Relationship between duration of pain and secondary signs of obstruction of the urinary tract on unenhanced helical CT

OBJECTIVE

The objective of this study was to investigate the relationship between duration of flank pain and the frequency of secondary signs of ureteral obstruction on unenhanced helical CT.

SUBJECTS AND METHODS

The duration of flank pain was prospectively determined in 227 consecutive patients diagnosed with acute ureterolithiasis on unenhanced helical CT. These CT studies were evaluated for the presence or absence of perinephric stranding, ureteral dilatation, perinephric fluid, collecting system dilatation, periureteral stranding, and nephromegaly. The frequency of each sign was determined as a function of the duration of pain.

RESULTS

The frequency of moderate or severe perinephric stranding increased from 5% at 1--2 hr to 51% at 7--8 hr (p < 0.001); ureteral dilatation increased from 84% at 1--2 hr to 97% at more than 8 hr (p < 0.03); moderate or severe perinephric fluid increased from 0% at 1--2 hr to 22% at 3--4 hr (p < 0.03); collecting system dilatation increased from 68% at 1--2 hr to 89% at 7-8 hr (p < 0.03); periureteral stranding increased from 35% at 1--2 hr to 76% at 7--8 hr (p < 0.004); and nephromegaly increased from 40% at 1--2 hr to 54% at 7--8 hr (p < 0.36).

CONCLUSION

All CT secondary signs of ureteral obstruction except nephromegaly showed a significant increase in frequency as duration of flank pain increased. This observation may explain why the CT studies of some patients with acute ureterolithiasis show negative findings for some or all CT secondary signs of obstruction. Therefore, knowledge of the duration of pain is important when interpreting unenhanced CT studies in patients with acute ureterolithiasis.

Preoperative use of 3D volume rendering to demonstrate renal tumors and renal anatomy

With increased use of computed tomography (CT) and abdominal ultrasonography, the indications for nephron-sparing surgery are also increasing. Triphasic helical CT and three-dimensional (3D) volume rendering can be combined into a single noninvasive test to delineate renal tumors and normal and complex renal anatomy prior to nephron-sparing surgery. This combination technique has proved accurate and very useful for both preoperative and intraoperative planning by demonstrating renal position, tumor location and depth of tumor extension into the kidney, relationship of the tumor to the collecting system, and renal vascular anatomy. Knowledge of the position of the kidney relative to the lower rib cage, iliac crest, and spine helps in planning the initial surgical incision. By depicting tumor location and depth of extension, helical CT with 3D volume rendering helps ensure complete tumor excision and conservation of adjacent normal renal parenchyma. Depiction of the relationship of the tumor to the collecting system helps anticipate further tumor extension and minimize postoperative complications. Identification of normal renal vasculature and anatomic variants can help minimize ischemic injury and intraoperative bleeding. Radiologists should be familiar with current indications for nephron-sparing surgery and understand what information is required prior to surgery.

Imaging appearances of Sister Mary Joseph nodule

Sister Mary Joseph nodules are metastatic deposits in the periumbilical area. The purpose of this review is to demonstrate umbilical anatomy, discuss modes of metastatic spread, the various imaging appearances and their relevance to the radiologist.

Triphasic helical CT of the kidneys: contribution of vascular phase scanning in patients before urologic surgery

OBJECTIVE

The purpose of this study was to evaluate the potential benefits of performing vascular phase scanning of the kidneys in addition to unenhanced and parenchymal phase contrast-enhanced CT in patients being examined for urologic surgery.

MATERIALS AND METHODS

Parenchymal and vascular phase images from triphasic renal helical CT of 50 patients were sequentially evaluated in a randomized, retrospective fashion by two independent observers. The number of renal arteries and veins and the presence of vein or collecting system anomalies were recorded for each scan phase along with a subjective 10-point-scale score of the visibility of the vasculature and collecting system. Correlation of these findings was made with surgical or angiographic findings in 67 of the 87 kidneys and was made by consensus review in the remaining 20 kidneys.

RESULTS

Accessory renal arteries were seen significantly more often (p < .05, chi-square test) on the vascular phase scans. The subjective scores for the visibility of the renal arteries and renal veins were significantly higher on the vascular phase scans (p < .0001, Wilcoxon's rank sum test). The subjective scores for the visibility of the filling of the collecting system and renal pelvis were significantly higher for the parenchymal phase scans, despite the use of a small contrast bolus before each scan (p < .0001, Wilcoxon's rank sum test). CONCLUSION; Triphasic renal CT better reveals the artery and vein anatomy of the kidney than does parenchymal phase imaging only. Triphasic helical CT is indicated in patients undergoing planning for urologic surgery when vascular anatomy is clinically important.

