 occasions on each volunteer, i.e. once on placebo, once on naproxen (single dose of 1 000 mg) and once on rofecoxib (single dose of 50 mg). Results. Mean post-exercise cortisol values were significantly higher than pre-exercise values with the subjects on placebo (p = 0.0365) and rofecoxib (p = 0.0208), but not on naproxen (p = 0.0732). Post-exercise oral temperatures were significantly higher than pre-exercise temperature values on placebo (p = 0.0153) and rofecoxib (p = 0.0424), but not on naproxen (p = 0.5444). Conclusion. The results of this study suggest a role for cyclooxygenase-1 (COX-1) in the exercise-induced cortisol and temperature response to exercise. South African Journal of Sports Medicine Vol. 18 (1) 2006: pp. 4-8

Seroprevalence of Bordetella pertussis antibodies in mothers and their newborn infants

BACKGROUND: Pertussis is a highly communicable, vaccine-preventable respiratory disease. Although the largest number of reported cases is among young infants, the most rapidly increasing incidence in the USA is in adolescents and young adults. Importantly, adult family members are the likely major reservoir, infecting susceptible infants before completion of childhood vaccination. We studied maternal-neonatal paired blood samples for the presence of pertussis-related antibodies to assess level of immunity and passive transplacental antibody passage. METHODS. Unselected maternal-neonatal cord blood samples were collected from 101 term deliveries in a single urban uninsured/underinsured hospital setting. Sera were analyzed for anti-pertussis toxin (PT), filamentous hemagglutinin (FHA) and pertactin (PRN) IgG antibodies by enzyme-linked immunosorbent assay (ELISA). Antibody titers were calculated using reference line methodology. Antibody values were log-transformed to establish geometric mean titers (GMT) for analysis. Student's t-test, Mann-Whitney, Pearson correlation and chi square were used for statistical comparisons as appropriate. RESULTS. Mean (SD) maternal age, gestational age and birth weight were 26.8 (6.8) years, 38.9 (1.4) weeks and 3239 (501) g, respectively. Detectable maternal levels of anti-PT, FHA and PRN were found in 34.7%, 95.0% and 80.2%, respectively. Maternal GMT (SD) for PT, FHA and PRN were 4.4 (2.6), 26.6 (3.1) and 12.3 (2.9), respectively. There was no significant relationship between PT, FHA or PRN detection or antibody GMT and maternal age. Maternal anti-PT, FHA and PRN were highly correlated with neonatal cord blood values. CONCLUSION: Despite previous childhood immunization, a large number of parous women have low or undetectable pertussis-related antibody levels, suggesting susceptibility to infection. Even with efficient transplacental passage of these antibodies, neonates similarly have limited measurable protection as detected by cord blood sampling. These data support the need for adolescent or adult vaccination against Bordetella pertussis. Healthcare providers and their clients should be aware of the risk for infant infection via family member transmission.

Use of over-the-counter medications and herbal remedies in pregnancy

The purpose of this study was to determine the frequency of prescription and over-the-counter (OTC) medications, and herbal remedies used by pregnant women. A prospective observational study was performed at a single tertiary-care hospital. Postpartum women completed a questionnaire that included a list of more than 120 medications, herbal remedies, and alternative therapies listed by both brand and common name. Patients were asked to identify any and all medications or treatments used during pregnancy. Of 418 patients who completed questionnaires, 96.9% took at least one medication during their pregnancy. After excluding prenatal vitamins and iron supplements, 76.5% took at least one other medication; 62.8% used OTC medications, and 4.1% used herbal and/or alternative remedies. Multiple drug use occurred in 33.5% of patients, with up to 13.6% consuming four or more medications. The use of prescribed and OTC, medications, and herbal/alternative therapy, is common in pregnancy, with many patients consuming more than one agent at a time.

Antecubital vein venous sampling does not distort circulating levels of peptide and sex steroid hormones

Simultaneous sampling from the antecubital vein (ACV) and a heated superficial hand vein (HSHV) at 10-minute intervals was performed in 6 women for determination of glucose, insulin, luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin, estradiol (E2), progesterone (P4), testosterone (T), and dehydroepiandrosterone sulfate (DHEAS). Strong correlations were identified for each parameter between the two vessels, with luteinizing hormone (LH) and follicle-stimulating hormone (FSH) pulse patterns nearly superimposable between antecubital vein (ACV) and superficial hand vein (HSHV) samples.

