Biomedical subjects

R M Patten

Publications and source records attributed to R M Patten.

At least 37 records · Page 2Linked to original sources

PubMed1992

Nondisplaced fractures of the greater tuberosity of the humerus: sonographic detection.

In this retrospective study, the sonographic appearance of fracture of the greater tuberosity of the humerus was evaluated in 17 men and 14 women aged 20-69 years with acute, semiacute, or remote shoulder trauma in whom results of rotator cuff sonography had suggested the diagnosis of such a fracture. Clinical data, radiologic reports, sonograms, and initial plain radiographs of the shoulder were analyzed; clinical follow-up information was assessed in 22 patients. Sonography showed discontinuity and irregularity of the humeral cortex in all patients. In 25 patients (81%), displaced fracture fragments could be seen. Sonographic findings were suggestive of, but not specific for, fracture. Cortical abnormalities of the humerus were identified without modification of standard scanning protocols. A humeral fracture was confirmed with radiography in 24 patients; in 10 of them, the fracture had been missed initially on plain radiographs. It is concluded that, in evaluation of soft tissues in shoulder trauma, sonography may define rotator cuff abnormalities and occasionally help in detection of occult humeral fractures.

Adult↗

PubMed1991

Muscle spindle ultrastructure revealed by conventional and high-resolution scanning electron microscopy.

Muscle spindles in the tenuissimus muscle of mature golden Syrian hamsters were examined by conventional and high-resolution scanning electron microscopy (HRSEM). For conventional SEM, entire muscles were first fixed in 2.5% buffered glutaraldehyde. Spindles were then isolated with a dissecting microscope under darkfield illumination and postfixed in 1.0% OsO4. Some spindles were treated with 8 N HCl at 60 degrees C to clearly expose intrafusal fiber surfaces once the outer capsular sheath was mechanically disrupted. Preparation for HRSEM included aldehyde/osmium fixation and freeze-cleavage in liquid N2. The cytosol and certain cellular elements were also selectively extracted by immersion in 0.1% OsO4 for varying time intervals. In these preparations, the capsular sleeve showed a multilayered pattern of vesicle-laden cells with variant surface topography in different regions, including filopodia and small bristle-like surface-projections. An interlacing three-dimensional network of collagen fibrils intervened between the capsular lamellae. Within the spindles, sensory and fusimotor nerve endings closely adhered to the outer surfaces of intrafusal fibers. Sensory nerve terminals were enveloped by a prominent external lamina, and those that were cleaved open contained a plethora of elongated mitochondria that ran parallel with the longitudinal axis, along with vesicles, axoplasmic filaments, and lysosomes. Multiple adhesion sites between the sensory nerve membrane and the underlying sarcolemma of the intrafusal fiber were also observed in select regions. Fusimotor nerve endings were covered externally by processes of Schwann cells and their axoplasm was filled with a multitude of cellular organelles and synaptic vesicles.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Improved fat suppression in STIR MR imaging: selecting inversion time through spectral display.

By observing the fat-signal peak on the spectral display of a magnetic resonance (MR) imager while varying inversion time (TI), the authors determined the TI that produced the lowest fat peak for the best suppression of fat signal in subsequent short-TI inversion-recovery (STIR) MR imaging. In 25 volunteers who underwent imaging at multiple TIs, the TI that produced the lowest measured fat signal intensity was the same as that selected by means of TI tuning in 60% of cases and was within 5 msec in the remaining 40%.

Adipose Tissue↗

PubMed1991

Comparison of STIR and spin-echo MR imaging at 1.5 T in 45 suspected extremity tumors: lesion conspicuity and extent.

