Biomedical subjects

R Nyman

Publications and source records attributed to R Nyman.

At least 37 records · Page 2Linked to original sources

PubMed1995

Budd-Chiari syndrome misinterpreted as an infiltrating liver mass. A case report.

A case of Budd-Chiari syndrome (BCS), due to hepatic venous blockage, was initially misinterpreted on CT and ultrasonography (US) as an infiltrating mass of the liver. The irregular enlargement on US and the irregular enhancement with large hypodense areas on CT were believed to be due to an infiltrating mass. US-guided biopsy suggested BCS by showing central liver congestion without any signs of tumor growth. The diagnosis was confirmed by hepatic venography demonstrating collateral veins with a typical spiderweb appearance. BCS is a rare, often lethal, condition and in order to reach an early and accurate diagnosis it is essential to be aware of the syndrome.

Biopsy↗

PubMed1995

Fine needle aspiration biopsy of hydatid cysts.

Fine needle aspiration biopsy (FNAB) was performed in 31 patients with hydatid disease by 15 operators in 41 biopsy events during the period 1983-93. The FNABs were unintentionally done without prior clinical suspicion of hydatid cysts (HCs) in 18 patients and intentionally (with prior clinical suspicion of HC) in 13 patients for pathologic confirmation required for specific therapy. The FNABs were performed with the guidance of fluoroscopy (n = 7), CT (n = 14) or ultrasonography (n = 10). The material included both closed, open and ruptured HCs from different locations such as abdomen, thorax, spine and bone. Pathologic confirmation of HC was achieved by recovering and demonstrating parasitic material in the specimen. In only 7 of 31 patients were the specimens diagnostic at the initial interpretation. This emphasizes the importance of alerting the pathologist about the possibility of hydatid disease. In 25 of 31 patients (81%) no biopsy reactions occurred. In 5 patients minor allergic reactions occurred and 3 had filling of air into intrathoracic cysts not requiring therapy. One patient, with a FNAB of a liver HC, had a sudden severe drop in blood pressure, which required anti-shock therapy with subsequent recovery without sequelae. All complications occurred with non-intentional biopsy of HC. Suggestions for diagnostic and therapeutic management of patients with HC and advice to avoid or limit potential complications or spread of disease are given where a planned biopsy is necessary for appropriate and effective therapy.

Biopsy, Needle↗

PubMed1995

Imaging of solid kidney tumours in children.

Eighteen children aged 6 months to 12 years with 20 solid renal tumours: 13 Wilms' tumours (WT), 2 clear cell sarcomas of the kidney, 1 malignant rhabdoid tumour of the kidney and 2 cases of bilateral nephroblastomatosis with Wilms' tumour underwent evaluation with US, CT and MR imaging. Contrast-enhanced CT and non-enhanced MR were equally accurate in determining the size and origin of the tumour but were unreliable in separation of stages I, II and III. US could only accurately assess the size of the tumours. MR characteristics varied somewhat between WTs and non-WTs but contrast-enhanced MR imaging might be useful for separation of WTs from nephroblastomatosis.

Child↗

PubMed1995

MR imaging of multiple myeloma in tumour mass measurement at diagnosis and during treatment.

The bone marrow of the spine, pelvis and proximal femora was examined with MR imaging at diagnosis in 30 cases of multiple myeloma (MM), and during treatment on 69 occasions. The MR pattern was normal, focal or diffuse and correlated to stage. A tumour mass index (TMI) was calculated by estimating the total myeloma mass visualised at MR imaging. The TMI correlated significantly with stage, lytic bone lesions, serum calcium, serum beta-2-microglobulin and survival. No abnormalities were seen at MR investigation in 4 of 6 patients classified as stage II because of osteoporosis only. Therapy efficacy evaluation with MR imaging corresponded to clinical evaluation on 54 of the 69 occasions. MR examination of bone marrow in MM patients can be used for tumour mass assessment, both at diagnosis and during follow-up. Valuable information can be obtained when the tumour mass is difficult to estimate using clinical criteria, e.g. in non-secretory MM or when osteoporosis is the only variable indicating an increase in the tumour mass.

Aged↗

PubMed1994

Wegener's granulomatosis limited to the kidney as a masslike lesion.

