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Biomedical subjects

S S Kramer

Publications and source records attributed to S S Kramer.

At least 37 records · Page 2Linked to original sources
PubMed1995

Physiologic imaging of the lung with volumetric high-resolution CT.

The combination of high-resolution computed tomography (HRCT), rapid volumetric scanning, and advanced image display and analysis applications software is a powerful potential tool for the evaluation of physiologic and pharmacologic events in the lung. Currently employed in the experimental setting, this tool can provide verifiable and quantifiable information about regional responses in the lung, which were previously impossible to demonstrate. This is particularly true when physiologic or pharmacologic effects result in an anatomic change that can be directly imaged and measured within the limits of CT resolution. However, information about events occurring beyond resolution limits is potentially available indirectly from lung density and pulmonary blood flow measurements using CT techniques. The results of animal airway reactivity experiments making use of i.v. methacholine and CT imaging tools are presented as an example of "physiologic imaging."

Animals↗
PubMed1993

The evaluation of pediatric feeding abnormalities.

An appreciation of normal age-related feeding behavior is a prerequisite for the study of pediatric feeding disorders. When faced with a child with dysphagia, the diagnostic evaluation including history, physical and developmental exam, and feeding observation, followed by appropriate diagnostic tests forms the basis for understanding the underlying pathophysiology and the anticipated developmental progression. It makes possible the formulation and implementation of an optimal treatment strategy, which can be monitored for results and modified when needed. Four case examples are provided.

Child↗
PubMed1993

Pulmonary tuberculosis in children.

TB is no longer the scourge it once was, but it remains an important cause of morbidity and mortality worldwide. Fueled by increasing poverty, homelessness, immigration, drug abuse, declining prevention programs, and the HIV epidemic, its incidence in the United States has increased dramatically. The complex natural history of pulmonary TB in children is reflected in its varied radiographic manifestations. Strict distinction between "adult" and "childhood" patterns of TB should be avoided (Fig 16). In general, adenopathy is the footprint of childhood primary pulmonary TB, with or without a readily apparent primary parenchymal focus or pleural effusion. Infants and young children are more likely to present with adenopathy only than their older counterparts. The pediatric tracheobronchial tree is particularly susceptible to compression by surrounding nodes, producing segmental atelectasis, or less commonly, obstructive emphysema. Self-limited lymphohematogenous dissemination is the rule, but actual miliary disease is the exception. Pediatric postprimary TB, when it occurs, is usually observed in adolescents. It is characterized by parenchymal disease with an anatomic bias for the upper lung zones. Proper image interpretation is inextricably dependent on an understanding of the pathogenesis of this fascinating and often baffling illness whose appearance widely varies depending on host age and immunity as well as the virulence of the organism itself.

Adolescent↗
PubMed1993

Assessment of methacholine-induced airway constriction by ultrafast high-resolution computed tomography.

Assessment of changes in airway dimensions during bronchoconstriction is conventionally based on measurements of respiratory mechanics. We evaluated the efficacy of ultrafast high-resolution computed tomography (UHRCT) to directly determine the dynamic changes in cross-sectional area (CSA) of airways in response to methacholine (MCh). UHRCT scans were obtained at functional residual capacity before (baseline) and after intravenous bolus injections of MCh (10(-8.5)-10(-7.0) mol/kg) to seven mechanically ventilated pigs. Changes in CSA of bronchi of varying baseline size (1-10 mm diam) were determined by using a customized image processing software package (VIDA) based on a user-directed computer-adjusted edge-finding algorithm. MCh induced dose-dependent decreases in CSA, which were paralleled by increases in airway opening pressure at higher doses of MCh; at lower doses of MCh, decreases in CSA of smaller airways were detected without concomitant changes in airway opening pressure. Changes in CSA were heterogeneous and variable, especially in the smaller airway ranges. The results of the present study support the concept that UHRCT can be used in conjunction with bolus challenges to effectively determine dose-response changes in airway caliber in both large and small airways. This technique provides data that may not be reflected by conventional lung function measurements and, hence, is a useful tool to study airway reactivity.

Animals↗
PubMed1989

CT of severe renal trauma in children: evaluation and course of healing with conservative therapy.

