Role of transrectal ultrasound guided salvage cryosurgery for recurrent prostate carcinoma after radiotherapy.

Despite improvements in treatment of localized prostate cancer, local recurrence remains a significant problem. A total of 46 patients with proven local cancer recurrence following external beam radiotherapy entered a prospective clinical trial using ultrasound-guided cryosurgery to ablate the residual prostate gland. Persistent complications included one urethra-rectal fistula, incontinence (2), retention (3), and treatment induced erectile dysfunction (7). Using the PSA definitions for biochemical failure as PSA>or=0.3 ng/ml, the Kaplan-Meier plots showed the incidence of patients to be free of biochemical recurrence at 51 and 44% at 1 and 2 y, respectively. For a PSA>or=1.0, the values at 1 and 2 y were 72 and 58%.

Indium-111 chloride scintigraphy in adult osteomyelitis.

Osteomyelitis is a common clinical problem that may be difficult to diagnose. We compared the performance of indium-111-labeled white cells ([111In]WBC) to 111In chloride ([111In]Cl) in two groups of adult patients suspected to have osteomyelitis or septic arthritis. Using [111In] WBC, 52 scans were performed on 51 patients. Nineteen patients had osteomyelitis. The sensitivity was 84% and specificity 82%. Using [111In]Cl, 48 scans were performed on 47 patients. Twelve had osteomyelitis. Sensitivity was 91%, and specificity was 89%. In each group, one false-negative study occurred in vertebral osteomyelitis. Three false-negative studies using [111In]WBC were due to failure to distinguish between combined bone and soft-tissue infection and soft-tissue infection alone. False-positive studies in both groups were due to overlying soft-tissue infection or inflammatory arthritis. Chi-squared test showed no significant difference in performance between the two agents. Indium-111 chloride is easier to prepare and use than [111In]WBC, which requires a time-consuming labeling process.

Image-guided central venous catheters for apheresis.

Apheresis is an increasingly important procedure in the treatment of a variety of conditions, sometimes performed via peripheral access because of concern over major complications associated with central venous catheter (CVC) placement. This study sought to determine the safety and success for ultrasound and fluoroscopically guided, non-tunneled dual lumen CVCs placed for apheresis. Prospective data collection was made of 200 attempted CVC placements in the radiology department utilizing real time sonographic guidance. The complications relating to placement were noted in all and the number of passes required for venepuncture and whether a single wall puncture was achieved was recorded in 185 cases. Duration of catheterization and reason for line removal were recorded in all. Our study group included 71 donors providing peripheral blood stem cells for allogeneic transplant. CVCs were successfully placed in all patients, 191 lines in the internal jugular and seven in the femoral vein. 86.5% required only a single pass and 80.5% with only anterior wall puncture. Inadvertent but clinically insignificant arterial puncture occurred in six (3%) cases. In no case did this prevent line placement. There were no other procedure-related complications. 173 (87.4%) catheters were removed the same day. No catheters were removed prematurely. There was one case of prolonged venous bleeding. Our study demonstrates the safety of central venous catheters for apheresis provided that duration of catheterization is short and real-time sonographic guidance is used for the puncture, and guide wire and catheter placement are confirmed fluoroscopically.

A model for the time dependent three-dimensional thermal distribution within iceballs surrounding multiple cryoprobes.

