Dimiter Tscholakoff

Duplex Doppler sonography in renal parenchymal disease. Histopathologic correlation.

To evaluate the histopathologic changes influencing Doppler measurements of the resistive index (RI) in renal arteries in renal parenchymal diseases, 68 kidneys in 34 consecutive patients with various forms of renal parenchymal diseases were studied by duplex Doppler ultrasound (duplex US) immediately before percutaneous renal biopsy. The RI, renal length, and renal cortical echogenicity were correlated with the amount of glomerular, interstitial, and vascular changes graded on a scale from 0 to 100. The renal vascular resistance and therefore the RI are significantly correlated with the prevalence of arteriolosclerosis, glomerular sclerosis, arteriosclerosis, edema, and focal interstitial fibrosis. There was no significant difference of the RI in five groups of different renal parenchymal diseases. Of 34 patients, 24 presented with an RI less than 0.7, which was thought to be within the normal range so far. Additionally, the RI increases as the patients age increases, due to higher incidence of arteriosclerosis. Of our patients, 44% presented with normal cortical echogenicity. Quantitative duplex US using the RI does not reliably distinguish different types of renal medical disorders.

MAGNETIC RESONANCE IMAGING OF THE SPINE IN MULTIPLE MYELOMA

The lower thoracic and lumbar spine of patients with multiple myeloma was examined by magnetic resonance imaging (MRI), plain radiography, and bone scintigraphy. Three independent investigators evaluated the power of these diagnostic methods to detect bone lesions in 192 vertebrae from 18 patients and in 60 vertebrae from 7 controls. 41 foci with abnormal signal intensity were detected by MRI; X-ray films showed osteolytic lesions in 4 vertebral bodies; and bone scanning was positive in 2 cases. The superiority of MRI in detecting myeloma-associated focal bone lesions was statistically significant, and in one case the lesions were confirmed at necropsy. Deviations in shape and height of vertebral bodies were slightly more easily visible on radiographs. Early detection of imminent medullary compressions in 2 patients led to successful radiotherapy before symptoms appeared.

Magnetic resonance imaging of the lower vertebral column in patients with multiple myeloma.

Eighteen patients with multiple myeloma (clinical stages 1-3) and a control group of 21 persons underwent magnetic resonance imaging (MRI) studies of the lower thoracic and lumbar spine. This was done to determine the potential benefit of MRI in addition to conventional radiographs, tomograms, computed tomography and nuclear scans. In addition to focal fatty replacement of normal hematopoietic marrow, which presented as focal hyperintense lesions on T1-weighted images (T1-WI) and on T2-weighted images (T2-WI), two types of myelomatous lesions were found: (1) focal areas with reduced signal intensity when compared with normal bone marrow on T1-WI and enhanced signal intensity on T2-WI, mainly found in untreated myelomas; and (2) focal areas of decreased signal intensity on T1-WI and on T2-WI, which were predominantly detected after previous radiation therapy. MRI surpassed conventional radiography in detecting abnormal focal marrow infiltration in 41 of 247 vertebrae. Radiographs identified only 11 of the 41 as pathologic, based on shape and structure of the vertebral bodies; however, 15 other collapsed vertebrae showed no signal abnormalities of the marrow on MR images. Discrimination of normals and abnormals by statistical analysis of intensity measurements of the bone marrow was not possible.

Comparison of MR angiography versus digital subtraction angiography as a basis for planning treatment of lower limb occlusive disease.