Short inversion time inversion recovery (STIR) imaging and a double-echo spin-echo (SE) sequence at 1.5 T in 45 sequential patients with suspected extremity tumors were compared to assess the number of lesions detected, subjective conspicuity of lesions, approximate volume of abnormality detected in each lesion, and identification of peritumoral brightening in tissues adjacent to each lesion. STIR sequences enabled detection of all 45 lesions; 44 were detected with the SE sequence. Tumor appeared most conspicuous on STIR images in 35 patients (78%) and was most conspicuous on SE images in 10 patients (22%). Peritumoral brightening, which indicated either peritumoral edema or microscopic tumor infiltration, was detected in 20 patients but was detected only with STIR sequences in nine patients. It is concluded that, although STIR and SE sequences are comparable for lesion detection in the extremities, most lesions appear more conspicuous with STIR. STIR may enable detection of a greater volume of abnormality than SE sequences and may therefore have important implications for local staging and surgical and radiation therapy planning.

Adolescent↗

PubMed1991

Root of the superior mesenteric artery in pancreatitis and pancreatic carcinoma: evaluation with CT.

To determine if changes involving the root of the superior mesenteric artery are specific for neoplasm, the authors retrospectively reviewed 173 computed tomographic (CT) examinations of patients with proved pancreatitis (103 examinations) and pancreatic ductal adenocarcinoma (70 examinations). Streaky infiltration of the fat surrounding the root was seen in 27 of 56 examinations of acute pancreatitis, in four of 24 examinations of chronic pancreatitis, in 12 of 23 examinations of pancreatitis complicated by abscess, and in 25 of 70 examinations of pancreatic carcinoma. Periarterial lymph nodes were visible in 14 with acute pancreatitis, in three with chronic pancreatitis, in six with pancreatic abscess, and in 11 with pancreatic carcinoma. A focal mass extended to within 1 cm of the root in 10 with acute pancreatitis, in two with chronic pancreatitis, in four with pancreatic abscess, and in 24 with pancreatic carcinoma; the mass obliterated the periarterial fat in seven with acute pancreatitis, in one with pancreatic abscess, and in 18 with pancreatic carcinoma. Circumferential encasement occurred in one with chronic pancreatitis, in four with pancreatic abscess, in 14 with pancreatic carcinoma, and in none with acute pancreatitis; nearly all cases of encasement revealed loss of periarterial fat. Thus, these indicators are not specific for neoplasm.

Abscess↗

PubMed1991

Unilateral hydrocephalus: prenatal sonographic diagnosis.

We studied six cases of unilateral hydrocephalus detected prenatally to analyze the sonographic features of the abnormality and to determine the cause and clinical outcome. In all cases, third-trimester sonograms showed marked unilateral lateral ventriculomegaly (mean atrial width, 4.4 cm) and normal contralateral lateral, third, and fourth ventricles. Five of the six cases had marked thinning of the cortical mantle on the affected side and shift of midline structures to the contralateral side. The causes of unilateral hydrocephalus were agenesis or stenosis of the foramen of Monro in three cases, transient obstruction of the foramen in one fetus with an intraventricular hematoma, underlying brain dysplasia in one fetus with a variant of holoprosencephaly, and undetermined in one case. All six neonates had placement of a ventriculoperitoneal shunt catheter; four of these have had normal cognitive development at follow-up. The remaining two infants have moderate to severe developmental impairment. Unilateral hydrocephalus is a rare anomaly that can be recognized by prenatal sonography. Even though unilateral ventriculomegaly may be marked, early diagnosis and treatment may result in a favorable clinical outcome.

Adult↗

PubMed1991

Ligamentous compression of the celiac axis: CT findings in five patients.

Compression of the celiac trunk by the median arcuate ligament of the diaphragm is an uncommon angiographic and surgical finding that rarely may be symptomatic. We retrospectively reviewed contrast-enhanced abdominal CT scans in five patients with severe ligamentous compression of the celiac axis, confirmed by surgery and/or angiography, and compared the findings with those of enhanced scans of 100 consecutive patients without known ligamentous compression. In all five patients with ligamentous celiac artery compression, CT showed effacement or narrowing of the celiac trunk by an anterior soft-tissue band. Dilated peripancreatic collateral vessels were seen in four cases, and poststenotic dilatation of the distal celiac trunk was seen in two cases. The normal appearance of the vasculature was seen in the majority (76%) of the 100 control subjects, but in eight patients the celiac origin was obscured on CT scans, and in 16 patients the celiac trunk appeared narrow or effaced. Our experience suggests that severe ligamentous celiac artery compression can be identified on CT. However, the isolated CT finding of effacement or obscuration of the celiac axis occurs sufficiently often in normal patients that it is not adequate evidence to establish the diagnosis of celiac artery compression.

