Trade-off between pulse rate and radiation dose during modified barium swallow examination: what is the reality?

AIM: To evaluate the effect of modification of dose mode and frame rate on patient radiation dose during modified barium swallow (MBS) examinations. MATERIALS AND METHODS: A retrospective review was undertaken of consecutive MBS examinations performed over 6 months in the inpatient setting. Patients were divided into two cohorts: pre-implementation of the MBS Impairment Profile (MBSImP; low rate, normal dose) and post-implementation (high rate, low dose). Prior to implementation, pulse rate and dose testing were performed on multiple phantoms. RESULTS: Four hundred and forty-nine patients were included in the pre-implementation cohort and 378 in the post-implementation cohort. Phantom dose testing demonstrated no significant difference in dose on either phantom between low rate/normal dose and high rate/low dose modes. Prior to MBS standardisation, the mean radiation dose was 5.86 (±4.35) mGy. Following standardisation, the mean radiation dose was 4.72 (±3.77) mGy (p<0.0001). The mean fluoroscopy time for MBS prior to standardisation was 83.8 (±44.4) seconds and the mean fluoroscopy time for MBS after standardisation was 82.3 (±39.8) seconds (p=0.62). The dose rate for MBS prior to standardisation was 4.35 (±2.42) and the dose rate for MBS after standardisation was 3.55 (±2.41) mGy/s (p<0.0001). CONCLUSION: Adjustments made to lower the dose mode and the increase in fluoroscopy frame rate decreased the patient radiation dose and did not increase fluoroscopy time.

Diffusion-weighted MRI as a screening tool for hepatocellular carcinoma in cirrhotic livers: correlation with explant data-a pilot study.

OBJECTIVE: The purpose of this study was to compare the sensitivity and specificity of diffusion-weighted liver MRI alone with complete, multiphasic gadoteridol-enhanced MRI for the detection of hepatocellular carcinoma in cirrhotic patients before liver transplant. MATERIALS AND METHODS: This single institution retrospective study was performed after IRB approval and was HIPAA compliant. MRI scans of 37 patients who underwent liver transplant were evaluated and findings correlated with liver explant (36) or biopsy (1). All MRI scans were obtained within six months of explant. MRI from 17 patients with liver lesions by report at imaging subsequently proven to be HCC at pathology and 20 controls without liver lesions by imaging and pathology were reviewed in random order on the radiology PACS by three independent readers blinded to the MRI reports and pathology reports in two separate sittings. First, only the diffusion-weighted images (DWI) were interpreted. Second, the complete multiphasic MRI exam with DWI was reviewed. A consensus read was obtained by two separate radiologists who had access to the patients' explant data in order to map lesions. Reader-specific and pooled classification was assessed using sensitivity, specificity, positive predictive value, and negative predictive values and corresponding 95% confidence intervals (CI) for both DWI and complete MRI examination readings compared to pathology. McNemar's test and Kappa coefficient were used to assess differences (agreement) in DWI and complete examination readings. RESULTS: A total of 37 patients have been studied (25M 12F age range 21-70). Averaged results of the three independent readers demonstrated a sensitivity of 78% (95% CI 65-89%) and specificity of 88% (95% CI 77-95%) for DWI alone for detection of liver lesions, with a positive predictive value of 85% (95% CI 72-94%) and a negative predictive value of 83% (95% CI 71-91%). Review of the complete MRI exam showed a sensitivity of 90% (95% CI 76-97%) and a specificity of 82% (95% CI 66-92%) with a positive predictive value of 83% (95% CI 69-93%) and a negative predictive value of 89% (95% CI 74-97%). McNemar's agreement test revealed no significant difference between the DWI and complete multiphasic interpretations (p = 0.3458), with simple Kappa coefficient of 0.6716 (95% CI 0.5332-0.8110). Lesions identified on DWI ranged in size from 1.5 to 5 cm. Detection of lesions was decreased in the presence of artifact from motion, large ascites, and technical issues. CONCLUSION: Diffusion-weighted MRI has NPV and PPV comparable to complete multiphasic MRI examination for liver lesion detection in cirrhotic patients and may have a role in screening.

Treatment of locally advanced cervical cancer with concurrent radiation and intra-arterial chemotherapy.

The purpose of this study was to determine the maximum tolerated dose (MTD) and feasibility of treatment with sequential intra-arterial FUDR and cisplatin administered with concurrent whole pelvis radiation (XRT) to women with advanced cervical cancer. Sixteen patients with squamous carcinoma of the cervix were prospectively treated in a Phase I study. All tumors were stages IIb, IIIb, or IVa with diameters of > or = 7 cm. Patients underwent surgical staging with pelvic and paraortic lymphadenectomy with placement of bilateral intra-arterial catheters in the anterior division of the internal iliac arteries. The catheters terminated in separate subcutaneous ports. No patient had metastasis in the high common iliac or paraortic nodes. Patients received a planned course of 40-50 Gy whole pelvis XRT followed by indicated brachytherapy. During the first 2 weeks of whole pelvis XRT, patients received a 1-hr infusion of FUDR and during the second 2 weeks a 1-hr infusion of cisplatin, each delivered daily by external pump with the daily whole pelviS XRT fraction. Additional cisplatin was infused during brachytherapy. Five dose levels ranging from 6.5 to 27 mg/m2 daily for FUDR and from 2 to 8 mg/m2 daily for cisplatin were used. The MTD of FUDR and CDDP was dose level 4 (22.5 and 6.75 mg/m2, respectively). Dose-limiting toxicity was grade 3/4 nausea seen in three of four patients at dose level 5. No patient had neuro- or ototoxicity. There was no grade 4 myelosuppression. Eight patients had a complete response, and six had a partial response. Disease progressed in two. Mean follow-up was 22.4 months. At this writing, 10 patients had no evidence of disease, 2 were alive with disease, and 4 had died of disease. Median survival has not been reached. This is a well-tolerated regimen with significant activity that warrants further investigation at dose level 4.