A time dependent three-dimensional finite difference model of iceball formation about multiple cryoprobes has been developed and compared to experimental data. Realistic three-dimensional probe geometry is specified and the number of cryoprobes, the cryoprobe cooling rates, and the locations of the probes are arbitrary inputs by the user. The simulation accounts for observed longitudinal thermal gradients along the cryoprobe tips. Thermal histories for several points around commercially available cryoprobes have been predicted within experimental error for one, three, and five probe configurations. The simulation can be used to generate isotherms within the iceball at arbitrary times. Volumes enclosed by the iceball and any isotherms may also be computed to give the ablative ratio, a measure of the iceball's killing efficiency. This ratio was calculated as the volume enclosed by a critical isotherm divided by the total volume of the iceball for assumed critical temperatures of -20 and -40 degrees C. The ablative ratio for a single probe is a continuously decreasing function of time but when multiple probe configurations are used the ablative ratio increases to a maximum and then essentially plateaus. Maximum values of 0.44 and 0.55 were observed for three and five probe configurations, respectively, with an assumed critical temperature of -20 degrees C. Assuming a critical temperature of -40 degrees C, maximum ablative ratios of 0.21 and 0.3 for three and five probe configurations, respectively, were observed.

X-ray CT monitoring of iceball growth and thermal distribution during cryosurgery.

X-ray CT is able to image the internal architecture of frozen tissue. Phantoms of distilled water, a saline-gelatin mixture, lard and a calf liver-gelatin suspension cooled by a plastic tube acting as a long liquid nitrogen cryoprobe were used to study the relationship between Hounsfield unit (HU) values and temperature. There is a signature change in HU value from unfrozen to completely frozen tissue. No discernible relation exists between temperature in a completely frozen tissue and its HU value for the temperature range achieved with commercial cryoprobes. However, such a relation does exist in the typically narrow region of phase change and it is this change in HU value that is the parameter of concern for quantitative monitoring of the freezing process. Calibration of temperature against change in HU value allows a limited set of isotherms to be generated in the phase change region for direct monitoring of iceball growth. The phase change temperature range, mid-phase change temperature and the absolute value of HU change from completely frozen to unfrozen tissue are shown to be sensitive to the medium. Modelling of the temperature distribution within the region of completely frozen phantom using the infinite cylinder solution to the Fourier heat equation allows the temperature history of the phantom to be predicted. A set of isotherms, generated using a combination of thermal modelling and calibrated HU values demonstrates the feasibility of routine x-ray CT assisted cryotherapy. Isotherm overlay will be a major aid to the cryosurgeon who adopts a fixed target temperature as the temperature below which there is a certainty of ablation of the diseased tissue.

A semi-empirical treatment planning model for optimization of multiprobe cryosurgery.

A model is presented for treatment planning of multiprobe cryosurgery. In this model a thermal simulation algorithm is used to generate temperature distribution from cryoprobes, visualize isotherms in the anatomical region of interest (ROI) and provide tools to assist estimation of the amount of freezing damage to the target and surrounding normal structures. Calculations may be performed for any given freezing time for the selected set of operation parameters. The thermal simulation is based on solving the transient heat conduction equation using finite element methods for a multiprobe geometry. As an example, a semi-empirical optimization of 2D placement of six cryoprobes and their thermal protocol for the first freeze cycle is presented. The effectiveness of the optimized treatment protocol was estimated by generating temperature-volume histograms and calculating the objective function for the anatomy of interest. Two phantom experiments were performed to verify isotherm locations predicted by calculations. A comparison of the predicted 0 degrees C isotherm with the actual iceball boundary imaged by x-ray CT demonstrated a spatial agreement within +/-2 mm.

Suppression of high-density artefacts in x-ray CT images using temporal digital subtraction with application to cryotherapy.

Image guidance in cryotherapy is usually performed using ultrasound. Although not currently in routine clinical use, x-ray CT imaging is an alternative means of guidance that can display the full 3D structure of the iceball, including frozen and unfrozen regions. However, the quality of x-ray CT images is compromised by the presence of high-density streak artefacts. To suppress these artefacts we applied temporal digital subtraction (TDS). This TDS method has the added advantage of improving the grey scale contrast between frozen and unfrozen tissue in the CT images. Two sets of CT images were taken of a phantom material, cryoprobes and a urethral warmer (UW) before and during the cryoprobe freeze cycle. The high density artefacts persisted in both image sets. TDS was performed on these two image sets using the corresponding mask image of unfrozen material and the same geometrical configuration of the cryoprobes and the UW. The resultant difference image had a significantly reduced artefact content. Thus TDS can be used to significantly suppress or eliminate high-density CT streak artefacts without reducing the metallic content of the cryoprobes. In vivo study needs to be conducted to establish the utility of this TDS procedure for CT assisted prostate or liver cryotherapy. Applying TDS in x-ray CT guided cryotherapy will facilitate estimation of the number and location of all frozen and unfrozen regions, potentially making cryotherapy safer and less operator dependent.

