Population-based study of herpes zoster and its sequelae.

The epidemiology of herpes zoster and its sequelae have been investigated in a community-based study. The incidence rates observed in Rochester, Minnesota, are lower than those determined in practice-based series; and this may reflect some selectivity in practice-based series compared to population-based studies. No significant sex difference or seasonal variation was observed but the incidence did increase markedly with age. An increase in incidence was also observed over the 15-year period studied. The dermatomal distribution of herpes zoster observed in Rochester was quite similar to previous studies, despite their inherent biases in case ascertainment, except for a lower proportion with cranial nerve zoster. Herpes ophthalmicus (V1) appears to affect a slightly different population than zoster of the other dermatomes, with elderly males being more at risk. Also, herpes ophthalmicus is associated with a higher complication rate compared to the other dermatomes primarily due to the fragility of the involved organ. The elderly are also at greatest risk for the most common complication, post-herpetic neuralgia. The rate of PHN is not significantly increased in any particular dermatome but is significantly decreased in lumbar herpes zoster.

Epidemiologic investigation of the association between herpes zoster and multiple sclerosis.

The apparent association between MS and herpes zoster reported in the literature was investigated in a community-based epidemiologic study. Five hundred ninety residents of Rochester, Minnesota, diagnosed with herpes zoster from 1945 through 1959 were followed 9,389 person-years for onset of MS. No cases were observed, whereas 0.2 case was expected, using Rochester incidence rates for MS. Calculation of the power of this study indicated that approximately 200,000 person-years of follow-up of herpes zoster patients is necessary in order to detect a threefold increase in incidence of MS with 85% probability. Conversely, 48 Rochester residents diagnosed with MS were followed for 860 person-years for subsequent onset of herpes zoster. Three cases were observed, whereas 1.8 cases were expected for a relative risk of 1.7, which is not significantly different from unity.

Bilateral reexpansion pulmonary edema following unilateral pleurocentesis.

Acute ipsilateral pulmonary edema following reexpansion of the lung after pleurocentesis or pneumothorax is a well described entity. We report the unusual occurrence of bilateral pulmonary edema following unilateral pleurocentesis in a young male without heart disease. Various hypotheses regarding the mechanism of reexpansion pulmonary edema include increased capillary permeability due to hypoxic injury, decreased surfactant production, altered pulmonary perfusion and mechanical stretching of membranes. This case suggests that forces leading to ipsilateral reexpansion pulmonary edema also affect the contralateral lung.

Grade 3 placentation: incidence and neonatal outcome.

Although ultrasonically detectable placental changes have been correlated with fetal maturity, the relative incidence of each placental grade at various gestational ages has not been known. During a one-year study period, placental grading was evaluated in 1709 scans performed at 27 weeks' gestation or after. At 40 weeks' gestation or beyond, only about 20% of placentas had extensive calcification (Grannum grade 3). Significant placental calcification was rarely seen before 37 weeks' gestation. Placental grading could not be used to predict postmaturity. The incidence of fetal distress in labor was found to be increased with postmaturity as well as with other pregnancy complications that give rise to premature placental senescence, rather than with grade 3 placentas per se.

Preliminary clinical results with low flip angle spin-echo MR imaging of the head and neck.

A new approach for producing primarily T2- and proton-density-weighted MR images in less time than the conventional long TR, long TE imaging is to reduce the TR of a double spin-echo pulse sequence and to also reduce the RF excitation flip angle to minimize the resulting T1 sensitivity. In preliminary studies with a human volunteer and five patients with various diseases of the head and neck, conventional long TR, long TE and short TR, short TE images were compared with short TR, long TE images with reduced flip angles (45 degrees, 30 degrees), which required only 40% of the imaging time of the long TR images. The latter images showed a similar contrast pattern to the conventional T2-weighted image, and contrast-to-noise measurements indicated an increase in contrast between the lesion and nearby tissue when the flip angle was reduced. Furthermore, the maximum contrast/noise per unit imaging time on the short TR, long TE image was comparable to that on the long TR, long TE image. Optimization of the flip angle with short TR allows a substantial reduction in imaging time but with a reduction in multislice capability. This technique will be most useful in areas of complex anatomy where two or more orthogonal imaging planes are required, such as the head and neck.

Optimal photon energies with respect to absorbed dose for visualization of soft tissue masses with adipose tissue.

The photon energies which maximize the signal to noise ratio per unit absorbed dose (optimal photon energies) have been calculated for detection of soft tissue masses within adipose tissue 3--15 cm thick. The detection task simulates mammography in women with fatty breasts. Ideal, plain film and calcium tungstate screen-film systems were considered in the analysis. Net photographic density is not incorporated into this model; therefore, the optimal photon energy with respect to the signal to noise ratio per unit absorbed dose may not be the same as the photon energy which results in maximum film density per unit absorbed dose. Therefore, the model has limited applicability to film or screen-film systems. However, it is directly applicable to digital systems where brightness and contrast can be adjusted.

Oral contrast is not necessary in the evaluation of blunt abdominal trauma by computed tomography.

The administration of oral contrast (OC) is widely recommended for computed tomography (CT) of the abdomen in patients with blunt trauma. The purpose of this study was to determine whether routine abdominal CT scans performed without OC were associated with diagnostic error in patients with blunt trauma. Four hundred ninety-two patients were identified from our Trauma Registry who had CT scans for the evaluation of blunt abdominal trauma between January 1988 and December 1991. Seventy-six percent (372) of the CT scans were interpreted as negative, and 24% (120) were considered positive. OC was used in 8 (1.6%) of 492 patients. Only 1 of 372 patients whose initial non-OC--enhanced scan was negative subsequently required surgery. There were 5 bowel injuries among the 42 patients who underwent an abdominal operation; in none would the use of OC have ensured the preoperative diagnosis. We found that the omission of OC did not represent a disadvantage to patients with blunt trauma undergoing a routine abdominal CT scan. Potential time delays and the hazards associated with the use of OC were minimized.

