Showing papers in "Radiology in 1984"

Simple proton spectroscopic imaging.

Abstract: Simple modification of a spin echo imaging pulse sequence generates useful spectroscopic information at 0.35 T. New images are produced that show water only, fat only, and the difference between water and fat intensity. Imaging speed, spatial resolution, and signal-to-noise ratio are comparable with ordinary imaging. The method provides new parameters for tissue characterization and improved contrast between some organs.

Sonographic estimation of fetal weight. The value of femur length in addition to head and abdomen measurements

Abstract: Sonographic estimation of fetal weight in utero was performed in 167 live-born fetuses examined within one week of delivery. Regression models were based on measurements of abdominal circumference, head circumference, biparietal diameter, and femur length, both alone and in combination. The best results (1 S.D. = 7.5% of actual weight) were obtained by combining measurements of the fetal head, abdomen, and femur, most likely due to the strong linear relationship between femur length and crown-heel length.

Estimating fetal age: computer-assisted analysis of multiple fetal growth parameters.

Abstract: Regression models for predicting menstrual age based on real-time sonographic measurements of four fetal parameters (biparietal diameter, head circumference, abdominal circumference, and femur length), used alone and in combination, were developed in a cross-sectional study of 361 fetuses between 14 and 42 menstrual weeks. The head circumference and femur length were the strongest individual predictors of age. A number of combinations of fetal parameters, including the combination of head circumference and femur length, provided age estimates that were significantly better (p = 0.05) than those using any single parameter alone. It was also demonstrated that simply averaging individual age estimates in a given case could provide results that were not significantly different from those obtained by using the same parameters in a complex regression equation. The advantages and potential pitfalls of this system of fetal dating are discussed.

Three dimensional CT reconstruction images for craniofacial surgical planning and evaluation.

Abstract: Three dimensional reconstruction images of bony and soft tissue surfaces have improved understanding of complex facial deformities. Applied to CT studies of complex craniofacial abnormalities, this method has delineated abnormal facial soft tissue and bony morphology, facilitated surgical planning, and improved quantitative postoperative evaluation. Advanced computer-aided aircraft design techniques were adapted and applied to craniofacial surgical procedure-planning and evaluation using surface contours obtained from CT scans.

Magnetic resonance imaging of intervertebral disk disease. Clinical and pulse sequence considerations

Abstract: Sixty-five patients were examined with magnetic resonance imaging (MR) to determine what combination of operator-selectable controls would result in a thorough examination of the intervertebral disks. There were 20 normal subjects, 8 with degenerative lumbar disk disease, 27 with both degeneration and herniation, 5 with stenosis of the spinal canal, and 5 with disk space infection. T2 was significantly longer in the normal nucleus pulposus than in the degenerated disk. Based on plots of in vivo signal intensity vs. repetition time (TR) for various echo times (TE), a sagittal 30-msec. TE and a 0.25-sec. TR were used for anatomical delineation and rapid localization, while sagittal and/or axial 120-msec. TE/3-sec. TR images were used to evaluate the cerebrospinal fluid and disk. Comparison with radiographs, high-resolution CT scans, and myelograms showed that MR was the most sensitive for identification of degeneration and disk space infection, separating the normal nucleus pulposus from the annulus and degenerated disk. Herniation, stenosis of the canal, and scarring can be identified as accurately with MR as with CT or myelography.

Percutaneous drainage of 250 abdominal abscesses and fluid collections. Part I: Results, failures, and complications.

Abstract: The results of 250 percutaneous abscess and fluid drainage procedures are summarized. In 209 cases, operation was avoided and the patients were cured (83.6%). Partial success was achieved in 18 of 41 recurrences and failures; in these patients, operation was necessary, although the patient benefited from the percutaneous drainage. Cures and partial successes totaled 227/250 (90.8%). Noninfected collections were successfully drained in 31/43 cases. There were 21 failures (8.4%) and 20 recurrences (8%). These were most often due to fistulae, phlegmons, organized tissue, or underlying tumor. Twenty-six patients experienced complications (10.4%), seven of which were major (2.8%). Analysis and corrective measures for these problems (failure, recurrence, complication) and intraprocedural difficulties are discussed.