Effects of the mutation R145G in human cardiac troponin I on the kinetics of the contraction-relaxation cycle in isolated cardiac myofibrils

Familial hypertrophic cardiomyopathy (FHC) has been linked to mutations in sarcomeric proteins such as human cardiac troponin I (hcTnI). To elucidate the functional consequences of the mutation hcTnI(R145G) on crossbridge kinetics, force kinetics were analysed in murine cardiac myofibrils carrying either the mutant or the wild-type protein. The mutation was introduced into the myofibrils in two different ways: in the first approach, the endogenous Tn was replaced by incubation of the myofibrils with an excess of reconstituted recombinant hcTn containing either hcTnI(WT) or hcTnI(R145G). Alternatively, myofibrils were isolated either from non-transgenic or transgenic mice expressing the corresponding mcTnI(R146G) mutation. In myofibrils from both models, the mutation leads to a significant upward shift of the passive force-sarcomere length relation determined at pCa 7.5. Addition of 5 mm BDM (2,3-butandione-2-monoxime), an inhibitor of actomyosin ATPase partially reverses this shift, suggesting that the mutation impairs the normal function of cTnI to fully inhibit formation of force-generating crossbridges in the absence of Ca(2)(+). Maximum force development (F(max)) is significantly decreased by the mutation only in myofibrils exchanged with hcTnI(R145G) in vitro. Ca(2)(+) sensitivity of force development was reduced by the mutation in myofibrils from transgenic mice but not in exchanged myofibrils. In both models the rate constant of force development k(ACT) is reduced at maximal [Ca(2)(+)] but not at low [Ca(2)(+)] where it is rather increased. Force relaxation is significantly prolonged due to a reduction of the relaxation rate constant k(REL). We therefore assume that the impairment in the regulatory function of TnI by the mutation leads to modulations in crossbridge kinetics that significantly alter the dynamics of myofibrillar contraction and relaxation.

Expression of transforming growth factor-beta and extracellular matrix by human peritoneal mesothelial cells and by fibroblasts from normal peritoneum and adhesions: effect of Tisseel

We have previously shown that fibroblasts obtained from adhesions produce greater amounts of transforming growth factor-beta 1 (TGF-beta1) and extracellular matrix (ECM) molecules than normal fibroblasts isolated from normal peritoneum. The purpose of the current studies was to examine the effect of Tisseel (Baxter Healthcare Corporation, Glendale, CA), a fibrin sealant containing fibrinogen, aprotinin (a protease inhibitor), thrombin, and CaC1(2), on TGF-beta1 and ECM production by human peritoneal mesothelial cells, normal peritoneal fibroblasts, and adhesion fibroblasts. Multiplex reverse transcription-polymerase chain reaction using beta-actin as a housekeeping gene was used to determine mRNA levels of TGF-beta1 and ECM in these cells at 6, 12, 24, and 48 hours under normoxic conditions in the following treatment groups : fibrin sealant (Tisseel) alone; fibrin sealant with the two components diluted 1 : 2; fibrin sealant with the sealer protein component reconstituted without aprotinin (a protease inhibitor); fibrin sealant with the sealer protein component reconstituted without aprotinin (and both components diluted 1 : 2); fibrin sealant components diluted to physiologic concentrations; and control (culture media). The test compositions had little effect on TGF-beta1 mRNA expression in mesothelial cells and normal peritoneal fibroblasts, but resulted in a marked reduction of TGF-beta1 from adhesion fibroblasts. Expression of type I collagen by human peritoneal mesothelial cells was not detected; the compositions reduced type I collagen mRNA expression by both types of fibroblasts. Type III collagen was detected at six hours, and increased approximately 50 percent by culturing for 48 hours. Tisseel at full strength and with both components diluted 1 : 2 initially increased type III collagen mRNA levels; in contrast, type III collagen mRNA levels were reduced in mesothelial cells by the fibrin sealant without aprotinin at both concentrations and at physiologic concentrations. In both types of fibroblasts, the Tisseel compositions reduced type III collagen mRNA expression. Fibronectin mRNA were transiently reduced at six hours by approximately 50 percent in the presence of the Tisseel components, but then returned to control levels. Fibronectin mRNA levels were not altered in normal peritoneal fibroblasts, but were reduced by all but the physiologic concentration in adhesion fibroblasts. Tisseel may modulate human peritoneal mesothelial cell, normal peritoneal fibroblast, and adhesion fibroblast function. These results suggest that fibrin sealant prepared from the Tisseel kit without aprotinin has the ability to reduce ECM and TGF-beta1 mRNA levels, especially from adhesion fibroblasts, which may indicate a role in reduction of postoperative adhesion development.

