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Biomedical subjects

T H Berquist

Publications and source records attributed to T H Berquist.

At least 91 records · Page 5Linked to original sources
PubMed1985

Magnetic resonance imaging: application in musculoskeletal infection.

Forty-two patients with clinically suspected osteomyelitis were examined using magnetic resonance imaging (MRI). Twenty-seven patients (64%) had previous surgery or fracture, and 15 (36%) were referred for differentiation of acute osteomyelitis from bone tumors or other pathologic conditions. MRI was compared with computed tomography in 12 cases and with 111In-labeled leukocytes scans in 22. With MRI, 92% of proved infections were detected, and bone and soft-tissue changes were more evident than with routine radiographs, tomography, or computed tomography. In patients with negative cultures and no previous surgery or fracture, it was difficult for MRI to differentiate operative changes from infection. In these patients, 111In-labeled leukocyte images were more specific than MRI.

Adolescent↗
PubMed1985

Magnetic resonance imaging of soft-tissue tumors: comparison with computed tomography.

Twenty-seven patients with soft-tissue tumors were examined with a Picker 0.15-tesla resistive magnet and by computed tomography (CT). In all but one patient, MRI was better than or equal to CT in defining the anatomic extent of the tumor. We could determine whether major vascular structures were engulfed by the tumor in 80% of the MRI examinations but only in 62% of the CT scans. MRI and CT were equally effective in determining the presence or absence of bony invasion. The MRI images of all the tumors showed increased signal intensity relative to normal muscle when spin-echo (SE) pulse sequences with long repeat times were used (SE: echo time [TE], 60 ms; repetition time [TR], 2,000 ms). When T1 weighted pulse sequences were used (SE: TE, 30 ms; TR, 500 ms or inversion recovery: inversion time, 500 ms; TE, 40 ms; TR, 2,000 ms) the malignant tumors showed decreased signal intensity compared to normal muscle. Only lipomas showed high signal intensity on both T1 and T2 weighted pulse sequences.

Adolescent↗
PubMed1985

Magnetic resonance imaging in a routine clinical setting.

The results of magnetic resonance imaging (MRI) examinations in the first 1,000 consecutive patients who were studied by this technique at our institution were reviewed to determine the disease states encountered, the sensitivity and accuracy of results, and the value of the examination as compared with computed tomography and other imaging procedures. The MRI device was a 0.15-tesla resistive magnet that used a variety of saturation recovery, spin echo, and inversion recovery pulse sequences to produce images. MRI was found equal to or superior to other imaging techniques in most cases. Exceptions included organs or body regions that are prone to excessive respiratory or vascular motion, lesions that necessitate exquisite spatial resolution for diagnosis, and lesions in which angulation of the viewing plane is necessary for optimal depiction. Fresh blood and calcification within a lesion were also difficult to detect with use of MRI.

Adolescent↗
PubMed1985

Utility of the plain abdominal radiograph for diagnosing ureteral calculi.

Our study was designed to measure sensitivity, specificity, predictive value, and accuracy of the plain abdominal radiograph (PAR) for diagnosing ureteral calculi (UC) in our emergency department (ED), and to determine if obtaining this test in the ED provides clinically useful diagnostic information. Records of 206 adult patients (147 men, 59 women) who underwent emergency excretory urography as part of an ED evaluation for possible ureteral stones were reviewed. A retrospective scoring index was devised to estimate the clinical probability of a ureteral stone for each patient. All patients had a PAR shortly before the excretory urogram (EXU) was performed. Each PAR was separated from the corresponding EXU, and both were independently reviewed for radiographic evidence of ureterolithiasis. The results of the PAR and EXU interpretations were compared. There were 92 true-positive PARs (45%), 19 false positives (9%), and 39 true negatives (19%), yielding a sensitivity of 62% and a specificity of 67%. In patients with a high estimated clinical probability of a ureteral calculus, the PAR had a positive predictive value of 86% and a negative predictive value of 22%. In the remaining patients, the positive and negative predictive values of the PAR were 69% and 72%, respectively. Each patient's clinical index score was compared to his or her EXU results. For detecting UC, the sensitivity of our scoring index was 82%, and the specificity was 51%; the positive predictive value of the scoring index was 82%, and the negative predictive value was 52%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Bone tumors: magnetic resonance imaging versus computed tomography.