Comparison of CT and MR in 400 patients with suspected disease of the brain and cervical spinal cord.

Abstract: Magnetic resonance imaging (MR) (0.35 T) and computed tomography (CT) were compared in 400 consecutive patients with suspected disease of the brain and cervical spinal cord. Of 325 positive diagnoses, MR detected abnormality while CT was normal in 93; MR was more specific in 68; MR and CT gave equivalent information in 129; CT was more specific in 32; and CT was positive while MR was normal in 3. MR was superior to CT in detection of multiple sclerosis, subcortical arteriosclerotic encephalopathy, posterior fossa infarcts and tumors, small extra-axial fluid collections, and cervical syringomyelia. CT was preferable in evaluation of meningiomas and separation of tumor from edema. Using available sequence parameters, MR missed 3 1-cm calcified meningiomas which were clearly seen on CT. CT takes less time and may be preferable in patients with acute trauma as well as very young or elderly individuals. Thus the two studies should be considered complementary.

Pelvic organs in premenarcheal girls: real-time ultrasonography.

Abstract: Age-related changes in uterine and ovarian morphology and size were studied in 114 normal premenarcheal girls using a real-time mechanical sector scanner. Reference growth values were obtained for total uterine length, anteroposterior diameters of the corpus and cervix, corpus/cervix ratio, and uterine and ovarian volumes. Up to 7 years of age uterine size was not influenced by age and there was a relative predominance of the cervix over the corpus. Thereafter the uterus underwent a regular increase in size and the corpus gradually became larger than the cervix. Ovarian volume was relatively stable up to 5 years, when regular age-related growth started, associated with an increase in cystic functional changes in the ovary. As uterine and ovarian morphology and size are reliable indicators of the degree of sex-hormone stimulation, real-time ultrasound offers a rapid method of studying normal and abnormal pubertal development in girls.

Isolated adrenal masses in nonsmall-cell bronchogenic carcinoma.

Abstract: Computed tomography has become an important diagnostic modality in the preoperative staging of patients with bronchogenic carcinoma. The adrenal glands represent one of the most frequent sites of metastasis. Therefore, an isolated adrenal mass discovered on preoperative thoracoabdominal CT poses a diagnostic problem. Three hundred thirty patients with histologically proved nonsmall-cell bronchogenic carcinoma were evaluated. Thirty-two had adrenal masses without further evidence of disease in the abdomen. Eight of these 32 masses were metastases, 17 were proved adenomas, and seven did not undergo biopsy. Thus, in the patients with nonsmall-cell bronchogenic carcinoma, an isolated adrenal mass is more likely benign than metastatic, and biopsy is advocated prior to withholding potentially curative surgery.

Cardiac Imaging Using Gated Magnetic Resonance

Abstract: To overcome the limitations of magnetic resonance (MR) cardiac imaging using nongated data acquisition, three methods for acquiring a gating signal, which could be applied in the presence of a magnetic field, were tested: an air-filled plethysmograph, a laser-Doppler capillary perfusion flowmeter, and an electrocardiographic gating device. The gating signal was used for timing of MR imaging sequences (IS). Application of each gating method yielded significant improvements in structural MR image resolution of the beating heart, although with both plethysmography and laser-Doppler velocimetry it was difficult to obtain cardiac images from the early portion of the cardiac cycle due to an intrinsic delay between the ECG R wave and peripheral detection of the gating signal. Variations in the temporal relationship between the R wave and plethysmographic and laser-Doppler signals produced inconsistencies in the timing of IS. Since the ECG signal is virtually free of these problems, the preferable gating technique is IS synchronization with an electrocardiogram. The gated images acquired with this method provide sharp definition of internal cardiac morphology and can be temporarily referenced to end diastole and end systole or intermediate points.

Computed tomography in the evaluation of diverticulitis.

