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Masoom A Haider

Publications and source records attributed to Masoom A Haider.

At least 19 recordsLinked to original sources
PubMed2007

Correlations between dynamic contrast-enhanced magnetic resonance imaging-derived measures of tumor microvasculature and interstitial fluid pressure in patients with cervical cancer.

PURPOSE: To correlate permeability (rk(trans)), extracellular volume fraction (rv(e)), relative to muscle and initial area under the enhancement curve (IAUC(60m)) determined by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) with in vivo measurements of interstitial fluid pressure (IFP) in patients with cervical cancer. MATERIALS AND METHODS: DCE-MRI and IFP measurements were performed of cervical tumors of 32 patients prior to therapy. Median tumor rk(trans) and rv(e) were derived from a bidirectional two-compartment model using an input function derived from muscle. Median IAUC(60m) was defined as the integral of tumor enhancement in the first 60 seconds divided by the similar muscle enhancement integral. These parameters were correlated with the mean tumor IFP. RESULTS: There was a significant negative correlation between IAUC(60m) and IFP (r = -0.42, P = 0.016) and between rk(trans) and IFP (r = -0.47, P = 0.008). The was no significant correlation between IFP and rv(e). CONCLUSION: There is a moderate negative correlation between IAUC(60m), rk(trans), and IFP in cervical cancer. This suggests that these parameters may be of value in assessment of tumor behavior.

Adult↗
PubMed2006

Analysis of factors important for transurethral ultrasound prostate heating using MR temperature feedback.

The feasibility of using MR thermometry for temperature feedback to control a transurethral ultrasound heating applicator with planar transducers was investigated. The sensitivity of a temperature-based feedback algorithm to spatial (control point area, slice thickness, angular alignment) and non-spatial (imaging time, temperature uncertainty) parameters was evaluated through numerical simulations. The angular alignment of the control point with the ultrasound beam was an important parameter affecting the average spatial error in heat delivery. The other spatial parameters were less influential, thus providing an opportunity to reduce spatial resolution for increased SNR in the MR imaging. The update time was the most important non-spatial parameter determining the performance of the control algorithm. Combined non-spatial and spatial parameters achieved acceptable performance with a voxel size of 3 mm x 3 mm, a 10 mm slice thickness and a 5 s update time. Temperature uncertainty of up to 2 degrees C had little effect on the performance of the control algorithm but did reduce the average error slightly due to a systematic, noise-induced overestimation of the boundary temperature. These simulations imply that MR thermometry performed on clinical 1.5 T imaging systems is of sufficient quality for use as thermal feedback for conformal prostate thermal therapy with transurethral ultrasound heating applicators incorporating planar transducers.

Body Temperature↗
PubMed2006

Magnetic resonance imaging correlated with the histopathological effect of Pd-bacteriopheophorbide (Tookad) photodynamic therapy on the normal canine prostate gland.

BACKGROUND AND OBJECTIVE: To determine the optimal magnetic resonance imaging (MRI) methodology to assess photodynamic therapy (PDT)-induced histopathological responses in the prostate. STUDY DESIGN/MATERIALS AND METHODS: Laparotomy was performed in five healthy dogs. Cylindrical diffuser was placed in the prostates to deliver light of 50-300 J/cm at 150 mW/cm and 763 nm to activate IV-injected Tookad (1 mg/kg b.w.). Fast spin echo (FSE) T2-weighted, post-contrast-enhanced T1-(CE-T1) and diffusion weighted images (DWI) were obtained pre- and 2 days, 7 days, and 1 month post-PDT. Radiological-histopathological correlation was performed at 7 days (n = 4) and 1 month (n = 1) after PDT. A qualitative assessment of signal changes and apparent diffusion coefficient (ADC) mapping was performed. RESULTS: At 2 or 7 days post-PDT, there was good spatial correlation between PDT-induced hemorrhagic necrosis and unenhanced regions on CE-T1 images. There was a rapidly and persistently enhancing rim corresponding to edema and inflammation. FSE T2 and DWI showed altered signal but did not clearly define necrosis in all cases. At 1 month, it was hard to correlate MR images to histopathologic changes as they represented a mixture of necrosis and developing fibrosis, which led to a mixed signal intensity and less demarcated contrast enhancement. CONCLUSIONS: At 7 days after PDT, gadolinium DTPA contrast-enhanced MRI is superior to DWI and T2 imaging in assessing the boundary of Tookad PDT-induced tissue necrosis in the normal canine prostate.