We report on a 45-year-old female who presented with end-stage renal disease due to Wegener's granulomatosis limited to the kidneys. Ultrasonography and computed tomography revealed a masslike expansion involving the upper pole of an otherwise small right kidney. Histopathology of a nephrectomy specimen revealed cystic dilatation of renal tubules and active lesions of Wegener's granulomatosis in the upper pole. The lower part of the kidney showed atrophic changes. Wegener's granulomatosis presenting as a renal mass is extremely rare. Only 3 cases have been previously reported in the literature. Wegener's granulomatosis only limited to the kidney is also rare. A brief review of 23 previously reported cases who initially presented with renal disease is presented. All but 2 patients subsequently manifested extrarenal lesions. Our patient continues to be free of any extrarenal involvement 18 months following presentation, although subsequent development of extrarenal lesions cannot be ruled out.

Adolescent↗

PubMed1994

Gd-DTPA-enhanced MR imaging in mediastinal Hodgkin's disease.

Gd-DTPA-enhanced MR imaging of 15 patients with primary mediastinal Hodgkin's disease was done before, during and after treatment. A total of 43 MR examinations were performed. After successful treatment, 13 patients had residual masses with reduced signal intensity (SI) ratio in the T2-weighted images. The majority of these also had decreased contrast enhancement as compared with the corresponding primary tumour. There was a significant positive correlation between the contrast enhancement and the SI ratios in the T2-weighted images of the primary tumours and/or the residual masses. Necrosis was seen in 3 of the primary tumours and one patient had a cystic residual mass. These necrotic/cystic lesions were easier to detect with the use of Gd-DTPA. Low SI ratio in the T2-weighted image and low contrast enhancement of the residual mass seem to indicate residual inactivity. Gd-DTPA facilitates the differentiation between cystic/necrotic and solid lesions.

Adolescent↗

PubMed1994

Accuracy of double contrast barium enema and sigmoideoscopy in the detection of polyps in patients with diverticulosis.

The sensitivity between double contrast barium enema (DCBE) and sigmoideoscopy in diagnosing neoplastic lesions in the sigmoid colon was compared in patients with diverticulosis. In 52 patients with severe diverticulosis (> or = 15 diverticulas) the DCBE detected one out of 4 polyps found by sigmoideoscopy. In the remaining 54 patients with mild diverticulosis (< 15 diverticulas) DCBE detected 7 out of 10 polyps found by sigmoideoscopy. Successful bowel preparation did not influence the outcome of the DCBE. Sigmoideoscopy was incomplete in 17 (16%) of the patients; females were more difficult to examine than males (p = 0.012), as were those with a previous pelvic operation (p = 0.032). We conclude that neither DCBE nor sigmoideoscopy alone is sufficient to detect all neoplastic lesions in the sigmoid colon in patients with sigmoid diverticulosis of the colon.

Adult↗

PubMed1994

Paraesophageal varices presenting as a retrocardiac mediastinal mass. A case report.

This report is a reminder that portal hypertension with paraesophageal varices can present as a retrocardiac mass on the chest radiograph. Schistosoma mansoni, the probable etiology in this case, causes periportal fibrosis and is the most common explanation for portal hypertension worldwide. Modern imaging techniques were most helpful in the diagnostic work-up, ultrasonography revealing pathognomonic hyperechoic periportal bands, and CT and MR imaging showing the extent of collaterals.

Diagnosis, Differential↗

PubMed1993

Detection of breast cancer metastases in the cervical spine.

Thirty women with breast cancer and indications of possible cervical spine metastases underwent skeletal scintigraphy, conventional radiography, MR imaging and CT. By combining all examinations a diagnosis was settled in each patient and the different imaging techniques were compared. For all of the 26 patients with metastases in the cervical spine the correct diagnosis was found with MR imaging and CT. Both modalities also revealed paravertebral tumour growth, MR (n = 8) more than CT (n = 3). The sensitivity of skeletal scintigraphy in detecting metastases in the cervical spine was rather low, but as these examinations cover the whole body they are still convenient screening procedures, and combined with conventional radiography of selected areas are probably sufficient in many cases. Supplementary examinations with CT or MR would be valuable in patients with equivocal findings at screening for metastases or with clinical indications of metastases that remain unexplained after scintigraphy and radiography.

Adult↗

PubMed1993

Quantification of inhomogeneities in malignancy grading of non-Hodgkin lymphoma with MR imaging.