Aged↗

PubMed1990

Metastases from malignant melanoma to the axial skeleton: a CT study of frequency and appearance.

Radiologic detection of bone lesions from malignant melanoma is reported to be uncommon or infrequent. To ascertain the characteristics and frequency of detection of melanoma metastases to the axial skeleton by CT, we retrospectively reviewed 464 body CT studies of 125 consecutive melanoma patients for presence, appearance, and site of skeletal metastases. Results were correlated with patient's age, sex, clinical course, and both the Clark and Breslow classifications of the primary lesion. Of 98 patients with metastatic disease evident on their CT studies, 17 (17%) had bony metastases; two (12%) of these 17 patients had skeletal lesions as the only CT evidence of metastatic disease. Metastatic bony lesions were predominantly osteolytic, slightly expansile, and commonly located in the spine. Associated soft-tissue masses were frequent, but periosteal reaction and identifiable tumor matrix were not seen. Skeletal metastases were found only in those patients with thick or intermediate primary melanoma (Breslow) classified as Clark level III or greater, and the CT demonstration of osseous metastases was a poor prognostic sign. The data suggest that CT detection of skeletal melanoma metastases is not uncommon. When CT is performed to evaluate for metastatic melanoma, the axial skeleton should be carefully examined, especially in those patients with more advanced primary lesions.

Adult↗

PubMed1990

Pelvic inflammatory disease. Endovaginal sonography with laparoscopic correlation.

We correlated endo-vaginal ultrasound (EVUS) results with laparoscopic findings in 16 patients with operatively confirmed acute pelvic inflammatory disease to evaluate the sensitivity and accuracy of EVUS for identification of uterine and adnexal pathology. Laparoscopy confirmed prospective sonographic abnormalities in 25 of 27 inflamed fallopian tubes (sensitivity, 93%) and in 19 of 21 ovaries with peri-ovarian inflammation (sensitivity, 90%). Overall accuracy for EVUS prediction of peri-ovarian or tubal disease was 91% and 93%, respectively. However, EVUS was less sensitive to uterine abnormalities and detected inflammatory changes in only three of 12 confirmed cases (25%). EVUS also failed to demonstrate small quantities of purulent fluid (less than 20 cc) in the pelvic cul-de-sac in six of nine cases.

Acute Disease↗

PubMed1990

The fetal genitourinary tract.

Early recognition of fetal urinary tract anomalies may dramatically influence obstetric or neonatal management. Major fetal urinary abnormalities, including renal agenesis, obstructive lesions, and cystic disease, may be clinically silent but readily identified by sonography. Careful evaluation of the fetal genitourinary tract should therefore be an important component of the routine screening obstetric sonogram. Appreciation of normal sonographic appearances of the fetal genitourinary tract may facilitate early recognition of the abnormal fetus. Accurate prenatal sonographic characterization of a renal abnormality and evaluation of renal function are essential for fetal prognosis and management.

Constriction, Pathologic↗

PubMed1989

Disparity of amniotic fluid volume and fetal size: problem of the stuck twin--US studies.