Abstract: Computed tomography (CT) was performed in 43 cases of colonic diverticulitis and compared with the contrast-enema examination (CE) in 37 patients. Findings on CT included inflammation of the pericolic fat in 98% of cases, diverticula in 84%, thickening of the colon wall in 70%, a pericolic abscess in 35%, peritonitis in 16%, a fistula in 14%, colon obstruction in 12%, and intramural sinus tracts in 9%. Secondary findings included a distant abscess in 12% and ureteral obstruction in 7%. In addition to detecting ureteral and bladder involvement and distant abscess formation, CT was preferable for demonstrating the extent of pericolic inflammation, which was underestimated with CE in 41% of patients. Differential diagnosis of the CT findings is discussed. The authors indicate that CT should be the initial procedure in patients with suspected diverticulitis, particularly when CE is contraindicated.

Magnetic resonance imaging of the lymph nodes: comparison with CT.

Abstract: This retrospective study of 144 patients was made to (a) assess the potential of magnetic resonance (MR) for demonstrating lymph nodes using spin-echo technique, (b) compare the MR results with those of CT, and (c) determine the optimal pulse-sequence interval (TR) and echo-delay time (TE) for imaging lymph nodes. The reported CT findings on normal lymph nodes were compared with MR findings in 60 patients who underwent MR imaging of the neck (20 patients), chest (20 patients), abdomen (10 patients), and pelvis (10 patients) for conditions other than lymph node disease. The results showed that CT is presently better than MR for imaging neck and abdominal lymph nodes less than 13 mm in diameter. The ability of MR to demonstrate normal-size (less than 10 mm) lymph nodes in the chest was comparable to that of CT. In addition, MR scans of 84 patients with proven abnormal lymph nodes (8 neck, 49 chest, and 27 abdomen and pelvis) were assessed: in 72 patients, these nodes had also been imaged by CT. MR and CT gave similar results with abnormal lymph nodes (greater than 13 or 15 mm), but MR displayed these nodes better because of its excellent soft-tissue contrast resolution. MR can clearly differentiate abnormal lymph nodes from normal fat, muscle, vessels, adult thymus, thyroid, and diaphragmatic crura, as well as from primary tumor and lymphoceles. Optimal demonstration of lymph nodes with MR required two sequences: one with a short TR and one with a long TR and long TE. Preliminary results indicate that MR holds great promise for the demonstration of lymph nodes in every part of the body.

Effect of gadolinium-DTPA on the magnetic relaxation times of normal and infarcted myocardium.

Abstract: Acute myocardial infarctions were produced in 11 dogs by ligation of the left anterior descending coronary artery. Twenty-four hours after ligation, 0.35 millimoles per kilogram of Gd-DTPA was injected intravenously, followed by cardiectomy either 90 seconds (3 dogs) or 5 minutes (5 dogs) later. The remaining 3 dogs had cardiectomy without injection of Gd-DTPA at 24 hours after coronary occlusion. The 3 dogs that did not receive Gd-DTPA had longer T1 and T2 relaxation times in infarcted myocardium than in normal myocardium, as measured by a 10.7-MHz magnetic resonance (MR) spectrometer. The T1 and T2 relaxation times of normal myocardium at 90 seconds postinjection of Gd-DTPA were significantly shorter (p less than 0.05) than those of the normal myocardium of animals that did not receive Gd-DTPA. At five minutes postinjection, significantly (p less than 0.01) greater T1 shortening was exhibited in the infarcted myocardium compared with adjacent normal myocardium in the dogs injected with Gd-DTPA. Thus, Gd-DTPA has differential and time-varying effects on relaxation times of normal and infarcted myocardium.

Complete cartilage-ring tracheal stenosis associated with anomalous left pulmonary artery: the ring-sling complex.

Abstract: The persistent high mortality in infants with pulmonary artery "sling" (retrotracheal anomalous left pulmonary artery) is primarily due to the coexistence in such patients of long-segment tracheal stenosis due to complete cartilage rings. Five such patients are reported. Airway studies (by filtered high-kV radiography, bronchography, and/or CT) showed low carina, horizontal equal-length right and left mainstem bronchi, and long-segment tracheal stenosis. The length of the stenosis far exceeded the contact with the pulmonary sling. The suggested term "ring-sling complex" for such patients correctly places emphasis on detection of the tracheal malformation, which currently has no satisfactory surgical treatment.