The magnetic resonance (MR) imaging characteristics of bone tumors are described and the clinical utility of MR imaging in patient evaluation is reported. Fifty-two patients with skeletal lesions were examined with a Picker MR imager (0.15-T resistive magnet). Twenty-five patients had primary malignancies, seven had benign bone neoplasms, 15 had skeletal metastases, and five had neoplasm simulators. Forty-five patients had CT scans available for comparison. For demonstrating the extent of tumor in marrow, MR was superior to CT in 33% of cases, about equal to CT in 64%, and inferior to CT in 2%. For delineating the extent of tumor in soft tissue, MR was superior to CT in 38% of cases and about equal to CT in 62%. CT was superior in all cases for demonstrating calcific deposits and pathologic fractures. In four patients with metal prostheses or surgical clips, MR was superior to CT in documenting recurrent tumor because of artifactual degradation of the CT image. Direct sagittal and coronal images from MR permit accurate assessment of the relationship of tumor to adjacent normal structures, including the physis, joints, and neurovascular structures. MR is useful in the evaluation of bone tumors: it is of greatest value in evaluations of the peripheral skeleton, the medullary canal, soft tissues, and postoperative tumor recurrence. With a 0.15-T magnet, MR is less useful in the evaluation of the axial skeleton and cortical bone.

Aged↗
PubMed1985

Magnetic resonance imaging of hemorrhage.

The magnetic resonance imaging (MRI) characteristics of evolving hemorrhage are discussed and compared with those of computed tomography (CT). Studies of 15 hematomas were undertaken in four mongrel dogs. The hematomas were created by the injection of autologous blood into the subcutaneous tissues of the thigh. The hematomas were studied serially with both MRI and CT. Pulse sequences included spin-echo (2100 msec TR, 40 and 80 msec TE) and inversion-recovery (2100 msec TR, 400 msec TI, 40 msec TE). Relaxation times (T1 and T2) were calculated in each case. CT values (H) were also obtained. In addition, 24 single and 14 serial scans of hemorrhage were obtained from 24 patients. MRI was performed on a 0.15-T resistive magnet scanner. T1 and T2 relaxation times and CT values decreased as the hematomas resolved. T1 and T2 relaxation times of intraparenchymal hemorrhage tended to remain elevated with time. MRI seems to be more sensitive than CT for the detection of hemorrhage, primarily because of superior contrast resolution.

Adolescent↗
PubMed1985

Evaluation of radiographic findings in painful hip arthroplasties.

A retrospective study of 50 surgically confirmed painful hip arthroplasties was performed to identify the roentgenographic findings that are most important in the detection of component loosening or infection. Plain film radiographs and subtraction arthrograms were reviewed in all cases, and specific features revealed by these two radiographic modalities indicative of component failure were identified. Seventeen patients had radioisotope bone scans and 13 of these had additional gallium scans. Plain film roentgenograms correctly identified loosening in 69% of acetabular and 84% of femoral components. Subtraction arthrography had an accuracy of 96% for both acetabular and femoral component loosening. Scintigraphic studies were correct in 77% of acetabular and 89% of femoral components; gallium scans identified 77% of infected hip prostheses.

Adult↗
PubMed1984

Magnetic resonance imaging of the chest: a diagnostic comparison with computed tomography and hilar tomography.

Computed tomography (with and without contrast enhancement) provides excellent diagnostic accuracy for the evaluation of the chest. Oblique (55 degrees) and anteroposterior hilar tomography is accurate for the evaluation of hilar nodes and masses. Magnetic resonance techniques provide excellent differentiation of vascular and nonvascular structures and therefore should be useful in the hilum and mediastinum. Magnetic resonance imaging was used in 55 patients with known pathologic conditions in the mediastinum, hilum, and lungs to determine the accuracy and efficacy of this technique compared with computed and hilar tomography. The pathologic conditions included primary and metastatic neoplasms, benign masses, vascular abnormalities, and pulmonary nodules and infiltrates. Spatial resolution with magnetic resonance imaging is less than with computed tomography with our instrument (0.15 T resistive magnet). However, in the hilum and mediastinum, magnetic resonance imaging provided diagnostic information equal to that of computed tomography with contrast in 90% of patients. Vascular and nonvascular structures were more easily differentiated than with hilar tomography. Computed tomography was far superior in the evaluation of multiple pulmonary nodules. Lesions of the chest wall were better seen with magnetic resonance imaging because of the improved soft tissue contrast.

Adolescent↗
PubMed1984

Magnetic resonance imaging of aneurysmal bone cyst.