The "stuck twin" phenomenon in monochorionic diamniotic (MCDA) pregnancies is characterized by marked disparity in both fluid volume and fetal size between the twin gestations. To determine the prevalence, sonographic characteristics, and clinical outcome of this phenomenon, discharge summaries, placental pathologic reports, and prenatal sonograms from 307 twin pregnancies were reviewed. Of 52 cases of MCDA pregnancies, 18 (35%) demonstrated marked disparity in amniotic fluid volume. In 16 of these 18 cases there was discordant twin growth, further suggesting the diagnosis of twin transfusion syndrome. All 16 cases and an additional nine cases supplied by another center demonstrated a small, morphologically normal fetus in an oligohydramniotic sac suspended anteriorly (72%) or laterally (28%) in the uterus. The amniotic membrane separating this twin from the larger twin in the polyhydramniotic sac was thin, closely applied to the smaller fetus, and difficult to detect. Perinatal morbidity was 100% for all twin pairs, and premature labor occurred in all cases. Perinatal mortality ranged from 88% for the larger/poly twin to 96% for the small/oligo twin.

Adult↗

PubMed1989

Twin embolization syndrome: prenatal sonographic detection and significance.

Twin embolization syndrome (TES) is a complication of monozygotic twinning following in utero demise of the co-twin. Passage of thromboplastic material into the circulation of the surviving twin results in ischemic structural defects of the central nervous system, gastrointestinal tract, and genitourinary system. In six cases of this rare abnormality, sonographically normal fetuses subsequently demonstrated ventriculomegaly, porencephaly, cerebral atrophy, or microcephaly following demise of the co-twin. Extracranial abnormalities included small bowel atresia (two cases) and renal cortical necrosis (one case). Surviving twins all had neurodevelopmental delay at follow-up. Two fetuses were aborted because of sonographically apparent, progressively severe brain abnormality. The lone survivor of a dizygotic triplet gestation was normal, despite sonographic findings of TES in the co-triplets. Because of poor outcome, prenatal sonographic diagnosis of TES may influence antenatal or neonatal management of the surviving monozygous twin. Recognition of TES may permit accurate postnatal counseling of prognosis and recurrence risks.

Adult↗

PubMed1989

Subcutaneous metastases from malignant melanoma: prevalence and findings on CT.

We reviewed 197 body CT studies on 53 sequential patients who had a histologic diagnosis of malignant melanoma in order to determine the CT appearance, pattern of spread, and prevalence of subcutaneous melanoma metastases. Seventeen (38%) of 45 patients with CT evidence of metastatic melanoma had subcutaneous nodules shown on CT. Five patients (11%) had subcutaneous nodules as the only indication of metastatic disease on their CT scans. All patients who developed subcutaneous metastases had primary lesions classified as Clark level IV or V. (The Clark classification is based on the depth of tumor invasion and is rated I to V.) Metastases appeared as small, discrete rounded densities in the subcutaneous fat; lesions were occasionally subtle because of their small size and peripheral location. The location of subcutaneous nodules could not be predicted consistently on the basis of the site of the primary malignancy. We conclude that subcutaneous metastases are common with melanoma in patients with Clark level IV or V lesions. These subcutaneous nodules are readily detected on CT scans if the subcutaneous tissues are carefully examined. The detection of these lesions may affect management or prognosis of patients, especially in those cases where subcutaneous nodules are the only CT evidence of metastatic disease.

Adipose Tissue↗

PubMed1987

Limb-body wall complex: II. Limb and spine defects.

Limb defects from 25 fetuses with limb-body wall (LBW) complex were evaluated to determine the mechanism of limb damage. The limb defects could be divided into 3 pathogenetic groups: (1) secondary to disruption of embryonic vessels and surrounding tissue (84%), (2) secondary to amniotic bands or adhesions (16%), and (3) deformation versus hemorrhage (44% with club feet), with some fetuses having more than one pathogenetic mechanism causing limb defects. The hypothesis that the majority of limb defects resulted from disruption of embryonic vessels was supported by the following findings: 96% of the LBW complex fetuses had limb defects; the lower limbs were at greater risk of damage than the upper limbs (28% rt arm, 52% lt arm, 60% rt leg, 72% lt leg); there was a distal to proximal progression of limb damage in 92% of the fetuses; statistical analysis of comparing the location of the most severe limb defect and the body wall defect did not find concordance between the side (p = 1.0) and the region (p = 0.18) of the body wall defect; and limb defects found in the human specimens were similar to those produced in experimental animals following disruption of embryonic vessels at a corresponding gestation. In the specimens with amniotic band related limb defects (16%), the most likely pathogenesis is mechanical rupture through the amnion in the presence of a persistent extraembryonic coelom or from adhesion of the amnion to necrotic embryonic tissue after the initial disruptive event. Club feet were present in 44% and may be due either to disruption of embryonic vessels or to deformation. Further studies are needed to resolve this question.