A model for the time-dependent thermal distribution within an iceball surrounding a cryoprobe.

The optimal cooling parameters to maximize cell necrosis in different types of tissue have yet to be determined. However, a critical isotherm is commonly adopted by cryosurgeons as a boundary of lethality for tissue. Locating this isotherm within an iceball is problematic due to the limitations of MRI, ultrasound and CT imaging modalities. This paper describes a time-dependent two-dimensional axisymmetric model of iceball formation about a single cryoprobe and extensively compares it with experimental data. Thermal histories for several points around a CRYOprobe are predicted to high accuracy (5 degrees C maximum discrepancy). A realistic three-dimensional probe geometry is specified and cryoprobe temperature may be arbitrarily set as a function of time in the model. Three-dimensional temperature distributions within the iceball, predicted by the model at different times, are presented. Isotherm locations, as calculated with the infinite cylinder approximation, are compared with those of the model in the most appropriate region of the iceball. Infinite cylinder approximations are shown to be inaccurate when applied to this commercial probe. Adopting the infinite cylinder approximation to locate the critical isotherm is shown to lead the user to an overestimate of the volume of target tissue enclosed by this isotherm which may lead to incomplete tumour ablation.

Histological findings in the prostate two years following cryosurgical ablation.

We examined the pathological findings from prostatic whole mounts obtained at post-mortem, 2 years following cryosurgical ablation of the prostate (CSAP), to evaluate the presence or absence of residual benign or malignant tissue. Whole prostates were obtained from two patients at post-mortem, in which the cause of death was not related to prostate cancer. The patients had received CSAP 24 and 30 months earlier, as the primary treatment for prostate cancer. Complete ablation of the gland was demonstrated in one case, with some residual viable benign glands in the transitional zone in the second case. These results suggest that localized prostate cancer can be successfully eradicated by CSAP.

Cryosurgery for malignant tumours of the liver.

OBJECTIVE: To evaluate the safety and efficacy of ultrasound-guided cryosurgery to treat malignant tumours of the liver. DESIGN: A prospective nonrandomized trial. The follow-up was complete and ranged from 8 to 35 months. SETTING: A university-affiliated hospital. PATIENTS: Ten patients with secondary malignant tumours of the liver; 1 with primary hepatoma. INTERVENTIONS: Computed portography for preoperative staging; laparotomy and ultrasonographic examination of the liver; cryosurgical ablation of liver tumours with or without a concomitant resection. Thirteen procedures were performed on 11 patients. MAIN OUTCOME MEASURES: Preoperative morbidity, disease-free and overall survival. RESULTS: Of 24 lesions frozen, the procedure on 4 lesions was considered a technical failure because of persistent disease. There were no perioperative deaths. One patient had a liver abscess that resolved with percutaneous drainage. One patient had a biliary fistula that resolved spontaneously, and one had a transient rise in the serum creatinine level. Of 11 patients treated, 7 had a recurrence in the liver (persistent disease in 2 and new liver metastases in 5); 2 of these patients died. One patient died of distant disease with no local recurrence. At the time of writing, one patient was alive with extrahepatic disease and no local recurrence and two were free of disease. CONCLUSIONS: Cryosurgery of the liver is a relatively safe procedure that allows treatment of otherwise unresectable malignant disease. Proof of long-term benefit requires further experience and follow-up.

Use of a moratorium to achieve consistent liquid nitrogen cryoprobe performance.