Animals↗
PubMed2006

Comparison of CT histogram analysis and chemical shift MRI in the characterization of indeterminate adrenal nodules.

OBJECTIVE: Adrenal nodules having an attenuation of more than 10 H on unenhanced CT are considered indeterminate. The purpose of this study was to compare CT histogram analysis and chemical shift MRI in the characterization of indeterminate adrenal nodules. MATERIALS AND METHODS: Thirty-nine adrenal masses that were indeterminate on CT were identified in 37 patients. Histogram analysis was performed on unenhanced CT from a region of interest (ROI) that recorded mean attenuation, number of pixels, and percentage of negative pixels. MR signal intensity drop between the in- and opposed-phase images was measured for the masses. Analyses to determine whether correlations existed among the mean CT attenuation, percentage of negative pixels, and MR signal intensity drop were performed. A final diagnosis was obtained by pathology results, follow-up of more than 6 months, or adrenal washout CT findings. RESULTS: Negative pixels were present in 25 of 28 adenomas and nine of 11 nonadenomas. A threshold of more than 10% negative pixels for the diagnosis of adenoma provided a sensitivity of 46% and specificity of 100%. A threshold of more than 20% MR signal intensity drop yielded a sensitivity of 71% and specificity of 100%. An increase in the percentage of negative pixels was correlated with a decrease in mean CT attenuation. Using MRI, observers characterized seven additional nodules as adenomas compared with CT histogram analysis (McNemar test, chi2 = 5.1429; p = 0.023). CONCLUSION: CT histogram analysis with a threshold of a 10% negative pixel presence increases sensitivity for the characterization of adenomas compared with analysis of the mean CT attenuation alone. The use of chemical shift MRI with a threshold of 20% signal intensity drop results in a higher sensitivity than CT histogram analysis.

Adenoma↗
PubMed2006

Adenocarcinoma involving the uterine cervix: magnetic resonance imaging findings in tumours of endometrial, compared with cervical, origin.

PURPOSE: To determine the distinctive magnetic resonance imaging (MRI) features of cervical and endometrial adenocarcinoma that present clinically as a cervical mass. MATERIALS AND METHODS: From 1999 to 2002, 56 patients with adenocarcinoma on the initial biopsy of a cervical mass underwent MRI at our institution. Of these, 42 had a visible mass on MRI. Pathology review of all available tissue was the reference standard. A site of origin was determined by the pathologist in 38 of the 42 patients, and these were the cases evaluated; of these patients, 32 cases had adenocarcinoma and 6 had adenosquamous cancers. RESULTS: Findings were significantly more prevalent in patients with adenocarcinomas of endometrial, compared with cervical, origin for endometrial thickening (11 [73%] and 3 [13%], respectively; P = 0.0003), endometrial mass (11 [73%] and 1 [4%], respectively; P < 0.0001), endometrial cavity expansion by a mass (9 [60%] and 2 [9%], respectively; P = 0.001), and invasion of myometrium from endometrium (9 [60%] and 0, respectively; P < 0.0001). CONCLUSION: Adenocarcinomas of the endometrium that involve the cervix have MRI features that help distinguish them from primary adenocarcinomas of the cervix.

Adenocarcinoma↗
PubMed2005

Method for MRI-guided conformal thermal therapy of prostate with planar transurethral ultrasound heating applicators.

A method for conformal prostate thermal therapy using transurethral ultrasound heating applicators incorporating planar transducers is described. The capability to shape heating patterns to the geometry of the prostate gland from a single element in a multi-element heating applicator was evaluated using Bioheat transfer modelling. Eleven prostate geometries were obtained from patients who underwent MR imaging of the prostate gland prior to radical prostatectomy. Results indicate that ultrasound heating applicators incorporating multi-frequency planar transducers (4 x 20 mm, f = 4.7 MHz, 9.7 MHz) are capable of shaping thermal damage patterns to the geometry of individual prostates. A temperature feedback control algorithm has been developed to control the frequency, rotation rate and applied power level from transurethral heating applicators based on measurements of the boundary temperature during heating. The discrepancy between the thermal damage boundary and the target boundary was less than 5 mm, and the transition distance between coagulation and normal tissue was less than 1 cm. Treatment times for large prostate volumes were less than 50 min, and perfusion did not have significant impact on the control algorithm. Rectal cooling will play an important role in reducing undesired heating near the rectal wall. Experimental validation of the simulations in a tissue-mimicking gel phantom demonstrated good agreement between the predicted and generated patterns of thermal damage.