An Improved Method for Predicting Which Heavy Drinkers Become Intoxicated

Not all heavy drinkers become intoxicated. We sought to improve predictability of intoxication of heavy drinkers. Based on criteria for heavy drinking in the National Household Survey on Drug Abuse (NHSDA), we identified characteristics related to heavy drinking. We then created a dichotomous heavy drinker typology variable (yes/no) and determined how well we were able to identify drinkers who became intoxicated at least twice a month. Of those who fit this heavy drinking profile, 54% drank regularly to the point of intoxication, the same percent as those who become intoxicated in the self-reported heavy drinking group. However, 77% of those who fit both the profile and were self-described heavy drinkers, drank regularly to intoxication. We concluded that a demographic typology combined with self-reported drinking improves predictability of intoxication in heavy drinkers, and is a promising direction for research.

Effect of Tisseel® on expression of tissue plasminogen activator and plasminogen activator inhibitor-1

OBJECTIVE

To examine the effect of fibrin sealant on mRNA expression of factors regulating plasminogen activator activity in human peritoneal cells. Plasminogen activator activity is thought to play a pivotal role in degradation of the proteinaceous mass that develops after surgical procedures. Reduction of plasminogen activator activity, as occurs with tissue trauma, results in increased postoperative adhesion development.

DESIGN

Tissue culture for 6, 12, 24, and 48 hours.

SETTING

University research laboratory.

PATIENTS

Source of mesothelial cells with fibroblasts.

INTERVENTION(S)

Measurement of mRNA expression of tissue plasminogen activator (t-PA) and plasminogen activator inhibitor 1 (PAI-1).

MAIN OUTCOME MEASURE(S)

Multiplex reverse transcriptase/polymerase chain reaction (RT/PCR) was used to determine relative change in t-PA and PAI-1 mRNA levels under six conditions: [1]. fibrin sealant (Tisseel); [2]. fibrin sealant (Tisseel) two components diluted 1:2; [3]. fibrin sealant (Tisseel) sealer protein component reconstituted without aprotinin (a protease inhibitor); [4]. fibrin sealant (Tisseel) sealer protein component reconstituted without aprotinin, both components diluted 1:2; [5]. fibrin sealant (Tisseel) components diluted to physiologic concentrations; and [6] control (culture media).

RESULTS

The mRNA levels of t-PA and PAI-1 by human peritoneal cells were unchanged during 48 hours. In mesothelial cells, the addition of the compositions increased t-PA mRNA levels. A selective increase was observed in the normal peritoneal fibroblasts at the later time points; similar increases were identified in adhesion fibroblast cultures. In mesothelial cells, the more concentrated compositions generally increased PAI-1 mRNA above control levels, whereas in normal peritoneal fibroblasts PAI-1 levels generally remained unchanged. In contrast, in adhesion fibroblasts, PAI-1 levels decreased over time with treatment.

CONCLUSION(S)

Fibrin sealant, in the presence and absence of aprotinin, increases both t-PA and PAI-1 expression by human peritoneal cells; changes not seen with physiologic concentrations of fibrin sealant. These observations suggest that in addition to its ability to help achieve hemostasis, fibrin sealant affects the healing process by altering components of the plasminogen activator system, which may be of benefit in the reduction of postoperative adhesions.

Effect of gonadotropin-releasing hormone hypogonadism on insulin action as assessed by hyperglycemic clamp studies in men

OBJECTIVE

To investigate the effects of decreasing androgen levels on insulin action, in view of the relationship between hyperandrogenism and impaired insulin action in women with polycystic ovary syndrome.

DESIGN

Prospective, clinical study.

SETTING

University hospital.

PATIENT(S)

Ten normal healthy men.

INTERVENTION(S)

Gonadotropin-releasing hormone (GnRH) agonist, 3.75 mg, administered monthly for 3 months.

MAIN OUTCOME MEASURE(S)

Insulin action (M/I ratio).

RESULT(S)

The M/I ratio decreased from 0.24 +/- 0.04 to 0.17 +/- 0.04 after GnRH agonist therapy.