In a previous study of 50 patients with non-Hodgkin lymphoma (NHL) it was shown that the inhomogeneous appearance of a tumor at MR imaging strongly indicated a high malignancy grade. In this study of 33 patients with NHL, the administration of an i.v. contrast medium, Gadolinium-DTPA, improved the subjective detectability of the inhomogeneities. A method of quantifying the degree of inhomogeneity in the tumors (inhomogeneity index, IH-index) was developed and tested. The mean value of IH-index in the T2-weighted image before contrast medium administration, and of the T1-weighted image after contrast medium administration, as well as the IH-index value in the T2-weighted image before contrast medium administration alone, was able to discriminate well between low- and high-grade NHL. This method of quantifying the degree of inhomogeneity in tumors improved sensitivity in detecting high-grade NHL.

Adult↗

PubMed1992

MRI of pituitary macroadenomas with reference to hormonal activity.

In 115 patients with pituitary macroadenomas, the findings on mid-field MRI were correlated with the hormonal activity of the tumours. Adenomas secreting growth hormone (GH), prolactin (PRL) and clinically nonsecretory adenomas were studied. Tumour size, invasiveness and signal intensity patterns were recorded. Relaxation times and ratios of signal intensity and proton density (relative to the corpus callosum) were analysed in areas of apparently solid tissue in a subgroup of 59 previously untreated patients. Invasiveness was more common in PRL- and GH-secreting adenomas than in the nonsecreting ones. Diffuse invasion of the base of the skull was most common in prolactinomas, and associated with a lower frequency of suprasellar tumour extension. In prolactinomas, a correlation was found between the maximum serum PRL level and tumour size. Haemorrhagic, cystic or necrotic areas were less common in GH-secreting tumours than in the other types. Haemorrhage was more common in prolactinomas than in nonsecreting tumours. MR parameters were similar in prolactinomas and nonsecreting adenomas, but indicated a smaller amount of water in GH-secreting tumours.

Adenoma↗

PubMed1992

MR imaging of acute myocardial infarction in pigs using Gd-DTPA-labeled dextran.

Myocardial infarctions were induced in 12 pigs. In 6 pigs, dextran-(Gd-DTPA)15 (approximately 0.1 mmol Gd/kg b.w.) was injected i.v. 4 to 4.5 hours after coronary artery occlusion. ECG gated MR images were obtained repeatedly before (n = 4) and after (n = 6) contrast medium injection. Relaxation times in blood samples were measured repeatedly. The animals were sacrificed 2 hours after contrast medium administration. The hearts were excised, reexamined in the MR equipment and stained with triphenyltetrazolium chloride (TTC) in order to define areas of infarction. The remaining 6 pigs were sacrificed 6 hours after occlusion without administration of contrast medium. These hearts were only imaged ex vivo. In vivo, the infarctions could not be identified with or without dextran-(Gd-DTPA)15. Ex vivo, without contrast medium, the infarctions had an increased signal intensity, most pronounced in the T2-weighted images. Dextran-(Gd-DTPA)15 caused a prolonged, pronounced shortening of T1 and T2 in blood samples. The infarct demarcation improved in the T1-weighted images after injection of dextran-(Gd-DTPA)15, due to a moderate enhancement in normal myocardium and a stronger enhancement at the periphery of the infarctions, while the central parts of the infarctions were only weakly enhanced.

Animals↗

PubMed1992

Nonresectable adenocarcinoma of the rectum assessed by MR imaging before and after chemotherapy and irradiation.

Thirty-four patients with nonresectable adenocarcinoma of the rectum, defined as tumor fixation at digital examination, were examined with MR. All 34 patients had, according to MR imaging, perirectal tumor growth. In 23 (68%) of the patients, the tumor has reached an adjacent organ. Eight of these patients had disturbances of the MR characteristics in the adjacent organ which proved to be due to overgrowth, i.e., to tumor invasion into these structures. In the remaining 15 patients, without disturbed MR characteristics, 7 had tumor overgrowth at laparotomy. When there was a visible space between the tumor and adjacent organs, there was no sign of tumor overgrowth at laparotomy, except in one case. In 24 patients, examined both before and after combined irradiation and drug therapy, tumor regression was registered after treatment. MR imaging seems to be useful in the assessment of resectability and to evaluate preoperative anticancer treatment in patients with nonresectable rectal carcinoma.

