Biomedical subjects
Publications and source records attributed to H R Shah.
The atypical appearance of a gas-containing, noninfected, popliteal synovial cyst has been presented. The case again demonstrates the value of plain radiographs, in this instance in distinguishing gas bubbles and calcification, which may not be apparent by MRI and ultrasound. The uniqueness of this case is stressed. The cause of the gas bubbles was not ascertained.
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The accuracy of prenatal diagnosis has become increasingly critical in the field of high-risk obstetrics. Although ultrasound (US) provides adequate information in most cases and continues to be the initial prenatal examination of choice, there are instances in which the results of the US study may be equivocal. The role of magnetic resonance (MR) imaging was explored in 27 selected patients with various indications to determine its effectiveness as a complement to US. MR imaging was most helpful in the diagnosis of extrauterine gestation, evaluation of placental position, determination of extent or nature of masses associated with pregnancy, and differentiation between diaphragmatic hernia and a thoracic mass. Although MR imaging did not add information that affected the accuracy of the diagnosis of oligohydramnios, in all other cases it provided an extra dimension in diagnosis by showing clearer anatomic relationships in the pelvis. It has proved to be a valuable complement to an equivocal US study.
Pulmonary artery aneurysm is a rare condition. We have presented what we believe to be the first case in the English literature to be diagnosed by magnetic resonance imaging.
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In selected cases CT and MRI may be useful for the evaluation of patients suspected of having central pulmonary emboli. In stable patients MRI appears to be superior to CT because no iodinated contrast medium is required. In evaluating critically ill patients CT is better because of its superior resolution, ability to assess changes in the lung parenchyma, and ease of patient monitoring.
The two cases we have reported demonstrate that dramatic enlargement of the azygos vein may occur in patients with azygos continuation of the inferior vena cava. Awareness of this phenomenon can prevent unnecessary procedures. The diagnosis should be established by dynamic CT scan.
The diagnosis of infection in prosthetic vascular grafts is difficult clinically but very important due to the high associated morbidity and mortality. Various radiographic and imaging procedures have been used. 111In-labeled white cells have been used with a sensitivity approaching 100% and a specificity of approximately 90%. Computed tomography (CT) has also been advocated as a means of detecting these infections by some. Similarly, ultrasound has been used. More recently, magnetic resonance imaging (MRI) has been advocated in hopes that the signal of the infected graft would differ from that of the noninfected graft. This article reviews the data supporting each of these modalities.
Bronchogenic cysts are relatively uncommon congenital lesions. They may be detected on routine radiography in asymptomatic patients or may present with various manifestations, some of which may be life-threatening. Age at diagnosis ranges from infancy to late adulthood, with asymptomatic lesions occurring more often in older children and adults. Cysts may be located in subcarinal, paratracheal, hilar, paraesophageal and intrapulmonary sites. The chest radiograph is the primary diagnostic study, with computed tomographic scans of the chest providing more definitive evaluation. Despite some controversy, surgery is considered the treatment of choice, even in the asymptomatic patient.
A case of type I (type A) aortic dissection proved by postmortem examination could not be fully delineated relative to the type of dissection by dynamic CT as well as three positive contrast aortograms. Small tears in the ascending aorta and their strategic locations can escape even intensive radiologic evaluation. We present a case in which medical therapy was provided and, inappropriately, surgery was not performed.
We have reported a case of a hyperdense parapelvic renal cyst that could not be easily differentiated from a solid tumor by multiple diagnostic studies. However, the typical findings of a hyperdense parapelvic cyst may allow less aggressive surgery.
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A patient sustained a gunshot injury to the spleen. The spleen was left intact in an attempt to maintain normal immune function in the patient. The patient developed a splenic abscess as a result of the injury, a complication of splenic salvage that we have not found reported before. The abscess was treated successfully via CT-guided percutaneous drainage.
Transvenous inferior vena caval filters were placed in 32 patients (21 bird's nest [BN] and 11 Kimray-Greenfield [K-G] filters). Positive contrast cavography was performed before and immediately after filter placement as well as during long-term follow-up studies. In 23 patients, computed tomographic (CT) scanning was also performed; in 10 patients, real-time ultrasound (US) study was used as an adjunct. CT scans of the BN filter showed one case of hemorrhage and one case of air embolism, both of which were not recognized at cavography. CT scanning of the K-G filter demonstrated two cases of deep penetration of the prongs and one large retroperitoneal hematoma. Real-time US scanning played a major role in checking the final position of the filter and in determining its stability during repositioning of the upper prongs of one BN filter. Noninvasive examinations, including CT and US scanning, are valuable adjuncts in immediate and long-term follow-up study of patients with inferior vena caval filters.
Making a clinical diagnosis of infection in prosthetic vascular grafts is difficult but when undiagnosed, this condition has a high mortality rate. Using Indium-111-labeled white-blood cells, 30 scans were performed in 21 patients suspected of having a prosthetic graft infection. The diagnosis of infected graft was confirmed by surgery in all cases, and lack of infection was established by resolution of symptoms with conservative therapy. Twenty-four hour scans of autologous Indium-111 leukocytes were obtained, and correlative CT studies were done in 11 cases. There were 13 infected grafts at surgery (purulent material present), and scans were positive in all (100% sensitivity); of 17 scans, there were 15 true negatives and two false positives (88% specificity). Using the criteria of gas or fluid around the graft, the sensitivity of CT was only 37% in a small subset of these patients. One-half of the cases in which infection was suspected clinically had no infection and had negative scans. Various types of grafts and graft materials were used, and there was no correlation with presence or absence of infection on the basis of the type of graft. Extragraft infection sites were found in five patients. In conclusion, use of Indium-111 leukocytes has been found to be an accurate and valuable diagnostic method for evaluation of suspected prosthetic vascular graft infection, and to have higher diagnostic accuracy than CT.
We studied 98 kidneys in 55 patients with bone scintiscans and renal sonography. Among the 29 kidneys in which hydronephrosis was suspected on bone scintiscans only 12 were truly hydronephrotic by renal ultrasound. In the other 17 cases extrarenal pelves, postural stasis, early urinary tract obstruction or renal parenchymal disease may have contributed to the discrepant findings. By ultrasound criteria there were no false negative readings for hydronephrosis on scintiscan. While it is safe to interpret absence of hydronephrosis caution should be used in diagnosing hydronephrosis, since less than half of the cases actually will have the disease when suspected on a bone scintiscan.
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The development of a right hemothorax as the result of a ruptured thoracoabdominal aneurysm is an uncommon and usually fatal event. Survival depends upon an accurate diagnosis and prompt surgical intervention. We present a case of a ruptured thoracoabdominal aneurysm into the right chest that presented as opacification of the right hemithorax and hypotension. An early CT scan provided the correct preoperative diagnosis, although the patient did not survive.