Purpose: To compare contrast-enhanced moving-bed magnetic resonance angiography (MRA) with digital subtraction angiography (DSA) for the ability to provide adequate information on which to construct a therapeutic strategy in patients suffering from peripheral arterial occlusive disease (PAOD). Methods: A prospective study was conducted involving 48 consecutive patients (25 men; mean age 65.7±10.2 years) with PAOD who underwent MRA and DSA of the peripheral arteries on 2 consecutive days. Every leg was divided into 3 anatomical regions (suprainguinal, femoropopliteal, calf), and the sensitivity and specificity for the detection of significant (>70%) lesions, as well as the interobserver variability, were calculated. The potential differences in the therapeutic strategy based on the results of both modalities were evaluated. Results: The MRA and DSA studies in the 48 study patients produced 864 arterial segments for interpretation. The sensitivity of MRA for the detection of significant lesions was 94.7% for the suprainguinal, 89.5% for the femoropopliteal, and 91.3% for the calf arteries. Corresponding specificity was 98.1%, 96.2% and 93.4%, respectively. The interobserver correlation for the detection of significant lesions by MRA and DSA was excellent (κ>0.8) for all 3 segments, with slightly superior values for MRA. MRA and DSA agreed in the grading of 821 (95.0%) segments. In 8 (16.7%) patients, MRA suggested an additional intervention, and in 3 (6.3%) patients, additional DSA was necessary for the final diagnosis. Conclusions: The accuracy of MRA for the detection of significant lesions is comparable to DSA. Basing the therapeutic strategy solely on the results of MRA can reduce the number of DSAs by three quarters, but at the risk of incurring lesion overestimation in ∼17%.

Duplex Doppler sonography of celiac trunk and superior mesenteric artery : comparison with intra-arterial angiography

DDS was compared to intra‐arterial angiography for the diagnosis of significant (> 50%) stenoses of the celiac trunk and the SMA in 38 consecutive patients referred for angiographic evaluation of peripheral arterial occlusive disease. Celiac trunk occlusion was correctly identified by DDS in three of three patients. In patients with significant celiac trunk stenoses, mean peak systolic velocity was 246 (+/‐ 154) cm/sec and differed significantly (P < 0.05) from the peak systolic velocity (101 +/‐ 22 cm/sec) of 22 patients with no angiographic evidence of significant stenosis. Five false‐negative DDS examinations in patients with > 50% celiac trunk stenoses were noted. Using a peak systolic velocity of > 160 cm/sec (mean value in normal vessels plus 3 standard deviations) to diagnose > 50% celiac trunk stenosis, sensitivity of DDS was 57% and specificity was 100%. However, considering celiac trunk stenoses and occlusions as a single group, the sensitivity rate of DDS in diagnosing significant stenosis and occlusion of celiac trunk was 70%.

Contrast-enhanced MRI for the staging of bronchogenic carcinoma: comparison with CT and histopathologic staging--preliminary results.

Nineteen patients with potentially operable bronchial carcinoma were included in a prospective study to assess the staging capabilities of plain and contrast-enhanced magnetic resonance imaging (MRI) in comparison with computed tomography (CT) and to compare the results to post-operative histopathological staging (HS). The evaluation focused on the following T-staging criteria: (i) direct invasion of the pleura; (ii) neoplastic invasion of the mediastinum; (iii) differentiation of the primary tumour from alterations of the surrounding lung parenchyma such as inflammation or atelectasis; and (iv) intrathoracic lymph node involvement by tumour. MRI and CT produced similar results for pleural invasion (sensitivity of 0.4 and 0.75 respectively and a specificity of 0.86 and 0.93 respectively). Mediastinal invasion was overdiagnosed in four patients (no false negatives), whereas CT had only one false positive result (two false negatives). Our results showed CT to be superior to MRI for the preoperative evaluation of patients suffering from bronchogenic carcinoma.

Course of platelet counts in cirrhotic patients after implantation of a transjugular intrahepatic portosystemic shunt - a prospective, controlled study

BACKGROUND/AIMS The pathogenesis of thrombocytopenia associated with advanced liver disease is still controversial. To study the impact of portal decompression on this hematologic complication, we conducted a prospective, controlled study to compare the course of platelet counts in patients after implantation of a transjugular intrahepatic portosystemic shunt (TIPS) with matched controls without shunts. METHODS Fifty-five TIPS patients and 110 controls matched for age, sex, Child-Pugh class, etiology of liver disease and baseline platelet count were included, and followed for 1 year. Follow-up visits were scheduled after 1 month, after 3 months, and at 3-month intervals thereafter. RESULTS Nonparametric Mann-Whitney U-tests revealed significantly higher platelet counts for TIPS patients as compared to controls from the 1st through the 12th month (p<0.01). During the study period, the median platelet count of TIPS patients increased by 19.7%, from 104.0/nl (IR: 68.0) to 124.5/nl (IR: 41.0). In contrast, during the same period the median platelet count of controls decreased by 17.1%, from 102.5/nl (IR: 66.0) to 85.0/nl (IR: 67.5). In the group of cases with baseline platelet counts < or =100/nl, platelet counts had increased by at least 25% at month 12 in 65% of TIPS patients, but in only 5% of controls (p<0.001). However, normalization of platelet counts, i.e. > or =150/nl, was not achieved in any case. Neither the portosystemic pressure gradient after TIPS implantation, nor the percentage of portosystemic pressure gradient reduction during the procedure was predictive of platelet response. CONCLUSIONS TIPS implantation increases platelet counts significantly. However, portal hypertension is clearly not the only mechanism contributing to thrombocytopenia in advanced liver disease.