Ear, nose, and throat cancer: ultrasound diagnosis of metastasis to cervical lymph nodes.

Abstract: We present the results of a study on the value of ultrasound in the detection of metastasis to the cervical lymph nodes in connection with cancer of the ear, nose, and throat. Comparison of clinical, ultrasound, and histological findings for 100 patients who underwent surgery revealed that clinical examination had a sensitivity of 78% versus 92.6% for ultrasound. All 18 cases of thrombosis of the internal jugular vein were detected by ultrasound. Clinical staging of the disease was modified in 28 of these patients based on ultrasound findings, including three false positive findings. Ultrasonographic follow-up at three months for a second group of 110 patients who did not undergo neck dissection provided prognostic information, since lesion stability or progression was correlated with death in less than one year in 41 of 43 patients. Ultrasound is of primary value in providing information of an anatomic nature, including the detection of subclinical lymph nodes, volumetric evaluation, and determination of vascular connections, particularly detection of internal jugular venous thrombosis. Furthermore, for patients whose necks have been thickened as a result of radiotherapy, ultrasound allows assessment of local status.

Anatomy and metabolism of the normal human brain studied by magnetic resonance at 1.5 Tesla.

Abstract: Proton magnetic resonance (MR) images were obtained of the human head in magnetic fields as high as 1.5 Tesla (T) using slotted resonator high radio-frequency (RF) detection coils. The images showed no RF field penetration problems and exhibited an 11 (+/- 1)-fold improvement in signal-to-noise ratio over a .12-T imaging system. The first localized phosphorus 31, carbon 13, and proton MR chemical shift spectra recorded with surface coils from the head and body in the same instrument showed relative concentrations of phosphorus metabolites, triglycerides, and, when correlated with proton images, negligible lipid (-CH2-) signal from brain tissue on the time scale of the imaging experiment. Sugar phosphate and phosphodiester concentrations were significantly elevated in the head compared with muscle. This method should allow the combined assessment of anatomy, metabolism, and biochemistry in both the normal and diseased brain.

Primary intracranial tumor imaging: a comparison of magnetic resonance and CT.

Abstract: Twenty-six patients with primary intracranial tumors were evaluated by magnetic resonance (MR) and a comparison was made with CT findings. The SE technique with TR = 2,000 ms and TE = 56 ms was most useful in delineating normal anatomy, in differentiating gray and white matter, and in optimizing the visualization of edema. The use of TR = 500 ms optimized sensitivity to T1 relaxation time differences in disparate tissue and best defined the cerebrospinal fluid spaces. Although prolongation of T1 and T2 relaxation values was seen with most malignant lesions, several cases produced no obvious prolongation of T1. Separation of tumor from surrounding edema was possible in several instances. In 16/26 patients information not available on CT was obtained with MR. This included detection of altered tissue characteristics where CT showed only mass effect, more accurate depiction of full extent and location of tumor, and visualization of associated abnormalities. However, a small inner ear epidermoid tumor seen with high-resolution CT (1.5-mm sections) was difficult to identify with certainty on MR, and in two other cases punctate foci of calcification were not identified on MR.

Non-small-cell lung cancer: results of the New York screening program.

Abstract: Radiographs of 168 patients with non-small-cell lung cancer were reviewed. Following a negative initial examination, 102 tumors were detected during routine annual screening, while 66 were diagnosed during the interval between screenings. The cancers detected on routine yearly examination were smaller; the rate of resectability was higher, a larger number were Stage I, and survival was better. Within the routinely screened group, 65% had evidence of cancer on reviewing earlier radiographs; these patients tended to have earlier stages of cancer and a better survival rate.

Parapharyngeal space masses: an updated protocol based upon 104 cases.

Abstract: Surgical and CT examinations of 104 patients, each of whom presented with a parapharyngeal space mass, has resulted in the development of an updated CT protocol designed to provide a preoperative diagnosis. When dynamic scanning is used, diagnostic angiography or digital venous imaging (DVI) can be avoided in almost all of these cases. A specific preoperative diagnosis can be made in 88% of the patients and a limited differential diagnosis, which includes the final diagnosis, can be made in virtually all cases. The protocol and the problems encountered in differential diagnosis are presented. Evidence to suggest that minor salivary gland benign mixed tumors may arise in salivary rest tissue, rather than pharyngeal mucosal glands, is also presented.

