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J D Godwin

Publications and source records attributed to J D Godwin.

At least 37 records · Page 2Linked to original sources
PubMed1994

Predictive respiratory gating: a new method to reduce motion artifacts on CT scans.

PURPOSE: To evaluate a gating system, called predictive respiratory gating (PRG), that reduces motion-induced artifacts on computed tomographic (CT) scans of patients who cannot suspend respiration. MATERIALS AND METHODS: PRG uses a respiration monitor and a new algorithm to predict when a motionless period is about to occur. It automatically starts scanning so the scan is temporally centered around the motionless period at end inspiration or end expiration. To demonstrate PRG, CT was performed on a motion phantom and a quietly breathing volunteer with and without gating. RESULTS: Scans of the phantom obtained with PRG contained less motion-induced streaking and blurring than did scans acquired without PRG. Scans of the volunteer gated at end expiration contained significantly less artifact than nongated scans (P < .03). CONCLUSION: PRG reduced motion artifact on scans of a spontaneously breathing volunteer. PRG may be able to reduce motion artifacts on scans of patients unable to suspend respiration.

Adult↗
PubMed1994

Panlobular pulmonary emphysema caused by i.v. injection of methylphenidate (Ritalin): findings on chest radiographs and CT scans.

OBJECTIVE: Recent reports have described severe precocious pulmonary emphysema in persons who inject methylphenidate (crushed Ritalin tablets) i.v. We retrospectively evaluated the plain radiographic and CT features in 21 such patients. MATERIALS AND METHODS: The chest radiographs, available CT scans, and clinical and pathologic data were reviewed in 21 cases of i.v. Ritalin use. The patients were from 35 to 54 years old. Twelve patients were men, and nine were women. Emphysema was graded on the basis of findings on chest radiographs, by consensus, on a four-point scale as absent, mild, moderate, or severe. CT scans were available for three patients, including one imaged after a single lung transplantation. Autopsy results were available for four patients. Fixed inflated lung specimens and corresponding high-resolution CT scans were available in three cases. RESULTS: Radiographs showed pulmonary emphysema in all cases. The distribution of disease was basilar and symmetric. Small apical bullae were suggested in only one case. Basilar emphysema was rated as mild in four patients, moderate in three patients, and severe in 14 patients. In 11 patients who had serial chest radiographs, the basilar emphysema was noted to progress over a 2- to 7-year period. No evidence of progressive massive fibrosis was seen in any patient. CT scans confirmed emphysema, most severe at the lung bases. CONCLUSION: The plain radiographic and CT findings in patients who inject Ritalin are similar to those found in patients with alpha 1-antitrypsin deficiency and different from the findings seen in other types of i.v. drug use. The finding of basilar pulmonary emphysema should alert the radiologist to the possibility of i.v. injection of Ritalin.

Adult↗
PubMed1994

Radiographic changes in acute exacerbations of cystic fibrosis in adults: a pilot study.

OBJECTIVE: We set out to determine whether specific findings can be seen on chest radiographs of adult patients with cystic fibrosis who are having acute exacerbation of respiratory disease. MATERIALS AND METHODS: Over a 2-year period, 22 adults with cystic fibrosis had both a baseline chest radiograph and a radiograph obtained either because of acute exacerbation or for some other reason (nonexacerbation). Fourteen radiographic features, including mucous plugs, air-space disease, peribronchial thickening, bronchiectasis, fluid levels, and lymphadenopathy, were scored retrospectively by two radiologists, who did not have knowledge of the patient's clinical condition, as being present, absent, increased, decreased, or unchanged. An overall assessment (better, worse, or no change) was also given for each radiograph. Data were analyzed in two ways (per individual episode and per individual patient) by using contingency tables, with statistical significance determined by exact permutation testing. RESULTS: Of the 22 patients, 13 had 29 exacerbations and eight had 11 nonexacerbations. The remaining patient had radiographs showing both an exacerbation and a nonexacerbation. With the exception of overall change (p = .06), none of the radiographic variables showed a statistically significant association with exacerbation (mean p value, .66; range, .19-.90). CONCLUSION: The 14 specific radiographic findings studied, including peribronchial thickening, mucous plugs, air-space disease, and fluid levels, were not useful in determining whether an adult patient with cystic fibrosis was having acute exacerbation of the disease. With regard to these individual variables, chest radiographs are not helpful in the management of acute exacerbation of cystic fibrosis in adults. However, overall change approached statistical significance (p = .06). The value of chest radiography lies more in excluding the rare major complication, such as pneumothorax, than in diagnosing the usual exacerbation.

