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Biomedical subjects

S Saini

Publications and source records attributed to S Saini.

At least 253 records · Page 14Linked to original sources
PubMed1987

Transcystic biopsy: a new approach to posterior pelvic lesions.

Six patients with masses located posterior to the bladder were biopsied using an anterior transcystic approach. Conventional biopsy needles were introduced through the bladder with both sonographic (five) and CT guidance (one). Clinically important diagnoses of recurrent carcinoma (four) or cytology-negative fluid (two) were made in all patients. One patient had a transient episode of minimal hematuria immediately after the biopsy. Otherwise, there were no complications. Transcystic biopsy appears to be a safe and effective technique for biopsy or aspiration of posterior pelvic masses.

Biopsy, Needle↗
PubMed1987

MR imaging of splenic metastases: ferrite-enhanced detection in rats.

Detection of intrasplenic neoplasms using sonography, CT, and scintigraphy is limited by poor inherent tumor-spleen contrast relative to image noise. Despite the wide range of contrast parameters available for MR imaging, similar limitations have been found with this technique. Magnetopharmaceuticals have the ability to enhance tumor-spleen contrast and improve lesion detectability. In this study, a rodent model of cancer metastasized to the spleen was used to evaluate the potential of superparamagnetic ferrite particles as a tissue-specific reticuloendothelial contrast agent. Other studies have shown ferrite to have little or no toxicity. Without contrast material, metastatic adenocarcinoma of the spleen could not be distinguished from normal splenic parenchyma on in vivo MR images. At a dose of 50 mumol Fe/kg, the T2 relaxation time of spleen decreased by 77%, while tumor T2 was essentially unchanged (p less than .005). Intrasplenic tumors 4-6 mm in size became readily detectable on in vivo MR images after the administration of ferrite particles. Lesion conspicuity, quantitated by the tumor-spleen contrast-to-noise ratio, showed a 43-fold increase. Ferrite particles show great promise as a contrast agent to enhance the detection of focal splenic lesions.

Adenocarcinoma↗
PubMed1987

Ferrite particles: a new magnetic resonance imaging contrast agent. Lack of acute or chronic hepatotoxicity after intravenous administration.

Intravenous administration of ferrite particles may be useful as contrast agents for magnetic resonance (MR) imaging of the liver. We studied several sensitive biochemical parameters of hepatocellular function and toxicity in rats after intravenous ferrite injections to determine whether there was any evidence of iron-induced hepatotoxicity. Light microscopy and iron determinations were performed on the liver, spleen, lung, and kidney. Forty-eight hours after a massive (250 mg iron per kilogram) ferrite injection, liver, spleen, and lung nonheme iron concentrations were markedly increased. Microscopy showed this iron to be entirely in reticuloendothelial cells. Despite the large increase in hepatic iron concentration, we found no evidence of hepatic mitochondrial or microsomal lipid peroxidation or organelle dysfunction, sensitive biochemical indicators of iron-induced hepatocellular injury. At 10 to 11 weeks after administration of ferrite in smaller doses (30 mg iron per kilogram), results of all biochemical and morphologic studies were normal. Furthermore, quantitative iron determinations and microscopic studies suggest that ferrite particles may be partially degraded and that iron is cleared from the liver during a 3-month period. Because ferrite particles are taken up by reticuloendothelial cells, hepatocellular function is not impaired and iron-induced hepatocellular injury does not occur.

Animals↗
PubMed1986

Magnetic resonance imaging during acute myocardial infarction.

Experimental canine studies have demonstrated the potential of magnetic resonance imaging (MRI) for detecting and characterizing acute myocardial infarction (AMI) in humans. Accordingly, electrocardiographic-gated spin-echo MR images of the left ventricular short axis were obtained in 34 patients a mean of 11 +/- 6 days (range 3 to 30) after AMI. This imaging technique allowed division of the left ventricle into segments corresponding to the left ventricular segments on angiography. Patients were separated into 2 groups; the first 16 patients (group I) were examined using a variety of imaging techniques. Information derived from this experience resulted in a standard imaging protocol and development of criteria for the presence of AMI. The imaging protocol and interpretation criteria were used in the assessment of a subsequent group of 18 patients (group II). Of the 14 patients in group II with satisfactory image quality, all showed an increase in myocardial signal intensity consistent with an AMI. In addition, the anterior or inferior location of the abnormal MR segments corresponded to the electrocardiographic infarct location. MR segments showing increased signal intensity corresponded with severely hypokinetic or akinetic segments on the left ventriculogram in 8 patients having both procedures. In a group of volunteers who underwent imaging and whose images were interpreted in the same manner as those of the patients with AMI, 1 of 9 subjects had regional variation in myocardial signal intensity compatible with an AMI. In summary, AMI is readily detected, located and characterized by electrocardiographic-gated MRI. These findings suggest that MRI techniques may have a role in the evaluation of AMI in humans.