Reflex sympathetic dystrophy in the foot: clinical and scintigraphic criteria.

Abstract: In an attempt to establish specific scintigraphic criteria for the reflex sympathetic dystrophy syndrome (RSD) as defined by a group of specialized hand surgeons, 145 consecutive patients, 23 of whom had clinical RSD, underwent three phase radionuclide bone scanning (TPBS). Specific patterns for positive radionuclide angiogram, blood pool, and delayed images were established. The delayed images were sensitive (96%), specific (97%), and had a valuable negative predictive value (99%). We concluded that TPBS could provide an objective marker for RSD, and it could also be used to exclude RSD in patients who had less specific signs and symptoms.

Sonographic evaluation of the cartilage of the knee.

Abstract: Real-time ultrasound was assessed as a means of evaluating osteoarthritis of the knee. The knee was maintained in complete flexion so as to expose the weight-bearing portion of the femoral condylar cartilage. After establishing the validity of the method in an excised bovine knee, 7 asymptomatic individuals, 10 arthritic patients, and several patients with other conditions were examined. The results indicated that sonography can be used to measure the thickness of the articular cartilage in man, as well as to detect changes in its surface and internal characteristics. Early changes of arthritis may be revealed in this manner.

Magnetic resonance of the brain: the optimal screening technique.

Abstract: Seventy consecutive patients were examined with magnetic resonance (MR) and computed tomography (CT) of the brain. Each study was independently reviewed. Focal abnormalities were detected by one or both modalities in 51 patients. Neoplastic, infectious, vascular, demyelinating, metabolic, and congenital disorders of the brain were included. The MR pulse sequence that best detected these abnormalities was a spin-echo multisection technique that used a long interval between RF excitations (TR = 1500 or 2000 msec). Forty-eight of 51 patients showed focal lesions with this technique. A supplementary MR pulse sequence with a short TR (500 msec) was useful in helping to characterize certain lesions with a long T1 relaxation component, but in 10 of 26 positive cases in which this sequence was added it would have missed the abnormality had it been the sole sequence used. MR missed focal lesions in 3 of 51 patients. These were lesions that required thin-section (1.5 mm) CT techniques. Two were intrasellar, and one...

Radiological follow-up of transluminally inserted vascular endoprostheses: an experimental study using expanding spirals.

Abstract: A technique for transluminal implantation of vascular endoprostheses was developed. Using a suitable instrument, 160 spiral-shaped prostheses of various forms and sizes were torsion-reduced in diameter and transluminally inserted under fluoroscopy in our study population consisting of 65 dogs and five calves. At the target, the spirals were enlarged and released from the carrier, whereupon they attached themselves to the vessel wall by elastic expansion. We implanted spirals into the vena cava or the thoracic and abdominal aorta, using the infrarenal aorta and the jugular or femoral vein for access. Angiography (the maximum follow-up was two years) demonstrated that the operation was reproducable and that it could be planned. Angiography also demonstrated that the position of the spiral prosthesis was stable and that the spiral did not lead to stenosis, thrombosis, or perforation, providing an adequate technique was used. The side branches of the main vessels remained patent, even with several spiral coils across their orifices. The method can be clinically implemented and lends itself to many applications in the vascular field.

Respiratory gating in magnetic resonance imaging at 0.5 Tesla.

Abstract: A device for gating the acquisition of magnetic resonance images with chest wall motion was developed, and the effects of respiratory gating upon image quality were studied. Images of respiratory gated examinations were compared with those of ungated examinations in 16 subjects. In a subset of four of those subjects, combined respiratory and cardiac gated images were obtained. Respiratory gating removed gross motion artifacts from magnetic resonance images of the chest and abdomen. Resolution of small normal tissue structures, such as the portal and hepatic veins, is improved. In cardiac studies, respiratory gating improved the visualization and definition of the atria and ventricles.

Hepatosplenic schistosomiasis mansoni: ultrasound manifestations.