Acute Disease↗
PubMed1993

Growth potential of the transplanted lung in the infant primate.

Success in neonatal lung transplantation depends on the growth of the transplanted lung. To study the effects of transplantation and denervation on primate lung growth without rejection or immunosuppression, an autotransplant model was chosen. Eight-week-old baboons underwent left lung autotransplantation (n = 5) or sham operation (n = 1). At age 13 weeks and 9 months, single lung volumes were calculated by nitrogen washout and computed tomography. Results were compared with those of 4 unoperated weight-matched controls (2 per age group). Over the growth period, mean total lung capacity in operated baboons increased 82% (137 to 249 mL) by nitrogen washout and 70% (182 to 309 mL) by computed tomography compared with 85% (128 to 237 mL) and 74% (141 to 245 mL) for the sham-operated baboon, respectively. Transplanted left lung volume increased 91% (53 to 101 mL) by nitrogen washout and 75% (68 to 119 mL) by computed tomography compared with 85% (54 to 100 mL) and 80% (56 to 101 mL) for the sham-operated baboon, respectively. In the absence of rejection and immunosuppression, normal volume growth occurs in the transplanted infant primate lung.

Animals↗
PubMed1993

Extrapleural fat collections: pseudotumors and other confusing manifestations.

Because thoracic fat is mobile and plastic, it can assume a variety of shapes and distributions. Fat collections can be confusing, and some can even mimic tumors. This essay highlights the variable and potentially confusing manifestations of normal thoracic fat on plain radiographs and CT scans. It does not emphasize fatty tumors, ordinary mediastinal lipomatosis, costal fat pads, or diaphragmatic hernias, as these topics have been reviewed recently.

Adipose Tissue↗
PubMed1992

Thoracic actinomycosis: CT findings in eight patients.

The chest radiographs and computed tomographic (CT) scans obtained in eight patients with pathologically proved cases of thoracic actinomycosis were independently reviewed by two observers. All patients were alcoholic men aged 42-62 years. Air-space consolidation, seen on the radiograph and CT scan in each case, was present in the lower lobes in seven patients (88%) and upper lobes in three (38%). Pleural effusion was present in five (62%). Pleural thickening adjacent to the air-space consolidation was identified on the radiograph in four (50%) and CT scan in all eight. Cavitation or central areas of low attenuation not apparent on the radiograph were seen on the CT scan in five cases (62%). Hilar or mediastinal lymphadenopathy was identified on the radiograph in three cases (38%) and on the CT scan in six (75%). Chest-wall invasion occurred in only one case (12%). Thoracic actinomycosis is characterized on CT scans by air-space consolidation with adjacent pleural thickening. CT is superior to radiography in assessing the thoracic manifestations of actinomycosis.

Actinomycosis↗
PubMed1992

Minimum scan speeds for suppression of motion artifacts in CT.

Cardiac and ventilatory motions cause artifacts at chest computed tomography (CT). To determine how short the scan times on third-generation units must be to avoid such artifacts, motion was measured with fast and ultrafast CT scans. Minimum detectable motion was then determined. The longest scan time that avoided a barely perceptible artifact was calculated by dividing the minimum detectable motion by the peak physiologic velocity. The posterior left ventricular wall moved at a maximum velocity of 52.5 mm/sec, necessitating a scan time of 19.1 msec or less to avoid artifact. Lung vessels near the heart moved at 40.5 mm/sec for a scan time of 24.7 msec or less. During quiet breathing, pulmonary vessels moved at 10.7 mm/sec for a scan time of 93.5 msec or less. The authors conclude that the shortest scan time on third-generation units (0.6 second) cannot prevent all artifacts arising from motion in the chest. Even ultrafast scan times (50 msec) are not short enough to eliminate artifacts on these units. Thus, reduction of motion artifacts will require techniques other than fast scanning.

Artifacts↗
PubMed1992

Swyer-James syndrome: CT findings in eight patients.