BACKGROUND AND OBJECTIVES: During liver cryosurgical procedures, the authors observed seriously inconsistent rates of iceball growth implying inconsistent probe cooling rates. This inconsistency can lead to several problems, most importantly, loss of precision and reliability in freezing the chosen volume of tissue. The observation led to investigation of the performance of the cryosurgery machine. METHODS: The performance of the Cryotech LCS 3000 with different moratorium periods was investigated. Freezing was performed in a gelatin phantom with thermocouple monitoring at the probe tip. RESULTS: It was determined that a moratorium period between unit filling and clinical use essentially eliminates the uncertainty in probe performance. The need for this arises from the design of the system. A full liquid nitrogen tank does not have the necessary pressure required to induce effective freezing. A partially filled tank increases vapor pressure in the storage dewar driving more liquid nitrogen through the probes, thus allowing a more reliable and faster freeze. CONCLUSION: The simple measure of introducing a moratorium period between filling the dewar with liquid nitrogen and its use in surgery allows partial evaporation of the nitrogen and enhances cryoprobe performance. This protocol modification may reduce the chance of inconsistent probe performance thus making liver cryosurgery more reliable.

Correlation between thermosensor temperature and transrectal ultrasonography during prostate cryoablation.

OBJECTIVE: To determine if the adequacy of freezing in the neurovascular bundle region of the prostate during prostate cryotherapy can be monitored by transrectal ultrasonography (TRUS). PATIENTS AND METHODS: The study group consisted of 11 patients undergoing TRUS-guided prostate cryotherapy. The actual temperature in the gland was monitored with thermosensors placed in each prostatic neurovascular bundle. The 2 cryo-operators, working together and blinded to the actual temperature, used sonographic observations to estimate the temperature at the neurovascular bundles every 2 minutes until they believed that the gland was adequately frozen. The congruity between the estimated and measured temperatures was analyzed to determine if the operators could accurately monitor the progress of cryoablation by ultrasonography. RESULTS: There were a total of 85 data points for which the operators thought tumoricidal cryo-injury had been achieved at the neurovascular bundles (temperature -20 degrees C or below). For these points the measured temperature was on average 6.0 degrees C warmer than the estimated temperature (standard deviation, 22). For operator estimates of -20 degrees C or below, the measured temperature was -20 degrees C or below for 37 (44%) data points, between -19 degrees C and 0 degree C for 32 (38%) and greater than 0 degree C for 16 (19%). CONCLUSIONS: The operators were not able to accurately predict subzero temperatures at the neurovascular bundle region by TRUS evaluation. Moreover, the bias and magnitude of the error were significant and might lead to inadequate freezing of the prostate during attempted cryoablation.

Embolization of the uterine arteries before termination of a 15-week cervical pregnancy.

The authors describe a patient with a 15-week cervical pregnancy after in-vitro fertilization. The pregnancy was safely aborted after preoperative embolization of the uterine arteries. Fertility was preserved.

US-guided puncture of the internal jugular vein: complications and anatomic considerations.

PURPOSE: To examine success and complication rates for ultrasound (US)-guided cannulation of the internal jugular vein (IJV) in comparison with blind techniques and to present the variations in anatomy of the IJV. MATERIALS AND METHODS: Data were prospectively collected for 869 cases of sonographically guided cannulation of the IJV. In all cases, the side of the puncture, procedural success or failure, and any immediate complications were recorded. In 764 (88%) cases, the number of passes required and whether a single- or double-wall puncture was used were recorded. In 690 (79%) cases, IJV diameter and depth were recorded, while its relationship to the common carotid artery (CCA) was noted in 659 (76%) cases. RESULTS: Cannulation was successful in 868 (99.9%) cases. Complications occurred in 20 (2.3%) cases. Eighty-seven percent of cannulations were achieved with one pass and 83% with a single-wall puncture. Success at first pass was significantly correlated with right-sided puncture and the diameter of the IJV. In 5.5% of cases, the IJV lay medial to the CCA, making successful cannulation with use of the landmark technique unlikely. CONCLUSIONS: US-guided cannulation of the IJV is superior to blind techniques, increasing the success rate and incidence of first pass cannulation and reducing the incidence of complications.