A case of aneurysmal bone cyst is presented, and the radiographic, computed tomographic, and magnetic resonance imaging findings are discussed. The potential advantages of magnetic resonance imaging compared with those of computed tomography are explained. The case is presented to illustrate the potential value of magnetic resonance imaging in the evaluation of bone and soft tissue tumors.

Adult↗
PubMed1981

Percutaneous biliary decompression: internal and external drainage in 50 patients.

A review of percutaneous biliary decompression performed at the Mayo Clinic was initiated to study indications, technique, technical problems, and short- and long-term complications. Data were collected on the initial 50 patients in whom biliary decompression had been performed. More than 80% of patients presented with lesions or a record of previous surgery near the ductal bifurcation that resulted in increased difficulty in obtaining internal drainage. Follow-up data were available in 40 patients and allowed careful evaluation of immediate and long-term complications. Significant complications were limited to intraabdominal bleeding, which occurred in four patients and resulted in death in one. Four patients experienced sepsis immediately after the procedure, and episodes of cholangitis occurred in seven patients who had long-term drainage catheters in place.

Adult↗
PubMed1980

Transthoracic needle biopsy: accuracy and complications in relation to location and type of lesion.

Transthoracic needle biopsy has become a frequently used method for obtaining tissue for diagnosis of pulmonary lesions. The procedure carries an inherent risk of pneumothorax and hemorrhage, the latter usually manifested by transient hemoptysis. Data on 430 patients who underwent transthoracic needle aspirations from 1968 through 1977 were studied to determine accuracy and complications of this procedure as related to lesion type and location. Malilgnant disease, most often metastatic, was present in all but 10 patients. Also, 86% of patients were more than 50 years of age and most were not candidates for operation. Sufficient tissue for diagnosis was obtained in 82% of cases. The diagnostic yield diminished significantly in central lesions less than 2 cm in size. Pneumothorax and hemoptysis or pulmonary hemorrhage were the most common complications. Biopsy of central lesions, especially those in the mediastinum, were more often associated with pneumothorax, whereas lesions near the hilar region were more susceptible to hemorrhagic complications. Two deaths occurred, both from hemorrhage after biopsy in cavitating lesions with air/fluid levels. The incidence of pneumothorax was also higher in cavitating lesions. Fewer complications occurred with biopsy of lesions along the pleural surface and lesions in the periphery of the lung.

Adult↗
PubMed1978

Systemic artery-to-pulmonary vein fistula in osteogenic sarcoma of the chest wall.

An arteriovenous fistula between the systemic and pulmonary circulations may be congenital, as in bronchopulmonary sequestration, or the communication may be acquired. Inflammatory disease, trauma, and, rarely, neoplasm have been implicated as possible causes of acquired communications. We describe a patient who had a systemic artery-to-pulmonary vein fistula that was secondary to a recurrent sarcoma of the chest wall. Review of the literature failed to reveal a previous report of a similar case.

Adult↗
PubMed1976

Specificity of 99mTc-pertechnetate in scintigraphic diagnosis of Meckel's diverticulum: review of 100 cases.

Numerous reports in the recent literature have questioned the value of abdominal scanning with pertechnetate in the diagnosis of Meckel's diverticulum. In an attempt to evaluate further the specificity of pertechnetate in this condition, the clinical data and scintigrams of 100 patients with suspected Meckel's diverticulum were reviewed. The scintigram correctly identified Meckel's diverticulum before operation in seven of eight patients. One false-negative study occurred in 33 patients who underwent laparotomy. Conditions suggested as possible causes of false-positive studies (hydronephrosis, arteriovenous malformations, and intussusception) were found to give negative scans.

Adolescent↗
PubMed1975

Vesicoureteral reflux in adults.

Vesicoureteral reflux was detected in 200 adults seen in a 4 year period. In group 1 (no history of urinary tract infection and negative urine cultures), all patients had abnormalities on excretory urograms that were suggestive of reflux. In patients with a history of recurrent urinary tract infection (groups 2 and 3), the excretory urograms showed an abnormality in 79 per cent of those with negative cultures and in 83 per cent of those with positive cultures. Thus, reflux should be suspected in patients with a history of recurrent urinary tract infection even if infection cannot be documented with urine culture. Urographic evidence of renal parenchymal scarring, ureteral dilatation, or mucosal striations should also suggest the possibility of vesicoureteral reflux even when the patient may have no urinary tract symptoms. Voiding cystourethrography should be performed in all adults with these findings to exclude the possibility of vesicoureteral reflux.

Adolescent↗