Acoustics↗
PubMed2005

Assessment of the tumor microenvironment in cervix cancer using dynamic contrast enhanced CT, interstitial fluid pressure and oxygen measurements.

PURPOSE: Interstitial fluid pressure (IFP) and oxygen (pO(2)) measurements are prognostic factors in cervical cancer. The purpose of this study was to determine the relationship between IFP and oxygenation and parameters derived from dynamic contrast-enhanced computed tomography (DCE-CT). METHODS AND MATERIALS: Dynamic contrast-enhanced computed tomography was performed in 32 patients with cervical cancer before radiation therapy. Images were acquired during intravenous contrast injection at 1 per s for 120 s and 1 per 15 s for 60 s. DCE-CT was analyzed using CT Perfusion 3 software (GE Medical Systems) to derive tumor blood flow (BF), permeability surface area product, blood volume, and mean transit time. Further analysis was performed to obtain relative peak enhancement, residual enhancement at 3 min after contrast injection (RE), time to peak and initial slope. Nodal status and tumor size were assessed with MRI. From in vivo IFP (n = 31) and pO(2) (n = 31) tumor measurements median pO(2) (mO(2)), percentage measurements less than 5 mm Hg (HP5) and mean IFP values were calculated. RESULTS: There was a positive correlation between BF and mO(2) (r = 0.47, p = 0.007) and between RE and HP5 (r = 0.39, p = 0.03). There was no correlation between IFP and DCE-CT parameters. CONCLUSION: There is a moderately positive, correlation between tumor oxygenation and BF as well as RE and HP5. Further study is required to determine if DCE-CT parameters are useful predictors of tumor behavior in cervical cancer.

Extracellular Fluid↗
PubMed2005

Role of magnetic resonance cholangiography in assessing biliary anatomy in right lobe living donors.

BACKGROUND: The value of magnetic resonance cholangiography (MRC) in assessing potential adult-to-adult living liver transplant (ALDLT) donors remains poorly defined. The purpose of this study is to determine the accuracy of MRC in assessing biliary anatomy with intraoperative confirmation. METHODS: A prospective cohort of 30 ALDLT donors who underwent right hepatectomy from October 2000 to July 2003 was evaluated. MRC was performed using a heavily T2 weighted radial slab technique. MRC was interpreted preoperatively by a radiologist and a surgeon and compared with the intraoperative biliary findings in all patients derived from cholangiography (IOC) and bile duct exploration. The sensitivity, specificity, and positive and negative predictive values of MRC for aberrant biliary anatomy were calculated. RESULTS: MRC suggested normal, aberrant, and indeterminate biliary anatomy in 16, 12, and 2 donors, respectively. IOC revealed normal and aberrant biliary anatomy in 17 and 13 patients, respectively. MRC demonstrated biliary anatomy accurately in 27 of 30 patients. The sensitivity, specificity, positive predictive, and negative predictive values of MRC in detecting aberrant biliary anatomy were 92%, 100%, 100%, and 94%, respectively. CONCLUSIONS: Preoperative MRC accurately depicts biliary anatomy in potential ALDLT donors and may guide the intraoperative management of the biliary tract.

Adult↗
PubMed2005

Fungal liver infection in immunocompromised patients: depiction with multiphasic contrast-enhanced helical CT.