Over a 2-year period, blunt renal injuries were classified on a four-point scale: grade 1, contusions; grade 2, tears limited to the cortex (renal lacerations); grade 3, tears extending to the collecting system (renal fractures); and grade 4, renal vascular pedicle injuries. We report our findings in nine children with grade 2 and grade 3 blunt renal injuries who were evaluated with CT. One patient had a nephrectomy; the other eight were managed nonsurgically. Six patients had follow-up CT scans 5-19 months later to assess healing. Scars were evident in each case, and the extent of deformity paralleled the magnitude of the initial injury. One patient with a grade 2 injury and two patients with grade 3 injuries healed with small focal scars; three patients with grade 3 injuries healed with large polar scars. In five patients, the CT findings were compared with the findings on 99mTc-DTPA renal imaging. The injured kidneys contributed 30-45% (mean, 38%) of total renal function. In six patients with renal trauma who were treated conservatively, the involved kidneys healed and significant kidney function was preserved, although early surgical intervention might have been beneficial for one of these patients. Prospective studies are needed to evaluate further the effectiveness of this conservative approach.

Child↗
PubMed1988

Gastrointestinal inflammation after bone marrow transplantation: graft-versus-host disease or opportunistic infection?

Gastrointestinal inflammation after allogeneic bone marrow transplantation may be due to acute graft-versus-host disease (GVHD) and/or superinfection with opportunistic organisms. Twenty-eight patients with barium studies suggesting gastrointestinal inflammation after bone marrow transplantation and either acute GVHD, viral infection, or both were studied to characterize the radiographic appearances of each disease and to determine whether acute GVHD could be distinguished from viral superinfection on the basis of radiographic findings. Thirteen patients had minimal or no acute GVHD, with viral infection proved in eight and strongly suspected in four others; the remaining patient was thought to have nonspecific inflammatory bowel disease. Five patients had pure acute GVHD, and 10 patients had viral enteritis superimposed on acute GVHD. Radiographic abnormalities were found in the gastrointestinal tract in both acute GVHD and viral infection and were more extensive than previously reported. Findings were similar in both entities, although gastric abnormalities were not seen in pure acute GVHD but only in viral infection, either alone or together with acute GVHD. Prolonged small bowel barium coating occurred in both viral infection and acute GVHD. Fold thickening evolved into fold effacement with a shaggy contour in two patients with viral infection. Colonic findings in all groups mimicked ulcerative colitis. Our data indicate that differentiation between acute GVHD and viral enteritis is not possible on the basis of radiographic findings alone. Both entities should be considered when gastrointestinal inflammation occurs after bone marrow transplantation.

Adolescent↗
PubMed1987

Pneumatosis intestinalis in children after allogeneic bone marrow transplantation.

Four children, ages 3 to 8 years, developed pneumatosis intestinalis (PI) after allogeneic bone marrow transplantation (BMT) for acute leukemia or severe aplastic anemia. PI was detected at a median of 48 days (range, 10-63 days) after BMT and was associated with abdominal symptoms and clinical signs. All patients had severe systemic and/or high-grade cutaneous acute graft-versus-host disease (AGVHD) at some time after BMT and were receiving corticosteroids at the time of development of PI; however, PI was associated with concomitant severe AGVHD in only one patient. One patient with PI had Hafnia alvei bacteremia and another patient had gastroenteritis due to rotavirus and adenovirus. All patients were treated with supportive care and systemic broad-spectrum antibiotics, and PI resolved 2-16 days after onset. Two patients died with BMT-associated complications unrelated to PI. Multiple factors contribute to the development of PI after BMT, and the prognosis for recovery from PI is good with medical management alone. Overall survival in these patients is dependent on the frequency and severity of other conditions, such as AGVHD and opportunistic infections, after BMT.

Acute Disease↗
PubMed1987

Use of CT scans in selection of patients for pectus excavatum surgery: a preliminary report.

A pectus index can be derived from dividing the transverse diameter of the chest by the anterior-posterior diameter on a simple CT scan. In a preliminary report, all patients who required operative correction for pectus excavatum had a pectus index greater than 3.25 while matched normal controls were all less than 3.25. A simple CT scan may be a useful adjunct in objective evaluation of children and teenagers for surgery of pectus excavatum.

Adolescent↗
PubMed1986

Computed tomography of gastrointestinal inflammation after bone marrow transplantation.