Adult↗
PubMed1986

Percutaneous drainage of diverticular abscess. An adjunct to surgical therapy.

We undertook this study to determine whether a computed tomography-guided, percutaneous preoperative drainage of a peridiverticular abscess can safely allow a one-stage procedure in patients requiring surgery for acute diverticulitis. In 17 patients evaluated prospectively by computed tomography, thin-needle aspiration demonstrated purulent fluid collection in 11 patients. Percutaneous catheter drainage was undertaken in eight patients. In the three remaining patients, the abscess was either too small to warrant drainage or no safe access route was present. Seven of eight patients had a single-stage resection within one to three weeks of percutaneous catheter drainage. There were no complications. Our studies suggest that a combined radiological-surgical approach has the potential to reduce morbidity and hospital costs without increasing mortality in the management of perforated colon diverticulitis with associated abscess formation.

Abscess↗
PubMed1986

Ejection fraction determination by MR imaging: comparison with left ventricular angiography.

To determine the accuracy of left ventricular ejection fractions (EFs) calculated from magnetic resonance (MR) images, 22 patients who underwent coronary angiography and left ventriculography were studied within 1-3 days by MR imaging. ECG-gated spin-echo 30-msec echo-delay images were obtained in end systole and end diastole in a plane through the long axis of the left ventricle perpendicular to the septum at a level through the aortic valve and apex. The area-length method was then used to calculate the EF from left ventriculograms and MR images. Angiographic EF correlated linearly with MR determinations. The mean differences in EF calculation between two observers were 5.0 +/- 6.9 for ventriculography and 2.7 +/- 7.8 for MR imaging. MR imaging, using image planes oriented to the left ventricular axes, can allow accurate EF calculation. This has the potential to be clinically useful in noninvasive evaluation of cardiac function.

Adult↗
PubMed1986

Detection of hepatic metastases: analysis of pulse sequence performance in MR imaging.

Forty-three patients with liver metastases were imaged using 14 different pulse sequences (average, 7.5 sequences per patient) to allow direct comparison of their performance. "T2-weighted" spin-echo (SE) images, "T1-weighted" inversion recovery (IR) images, and "T1-weighted" SE images were obtained using a wide range of timing parameters. Pulse sequence performance was quantitated by measuring liver signal-to-noise (S/N) ratios and cancer-liver signal difference-to-noise (SD/N) ratios. Data were standardized to reflect a constant imaging time of 9 minutes for all pulse sequences. The SE 2,000/120 (TR [repetition time]/TE [echo time]) sequence resulted in the greatest SD/N ratio of the T2-weighted SE sequences but also yielded the low S/N ratios, poor anatomic resolution, and motion artifacts common to all T2-weighted SE images. IR sequence images were also sensitive to motion artifacts because of the use of a long TR (1,500 msec). Short TR/TE T1-weighted SE sequences (SE 260/18) had the greatest SD/N ratio (P less than .05), S/N ratio, and anatomic resolution. Furthermore, extensive signal averaging appears to be a powerful solution to all types of motion artifacts in the abdomen.

Adenocarcinoma↗
PubMed1986

Oblique planes of section in MR imaging.

Magnetic resonance (MR) imaging allows freedom in choosing oblique planes of section and rotation of the image plane with respect to the frequency-encoded (F) and phase-encoded (P) dimensions. A general method is described for understanding geometric relationships between the fixed magnetic coordinate system, patient positioning, and the flexible observer's coordinate system. Oblique planes of section are clinically useful in studying organs with an axis of symmetry that is oblique to the magnet coordinate system, such as the heart. Rotation of the image plane can be used to move motion artifacts away from anatomic regions of interest, such as the liver and spine. Appropriate use of oblique section selection and image rotation can improve MR image quality and diagnostic value of the patient study.

Humans↗
PubMed1986

Rapid MR imaging with suspended respiration: clinical application in the liver.

The authors demonstrate that it is possible to obtain highly T1-weighted images of the abdomen using a suspended respiration partial saturation (SRPS) method in a breath-holding interval. T2*-weighted images, which reflect tissue T2 as well as variations in the static magnetic field, can also be rapidly obtained. The authors studied five healthy subjects and 19 patients with a variety of liver abnormalities, including benign and malignant hepatic neoplasms, fatty liver infiltration, ascites, and hematoma. On T1-weighted multisection acquisitions, the entire liver can be screened for mass lesions in a single 20-second breath-holding interval. Phase-contrast SRPS images are sensitive to fatty infiltration of the liver. SRPS images are more sensitive to variations in magnetic susceptibility than spin-echo images are, which has been proved to be of value in the detection of hemorrhage. With continued pulse sequence development and clinical study, this method has the potential to become the method of choice for evaluation of the upper abdomen.

Adult↗
PubMed1986

MR-guided aspiration biopsy: needle design and clinical trials.