PURPOSE: To retrospectively assess multiphasic (nonenhanced, arterial phase, and portal venous phase) computed tomography (CT) of the liver for depiction of hepatic fungal infection in immunocompromised patients. MATERIALS AND METHODS: The institutional ethics review board approved the study and waived the requirement for informed consent. Sixty multiphasic hepatic CT examinations were performed in 39 immunocompromised patients who fulfilled the criteria for having probable or proved fungal liver infection. The detection and conspicuity of focal liver lesions were assessed on scans obtained during each CT phase. The lesion enhancement pattern was determined, and, accordingly, lesions were stratified into two groups: lesions suggestive of infection (with ring enhancement patterns or high attenuation) and nonspecific hypoattenuating lesions. Statistical analyses were performed by using logistic regression with generalized estimating equations. RESULTS: A total of 536 liver lesions detected at 36 CT examinations with results positive for fungal infection were assessed. All 36 (100%) examinations yielded positive results during the arterial phase, whereas 25 (69%) of them yielded positive results during the portal venous phase (P < .001). At lesion-by-lesion analysis, the arterial phase scans depicted significantly more lesions (483 of 536 [90%]) than the portal venous phase (329 of 536 [61%]) and nonenhanced (265 of 465 [57%]) scans (P < .001 for both comparisons). In addition, on arterial phase scans, 386 of 483 lesions, as compared with 134 of 329 lesions on portal venous phase scans (P < .001), were judged to have an enhancement pattern suggestive of infection. The CT phases did not differ significantly in terms of the conspicuity of detected lesions. CONCLUSION: In patients suspected of having hepatic fungal infection, arterial phase CT depicts significantly more hepatic lesions than does CT performed during the other phases, and it reveals more lesions with enhancement patterns suggestive of infection. Arterial phase CT should be performed in addition to portal venous phase CT in patients suspected of having hepatic fungal infection.

Adolescent↗
PubMed2005

Renal colic: comparison of use and outcomes of unenhanced helical CT for emergency investigation in 1998 and 2002.

PURPOSE: To determine retrospectively whether there had been any change between 1998 and 2002 in the use and outcome of computed tomography (CT) performed in the emergency department for patients presenting with symptoms of renal colic. MATERIALS AND METHODS: Approval from the Research Ethics Board was obtained, and informed consent was waived. All CT examinations ordered from the emergency department of a tertiary care hospital and performed from July to December 1998 and July to December 2002 were identified. Reports were reviewed, and results were categorized as either (a) positive for urinary tract calculus disease (category I), (b) indicative of an alternate diagnosis (category II), or (c) negative for findings to account for the patient's symptoms (category III). The corresponding emergency department charts were reviewed for urine dipstick results for hematuria and for patient history of stone disease. For statistical analysis, chi2 testing and odds ratios were used. RESULTS: During the 6-month period in 1998, 179 CT examinations were performed in patients who were admitted to the emergency department. During the same period in 2002, 234 CT examinations were performed. After correction for the total number of emergency department visits, it was determined that there was a relative increase of 21.3% (95% confidence interval: -0.0009, 0.47) in number of CT examinations performed in the emergency department. A total of 117 (65.4%) of 179 CT studies in 1998 and 153 (65.4%) of 234 CT studies in 2002 demonstrated renal calculus disease (category I), nine (5.0%) of 179 CT studies in 1998 and 17 (7.3%) of 234 CT studies in 2002 were used to identify an alternate diagnosis for patient symptoms (category II), and 53 (29.6%) of 179 CT studies in 1998 and 64 (27.4%) of 234 CT studies in 2002 were negative (category III). There were no significant differences between the rates of category I, II, or III results and the positivity rates for hematuria and urinary tract stone history during 1998 and 2002. CONCLUSION: Despite a definite trend of increased CT use during 1998 and 2002, there was no significant decrease in the rates of positive renal colic results or alternate diagnoses.

Adult↗
PubMed2005

Relationship between vascular and biliary anatomy in living liver donors.

OBJECTIVE: The objective of our study was to determine whether there is an association between portal venous or hepatic arterial branching patterns (or both) and biliary anatomic variants. MATERIALS AND METHODS: Two radiologists independently reviewed preoperative hepatic CT scans and intraoperative cholangiograms from 39 consecutive living liver donors. The portal venous and hepatic arterial anatomy was classified on the basis of the preoperative CT scans and the biliary anatomy was classified on the basis the intraoperative cholangiograms into one of two groups: conventional or anomalous. Variables were tested for association using Fisher's exact test. RESULTS: Anomalous vascular branching variants were common, being present in 23 (59%) of 39 patients. Hepatic arterial anomalies were present in 18 (46%); portal venous anomalies, in seven (18%); and both, in two (5%). Biliary anomalies were present in 15 (38%) of the 39 patients. Of the 23 patients with anomalous vascular anatomy, seven (30%) had biliary anomalies. Of the 16 patients with conventional vascular anatomy, eight (50%) had biliary anomalies. There was no significant association between hepatic arterial anomalies, portal venous anomalies, or the combination of arterial and portal venous anomalies and anomalous biliary drainage. CONCLUSION: Portal venous and hepatic arterial branching patterns do not correlate well with biliary anatomic variants. In patients with normal hepatic vascular anatomy, biliary anomalies are common.

