Yield of imaging and scintigraphy assessing biochemical failure in prostate cancer patients

A retrospective study was undertaken to determine the diagnostic yield of computed tomography (CT) and bone scan in patients with biochemical failure after definitive therapy for prostate cancer. The records of the Radiation Oncology Division were screened for patients presenting with prostate cancer between January 1, 1993, and December 31, 1996. Of 198 patients, 44 developed biochemical failure postoperatively (n = 24) or postradiotherapy (n = 20), and were not treated with hormones prior to restaging. Review was made of restaging studies performed at the time of biochemical failure. Postoperatively, 5% (1 of 20) of bone scans and 11% (2 of 18) of CT scans were positive. Postradiotherapy, 30% (6 of 20) of bone scans and 30% (3 of 10) of CT scans were positive. Our study showed that imaging studies are of low utility in the evaluation of patients with biochemical failure after definitive therapy of prostate cancer given that most patients begin hormonal therapy irrespective of the results of restaging studies. If salvage therapy is considered, imaging results may have a role in the decision-making process.

Acetabular stress fractures in military endurance athletes and recruits: incidence and MRI and scintigraphic findings

OBJECTIVE

To evaluate the incidence and the MRI and scintigraphic appearance of acetabular stress (fatigue) fractures in military endurance athletes and recruits.

DESIGN AND PATIENTS

One hundred and seventy-eight active duty military endurance trainees with a history of activity-related hip pain were evaluated by both MRI and bone scan over a 2-year period. Patients in the study ranged in age from 17 to 45 years. They had hip pain related to activity and had plain radiographs of the hip and pelvis that were interpreted as normal or equivocal. The study was originally designed to evaluate the MRI and scintigraphic appearance of femoral neck stress fractures. Patients had scintigraphy and a limited MRI examination (coronal imaging only) within 48 h of the bone scan. Twelve patients demonstrated imaging findings compatible with acetabular stress fractures.

RESULTS

Stress fractures are common in endurance athletes and in military populations; however, stress fracture of the acetabulum is uncommon. Twelve of 178 patients (6.7%) in our study had imaging findings consistent with acetabular stress fractures. Two patterns were identified. Seven of the 12 (58%) patients had acetabular roof stress fractures. In this group, two cases of bilateral acetabular roof stress fractures were identified, one with a synchronous tensile sided femoral neck stress fracture. The remaining five of 12 (42%) patients had anterior column stress fractures, rarely occurring in isolation, and almost always occurring with inferior pubic ramus stress fracture (4 of 5, or 80%). One case of bilateral anterior column stress fractures was identified without additional sites of injury.

CONCLUSIONS

Stress fractures are commonplace in military populations, especially endurance trainees. Acetabular stress fractures are rare and therefore unrecognized, but do occur and may be a cause for activity-related hip pain in a small percentage of military endurance athletes and recruits.

Frequency of coexistent disease at CT in patients with prostate carcinoma selected for definitive radiation therapy: is limited treatment-planning CT adequate?

PURPOSE

To document the frequency of clinically important coexistent disease depicted at contrast material-enhanced abdominal and pelvic computed tomography (CT) in patients undergoing definitive radiation therapy for prostate carcinoma, as such lesions might be missed at limited nonenhanced treatment-planning CT.

MATERIALS AND METHODS

Of 133 consecutive patients with prostate carcinoma who were referred to the radiation oncology division between January 1, 1994, and December 31, 1996, 77 underwent definitive radiation therapy that required either contrast-enhanced abdominal and pelvic CT (n = 67) or contrast-enhanced pelvic CT (n = 10). Results of these studies were reviewed and retrospectively categorized.

RESULTS

Forty-eight (62%) of the 77 patients had either negative studies or minor abnormalities that did not require further follow-up. Only two patients (3%) had major abnormalities that required intervention. Five patients (6%) had new findings of clinically important coexistent disease, but no intervention was required.

CONCLUSION

The incidence of clinically important coexistent disease in patients with prostate carcinoma who are referred for definitive radiation therapy is low. Therefore, contrast-enhanced abdominal and pelvic CT in addition to treatment-planning CT is of limited value.

Marrow MR signal abnormality associated with bilateral avulsive cortical irregularities in a gymnast

Abnormal marrow signal and marrow enhancement have not been described in association with benign avulsive cortical irregularity. We present the case of an 11-year-old gymnast with such findings that partially resolved over time. The marrow MR abnormalities are believed to represent an extension or spectrum of findings associated with avulsive cortical irregularity, and should not instantly suggest infection or malignancy, as has been previously indicated. Careful and close clinical and radiological follow-up is required to confirm its benign course.

Renal imaging with spiral CT scan: clinical applications

Spiral computed tomography (CT) is an imaging modality that utilizes the rapid acquisition of cross-sectional data that can be reconstructed in a number of useful ways. We briefly describe the technology of spiral CT and recent advancements that have made spiral CT feasible. The advantages over conventional CT and angiography are reviewed. Urologic clinical applications are discussed including: detection of a crossing vessel prior to endopyelotomy for ureteropelvic junction (UPJ) obstruction, evaluating renal vascular anomalies preoperatively, and assistance in preoperative planning prior to partial nephrectomy in benign and malignant disease. Spiral CT has numerous advantages over conventional CT and angiography, and will likely have a notable role in future renal imaging.

Resolution of abnormal MR signal intensity in patients with stress fractures of the femoral neck

OBJECTIVE

The purpose of this study was to describe the natural evolution of abnormal MR signal intensity after the diagnosis of a stress fracture of the femoral neck and to ascertain the time to resolution of that abnormal signal intensity.

SUBJECTS AND METHODS

Ten patients who had been previously diagnosed with stress fractures of the femoral neck after positive MR scans of the hip were examined with MR imaging at regular intervals. In each patient T1-weighted and short inversion time inversion recovery (STIR) sequences were obtained until the abnormally bright, diffuse MR signal intensity (representing edema) disappeared from the STIR images. Time to resolution was correlated with each patient's age and presence or absence of a fatigue line on MR imaging. Statistical analysis was done using Fisher's exact test.

RESULTS

Edema resolved in seven patients within 3 months of initial diagnosis, in two patients within 6 months, and in the remaining patient within 12 months. We found no statistically significant correlation between time to resolution and patient age or the presence of a fatigue line on MR imaging. Residual sclerosis occurred in five patients, all of whom had a fatigue line. Two of these patients developed bright T1 signal (fatty marrow conversion) around the area of sclerosis. In the remaining three patients, STIR images revealed a brightened fatigue line, which we presumed was caused by granulation tissue.

CONCLUSION

In this study, 90% of patients showed resolution of abnormal MR signal intensity on STIR imaging within 6 months of the initial diagnosis of stress fracture of the femoral neck. Such data may prove helpful in examining patients with recurrent symptoms who undergo repeated MR scanning. When an abnormally bright, diffuse MR signal intensity on STIR imaging is seen more than 6 months after an original injury, such abnormal signal intensity is likely to represent new injury.