To determine the importance of chest CT findings in patients with Swyer-James syndrome (unilateral small lung with air trapping) and to compare these findings with those on chest radiographs and scintigrams, we reviewed the CT scans, chest radiographs, and scintigrams of eight patients with the syndrome. Radiographs showed unilateral hyperlucency in seven patients and bilateral asymmetric hyperlucency in one. CT showed that the hyperlucency was unilateral in only three and that hyperlucency in one. CT showed that the hyperlucency was unilateral in only three and that hyperlucent regions on radiographs contained patches of normal lung attenuation in five patients. Conversely, in four patients, CT also showed small hyperlucencies in regions considered normal on radiographs. These lucencies usually had poorly defined margins and irregular shapes (five patients), but sometimes were peripheral, wedge shaped, and sharply demarcated (two patients). CT also showed subtle abnormalities not visible on radionuclide scans in two patients. Air trapping in hyperlucent regions was confirmed by a lack of change in volume on expiratory CT scans in five cases. Bronchiectasis was found in only three patients. CT helps to exclude central bronchial obstruction, cysts, and vascular disease as causes of hyperlucency. By excluding central obstruction, CT may make bronchoscopy unnecessary in some patients. CT is more sensitive than radiographs and radionuclide scans in detecting hyperlucent regions and in showing their distribution. Our experience suggests that bronchiectasis is not a necessary component of the Swyer-James syndrome.

Adolescent↗
PubMed1992

Wegener's granulomatosis: findings from computed tomography of the chest in 10 patients.

Radiographs and computed tomography (CT) scans of the chest were reviewed for 10 patients with pathologically proven Wegener's granulomatosis. The CT scans revealed multiple pulmonary nodules in seven patients and a single nodule in one. The nodules ranged in diameter from 2 mm to 7 cm, and most had irregular margins. All of the nodules larger than 2 cm in diameter showed evidence of cavitation in the CT scans. Additional CT findings included associated areas of consolidation (in two patients), pleural thickening (in two) and pleural effusion (in two). Chest radiographs were available for eight patients, and the CT scans contributed information additional to that available from the radiographs for seven of these. In one patient lung nodules were visible in the CT scans but could not be distinguished from surrounding areas of consolidation in the chest radiographs. CT revealed additional nodules in five of the six patients in whom multiple nodules were seen in chest radiographs and in one of these also revealed cavitation tht was not visible in plain radiographs. CT excluded the possibility of a nodule that was suspected from the chest radiographs in a patient who had been treated previously for Wegener's granulomatosis. The authors conclude that Wegener's granulomatosis is characterized in CT scans by multiple nodules with irregular margins and by cavitation in nodules larger than 2 cm in diameter. CT may also demonstrate nodules and cavitation not apparent in radiographs.

Adolescent↗
PubMed1991

The airway.

Explore the source record for details and available documents.

Bronchial Diseases↗
PubMed1991

Lung abscess caused by Rhodococcus equi.

In the immunocompromised patient, early diagnosis of a lung cavity is essential for appropriate treatment. Rhodococcus equi (formerly Corynebacterium equi) is a variably acid-fast bacterium that can produce cavitary disease in an immunocompromised host. The two cases presented here demonstrate the clinical and radiographic features of R equi lung abscess. The first patient was on long-term corticosteroid therapy for rheumatoid arthritis. The second patient had AIDS. The correct diagnosis in both cases was delayed because acid-fast bacilli seen on smears of sputum were presumed to be Mycobacterium tuberculosis.

Actinomycetales Infections↗
PubMed1991

Panlobular emphysema in young intravenous Ritalin abusers.

We studied a distinctive group of young intravenous Ritalin abusers with profound obstructive lung disease. Clinically, they seemed to have severe emphysema, but the pathologic basis of their symptoms had not been investigated previously. Seven patients have died and been autopsied: in four, the lungs were fixed, inflated, dried, and examined in detail radiologically, grossly, microscopically, and by electron probe X-ray microanalysis. All seven patients had severe panlobular (panacinar) emphysema that tended to be more severe in the lower lung zones and that was associated with microscopic talc granulomas. Vascular involvement by talc granulomas was variable, but significant interstitial fibrosis was not present. Five patients were tested for alpha-1-antitrypsin deficiency and found to be normal, as were six similar living patients. These findings indicate that some intravenous drug abusers develop emphysema that clinically, radiologically, and pathologically resembles that caused by alpha-1-antitrypsin deficiency but which must have a different pathogenesis. Talc from the Ritalin tablets may be important, but the mechanism remains to be elucidated.

Adult↗
PubMed1991

The extrapleural fat in empyema: CT appearance.

Pleural empyema can be accompanied by changes in the adjacent chest wall. We examined the chest wall on computed tomographic scans in 24 patients with pleural effusions. Eighteen patients had pleural empyema and six had transudative effusions. Of the 18 empyema patients, 13 had abnormally high attenuation in the extrapleural tissues. In 12 of these 13, the high attenuation was probably caused by reaction to the pleural infection. In two, it was probably caused by haematoma (one patient had haematoma and empyema). In five patients there was either no clear abnormality in the extrapleural space or an insufficient amount of fat to permit detection of an abnormality, or the parietal pleura could not be distinguished from the pleural fluid because intravenous contrast medium was not given. Of the six patients with proven transudative pleural effusions, all had extrapleural fat which appeared normal. Abnormally high attenuation in the extrapleural tissues can be expected to accompany exudative pleural effusion, particularly empyema, but not transudative effusion.