Comparison of Duplex sonography and color Doppler imaging in renal allograft evaluation: a prospective study

A prospective study compared the diagnostic capability of quantitative Duplex sonography (DS) and color Doppler imaging (CDI) in 49 consecutive patients with 50 renal allografts. Sixty five DS examinations and 65 CDI examinations were performed by two independent investigators on two different machines on the same day. The resistive index (RI) was calculated and the color flow of renal arteries was observed up to the arcuate arteries. There was good correlation of RI values obtained by DS and CDI at all vascular sites. Thirty one allografts were functioning stably and 19 were in a state of dysfunction, defined by histology (n = 17). Forty allografts presented with a RI less than 0.9 and normal color flow. All five allografts with a pathologic RI greater than or equal to 0.9 showed abnormal color flow (missing flow in arcuate and/or interlobar arteries). Five allografts had a RI less than 0.9 but abnormal color flow, possibly due to atrial fibrillation, hypertension, heart failure or a combination of these. A normal color flow pattern excludes severe vascular compromise to the allograft. In addition, CDI revealed three biopsy-related vascular lesions; two of them had been missed by DS.

Clinical outcome two years after implantation of a transjugular intrahepatic portosystemic shunt for recurrent variceal bleeding

Objective: Implantation of a transjugular intrahepatic portosystemic shunt (TIPS) is a relatively new therapy for variceal bleeding. The aim of this study was to assess clinical course 2 years after TIPS procedure. Design: The study was designed as a prospective, uncontrolled cohort study. Methods: Forty‐six patients who underwent successful TIPS implantation were followed prospectively by clinical examinations, duplex sonography and portal venography. Mean follow‐up in surviving patients was 24.1 ±9.0 months. Results: The cumulative rate of survival was 80.4% at 1 year and 70.2% at 2 years. The cumulative rebleeding rate was 12.4% at 1 year and 21.3% at 2 years. The mortality rate of episodes of variceal rebleeding was 22.2%. Variceal rebleeding was associated with shunt abnormalities, and successful shunt revision resulted in control of the bleeding. The cumulative incidence of shunt stenosis or occlusion was 41.2% at 1 year and 54.9% at 2 years. Of those patients without shunt abnormalities after 1 year, 23.3% developed shunt stenosis or occlusion during the second year after TIPS procedure. Shunt revision was successful in 96.6% of cases. Secondary patency rate was 88.1% after 2 years. Conclusion: Successful TIPS implantation results in a low rate of morbidity and mortality from variceal rebleeding over 2 years. TIPS creation in combination with careful follow‐up examinations represents an effective long‐term treatment of recurrent variceal bleeding. Even in patients in whom no shunt abnormality is detected during the first year, routine duplex follow‐up examinations should be continued at 3‐month intervals.

Contrast MRI in multiple endocrine neoplasia type 1 (MEN) associated with renal cell carcinoma

The radiologic work-up of a patient with multiple endocrine neoplasia type 1 (MEN 1) syndrome and multiple endocrine nodules, with coincidental renal cell carcinoma, is described. Parathyroid adenoma was differentiated from multiple thyroid nodules by gadolinium-enhanced MRI. Adrenal enlargement due to a nonfunctioning adenoma and a renal cell carcinoma next to a simple renal cortical cyst were identified by typical signal intensities on T1- (pre- and post-Gd-DPTA) and T2-weighted images. Insulinoma was visualized only retrospectively.