Adult↗
PubMed2004

Chemical shift MR imaging of hyperattenuating (>10 HU) adrenal masses: does it still have a role?

PURPOSE: To evaluate chemical shift magnetic resonance (MR) imaging for the characterization of hyperattenuating adrenal masses. MATERIALS AND METHODS: Adrenal MR images obtained from January 1998 to February 2003 were reviewed. Patients were excluded if they did not undergo unenhanced computed tomography or did not have an adrenal mass with attenuation higher than 10 HU, adequate follow-up, or pathologic diagnosis for use as a reference standard. A diagnosis of adenoma required at least 24 weeks of stability on images. Thirty-eight masses in 36 patients were identified (27 adenomas, nine metastases, one adrenocortical oncocytoma, and one pheochromocytoma). Signal intensity (SI) decrease between in-phase and opposed-phase MR images was measured for the entire mass and normalized to the renal parenchymal SI. In 21 of 36 (58%) patients, dual-echo single-breath-hold MR imaging was used to eliminate misregistration. RESULTS: The attenuation of 61% (23 of 38) of all masses and 70% (19 of 27) of adenomas was 10-30 HU. With a threshold of 20% SI decrease, the sensitivity of chemical shift MR imaging for hyperattenuating adenoma was 67% (18 of 27 masses). When considering masses with attenuation of 10-30 HU, the sensitivity for adenoma was 89% (17 of 19 masses) and remained reasonable at 75% (six of eight masses) for adenomas with attenuation of 20-30 HU. Only one adenoma with attenuation higher than 30 HU had SI decrease of more than 20%. Specificity for diagnosis of adenoma was 100% (11 of 11). CONCLUSION: In certain circumstances, chemical shift MR imaging is a reasonable second imaging test for further characterization of a hyperattenuating adrenal mass.

Adenoma↗
PubMed2004

The natural history of incidentally detected small renal masses.

BACKGROUND: The incidence of renal cell carcinoma (RCC) is increasing, largely due to the widespread use of cross-sectional imaging. Most renal tumors are detected incidentally as small, asymptomatic masses. To study their natural history, the authors prospectively followed a series of patients with this type of lesion who were unsuited for or refused surgery. METHODS: Twenty-nine patients with 32 masses that measured < 4 cm in greatest dimension (25 solid masses and 7 complex cystic masses) were studied. The primary outcome was tumor size, which was calculated as volume over time. All patients were followed with serial abdominal imaging, and each mass had at least three follow-up measurements. The median follow-up was 27.9 months (range, 5.3-143.0 months). RESULTS: Overall, the average growth rate did not differ statistically from zero growth (P = 0.09; 95% confidence interval, - 0.005-0.2 cm per year) and was not associated with either initial size (P = 0.28) or mass type (P = 0.41). Seven masses (22%) reached 4 cm in greatest dimension after 12-85 months of follow-up. Eight masses (25%) doubled their volumes within 12 months. Overall, 11 masses (34%) fulfilled 1 of these 2 criteria of rapid growth. Nine tumors were removed surgically after an average of 3.1 years of follow-up because it was believed that they were growing fast. No patient had disease progression. CONCLUSIONS: Approximately one-third of small renal masses that are presumed RCCs grow if they are managed conservatively and are followed with serial imaging. The growth rate is slow or undetectable in the majority of patients. These observations raise the possibility of a period of initial observation in selected patients, particularly the elderly or infirm.

Adult↗
PubMed2003

Functional CT imaging of prostate cancer.