Adipose Tissue↗
PubMed1991

Computed tomography of air-space disease.

Although computed tomography (CT) has not been used as often in air-space diseases as in interstitial ones, it often provides useful information. Diseases such as early opportunistic pneumonia may be detected by CT before becoming visible on plain radiographs. Also, extent and location are often better defined by CT than by plain radiographs. Accompanying abnormalities such as abscess, lymphadenopathy, and pleural effusion are often clearly demonstrated by CT. This article reviews the CT findings in a variety of air-space diseases, including pneumonia and other infections, radiation pneumonitis and fibrosis, embolism, eosinophilic pneumonia, alveolar proteinosis, bronchioloalveolar carcinoma, lipoid pneumonitis, sarcoidosis, and trauma.

Air↗
PubMed1991

Radiographic changes in cardiac contours following heart transplantation. Clarification by MR imaging.

Chest radiographs of 46 patients who had undergone heart transplantation were reviewed with special attention to abnormalities of the cardiac contours. MR imaging in 3 such patients revealed 3 types of double right cardiac contours: the recipient right atrium combined with the donor right atrium; the donor right atrium combined with the recipient left atrium; and a cardiac fat pad combined with the right atrium. A prominent main pulmonary artery was shown by MR imaging to result from leftward displacement of the main pulmonary artery caused by clockwise rotation and transverse position of the transplanted heart. Recognition of these unique radiographic appearances is of value in assessing transplanted hearts and in avoiding misdiagnosis.

Adolescent↗
PubMed1990

Preliminary experience with portable digital imaging for intensive care radiography.

A digital radiography system based on reusable, photostimulable phosphor technology was evaluated in approximately 3,500 portable chest radiographs of patients in an intensive care unit. The system functioned well in this application. No major problems were encountered in the visualization of tubes or catheters or in the detection of pneumothoraces. Assessment of fluid volume status or the presence of small pleural effusions, especially when these were bilateral, was initially somewhat difficult but became easier as investigators became familiar with the system. Radiologists were quicker than nonradiologists to accept the minimized two-on-one display format. Critical evaluation of the overall performance of digital systems such as this one is needed for a better definition of the system's strengths and weaknesses. Specifically, statistical analyses of the ability to detect disease states such as pneumothoraces, interstitial lung disease, lung nodules, and pleural abnormalities need to be performed.

Aged↗
PubMed1990

Conventional CT of the aorta.

The advent of CT has changed the way thoracic aortic aneurysms and dissections are evaluated. In many cases, CT is the only roentgenographic examination needed beyond plain radiograph. In evaluating aneurysm. CT's advantage over aortography is that it shows the wall and the mural thrombus, not just the contrast column. In some cases of aneurysm, however, particularly those arising near the aortic arch, aortography may be necessary to establish the precise location of the lesion with respect to the brachiocephalic arteries. In evaluating dissection, CT is less invasive and at least as accurate as aortography. As with aortography, the classic findings are contrast-filled multiple channels with intervening intimal flap(s). CT's particular advantage over aortography is that it permits diagnosis of dissection when blood in the false channel is clotted rather than free-flowing. In this case, the diagnosis can be made by demonstrating displaced intimal calcifications or the high-attenuation thrombus in the aortic wall or periaortic tissues. In cases of acute dissection for which emergency surgery is considered, however, aortography is preferred to CT because CT cannot provide information about aortic insufficiency or the condition of critical arterial branches such as the coronary, brachiocephalic, mesenteric, and renal arteries. In follow-up of treated aortic dissection CT is preferred over aortography because it is noninvasive and more informative. Compared with MRI, CT has the advantages of greater reliability and of compatibility with life-support apparatus. MRI is not able to depict calcification, so any displacement of calcification cannot be detected. MRI is most suitable for follow-up of treated patients or for acute patients who are stable or who cannot tolerate intravenous contrast agents. A flexible approach is essential in choosing the appropriate radiographic tests in the work-up of aortic dissection. In this article, a workable strategy is outlined, but the radiologist should not hesitate to change the order of tests or use a second test if results from one test are confusing or inconsistent with other clinical data.

Aortic Dissection↗