Abdominal Muscles↗

PubMed1987

Distinguishing normal from abnormal gestational sac growth in early pregnancy.

In order to evaluate normal and abnormal gestational sac development, serial sonograms were performed in 83 women whose initial sonogram demonstrated a gestational sac lacking a detectable embryo. Of 53 normal gestations, the mean sac growth was 1.13 mm/day (range, 0.71-1.75). In comparison, of 30 abnormal gestations, 24 demonstrated sac growth, and of these, the mean growth was 0.70 mm/day (range, 0.14-1.71). Based on these observations, we suggest that gestational sac growth of less than or equal to 0.6 mm/day is evidence for abnormal development. Analysis of the initial and follow-up scans for the 53 normal gestations showed that a living embryo was always detected when the mean gestational sac was greater than 25 mm in average diameter, and a yolk sac was always seen when the mean sac diameter was greater than 20 mm. In comparison, of 30 abnormal gestations, six were greater than 25 mm without a detectable embryo, and four were greater than 20 mm without a yolk sac. Recommendations for the optimal time of a follow-up sonogram are presented based on the initial sac size.

Embryo Loss↗

PubMed1987

Fetal bowel. Normal sonographic findings.

The normal sonographic appearance of fetal colon and small bowel is reported in a prospective study of 130 fetuses. The colon, which appeared as a continuous tubular structure located around the perimeter of the abdominal cavity, was seen in some fetuses as early as 22 menstrual weeks and in all fetuses examined after 28 weeks. Colon diameter demonstrated a linear relation (r = 0.82) with menstrual age, reaching a maximum of 18 mm at term. In comparison, small bowel was located centrally and individual segments never exceeded 7 mm in diameter or 15 mm in length. Small bowel loops were seen in only 30% of fetuses examined after 34 weeks. Peristalsis was routinely demonstrated of the small bowel, but was not observed in the colon.

Colon↗

PubMed1986

Bowel migration in the normal fetus: US detection.

Ten fetuses underwent ultrasound scanning at 7-10 weeks gestational (postmenstrual) age. In all cases, an echogenic mass measuring 0.5-1.0 cm was demonstrated within the base of the umbilical cord at its insertion into the fetal abdomen. No area with echogenicity characteristic of the small bowel was identified within the lower part of the fetal abdomen. All fetuses were reexamined 4-12 weeks later, at which time the mass in the umbilical cord was no longer seen, and normal fetal bowel was visualized in the lower abdominal cavity of the fetus. This sequence of findings appears to represent the sonographic demonstration of normal fetal bowel migration early in gestation and should not be confused with defects of the abdominal wall such as omphalocele or gastroschisis.

Abdominal Muscles↗

PubMed1986

Limb-body wall complex: in utero sonographic diagnosis of a complicated fetal malformation.

Limb-Body Wall Complex is a complicated fetal malformation with the essential features of neural-tube defects, body-wall disruption, and limb abnormalities. This complex should be distinguished from other body-wall defects including omphalocele and gastroschisis since the prognosis for limb-body wall complex is uniformly poor. For 13 cases of this unusual fetal anomaly, sonographic, radiologic, and pathologic findings were correlated. Thoracic or abdominal body-wall defects, neural-tube abnormalities, severe scoliosis, positional deformities, and abnormalities of fetal membranes were consistently demonstrated on in utero sonograms. Results show that the diagnosis of limb-body wall complex can be made by prenatal sonography.

Abdominal Muscles↗