Brief communication: effects of diagnostic irradiation during pregnancy on head circumference at birth.

A historical cohort study was carried out to evaluate the effects in utero medical ionizing radiation on head circumference at birth. The nature of medical practice in Rochester, Minnesota, and the Mayo Clinic medical records linkage system enabled us to provide accurate estimates of medical radiation absorbed dose in 9,793 pregnancies of 2,980 women pregnant in Rochester between 1917 through 1973. Data were controlled for sex of the fetus, duration of pregnancy and congenital head abnormalities. It was found that medical ionizing radiation in the second and third trimesters of more than 300 mrad were related to significantly decreased head circumference. There was no significant effect of radiation exposure in the first trimester or periconceptional period. Medical ionizing radiation in the second and third trimesters of more than 300 mrad is related to a significant yet minimal, decreasing head circumference at birth. Maximum effects were seen during the midgestational and second trimester periods.

Herpes zoster and diabetes mellitus: an epidemiological investigation.

Five hundred and ninety Rochester, Minnesota, residents were initially diagnosed with herpes zoster in the period 1945-59. Fifteen had diabetes mellitus before the onset of herpes. The expected number was 15.7. The entire herpes zoster cohort was followed subsequently for nearly 9400 person-years and 33 new cases of diabetes mellitus developed while the expected number was 30.6. The clinical spectrum of herpes zoster in individuals with diabetes mellitus was not different from that of zoster patients from the general population. We conclude that herpes zoster is not a risk factor for diabetes mellitus and that diabetes mellitus is not a risk factor for herpes zoster.

Average fetal depth in utero: data for estimation of fetal absorbed radiation dose.

To estimate fetal absorbed dose from radiographic examinations, the depth from the anterior maternal surface to the midline of the fetal skull and abdomen was measured by ultrasound in 97 pregnant women. The relationships between fetal depth, fetal presentation, and maternal parameters of height, weight, anteroposterior (AP) thickness, gestational age, placental location, and bladder volume were analyzed. Maternal AP thickness (MAP) can be estimated from gestational age, maternal height, and maternal weight. Fetal midskull and abdominal depths were nearly equal. Fetal depth normalized to MAP was independent or nearly independent of maternal parameters and fetal presentation. These data enable a reasonable estimation of absorbed dose to fetal brain, abdomen, and whole body.

Implantation metastasis of primary malignant rhabdoid tumor of the brain in an adult (one case report).

Primary malignant rhabdoid tumor (PMRT) of the brain is a rare and recently described neoplasm of youth. We report magnetic resonance imaging (MRI), computed tomography (CT), and pathology of one case of PMRT in an adult which seeded along the needle track for stereotactic biopsy.

Estimation and minimization of fetal absorbed dose: data from common radiographic examinations.

A simple method of estimating fetal absorbed dose from common abdominal and pelvic radiographic examinations is presented. The method uses experimentally determined normalized depth dose curves (rad/Roentgen exposure free-in-air) and sonographic localization of the fetus. The method is useful for estimating fetal absorbed dose when a pregnant woman inadvertently undergoes a radiographic examination. However, its primary value is in minimizing fetal dose when a woman, known to be pregnant, must undergo a radiographic examination. Selection of proper projection and deliberate adjustment of bladder volume can result in significant fetal dose reduction particularly in the critical first trimester.

Normalized organ doses for various diagnostic radiologic procedures.

Organ-absorbed doses for 24 diagnostic examination projections were measured using an Alderson Rando phantom. The organs of interest were testes, ovaries, thyroid, eyes, uterus, and active bone marrow. The reported values were normalized to the unit entrance exposure of each examination. Subsequent comparison of these measured values with the experimental and calculated values of other investigators showed reasonable agreement.

The relationship of placental grade by ultrasound to markers of fetal lung maturity.

Seventy-two amniocenteses with concurrent placental grading by ultrasound were performed during 66 pregnancies. No relationship was observed between placental grade and the mean ratio of lecithin to sphingomyelin (L/S) or the phosphatidylglycerol concentration. Both placental grade and fetal lung maturity were interrelated by the independent variable of gestational age. The latter may explain the trend observed between a mature L/S ratio and the placental grade. Grade 3 placentas were present in only 20% of patients studied at 37 weeks of gestation or later (12 of 61 patients), and in every instance a Grade 3 placenta was associated with an absence of neonatal respiratory distress.

Risk of cancer after herpes zoster: a population-based study.

Herpes zoster has been associated with immune suppression, as has an increased risk of cancer. To determine whether patients with herpes zoster are at increased risk for subsequent cancer, we followed 590 residents of Rochester, Minnesota, for 9389 person-years after the diagnosis of herpes zoster. Subsequent relative cancer risks, overall and by specific site, were determined for the entire cohort and selected subgroups. In addition, relative risks of cancer during various intervals after the diagnosis of herpes zoster were determined. The overall relative risk was 1.1 (95 per cent confidence interval, 0.9 to 1.3). Relative risks of specific cancer sites were not different from unity except for those for colon and bladder tumors in women, both of which were slightly elevated. Patients with disseminated, recurrent, or gangrenous zoster, with postherpetic neuralgia, and with ophthalmic zoster wee not at elevated risk for subsequent cancer. These findings do not support the investigation of patients for occult cancer at the time of diagnosis of herpes zoster or enhanced surveillance for cancer after such a diagnosis.