Nonferrous needles of pure brass, titanium, or copper, and ferrous needles of different alloys of stainless steel were analyzed for the size, area, and distribution of the image artifact created when the needles were placed in a 0.6-T magnet. Results demonstrated that a stainless steel prototype needle (type 316) would be visible on magnetic resonance images and would provide an artifact similar to that seen in computed tomographic-guided biopsies. Further testing of this prototype included assessment of the effect on the artifact when changes were made in annealing properties, gauge, length, needle-tip geometry, pulse sequence, and orientation relative to the magnetic field. To date, three human liver biopsies have been successfully and safely performed using a stainless steel type 316 needle.

Aged↗
PubMed1986

Magnetic resonance imaging of thoracic aortic aneurysms: comparison with other imaging methods.

Fifteen patients with thoracic aortic aneurysms had magnetic resonance images (MRI) and at least one additional diagnostic image study: thoracic aortography, computed tomography (CT), or two-dimensional echocardiography. Twenty aneurysms were demonstrated by MRI, 19 by the other studies. One small saccular aneurysm was missed by CT. There was complete agreement between MRI and other studies regarding aneurysm morphology, and good correlation in diameter measurements of the aneurysms and at multiple additional aortic levels.

Adolescent↗
PubMed1986

Staging rectal cancer by MR and CT.

Sixteen patients with known rectal cancer were evaluated and staged with CT and MR, and at surgery. Detailed evaluation of the pathologic specimens was performed and correlated with CT and MR to determine the accuracy of staging. Most of the cases were advanced stages, and both CT and MR were equally effective in staging. Prone positioning using an air-distension technique was equally important for CT and MR examinations. Because of a positive contrast material (iodine), adequate CT examinations could be performed without prior bowel preparation; however, bowel cleansing was necessary for MR examinations. Both techniques could identify the primary tumor and invasion into perirectal fat and local organs. Neither CT nor MR were able to assess the extent of bowel-wall infiltration or tumor spread to normal size perirectal lymph nodes.

Air↗
PubMed1986

Dynamic spin-echo MRI of liver cancer using Gadolinium-DTPA: animal investigation.

An animal model of liver cancer was used to demonstrate that with a fast MRI technique, Gadolinium-DTPA increases tumor-liver contrast. A spin-echo pulse sequence with short repetition (TR) and echo-delay (TE) times (TR 250/TE 15/Excitations 1) has a scan time of 0.6 min, which allows early dynamic postcontrast infusion imaging. This is necessary to capture peak compartmental differences when an extracellular contrast agent such as Gadolinium-DTPA is used. This short TR/short TE pulse sequence also increases T1-dependent tissue contrast over the traditional (inversion recovery or spin echo) T1-weighted pulse sequences. Our studies suggest a significant potential for improved detection of liver metastases with Gadolinium-DTPA-enhanced liver MRI.

Adenocarcinoma↗
PubMed1986

Percutaneous drainage of subphrenic abscess: a review of 62 patients.

Sixty-two patients who presented with subphrenic abscesses had the abscesses drained percutaneously. Diagnosis of a subphrenic collection was usually made with sonography. Initial percutaneous drainage was accomplished with a combination of sonography and fluoroscopic guidance. More recently (in the last 31 cases) most drainages were done with sonographic guidance alone. Successful catheter drainage was achieved in 85% with a complication rate of 4.8%. Failure of catheter drainage (defined as any patient who was not cured by percutaneous drainage alone) occurred in patients with multiple collections or in whom the primary cause of the abscess necessitated surgery, for example, perforated ulcer, acute cholecystitis. Considerations for successful drainage include understanding the anatomy of the subphrenic space, recognizing the importance of a correct access route (avoidance of the pleura and lung), and the long time necessary for adequate drainage (longer than 10 days in 60%). An angled subcostal approach to the subphrenic space was used in 56 (90%) of 62 cases. No complications occurred in this group. The one pneumothorax that occurred in the remaining six cases was a direct result of using an intercostal approach through the parietal pleura into a subphrenic collection. We conclude that percutaneous drainage is a safe and effective method of treatment of subphrenic abscesses.

Catheterization↗
PubMed1986

Evaluation of Gaucher disease using magnetic resonance imaging.

Magnetic resonance imaging was used to study the skeletal involvement in a series of twenty-four patients with Gaucher disease. Many sites in the marrow of these patients were characterized by an abnormally low signal intensity that reflected shortened T1 and markedly shortened T2 values in the replaced marrow. The abnormality was non-homogeneous in distribution. In the lower extremity, the proximal (femoral) areas were more frequently affected than the distal (tibial) sites. The epiphyses were generally spared unless the involvement of bone was extensive. Lack of epiphyseal involvement on the magnetic resonance images generally precluded any suspicion of osteonecrosis. The extent of involvement, as suggested by the magnetic resonance data, appeared to correlate well with the occurrence of musculoskeletal complications. Magnetic resonance imaging is more sensitive than computerized tomography in demonstrating the extent of abnormalities in patients with Gaucher disease, and it may have prognostic value.

Adolescent↗