Ultrasound monitoring in cannulation of the internal jugular vein: anatomic and technical considerations.

OBJECTIVE: To examine the effect of variations in anatomic features and operator experience on the success and complication rates of sonographically monitored cannulation of the internal jugular vein. PATIENTS AND METHODS: The authors prospectively collected data for ultrasound-monitored cannulation of the internal jugular vein in 150 patients. In all cases the radiologist recorded the side of puncture, the number of passes needed, the number of vein punctures (one or two), whether the walls were opposed during puncture and any complications. For the last 80 patients the following information was also recorded: the distance from the skin to the internal jugular vein, the diameter of the vein with the Valsalva manoeuvre and the location of the vein relative to the carotid artery. All but three of the cannulations were performed by one of three radiologists, all of whom had at least 5 years of experience. RESULTS: Cannulation was successful in all of the patients, and the first pass was successful in 133 (88.7%). These results are better than those of blind placement techniques reported in the literature. The only complications were hematoma and carotid puncture, which both occurred in the same two patients (1.3%). There was no significant difference among the radiologists in the number of passes needed (one-way analysis of variance, p > 0.05). The number of passes was independent of anatomic factors, including depth from skin, vein diameter or relative location. However, significantly more passes were needed for left-side punctures than for right-side punctures (Student t-test, p < 0.05). CONCLUSIONS: Real-time ultrasound monitoring is superior to blind techniques in cannulation of the internal jugular vein because of its ease, accuracy and safety. Sonographic real-time monitoring minimizes the impact of anatomic factors on success and complication rates. It is a safe and efficacious approach that should be preferred in the placement of central lines.

A simplified method of gastropexy for transgastric enterostomy.

Radiological placement of gastrostomy tubes was first described in 1983. Percutaneous gastropexy to facilitate gastrostomy placement was reported in 1986. Debate has continued to this day regarding the necessity of gastric fixation. We describe our technique of a simplified gastropexy to facilitate transgastric enterostomy and advocate its more widespread use.

Apheresis: another indication for radiologically placed central venous catheters.

OBJECTIVE: Apheresis is an important technique, used increasingly for a variety of conditions. It is sometimes performed via peripheral access because of concern over major complications associated with central venous catheter (CVC) placement. This study was to determine the safety and success of radiologic placement of CVCs for apheresis. METHODS: Data were collected prospectively for 278 CVCs placed under real-time sonographic or fluoroscopic guidance in the radiology department. Complications were noted in all cases; the number of passes required for venipuncture and whether this was achieved with a single wall puncture were noted in 265 cases; duration of catheterization and reason for removal of the catheter were recorded in all cases. The study group included 83 donors providing peripheral blood stem cells for allogeneic transplant. RESULTS: CVCs were successfully placed in all patients, 269 in the internal jugular and 9 in the femoral vein. In 87% of cases, only a single pass was required, and in 80% of cases venipuncture was achieved with a single anterior wall puncture. There was inadvertent but clinically insignificant arterial puncture in 6 cases (2%). In no case did this prevent CVC placement. Most catheters (211/274, 77%) were removed the same day. Only 3 catheters were removed prematurely (1%), 1 because of infection and 2 because of clotting. There was 1 case of venous bleeding. CONCLUSION: CVCs are safe for apheresis if real-time sonographic guidance is used for the puncture, guide wire and catheter placement are confirmed fluoroscopically, and the duration of catheterization is short.

Quality-of-life outcomes for men treated with cryosurgery for localized prostate carcinoma.

