Ureteral jets in healthy subjects and in patients with unilateral ureteral calculi: comparison with color Doppler US

Color Doppler ultrasound was used to image the ureteral jets in 17 healthy subjects and 26 patients with ureteral calculi proved with intravenous urography. In patients with ureteral calculi, three patterns of ureteral jets were seen: no detectable urine flow from the symptomatic side (12 patients), low-level continuous flow from the symptomatic side (four patients), and periodic ureteral jets on the symptomatic side that were not significantly different from ureteral jets of healthy subjects (10 patients). Of the 12 patients with high-grade obstruction on urograms, 11 had ureteral jets significantly different from those of healthy subjects (either no detectable ureteral jets or continuous low-level jets on the symptomatic side). Only three of the 11 patients with low-grade obstruction or nonobstructing stones had ureteral jets that were different from those of healthy subjects. It is concluded that analysis of ureteral jets with color Doppler can enable detection and qualitative determination of the degree of ureteral obstruction in many patients with unilateral ureteral calculi.     

Residual mediastinal masses in Hodgkin disease: prediction of size with MR imaging

Eighteen patients with mediastinal involvement of Hodgkin disease were examined with magnetic resonance (MR) imaging before and during therapy to find out if size of residual masses could be predicted from the MR characteristics of the tumor at diagnosis. After the first treatment, a significant decrease in T2 values and signal intensity ratios of tumor to fat and tumor to muscle was found in all patients. There was no significant change in T1 values. The relative decrease in tumor size correlated well with signal intensity ratios and poorly with T2 values of the original tumor. No correlation with T1 values was found. The authors conclude that size of the residual mass can be predicted from the initial size of the tumor and the signal intensity ratios at diagnosis. Since the degree of low signal intensity in the tumor before treatment probably reflects the amount of fibrotic tissue, these results support the hypothesis that residual masses after treatment are remnants of the fibrotic stroma of the original tumor.     

A New Multisensor Pacing System Using Stroke Volume, Respiratory Rate, Mixed Venous Oxygen Saturation, And Temperature, Right Atrial Pressure, Right Ventricular Pressure, And dP/dt

A new multisensor pacing device using respiratory rate (RR), stroke volume fSV), oxygen saturation (SO2), temperature (T), right atrial pressure (RAPJ, right ventricular pressure (RVPJ and right ventricular dP/dt, has been developed. It consists of a 7F multisensor catheter and an external pacing unit. It allows simultaneous recording of the input signals and the corresponding data can be compared among the different parameters under identical conditions. Furthermore, several parameters can be combined in such a way as to form a new combination better suitable for rate responsive pacing. The response of each parameter to exercise was studied in 12 healthy volunteers (mean age:28 years). Exercise testing was carried out using a bicycle ergometer, with workloads up to 200 W. The dynamic characteristics, response and sensitivity to changes of workloads of each parameter were analyzed and compared to one another. SO₂ proved to be a quick responding parameter (<10 sec) with higher sensitivity in the low exercise range (<75 WJ, T, on the other hand, responded slowly (>30 sec) to exercise changes and had the highest sensitivity in the exercise range beyond 75 W. RR displayed a slow response (>30 sec) and an adequate sensitivity was only found in the upper exercise range (>100 W). SV reacted rapidly to workload changes (<10 sec) but showed poor sensitivity at all exercise levels. RAP, RVP and dP/dt displayed quick responses and constantly good sensitivity throughout the workload range. Furthermore, respiratory rate was easily-derived from the RAP curve. Special algorithms were developed for each parameter so that pacing rate would reproduce sinus rate behavior. We found that SO₂ and all pressure parameter imitated sinus rate response quite well. When using parameter combinations, SO₂ and T proved to be superior. Five patients (mean age 68 years) with third degree AV-block were stimulated temporarily using this system. Compared to fixed rate stimulation [VVI 70], exercise performance improved, using SO₂ as the input parameter for rate response, by 25% to 50%.     

Posttransplant renal rejection: comparison of quantitative scintigraphy, US, and MR imaging

Accuracy of ultrasonography (US), quantitative scintigraphy, and magnetic resonance (MR) imaging in diagnosis of acute renal allograft rejection was studied in 46 patients who underwent renal biopsy. Thirty-three patients had acute rejection; six, cyclosporine nephrotoxicity, as shown by biopsy, clinical findings, and follow-up study; two, acute tubular necrosis; and five, normal biopsy findings and renal function. Accuracy in demonstrating rejection was 72% for US and 75% for scintigraphy, indicating no significant difference between the two. MR imaging was significantly more accurate, reaching a level of 98%. However, accuracy of MR in demonstrating acute tubular necrosis in a larger number of patients is not known, and its accuracy in indicating recurrent glomerulopathy or infectious disease has not been addressed. The definitive role of MR in evaluating posttransplant renal failure is currently not established, but because of its high sensitivity in detecting renal abnormality, MR can be used for cases when results of US or scintigraphy are equivocal or contradict clinical impressions or when biopsy cannot be performed for medical reasons.     

Puerperal ovarian vein thrombosis: evaluation with CT, US, and MR imaging

Five women suspected of having puerperal ovarian vein thrombosis (POVT) were examined with either computed tomography (CT) (five patients), ultrasonography (US) (three patients), magnetic resonance (MR) imaging (one patient), or a combination of these modalities. CT findings included tubular retroperitoneal mass (five patients), periuterine mass (four patients), enlarged uterus (four patients), fluid in the uterus (five patients), central ovarian vein thrombus (four patients), inferior vena cava thrombus (one patient), right hydroureter (one patient), and right ureteral compression (one patient). US findings were similar to CT findings except for an inability to demonstrate the right hydroureter and ureteral compression. MR imaging demonstrated the retroperitoneal mass and central ovarian vein thrombus. CT proved to be superior for the initial evaluation and subsequent diagnosis of POVT. US was useful for follow-up examinations, and MR imaging results confirmed a case of POVT that was suspected following CT.     

Timing and course of neonatal intracranial hemorrhage using real-time ultrasound

Knowledge of the timing and course of neonatal intracranial hemorrhage is essential in determining the etiology of hemorrhage, since the key to preventing neurologic damage in newborns is to define preventable causes and to treat the complications of hemorrhage. In an intensive study of 49 neonates delivered less than or equal to 32 weeks gestation, the initial hemorrhage typically occurred in the first three days of life, with 36% occurring on day 1, 32% on day 2, and 18% on day 3. Most of the major hemorrhages (Grades III and IV) occurred on day 1, although ventricular enlargement occurred at a variable time after the initial insult. By the sixth day, 91% of all intracranial hemorrhage had occurred.     

Neonatal aortic arch thrombosis

An infant presented shortly after birth with signs suggestive of aortic coarctation. Echocardiography revealed an extensive aortic arch thrombus, not amenable to surgery. Thrombolytic agents reduced thrombus size, enabling survival, but failed to prevent neurological damage secondary to cerebral embolisation.