CONCLUSION(S)

In normal men, administration of a GnRH analogue was associated with a decrease in both testosterone levels and insulin action.

Regulation of expression of tissue plasminogen activator and plasminogen activator inhibitor-1 by dichloroacetic acid in human fibroblasts from normal peritoneum and adhesions

OBJECTIVE

As part of our ongoing studies to understand the biologic mechanisms of wound repair that lead to postoperative adhesions, we have identified characteristics of an adhesion phenotype that differs between fibroblasts that are obtained from human normal peritoneum and adhesions. In this study, we sought to examine whether stimulation of aerobic metabolism would alter differential expression of tissue plasminogen activator and plasminogen activator inhibitor-1, thereby creating a milieu likely to be less favorable to postoperative adhesion development. To examine this issue, we used a compound, dichloroacetic acid, that stimulates the pyruvate dehydrogenase complex, which causes pyruvate to be metabolized in the Kreb's cycle rather than being converted into lactate, thereby switching anaerobic to aerobic metabolism.

STUDY DESIGN

Human fibroblasts from normal peritoneum and adhesions were cultured in the absence or presence of dichloroacetic acid (100 microg/mL) for 24 hours, under normal and hypoxic (2% O(2)) conditions. Real-time reverse transcriptase-polymerase chain reaction of tissue plasminogen activator, plasminogen activator inhibitor-1, and a housekeeping gene beta-actin was performed with messenger RNA that was extracted from all treatment points.

RESULTS

Dichloroacetic acid stimulated normal peritoneal fibroblast tissue plasminogen activator messenger RNA expression under hypoxic conditions. In adhesion fibroblasts, dichloroacetic acid treatment enhanced tissue plasminogen activator messenger RNA expression under both normoxic and hypoxic conditions. Plasminogen activator inhibitor-1 messenger RNA expression was unaltered by dichloroacetic acid in normoxic normal peritoneal fibroblasts; but during culture under hypoxic conditions, dichloroacetic acid reduced plasminogen activator inhibitor-1 messenger RNA expression. Similarly, in adhesion fibroblasts, dichloroacetic acid reduced plasminogen activator inhibitor-1 messenger RNA expression under both normoxic and hypoxic conditions. As a result, in normal peritoneal fibroblasts under hypoxic conditions and in adhesion fibroblasts under normoxic and hypoxic conditions, dichloroacetic acid greatly increased the tissue plasminogen activator/plasminogen activator inhibitor-1 ratios.

CONCLUSION

These findings confirm that fibroblasts from adhesions are characterized by reduced tissue plasminogen activator and increased plasminogen activator inhibitor-1 production. These observations are extended to show the stimulation of oxidative metabolism by dichloroacetic acid increases tissue plasminogen activator expression under hypoxic conditions. Dichloroacetic acid reduces plasminogen activator inhibitor-1 production by hypoxic normal peritoneal fibroblasts and adhesion fibroblasts under hypoxic conditions. The resultant increases in the tissue plasminogen activator/plasminogen activator inhibitor-1 ratios would favor the development of a fibrinolytic milieu, which would be expected potentially to limit postoperative adhesion development. Thus, regulation of metabolic activity of peritoneal cells may provide a target for future interventions for the reduction of the development of postoperative adhesions, particularly as intervention relates to the healing of peritoneal sites that previously had adhesions. (eg, sites of potential adhesion reformation).

Effects of oxidized regenerated cellulose on the expression of extracellular matrix and transforming growth factor-beta1 in human peritoneal fibroblasts and mesothelial cells

OBJECTIVE

The purpose of this study was to evaluate the potential biologic effects of oxidized regenerated cellulose, which has been shown in multiple human in vivo studies to reduce postoperative adhesion development, on the messenger RNA levels of transforming growth factor-beta1, type I collagen, type III collagen, and fibronectin.

STUDY DESIGN

The oxidized regenerated cellulose was dissolved in saline solution and added to confluent, monolayer cultures of human normal fibroblasts and mesothelial cells. Control cells were maintained in media alone at the same pH. After 24 hours of treatment, total RNA was extracted from all cells. Real-time reverse transcription-polymerase chain reaction was performed to determine the relative change in messenger RNA levels of type I, type HI collagen, fibronectin, transforming growth factor-beta1, and beta-actin (housekeeping gene) in response to the oxidized regenerated cellulose treatment (n=4 cultures). Student t tests were performed for each cell type, which compared oxidized regenerated cellulose-treated cells to control cells. Calculated power for the statistically significant findings ranged from 65% to 100%.