Abstract: Ultrasound (US) was performed in 103 patients with hepatosplenic schistosomiasis mansoni. The abnormal US findings are reported and correlated with the pathologic and anatomic characteristics. The main US findings are periportal fibrosis, left lobe hypertrophy, thickening of the wall of the gallbladder, granulomas, splenic nodules, and widening of the portal vessel system. Frequent but nonspecific findings include splenomegaly and the presence of collateral vessels. Portal vein thrombosis was present in a few cases. It is concluded that US is a major tool in the diagnosis of this disease.

Digital image processing: effect on detectability of simulated low-contrast radiographic patterns.

Abstract: Detection studies of simulated low-contrast radiographic patterns were performed with a high-quality digital image processing system. The original images, prepared with conventional screen-film systems, were processed digitally to enhance contrast by a "windowing" technique. The detectability of simulated patterns was quantified in terms of the results of observer performance experiments by using the multiple-alternative forced-choice method. The processed images demonstrated a significant increase in observer detection performance over that for the original images. These results are related to the displayed and perceived signal-to-noise ratios derived from signal detection theory. The improvement in detectability is ascribed to a reduction in the relative magnitude of the human observer's "internal" noise after image processing. The measured dependence of threshold signal contrast on object size and noise level is accounted for by a statistical decision theory model that includes internal noise.

Percutaneous transluminal angioplasty of the renal artery. Results and long-term follow-up.

Abstract: Percutaneous transluminal angioplasty (PTA) was used to treat 109 patients with 141 renal artery stenoses, including 58 patients in whom medical management was unsuccessful. The initial success rate was 94%. Fifty-five patients had severe diffuse atherosclerosis and 40 had renal insufficiency. Thus far, 36 patients (50 stenoses) have undergone a total of 52 follow-up angiographic studies. Clinical data, including blood pressure response, were obtained in all cases. Only 7 of the 98 hypertensive patients failed to respond to PTA. Of the 11 patients treated primarily for renal insufficiency, 5 improved. Of the 29 hypertensive patients who also had elevated BUN and creatinine, renal function improved in 13. Altogether, 96 patients (88%) benefited from the procedure. Analysis of long-term results suggests that PTA should be the treatment of choice for fibromuscular dysplasia and short, segmental atherosclerotic lesions and could also prove helpful in improving renal insufficiency.

The effect of motion on two-dimensional Fourier transformation magnetic resonance images.

Abstract: The effect of motion on two-dimensional Fourier transformation magnetic resonance (MR) images was investigated using phantoms, animals, and normal volunteers. All images were obtained with a 0.30-Tesla superconducting magnet using spin echo pulse sequences. Respiratory motion was simulated while imaging the phantoms. In addition to image blurring, motion produced ghost images, or image harmonics. These ghost images were copies of the static image that was produced at periodic intervals. Canine images, which were obtained during respiration and after the administration of curare, showed significant improvement after respiratory motion was eliminated. Images of normal volunteers were improved with respiratory and cardiac gating, but data acquisition time was significantly increased. These results indicate that MR image quality could be improved with a system that acquires all necessary data within a single breathhold .

Acute myocardial ischemia: magnetic resonance contrast enhancement with gadolinium-DTPA.

Abstract: Gadolinium-DTPA (Gd-DTPA) was used to improve the diagnostic utility of magnetic resonance (MR) in detecting early ischemia, before the onset of infarction Following one minute of left anterior descending coronary artery occlusion, 9 dogs were intravenously injected with either 05 mM/kg of Gd-DTPA (6 dogs) or normal saline (3 dogs) One more minute was allowed for perfusion of injectate prior to cardiectomy and MR imaging of the ex situ heart There was no visible difference in intensity or alterations in magnetic relaxation times between normal and ischemic myocardium in the control (saline-injected) animals The Gd-DTPA-injected dogs had a well-defined segment of high intensity representing the ischemic myocardium in the anterior wall of the left ventricle, due to significant T2 relaxation rate enhancement in the adjacent normal myocardium Both T1 and T2 were significantly (p less than 001) shortened in the normal myocardium of the Gd-DTPA animals, but relatively greater T2 relaxation rate enhanceme