BACKGROUND: Cryosurgery was introduced as an alternative to radiotherapy or radical prostatectomy in the mid-1960s. Although it met the primary objective of achieving local control, it was largely abandoned due to a high incidence of complications. Technologic advances in the areas of imaging and urethral warming have renewed interest in this treatment methodology. The aim of the current study was to determine the quality of life of men enrolled in a Phase II clinical trial of cryosurgery for the treatment of localized prostate carcinoma. METHODS: Men were administered the Functional Assessment of Cancer Treatment-Prostate (FACT-P) prior to their treatment and at 6 weeks and 3, 6, and 12 months posttreatment. RESULTS: By 12 months after cryosurgery, most of the FACT-P subscales had returned to pretreatment levels, following a decline in well-being immediately after cryosurgery. There were two exceptions to this general trend: At 12 months, impairments in social/family well-being and sexual function still remained. The average time to return to work after therapy was 3 weeks. Stay in hospital after treatment was limited to 1 day for 94% of the participants. Compared with men who received the standard treatments of radical prostatectomy and radical radiotherapy, men treated with cryosurgery appeared to have a similar quality of life, with perhaps the exception of decreased sexual function. CONCLUSIONS: The quality-of-life outcomes of this study support the current renewed interest in cryosurgery. The severe impairments reported in other studies were not seen in this sample. In fact, it appeared that all aspects of the participants' well-being had returned to pretreatment levels by 12 months, with the exception of sexual function.

Should anticoagulant therapy be stopped or reversed before venous intervention?

PURPOSE: To determine the safety of venous intervention and the incidence of complications in patients undergoing venous interventional radiological procedures while receiving anticoagulant therapy. METHOD: Data were collected prospectively for a 1-year period. One hundred patients receiving anticoagulant therapy underwent interventional radiological procedures requiring venous cannulation. Of these, 87 had documented prolonged bleeding times. There were 50 inferior vena cavograms obtained and filters placed (29 transfemoral, 21 transjugular), and 50 transfemoral pulmonary angiogram obtained, all in patients with thrombo-embolic disease who were receiving anticoagulant therapy. In most cases venous access was achieved with real-time sonographic guidance. RESULTS: Venous access was gained in all patients in all groups. There were 41/50 filter placements and 46/50 pulmonary angiograms performed in the patients with prolonged clotting times in or above the therapeutic range. There were no cases of arterial puncture and no cases of venous bleeding either during or after the procedures. No other complications were recorded. CONCLUSION: Venous intervention in patients receiving therapeutic anticoagulation is safe, with no complications reported in our series. There is no need to discontinue anticoagulant therapy in patients with life-threatening thrombo-embolic disease. Real-time sonographic guidance greatly facilitates venous cannulation and avoids inadvertent arterial puncture.

Image-guided central venous catheter placement for apheresis in allogeneic stem cell donors.

Peripheral blood stem cell harvest by apheresis is an increasingly important procedure utilized in the treatment of many malignancies. Whether autologous or allogeneic, it is frequently performed via peripheral access because of concern over major complications associated with central venous catheter placement. This study was to determine the safety and success, complications and premature failure rates for radiolocally placed ultrasound-guided non-tunneled central venous catheters placed for apheresis in a donor (allogeneic) population. One hundred central venous catheters were placed in ninety-one individuals for allogeneic stem cell harvest. Procedural success and complications relating to placement were noted in all. In 97 cases the number of needle passes required for venous cannulation and whether this was achieved with a single wall puncture was noted. Duration of catheterization and reason for removal were recorded in all cases. All catheters were placed by a right transjugular route. Venous cannulation and functioning line placement was achieved in every case; 92/97 (95%) required only a single needle pass and 84/97 (87%) only a single wall puncture. There were no placement related complications; 94 catheters were removed the same day with the remainder removed within 48 hr. All completed apheresis. Our study demonstrates the safe use of central venous catheters for apheresis in normal donors if ultrasound guidance is used for the puncture and the duration of catheterization is short.