RESULTS

Transforming growth factor-beta1 messenger RNA was elevated by the oxidized regenerated cellulose treatment in the mesothelial cells by 13% (control cells, 0.562+/-0.022; oxidized regenerated cellulose-treated cells, 0.636+/-0.014; P=.03). In normal fibroblasts, transforming growth factor-beta1 messenger RNA was slightly, but not significantly, decreased in oxidized regenerated cellulose-exposed normal fibroblasts compared with controls (control cells, 0.622+/-0.062; oxidized regenerated cellulose-treated cells, 0.609+/-0.006; P=.85). Type I collagen was found to be increased by exposure to oxidized regenerated cellulose in both mesothelial cells and normal peritoneal fibroblasts. Type I collagen was increased by 23% in mesothelial cells (control cells [0.587+/-0.018] vs oxidized regenerated cellulose-treated cells [0.722+/-0.010], P=.002), and 27% in normal fibroblasts (control cells, 0.522+/-0.018, oxidized regenerated cellulose-treated cells, 0.665+/-0.009; P=.001). However, messenger RNA levels of type III collagen and fibronectin (other representative molecules of the extracellular matrix) were not altered significantly by oxidized regenerated cellulose application in vitro.

CONCLUSION

Oxidized regenerated cellulose influences the expression of factors that are accepted commonly to be associated with adhesiogenesis. Oxidized regenerated cellulose increased the expression of transforming growth factor-beta1 in mesothelial cells and type I collagen in mesothelial cells and normal peritoneal fibroblasts. Minimization of these oxidized regenerated cellulose-induced molecular changes, if they occur in vivo, may improve the ability of oxidized regenerated cellulose to reduce postoperative adhesion development.

Values of fasting glucose levels, glucose tolerance tests, and glucose-insulin ratios as predictors of glucose tolerance

OBJECTIVE

To examine the ability to use parameters obtainable from an oral glucose tolerance test to predict insulin action as determined under hyperinsulinemic, hyperglycemic conditions.

DESIGN

Prospective clinical investigation.

SETTING

University medical center clinical research unit.

PATIENT(S)

Healthy male volunteers.

INTERVENTION(S)

Oral glucose tolerance test and hyperglycemic (+125 mg/dL) clamp studies.

MAIN OUTCOME MEASURE(S)

Glucose and insulin (I) levels, rate of glucose uptake (M) under hyperglycemic conditions, and M/I ratios.

RESULT(S)

Among individuals with normal glucose tolerance, as assessed by an oral glucose tolerance test, the fasting insulin level is the glucose tolerance test parameter that correlates best with insulin action during a hyperglycemic clamp.

CONCLUSION(S)

Measurement of fasting serum insulin levels in conjunction with an oral glucose tolerance test improves the ability to assess insulin action. Such combinations may improve the ability to diagnose insulin-resistant states.

Cephalometric analysis with digital storage phosphor images: extreme low-exposure images with and without postprocessing noise reduction

This study evaluated extreme exposure reduction in cephalography with monitor-displayed DICOM (Digital Imaging and Communication in Medicine, Rosslyn, Va) images. The purposes were to investigate to what extent exposure can be reduced without losing diagnostic information for tracing analysis, whether postprocessing noise reduction could benefit localization of anatomic landmarks in extreme low-exposure images, and the quality of the images. Three images (optimal, extreme low exposure, and noise-reduced extreme low exposure) were obtained from 24 volunteers. Three orthodontists traced 18 landmarks and subjectively judged the quality of the images. Sixteen of the landmarks were well identified on the extreme low-exposure images when they were compared with the optimal images. Apex inferius and apex superius were not well identified. The evaluation of image quality on a visual analogue scale showed that the optimal images were given the highest scores, extreme low-exposure images with postprocessing noise reduction the second highest scores, and extreme low-exposure images the lowest scores. Monitor-based tracing analysis on storage phosphor cephalographic images with a 94% exposure reduction, compared with conventional exposure, can be performed with only 2 of 18 landmarks not well identified. The landmarks were better identified on the low-exposure images with standard postprocessing than on the images with post-processing noise reduction, although the subjective evaluation of the image quality indicated the opposite.