Adenocarcinoma↗

PubMed1992

MR imaging with histopathological correlation in vertebral metastases of breast cancer.

In 5 patients with advanced breast cancer and spinal metastases MR imaging of the spine was performed before and/or after death. T1-, proton density-, and T2-weighted and "phase contrast" images were obtained in the sagittal plane. Autopsies included histopathologic examination of whole sagittal sections of the vertebral body. The relative signal intensities on the different MR sequences of various tissues identified histologically were evaluated. "Phase contrast" images combined with T1-weighted images were highly sensitive in detecting metastases. All metastatic tumours over 3 mm in size were found with MR imaging. Vertebrae containing connective tissue and reactive bone marrow had an MR appearance similar to that of metastases even though no metastases were found histopathologically.

Adult↗

PubMed1991

Disc degeneration and associated abnormalities of the spine in elite gymnasts. A magnetic resonance imaging study.

The thoracolumbar spine was examined by magnetic resonance imaging (MRI) and the history of back pain was analyzed in 24 male elite gymnasts (age range, 19-29 years) and in 16 male nonathletes (age range, 23-36 years). Disc degeneration, defined as reduced disc signal intensity, was significantly more common in athletes (75%) than in nonathletes (31%). The gymnasts also had a higher incidence of other abnormalities of the thoracolumbar spine, and there was a significant correlation between reduced disc signal intensity and the other abnormalities among the gymnasts. There were also significant correlations between back pain and reduced disc signal intensity and abnormal vertebral configuration when the gymnasts run a high risk of developing severe abnormalities of the thoracolumbar spine, and they often have a history of back pain.

Adult↗

PubMed1991

Magnetic resonance imaging in idiopathic hemochromatosis.

The therapeutic management of patients with idiopathic hemochromatosis (IH) requires an accurate estimate of hepatic iron overload in order to prevent tissue fibrosis and organ failure. Magnetic resonance imaging (MRI) was used to estimate liver iron overload in 5 patients with IH and in 8 normal controls. Signal intensity ratio between liver and subcutaneous fat in T1-, proton- and T2-weighted images was significantly lower in IH when compared with normal controls, and increased gradually during treatment by phlebotomy. Mean serum ferritin at diagnosis was 755 micrograms/l (range: 648-900) in IH and 85 micrograms/l (range: 19-232) in normal controls. A high correlation (r = -0.93) was present between liver signal intensity ratio and serum ferritin; both changed in parallel during removal of iron by phlebotomy. MRI may provide a safe and accurate method of detecting iron overload in the precirrhotic phase of IH, obviating the need for liver biopsy. It may also be used to monitor treatment.

Adult↗

PubMed1991

1991 Volvo Award in clinical sciences. Smoking and lumbar intervertebral disc degeneration: an MRI study of identical twins.

The primary objective of this study was to determine whether disc degeneration, as assessed through magnetic resonance imaging, is greater in smokers than in nonsmokers. To control for the maximum number of potentially confounding variables, pairs of identical twins highly discordant for cigarette smoking were selected as study subjects. Data analyses revealed 18% greater mean disc degeneration scores in the lumbar spines of smokers as compared with nonsmokers. The effect was present across the entire lumbar spine, implicating a mechanism acting systemically. This investigation demonstrates the efficiency of using carefully selected controls in studying conditions of multifactorial etiology, such as disc degeneration.

Awards and Prizes↗

PubMed1991

Superparamagnetic particles as oral contrast medium in MR imaging of malignant lymphoma.

Non-biodegradable superparamagnetic particles, in plain and viscous aqueous suspensions, were used as an oral contrast medium in 34 patients with known or suspected malignant lymphoma. The contrast effect, the occurrence of artifacts, and the distribution were evaluated in the plain and the viscous aqueous suspensions, and the diagnostic information received from abdominal MR examinations performed without bowel contrast medium was compared with that of post-contrast examinations. Magnetic particles in the concentration of 0.5 g/l displayed a good contrast effect at 0.5 T, and helped in differentiating the intestine from adjacent tissues, resulting in increased diagnostic information in abdominal MR imaging. In the patients given the viscous aqueous suspension the occurrence of artifacts caused by the magnetic particles decreased considerably, and the distribution was homogeneous and improved compared with that in patients given the plain aqueous suspension.

Abdomen↗