3-dimensional volume rendered computerized tomography for preoperative evaluation and intraoperative treatment of patients undergoing nephron sparing surgery

Background:

Live donor nephrectomy has gained popularity on account of the laparoscopic technique, to overcome a small donor pool. Laparoscopic donor nephrectomy requires a precise study of the vascular and morphological renal anatomy, as laparoscopy is technically challenging due to the limited field of vision. In-depth knowledge of the renal anatomy before a laparoscopic procedure is essential for a successful transplant. The left kidney is preferred over the right even in cases of multiple vessels because of the long renal vein, which requires precise preoperative vascular mapping. Helical computerized tomography (CT) angiography, with its axial, coronal, and 3D reconstruction, gives a better understanding of renal anatomy. There are instances where the helical CT findings are misleading and less informative in a small number of cases. This study highlights a case study of the helical CT findings compared with the intraoperative findings of 200 live donors, who underwent laparoscopic donor nephrectomy, and the renal anatomy has been understood at the same time.

Aims:

1. To compare the helical CT findings on the operated side with the intraoperative findings. 2. To analyze the CT findings

Materials and Methods:

Two hundred cases of laparoscopic transperitoneal donor nephrectomy were included in this study.

Statistical Method Used:

Chi square test was the statistical test used to compare the findings between CT and the intraoperative data.

Results:

The axial, coronal, and 3D images of the CT findings were on par with the intraoperative findings in most of the cases. Incidental findings help in the better planning of surgery. Multiple vessels on the left side are preferred over the right sided normal anatomy; with not much technical difficulty with the aid of a helical CT. Male donors had more incidences of multiple vessels, gonadal vein, Retroaortic Renal Vein (RARV), lumbar vein, and duplication of ureter, compared to females. Furthermore, these variations are more in the left side donors. Ninety-two percent of the cases in this study are left-sided donors. The helical CT finding shows that renal vein variations are more on the right side.

Conclusions:

Helical CT is important in delineating the arterial, venous, and ureteral anatomy and can show the important incidental findings. Left renal donors and males have more variations in their renal anatomy. Technically challenging laparoscopic nephrectomy on the multiple-vessel-side donor is possible with the aid of helical CT. The importance of the CT in evaluating donor renal anatomy for a technically challenging laparoscopic donor nephrectomy is commendable.

3-dimensional volume rendered computerized tomography for preoperative evaluation and intraoperative treatment of patients undergoing nephron sparing surgery

PURPOSE

Computerized tomography (CT) is the diagnostic and staging modality of choice for renal neoplasms. Existing imaging modalities are limited by a 2-dimensional (D) format. Recent advances in computer technology now allow the production of high quality 3-D images from helical CT. Nephron sparing surgery requires a detailed understanding of renal anatomy. Preoperative evaluation must delineate the relationship of the tumor to adjacent normal structures and demonstrate the vascular supply to the tumor for the surgeon to conserve as much normal parenchyma as possible. We propose that helical CT combined with 3-D volume rendering provides all of the information required for preoperative evaluation and intraoperative management of nephron sparing surgery cases. We prospectively evaluated the role of 3-D volume rendering CT in 60 patients undergoing nephron sparing surgery for renal cell carcinoma at the Cleveland Clinic Foundation.

MATERIALS AND METHODS

Triphasic spiral CT was performed preoperatively in 60 consecutive patients undergoing nephron sparing surgery for renal neoplasms. A 3 to 5-minute videotape was prepared using volume rendering software which demonstrated the position of the kidney, location and depth of extension of the tumor(s), renal artery(ies) and vein(s), and relationship of the tumor to the collecting system. These videotapes were viewed by a radiologist and urologist in the operating room at surgery, and immediately correlated with surgical findings. Corresponding renal arteriograms of 19 patients were retrospectively compared to 3-D volume rendering CT and operative findings.

RESULTS

A total of 97 renal masses were identified in 60 cases evaluated with 3-D volume rendering CT before nephron sparing surgery. There were no complications related to the 3-D protocol and 3-D rendering was successful in all patients. The number and location of lesions identified by 3-D volume rendering CT were accurate in all cases, while enhancement and diagnostic characteristics were consistent with pathological findings in 95 of 97 tumors (98%). Of 77 renal arteries identified at surgery 74 were detected by 3-D volume rendering CT (96%). Helical CT missed 3 small accessory arteries, including 1 in a cross fused ectopic kidney. All major venous branches and anomalies were identified, including 3 circumaortic left renal veins. Of 69 renal veins identified at surgery 64 were detected by 3-D volume rendering CT (93%). All 5 renal veins missed by CT were small, short, duplicated right branches of the main renal vein. Renal fusion and malrotation anomalies were correctly identified in all 4 patients.

CONCLUSIONS

The 3-D volume rendering CT accurately depicts the renal parenchymal and vascular anatomy in a format familiar to most surgeons. The data integrate essential information from angiography, venography, excretory urography and conventional 2-D CT into a single imaging modality, and can obviate the need for more invasive imaging. Additionally, the use of videotape in an intraoperative setting provides concise, accurate and immediate 3-D information to the surgeon, and it has become the preferred means of data display for these procedures at our center.