Overwhelming secretory diarrhea can be a major complication after bone marrow transplantation, associated usually with acute graft-versus-host disease (AGVHD). Radiographic evaluation may be hampered by nausea, vomiting, or debilitation. Computed tomography (CT) in seven such patients demonstrated diffuse wall thickening in the small intestine, colon, and/or mesentery. In two cases, prolonged adherence of oral contrast material to the luminal surface resulted in bizarre patterns of coating. In two others, a layer of low attenuation within the thickened wall produced a target appearance consistent with submucosal edema or hemorrhage. Small bowel dilatation and fold enlargement was the only finding in one patient. The role that superinfection of the gastrointestinal tract with opportunistic organisms can play in this immunocompromised group of patients is less well established. In this group of patients, the findings were due to AGVHD in two, AGVHD and viral enteritis in two, and viral enteritis alone in three. CT may be an alternative to routine contrast studies in assessing the extent of gastrointestinal tract involvement after bone marrow transplantation. Neither contrast studies nor CT were able to differentiate between AGVHD and viral enteritis.

Adolescent↗
PubMed1985

Dynamic imaging of the pharynx.

The technique of dynamic imaging of the pharynx and some supplementary maneuvers which can be tailored to the individual patient's needs are discussed in detail. An approach to the analysis of normal and abnormal swallowing studies is presented.

Adult↗
PubMed1985

Pharyngoesophageal interrelationships: observations and working concepts.

Simultaneous disorders of the pharynx and esophagus are so frequent that the complete swallowing chain should be examined in all patients with dysphagia. Data are presented to support the concept that such simultaneous disorders represent related phenomena; the mechanism involves changes in cricopharyngeal function seen radiographically as cricopharyngeal prominence. If neurologic disease has been excluded, cricopharyngeal prominence may be the clue to esophageal disease. When cricopharyngeal prominence is found during dynamic imaging of the pharynx, intensive examination of the esophagus and a search for signs of compensation or decompensation in the pharynx should be undertaken.

Cineradiography↗
PubMed1985

Special swallowing problems in children.

As the swallowing process evolves from infantile suckle feeding through transitional feeding to mature function, the process can go awry at many points. Understanding the changes in structure and function of the mouth and pharynx that occur with growth and development is of basic importance. When a child is referred because of unsuccessful feeding or suspicion of aspiration, dynamic imaging of the swallowing mechanism and scrutiny of radiographic abnormalities described in this article can lead to greater understanding of the underlying cause and to more effective treatment.

Adult↗
PubMed1985

The Swallowing Center: concepts and procedures.

This paper describes the purpose and organization of a dedicated center at The Johns Hopkins Medical Institutions for the evaluation of swallowing problems. The multidisciplinary approach outlined will permit a better understanding and more accurate diagnosis of the functional or organic lesions affecting the swallowing mechanisms. Illustrative cases are presented.

Adult↗
PubMed1985

Life-threatening airway obstruction as a complication to the management of mediastinal masses in children.

Life-threatening airway obstruction from large mediastinal masses in children poses a difficult diagnostic and therapeutic dilemma, requiring the close coordination of a pediatric surgeon, anesthesiologist, radiologist, and oncologist. To focus on this problem, the anesthetic and surgical management of 50 consecutive children with mediastinal masses treated between 1978 and 1984 were reviewed. Thirty children presented with respiratory symptoms; nine had life-threatening respiratory compromise with dyspnea, orthopnea, and stridor. Thirteen of these symptomatic children had marked compression of the trachea and/or mainstem bronchi on radiographic studies. The tracheal cross-sectional area which was measured by computed tomography was decreased by 35% to 93% of the normal tracheal dimensions in these children. Nonresectable malignant neoplasms including lymphoma, Hodgkin's disease, rhabdomyosarcoma, and neuroblastoma were the eventual diagnoses in 10 of these patients. The other 3 patients were less than 4 years old and had benign lesions. General anesthesia was judged to be prohibitively risky in 5 of 13 patients. The diagnosis was established by node or needle biopsy under local anesthesia, and general anesthesia was deferred until the compromised airway was alleviated by radiation and chemotherapy. General anesthesia with endotracheal intubation was administered to 8 patients, 5 of whom developed total airway obstruction. Using a variety of maneuvers, ventilation was reestablished in all 5 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