The purpose of this paper is to investigate the distribution of blood flow (F), mean capillary transit time (Tc), capillary permeability (PS) and blood volume (vb) in prostate cancer using contrast-enhanced CT. Nine stage T2-T3 prostate cancer patients were enrolled in the study. Following bolus injection of a contrast agent, a time series of CT images of the prostate was acquired. Functional maps showing the distribution of F, Tc, PS and vb within the prostate were generated using a distributed parameter tracer kinetic model, the adiabatic approximation to the tissue homogeneity model. The precision of the maps was assessed using covariance matrix analysis. Finally, maps were compared to the findings of standard clinical investigations. Eight of the functional maps demonstrated regions of increased F, PS and vb, the locations of which were consistent with the results of standard clinical investigations. However, model parameters other than F could only be measured precisely within regions of high F. In conclusion functional CT images of cancer-containing prostate glands demonstrate regions of elevated F, PS and Vb. However, caution should be used when applying a complex tracer kinetic model to the study of prostate cancer since not all parameters can be measured precisely in all areas.

Adenocarcinoma↗
PubMed2003

Proton magnetic resonance spectroscopy as a potential tool for differentiating between abdominal fluid collections.

PURPOSE: To determine the utility of proton magnetic resonance spectroscopy (MRS) in distinguishing abdominal fluid types. MATERIALS AND METHODS: Abdominal fluid samples were obtained from patients undergoing therapeutic percutaneous drainage. In vitro spectroscopy was performed using a 1.5-T scanner and a head coil. Single voxel spectra were obtained using a point resolved spin-echo sequence with water suppression (TR/TE 2000 msec/35 msec). The peak pattern for each sample was examined and the signal-to-noise ratio (SNR) estimated (ratio of tallest peak to noise at <0 ppm). RESULTS: Thirty-five samples were analyzed: purulent collection (eight), serosanguinous collection (eight), non-chylous ascites (six), chylous ascites (one), bile (seven), and bile with iodinated contrast media (five). The mean SNR of the dominant peak was: purulent collection, 12.7; serosanguinous collection, 3.2; non-chylous ascites, 2.4; chylous ascites, 8.8; bile, 1.4; and bile with contrast media, 60.8. Pus samples had a broad based peak pattern with continuous signal of >1.5 ppm width situated within the range 0.2-2.5 ppm, not found in other samples. Chylous ascites (one sample) had a distinctive peak at 1.2 ppm. Bile with contrast had three peaks at 3.5/3.6, 2.6, and 2.1 ppm. No other patterns were found to be discriminatory. Common non-specific patterns seen included a bifid peak at 1.1-1.3 ppm and a broad based peak situated between 3 and 4 ppm. CONCLUSIONS: The H1 spectra of purulent fluid has a higher SNR than common non-purulent abdominal fluids and a distinct broad based peak pattern from 0.2-2.5 ppm. Proton spectroscopy may be a useful tool for distinguishing purulent from non-purulent intra-abdominal collections.

Abdominal Abscess↗
PubMed2003

Interstitial microwave thermal therapy for prostate cancer.

Thermal therapy is used to kill tumors by heating them to temperatures >50 degrees C for an extended period of time. Cell death results from thermal coagulation. The energy sources available for this approach include radiofrequency electrodes, microwave antennas, laser fiberoptics, and ultrasound transducers. Each of these modalities has the potential to be delivered in a minimally invasive manner, and many theoretical and experimental investigations of these devices have been performed. This review describes current knowledge of interstitial microwave thermal therapy for prostate cancer. Examples are given from an ongoing trial in patients who have recurrent or persistent disease following radiation therapy. Future directions for pretreatment planning and real-time monitoring and control are discussed. These techniques have the potential to optimize treatments on a patient-specific basis and will be instrumental in planned future trials of this therapy as first line for prostate cancer.

Animals↗
PubMed2003

MR imaging findings and patterns of spread in secondary tumor involvement of the uterine body and cervix.

OBJECTIVE: Our study sought to describe the MR imaging features and the patterns of spread in secondary tumor involvement of the uterus by nonuterine tumors. CONCLUSION: Direct extension of an adjacent tumor to the uterus is the most common pattern of secondary tumor involvement. Concomitant invasion of other pelvic organs is also typical. Although less common, hematogenous or lymphatic metastases to the uterus are encountered in clinical practice. Metastases should be added to the differential diagnosis of apparently malignant masses in the uterine body or cervix, especially in patients with metastatic disease or in patients whose uterus shows a preserved shape with involvement by an infiltrative heterogeneously enhancing process.

Adolescent↗