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Biomedical subjects

D S Gierada

Publications and source records attributed to D S Gierada.

27 records · Page 2Linked to original sources
PubMed1997

Pseudomass due to atelectasis in patients with severe bullous emphysema.

OBJECTIVE: This study describes the atypical presentation of atelectasis as a pseudomass in patients with severe bullous emphysema. MATERIALS AND METHODS: The radiologic studies and clinical records of 11 patients with severe bullous emphysema and mass-like opacities representing atelectatic lung were reviewed. The diagnosis was proven by surgery in nine patients and by follow-up imaging in two patients. RESULTS: Pseudomasses were found primarily in the upper lobes and the right middle lobe (n = 10). Common features included an oblong, lenticular, or triangular shape (n = 8); a sharp interface with aerated lung (n = 9); hyperexpansion of the hemithorax containing the pseudomass (n = 8); a central location abutting the mediastinum (n = 8); and adjacent emphysema (n = 11). CT revealed subsegmental atelectasis in other lobes adjacent to the bullous lung in six patients. In three patients, the pseudomasses were associated with persistent distention of large bullae following spontaneous pneumothoraces. Reexpansion of pseudomasses occurred in seven of the eight patients who underwent resection of bullous lung. CONCLUSION: These pseudomasses most likely result from compression of the lung by adjacent large bullae. The diagnosis should be suspected when central, sharply marginated, mass-like opacities that are oblong, lenticular, or triangular are bordered by severe bullous emphysema.

Diagnosis, Differential↗
PubMed1996

Radiology of pulmonary emphysema and lung volume reduction surgery.

Lung volume reduction surgery (LVRS), which involves the bilateral wedge resection of 20% to 30% of the most diseased lung through a median sternotomy, is emerging as a promising treatment option for select patients with severe, debilitating emphysema. This article details our observations and preliminary investigations related to the imaging evaluation of patients including selection criteria, postoperative findings, and structural changes in the thorax after surgery. Routine preoperative evaluation includes inspiratory and expiratory chest radiographs, computed tomography (CT) examination, and nuclear medicine lung scan. Investigational studies include quantitative CT to assess disease severity and dynamic magnetic resonance imaging to study respiratory movements. Postoperative improvement in FEV1, oxygenation, and exercise tolerance correlate with the degree of heterogeneity, hyperinflation, lung compression, upper lobe severity, and percentage of retained mildly diseased lung shown on preoperative imaging studies. Postoperative radiographic monitoring is important for detection of complications. Postoperative follow-up examinations show reduced thoracic distention, improved coordination of respiratory movement, and increased diaphragm curvature and excursion, supporting the hypothesis of improved respiratory mechanics as a major contributing factor to the success of LVRS.

Follow-Up Studies↗
PubMed1995

Diaphragmatic motion: fast gradient-recalled-echo MR imaging in healthy subjects.

PURPOSE: To investigate the feasibility of imaging diaphragmatic motion with a fast gradient-recalled-echo (GRE) magnetic resonance (MR) pulse sequence. MATERIALS AND METHODS: Fast GRE pulse sequences in sagittal and coronal planes were used to acquire repeated, single-level, 1.2-second scans in 10 healthy volunteers during deliberately slowed, approximate-vital-capacity breathing. Motion was analyzed subjectively by viewing the image sequences as cine loops and quantitatively by measuring the displacement of different points on the diaphragm at a workstation. RESULTS: Temporal and spatial resolutions were adequate in all subjects. Absolute excursion of the domes was 4.4 cm on the right and 4.2 cm on the left. Analysis of diaphragmatic displacement at different locations revealed a gradient of excursion that increased from anterior to middle to posterior (P < .05-.001; paired t test). Excursion of the lateral aspects was greater than that of the medial aspect (P < .001). CONCLUSION: Fast GRE MR imaging can be reliably used to demonstrate diaphragmatic motion and may prove useful in the investigation of normal and abnormal respiratory mechanics.

Adult↗
PubMed1993

MR imaging of the sacral plexus: normal findings.

Imaging of the sacral plexus requires evaluation of both intradural and extradural components with cross-sectional techniques. Although CT is useful, individual extradural sacral nerves and the sacral plexus usually cannot be distinguished from adjacent structures. The higher contrast resolution provided by MR imaging allows the region of the sacral plexus to be examined in greater detail. With MR imaging, the constant relationship of the neural components to one another, and the gluteal vessels in their course from the sacrum to the greater sciatic foramen, can be shown consistently. An understanding of the anatomy of this area in multiple planes can aid in more accurate localization of abnormalities involving the sacral plexus. This pictorial essay reviews the MR appearance of the region of the sacral plexus.

Cadaver↗
PubMed1993

MR imaging of the sacral plexus: abnormal findings.

Patients with symptoms of sacral plexopathy, radiculopathy, or sciatica may have disease originating in the neural elements, sacrum, bony pelvis, pelvic soft tissues, or gluteal region. As illustrated in our companion article, the sacral plexus and surrounding structures can be visualized in detail with MR imaging. This pictorial essay illustrates the MR findings in a number of abnormalities affecting the sacral plexus. Multiplanar MR examination is particularly helpful in defining neural levels of involvement by disease in this region.

Abscess↗
PubMed1988

The influence of potassium and bicarbonate on red blood cell sodium in the DOCA-hypertensive pig.

The effects of plasma potassium, and blood bicarbonate on red blood cell sodium were studied in vivo in seven pigs implanted subcutaneously with DOCA (100 mg/kg) impregnated in Silastic. Mean arterial pressure, red blood cell sodium, plasma sodium, plasma potassium, and blood bicarbonate were measured from 5 days pre-implant to 30 days post-implant. One day post-implant, the pigs had significant increases in mean arterial pressure and red cell sodium content, and a significant decrease in plasma potassium concentration. In KCl infusion studies when plasma potassium was raised an average of 2.13 +/- 0.17 mEq/L, red blood cell sodium fell 0.61 +/- 0.10 mEq/L cells. When blood bicarbonate was raised 6.9 mEq/L by infusing NaHCO3, red blood cell sodium increased 0.79 mEq/L cells. The changes in red blood cell sodium were rapid, occurring within one hour after either of these plasma electrolyte shifts. We conclude that either plasma potassium or blood bicarbonate, or both, can serve as regulators of red blood cell sodium content in vivo, and cause the elevated level of red blood cell sodium that we have found in the DOCA-hypertensive pig. If these plasma electrolyte changes cause a similar increase in intracellular sodium in vascular smooth muscle or in a blood pressure regulating center in the brain, they may play a role in producing the arterial pressure elevation of mineralocorticoid-induced hypertension.

Animals↗